Lichen

Annotated deducer.py

611:d1d907801d42
2017-02-23 Paul Boddie Replaced list comprehension usage. method-wrapper-for-context
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#!/usr/bin/env python
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"""
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Deduce types for usage observations.
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Copyright (C) 2014, 2015, 2016, 2017 Paul Boddie <paul@boddie.org.uk>
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This program is free software; you can redistribute it and/or modify it under
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the terms of the GNU General Public License as published by the Free Software
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Foundation; either version 3 of the License, or (at your option) any later
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version.
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This program is distributed in the hope that it will be useful, but WITHOUT
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ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
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details.
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You should have received a copy of the GNU General Public License along with
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this program.  If not, see <http://www.gnu.org/licenses/>.
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"""
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from common import first, get_assigned_attributes, \
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                   get_attrname_from_location, get_attrnames, \
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                   get_invoked_attributes, get_name_path, init_item, \
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                   sorted_output, CommonOutput
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from encoders import encode_access_location, \
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                     encode_constrained, encode_location, encode_usage, \
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                     get_kinds, test_label_for_kind, test_label_for_type
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from errors import DeduceError
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from os.path import join
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from referencing import combine_types, is_single_class_type, separate_types, \
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                        Reference
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class Deducer(CommonOutput):
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    "Deduce types in a program."
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    def __init__(self, importer, output):
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        """
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        Initialise an instance using the given 'importer' that will perform
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        deductions on the program information, writing the results to the given
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        'output' directory.
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        """
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        self.importer = importer
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        self.output = output
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        # Descendants of classes.
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        self.descendants = {}
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        self.init_descendants()
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        self.init_special_attributes()
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        # Map locations to usage in order to determine specific types.
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        self.location_index = {}
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        # Map access locations to definition locations.
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        self.access_index = {}
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        # Map aliases to accesses that define them.
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        self.alias_index = {}
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        # Map constant accesses to redefined accesses.
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        self.const_accesses = {}
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        self.const_accesses_rev = {}
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        # Map usage observations to assigned attributes.
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        self.assigned_attrs = {}
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        # Map usage observations to objects.
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        self.attr_class_types = {}
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        self.attr_instance_types = {}
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        self.attr_module_types = {}
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        # All known attribute names.
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        self.all_attrnames = set()
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        # Modified attributes from usage observations.
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        self.modified_attributes = {}
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        # Accesses that are assignments or invocations.
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        self.reference_assignments = set()
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        self.reference_invocations = {}
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        self.reference_invocations_unsuitable = {}
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        # Map locations to types, constrained indicators and attributes.
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        self.accessor_class_types = {}
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        self.accessor_instance_types = {}
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        self.accessor_module_types = {}
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        self.provider_class_types = {}
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        self.provider_instance_types = {}
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        self.provider_module_types = {}
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        self.accessor_constrained = set()
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        self.access_constrained = set()
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        self.referenced_attrs = {}
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        self.referenced_objects = {}
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        # Details of access operations.
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        self.access_plans = {}
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        # Accumulated information about accessors and providers.
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        self.accessor_general_class_types = {}
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        self.accessor_general_instance_types = {}
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        self.accessor_general_module_types = {}
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        self.accessor_all_types = {}
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        self.accessor_all_general_types = {}
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        self.provider_all_types = {}
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        self.accessor_guard_tests = {}
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        # Accumulated information about accessed attributes and
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        # access/attribute-specific accessor tests.
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        self.reference_all_attrs = {}
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        self.reference_all_attrtypes = {}
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        self.reference_all_accessor_types = {}
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        self.reference_all_accessor_general_types = {}
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        self.reference_test_types = {}
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        self.reference_test_accessor_type = {}
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        # The processing workflow itself.
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        self.init_usage_index()
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        self.init_attr_type_indexes()
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        self.init_combined_attribute_index()
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        self.init_accessors()
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        self.init_accesses()
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        self.init_aliases()
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        self.modify_mutated_attributes()
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        self.identify_references()
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        self.classify_accessors()
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        self.classify_accesses()
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        self.initialise_access_plans()
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        self.identify_dependencies()
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    def to_output(self):
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        "Write the output files using deduction information."
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        self.check_output()
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        self.write_mutations()
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        self.write_accessors()
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        self.write_accesses()
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        self.write_access_plans()
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    def write_mutations(self):
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        """
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        Write mutation-related output in the following format:
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        qualified name " " original object type
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        Object type can be "<class>", "<function>" or "<var>".
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        """
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        f = open(join(self.output, "mutations"), "w")
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        try:
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            attrs = self.modified_attributes.items()
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            attrs.sort()
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            for attr, value in attrs:
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                print >>f, attr, value
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        finally:
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            f.close()
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    def write_accessors(self):
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        """
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        Write reference-related output in the following format for types:
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        location " " ( "constrained" | "deduced" ) " " attribute type " " most general type names " " number of specific types
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        Note that multiple lines can be given for each location, one for each
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        attribute type.
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        Locations have the following format:
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        qualified name of scope "." local name ":" name version
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        The attribute type can be "<class>", "<instance>", "<module>" or "<>",
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        where the latter indicates an absence of suitable references.
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        Type names indicate the type providing the attributes, being either a
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        class or module qualified name.
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        ----
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        A summary of accessor types is formatted as follows:
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        location " " ( "constrained" | "deduced" ) " " ( "specific" | "common" | "unguarded" ) " " most general type names " " number of specific types
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        This summary groups all attribute types (class, instance, module) into a
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        single line in order to determine the complexity of identifying an
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        accessor.
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        ----
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        References that cannot be supported by any types are written to a
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        warnings file in the following format:
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        location
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        ----
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        For each location where a guard would be asserted to guarantee the
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        nature of an object, the following format is employed:
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        location " " ( "specific" | "common" ) " " object kind " " object types
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        Object kind can be "<class>", "<instance>" or "<module>".
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        """
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        f_type_summary = open(join(self.output, "type_summary"), "w")
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        f_types = open(join(self.output, "types"), "w")
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        f_warnings = open(join(self.output, "type_warnings"), "w")
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        f_guards = open(join(self.output, "guards"), "w")
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        try:
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            locations = self.accessor_class_types.keys()
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            locations.sort()
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            for location in locations:
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                constrained = location in self.accessor_constrained
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                # Accessor information.
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                class_types = self.accessor_class_types[location]
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                instance_types = self.accessor_instance_types[location]
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                module_types = self.accessor_module_types[location]
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                general_class_types = self.accessor_general_class_types[location]
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                general_instance_types = self.accessor_general_instance_types[location]
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                general_module_types = self.accessor_general_module_types[location]
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                all_types = self.accessor_all_types[location]
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                all_general_types = self.accessor_all_general_types[location]
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                if class_types:
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                    print >>f_types, encode_location(location), encode_constrained(constrained), "<class>", \
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                        sorted_output(general_class_types), len(class_types)
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                if instance_types:
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                    print >>f_types, encode_location(location), encode_constrained(constrained), "<instance>", \
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                        sorted_output(general_instance_types), len(instance_types)
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                if module_types:
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                    print >>f_types, encode_location(location), encode_constrained(constrained), "<module>", \
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                        sorted_output(general_module_types), len(module_types)
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                if not all_types:
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                    print >>f_types, encode_location(location), "deduced", "<>", 0
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                    attrnames = list(self.location_index[location])
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                    attrnames.sort()
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                    print >>f_warnings, encode_location(location), "; ".join(map(encode_usage, attrnames))
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                guard_test = self.accessor_guard_tests.get(location)
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                if guard_test:
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                    guard_test_type, guard_test_arg = guard_test
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                # Write specific type guard details.
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                if guard_test and guard_test_type == "specific":
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                    print >>f_guards, encode_location(location), "-".join(guard_test), \
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                        first(get_kinds(all_types)), \
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                        sorted_output(all_types)
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                # Write common type guard details.
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                elif guard_test and guard_test_type == "common":
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                    print >>f_guards, encode_location(location), "-".join(guard_test), \
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                        first(get_kinds(all_general_types)), \
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                        sorted_output(all_general_types)
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                print >>f_type_summary, encode_location(location), encode_constrained(constrained), \
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                    guard_test and "-".join(guard_test) or "unguarded", sorted_output(all_general_types), len(all_types)
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        finally:
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            f_type_summary.close()
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            f_types.close()
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            f_warnings.close()
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            f_guards.close()
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    def write_accesses(self):
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        """
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        Specific attribute output is produced in the following format:
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        location " " ( "constrained" | "deduced" ) " " attribute type " " attribute references
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        Note that multiple lines can be given for each location and attribute
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        name, one for each attribute type.
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        Locations have the following format:
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        qualified name of scope "." local name " " attribute name ":" access number
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        The attribute type can be "<class>", "<instance>", "<module>" or "<>",
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        where the latter indicates an absence of suitable references.
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        Attribute references have the following format:
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        object type ":" qualified name
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        Object type can be "<class>", "<function>" or "<var>".
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        ----
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        A summary of attributes is formatted as follows:
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        location " " attribute name " " ( "constrained" | "deduced" ) " " test " " attribute references
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        This summary groups all attribute types (class, instance, module) into a
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        single line in order to determine the complexity of each access.
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        Tests can be "validate", "specific", "untested", "guarded-validate" or "guarded-specific".
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        ----
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        For each access where a test would be asserted to guarantee the
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        nature of an attribute, the following formats are employed:
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        location " " attribute name " " "validate"
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        location " " attribute name " " "specific" " " attribute type " " object type
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        ----
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        References that cannot be supported by any types are written to a
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        warnings file in the following format:
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        location
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        """
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        f_attr_summary = open(join(self.output, "attribute_summary"), "w")
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        f_attrs = open(join(self.output, "attributes"), "w")
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        f_tests = open(join(self.output, "tests"), "w")
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        f_warnings = open(join(self.output, "attribute_warnings"), "w")
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        f_unsuitable = open(join(self.output, "invocation_warnings"), "w")
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        try:
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            locations = self.referenced_attrs.keys()
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            locations.sort()
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            for location in locations:
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                constrained = location in self.access_constrained
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                # Attribute information, both name-based and anonymous.
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                referenced_attrs = self.referenced_attrs[location]
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                if referenced_attrs:
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                    attrname = get_attrname_from_location(location)
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                    all_accessed_attrs = self.reference_all_attrs[location]
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                    for attrtype, attrs in self.get_referenced_attrs(location):
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                        print >>f_attrs, encode_access_location(location), encode_constrained(constrained), attrtype, sorted_output(attrs)
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                    test_type = self.reference_test_types.get(location)
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                    # Write the need to test at run time.
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                    if test_type[0] == "validate":
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                        print >>f_tests, encode_access_location(location), "-".join(test_type)
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                    # Write any type checks for anonymous accesses.
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                    elif test_type and self.reference_test_accessor_type.get(location):
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                        print >>f_tests, encode_access_location(location), "-".join(test_type), \
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                            sorted_output(all_accessed_attrs), \
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                            self.reference_test_accessor_type[location]
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                    print >>f_attr_summary, encode_access_location(location), encode_constrained(constrained), \
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                        test_type and "-".join(test_type) or "untested", sorted_output(all_accessed_attrs)
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                    # Write details of potentially unsuitable invocation
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                    # occurrences.
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                    unsuitable = self.reference_invocations_unsuitable.get(location)
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                    if unsuitable:
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                        unsuitable = map(str, unsuitable)
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                        unsuitable.sort()
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                        print >>f_unsuitable, encode_access_location(location), ", ".join(unsuitable)
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                else:
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                    print >>f_warnings, encode_access_location(location)
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        finally:
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            f_attr_summary.close()
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            f_attrs.close()
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            f_tests.close()
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            f_warnings.close()
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            f_unsuitable.close()
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    def write_access_plans(self):
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        """
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        Each attribute access is written out as a plan of the following form:
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        location " " name " " test " " test type " " base " " traversed attributes
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                 " " attributes to traverse " " context " " access method
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                 " " static attribute " " accessor kinds
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        """
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        f_attrs = open(join(self.output, "attribute_plans"), "w")
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        try:
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            locations = self.access_plans.keys()
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            locations.sort()
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            for location in locations:
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                name, test, test_type, base, \
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                    traversed, traversal_modes, attrnames, \
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                    context, context_test, \
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                    first_method, final_method, \
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                    attr, accessor_kinds = self.access_plans[location]
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                print >>f_attrs, encode_access_location(location), \
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                                 name or "{}", \
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                                 test and "-".join(test) or "{}", \
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                                 test_type or "{}", \
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                                 base or "{}", \
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                                 ".".join(traversed) or "{}", \
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                                 ".".join(traversal_modes) or "{}", \
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                                 ".".join(attrnames) or "{}", \
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                                 context, context_test, \
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                                 first_method, final_method, attr or "{}", \
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                                 ",".join(accessor_kinds)
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        finally:
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            f_attrs.close()
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    def classify_accessors(self):
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        "For each program location, classify accessors."
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        # Where instance and module types are defined, class types are also
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        # defined. See: init_definition_details
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        locations = self.accessor_class_types.keys()
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        for location in locations:
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            constrained = location in self.accessor_constrained
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            # Provider information.
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            class_types = self.provider_class_types[location]
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            instance_types = self.provider_instance_types[location]
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            module_types = self.provider_module_types[location]
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            # Collect specific and general type information.
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            self.provider_all_types[location] = \
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                combine_types(class_types, instance_types, module_types)
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            # Accessor information.
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            class_types = self.accessor_class_types[location]
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            self.accessor_general_class_types[location] = \
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                general_class_types = self.get_most_general_class_types(class_types)
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            instance_types = self.accessor_instance_types[location]
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            self.accessor_general_instance_types[location] = \
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                general_instance_types = self.get_most_general_class_types(instance_types)
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            module_types = self.accessor_module_types[location]
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            self.accessor_general_module_types[location] = \
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                general_module_types = self.get_most_general_module_types(module_types)
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            # Collect specific and general type information.
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            self.accessor_all_types[location] = all_types = \
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                combine_types(class_types, instance_types, module_types)
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            self.accessor_all_general_types[location] = all_general_types = \
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                combine_types(general_class_types, general_instance_types, general_module_types)
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            # Record guard information.
paul@44 491
paul@44 492
            if not constrained:
paul@44 493
paul@44 494
                # Record specific type guard details.
paul@44 495
paul@44 496
                if len(all_types) == 1:
paul@237 497
                    self.accessor_guard_tests[location] = ("specific", test_label_for_type(first(all_types)))
paul@57 498
                elif is_single_class_type(all_types):
paul@237 499
                    self.accessor_guard_tests[location] = ("specific", "object")
paul@44 500
paul@44 501
                # Record common type guard details.
paul@44 502
paul@44 503
                elif len(all_general_types) == 1:
paul@237 504
                    self.accessor_guard_tests[location] = ("common", test_label_for_type(first(all_types)))
paul@57 505
                elif is_single_class_type(all_general_types):
paul@237 506
                    self.accessor_guard_tests[location] = ("common", "object")
paul@44 507
paul@44 508
                # Otherwise, no convenient guard can be defined.
paul@44 509
paul@44 510
    def classify_accesses(self):
paul@44 511
paul@44 512
        "For each program location, classify accesses."
paul@44 513
paul@44 514
        # Attribute accesses use potentially different locations to those of
paul@44 515
        # accessors.
paul@44 516
paul@44 517
        locations = self.referenced_attrs.keys()
paul@44 518
paul@44 519
        for location in locations:
paul@44 520
            constrained = location in self.access_constrained
paul@44 521
paul@69 522
            # Combine type information from all accessors supplying the access.
paul@44 523
paul@44 524
            accessor_locations = self.get_accessors_for_access(location)
paul@44 525
paul@44 526
            all_provider_types = set()
paul@44 527
            all_accessor_types = set()
paul@44 528
            all_accessor_general_types = set()
paul@44 529
paul@44 530
            for accessor_location in accessor_locations:
paul@44 531
paul@44 532
                # Obtain the provider types for guard-related attribute access
paul@44 533
                # checks.
paul@44 534
paul@67 535
                all_provider_types.update(self.provider_all_types.get(accessor_location))
paul@67 536
paul@67 537
                # Obtain the accessor guard types (specific and general).
paul@67 538
paul@67 539
                all_accessor_types.update(self.accessor_all_types.get(accessor_location))
paul@67 540
                all_accessor_general_types.update(self.accessor_all_general_types.get(accessor_location))
paul@44 541
paul@70 542
            # Obtain basic properties of the types involved in the access.
paul@70 543
paul@70 544
            single_accessor_type = len(all_accessor_types) == 1
paul@70 545
            single_accessor_class_type = is_single_class_type(all_accessor_types)
paul@70 546
            single_accessor_general_type = len(all_accessor_general_types) == 1
paul@70 547
            single_accessor_general_class_type = is_single_class_type(all_accessor_general_types)
paul@70 548
paul@69 549
            # Determine whether the attribute access is guarded or not.
paul@44 550
paul@44 551
            guarded = (
paul@70 552
                single_accessor_type or single_accessor_class_type or
paul@70 553
                single_accessor_general_type or single_accessor_general_class_type
paul@44 554
                )
paul@44 555
paul@44 556
            if guarded:
paul@44 557
                (guard_class_types, guard_instance_types, guard_module_types,
paul@57 558
                    _function_types, _var_types) = separate_types(all_provider_types)
paul@44 559
paul@67 560
            self.reference_all_accessor_types[location] = all_accessor_types
paul@67 561
            self.reference_all_accessor_general_types[location] = all_accessor_general_types
paul@63 562
paul@44 563
            # Attribute information, both name-based and anonymous.
paul@44 564
paul@44 565
            referenced_attrs = self.referenced_attrs[location]
paul@44 566
paul@71 567
            if not referenced_attrs:
paul@187 568
                raise DeduceError("In %s, access via %s to attribute %s (occurrence %d) cannot be identified." % location)
paul@71 569
paul@71 570
            # Record attribute information for each name used on the
paul@71 571
            # accessor.
paul@71 572
paul@71 573
            attrname = get_attrname_from_location(location)
paul@71 574
paul@71 575
            all_accessed_attrs = set()
paul@71 576
            all_providers = set()
paul@71 577
paul@71 578
            # Obtain provider and attribute details for this kind of
paul@71 579
            # object.
paul@71 580
paul@71 581
            for attrtype, object_type, attr in referenced_attrs:
paul@71 582
                all_accessed_attrs.add(attr)
paul@71 583
                all_providers.add(object_type)
paul@71 584
paul@71 585
            all_general_providers = self.get_most_general_types(all_providers)
paul@71 586
paul@71 587
            # Determine which attributes would be provided by the
paul@71 588
            # accessor types upheld by a guard.
paul@71 589
paul@71 590
            if guarded:
paul@71 591
                guard_attrs = set()
paul@555 592
paul@71 593
                for _attrtype, object_type, attr in \
paul@555 594
                    self._identify_reference_attribute(location, attrname, guard_class_types, guard_instance_types, guard_module_types):
paul@555 595
paul@71 596
                    guard_attrs.add(attr)
paul@71 597
            else:
paul@71 598
                guard_attrs = None
paul@71 599
paul@71 600
            self.reference_all_attrs[location] = all_accessed_attrs
paul@71 601
paul@71 602
            # Constrained accesses guarantee the nature of the accessor.
paul@71 603
            # However, there may still be many types involved.
paul@71 604
paul@71 605
            if constrained:
paul@71 606
                if single_accessor_type:
paul@237 607
                    self.reference_test_types[location] = ("constrained", "specific", test_label_for_type(first(all_accessor_types)))
paul@71 608
                elif single_accessor_class_type:
paul@237 609
                    self.reference_test_types[location] = ("constrained", "specific", "object")
paul@71 610
                elif single_accessor_general_type:
paul@237 611
                    self.reference_test_types[location] = ("constrained", "common", test_label_for_type(first(all_accessor_general_types)))
paul@71 612
                elif single_accessor_general_class_type:
paul@237 613
                    self.reference_test_types[location] = ("constrained", "common", "object")
paul@44 614
                else:
paul@237 615
                    self.reference_test_types[location] = ("constrained", "many")
paul@71 616
paul@71 617
            # Suitably guarded accesses, where the nature of the
paul@71 618
            # accessor can be guaranteed, do not require the attribute
paul@71 619
            # involved to be validated. Otherwise, for unguarded
paul@71 620
            # accesses, access-level tests are required.
paul@71 621
paul@71 622
            elif guarded and all_accessed_attrs.issubset(guard_attrs):
paul@71 623
                if single_accessor_type:
paul@237 624
                    self.reference_test_types[location] = ("guarded", "specific", test_label_for_type(first(all_accessor_types)))
paul@71 625
                elif single_accessor_class_type:
paul@237 626
                    self.reference_test_types[location] = ("guarded", "specific", "object")
paul@71 627
                elif single_accessor_general_type:
paul@237 628
                    self.reference_test_types[location] = ("guarded", "common", test_label_for_type(first(all_accessor_general_types)))
paul@71 629
                elif single_accessor_general_class_type:
paul@237 630
                    self.reference_test_types[location] = ("guarded", "common", "object")
paul@71 631
paul@71 632
            # Record the need to test the type of anonymous and
paul@71 633
            # unconstrained accessors.
paul@71 634
paul@71 635
            elif len(all_providers) == 1:
paul@71 636
                provider = first(all_providers)
paul@71 637
                if provider != '__builtins__.object':
paul@71 638
                    all_accessor_kinds = set(get_kinds(all_accessor_types))
paul@71 639
                    if len(all_accessor_kinds) == 1:
paul@385 640
                        test_type = ("test", "specific", test_label_for_kind(first(all_accessor_kinds)))
paul@70 641
                    else:
paul@237 642
                        test_type = ("test", "specific", "object")
paul@71 643
                    self.reference_test_types[location] = test_type
paul@77 644
                    self.reference_test_accessor_type[location] = provider
paul@71 645
paul@71 646
            elif len(all_general_providers) == 1:
paul@71 647
                provider = first(all_general_providers)
paul@71 648
                if provider != '__builtins__.object':
paul@71 649
                    all_accessor_kinds = set(get_kinds(all_accessor_general_types))
paul@71 650
                    if len(all_accessor_kinds) == 1:
paul@385 651
                        test_type = ("test", "common", test_label_for_kind(first(all_accessor_kinds)))
paul@71 652
                    else:
paul@237 653
                        test_type = ("test", "common", "object")
paul@71 654
                    self.reference_test_types[location] = test_type
paul@77 655
                    self.reference_test_accessor_type[location] = provider
paul@71 656
paul@71 657
            # Record the need to test the identity of the attribute.
paul@71 658
paul@71 659
            else:
paul@237 660
                self.reference_test_types[location] = ("validate",)
paul@44 661
paul@67 662
    def initialise_access_plans(self):
paul@67 663
paul@67 664
        "Define attribute access plans."
paul@67 665
paul@67 666
        for location in self.referenced_attrs.keys():
paul@76 667
            original_location = self.const_accesses_rev.get(location)
paul@76 668
            self.access_plans[original_location or location] = self.get_access_plan(location)
paul@67 669
paul@411 670
    def identify_dependencies(self):
paul@411 671
paul@411 672
        "Introduce more module dependencies to the importer."
paul@411 673
paul@411 674
        for location, referenced_attrs in self.referenced_attrs.items():
paul@411 675
            path, name, attrnames, version = location
paul@411 676
paul@411 677
            # Identify module-level paths.
paul@411 678
paul@411 679
            if self.importer.modules.has_key(path):
paul@411 680
                module_name = path
paul@411 681
paul@411 682
            # Identify the module containing other paths.
paul@411 683
paul@411 684
            else:
paul@411 685
                ref = self.importer.identify(path)
paul@411 686
                for objpath in ref.ancestors():
paul@411 687
                    if self.importer.modules.has_key(objpath):
paul@411 688
                        module_name = objpath
paul@411 689
                        break
paul@411 690
                else:
paul@411 691
                    raise DeduceError("Cannot find module for path %s." % path)
paul@411 692
paul@418 693
            # Identify references providing dependencies.
paul@411 694
paul@411 695
            for attrtype, objtype, attr in referenced_attrs:
paul@423 696
                self.importer.add_dependency(path, attr.get_origin())
paul@411 697
paul@44 698
    def get_referenced_attrs(self, location):
paul@44 699
paul@44 700
        """
paul@44 701
        Return attributes referenced at the given access 'location' by the given
paul@44 702
        'attrname' as a list of (attribute type, attribute set) tuples.
paul@44 703
        """
paul@44 704
paul@69 705
        d = {}
paul@69 706
        for attrtype, objtype, attr in self.referenced_attrs[location]:
paul@69 707
            init_item(d, attrtype, set)
paul@246 708
            d[attrtype].add(attr.unaliased())
paul@69 709
        l = d.items()
paul@69 710
        l.sort() # class, module, instance
paul@44 711
        return l
paul@44 712
paul@44 713
    # Initialisation methods.
paul@44 714
paul@44 715
    def init_descendants(self):
paul@44 716
paul@44 717
        "Identify descendants of each class."
paul@44 718
paul@44 719
        for name in self.importer.classes.keys():
paul@44 720
            self.get_descendants_for_class(name)
paul@44 721
paul@44 722
    def get_descendants_for_class(self, name):
paul@44 723
paul@44 724
        """
paul@44 725
        Use subclass information to deduce the descendants for the class of the
paul@44 726
        given 'name'.
paul@44 727
        """
paul@44 728
paul@44 729
        if not self.descendants.has_key(name):
paul@44 730
            descendants = set()
paul@44 731
paul@44 732
            for subclass in self.importer.subclasses[name]:
paul@44 733
                descendants.update(self.get_descendants_for_class(subclass))
paul@44 734
                descendants.add(subclass)
paul@44 735
paul@44 736
            self.descendants[name] = descendants
paul@44 737
paul@44 738
        return self.descendants[name]
paul@44 739
paul@44 740
    def init_special_attributes(self):
paul@44 741
paul@44 742
        "Add special attributes to the classes for inheritance-related tests."
paul@44 743
paul@44 744
        all_class_attrs = self.importer.all_class_attrs
paul@44 745
paul@44 746
        for name, descendants in self.descendants.items():
paul@44 747
            for descendant in descendants:
paul@44 748
                all_class_attrs[descendant]["#%s" % name] = name
paul@44 749
paul@44 750
        for name in all_class_attrs.keys():
paul@44 751
            all_class_attrs[name]["#%s" % name] = name
paul@44 752
paul@44 753
    def init_usage_index(self):
paul@44 754
paul@44 755
        """
paul@44 756
        Create indexes for module and function attribute usage and for anonymous
paul@44 757
        accesses.
paul@44 758
        """
paul@44 759
paul@44 760
        for module in self.importer.get_modules():
paul@44 761
            for path, assignments in module.attr_usage.items():
paul@44 762
                self.add_usage(assignments, path)
paul@44 763
paul@44 764
        for location, all_attrnames in self.importer.all_attr_accesses.items():
paul@44 765
            for attrnames in all_attrnames:
paul@44 766
                attrname = get_attrnames(attrnames)[-1]
paul@44 767
                access_location = (location, None, attrnames, 0)
paul@107 768
                self.add_usage_term(access_location, ((attrname, False, False),))
paul@44 769
paul@44 770
    def add_usage(self, assignments, path):
paul@44 771
paul@44 772
        """
paul@44 773
        Collect usage from the given 'assignments', adding 'path' details to
paul@44 774
        each record if specified. Add the usage to an index mapping to location
paul@44 775
        information, as well as to an index mapping locations to usages.
paul@44 776
        """
paul@44 777
paul@44 778
        for name, versions in assignments.items():
paul@44 779
            for i, usages in enumerate(versions):
paul@44 780
                location = (path, name, None, i)
paul@44 781
paul@88 782
                for usage in usages:
paul@88 783
                    self.add_usage_term(location, usage)
paul@88 784
paul@88 785
    def add_usage_term(self, location, usage):
paul@44 786
paul@44 787
        """
paul@88 788
        For 'location' and using 'usage' as a description of usage, record
paul@44 789
        in the usage index a mapping from the usage to 'location', and record in
paul@44 790
        the location index a mapping from 'location' to the usage.
paul@44 791
        """
paul@44 792
paul@44 793
        init_item(self.location_index, location, set)
paul@88 794
        self.location_index[location].add(usage)
paul@44 795
paul@44 796
    def init_accessors(self):
paul@44 797
paul@44 798
        "Create indexes for module and function accessor information."
paul@44 799
paul@44 800
        for module in self.importer.get_modules():
paul@44 801
            for path, all_accesses in module.attr_accessors.items():
paul@44 802
                self.add_accessors(all_accesses, path)
paul@44 803
paul@44 804
    def add_accessors(self, all_accesses, path):
paul@44 805
paul@44 806
        """
paul@44 807
        For attribute accesses described by the mapping of 'all_accesses' from
paul@44 808
        name details to accessor details, record the locations of the accessors
paul@44 809
        for each access.
paul@44 810
        """
paul@44 811
paul@44 812
        # Get details for each access combining the given name and attribute.
paul@44 813
paul@44 814
        for (name, attrnames), accesses in all_accesses.items():
paul@44 815
paul@44 816
            # Obtain the usage details using the access information.
paul@44 817
paul@44 818
            for access_number, versions in enumerate(accesses):
paul@44 819
                access_location = (path, name, attrnames, access_number)
paul@44 820
                locations = []
paul@44 821
paul@44 822
                for version in versions:
paul@44 823
                    location = (path, name, None, version)
paul@44 824
                    locations.append(location)
paul@44 825
paul@44 826
                self.access_index[access_location] = locations
paul@44 827
paul@44 828
    def get_accessors_for_access(self, access_location):
paul@44 829
paul@44 830
        "Find a definition providing accessor details, if necessary."
paul@44 831
paul@44 832
        try:
paul@44 833
            return self.access_index[access_location]
paul@44 834
        except KeyError:
paul@44 835
            return [access_location]
paul@44 836
paul@44 837
    def init_accesses(self):
paul@44 838
paul@44 839
        """
paul@501 840
        Check that attributes used in accesses are actually defined on some
paul@501 841
        object. This can be overlooked if unknown attributes are employed in
paul@501 842
        attribute chains.
paul@501 843
paul@44 844
        Initialise collections for accesses involving assignments.
paul@44 845
        """
paul@44 846
paul@44 847
        # For each scope, obtain access details.
paul@44 848
paul@44 849
        for path, all_accesses in self.importer.all_attr_access_modifiers.items():
paul@44 850
paul@44 851
            # For each combination of name and attribute names, obtain
paul@44 852
            # applicable modifiers.
paul@44 853
paul@112 854
            for (name, attrname_str), modifiers in all_accesses.items():
paul@44 855
paul@44 856
                # For each access, determine the name versions affected by
paul@44 857
                # assignments.
paul@44 858
paul@117 859
                for access_number, (assignment, invocation) in enumerate(modifiers):
paul@112 860
paul@44 861
                    if name:
paul@112 862
                        access_location = (path, name, attrname_str, access_number)
paul@44 863
                    else:
paul@112 864
                        access_location = (path, None, attrname_str, 0)
paul@112 865
paul@501 866
                    # Plain name accesses do not employ attributes and are
paul@501 867
                    # ignored.
paul@501 868
paul@502 869
                    if not attrname_str:
paul@501 870
                        continue
paul@501 871
paul@501 872
                    attrnames = get_attrnames(attrname_str)
paul@501 873
paul@501 874
                    # Check the attribute names.
paul@501 875
paul@501 876
                    for attrname in attrnames:
paul@501 877
                        if not attrname in self.all_attrnames:
paul@501 878
                            raise DeduceError("In %s, attribute %s is not defined in the program." % (path, attrname))
paul@501 879
paul@501 880
                    # Now only process assignments and invocations.
paul@501 881
paul@117 882
                    if invocation:
paul@553 883
                        self.reference_invocations[access_location] = invocation
paul@117 884
                        continue
paul@501 885
                    elif not assignment:
paul@501 886
                        continue
paul@501 887
paul@501 888
                    # Associate assignments with usage.
paul@117 889
paul@112 890
                    self.reference_assignments.add(access_location)
paul@71 891
paul@112 892
                    # Assignment occurs for the only attribute.
paul@112 893
paul@112 894
                    if len(attrnames) == 1:
paul@112 895
                        accessor_locations = self.get_accessors_for_access(access_location)
paul@112 896
paul@112 897
                        for location in accessor_locations:
paul@112 898
                            for usage in self.location_index[location]:
paul@88 899
                                init_item(self.assigned_attrs, usage, set)
paul@112 900
                                self.assigned_attrs[usage].add((path, name, attrnames[0]))
paul@112 901
paul@112 902
                    # Assignment occurs for the final attribute.
paul@112 903
paul@112 904
                    else:
paul@112 905
                        usage = ((attrnames[-1], False, False),)
paul@112 906
                        init_item(self.assigned_attrs, usage, set)
paul@112 907
                        self.assigned_attrs[usage].add((path, name, attrnames[-1]))
paul@44 908
paul@44 909
    def init_aliases(self):
paul@44 910
paul@44 911
        "Expand aliases so that alias-based accesses can be resolved."
paul@44 912
paul@44 913
        # Get aliased names with details of their accesses.
paul@44 914
paul@44 915
        for name_path, all_aliases in self.importer.all_aliased_names.items():
paul@44 916
            path, name = name_path.rsplit(".", 1)
paul@44 917
paul@44 918
            # For each version of the name, obtain the access location.
paul@44 919
paul@597 920
            for version, (original_path, original_name, attrnames, access_number) in all_aliases.items():
paul@44 921
                accessor_location = (path, name, None, version)
paul@597 922
                access_location = (original_path, original_name, attrnames, access_number)
paul@44 923
                init_item(self.alias_index, accessor_location, list)
paul@44 924
                self.alias_index[accessor_location].append(access_location)
paul@44 925
paul@44 926
        # Get aliases in terms of non-aliases and accesses.
paul@44 927
paul@44 928
        for accessor_location, access_locations in self.alias_index.items():
paul@44 929
            self.update_aliases(accessor_location, access_locations)
paul@44 930
paul@44 931
    def update_aliases(self, accessor_location, access_locations, visited=None):
paul@44 932
paul@44 933
        """
paul@44 934
        Update the given 'accessor_location' defining an alias, update
paul@44 935
        'access_locations' to refer to non-aliases, following name references
paul@44 936
        via the access index.
paul@44 937
paul@44 938
        If 'visited' is specified, it contains a set of accessor locations (and
paul@44 939
        thus keys to the alias index) that are currently being defined.
paul@44 940
        """
paul@44 941
paul@44 942
        if visited is None:
paul@44 943
            visited = set()
paul@44 944
paul@44 945
        updated_locations = set()
paul@44 946
paul@44 947
        for access_location in access_locations:
paul@44 948
            (path, original_name, attrnames, access_number) = access_location
paul@44 949
paul@44 950
            # Where an alias refers to a name access, obtain the original name
paul@44 951
            # version details.
paul@44 952
paul@44 953
            if attrnames is None:
paul@44 954
paul@44 955
                # For each name version, attempt to determine any accesses that
paul@44 956
                # initialise the name.
paul@44 957
paul@44 958
                for name_accessor_location in self.access_index[access_location]:
paul@44 959
paul@44 960
                    # Already-visited aliases do not contribute details.
paul@44 961
paul@44 962
                    if name_accessor_location in visited:
paul@44 963
                        continue
paul@44 964
paul@44 965
                    visited.add(name_accessor_location)
paul@44 966
paul@44 967
                    name_access_locations = self.alias_index.get(name_accessor_location)
paul@44 968
                    if name_access_locations:
paul@44 969
                        updated_locations.update(self.update_aliases(name_accessor_location, name_access_locations, visited))
paul@44 970
                    else:
paul@44 971
                        updated_locations.add(name_accessor_location)
paul@44 972
paul@44 973
            # Otherwise, record the access details.
paul@44 974
paul@44 975
            else:
paul@44 976
                updated_locations.add(access_location)
paul@44 977
paul@44 978
        self.alias_index[accessor_location] = updated_locations
paul@44 979
        return updated_locations
paul@44 980
paul@44 981
    # Attribute mutation for types.
paul@44 982
paul@44 983
    def modify_mutated_attributes(self):
paul@44 984
paul@44 985
        "Identify known, mutated attributes and change their state."
paul@44 986
paul@44 987
        # Usage-based accesses.
paul@44 988
paul@44 989
        for usage, all_attrnames in self.assigned_attrs.items():
paul@44 990
            if not usage:
paul@44 991
                continue
paul@44 992
paul@112 993
            for path, name, attrname in all_attrnames:
paul@44 994
                class_types = self.get_class_types_for_usage(usage)
paul@44 995
                only_instance_types = set(self.get_instance_types_for_usage(usage)).difference(class_types)
paul@44 996
                module_types = self.get_module_types_for_usage(usage)
paul@44 997
paul@44 998
                # Detect self usage within methods in order to narrow the scope
paul@44 999
                # of the mutation.
paul@44 1000
paul@44 1001
                t = name == "self" and self.constrain_self_reference(path, class_types, only_instance_types)
paul@44 1002
                if t:
paul@44 1003
                    class_types, only_instance_types, module_types, constrained = t
paul@44 1004
                objects = set(class_types).union(only_instance_types).union(module_types)
paul@44 1005
paul@112 1006
                self.mutate_attribute(objects, attrname)
paul@112 1007
paul@112 1008
    def mutate_attribute(self, objects, attrname):
paul@112 1009
paul@112 1010
        "Mutate static 'objects' with the given 'attrname'."
paul@44 1011
paul@44 1012
        for name in objects:
paul@112 1013
            attr = "%s.%s" % (name, attrname)
paul@44 1014
            value = self.importer.get_object(attr)
paul@44 1015
paul@44 1016
            # If the value is None, the attribute is
paul@44 1017
            # inherited and need not be set explicitly on
paul@44 1018
            # the class concerned.
paul@44 1019
paul@44 1020
            if value:
paul@44 1021
                self.modified_attributes[attr] = value
paul@44 1022
                self.importer.set_object(attr, value.as_var())
paul@44 1023
paul@44 1024
    # Simplification of types.
paul@44 1025
paul@69 1026
    def get_most_general_types(self, types):
paul@69 1027
paul@69 1028
        "Return the most general types for the given 'types'."
paul@69 1029
paul@69 1030
        module_types = set()
paul@69 1031
        class_types = set()
paul@69 1032
paul@69 1033
        for type in types:
paul@69 1034
            ref = self.importer.identify(type)
paul@69 1035
            if ref.has_kind("<module>"):
paul@69 1036
                module_types.add(type)
paul@69 1037
            else:
paul@69 1038
                class_types.add(type)
paul@69 1039
paul@69 1040
        types = set(self.get_most_general_module_types(module_types))
paul@69 1041
        types.update(self.get_most_general_class_types(class_types))
paul@69 1042
        return types
paul@69 1043
paul@69 1044
    def get_most_general_class_types(self, class_types):
paul@44 1045
paul@44 1046
        "Return the most general types for the given 'class_types'."
paul@44 1047
paul@44 1048
        class_types = set(class_types)
paul@44 1049
        to_remove = set()
paul@44 1050
paul@44 1051
        for class_type in class_types:
paul@44 1052
            for base in self.importer.classes[class_type]:
paul@44 1053
                base = base.get_origin()
paul@44 1054
                descendants = self.descendants[base]
paul@44 1055
                if base in class_types and descendants.issubset(class_types):
paul@44 1056
                    to_remove.update(descendants)
paul@44 1057
paul@44 1058
        class_types.difference_update(to_remove)
paul@44 1059
        return class_types
paul@44 1060
paul@44 1061
    def get_most_general_module_types(self, module_types):
paul@44 1062
paul@44 1063
        "Return the most general type for the given 'module_types'."
paul@44 1064
paul@44 1065
        # Where all modules are provided, an object would provide the same
paul@44 1066
        # attributes.
paul@44 1067
paul@44 1068
        if len(module_types) == len(self.importer.modules):
paul@44 1069
            return ["__builtins__.object"]
paul@44 1070
        else:
paul@44 1071
            return module_types
paul@44 1072
paul@44 1073
    # More efficient usage-to-type indexing and retrieval.
paul@44 1074
paul@44 1075
    def init_attr_type_indexes(self):
paul@44 1076
paul@44 1077
        "Identify the types that can support each attribute name."
paul@44 1078
paul@44 1079
        self._init_attr_type_index(self.attr_class_types, self.importer.all_class_attrs)
paul@107 1080
        self._init_attr_type_index(self.attr_instance_types, self.importer.all_instance_attrs, True)
paul@107 1081
        self._init_attr_type_index(self.attr_instance_types, self.importer.all_combined_attrs, False)
paul@44 1082
        self._init_attr_type_index(self.attr_module_types, self.importer.all_module_attrs)
paul@44 1083
paul@107 1084
    def _init_attr_type_index(self, attr_types, attrs, assignment=None):
paul@44 1085
paul@44 1086
        """
paul@44 1087
        Initialise the 'attr_types' attribute-to-types mapping using the given
paul@44 1088
        'attrs' type-to-attributes mapping.
paul@44 1089
        """
paul@44 1090
paul@44 1091
        for name, attrnames in attrs.items():
paul@44 1092
            for attrname in attrnames:
paul@107 1093
paul@107 1094
                # Permit general access for certain kinds of object.
paul@107 1095
paul@107 1096
                if assignment is None:
paul@107 1097
                    init_item(attr_types, (attrname, False), set)
paul@107 1098
                    init_item(attr_types, (attrname, True), set)
paul@107 1099
                    attr_types[(attrname, False)].add(name)
paul@107 1100
                    attr_types[(attrname, True)].add(name)
paul@107 1101
paul@107 1102
                # Restrict attribute assignment for instances.
paul@107 1103
paul@107 1104
                else:
paul@107 1105
                    init_item(attr_types, (attrname, assignment), set)
paul@107 1106
                    attr_types[(attrname, assignment)].add(name)
paul@44 1107
paul@88 1108
    def get_class_types_for_usage(self, usage):
paul@88 1109
paul@88 1110
        "Return names of classes supporting the given 'usage'."
paul@88 1111
paul@88 1112
        return self._get_types_for_usage(usage, self.attr_class_types, self.importer.all_class_attrs)
paul@88 1113
paul@88 1114
    def get_instance_types_for_usage(self, usage):
paul@44 1115
paul@44 1116
        """
paul@88 1117
        Return names of classes whose instances support the given 'usage'
paul@44 1118
        (as either class or instance attributes).
paul@44 1119
        """
paul@44 1120
paul@88 1121
        return self._get_types_for_usage(usage, self.attr_instance_types, self.importer.all_combined_attrs)
paul@88 1122
paul@88 1123
    def get_module_types_for_usage(self, usage):
paul@88 1124
paul@88 1125
        "Return names of modules supporting the given 'usage'."
paul@88 1126
paul@88 1127
        return self._get_types_for_usage(usage, self.attr_module_types, self.importer.all_module_attrs)
paul@88 1128
paul@88 1129
    def _get_types_for_usage(self, usage, attr_types, attrs):
paul@44 1130
paul@44 1131
        """
paul@88 1132
        For the given 'usage' representing attribute usage, return types
paul@44 1133
        recorded in the 'attr_types' attribute-to-types mapping that support
paul@44 1134
        such usage, with the given 'attrs' type-to-attributes mapping used to
paul@44 1135
        quickly assess whether a type supports all of the stated attributes.
paul@44 1136
        """
paul@44 1137
paul@44 1138
        # Where no attributes are used, any type would be acceptable.
paul@44 1139
paul@88 1140
        if not usage:
paul@44 1141
            return attrs.keys()
paul@44 1142
paul@107 1143
        keys = []
paul@107 1144
        for attrname, invocation, assignment in usage:
paul@107 1145
            keys.append((attrname, assignment))
paul@107 1146
paul@107 1147
        # Obtain types supporting the first (attribute name, assignment) key...
paul@107 1148
paul@107 1149
        types = set(attr_types.get(keys[0]) or [])
paul@107 1150
paul@107 1151
        for key in keys[1:]:
paul@107 1152
            
paul@44 1153
            # Record types that support all of the other attributes as well.
paul@44 1154
paul@107 1155
            types.intersection_update(attr_types.get(key) or [])
paul@44 1156
paul@44 1157
        return types
paul@44 1158
paul@501 1159
    def init_combined_attribute_index(self):
paul@501 1160
paul@501 1161
        "Initialise a combined index for the detection of invalid attributes."
paul@501 1162
paul@501 1163
        self.all_attrnames = set()
paul@501 1164
        for attrs in (self.importer.all_combined_attrs, self.importer.all_module_attrs):
paul@501 1165
            for name, attrnames in attrs.items():
paul@501 1166
                self.all_attrnames.update(attrnames)
paul@501 1167
paul@44 1168
    # Reference identification.
paul@44 1169
paul@44 1170
    def identify_references(self):
paul@44 1171
paul@44 1172
        "Identify references using usage and name reference information."
paul@44 1173
paul@44 1174
        # Names with associated attribute usage.
paul@44 1175
paul@44 1176
        for location, usages in self.location_index.items():
paul@44 1177
paul@44 1178
            # Obtain attribute usage associated with a name, deducing the nature
paul@44 1179
            # of the name. Obtain types only for branches involving attribute
paul@44 1180
            # usage. (In the absence of usage, any type could be involved, but
paul@44 1181
            # then no accesses exist to require knowledge of the type.)
paul@44 1182
paul@44 1183
            have_usage = False
paul@44 1184
            have_no_usage_branch = False
paul@44 1185
paul@44 1186
            for usage in usages:
paul@44 1187
                if not usage:
paul@44 1188
                    have_no_usage_branch = True
paul@44 1189
                    continue
paul@44 1190
                elif not have_usage:
paul@44 1191
                    self.init_definition_details(location)
paul@44 1192
                    have_usage = True
paul@44 1193
                self.record_types_for_usage(location, usage)
paul@44 1194
paul@44 1195
            # Where some usage occurs, but where branches without usage also
paul@44 1196
            # occur, record the types for those branches anyway.
paul@44 1197
paul@44 1198
            if have_usage and have_no_usage_branch:
paul@44 1199
                self.init_definition_details(location)
paul@44 1200
                self.record_types_for_usage(location, None)
paul@44 1201
paul@44 1202
        # Specific name-based attribute accesses.
paul@44 1203
paul@44 1204
        alias_accesses = set()
paul@44 1205
paul@44 1206
        for access_location, accessor_locations in self.access_index.items():
paul@44 1207
            self.record_types_for_access(access_location, accessor_locations, alias_accesses)
paul@44 1208
paul@44 1209
        # Anonymous references with attribute chains.
paul@44 1210
paul@44 1211
        for location, accesses in self.importer.all_attr_accesses.items():
paul@44 1212
paul@44 1213
            # Get distinct attribute names.
paul@44 1214
paul@44 1215
            all_attrnames = set()
paul@44 1216
paul@44 1217
            for attrnames in accesses:
paul@44 1218
                all_attrnames.update(get_attrnames(attrnames))
paul@44 1219
paul@44 1220
            # Get attribute and accessor details for each attribute name.
paul@44 1221
paul@44 1222
            for attrname in all_attrnames:
paul@44 1223
                access_location = (location, None, attrname, 0)
paul@44 1224
                self.record_types_for_attribute(access_location, attrname)
paul@44 1225
paul@44 1226
        # References via constant/identified objects.
paul@44 1227
paul@44 1228
        for location, name_accesses in self.importer.all_const_accesses.items():
paul@44 1229
paul@44 1230
            # A mapping from the original name and attributes to resolved access
paul@44 1231
            # details.
paul@44 1232
paul@44 1233
            for original_access, access in name_accesses.items():
paul@44 1234
                original_name, original_attrnames = original_access
paul@44 1235
                objpath, ref, attrnames = access
paul@44 1236
paul@44 1237
                # Build an accessor combining the name and attribute names used.
paul@44 1238
paul@44 1239
                original_accessor = tuple([original_name] + original_attrnames.split("."))
paul@44 1240
paul@44 1241
                # Direct accesses to attributes.
paul@44 1242
paul@44 1243
                if not attrnames:
paul@44 1244
paul@44 1245
                    # Build a descriptive location based on the original
paul@44 1246
                    # details, exposing the final attribute name.
paul@44 1247
paul@44 1248
                    oa, attrname = original_accessor[:-1], original_accessor[-1]
paul@44 1249
                    oa = ".".join(oa)
paul@44 1250
paul@44 1251
                    access_location = (location, oa, attrname, 0)
paul@44 1252
                    accessor_location = (location, oa, None, 0)
paul@44 1253
                    self.access_index[access_location] = [accessor_location]
paul@44 1254
paul@44 1255
                    self.init_access_details(access_location)
paul@44 1256
                    self.init_definition_details(accessor_location)
paul@44 1257
paul@44 1258
                    # Obtain a reference for the accessor in order to properly
paul@44 1259
                    # determine its type.
paul@44 1260
paul@44 1261
                    if ref.get_kind() != "<instance>":
paul@44 1262
                        objpath = ref.get_origin()
paul@44 1263
paul@44 1264
                    objpath = objpath.rsplit(".", 1)[0]
paul@44 1265
paul@44 1266
                    # Where the object name conflicts with the module
paul@44 1267
                    # providing it, obtain the module details.
paul@44 1268
paul@44 1269
                    if objpath in self.importer.modules:
paul@44 1270
                        accessor = Reference("<module>", objpath)
paul@44 1271
                    else:
paul@44 1272
                        accessor = self.importer.get_object(objpath)
paul@44 1273
paul@44 1274
                    self.referenced_attrs[access_location] = [(accessor.get_kind(), accessor.get_origin(), ref)]
paul@44 1275
                    self.access_constrained.add(access_location)
paul@44 1276
paul@57 1277
                    class_types, instance_types, module_types = accessor.get_types()
paul@44 1278
                    self.record_reference_types(accessor_location, class_types, instance_types, module_types, True, True)
paul@64 1279
paul@64 1280
                else:
paul@44 1281
paul@64 1282
                    # Build a descriptive location based on the original
paul@64 1283
                    # details, employing the first remaining attribute name.
paul@64 1284
paul@64 1285
                    l = get_attrnames(attrnames)
paul@64 1286
                    attrname = l[0]
paul@44 1287
paul@64 1288
                    oa = original_accessor[:-len(l)]
paul@64 1289
                    oa = ".".join(oa)
paul@44 1290
paul@64 1291
                    access_location = (location, oa, attrnames, 0)
paul@64 1292
                    accessor_location = (location, oa, None, 0)
paul@64 1293
                    self.access_index[access_location] = [accessor_location]
paul@64 1294
paul@64 1295
                    self.init_access_details(access_location)
paul@64 1296
                    self.init_definition_details(accessor_location)
paul@44 1297
paul@64 1298
                    class_types, instance_types, module_types = ref.get_types()
paul@64 1299
paul@64 1300
                    self.identify_reference_attributes(access_location, attrname, class_types, instance_types, module_types, True)
paul@64 1301
                    self.record_reference_types(accessor_location, class_types, instance_types, module_types, True, True)
paul@64 1302
paul@64 1303
                original_location = (location, original_name, original_attrnames, 0)
paul@64 1304
paul@64 1305
                if original_location != access_location:
paul@64 1306
                    self.const_accesses[original_location] = access_location
paul@67 1307
                    self.const_accesses_rev[access_location] = original_location
paul@44 1308
paul@64 1309
        # Aliased name definitions. All aliases with usage will have been
paul@64 1310
        # defined, but they may be refined according to referenced accesses.
paul@44 1311
paul@64 1312
        for accessor_location in self.alias_index.keys():
paul@64 1313
            self.record_types_for_alias(accessor_location)
paul@44 1314
paul@64 1315
        # Update accesses employing aliases.
paul@64 1316
paul@64 1317
        for access_location in alias_accesses:
paul@64 1318
            self.record_types_for_access(access_location, self.access_index[access_location])
paul@44 1319
paul@44 1320
    def constrain_types(self, path, class_types, instance_types, module_types):
paul@44 1321
paul@44 1322
        """
paul@44 1323
        Using the given 'path' to an object, constrain the given 'class_types',
paul@44 1324
        'instance_types' and 'module_types'.
paul@44 1325
paul@44 1326
        Return the class, instance, module types plus whether the types are
paul@44 1327
        constrained to a specific kind of type.
paul@44 1328
        """
paul@44 1329
paul@44 1330
        ref = self.importer.identify(path)
paul@44 1331
        if ref:
paul@44 1332
paul@44 1333
            # Constrain usage suggestions using the identified object.
paul@44 1334
paul@44 1335
            if ref.has_kind("<class>"):
paul@44 1336
                return (
paul@44 1337
                    set(class_types).intersection([ref.get_origin()]), [], [], True
paul@44 1338
                    )
paul@44 1339
            elif ref.has_kind("<module>"):
paul@44 1340
                return (
paul@44 1341
                    [], [], set(module_types).intersection([ref.get_origin()]), True
paul@44 1342
                    )
paul@44 1343
paul@44 1344
        return class_types, instance_types, module_types, False
paul@44 1345
paul@44 1346
    def get_target_types(self, location, usage):
paul@44 1347
paul@44 1348
        """
paul@44 1349
        Return the class, instance and module types constrained for the name at
paul@44 1350
        the given 'location' exhibiting the given 'usage'. Whether the types
paul@44 1351
        have been constrained using contextual information is also indicated,
paul@44 1352
        plus whether the types have been constrained to a specific kind of type.
paul@44 1353
        """
paul@44 1354
paul@44 1355
        unit_path, name, attrnames, version = location
paul@107 1356
        have_assignments = get_assigned_attributes(usage)
paul@44 1357
paul@44 1358
        # Detect any initialised name for the location.
paul@44 1359
paul@44 1360
        if name:
paul@44 1361
            ref = self.get_initialised_name(location)
paul@44 1362
            if ref:
paul@44 1363
                (class_types, only_instance_types, module_types,
paul@57 1364
                    _function_types, _var_types) = separate_types([ref])
paul@107 1365
                return class_types, only_instance_types, module_types, True, have_assignments
paul@44 1366
paul@44 1367
        # Retrieve the recorded types for the usage.
paul@44 1368
paul@44 1369
        class_types = self.get_class_types_for_usage(usage)
paul@44 1370
        only_instance_types = set(self.get_instance_types_for_usage(usage)).difference(class_types)
paul@44 1371
        module_types = self.get_module_types_for_usage(usage)
paul@44 1372
paul@44 1373
        # Merge usage deductions with observations to obtain reference types
paul@44 1374
        # for names involved with attribute accesses.
paul@44 1375
paul@44 1376
        if not name:
paul@107 1377
            return class_types, only_instance_types, module_types, False, have_assignments
paul@44 1378
paul@44 1379
        # Obtain references to known objects.
paul@44 1380
paul@85 1381
        path = get_name_path(unit_path, name)
paul@44 1382
paul@44 1383
        class_types, only_instance_types, module_types, constrained_specific = \
paul@44 1384
            self.constrain_types(path, class_types, only_instance_types, module_types)
paul@44 1385
paul@44 1386
        if constrained_specific:
paul@107 1387
            return class_types, only_instance_types, module_types, constrained_specific, \
paul@107 1388
                constrained_specific or have_assignments
paul@44 1389
paul@44 1390
        # Constrain "self" references.
paul@44 1391
paul@44 1392
        if name == "self":
paul@350 1393
paul@350 1394
            # Test for the class of the method in the deduced types.
paul@350 1395
paul@350 1396
            class_name = self.in_method(unit_path)
paul@350 1397
paul@350 1398
            if class_name and class_name not in class_types and class_name not in only_instance_types:
paul@350 1399
                raise DeduceError("In %s, usage {%s} is not directly supported by class %s or its instances." %
paul@350 1400
                                  (unit_path, encode_usage(usage), class_name))
paul@350 1401
paul@350 1402
            # Constrain the types to the class's hierarchy.
paul@350 1403
paul@44 1404
            t = self.constrain_self_reference(unit_path, class_types, only_instance_types)
paul@44 1405
            if t:
paul@44 1406
                class_types, only_instance_types, module_types, constrained = t
paul@107 1407
                return class_types, only_instance_types, module_types, constrained, have_assignments
paul@107 1408
paul@107 1409
        return class_types, only_instance_types, module_types, False, have_assignments
paul@44 1410
paul@44 1411
    def constrain_self_reference(self, unit_path, class_types, only_instance_types):
paul@44 1412
paul@44 1413
        """
paul@44 1414
        Where the name "self" appears in a method, attempt to constrain the
paul@44 1415
        classes involved.
paul@44 1416
paul@44 1417
        Return the class, instance, module types plus whether the types are
paul@44 1418
        constrained.
paul@44 1419
        """
paul@44 1420
paul@44 1421
        class_name = self.in_method(unit_path)
paul@44 1422
paul@44 1423
        if not class_name:
paul@44 1424
            return None
paul@44 1425
paul@44 1426
        classes = set([class_name])
paul@44 1427
        classes.update(self.get_descendants_for_class(class_name))
paul@44 1428
paul@44 1429
        # Note that only instances will be expected for these references but
paul@44 1430
        # either classes or instances may provide the attributes.
paul@44 1431
paul@44 1432
        return (
paul@44 1433
            set(class_types).intersection(classes),
paul@44 1434
            set(only_instance_types).intersection(classes),
paul@44 1435
            [], True
paul@44 1436
            )
paul@44 1437
paul@44 1438
    def in_method(self, path):
paul@44 1439
paul@44 1440
        "Return whether 'path' refers to a method."
paul@44 1441
paul@44 1442
        class_name, method_name = path.rsplit(".", 1)
paul@274 1443
        return class_name != "__builtins__.core.type" and self.importer.classes.has_key(class_name) and class_name
paul@44 1444
paul@44 1445
    def init_reference_details(self, location):
paul@44 1446
paul@44 1447
        "Initialise reference-related details for 'location'."
paul@44 1448
paul@44 1449
        self.init_definition_details(location)
paul@44 1450
        self.init_access_details(location)
paul@44 1451
paul@44 1452
    def init_definition_details(self, location):
paul@44 1453
paul@44 1454
        "Initialise name definition details for 'location'."
paul@44 1455
paul@44 1456
        self.accessor_class_types[location] = set()
paul@44 1457
        self.accessor_instance_types[location] = set()
paul@44 1458
        self.accessor_module_types[location] = set()
paul@44 1459
        self.provider_class_types[location] = set()
paul@44 1460
        self.provider_instance_types[location] = set()
paul@44 1461
        self.provider_module_types[location] = set()
paul@44 1462
paul@44 1463
    def init_access_details(self, location):
paul@44 1464
paul@44 1465
        "Initialise access details at 'location'."
paul@44 1466
paul@44 1467
        self.referenced_attrs[location] = {}
paul@44 1468
paul@44 1469
    def record_types_for_access(self, access_location, accessor_locations, alias_accesses=None):
paul@44 1470
paul@44 1471
        """
paul@44 1472
        Define types for the 'access_location' associated with the given
paul@44 1473
        'accessor_locations'.
paul@44 1474
        """
paul@44 1475
paul@91 1476
        attrname = get_attrname_from_location(access_location)
paul@91 1477
        if not attrname:
paul@44 1478
            return
paul@44 1479
paul@44 1480
        # Collect all suggested types for the accessors. Accesses may
paul@44 1481
        # require accessors from of a subset of the complete set of types.
paul@44 1482
paul@44 1483
        class_types = set()
paul@44 1484
        module_types = set()
paul@44 1485
        instance_types = set()
paul@44 1486
paul@44 1487
        constrained = True
paul@44 1488
paul@44 1489
        for location in accessor_locations:
paul@44 1490
paul@44 1491
            # Remember accesses employing aliases.
paul@44 1492
paul@44 1493
            if alias_accesses is not None and self.alias_index.has_key(location):
paul@44 1494
                alias_accesses.add(access_location)
paul@44 1495
paul@44 1496
            # Use the type information deduced for names from above.
paul@44 1497
paul@44 1498
            if self.accessor_class_types.has_key(location):
paul@44 1499
                class_types.update(self.accessor_class_types[location])
paul@44 1500
                module_types.update(self.accessor_module_types[location])
paul@44 1501
                instance_types.update(self.accessor_instance_types[location])
paul@44 1502
paul@44 1503
            # Where accesses are associated with assignments but where no
paul@44 1504
            # attribute usage observations have caused such an association,
paul@44 1505
            # the attribute name is considered by itself.
paul@44 1506
paul@44 1507
            else:
paul@44 1508
                self.init_definition_details(location)
paul@107 1509
                self.record_types_for_usage(location, [(attrname, False, False)])
paul@44 1510
paul@67 1511
            constrained = location in self.accessor_constrained and constrained
paul@44 1512
paul@44 1513
        self.init_access_details(access_location)
paul@44 1514
        self.identify_reference_attributes(access_location, attrname, class_types, instance_types, module_types, constrained)
paul@44 1515
paul@44 1516
    def record_types_for_usage(self, accessor_location, usage):
paul@44 1517
paul@44 1518
        """
paul@44 1519
        Record types for the given 'accessor_location' according to the given
paul@44 1520
        'usage' observations which may be None to indicate an absence of usage.
paul@44 1521
        """
paul@44 1522
paul@44 1523
        (class_types,
paul@44 1524
         instance_types,
paul@44 1525
         module_types,
paul@44 1526
         constrained,
paul@44 1527
         constrained_specific) = self.get_target_types(accessor_location, usage)
paul@44 1528
paul@90 1529
        invocations = get_invoked_attributes(usage)
paul@90 1530
paul@107 1531
        self.record_reference_types(accessor_location, class_types, instance_types,
paul@107 1532
            module_types, constrained, constrained_specific, invocations)
paul@44 1533
paul@44 1534
    def record_types_for_attribute(self, access_location, attrname):
paul@44 1535
paul@44 1536
        """
paul@44 1537
        Record types for the 'access_location' employing only the given
paul@44 1538
        'attrname' for type deduction.
paul@44 1539
        """
paul@44 1540
paul@102 1541
        (class_types,
paul@102 1542
         only_instance_types,
paul@102 1543
         module_types) = self.get_types_for_attribute(attrname)
paul@102 1544
paul@102 1545
        self.init_reference_details(access_location)
paul@102 1546
paul@102 1547
        self.identify_reference_attributes(access_location, attrname, class_types, only_instance_types, module_types, False)
paul@102 1548
        self.record_reference_types(access_location, class_types, only_instance_types, module_types, False)
paul@102 1549
paul@102 1550
    def get_types_for_attribute(self, attrname):
paul@102 1551
paul@102 1552
        "Return class, instance-only and module types supporting 'attrname'."
paul@102 1553
paul@107 1554
        usage = ((attrname, False, False),)
paul@44 1555
paul@44 1556
        class_types = self.get_class_types_for_usage(usage)
paul@44 1557
        only_instance_types = set(self.get_instance_types_for_usage(usage)).difference(class_types)
paul@44 1558
        module_types = self.get_module_types_for_usage(usage)
paul@44 1559
paul@102 1560
        return class_types, only_instance_types, module_types
paul@44 1561
paul@44 1562
    def record_types_for_alias(self, accessor_location):
paul@44 1563
paul@44 1564
        """
paul@44 1565
        Define types for the 'accessor_location' not having associated usage.
paul@44 1566
        """
paul@44 1567
paul@44 1568
        have_access = self.provider_class_types.has_key(accessor_location)
paul@44 1569
paul@44 1570
        # With an access, attempt to narrow the existing selection of provider
paul@44 1571
        # types.
paul@44 1572
paul@44 1573
        if have_access:
paul@44 1574
            provider_class_types = self.provider_class_types[accessor_location]
paul@44 1575
            provider_instance_types = self.provider_instance_types[accessor_location]
paul@44 1576
            provider_module_types = self.provider_module_types[accessor_location]
paul@44 1577
paul@44 1578
            # Find details for any corresponding access.
paul@44 1579
paul@44 1580
            all_class_types = set()
paul@44 1581
            all_instance_types = set()
paul@44 1582
            all_module_types = set()
paul@44 1583
paul@44 1584
            for access_location in self.alias_index[accessor_location]:
paul@44 1585
                location, name, attrnames, access_number = access_location
paul@44 1586
paul@44 1587
                # Alias references an attribute access.
paul@44 1588
paul@44 1589
                if attrnames:
paul@44 1590
paul@44 1591
                    # Obtain attribute references for the access.
paul@44 1592
paul@553 1593
                    attrs = []
paul@553 1594
                    for _attrtype, object_type, attr in self.referenced_attrs[access_location]:
paul@553 1595
                        attrs.append(attr)
paul@44 1596
paul@44 1597
                    # Separate the different attribute types.
paul@44 1598
paul@44 1599
                    (class_types, instance_types, module_types,
paul@57 1600
                        function_types, var_types) = separate_types(attrs)
paul@44 1601
paul@44 1602
                    # Where non-accessor types are found, do not attempt to refine
paul@44 1603
                    # the defined accessor types.
paul@44 1604
paul@44 1605
                    if function_types or var_types:
paul@44 1606
                        return
paul@44 1607
paul@44 1608
                    class_types = set(provider_class_types).intersection(class_types)
paul@44 1609
                    instance_types = set(provider_instance_types).intersection(instance_types)
paul@44 1610
                    module_types = set(provider_module_types).intersection(module_types)
paul@44 1611
paul@44 1612
                # Alias references a name, not an access.
paul@44 1613
paul@44 1614
                else:
paul@44 1615
                    # Attempt to refine the types using initialised names.
paul@44 1616
paul@44 1617
                    attr = self.get_initialised_name(access_location)
paul@44 1618
                    if attr:
paul@44 1619
                        (class_types, instance_types, module_types,
paul@57 1620
                            _function_types, _var_types) = separate_types([attr])
paul@44 1621
paul@44 1622
                    # Where no further information is found, do not attempt to
paul@44 1623
                    # refine the defined accessor types.
paul@44 1624
paul@44 1625
                    else:
paul@44 1626
                        return
paul@44 1627
paul@44 1628
                all_class_types.update(class_types)
paul@44 1629
                all_instance_types.update(instance_types)
paul@44 1630
                all_module_types.update(module_types)
paul@44 1631
paul@44 1632
            # Record refined type details for the alias as an accessor.
paul@44 1633
paul@44 1634
            self.init_definition_details(accessor_location)
paul@44 1635
            self.record_reference_types(accessor_location, all_class_types, all_instance_types, all_module_types, False)
paul@44 1636
paul@44 1637
        # Without an access, attempt to identify references for the alias.
paul@44 1638
paul@44 1639
        else:
paul@44 1640
            refs = set()
paul@44 1641
paul@44 1642
            for access_location in self.alias_index[accessor_location]:
paul@64 1643
paul@64 1644
                # Obtain any redefined constant access location.
paul@64 1645
paul@64 1646
                if self.const_accesses.has_key(access_location):
paul@64 1647
                    access_location = self.const_accesses[access_location]
paul@64 1648
paul@44 1649
                location, name, attrnames, access_number = access_location
paul@44 1650
paul@44 1651
                # Alias references an attribute access.
paul@44 1652
paul@44 1653
                if attrnames:
paul@553 1654
                    attrs = []
paul@553 1655
                    for attrtype, object_type, attr in self.referenced_attrs[access_location]:
paul@553 1656
                        attrs.append(attr)
paul@44 1657
                    refs.update(attrs)
paul@44 1658
paul@44 1659
                # Alias references a name, not an access.
paul@44 1660
paul@44 1661
                else:
paul@44 1662
                    attr = self.get_initialised_name(access_location)
paul@44 1663
                    attrs = attr and [attr] or []
paul@44 1664
                    if not attrs and self.provider_class_types.has_key(access_location):
paul@44 1665
                        class_types = self.provider_class_types[access_location]
paul@44 1666
                        instance_types = self.provider_instance_types[access_location]
paul@44 1667
                        module_types = self.provider_module_types[access_location]
paul@57 1668
                        attrs = combine_types(class_types, instance_types, module_types)
paul@44 1669
                    if attrs:
paul@44 1670
                        refs.update(attrs)
paul@44 1671
paul@44 1672
            # Record reference details for the alias separately from accessors.
paul@44 1673
paul@44 1674
            self.referenced_objects[accessor_location] = refs
paul@44 1675
paul@44 1676
    def get_initialised_name(self, access_location):
paul@44 1677
paul@44 1678
        """
paul@44 1679
        Return references for any initialised names at 'access_location', or
paul@44 1680
        None if no such references exist.
paul@44 1681
        """
paul@44 1682
paul@44 1683
        location, name, attrnames, version = access_location
paul@85 1684
        path = get_name_path(location, name)
paul@44 1685
paul@44 1686
        # Use initialiser information, if available.
paul@44 1687
paul@44 1688
        refs = self.importer.all_initialised_names.get(path)
paul@44 1689
        if refs and refs.has_key(version):
paul@44 1690
            return refs[version]
paul@44 1691
        else:
paul@44 1692
            return None
paul@44 1693
paul@44 1694
    def record_reference_types(self, location, class_types, instance_types,
paul@90 1695
        module_types, constrained, constrained_specific=False, invocations=None):
paul@44 1696
paul@44 1697
        """
paul@44 1698
        Associate attribute provider types with the given 'location', consisting
paul@44 1699
        of the given 'class_types', 'instance_types' and 'module_types'.
paul@44 1700
paul@44 1701
        If 'constrained' is indicated, the constrained nature of the accessor is
paul@44 1702
        recorded for the location.
paul@44 1703
paul@44 1704
        If 'constrained_specific' is indicated using a true value, instance types
paul@44 1705
        will not be added to class types to permit access via instances at the
paul@44 1706
        given location. This is only useful where a specific accessor is known
paul@44 1707
        to be a class.
paul@44 1708
paul@105 1709
        If 'invocations' is given, the given attribute names indicate those
paul@105 1710
        which are involved in invocations. Such invocations, if involving
paul@105 1711
        functions, will employ those functions as bound methods and will
paul@105 1712
        therefore not support classes as accessors, only instances of such
paul@105 1713
        classes.
paul@105 1714
paul@44 1715
        Note that the specified types only indicate the provider types for
paul@44 1716
        attributes, whereas the recorded accessor types indicate the possible
paul@44 1717
        types of the actual objects used to access attributes.
paul@44 1718
        """
paul@44 1719
paul@44 1720
        # Update the type details for the location.
paul@44 1721
paul@44 1722
        self.provider_class_types[location].update(class_types)
paul@44 1723
        self.provider_instance_types[location].update(instance_types)
paul@44 1724
        self.provider_module_types[location].update(module_types)
paul@44 1725
paul@44 1726
        # Class types support classes and instances as accessors.
paul@44 1727
        # Instance-only and module types support only their own kinds as
paul@44 1728
        # accessors.
paul@44 1729
paul@90 1730
        path, name, version, attrnames = location
paul@90 1731
paul@90 1732
        if invocations:
paul@90 1733
            class_only_types = self.filter_for_invocations(class_types, invocations)
paul@90 1734
        else:
paul@90 1735
            class_only_types = class_types
paul@90 1736
paul@44 1737
        # However, the nature of accessors can be further determined.
paul@44 1738
        # Any self variable may only refer to an instance.
paul@44 1739
paul@44 1740
        if name != "self" or not self.in_method(path):
paul@90 1741
            self.accessor_class_types[location].update(class_only_types)
paul@44 1742
paul@44 1743
        if not constrained_specific:
paul@44 1744
            self.accessor_instance_types[location].update(class_types)
paul@44 1745
paul@44 1746
        self.accessor_instance_types[location].update(instance_types)
paul@44 1747
paul@44 1748
        if name != "self" or not self.in_method(path):
paul@44 1749
            self.accessor_module_types[location].update(module_types)
paul@44 1750
paul@44 1751
        if constrained:
paul@67 1752
            self.accessor_constrained.add(location)
paul@44 1753
paul@90 1754
    def filter_for_invocations(self, class_types, attrnames):
paul@90 1755
paul@90 1756
        """
paul@90 1757
        From the given 'class_types', identify methods for the given
paul@90 1758
        'attrnames' that are being invoked, returning a filtered collection of
paul@90 1759
        class types.
paul@553 1760
paul@553 1761
        This method may be used to remove class types from consideration where
paul@553 1762
        their attributes are methods that are directly invoked: method
paul@553 1763
        invocations must involve instance accessors.
paul@90 1764
        """
paul@90 1765
paul@90 1766
        to_filter = set()
paul@90 1767
paul@90 1768
        for class_type in class_types:
paul@90 1769
            for attrname in attrnames:
paul@553 1770
paul@553 1771
                # Attempt to obtain a class attribute of the given name. This
paul@553 1772
                # may return an attribute provided by an ancestor class.
paul@553 1773
paul@90 1774
                ref = self.importer.get_class_attribute(class_type, attrname)
paul@90 1775
                parent_class = ref and ref.parent()
paul@90 1776
paul@553 1777
                # If such an attribute is a method and would be available on
paul@553 1778
                # the given class, record the class for filtering.
paul@553 1779
paul@90 1780
                if ref and ref.has_kind("<function>") and (
paul@90 1781
                   parent_class == class_type or
paul@90 1782
                   class_type in self.descendants[parent_class]):
paul@90 1783
paul@90 1784
                    to_filter.add(class_type)
paul@90 1785
                    break
paul@90 1786
paul@90 1787
        return set(class_types).difference(to_filter)
paul@90 1788
paul@44 1789
    def identify_reference_attributes(self, location, attrname, class_types, instance_types, module_types, constrained):
paul@44 1790
paul@44 1791
        """
paul@44 1792
        Identify reference attributes, associating them with the given
paul@44 1793
        'location', identifying the given 'attrname', employing the given
paul@44 1794
        'class_types', 'instance_types' and 'module_types'.
paul@44 1795
paul@44 1796
        If 'constrained' is indicated, the constrained nature of the access is
paul@44 1797
        recorded for the location.
paul@44 1798
        """
paul@44 1799
paul@44 1800
        # Record the referenced objects.
paul@44 1801
paul@44 1802
        self.referenced_attrs[location] = \
paul@555 1803
            self._identify_reference_attribute(location, attrname, class_types, instance_types, module_types)
paul@44 1804
paul@44 1805
        if constrained:
paul@44 1806
            self.access_constrained.add(location)
paul@44 1807
paul@555 1808
    def _identify_reference_attribute(self, location, attrname, class_types, instance_types, module_types):
paul@44 1809
paul@44 1810
        """
paul@555 1811
        Identify the reference attribute at the given access 'location', using
paul@555 1812
        the given 'attrname', and employing the given 'class_types',
paul@555 1813
        'instance_types' and 'module_types'.
paul@44 1814
        """
paul@44 1815
paul@44 1816
        attrs = set()
paul@44 1817
paul@44 1818
        # The class types expose class attributes either directly or via
paul@44 1819
        # instances.
paul@44 1820
paul@44 1821
        for object_type in class_types:
paul@44 1822
            ref = self.importer.get_class_attribute(object_type, attrname)
paul@555 1823
            if ref and self.is_compatible_callable(location, object_type, ref):
paul@44 1824
                attrs.add(("<class>", object_type, ref))
paul@44 1825
paul@44 1826
            # Add any distinct instance attributes that would be provided
paul@44 1827
            # by instances also providing indirect class attribute access.
paul@44 1828
paul@44 1829
            for ref in self.importer.get_instance_attributes(object_type, attrname):
paul@555 1830
                if self.is_compatible_callable(location, object_type, ref):
paul@555 1831
                    attrs.add(("<instance>", object_type, ref))
paul@44 1832
paul@44 1833
        # The instance-only types expose instance attributes, but although
paul@44 1834
        # classes are excluded as potential accessors (since they do not provide
paul@44 1835
        # the instance attributes), the class types may still provide some
paul@44 1836
        # attributes.
paul@44 1837
paul@44 1838
        for object_type in instance_types:
paul@44 1839
            instance_attrs = self.importer.get_instance_attributes(object_type, attrname)
paul@44 1840
paul@44 1841
            if instance_attrs:
paul@44 1842
                for ref in instance_attrs:
paul@555 1843
                    if self.is_compatible_callable(location, object_type, ref):
paul@555 1844
                        attrs.add(("<instance>", object_type, ref))
paul@44 1845
            else:
paul@44 1846
                ref = self.importer.get_class_attribute(object_type, attrname)
paul@555 1847
                if ref and self.is_compatible_callable(location, object_type, ref):
paul@44 1848
                    attrs.add(("<class>", object_type, ref))
paul@44 1849
paul@44 1850
        # Module types expose module attributes for module accessors.
paul@44 1851
paul@44 1852
        for object_type in module_types:
paul@44 1853
            ref = self.importer.get_module_attribute(object_type, attrname)
paul@555 1854
            if ref and self.is_compatible_callable(location, object_type, ref):
paul@44 1855
                attrs.add(("<module>", object_type, ref))
paul@44 1856
paul@44 1857
        return attrs
paul@44 1858
paul@555 1859
    def is_compatible_callable(self, location, object_type, ref):
paul@555 1860
paul@555 1861
        """
paul@555 1862
        Return whether any invocation at 'location' involving an attribute of
paul@555 1863
        'object_type' identified by 'ref' is compatible with any arguments used.
paul@555 1864
        """
paul@555 1865
paul@557 1866
        invocation = self.reference_invocations.get(location)
paul@557 1867
        if invocation is None:
paul@555 1868
            return True
paul@555 1869
paul@555 1870
        objpath = ref.get_origin()
paul@555 1871
        if not objpath:
paul@555 1872
            return True
paul@555 1873
paul@555 1874
        parameters = self.importer.function_parameters.get(objpath)
paul@555 1875
        if not parameters:
paul@555 1876
            return True
paul@555 1877
paul@555 1878
        defaults = self.importer.function_defaults.get(objpath)
paul@557 1879
        arguments, keywords = invocation
paul@557 1880
        names = set(parameters)
paul@555 1881
paul@555 1882
        # Determine whether the specified arguments are
paul@555 1883
        # compatible with the callable signature.
paul@555 1884
paul@555 1885
        if arguments >= len(parameters) - len(defaults) and \
paul@557 1886
           arguments <= len(parameters) and \
paul@557 1887
           names.issuperset(keywords):
paul@555 1888
paul@555 1889
            return True
paul@555 1890
        else:
paul@555 1891
            init_item(self.reference_invocations_unsuitable, location, set)
paul@555 1892
            self.reference_invocations_unsuitable[location].add(ref)
paul@555 1893
            return False
paul@555 1894
paul@553 1895
    # Attribute access plan formulation.
paul@553 1896
paul@67 1897
    class_tests = (
paul@237 1898
        ("guarded", "specific", "type"),
paul@237 1899
        ("guarded", "common", "type"),
paul@237 1900
        ("test", "specific", "type"),
paul@237 1901
        ("test", "common", "type"),
paul@67 1902
        )
paul@67 1903
paul@67 1904
    def get_access_plan(self, location):
paul@65 1905
paul@77 1906
        """
paul@77 1907
        Return details of the access at the given 'location'. The details are as
paul@77 1908
        follows:
paul@77 1909
paul@77 1910
         * the initial accessor (from which accesses will be performed if no
paul@77 1911
           computed static accessor is found)
paul@77 1912
         * details of any test required on the initial accessor
paul@77 1913
         * details of any type employed by the test
paul@77 1914
         * any static accessor (from which accesses will be performed in
paul@77 1915
           preference to the initial accessor)
paul@77 1916
         * attributes needing to be traversed from the base that yield
paul@77 1917
           unambiguous objects
paul@98 1918
         * access modes for each of the unambiguously-traversed attributes
paul@77 1919
         * remaining attributes needing to be tested and traversed
paul@77 1920
         * details of the context
paul@102 1921
         * any test to apply to the context
paul@77 1922
         * the method of obtaining the final attribute
paul@77 1923
         * any static final attribute
paul@325 1924
         * the kinds of objects providing the final attribute
paul@77 1925
        """
paul@65 1926
paul@256 1927
        const_access = self.const_accesses_rev.get(location)
paul@65 1928
paul@75 1929
        path, name, attrnames, version = location
paul@75 1930
        remaining = attrnames.split(".")
paul@75 1931
        attrname = remaining[0]
paul@65 1932
paul@67 1933
        # Obtain reference and accessor information, retaining also distinct
paul@67 1934
        # provider kind details.
paul@65 1935
paul@65 1936
        attrs = []
paul@65 1937
        objtypes = []
paul@67 1938
        provider_kinds = set()
paul@67 1939
paul@65 1940
        for attrtype, objtype, attr in self.referenced_attrs[location]:
paul@65 1941
            attrs.append(attr)
paul@65 1942
            objtypes.append(objtype)
paul@67 1943
            provider_kinds.add(attrtype)
paul@67 1944
paul@67 1945
        # Obtain accessor type and kind information.
paul@67 1946
paul@67 1947
        accessor_types = self.reference_all_accessor_types[location]
paul@67 1948
        accessor_general_types = self.reference_all_accessor_general_types[location]
paul@67 1949
        accessor_kinds = get_kinds(accessor_general_types)
paul@67 1950
paul@67 1951
        # Determine any guard or test requirements.
paul@67 1952
paul@67 1953
        constrained = location in self.access_constrained
paul@70 1954
        test = self.reference_test_types[location]
paul@77 1955
        test_type = self.reference_test_accessor_type.get(location)
paul@67 1956
paul@67 1957
        # Determine the accessor and provider properties.
paul@67 1958
paul@67 1959
        class_accessor = "<class>" in accessor_kinds
paul@67 1960
        module_accessor = "<module>" in accessor_kinds
paul@67 1961
        instance_accessor = "<instance>" in accessor_kinds
paul@67 1962
        provided_by_class = "<class>" in provider_kinds
paul@67 1963
        provided_by_instance = "<instance>" in provider_kinds
paul@67 1964
paul@74 1965
        # Determine how attributes may be accessed relative to the accessor.
paul@74 1966
paul@74 1967
        object_relative = class_accessor or module_accessor or provided_by_instance
paul@74 1968
        class_relative = instance_accessor and provided_by_class
paul@74 1969
paul@67 1970
        # Identify the last static attribute for context acquisition.
paul@67 1971
paul@67 1972
        base = None
paul@67 1973
        dynamic_base = None
paul@67 1974
paul@67 1975
        # Constant accesses have static accessors.
paul@65 1976
paul@65 1977
        if const_access:
paul@65 1978
            base = len(objtypes) == 1 and first(objtypes)
paul@67 1979
paul@263 1980
        # Name-based accesses.
paul@67 1981
paul@213 1982
        elif name:
paul@65 1983
            ref = self.importer.identify("%s.%s" % (path, name))
paul@263 1984
paul@263 1985
            # Constant accessors are static.
paul@263 1986
paul@263 1987
            if ref and ref.static():
paul@65 1988
                base = ref.get_origin()
paul@65 1989
paul@70 1990
            # Usage of previously-generated guard and test details.
paul@70 1991
paul@237 1992
            elif test[:2] == ("constrained", "specific"):
paul@67 1993
                ref = first(accessor_types)
paul@67 1994
paul@237 1995
            elif test[:2] == ("constrained", "common"):
paul@67 1996
                ref = first(accessor_general_types)
paul@67 1997
paul@237 1998
            elif test[:2] == ("guarded", "specific"):
paul@67 1999
                ref = first(accessor_types)
paul@67 2000
paul@237 2001
            elif test[:2] == ("guarded", "common"):
paul@67 2002
                ref = first(accessor_general_types)
paul@67 2003
paul@70 2004
            # For attribute-based tests, tentatively identify a dynamic base.
paul@70 2005
            # Such tests allow single or multiple kinds of a type.
paul@70 2006
paul@237 2007
            elif test[0] == "test" and test[1] in ("common", "specific"):
paul@77 2008
                dynamic_base = test_type
paul@67 2009
paul@67 2010
            # Static accessors.
paul@67 2011
paul@70 2012
            if not base and test in self.class_tests:
paul@70 2013
                base = ref and ref.get_origin() or dynamic_base
paul@70 2014
paul@70 2015
            # Accessors that are not static but whose nature is determined.
paul@70 2016
paul@70 2017
            elif not base and ref:
paul@67 2018
                dynamic_base = ref.get_origin()
paul@67 2019
paul@102 2020
        # Determine initial accessor details.
paul@102 2021
paul@102 2022
        accessor = base or dynamic_base
paul@102 2023
        accessor_kind = len(accessor_kinds) == 1 and first(accessor_kinds) or None
paul@102 2024
        provider_kind = len(provider_kinds) == 1 and first(provider_kinds) or None
paul@102 2025
paul@102 2026
        # Traverse remaining attributes.
paul@102 2027
paul@65 2028
        traversed = []
paul@96 2029
        traversal_modes = []
paul@65 2030
paul@108 2031
        while len(attrs) == 1 and not first(attrs).has_kind("<var>"):
paul@65 2032
            attr = first(attrs)
paul@65 2033
paul@65 2034
            traversed.append(attrname)
paul@96 2035
            traversal_modes.append(accessor_kind == provider_kind and "object" or "class")
paul@96 2036
paul@102 2037
            # Consume attribute names providing unambiguous attributes.
paul@102 2038
paul@75 2039
            del remaining[0]
paul@75 2040
paul@75 2041
            if not remaining:
paul@65 2042
                break
paul@65 2043
paul@67 2044
            # Update the last static attribute.
paul@67 2045
paul@65 2046
            if attr.static():
paul@65 2047
                base = attr.get_origin()
paul@65 2048
                traversed = []
paul@96 2049
                traversal_modes = []
paul@65 2050
paul@102 2051
            # Get the access details.
paul@67 2052
paul@75 2053
            attrname = remaining[0]
paul@102 2054
            accessor = attr.get_origin()
paul@102 2055
            accessor_kind = attr.get_kind()
paul@102 2056
            provider_kind = self.importer.get_attribute_provider(attr, attrname)
paul@102 2057
            accessor_kinds = [accessor_kind]
paul@102 2058
            provider_kinds = [provider_kind]
paul@102 2059
paul@102 2060
            # Get the next attribute.
paul@102 2061
paul@65 2062
            attrs = self.importer.get_attributes(attr, attrname)
paul@67 2063
paul@67 2064
        # Where many attributes are suggested, no single attribute identity can
paul@67 2065
        # be loaded.
paul@67 2066
paul@65 2067
        else:
paul@65 2068
            attr = None
paul@65 2069
paul@67 2070
        # Determine the method of access.
paul@67 2071
paul@256 2072
        is_assignment = location in self.reference_assignments or const_access in self.reference_assignments
paul@256 2073
        is_invocation = location in self.reference_invocations or const_access in self.reference_invocations
paul@98 2074
paul@71 2075
        # Identified attribute that must be accessed via its parent.
paul@71 2076
paul@98 2077
        if attr and attr.get_name() and is_assignment:
paul@98 2078
            final_method = "static-assign"; origin = attr.get_name()
paul@71 2079
paul@67 2080
        # Static, identified attribute.
paul@67 2081
paul@71 2082
        elif attr and attr.static():
paul@117 2083
            final_method = is_assignment and "static-assign" or \
paul@117 2084
                           is_invocation and "static-invoke" or \
paul@117 2085
                           "static"
paul@98 2086
            origin = attr.final()
paul@94 2087
paul@94 2088
        # All other methods of access involve traversal.
paul@94 2089
paul@94 2090
        else:
paul@587 2091
            final_method = is_assignment and "assign" or \
paul@587 2092
                           is_invocation and "access-invoke" or \
paul@587 2093
                           "access"
paul@98 2094
            origin = None
paul@67 2095
paul@93 2096
        # First attribute accessed at a known position via the accessor.
paul@67 2097
paul@495 2098
        # Static bases support object-relative accesses only.
paul@495 2099
paul@495 2100
        if base:
paul@495 2101
            first_method = "relative-object"
paul@495 2102
paul@495 2103
        # Dynamic bases support either object- or class-relative accesses.
paul@495 2104
paul@495 2105
        elif dynamic_base:
paul@94 2106
            first_method = "relative" + (object_relative and "-object" or "") + \
paul@94 2107
                                        (class_relative and "-class" or "")
paul@67 2108
paul@67 2109
        # The fallback case is always run-time testing and access.
paul@67 2110
paul@67 2111
        else:
paul@94 2112
            first_method = "check" + (object_relative and "-object" or "") + \
paul@94 2113
                                     (class_relative and "-class" or "")
paul@67 2114
paul@102 2115
        # Determine whether an unbound method is being accessed via an instance,
paul@102 2116
        # requiring a context test.
paul@102 2117
paul@102 2118
        context_test = "ignore"
paul@102 2119
paul@102 2120
        # Assignments do not employ the context.
paul@102 2121
paul@102 2122
        if is_assignment:
paul@102 2123
            pass
paul@102 2124
paul@102 2125
        # Obtain a selection of possible attributes if no unambiguous attribute
paul@102 2126
        # was identified.
paul@102 2127
paul@102 2128
        elif not attr:
paul@102 2129
paul@102 2130
            # Use previously-deduced attributes for a simple ambiguous access.
paul@102 2131
            # Otherwise, use the final attribute name to obtain possible
paul@102 2132
            # attributes.
paul@102 2133
paul@102 2134
            if len(remaining) > 1:
paul@102 2135
                attrname = remaining[-1]
paul@102 2136
paul@102 2137
                (class_types,
paul@102 2138
                 only_instance_types,
paul@102 2139
                 module_types) = self.get_types_for_attribute(attrname)
paul@102 2140
paul@212 2141
                accessor_kinds = set()
paul@212 2142
                provider_kinds = set()
paul@102 2143
paul@102 2144
                if class_types:
paul@212 2145
                    accessor_kinds.add("<class>")
paul@212 2146
                    accessor_kinds.add("<instance>")
paul@212 2147
                    provider_kinds.add("<class>")
paul@102 2148
                if only_instance_types:
paul@212 2149
                    accessor_kinds.add("<instance>")
paul@212 2150
                    provider_kinds.add("<instance>")
paul@102 2151
                if module_types:
paul@212 2152
                    accessor_kinds.add("<module>")
paul@212 2153
                    provider_kinds.add("<module>")
paul@102 2154
paul@102 2155
                attrs = set()
paul@102 2156
                for type in combine_types(class_types, only_instance_types, module_types):
paul@102 2157
                    attrs.update(self.importer.get_attributes(type, attrname))
paul@102 2158
paul@102 2159
            always_unbound = True
paul@102 2160
            have_function = False
paul@102 2161
            have_var = False
paul@102 2162
paul@102 2163
            # Determine whether all attributes are unbound methods and whether
paul@102 2164
            # functions or unidentified attributes occur.
paul@102 2165
paul@102 2166
            for attr in attrs:
paul@102 2167
                always_unbound = always_unbound and attr.has_kind("<function>") and attr.name_parent() == attr.parent()
paul@102 2168
                have_function = have_function or attr.has_kind("<function>")
paul@102 2169
                have_var = have_var or attr.has_kind("<var>")
paul@102 2170
paul@102 2171
            # Test for class-via-instance accesses.
paul@102 2172
paul@102 2173
            if accessor_kind == "<instance>" and \
paul@102 2174
               provider_kind == "<class>":
paul@102 2175
paul@102 2176
                if always_unbound:
paul@102 2177
                    context_test = "replace"
paul@102 2178
                else:
paul@102 2179
                    context_test = "test"
paul@102 2180
paul@102 2181
            # Test for the presence of class-via-instance accesses.
paul@102 2182
paul@102 2183
            elif "<instance>" in accessor_kinds and \
paul@102 2184
                 "<class>" in provider_kinds and \
paul@102 2185
                 (have_function or have_var):
paul@102 2186
paul@102 2187
                context_test = "test"
paul@102 2188
paul@102 2189
        # With an unambiguous attribute, determine whether a test is needed.
paul@102 2190
paul@102 2191
        elif accessor_kind == "<instance>" and \
paul@102 2192
             provider_kind == "<class>" and \
paul@102 2193
             (attr.has_kind("<var>") or
paul@102 2194
              attr.has_kind("<function>") and
paul@102 2195
              attr.name_parent() == attr.parent()):
paul@102 2196
paul@102 2197
            if attr.has_kind("<var>"):
paul@102 2198
                context_test = "test"
paul@102 2199
            else:
paul@102 2200
                context_test = "replace"
paul@102 2201
paul@102 2202
        # With an unambiguous attribute with ambiguity in the access method,
paul@102 2203
        # generate a test.
paul@102 2204
paul@102 2205
        elif "<instance>" in accessor_kinds and \
paul@102 2206
             "<class>" in provider_kinds and \
paul@102 2207
             (attr.has_kind("<var>") or
paul@102 2208
              attr.has_kind("<function>") and
paul@102 2209
              attr.name_parent() == attr.parent()):
paul@102 2210
paul@102 2211
            context_test = "test"
paul@102 2212
paul@75 2213
        # Determine the nature of the context.
paul@75 2214
paul@102 2215
        context = context_test == "ignore" and "unset" or \
paul@100 2216
                  len(traversed + remaining) == 1 and \
paul@100 2217
                      (base and "base" or "original-accessor") or \
paul@100 2218
                  "final-accessor"
paul@77 2219
paul@234 2220
        return name, test, test_type, base, \
paul@234 2221
               traversed, traversal_modes, remaining, \
paul@234 2222
               context, context_test, \
paul@234 2223
               first_method, final_method, \
paul@234 2224
               origin, accessor_kinds
paul@65 2225
paul@44 2226
# vim: tabstop=4 expandtab shiftwidth=4