#!/usr/bin/env python  """ Module abstractions.  Copyright (C) 2007, 2008, 2009, 2010, 2011, 2012, 2013,               2014, 2015, 2016 Paul Boddie <paul@boddie.org.uk>  This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 3 of the License, or (at your option) any later version.  This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more details.  You should have received a copy of the GNU General Public License along with this program.  If not, see <http://www.gnu.org/licenses/>. """  from common import init_item, remove_items, CommonModule from encoders import decode_modifier_term, decode_usage, encode_modifiers, encode_usage from referencing import decode_reference, Reference from results import ResolvedNameRef import sys  class BasicModule(CommonModule):      "The basic module information."      def __init__(self, name, importer):         CommonModule.__init__(self, name, importer)          # Import details, primarily for cache output.          self.imports = set()         self.required = set()         self.deferred = []          # Global name information.          self.objects = {}         self.special = {}          # Class relationships.          self.classes = {}          # Attributes.          self.class_attrs = {}         self.instance_attrs = {}         self.instance_attr_constants = {}         self.module_attrs = set()          # Names used in each namespace.          self.names_used = {}          # Function details.          self.function_parameters = {}         self.function_defaults = {}         self.function_locals = {}         self.scope_globals = {}          # Invocation details.          self.function_targets = {}         self.function_arguments = {}          # Attribute usage at module and function levels.          self.attr_usage = {}         self.name_initialisers = {}          # General attribute access expressions.          self.attr_accesses = {}         self.const_accesses = {}          # Attribute accessor definition details.          self.attr_accessors = {}          # Assignment details for accesses.          self.attr_access_modifiers = {}          # Name resolution details.          self.name_references = {} # references to globals          # Initialisation-related details.          self.initialised_names = {}         self.aliased_names = {}      def __repr__(self):         return "BasicModule(%r, %r)" % (self.name, self.importer)      # Derived information methods.      def propagate(self):          "Finalise and propagate module information."          self.propagate_attrs()         self.propagate_name_references()         self.propagate_attr_accesses()         self.propagate_constants()      def unpropagate(self):          """         Retract information from the importer including information about this         module derived by the importer.         """          del self.importer.all_module_attrs[self.name]          for name in self.classes.keys():             del self.importer.classes[name]             del self.importer.all_class_attrs[name]             del self.importer.all_instance_attrs[name]             del self.importer.all_instance_attr_constants[name]              for name, bases in self.classes.items():                 for base in bases:                      # Get the identity of the class from the reference.                      base = base.get_origin()                      try:                         self.importer.subclasses[base].remove(name)                     except (KeyError, ValueError):                         pass          remove_items(self.importer.all_name_references, self.name_references)         remove_items(self.importer.all_initialised_names, self.initialised_names)         remove_items(self.importer.all_aliased_names, self.aliased_names)         remove_items(self.importer.all_attr_accesses, self.attr_accesses)         remove_items(self.importer.all_const_accesses, self.const_accesses)         remove_items(self.importer.all_attr_access_modifiers, self.attr_access_modifiers)         remove_items(self.importer.all_constants, self.constants)         remove_items(self.importer.all_constant_values, self.constant_values)          # Remove this module's objects from the importer. Objects are         # automatically propagated when defined.          ref = self.importer.objects.get(self.name)         if ref and ref.has_kind("<module>"):             del self.importer.objects[self.name]          for name, ref in self.objects.items():             if not ref.has_kind("<module>"):                 del self.importer.objects[name]      def collect(self):          "Collect removed objects."          for name, ref in self.objects.items():             if not self.importer.objects.has_key(ref.get_origin()) and self.importer.objects.has_key(name):                 del self.importer.objects[name]      def propagate_attrs(self):          "Derive attributes from the class and module member details."          # Initialise class attribute records for all classes.          for name in self.classes.keys():             self.importer.all_class_attrs[name] = self.class_attrs[name] = {}          # Separate the objects into module and class attributes.          for name in self.objects.keys():             if "." in name:                 parent, attrname = name.rsplit(".", 1)                 if self.classes.has_key(parent):                     self.class_attrs[parent][attrname] = name                 elif parent == self.name:                     self.module_attrs.add(attrname)          # Propagate the module attributes.          self.importer.all_module_attrs[self.name] = self.module_attrs      def propagate_name_references(self):          "Propagate name references for the module."          self.importer.all_initialised_names.update(self.initialised_names)         self.importer.all_aliased_names.update(self.aliased_names)      def propagate_attr_accesses(self):          "Propagate attribute accesses for the module."          self.importer.all_attr_accesses.update(self.attr_accesses)         self.importer.all_const_accesses.update(self.const_accesses)         self.importer.all_attr_access_modifiers.update(self.attr_access_modifiers)      def propagate_constants(self):          "Propagate constant values and aliases for the module."          self.importer.all_constants.update(self.constants)         self.importer.all_constant_values.update(self.constant_values)          for name in self.classes.keys():             self.importer.all_instance_attrs[name] = self.instance_attrs.get(name) or {}             self.importer.all_instance_attr_constants[name] = self.instance_attr_constants.get(name) or {}      def set_object(self, name, value=None):          "Set an object with the given 'name' and the given 'value'."          # Decode any string value, with a new reference being returned even         # given a provided reference.          ref = decode_reference(value, name)         self.add_deferred(ref)         self._set_object(name, ref)      def _set_object(self, name, ref):          # Determine how the object properties will be defined.          multiple = self.objects.has_key(name) and self.objects[name].get_kind() != ref.get_kind()         self.importer.objects[name] = self.objects[name] = multiple and ref.as_var() or ref      def queue_module(self, name, required=False):          """         Queue the module with the given 'name'. If 'required' is true (it is         false by default), indicate that the module is required in the final         program.         """          self.importer.queue_module(name, self, required)         if required:             self.required.add(name)         self.imports.add(name)  class InspectionNaming:      "Name operations related to inspection."      # Module-relative naming.      def is_global(self, name):          """         Return whether 'name' is registered as a global in the current         namespace.         """          path = self.get_namespace_path()         return name in self.scope_globals.get(path, [])      def get_global(self, name):          """         Get the global of the given 'name' from this module, returning a         reference incorporating the original definition details.         """          path = self.get_global_path(name)         return self.objects.get(path)      # Name definition discovery.      def get_global_or_builtin(self, name):          """         Return a reference for the given 'name' found in this module or in the         __builtins__.         """          return self.get_global(name) or self.get_builtin(name)      def get_builtin(self, name):          "Return a reference to the built-in with the given 'name'."          self.queue_module("__builtins__")         ref = Reference("<depends>", "__builtins__.%s" % name)         self.deferred.append(ref)         return ref      def get_builtin_class(self, name):          "Return a reference to the actual object providing 'name'."          # NOTE: This makes assumptions about the __builtins__ structure.          module_name = "__builtins__.%s" % name         if self.name != module_name:             self.queue_module(module_name, True)         return Reference("<class>", "__builtins__.%s.%s" % (name, name))      def get_object(self, path):          """         Get the details of an object with the given 'path'. Where the object         cannot be resolved, an unresolved reference is returned.         """          if self.objects.has_key(path):             return self.objects[path]         else:             ref = Reference("<depends>", path)             self.deferred.append(ref)             return ref      def import_name_from_module(self, name, module_name):          "Import 'name' from the module having the given 'module_name'."          if module_name != self.name:             self.queue_module(module_name)         return Reference("<depends>", "%s.%s" % (module_name, name))      def add_deferred(self, ref):          "Record 'ref' as a deferred reference."          if ref.has_kind("<depends>"):             self.deferred.append(ref)  class CachedModule(BasicModule):      "A cached module."      def __repr__(self):         return "CachedModule(%r, %r)" % (self.name, self.importer)      def set_object(self, name, value=None):          "Set an object with the given 'name' and the given 'value'."          # Decode any string value, with a new reference being returned even         # given a provided reference.          ref = decode_reference(value, name)         self._set_object(name, ref)      def to_cache(self, filename):          "Not actually writing the module back to 'filename'."          pass      def from_cache(self, filename):          """         Read a module's details from the file with the given 'filename' as         described in the to_cache method of InspectedModule.         """          f = open(filename)         try:             self.filename = f.readline().rstrip()              f.readline() # (empty line)              self._get_imports(f)             self._get_members(f)             self._get_class_relationships(f)             self._get_instance_attrs(f)             self._get_instance_attr_constants(f)             self.from_lines(f, self.names_used)     # "names used:"             self._get_name_references(f)             self._get_initialised_names(f)             self._get_aliased_names(f)             self._get_function_parameters(f)             self._get_function_defaults(f)             self._get_function_locals(f)             self.from_lines(f, self.scope_globals)  # "scope globals:"             self._get_function_targets(f)             self._get_function_arguments(f)             self._get_attribute_usage(f)             self._get_attr_accesses(f)             self._get_const_accesses(f)             self._get_attr_accessors(f)             self._get_attr_access_modifiers(f)             self._get_constant_literals(f)             self._get_constant_values(f)          finally:             f.close()      def complete(self):         self.propagate()      def _get_imports(self, f):         f.readline() # "imports:"         line = f.readline().strip()         self.required = line != "{}" and set(line.split(", ")) or set()         line = f.readline().strip()         self.imports = line != "{}" and set(line.split(", ")) or set()         f.readline()          for name in self.required:             self.queue_module(name, True)         for name in self.imports:             self.queue_module(name)      def _get_members(self, f):         f.readline() # "members:"         line = f.readline().rstrip()         while line:             name, ref = line.split(" ", 1)             self.set_object(name, ref)             line = f.readline().rstrip()      def _get_class_relationships(self, f):         f.readline() # "class relationships:"         line = f.readline().rstrip()         while line:             name, value = self._get_fields(line)             values = value and value.split(", ") or []             self.importer.classes[name] = self.classes[name] = map(decode_reference, values)             self.importer.subclasses[name] = set()             line = f.readline().rstrip()      def _get_instance_attrs(self, f):         f.readline() # "instance attributes:"         line = f.readline().rstrip()         while line:             name, value = self._get_fields(line)             self.importer.all_instance_attrs[name] = self.instance_attrs[name] = set(value and value.split(", ") or [])             line = f.readline().rstrip()      def _get_instance_attr_constants(self, f):         f.readline() # "instance attribute constants:"         line = f.readline().rstrip()         while line:             name, attrname, ref = self._get_fields(line, 3)             init_item(self.instance_attr_constants, name, dict)             self.instance_attr_constants[name][attrname] = decode_reference(ref)             line = f.readline().rstrip()      def _get_name_references(self, f):         f.readline() # "name references:"         line = f.readline().rstrip()         while line:             name, ref = self._get_fields(line)             self.importer.all_name_references[name] = self.name_references[name] = decode_reference(ref)             line = f.readline().rstrip()      def _get_initialised_names(self, f):         f.readline() # "initialised names:"         line = f.readline().rstrip()         while line:             name, version, value = self._get_fields(line, 3)             init_item(self.initialised_names, name, dict)             self.initialised_names[name][int(version)] = decode_reference(value)             line = f.readline().rstrip()      def _get_aliased_names(self, f):         f.readline() # "aliased names:"         line = f.readline().rstrip()         while line:             name, version, original_name, attrnames, number = self._get_fields(line, 5)             init_item(self.aliased_names, name, dict)             if number == "{}": number = None             else: number = int(number)             self.aliased_names[name][int(version)] = (original_name, attrnames != "{}" and attrnames or None, number)             line = f.readline().rstrip()      def _get_function_parameters(self, f):         f.readline() # "function parameters:"         line = f.readline().rstrip()         while line:             function, names = self._get_fields(line)             self.importer.function_parameters[function] = \                 self.function_parameters[function] = names != "{}" and names.split(", ") or []             line = f.readline().rstrip()      def _get_function_defaults(self, f):         f.readline() # "function default parameters:"         line = f.readline().rstrip()         while line:             function, defaults = self._get_fields(line)             self.importer.function_defaults[function] = \                 self.function_defaults[function] = l = []             if defaults != "{}":                 for value in defaults.split(", "):                     name, default = value.split("=")                     default = decode_reference(default)                     l.append((name, default))             line = f.readline().rstrip()      def _get_function_locals(self, f):         f.readline() # "function locals:"         line = f.readline().rstrip()         while line:             function, name, value = self._get_fields(line, 3)             init_item(self.function_locals, function, dict)             if name != "{}":                 self.function_locals[function][name] = decode_reference(value)             line = f.readline().rstrip()      def _get_function_targets(self, f):         f.readline() # "function targets:"         line = f.readline().rstrip()         while line:             function, n = self._get_fields(line)             self.importer.function_targets[function] = \                 self.function_targets[function] = int(n)             line = f.readline().rstrip()      def _get_function_arguments(self, f):         f.readline() # "function arguments:"         line = f.readline().rstrip()         while line:             function, n = self._get_fields(line)             self.importer.function_arguments[function] = \                 self.function_arguments[function] = int(n)             line = f.readline().rstrip()      def _get_attribute_usage(self, f):         f.readline() # "attribute usage:"         line = f.readline().rstrip()         while line:             unit, value = self._get_fields(line)             init_item(self.attr_usage, unit, dict)             self.usage_from_cache(value, self.attr_usage[unit])             line = f.readline().rstrip()      def _get_attr_accesses(self, f):         f.readline() # "attribute accesses:"         line = f.readline().rstrip()         while line:             name, value = self._get_fields(line)             self.attr_accesses[name] = set(value.split(", "))             line = f.readline().rstrip()      def _get_const_accesses(self, f):         f.readline() # "constant accesses:"         line = f.readline().rstrip()         while line:             name, original_name, attrnames, objpath, ref, remaining = self._get_fields(line, 6)             if attrnames == "{}": attrnames = None             init_item(self.const_accesses, name, dict)             self.const_accesses[name][(original_name, attrnames)] = (objpath, decode_reference(ref), remaining != "{}" and remaining or "")             line = f.readline().rstrip()      def _get_attr_accessors(self, f):         f.readline() # "attribute access usage:"         line = f.readline().rstrip()         while line:             objpath, name, attrname, value = self._get_fields(line, 4)             if attrname == "{}": attrname = None             access = name, attrname             init_item(self.attr_accessors, objpath, dict)             init_item(self.attr_accessors[objpath], access, list)             positions = map(int, value.split(", "))             self.attr_accessors[objpath][access].append(positions)             line = f.readline().rstrip()      def _get_attr_access_modifiers(self, f):         f.readline() # "attribute access modifiers:"         line = f.readline().rstrip()         while line:             objpath, name, attrnames, value = self._get_fields(line, 4)             if name == "{}": name = None             if attrnames == "{}": attrnames = None             access = name, attrnames             init_item(self.attr_access_modifiers, objpath, dict)             init_item(self.attr_access_modifiers[objpath], access, list)             modifiers = [decode_modifier_term(s) for s in value]             self.attr_access_modifiers[objpath][access] = modifiers             line = f.readline().rstrip()      def _get_constant_literals(self, f):         f.readline() # "constant literals:"         line = f.readline().rstrip()         last_path = None         n = None         while line:             path, constant = self._get_fields(line)             if path != last_path:                 n = 0                 last_path = path             else:                 n += 1             init_item(self.constants, path, dict)             self.constants[path][eval(constant)] = n             line = f.readline().rstrip()      def _get_constant_values(self, f):         f.readline() # "constant values:"         line = f.readline().rstrip()         while line:             name, value_type, value = self._get_fields(line, 3)             self.constant_values[name] = eval(value), value_type             line = f.readline().rstrip()      # Generic parsing methods.      def from_lines(self, f, d):          "Read lines from 'f', populating 'd'."          f.readline() # section heading         line = f.readline().rstrip()         while line:             name, value = self._get_fields(line)             d[name] = set(value and value.split(", ") or [])             line = f.readline().rstrip()      def usage_from_cache(self, value, mapping):          """         Interpret the given 'value' containing name and usage information,         storing the information in the given 'mapping'.         """          local, usage = self._get_fields(value)         init_item(mapping, local, list)         self._usage_from_cache(mapping[local], usage)      def _usage_from_cache(self, d, usage):          # Interpret descriptions of each version of the name.          all_usages = set()         for attrnames in usage.split("; "):             if attrnames == "{}":                 all_attrnames = ()             else:                 all_attrnames = decode_usage(attrnames)             all_usages.add(all_attrnames)          d.append(all_usages)      def _get_fields(self, s, n=2):         result = s.split(" ", n-1)         if len(result) == n:             return result         else:             return tuple(result) + tuple([""] * (n - len(result)))  class CacheWritingModule:      """     A mix-in providing cache-writing support, to be combined with BasicModule.     """      def to_cache(self, filename):          """         Write a cached representation of the inspected module with the following         format to the file having the given 'filename':          filename         (empty line)         "imports:"         required module names         possibly required module names         "members:"         zero or more: qualified name " " reference         (empty line)         "class relationships:"         zero or more: qualified class name " " base class references         (empty line)         "instance attributes:"         zero or more: qualified class name " " instance attribute names         (empty line)         "instance attribute constants:"         zero or more: qualified class name " " attribute name " " reference         (empty line)         "names used:"         zero or more: qualified class/function/module name " " names         (empty line)         "names missing:"         zero or more: qualified class/function/module name " " names         (empty line)         "name references:"         zero or more: qualified name " " reference         (empty line)         "initialised names:"         zero or more: qualified name " " definition version " " reference         (empty line)         "aliased names:"         zero or more: qualified name " " definition version " " original name " " attribute names " " access number         (empty line)         "function parameters:"         zero or more: qualified function name " " parameter names         (empty line)         "function default parameters:"         zero or more: qualified function name " " parameter names with defaults         (empty line)         "function locals:"         zero or more: qualified function name " " local variable name " " reference         (empty line)         "scope globals:"         zero or more: qualified function name " " global variable names         (empty line)         "function targets:"         zero or more: qualified function name " " maximum number of targets allocated         (empty line)         "function arguments:"         zero or more: qualified function name " " maximum number of arguments allocated         (empty line)         "attribute usage:"         zero or more: qualified scope name " " local/global/qualified variable name " " usages         (empty line)         "attribute accesses:"         zero or more: qualified scope name " " attribute-chains         (empty line)         "constant accesses:"         zero or more: qualified function name " " attribute-chain " " reference " " remaining attribute-chain         (empty line)         "attribute access usage:"         zero or more: qualified function name " " local/global variable name " " attribute name " " definition versions         (empty line)         "attribute access modifiers:"         zero or more: qualified function name " " local/global variable name " " attribute name " " access modifiers         "constant literals:"         zero or more: qualified scope name " " constant literal         "constant values:"         zero or more: qualified name " " value type " " constant literal          All collections of names are separated by ", " characters.          References can be "<var>", a module name, or one of "<class>" or         "<function>" followed optionally by a ":" character and a qualified         name.          Parameter names with defaults are separated by ", " characters, with         each name followed by "=" and then followed by a reference. If "{}" is         indicated, no defaults are defined for the function. Similarly, function         locals may be indicated as "{}" meaning that there are no locals.          All usages (attribute usage sets) are separated by "; " characters, with         the special string "{}" representing an empty set.          Each usage is a collection of names separated by ", " characters, with         assigned attribute names suffixed with a "*" character.          Each attribute-chain expression is a dot-separated chain of attribute         names, with assignments suffixed with a "*" character.          Definition versions are separated by ", " characters and indicate the         name definition version associated with the access.          Access modifiers are separated by ", " characters and indicate features         of each access, with multiple accesses described on a single line.         """          f = open(filename, "w")         try:             print >>f, self.filename              print >>f             print >>f, "imports:"             required = list(self.required)             required.sort()             print >>f, required and ", ".join(required) or "{}"             imports = list(self.imports)             imports.sort()             print >>f, imports and ", ".join(imports) or "{}"              print >>f             print >>f, "members:"             objects = self.objects.keys()             objects.sort()             for name in objects:                 print >>f, name, self.objects[name]              print >>f             print >>f, "class relationships:"             classes = self.classes.keys()             classes.sort()             for class_ in classes:                 bases = self.classes[class_]                 if bases:                     print >>f, class_, ", ".join(map(str, bases))                 else:                     print >>f, class_              self.to_lines(f, "instance attributes:", self.instance_attrs)              print >>f             print >>f, "instance attribute constants:"             classes = self.instance_attr_constants.items()             classes.sort()             for name, attrs in classes:                 attrs = attrs.items()                 attrs.sort()                 for attrname, ref in attrs:                     print >>f, name, attrname, ref              self.to_lines(f, "names used:", self.names_used)              print >>f             print >>f, "name references:"             refs = self.name_references.items()             refs.sort()             for name, ref in refs:                 print >>f, name, ref              print >>f             print >>f, "initialised names:"             assignments = self.initialised_names.items()             assignments.sort()             for name, refs in assignments:                 versions = refs.items()                 versions.sort()                 for version, ref in versions:                     print >>f, name, version, ref              print >>f             print >>f, "aliased names:"             assignments = self.aliased_names.items()             assignments.sort()             for name, aliases in assignments:                 versions = aliases.items()                 versions.sort()                 for version, alias in versions:                     original_name, attrnames, number = alias                     print >>f, name, version, original_name, attrnames or "{}", number is None and "{}" or number              print >>f             print >>f, "function parameters:"             functions = self.function_parameters.keys()             functions.sort()             for function in functions:                 parameters = self.function_parameters[function]                 if parameters:                     print >>f, function, ", ".join(parameters)                 else:                     print >>f, function, "{}"              print >>f             print >>f, "function default parameters:"             functions = self.function_defaults.keys()             functions.sort()             for function in functions:                 parameters = self.function_defaults[function]                 if parameters:                     print >>f, function, ", ".join([("%s=%s" % (name, default)) for (name, default) in parameters])                 else:                     print >>f, function, "{}"              print >>f             print >>f, "function locals:"             functions = self.function_locals.keys()             functions.sort()             for function in functions:                 names = self.function_locals[function].items()                 if names:                     names.sort()                     for name, value in names:                         print >>f, function, name, value                 else:                     print >>f, function, "{}"              self.to_lines(f, "scope globals:", self.scope_globals)              print >>f             print >>f, "function targets:"             functions = self.function_targets.keys()             functions.sort()             for function in functions:                 print >>f, function, self.function_targets[function]              print >>f             print >>f, "function arguments:"             functions = self.function_arguments.keys()             functions.sort()             for function in functions:                 print >>f, function, self.function_arguments[function]              print >>f             print >>f, "attribute usage:"             units = self.attr_usage.keys()             units.sort()             for unit in units:                 d = self.attr_usage[unit]                 self.usage_to_cache(d, f, unit)              print >>f             print >>f, "attribute accesses:"             paths = self.attr_accesses.keys()             paths.sort()             for path in paths:                 accesses = list(self.attr_accesses[path])                 accesses.sort()                 print >>f, path, ", ".join(accesses)              print >>f             print >>f, "constant accesses:"             paths = self.const_accesses.keys()             paths.sort()             for path in paths:                 accesses = self.const_accesses[path].items()                 accesses.sort()                 for (original_name, attrnames), (objpath, ref, remaining_attrnames) in accesses:                     print >>f, path, original_name, attrnames, objpath, ref, remaining_attrnames or "{}"              print >>f             print >>f, "attribute access usage:"             paths = self.attr_accessors.keys()             paths.sort()             for path in paths:                 all_accesses = self.attr_accessors[path].items()                 all_accesses.sort()                 for (name, attrname), accesses in all_accesses:                     for positions in accesses:                         positions = map(str, positions)                         print >>f, path, name, attrname or "{}", ", ".join(positions)              print >>f             print >>f, "attribute access modifiers:"             paths = self.attr_access_modifiers.keys()             paths.sort()             for path in paths:                 all_accesses = self.attr_access_modifiers[path].items()                 all_accesses.sort()                 for (name, attrnames), modifiers in all_accesses:                     print >>f, path, name or "{}", attrnames or "{}", encode_modifiers(modifiers)              print >>f             print >>f, "constant literals:"             paths = self.constants.keys()             paths.sort()             for path in paths:                 constants = [(v, k) for (k, v) in self.constants[path].items()]                 constants.sort()                 for n, constant in constants:                     print >>f, path, repr(constant)              print >>f             print >>f, "constant values:"             names = self.constant_values.keys()             names.sort()             for name in names:                 value, value_type = self.constant_values[name]                 print >>f, name, value_type, repr(value)          finally:             f.close()      def to_lines(self, f, heading, d):          "Write lines to 'f' with the given 'heading', using 'd'."          print >>f         print >>f, heading         keys = d.keys()         keys.sort()         for key in keys:             attrs = list(d[key])             if attrs:                 attrs.sort()                 print >>f, key, ", ".join(attrs)      def usage_to_cache(self, details, f, prefix):          "Write the given namespace usage details to the cache."          names = list(details.keys())         if names:             names.sort()             for name in names:                 if details[name]:                      # Produce descriptions for each version of the name.                      for version in details[name]:                         all_usages = []                         for usage in version:                             all_usages.append(encode_usage(usage))                          print >>f, "%s %s %s" % (prefix, name, "; ".join(all_usages))  # vim: tabstop=4 expandtab shiftwidth=4