1 #!/usr/bin/env python 2 3 """ 4 Common functions. 5 6 Copyright (C) 2007, 2008, 2009, 2010, 2011, 2012, 2013, 7 2014, 2015, 2016, 2017 Paul Boddie <paul@boddie.org.uk> 8 9 This program is free software; you can redistribute it and/or modify it under 10 the terms of the GNU General Public License as published by the Free Software 11 Foundation; either version 3 of the License, or (at your option) any later 12 version. 13 14 This program is distributed in the hope that it will be useful, but WITHOUT 15 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS 16 FOR A PARTICULAR PURPOSE. See the GNU General Public License for more 17 details. 18 19 You should have received a copy of the GNU General Public License along with 20 this program. If not, see <http://www.gnu.org/licenses/>. 21 """ 22 23 from compiler.transformer import Transformer 24 from errors import InspectError 25 from os import listdir, makedirs, remove 26 from os.path import exists, getmtime, isdir, join, split 27 from results import ConstantValueRef, LiteralSequenceRef, NameRef 28 import compiler.ast 29 30 class CommonOutput: 31 32 "Common output functionality." 33 34 def check_output(self, options=None): 35 36 "Check the existing output and remove it if irrelevant." 37 38 if not exists(self.output): 39 makedirs(self.output) 40 41 details = self.importer.get_cache_details() 42 recorded_details = self.get_output_details() 43 44 # Combine cache details with any options. 45 46 full_details = options and (details + " " + options) or details 47 48 if recorded_details != full_details: 49 self.remove_output() 50 51 writefile(self.get_output_details_filename(), full_details) 52 53 def get_output_details_filename(self): 54 55 "Return the output details filename." 56 57 return join(self.output, "$details") 58 59 def get_output_details(self): 60 61 "Return details of the existing output." 62 63 details_filename = self.get_output_details_filename() 64 65 if not exists(details_filename): 66 return None 67 else: 68 return readfile(details_filename) 69 70 def remove_output(self, dirname=None): 71 72 "Remove the output." 73 74 dirname = dirname or self.output 75 76 for filename in listdir(dirname): 77 path = join(dirname, filename) 78 if isdir(path): 79 self.remove_output(path) 80 else: 81 remove(path) 82 83 def copy(source, target, only_if_newer=True): 84 85 "Copy a text file from 'source' to 'target'." 86 87 if isdir(target): 88 target = join(target, split(source)[-1]) 89 90 if only_if_newer and not is_newer(source, target): 91 return 92 93 infile = open(source) 94 outfile = open(target, "w") 95 96 try: 97 outfile.write(infile.read()) 98 finally: 99 outfile.close() 100 infile.close() 101 102 def is_newer(source, target): 103 104 "Return whether 'source' is newer than 'target'." 105 106 if exists(target): 107 target_mtime = getmtime(target) 108 source_mtime = getmtime(source) 109 return source_mtime > target_mtime 110 111 return True 112 113 class CommonModule: 114 115 "A common module representation." 116 117 def __init__(self, name, importer): 118 119 """ 120 Initialise this module with the given 'name' and an 'importer' which is 121 used to provide access to other modules when required. 122 """ 123 124 self.name = name 125 self.importer = importer 126 self.filename = None 127 128 # Inspection-related attributes. 129 130 self.astnode = None 131 self.encoding = None 132 self.temp = {} 133 self.lambdas = {} 134 135 # Constants, literals and values. 136 137 self.constants = {} 138 self.constant_values = {} 139 self.literals = {} 140 self.literal_types = {} 141 142 # Nested namespaces. 143 144 self.namespace_path = [] 145 self.in_function = False 146 147 # Retain the assignment value expression and track invocations. 148 149 self.in_assignment = None 150 self.in_invocation = None 151 152 # Attribute chain state management. 153 154 self.attrs = [] 155 self.chain_assignment = [] 156 self.chain_invocation = [] 157 158 def __repr__(self): 159 return "CommonModule(%r, %r)" % (self.name, self.importer) 160 161 def parse_file(self, filename): 162 163 "Parse the file with the given 'filename', initialising attributes." 164 165 self.filename = filename 166 167 # Use the Transformer directly to obtain encoding information. 168 169 t = Transformer() 170 f = open(filename) 171 172 try: 173 self.astnode = t.parsesuite(f.read() + "\n") 174 self.encoding = t.encoding 175 finally: 176 f.close() 177 178 # Module-relative naming. 179 180 def get_global_path(self, name): 181 return "%s.%s" % (self.name, name) 182 183 def get_namespace_path(self): 184 return ".".join([self.name] + self.namespace_path) 185 186 def get_object_path(self, name): 187 return ".".join([self.name] + self.namespace_path + [name]) 188 189 def get_parent_path(self): 190 return ".".join([self.name] + self.namespace_path[:-1]) 191 192 # Namespace management. 193 194 def enter_namespace(self, name): 195 196 "Enter the namespace having the given 'name'." 197 198 self.namespace_path.append(name) 199 200 def exit_namespace(self): 201 202 "Exit the current namespace." 203 204 self.namespace_path.pop() 205 206 # Constant reference naming. 207 208 def get_constant_name(self, value, value_type, encoding=None): 209 210 """ 211 Add a new constant to the current namespace for 'value' with 212 'value_type'. 213 """ 214 215 path = self.get_namespace_path() 216 init_item(self.constants, path, dict) 217 return "$c%d" % add_counter_item(self.constants[path], (value, value_type, encoding)) 218 219 # Literal reference naming. 220 221 def get_literal_name(self): 222 223 "Add a new literal to the current namespace." 224 225 path = self.get_namespace_path() 226 init_item(self.literals, path, lambda: 0) 227 return "$C%d" % self.literals[path] 228 229 def next_literal(self): 230 self.literals[self.get_namespace_path()] += 1 231 232 # Temporary variable naming. 233 234 def get_temporary_name(self): 235 path = self.get_namespace_path() 236 init_item(self.temp, path, lambda: 0) 237 return "$t%d" % self.temp[path] 238 239 def next_temporary(self): 240 self.temp[self.get_namespace_path()] += 1 241 242 # Arbitrary function naming. 243 244 def get_lambda_name(self): 245 path = self.get_namespace_path() 246 init_item(self.lambdas, path, lambda: 0) 247 name = "$l%d" % self.lambdas[path] 248 self.lambdas[path] += 1 249 return name 250 251 def reset_lambdas(self): 252 self.lambdas = {} 253 254 # Constant and literal recording. 255 256 def get_constant_value(self, value, literals=None): 257 258 """ 259 Encode the 'value' if appropriate, returning a value, a typename and any 260 encoding. 261 """ 262 263 if isinstance(value, unicode): 264 return value.encode("utf-8"), "unicode", self.encoding 265 266 # Attempt to convert plain strings to text. 267 268 elif isinstance(value, str) and self.encoding: 269 try: 270 return get_string_details(literals, self.encoding) 271 except UnicodeDecodeError: 272 pass 273 274 return value, value.__class__.__name__, None 275 276 def get_constant_reference(self, ref, value, encoding=None): 277 278 """ 279 Return a constant reference for the given 'ref' type and 'value', with 280 the optional 'encoding' applying to text values. 281 """ 282 283 constant_name = self.get_constant_name(value, ref.get_origin(), encoding) 284 285 # Return a reference for the constant. 286 287 objpath = self.get_object_path(constant_name) 288 name_ref = ConstantValueRef(constant_name, ref.instance_of(objpath), value) 289 290 # Record the value and type for the constant. 291 292 self._reserve_constant(objpath, name_ref.value, name_ref.get_origin(), encoding) 293 return name_ref 294 295 def reserve_constant(self, objpath, value, origin, encoding=None): 296 297 """ 298 Reserve a constant within 'objpath' with the given 'value' and having a 299 type with the given 'origin', with the optional 'encoding' applying to 300 text values. 301 """ 302 303 constant_name = self.get_constant_name(value, origin) 304 objpath = self.get_object_path(constant_name) 305 self._reserve_constant(objpath, value, origin, encoding) 306 307 def _reserve_constant(self, objpath, value, origin, encoding): 308 309 """ 310 Store a constant for 'objpath' with the given 'value' and 'origin', with 311 the optional 'encoding' applying to text values. 312 """ 313 314 self.constant_values[objpath] = value, origin, encoding 315 316 def get_literal_reference(self, name, ref, items, cls): 317 318 """ 319 Return a literal reference for the given type 'name', literal 'ref', 320 node 'items' and employing the given 'cls' as the class of the returned 321 reference object. 322 """ 323 324 # Construct an invocation using the items as arguments. 325 326 typename = "$L%s" % name 327 328 invocation = compiler.ast.CallFunc( 329 compiler.ast.Name(typename), 330 items 331 ) 332 333 # Get a name for the actual literal. 334 335 instname = self.get_literal_name() 336 self.next_literal() 337 338 # Record the type for the literal. 339 340 objpath = self.get_object_path(instname) 341 self.literal_types[objpath] = ref.get_origin() 342 343 # Return a wrapper for the invocation exposing the items. 344 345 return cls( 346 instname, 347 ref.instance_of(), 348 self.process_structure_node(invocation), 349 invocation.args 350 ) 351 352 # Node handling. 353 354 def process_structure(self, node): 355 356 """ 357 Within the given 'node', process the program structure. 358 359 During inspection, this will process global declarations, adjusting the 360 module namespace, and import statements, building a module dependency 361 hierarchy. 362 363 During translation, this will consult deduced program information and 364 output translated code. 365 """ 366 367 l = [] 368 for n in node.getChildNodes(): 369 l.append(self.process_structure_node(n)) 370 return l 371 372 def process_augassign_node(self, n): 373 374 "Process the given augmented assignment node 'n'." 375 376 op = operator_functions[n.op] 377 378 if isinstance(n.node, compiler.ast.Getattr): 379 target = compiler.ast.AssAttr(n.node.expr, n.node.attrname, "OP_ASSIGN") 380 elif isinstance(n.node, compiler.ast.Name): 381 target = compiler.ast.AssName(n.node.name, "OP_ASSIGN") 382 else: 383 target = n.node 384 385 assignment = compiler.ast.Assign( 386 [target], 387 compiler.ast.CallFunc( 388 compiler.ast.Name("$op%s" % op), 389 [n.node, n.expr])) 390 391 return self.process_structure_node(assignment) 392 393 def process_assignment_for_object(self, original_name, source): 394 395 """ 396 Return an assignment operation making 'original_name' refer to the given 397 'source'. 398 """ 399 400 assignment = compiler.ast.Assign( 401 [compiler.ast.AssName(original_name, "OP_ASSIGN")], 402 source 403 ) 404 405 return self.process_structure_node(assignment) 406 407 def process_assignment_node_items(self, n, expr): 408 409 """ 410 Process the given assignment node 'n' whose children are to be assigned 411 items of 'expr'. 412 """ 413 414 name_ref = self.process_structure_node(expr) 415 416 # Either unpack the items and present them directly to each assignment 417 # node. 418 419 if isinstance(name_ref, LiteralSequenceRef) and \ 420 self.process_literal_sequence_items(n, name_ref): 421 422 pass 423 424 # Or have the assignment nodes access each item via the sequence API. 425 426 else: 427 self.process_assignment_node_items_by_position(n, expr, name_ref) 428 429 def process_assignment_node_items_by_position(self, n, expr, name_ref): 430 431 """ 432 Process the given sequence assignment node 'n', converting the node to 433 the separate assignment of each target using positional access on a 434 temporary variable representing the sequence. Use 'expr' as the assigned 435 value and 'name_ref' as the reference providing any existing temporary 436 variable. 437 """ 438 439 assignments = [] 440 441 # Employ existing names to access the sequence. 442 # Literal sequences do not provide names of accessible objects. 443 444 if isinstance(name_ref, NameRef) and not isinstance(name_ref, LiteralSequenceRef): 445 temp = name_ref.name 446 447 # For other expressions, create a temporary name to reference the items. 448 449 else: 450 temp = self.get_temporary_name() 451 self.next_temporary() 452 453 assignments.append( 454 compiler.ast.Assign([compiler.ast.AssName(temp, "OP_ASSIGN")], expr) 455 ) 456 457 # Assign the items to the target nodes. 458 459 for i, node in enumerate(n.nodes): 460 assignments.append( 461 compiler.ast.Assign([node], compiler.ast.Subscript( 462 compiler.ast.Name(temp), "OP_APPLY", [compiler.ast.Const(i, str(i))])) 463 ) 464 465 return self.process_structure_node(compiler.ast.Stmt(assignments)) 466 467 def process_literal_sequence_items(self, n, name_ref): 468 469 """ 470 Process the given assignment node 'n', obtaining from the given 471 'name_ref' the items to be assigned to the assignment targets. 472 473 Return whether this method was able to process the assignment node as 474 a sequence of direct assignments. 475 """ 476 477 if len(n.nodes) == len(name_ref.items): 478 assigned_names, count = get_names_from_nodes(n.nodes) 479 accessed_names, _count = get_names_from_nodes(name_ref.items) 480 481 # Only assign directly between items if all assigned names are 482 # plain names (not attribute assignments), and if the assigned names 483 # do not appear in the accessed names. 484 485 if len(assigned_names) == count and \ 486 not assigned_names.intersection(accessed_names): 487 488 for node, item in zip(n.nodes, name_ref.items): 489 self.process_assignment_node(node, item) 490 491 return True 492 493 # Otherwise, use the position-based mechanism to obtain values. 494 495 else: 496 return False 497 else: 498 raise InspectError("In %s, item assignment needing %d items is given %d items." % ( 499 self.get_namespace_path(), len(n.nodes), len(name_ref.items))) 500 501 def process_compare_node(self, n): 502 503 """ 504 Process the given comparison node 'n', converting an operator sequence 505 from... 506 507 <expr1> <op1> <expr2> <op2> <expr3> 508 509 ...to... 510 511 <op1>(<expr1>, <expr2>) and <op2>(<expr2>, <expr3>) 512 """ 513 514 invocations = [] 515 last = n.expr 516 517 for op, op_node in n.ops: 518 op = operator_functions.get(op) 519 520 invocations.append(compiler.ast.CallFunc( 521 compiler.ast.Name("$op%s" % op), 522 [last, op_node])) 523 524 last = op_node 525 526 if len(invocations) > 1: 527 result = compiler.ast.And(invocations) 528 else: 529 result = invocations[0] 530 531 return self.process_structure_node(result) 532 533 def process_dict_node(self, node): 534 535 """ 536 Process the given dictionary 'node', returning a list of (key, value) 537 tuples. 538 """ 539 540 l = [] 541 for key, value in node.items: 542 l.append(( 543 self.process_structure_node(key), 544 self.process_structure_node(value))) 545 return l 546 547 def process_for_node(self, n): 548 549 """ 550 Generate attribute accesses for {n.list}.__iter__ and the next method on 551 the iterator, producing a replacement node for the original. 552 """ 553 554 t0 = self.get_temporary_name() 555 self.next_temporary() 556 t1 = self.get_temporary_name() 557 self.next_temporary() 558 559 node = compiler.ast.Stmt([ 560 561 # <t0> = {n.list} 562 # <t1> = <t0>.__iter__() 563 564 compiler.ast.Assign( 565 [compiler.ast.AssName(t0, "OP_ASSIGN")], 566 n.list), 567 568 compiler.ast.Assign( 569 [compiler.ast.AssName(t1, "OP_ASSIGN")], 570 compiler.ast.CallFunc( 571 compiler.ast.Getattr(compiler.ast.Name(t0), "__iter__"), 572 [])), 573 574 # try: 575 # while True: 576 # <var>... = <t1>.next() 577 # ... 578 # except StopIteration: 579 # pass 580 581 compiler.ast.TryExcept( 582 compiler.ast.While( 583 compiler.ast.Name("True"), 584 compiler.ast.Stmt([ 585 compiler.ast.Assign( 586 [n.assign], 587 compiler.ast.CallFunc( 588 compiler.ast.Getattr(compiler.ast.Name(t1), "next"), 589 [] 590 )), 591 n.body]), 592 None), 593 [(compiler.ast.Name("StopIteration"), None, compiler.ast.Stmt([compiler.ast.Pass()]))], 594 None) 595 ]) 596 597 self.process_structure_node(node) 598 599 def process_literal_sequence_node(self, n, name, ref, cls): 600 601 """ 602 Process the given literal sequence node 'n' as a function invocation, 603 with 'name' indicating the type of the sequence, and 'ref' being a 604 reference to the type. The 'cls' is used to instantiate a suitable name 605 reference. 606 """ 607 608 if name == "dict": 609 items = [] 610 for key, value in n.items: 611 items.append(compiler.ast.Tuple([key, value])) 612 else: # name in ("list", "tuple"): 613 items = n.nodes 614 615 return self.get_literal_reference(name, ref, items, cls) 616 617 def process_operator_node(self, n): 618 619 """ 620 Process the given operator node 'n' as an operator function invocation. 621 """ 622 623 op = operator_functions[n.__class__.__name__] 624 invocation = compiler.ast.CallFunc( 625 compiler.ast.Name("$op%s" % op), 626 list(n.getChildNodes()) 627 ) 628 return self.process_structure_node(invocation) 629 630 def process_print_node(self, n): 631 632 """ 633 Process the given print node 'n' as an invocation on a stream of the 634 form... 635 636 $print(dest, args, nl) 637 638 The special function name will be translated elsewhere. 639 """ 640 641 nl = isinstance(n, compiler.ast.Printnl) 642 invocation = compiler.ast.CallFunc( 643 compiler.ast.Name("$print"), 644 [n.dest or compiler.ast.Name("None"), 645 compiler.ast.List(list(n.nodes)), 646 nl and compiler.ast.Name("True") or compiler.ast.Name("False")] 647 ) 648 return self.process_structure_node(invocation) 649 650 def process_slice_node(self, n, expr=None): 651 652 """ 653 Process the given slice node 'n' as a method invocation. 654 """ 655 656 if n.flags == "OP_ASSIGN": op = "__setslice__" 657 elif n.flags == "OP_DELETE": op = "__delslice__" 658 else: op = "__getslice__" 659 660 invocation = compiler.ast.CallFunc( 661 compiler.ast.Getattr(n.expr, op), 662 [n.lower or compiler.ast.Name("None"), n.upper or compiler.ast.Name("None")] + 663 (expr and [expr] or []) 664 ) 665 666 # Fix parse tree structure. 667 668 if op == "__delslice__": 669 invocation = compiler.ast.Discard(invocation) 670 671 return self.process_structure_node(invocation) 672 673 def process_sliceobj_node(self, n): 674 675 """ 676 Process the given slice object node 'n' as a slice constructor. 677 """ 678 679 op = "slice" 680 invocation = compiler.ast.CallFunc( 681 compiler.ast.Name("$op%s" % op), 682 n.nodes 683 ) 684 return self.process_structure_node(invocation) 685 686 def process_subscript_node(self, n, expr=None): 687 688 """ 689 Process the given subscript node 'n' as a method invocation. 690 """ 691 692 if n.flags == "OP_ASSIGN": op = "__setitem__" 693 elif n.flags == "OP_DELETE": op = "__delitem__" 694 else: op = "__getitem__" 695 696 invocation = compiler.ast.CallFunc( 697 compiler.ast.Getattr(n.expr, op), 698 list(n.subs) + (expr and [expr] or []) 699 ) 700 701 # Fix parse tree structure. 702 703 if op == "__delitem__": 704 invocation = compiler.ast.Discard(invocation) 705 706 return self.process_structure_node(invocation) 707 708 def process_attribute_chain(self, n): 709 710 """ 711 Process the given attribute access node 'n'. Return a reference 712 describing the expression. 713 """ 714 715 # AssAttr/Getattr are nested with the outermost access being the last 716 # access in any chain. 717 718 self.attrs.insert(0, n.attrname) 719 attrs = self.attrs 720 721 # Break attribute chains where non-access nodes are found. 722 723 if not self.have_access_expression(n): 724 self.reset_attribute_chain() 725 726 # Descend into the expression, extending backwards any existing chain, 727 # or building another for the expression. 728 729 name_ref = self.process_structure_node(n.expr) 730 731 # Restore chain information applying to this node. 732 733 if not self.have_access_expression(n): 734 self.restore_attribute_chain(attrs) 735 736 # Return immediately if the expression was another access and thus a 737 # continuation backwards along the chain. The above processing will 738 # have followed the chain all the way to its conclusion. 739 740 if self.have_access_expression(n): 741 del self.attrs[0] 742 743 return name_ref 744 745 # Attribute chain handling. 746 747 def reset_attribute_chain(self): 748 749 "Reset the attribute chain for a subexpression of an attribute access." 750 751 self.attrs = [] 752 self.chain_assignment.append(self.in_assignment) 753 self.chain_invocation.append(self.in_invocation) 754 self.in_assignment = None 755 self.in_invocation = None 756 757 def restore_attribute_chain(self, attrs): 758 759 "Restore the attribute chain for an attribute access." 760 761 self.attrs = attrs 762 self.in_assignment = self.chain_assignment.pop() 763 self.in_invocation = self.chain_invocation.pop() 764 765 def have_access_expression(self, node): 766 767 "Return whether the expression associated with 'node' is Getattr." 768 769 return isinstance(node.expr, compiler.ast.Getattr) 770 771 def get_name_for_tracking(self, name, name_ref=None, is_global=False): 772 773 """ 774 Return the name to be used for attribute usage observations involving 775 the given 'name' in the current namespace. 776 777 If the name is being used outside a function, and if 'name_ref' is 778 given and indicates a global or if 'is_global' is specified as a true 779 value, a path featuring the name in the global namespace is returned. 780 Otherwise, a path computed using the current namespace and the given 781 name is returned. 782 783 The intention of this method is to provide a suitably-qualified name 784 that can be tracked across namespaces. Where globals are being 785 referenced in class namespaces, they should be referenced using their 786 path within the module, not using a path within each class. 787 788 It may not be possible to identify a global within a function at the 789 time of inspection (since a global may appear later in a file). 790 Consequently, globals are identified by their local name rather than 791 their module-qualified path. 792 """ 793 794 # For functions, use the appropriate local names. 795 796 if self.in_function: 797 return name 798 799 # For global names outside functions, use a global name. 800 801 elif is_global or name_ref and name_ref.is_global_name(): 802 return self.get_global_path(name) 803 804 # Otherwise, establish a name in the current namespace. 805 806 else: 807 return self.get_object_path(name) 808 809 def get_path_for_access(self): 810 811 "Outside functions, register accesses at the module level." 812 813 if not self.in_function: 814 return self.name 815 else: 816 return self.get_namespace_path() 817 818 def get_module_name(self, node): 819 820 """ 821 Using the given From 'node' in this module, calculate any relative import 822 information, returning a tuple containing a module to import along with any 823 names to import based on the node's name information. 824 825 Where the returned module is given as None, whole module imports should 826 be performed for the returned modules using the returned names. 827 """ 828 829 # Absolute import. 830 831 if node.level == 0: 832 return node.modname, node.names 833 834 # Relative to an ancestor of this module. 835 836 else: 837 path = self.name.split(".") 838 level = node.level 839 840 # Relative imports treat package roots as submodules. 841 842 if split(self.filename)[-1] == "__init__.py": 843 level -= 1 844 845 if level > len(path): 846 raise InspectError("Relative import %r involves too many levels up from module %r" % ( 847 ("%s%s" % ("." * node.level, node.modname or "")), self.name)) 848 849 basename = ".".join(path[:len(path)-level]) 850 851 # Name imports from a module. 852 853 if node.modname: 854 return "%s.%s" % (basename, node.modname), node.names 855 856 # Relative whole module imports. 857 858 else: 859 return basename, node.names 860 861 def get_argnames(args): 862 863 """ 864 Return a list of all names provided by 'args'. Since tuples may be 865 employed, the arguments are traversed depth-first. 866 """ 867 868 l = [] 869 for arg in args: 870 if isinstance(arg, tuple): 871 l += get_argnames(arg) 872 else: 873 l.append(arg) 874 return l 875 876 def get_names_from_nodes(nodes): 877 878 """ 879 Return the names employed in the given 'nodes' along with the number of 880 nodes excluding sequences. 881 """ 882 883 names = set() 884 count = 0 885 886 for node in nodes: 887 888 # Add names and count them. 889 890 if isinstance(node, (compiler.ast.AssName, compiler.ast.Name)): 891 names.add(node.name) 892 count += 1 893 894 # Add names from sequences and incorporate their counts. 895 896 elif isinstance(node, (compiler.ast.AssList, compiler.ast.AssTuple, 897 compiler.ast.List, compiler.ast.Set, 898 compiler.ast.Tuple)): 899 _names, _count = get_names_from_nodes(node.nodes) 900 names.update(_names) 901 count += _count 902 903 # Count non-name, non-sequence nodes. 904 905 else: 906 count += 1 907 908 return names, count 909 910 # Result classes. 911 912 class InstructionSequence: 913 914 "A generic sequence of instructions." 915 916 def __init__(self, instructions): 917 self.instructions = instructions 918 919 def get_value_instruction(self): 920 return self.instructions[-1] 921 922 def get_init_instructions(self): 923 return self.instructions[:-1] 924 925 # Dictionary utilities. 926 927 def init_item(d, key, fn): 928 929 """ 930 Add to 'd' an entry for 'key' using the callable 'fn' to make an initial 931 value where no entry already exists. 932 """ 933 934 if not d.has_key(key): 935 d[key] = fn() 936 return d[key] 937 938 def dict_for_keys(d, keys): 939 940 "Return a new dictionary containing entries from 'd' for the given 'keys'." 941 942 nd = {} 943 for key in keys: 944 if d.has_key(key): 945 nd[key] = d[key] 946 return nd 947 948 def make_key(s): 949 950 "Make sequence 's' into a tuple-based key, first sorting its contents." 951 952 l = list(s) 953 l.sort() 954 return tuple(l) 955 956 def add_counter_item(d, key): 957 958 """ 959 Make a mapping in 'd' for 'key' to the number of keys added before it, thus 960 maintaining a mapping of keys to their order of insertion. 961 """ 962 963 if not d.has_key(key): 964 d[key] = len(d.keys()) 965 return d[key] 966 967 def remove_items(d1, d2): 968 969 "Remove from 'd1' all items from 'd2'." 970 971 for key in d2.keys(): 972 if d1.has_key(key): 973 del d1[key] 974 975 # Set utilities. 976 977 def first(s): 978 return list(s)[0] 979 980 def same(s1, s2): 981 return set(s1) == set(s2) 982 983 def order_dependencies(all_depends): 984 985 """ 986 Produce a dependency ordering for the 'all_depends' mapping. This mapping 987 has the form "A depends on B, C...". The result will order A, B, C, and so 988 on. 989 """ 990 991 usage = init_reverse_dependencies(all_depends) 992 993 # Produce an ordering by obtaining exposed items (required by items already 994 # processed) and putting them at the start of the list. 995 996 ordered = [] 997 998 while usage: 999 have_next = False 1000 1001 for key, n in usage.items(): 1002 1003 # Add items needed by no other items to the ordering. 1004 1005 if not n: 1006 remove_dependency(key, all_depends, usage, ordered) 1007 have_next = True 1008 1009 if not have_next: 1010 raise ValueError, usage 1011 1012 return ordered 1013 1014 def order_dependencies_partial(all_depends): 1015 1016 """ 1017 Produce a dependency ordering for the 'all_depends' mapping. This mapping 1018 has the form "A depends on B, C...". The result will order A, B, C, and so 1019 on. Where cycles exist, they will be broken and a partial ordering returned. 1020 """ 1021 1022 usage = init_reverse_dependencies(all_depends) 1023 1024 # Duplicate the dependencies for subsequent modification. 1025 1026 new_depends = {} 1027 for key, values in all_depends.items(): 1028 new_depends[key] = set(values) 1029 1030 all_depends = new_depends 1031 1032 # Produce an ordering by obtaining exposed items (required by items already 1033 # processed) and putting them at the start of the list. 1034 1035 ordered = [] 1036 1037 while usage: 1038 least = None 1039 least_key = None 1040 1041 for key, n in usage.items(): 1042 1043 # Add items needed by no other items to the ordering. 1044 1045 if not n: 1046 remove_dependency(key, all_depends, usage, ordered) 1047 least = 0 1048 1049 # When breaking cycles, note the least used items. 1050 1051 elif least is None or len(n) < least: 1052 least_key = key 1053 least = len(n) 1054 1055 if least: 1056 transfer_dependencies(least_key, all_depends, usage, ordered) 1057 1058 return ordered 1059 1060 def init_reverse_dependencies(all_depends): 1061 1062 """ 1063 From 'all_depends', providing a mapping of the form "A depends on B, C...", 1064 record the reverse dependencies, making a mapping of the form 1065 "B is needed by A", "C is needed by A", and so on. 1066 """ 1067 1068 usage = {} 1069 1070 # Record path-based dependencies. 1071 1072 for key in all_depends.keys(): 1073 usage[key] = set() 1074 1075 for key, depends in all_depends.items(): 1076 for depend in depends: 1077 init_item(usage, depend, set) 1078 usage[depend].add(key) 1079 1080 return usage 1081 1082 def transfer_dependencies(key, all_depends, usage, ordered): 1083 1084 """ 1085 Transfer items needed by 'key' to those items needing 'key', found using 1086 'all_depends', and updating 'usage'. Insert 'key' into the 'ordered' 1087 collection of dependencies. 1088 1089 If "A is needed by X" and "B is needed by A", then transferring items needed 1090 by A will cause "B is needed by X" to be recorded as a consequence. 1091 1092 Transferring items also needs to occur in the reverse mapping, so that 1093 "A needs B" and "X needs A", then the consequence must be recorded as 1094 "X needs B". 1095 """ 1096 1097 ordered.insert(0, key) 1098 1099 needing = usage[key] # A is needed by X 1100 needed = all_depends.get(key) # A needs B 1101 1102 if needing: 1103 for depend in needing: 1104 l = all_depends.get(depend) 1105 if not l: 1106 continue 1107 1108 l.remove(key) # X needs (A) 1109 1110 if needed: 1111 l.update(needed) # X needs B... 1112 1113 # Prevent self references. 1114 1115 if depend in needed: 1116 l.remove(depend) 1117 1118 if needed: 1119 for depend in needed: 1120 l = usage.get(depend) 1121 if not l: 1122 continue 1123 1124 l.remove(key) # B is needed by (A) 1125 l.update(needing) # B is needed by X... 1126 1127 # Prevent self references. 1128 1129 if depend in needing: 1130 l.remove(depend) 1131 1132 if needed: 1133 del all_depends[key] 1134 del usage[key] 1135 1136 def remove_dependency(key, all_depends, usage, ordered): 1137 1138 """ 1139 Remove 'key', found in 'all_depends', from 'usage', inserting it into the 1140 'ordered' collection of dependencies. 1141 1142 Given that 'usage' for a given key A would indicate that "A needs <nothing>" 1143 upon removing A from 'usage', the outcome is that all keys needing A will 1144 have A removed from their 'usage' records. 1145 1146 So, if "B needs A", removing A will cause "B needs <nothing>" to be recorded 1147 as a consequence. 1148 """ 1149 1150 ordered.insert(0, key) 1151 1152 depends = all_depends.get(key) 1153 1154 # Reduce usage of the referenced items. 1155 1156 if depends: 1157 for depend in depends: 1158 usage[depend].remove(key) 1159 1160 del usage[key] 1161 1162 # General input/output. 1163 1164 def readfile(filename): 1165 1166 "Return the contents of 'filename'." 1167 1168 f = open(filename) 1169 try: 1170 return f.read() 1171 finally: 1172 f.close() 1173 1174 def writefile(filename, s): 1175 1176 "Write to 'filename' the string 's'." 1177 1178 f = open(filename, "w") 1179 try: 1180 f.write(s) 1181 finally: 1182 f.close() 1183 1184 # General encoding. 1185 1186 def sorted_output(x): 1187 1188 "Sort sequence 'x' and return a string with commas separating the values." 1189 1190 x = map(str, x) 1191 x.sort() 1192 return ", ".join(x) 1193 1194 def get_string_details(literals, encoding): 1195 1196 """ 1197 Determine whether 'literals' represent Unicode strings or byte strings, 1198 using 'encoding' to reproduce byte sequences. 1199 1200 Each literal is the full program representation including prefix and quotes 1201 recoded by the parser to UTF-8. Thus, any literal found to represent a byte 1202 string needs to be translated back to its original encoding. 1203 1204 Return a single encoded literal value, a type name, and the original 1205 encoding as a tuple. 1206 """ 1207 1208 typename = "unicode" 1209 1210 l = [] 1211 1212 for s in literals: 1213 out, _typename = get_literal_details(s) 1214 if _typename == "str": 1215 typename = "str" 1216 l.append(out) 1217 1218 out = "".join(l) 1219 1220 # For Unicode values, convert to the UTF-8 program representation. 1221 1222 if typename == "unicode": 1223 return out.encode("utf-8"), typename, encoding 1224 1225 # For byte string values, convert back to the original encoding. 1226 1227 else: 1228 return out.encode(encoding), typename, encoding 1229 1230 def get_literal_details(s): 1231 1232 """ 1233 Determine whether 's' represents a Unicode string or a byte string, where 1234 's' contains the full program representation of a literal including prefix 1235 and quotes, recoded by the parser to UTF-8. 1236 1237 Find and convert Unicode values starting with <backslash>u or <backslash>U, 1238 and byte or Unicode values starting with <backslash><octal digit> or 1239 <backslash>x. 1240 1241 Literals prefixed with "u" cause <backslash><octal digit> and <backslash>x 1242 to be considered as Unicode values. Otherwise, they produce byte values and 1243 cause unprefixed strings to be considered as byte strings. 1244 1245 Literals prefixed with "r" do not have their backslash-encoded values 1246 converted unless also prefixed with "u", in which case only the above value 1247 formats are converted, not any of the other special sequences for things 1248 like newlines. 1249 1250 Return the literal value as a Unicode object together with the appropriate 1251 type name in a tuple. 1252 """ 1253 1254 l = [] 1255 1256 # Identify the quote character and use it to identify the prefix. 1257 1258 quote_type = s[-1] 1259 prefix_end = s.find(quote_type) 1260 prefix = s[:prefix_end].lower() 1261 1262 if prefix not in ("", "b", "br", "r", "u", "ur"): 1263 raise ValueError, "String literal does not have a supported prefix: %s" % s 1264 1265 if "b" in prefix: 1266 typename = "str" 1267 else: 1268 typename = "unicode" 1269 1270 # Identify triple quotes or single quotes. 1271 1272 if len(s) >= 6 and s[-2] == quote_type and s[-3] == quote_type: 1273 quote = s[prefix_end:prefix_end+3] 1274 current = prefix_end + 3 1275 end = len(s) - 3 1276 else: 1277 quote = s[prefix_end] 1278 current = prefix_end + 1 1279 end = len(s) - 1 1280 1281 # Conversions of some quoted values. 1282 1283 searches = { 1284 "u" : (6, 16), 1285 "U" : (10, 16), 1286 "x" : (4, 16), 1287 } 1288 1289 octal_digits = map(str, range(0, 8)) 1290 1291 # Translations of some quoted values. 1292 1293 escaped = { 1294 "\\" : "\\", "'" : "'", '"' : '"', 1295 "a" : "\a", "b" : "\b", "f" : "\f", 1296 "n" : "\n", "r" : "\r", "t" : "\t", 1297 } 1298 1299 while current < end: 1300 1301 # Look for quoted values. 1302 1303 index = s.find("\\", current) 1304 if index == -1 or index + 1 == end: 1305 l.append(s[current:end]) 1306 break 1307 1308 # Add the preceding text. 1309 1310 l.append(s[current:index]) 1311 1312 # Handle quoted text. 1313 1314 term = s[index+1] 1315 1316 # Add Unicode values. Where a string is u-prefixed, even \o and \x 1317 # produce Unicode values. 1318 1319 if typename == "unicode" and ( 1320 term in ("u", "U") or 1321 "u" in prefix and (term == "x" or term in octal_digits)): 1322 1323 needed, base = searches.get(term, (4, 8)) 1324 value = convert_quoted_value(s, index, needed, end, base, unichr) 1325 l.append(value) 1326 current = index + needed 1327 1328 # Add raw byte values, changing the string type. 1329 1330 elif "r" not in prefix and ( 1331 term == "x" or term in octal_digits): 1332 1333 needed, base = searches.get(term, (4, 8)) 1334 value = convert_quoted_value(s, index, needed, end, base, chr) 1335 l.append(value) 1336 typename = "str" 1337 current = index + needed 1338 1339 # Add other escaped values. 1340 1341 elif "r" not in prefix and escaped.has_key(term): 1342 l.append(escaped[term]) 1343 current = index + 2 1344 1345 # Add other text as found. 1346 1347 else: 1348 l.append(s[index:index+2]) 1349 current = index + 2 1350 1351 # Collect the components into a single Unicode object. Since the literal 1352 # text was already in UTF-8 form, interpret plain strings as UTF-8 1353 # sequences. 1354 1355 out = [] 1356 1357 for value in l: 1358 if isinstance(value, unicode): 1359 out.append(value) 1360 else: 1361 out.append(unicode(value, "utf-8")) 1362 1363 return "".join(out), typename 1364 1365 def convert_quoted_value(s, index, needed, end, base, fn): 1366 1367 """ 1368 Interpret a quoted value in 's' at 'index' with the given 'needed' number of 1369 positions, and with the given 'end' indicating the first position after the 1370 end of the actual string content. 1371 1372 Use 'base' as the numerical base when interpreting the value, and use 'fn' 1373 to convert the value to an appropriate type. 1374 """ 1375 1376 s = s[index:min(index+needed, end)] 1377 1378 # Not a complete occurrence. 1379 1380 if len(s) < needed: 1381 return s 1382 1383 # Test for a well-formed value. 1384 1385 try: 1386 first = base == 8 and 1 or 2 1387 value = int(s[first:needed], base) 1388 except ValueError: 1389 return s 1390 else: 1391 return fn(value) 1392 1393 # Attribute chain decoding. 1394 1395 def get_attrnames(attrnames): 1396 1397 """ 1398 Split the qualified attribute chain 'attrnames' into its components, 1399 handling special attributes starting with "#" that indicate type 1400 conformance. 1401 """ 1402 1403 if attrnames.startswith("#"): 1404 return [attrnames] 1405 else: 1406 return attrnames.split(".") 1407 1408 def get_attrname_from_location(location): 1409 1410 """ 1411 Extract the first attribute from the attribute names employed in a 1412 'location'. 1413 """ 1414 1415 path, name, attrnames, access = location 1416 if not attrnames: 1417 return attrnames 1418 return get_attrnames(attrnames)[0] 1419 1420 def get_name_path(path, name): 1421 1422 "Return a suitable qualified name from the given 'path' and 'name'." 1423 1424 if "." in name: 1425 return name 1426 else: 1427 return "%s.%s" % (path, name) 1428 1429 # Usage-related functions. 1430 1431 def get_types_for_usage(attrnames, objects): 1432 1433 """ 1434 Identify the types that can support the given 'attrnames', using the 1435 given 'objects' as the catalogue of type details. 1436 """ 1437 1438 types = [] 1439 for name, _attrnames in objects.items(): 1440 if set(attrnames).issubset(_attrnames): 1441 types.append(name) 1442 return types 1443 1444 def get_invoked_attributes(usage): 1445 1446 "Obtain invoked attribute from the given 'usage'." 1447 1448 invoked = [] 1449 if usage: 1450 for attrname, invocation, assignment in usage: 1451 if invocation: 1452 invoked.append(attrname) 1453 return invoked 1454 1455 def get_assigned_attributes(usage): 1456 1457 "Obtain assigned attribute from the given 'usage'." 1458 1459 assigned = [] 1460 if usage: 1461 for attrname, invocation, assignment in usage: 1462 if assignment: 1463 assigned.append(attrname) 1464 return assigned 1465 1466 # Type and module functions. 1467 # NOTE: This makes assumptions about the __builtins__ structure. 1468 1469 def get_builtin_module(name): 1470 1471 "Return the module name containing the given type 'name'." 1472 1473 if name == "string": 1474 modname = "str" 1475 elif name == "utf8string": 1476 modname = "unicode" 1477 elif name == "NoneType": 1478 modname = "none" 1479 else: 1480 modname = name 1481 1482 return "__builtins__.%s" % modname 1483 1484 def get_builtin_type(name): 1485 1486 "Return the type name provided by the given Python value 'name'." 1487 1488 if name == "str": 1489 return "string" 1490 elif name == "unicode": 1491 return "utf8string" 1492 else: 1493 return name 1494 1495 def get_builtin_class(name): 1496 1497 "Return the full name of the built-in class having the given 'name'." 1498 1499 typename = get_builtin_type(name) 1500 module = get_builtin_module(typename) 1501 return "%s.%s" % (module, typename) 1502 1503 # Useful data. 1504 1505 predefined_constants = "False", "None", "NotImplemented", "True" 1506 1507 operator_functions = { 1508 1509 # Fundamental operations. 1510 1511 "is" : "is_", 1512 "is not" : "is_not", 1513 1514 # Binary operations. 1515 1516 "in" : "in_", 1517 "not in" : "not_in", 1518 "Add" : "add", 1519 "Bitand" : "and_", 1520 "Bitor" : "or_", 1521 "Bitxor" : "xor", 1522 "Div" : "div", 1523 "FloorDiv" : "floordiv", 1524 "LeftShift" : "lshift", 1525 "Mod" : "mod", 1526 "Mul" : "mul", 1527 "Power" : "pow", 1528 "RightShift" : "rshift", 1529 "Sub" : "sub", 1530 1531 # Unary operations. 1532 1533 "Invert" : "invert", 1534 "UnaryAdd" : "pos", 1535 "UnarySub" : "neg", 1536 1537 # Augmented assignment. 1538 1539 "+=" : "iadd", 1540 "-=" : "isub", 1541 "*=" : "imul", 1542 "/=" : "idiv", 1543 "//=" : "ifloordiv", 1544 "%=" : "imod", 1545 "**=" : "ipow", 1546 "<<=" : "ilshift", 1547 ">>=" : "irshift", 1548 "&=" : "iand", 1549 "^=" : "ixor", 1550 "|=" : "ior", 1551 1552 # Comparisons. 1553 1554 "==" : "eq", 1555 "!=" : "ne", 1556 "<" : "lt", 1557 "<=" : "le", 1558 ">=" : "ge", 1559 ">" : "gt", 1560 } 1561 1562 # vim: tabstop=4 expandtab shiftwidth=4