1 #!/usr/bin/env python 2 3 """ 4 Annotate program node structures. The code in this module operates upon nodes 5 which are produced when simplifying AST node trees originating from the compiler 6 module. 7 8 Copyright (C) 2006 Paul Boddie <paul@boddie.org.uk> 9 10 This software is free software; you can redistribute it and/or 11 modify it under the terms of the GNU General Public License as 12 published by the Free Software Foundation; either version 2 of 13 the License, or (at your option) any later version. 14 15 This software is distributed in the hope that it will be useful, 16 but WITHOUT ANY WARRANTY; without even the implied warranty of 17 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 18 GNU General Public License for more details. 19 20 You should have received a copy of the GNU General Public 21 License along with this library; see the file LICENCE.txt 22 If not, write to the Free Software Foundation, Inc., 23 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA 24 25 -------- 26 27 To use this module, the easiest approach is to use the load function: 28 29 load(filename, builtins) 30 31 To control module importing, an importer should be constructed and employed. 32 Here, the standard path for module searching is used: 33 34 importer = Importer(sys.path) 35 load(filename, builtins, importer) 36 37 Underneath the load function, the annotate function provides support for 38 annotating modules already processed by simplify and fixnames: 39 40 annotate(module, builtins) 41 42 And at the most basic level, the most intricate approach involves obtaining an 43 Annotator object: 44 45 annotator = Annotator() 46 47 Then, processing an existing module with it: 48 49 annotator.process(module) 50 51 If a module containing built-in classes and functions has already been 52 annotated, such a module should be passed in as an additional argument: 53 54 annotator.process(module, builtins) 55 """ 56 57 from simplified import * 58 import simplify, fixnames # for the load function 59 import compiler 60 import os 61 62 class System: 63 64 """ 65 A class maintaining the state of the annotation system. When the system 66 counter can no longer be incremented by any annotation operation, the 67 system may be considered stable and fully annotated. 68 """ 69 70 def __init__(self): 71 self.count = 0 72 73 def init(self, node): 74 75 "Initialise a 'node' for annotation." 76 77 if not hasattr(node, "types"): 78 node.types = [] 79 80 def annotate(self, node, types): 81 82 "Annotate the given 'node' with the given 'types'." 83 84 self.init(node) 85 self.combine(node.types, types) 86 87 def combine(self, target, types): 88 89 """ 90 Combine the 'target' list with the given 'types', counting new members. 91 """ 92 93 for type in types: 94 if type not in target: 95 target.append(type) 96 self.count += 1 97 98 system = System() 99 100 # Exceptions. 101 102 class AnnotationError(SimplifiedError): 103 104 "An error in the annotation process." 105 106 pass 107 108 class AnnotationMessage(Exception): 109 110 "A lesser annotation error." 111 112 pass 113 114 # Annotation. 115 116 class Annotator(Visitor): 117 118 """ 119 The type annotator which traverses the program nodes, typically depth-first, 120 and maintains a record of the current set of types applying to the currently 121 considered operation. Such types are also recorded on the nodes, and a 122 special "system" record is maintained to monitor the level of annotation 123 activity with a view to recognising when no more annotations are possible. 124 125 Throughout the annotation activity, type information consists of lists of 126 Attribute objects where such objects retain information about the context of 127 the type (since a value in the program may be associated with an object or 128 class) and the actual type of the value being manipulated. Upon accessing 129 attribute information on namespaces, additional accessor information is also 130 exchanged - this provides a means of distinguishing between the different 131 types possible when the means of constructing the namespace may depend on 132 run-time behaviour. 133 134 Covered: Assign, CheckExc, Conditional, Global, Import, InvokeBlock, 135 InvokeFunction, LoadAttr, LoadExc, LoadName, LoadRef, LoadTemp, 136 Module, Not, Pass, Raise, ReleaseTemp, ReturnFromBlock, 137 ReturnFromFunction, StoreAttr, StoreName, StoreTemp, Subprogram, 138 Try. 139 """ 140 141 def __init__(self, importer=None): 142 143 "Initialise the visitor with an optional 'importer'." 144 145 Visitor.__init__(self) 146 self.system = system 147 self.importer = importer or Importer() 148 149 # Satisfy visitor issues. 150 151 self.visitor = self 152 153 def process(self, module, builtins=None): 154 155 """ 156 Process the given 'module', using the optional 'builtins' to access 157 built-in classes and functions. 158 """ 159 160 self.subprograms = [] 161 self.current_subprograms = [] 162 self.current_namespaces = [] 163 self.namespace = None 164 self.module = module 165 166 # Give constants their own namespace. 167 168 for value, constant in module.simplifier.constants.items(): 169 constant.namespace = Namespace() 170 171 # Process the module, supplying builtins if possible. 172 173 self.builtins = builtins 174 self.global_namespace = Namespace() 175 176 if builtins is not None: 177 self.builtins_namespace = builtins.namespace 178 else: 179 self.builtins_namespace = self.global_namespace 180 181 return self.process_node(module, self.global_namespace) 182 183 def process_node(self, node, locals): 184 185 """ 186 Process a subprogram or module 'node', indicating the initial 'locals'. 187 Return an annotated subprogram or module. Note that this method may 188 mutate nodes in the original program. 189 """ 190 191 # Record the current subprogram and namespace. 192 193 self.current_subprograms.append(node) 194 195 # Determine the namespace. 196 197 self.current_namespaces.append(self.namespace) 198 self.namespace = locals 199 200 # Add namespace details to any structure involved. 201 202 if getattr(node, "structure", None) is not None: 203 node.structure.namespace = Namespace() 204 205 # Initialise bases where appropriate. 206 207 if hasattr(node.structure, "bases"): 208 base_refs = [] 209 for base in node.structure.bases: 210 self.dispatch(base) 211 base_refs.append(self.namespace.types) 212 node.structure.base_refs = base_refs 213 214 # Dispatch to the code itself. 215 216 node.namespace = self.namespace 217 result = self.dispatch(node) 218 result.namespace = self.namespace 219 220 # Obtain the return values. 221 222 self.last_returns = self.namespace.returns 223 self.last_raises = self.namespace.raises 224 self.returned_locals = self.namespace.return_locals 225 226 # Restore the previous subprogram and namespace. 227 228 self.namespace = self.current_namespaces.pop() 229 self.current_subprograms.pop() 230 231 return result 232 233 def annotate(self, node, types=None): 234 235 """ 236 Annotate the given 'node' in the system, using either the optional 237 'types' or the namespace's current type information. 238 """ 239 240 self.system.annotate(node, types or self.namespace.types) 241 242 def annotate_parameters(self, node, items): 243 244 """ 245 Annotate the given 'node' using the given 'items' and updating the 246 system's annotation counter. 247 """ 248 249 if not hasattr(node, "paramtypes"): 250 node.paramtypes = {} 251 252 for param, types in items: 253 if not node.paramtypes.has_key(param): 254 node.paramtypes[param] = [] 255 self.system.combine(node.paramtypes[param], types) 256 257 # Visitor methods. 258 259 def default(self, node): 260 261 """ 262 Process the given 'node', given that it does not have a specific 263 handler. 264 """ 265 266 raise AnnotationMessage, "Node '%s' not supported." % node 267 268 def dispatch(self, node, *args): 269 try: 270 return Visitor.dispatch(self, node, *args) 271 except AnnotationError, exc: 272 exc.add(node) 273 raise 274 except AnnotationMessage, exc: 275 raise AnnotationError(exc, node) 276 277 # Specific node methods. 278 279 def visitAssign(self, assign): 280 281 """ 282 Return the 'assign' node whose contents (merely a group of nodes) have 283 been processed. 284 """ 285 286 assign.code = self.dispatches(assign.code) 287 return assign 288 289 def visitCheckExc(self, checkexc): 290 291 """ 292 Return the 'checkexc' node, processing the expression to find the 293 possible types of the exception, and processing each choice to build a 294 list of checked types for the exception. 295 """ 296 297 checkexc.expr = self.dispatch(checkexc.expr) 298 expr_types = self.namespace.types 299 choice_types = [] 300 choices = [] 301 for choice in checkexc.choices: 302 choices.append(self.dispatch(choice)) 303 choice_types += self.namespace.types 304 for expr_type in expr_types: 305 if expr_type.type.get_class() not in choice_types: 306 self._prune_non_accesses(checkexc.expr, expr_type) 307 return checkexc 308 309 def visitConditional(self, conditional): 310 311 """ 312 Return the 'conditional' node, processing the test, body and else 313 clauses and recording their processed forms. The body and else clauses 314 are processed within their own namespaces, and the test is also 315 processed in its own namespace if 'isolate_test' is set on the 316 'conditional' node. 317 """ 318 319 # Conditionals keep local namespace changes isolated. 320 # With Return nodes inside the body/else sections, the changes are 321 # communicated to the caller. 322 323 is_module = self.namespace is self.module.namespace 324 325 # Where the test is closely associated with the body, save the namespace 326 # before entering the test. 327 328 if conditional.isolate_test: 329 saved_namespace = self.namespace 330 self.namespace = Namespace() 331 if is_module: 332 self.module.namespace = self.namespace 333 self.namespace.merge_namespace(saved_namespace) 334 335 conditional.test = self.dispatch(conditional.test) 336 337 # Where the test may affect the body and the else clause, save the 338 # namespace after processing the test. 339 340 if not conditional.isolate_test: 341 saved_namespace = self.namespace 342 self.namespace = Namespace() 343 if is_module: 344 self.module.namespace = self.namespace 345 self.namespace.merge_namespace(saved_namespace) 346 347 # Process the body clause. 348 349 conditional.body = self.dispatches(conditional.body) 350 body_namespace = self.namespace 351 352 # Use the saved namespace as a template for the else clause. 353 354 self.namespace = Namespace() 355 if is_module: 356 self.module.namespace = self.namespace 357 self.namespace.merge_namespace(saved_namespace) 358 359 # Process the else clause. 360 361 conditional.else_ = self.dispatches(conditional.else_) 362 else_namespace = self.namespace 363 364 # Merge the body and else namespaces. 365 366 self.namespace = Namespace() 367 if is_module: 368 self.module.namespace = self.namespace 369 self.namespace.merge_namespace(body_namespace) 370 self.namespace.merge_namespace(else_namespace) 371 372 # NOTE: Test of exception type pruning based on the test/body. 373 374 if conditional.isolate_test: 375 for exc_type in body_namespace.raises: 376 self.namespace.revoke_exception_type(exc_type) 377 378 return conditional 379 380 def visitGlobal(self, global_): 381 382 """ 383 Return the 'global_' node unprocessed since namespaces should have 384 already been altered to take global names into consideration. 385 """ 386 387 return global_ 388 389 def visitImport(self, import_): 390 391 """ 392 Return the 'import_' node, importing the module with the stated name 393 and storing details on the node. 394 """ 395 396 module = self.importer.load(import_.name, self.builtins, getattr(import_, "alias", None)) 397 if module is not None: 398 self.namespace.set_types([module]) 399 else: 400 self.namespace.set_types([]) 401 self.annotate(import_) # mainly for viewing purposes 402 return import_ 403 404 def _visitInvoke(self, invoke, invocation_types, have_args): 405 406 """ 407 Return the processed 'invoke' node, using the given 'invocation_types' 408 as the list of callables to be investigated for instantiation or for the 409 invocation of functions or blocks. If 'have_args' is a true value, any 410 invocation or instantiation will involve arguments. 411 """ 412 413 # Now locate and invoke the subprogram. This can be complicated because 414 # the target may be a class or object, and there may be many different 415 # related subprograms. 416 417 invocations = [] 418 419 # Visit each callable in turn, finding subprograms. 420 421 for attr in invocation_types: 422 423 # Deal with class invocations by providing instance objects. 424 # Here, each class is queried for the __init__ method, which may 425 # exist for some combinations of classes in a hierarchy but not for 426 # others. 427 428 if isinstance(attr.type, Class): 429 attributes = get_attributes(attr.type, "__init__") 430 431 # Deal with object invocations by using __call__ methods. 432 433 elif isinstance(attr.type, Instance): 434 attributes = get_attributes(attr.type, "__call__") 435 436 # Normal functions or methods are more straightforward. 437 # Here, we model them using an attribute with no context and with 438 # no associated accessor. 439 440 else: 441 attributes = [(attr, None)] 442 443 # Inspect each attribute and extract the subprogram. 444 445 for attribute, accessor in attributes: 446 447 # If a class is involved, presume that it must create a new 448 # object. 449 450 if isinstance(attr.type, Class): 451 452 # Instantiate the class. 453 # NOTE: Should probably only allocate a single instance. 454 455 instance = self.new_instance(invoke, "new", attr.type.full_name(), attr.type) 456 457 # For instantiations, switch the context. 458 459 if attribute is not None: 460 attribute = Attribute(instance, attribute.type) 461 462 # Skip cases where no callable is found. 463 464 if attribute is not None: 465 466 # If a subprogram is defined, invoke it. 467 468 self.invoke_subprogram(invoke, attribute) 469 if attribute.type not in invocations: 470 invocations.append(attribute.type) 471 472 elif not isinstance(attr.type, Class): 473 print "Invocation type is None for", accessor 474 475 else: 476 477 # Test to see if no arguments were supplied in cases where no 478 # initialiser was found. 479 480 if have_args: 481 raise AnnotationMessage, "No initialiser found for '%s' with arguments." % attr.type 482 483 # Special case: initialisation. 484 485 if isinstance(attr.type, Class): 486 487 # Associate the instance with the result of this invocation. 488 489 self.namespace.set_types([Attribute(None, instance)]) 490 self.annotate(invoke) 491 492 # Remember the invocations that were found, along with the return type 493 # information. 494 495 invoke.invocations = invocations 496 self.namespace.set_types(getattr(invoke, "types", [])) 497 return invoke 498 499 def visitInvokeBlock(self, invoke): 500 501 """ 502 Return the processed 'invoke' node, first finding the callables 503 indicated by the expression. 504 """ 505 506 invoke.expr = self.dispatch(invoke.expr) 507 invocation_types = self.namespace.types 508 return self._visitInvoke(invoke, invocation_types, have_args=0) 509 510 def visitInvokeFunction(self, invoke): 511 512 """ 513 Return the processed 'invoke' node, first finding the callables 514 indicated by the expression. 515 """ 516 517 invoke.expr = self.dispatch(invoke.expr) 518 invocation_types = self.namespace.types 519 520 # Invocation processing starts with making sure that the arguments have 521 # been processed. 522 523 return self._visitInvoke(invoke, invocation_types, have_args=self.process_args(invoke)) 524 525 def visitLoadAttr(self, loadattr): 526 527 """ 528 Return the 'loadattr' node, processing and storing the expression, and 529 using the expression's types to construct records of accesses and 530 non-accesses using the stated attribute name. 531 """ 532 533 loadattr.expr = self.dispatch(loadattr.expr) 534 types = [] 535 non_accesses = [] 536 accesses = {} 537 for attr in self.namespace.types: 538 attributes = get_attributes(attr.type, loadattr.name) 539 if not attributes: 540 if not attr in non_accesses: 541 non_accesses.append(attr) 542 combine(self.namespace.raises, self.get_builtin_instances("AttributeError")) 543 544 # Revoke this type from any name involved. 545 546 self._prune_non_accesses(loadattr.expr, attr) 547 548 for attribute, accessor in attributes: 549 if attribute is not None: 550 types.append(attribute) 551 if not accesses.has_key(attr.type): 552 accesses[attr.type] = [] 553 if not (attribute, accessor) in accesses[attr.type]: 554 accesses[attr.type].append((attribute, accessor)) 555 else: 556 if not attr in non_accesses: 557 non_accesses.append(attr) 558 combine(self.namespace.raises, self.get_builtin_instances("AttributeError")) 559 560 # Revoke this type from any name involved. 561 562 self._prune_non_accesses(loadattr.expr, attr) 563 564 if not types: 565 print "No attribute found for", loadattr.name, "given", self.namespace.types 566 self.namespace.set_types(types) 567 loadattr.non_accesses = non_accesses 568 loadattr.accesses = accesses 569 self.annotate(loadattr) 570 return loadattr 571 572 def _prune_non_accesses(self, expr, attr): 573 574 """ 575 Prune type information from 'expr' where the given 'attr' has been 576 shown to be a non-access. 577 """ 578 579 if isinstance(expr, LoadName): 580 self.namespace.revoke(expr.name, attr) 581 elif isinstance(expr, LoadExc): 582 self.namespace.revoke_exception_type(attr) 583 elif isinstance(expr, LoadTemp): 584 self.namespace.revoke_temp_type(getattr(expr, "index", None), attr) 585 586 # LoadAttr cannot be pruned since this might unintentionally prune 587 # legitimate types from other applications of the referenced type, it 588 # almost certainly doesn't take "concurrent" mutation into 589 # consideration (where in a running program, the pruned type is actually 590 # reintroduced, making the pruning invalid), and there is no easy way of 591 # preserving the meaning of a namespace without either creating lots of 592 # specialised instances, and even then... 593 594 #elif isinstance(expr, LoadAttr): 595 # for expr_attr in expr.expr.types: 596 # if hasattr(expr_attr.type, "namespace"): 597 # expr_attr.type.namespace.revoke(expr.name, attr) 598 599 def visitLoadExc(self, loadexc): 600 601 """ 602 Return the 'loadexc' node, discovering the possible exception types 603 raised. 604 """ 605 606 self.namespace.set_types(self.namespace.raises[:]) 607 self.annotate(loadexc) 608 return loadexc 609 610 def visitLoadName(self, loadname): 611 612 """ 613 Return the 'loadname' node, processing the name information on the node 614 to determine which types are involved with the name. 615 """ 616 617 self.namespace.set_types(self.namespace.load(loadname.name)) 618 result = loadname 619 self.annotate(result) 620 return result 621 622 def visitLoadRef(self, loadref): 623 624 """ 625 Return the 'loadref' node, obtaining type information about the 626 reference stated on the node. 627 """ 628 629 self.namespace.set_types([Attribute(None, loadref.ref)]) 630 self.annotate(loadref) 631 return loadref 632 633 def visitLoadTemp(self, loadtemp): 634 635 """ 636 Return the 'loadtemp' node, obtaining type information about the 637 temporary variable accessed, and removing variable information where the 638 'release' attribute has been set on the node. 639 """ 640 641 index = getattr(loadtemp, "index", None) 642 try: 643 if getattr(loadtemp, "release", 0): 644 self.namespace.set_types(self.namespace.temp[index].pop()) 645 else: 646 self.namespace.set_types(self.namespace.temp[index][-1]) 647 except KeyError: 648 raise AnnotationMessage, "Temporary store index '%s' not defined." % index 649 self.annotate(loadtemp) 650 return loadtemp 651 652 def visitModule(self, module): 653 654 """ 655 Return the processed 'module' whose contents (merely a group of nodes) 656 are processed. 657 """ 658 659 module.code = self.dispatches(module.code) 660 return module 661 662 def visitNot(self, not_): 663 664 "Return the 'not_' node whose expression is processed." 665 666 not_.expr = self.dispatch(not_.expr) 667 return not_ 668 669 def visitPass(self, pass_): 670 671 "Return the unprocessed 'pass_' node." 672 673 return pass_ 674 675 def visitRaise(self, raise_): 676 677 """ 678 Return the 'raise_' node, processing any traceback information along 679 with the raised exception expression, converting the node into a kind of 680 invocation where the expression is found not to be an invocation itself. 681 This node affects the namespace, adding exception types to the list of 682 those raised in the namespace. 683 """ 684 685 if getattr(raise_, "traceback", None) is not None: 686 raise_.traceback = self.dispatch(raise_.traceback) 687 raise_.expr = self.dispatch(raise_.expr) 688 689 # Handle bare name exceptions by converting any classes to instances. 690 691 if not isinstance(raise_.expr, InvokeFunction): 692 raise_.pos_args = [] 693 raise_.kw_args = {} 694 raise_.star = None 695 raise_.dstar = None 696 types = [] 697 for attr in self.namespace.types: 698 if isinstance(attr.type, Class): 699 self._visitInvoke(raise_, [attr], have_args=0) 700 types += self.namespace.types 701 else: 702 types = self.namespace.types 703 704 combine(self.namespace.raises, types) 705 return raise_ 706 707 def visitReleaseTemp(self, releasetemp): 708 709 """ 710 Return the 'releasetemp' node, removing temporary variable information 711 from the current namespace. 712 """ 713 714 index = getattr(releasetemp, "index", None) 715 try: 716 self.namespace.temp[index].pop() 717 except KeyError: 718 raise AnnotationMessage, "Temporary store index '%s' not defined." % index 719 except IndexError: 720 pass #raise AnnotationMessage, "Temporary store index '%s' is empty." % index 721 return releasetemp 722 723 def visitReturn(self, return_): 724 725 """ 726 Return the 'return_' node, processing any expression and obtaining type 727 information to be accumulated in the current namespace's list of return 728 types. A snapshot of the namespace is taken for the purposes of 729 reconciling or merging namespaces where subprograms actually share 730 locals with their callers. 731 """ 732 733 if hasattr(return_, "expr"): 734 return_.expr = self.dispatch(return_.expr) 735 combine(self.namespace.returns, self.namespace.types) 736 self.annotate(return_) 737 self.namespace.snapshot() 738 return return_ 739 740 visitReturnFromBlock = visitReturn 741 visitReturnFromFunction = visitReturn 742 743 def visitStoreAttr(self, storeattr): 744 745 """ 746 Return the 'storeattr' node, processing the expression and target, and 747 using the type information obtained to build records of legitimate 748 writes to the stated attribute, along with "impossible" non-writes to 749 the attribute. 750 """ 751 752 storeattr.expr = self.dispatch(storeattr.expr) 753 expr = self.namespace.types 754 storeattr.lvalue = self.dispatch(storeattr.lvalue) 755 writes = {} 756 non_writes = [] 757 for attr in self.namespace.types: 758 # NOTE: Impose "atomic" constraints on certain types. 759 if attr is None: 760 if not attr in non_writes: 761 non_writes.append(attr) 762 continue 763 attr.type.namespace.add(storeattr.name, expr) 764 writes[attr.type] = attr.type.namespace.load(storeattr.name) 765 if not writes: 766 print "Unable to store attribute", storeattr.name, "given", self.namespace.types 767 storeattr.writes = writes 768 storeattr.non_writes = non_writes 769 return storeattr 770 771 def visitStoreName(self, storename): 772 773 """ 774 Return the 'storename' node, processing the expression on the node and 775 associating the type information obtained with the stated name in the 776 current namespace. 777 """ 778 779 storename.expr = self.dispatch(storename.expr) 780 self.namespace.store(storename.name, self.namespace.types) 781 return storename 782 783 def visitStoreTemp(self, storetemp): 784 785 """ 786 Return the 'storetemp' node, processing the expression on the node and 787 associating the type information obtained with a temporary variable in 788 the current namespace. 789 """ 790 791 storetemp.expr = self.dispatch(storetemp.expr) 792 index = getattr(storetemp, "index", None) 793 if not self.namespace.temp.has_key(index): 794 self.namespace.temp[index] = [] 795 self.namespace.temp[index].append(self.namespace.types) 796 return storetemp 797 798 def visitSubprogram(self, subprogram): 799 800 """ 801 Return the 'subprogram' node, processing its contents (a group of nodes 802 comprising the subprogram). 803 """ 804 805 subprogram.code = self.dispatches(subprogram.code) 806 return subprogram 807 808 def visitTry(self, try_): 809 810 """ 811 Return the 'try_' node, processing the body clause in its own namespace 812 derived from the current namespace, processing any handler clause using 813 the namespace information accumulated in the body, and processing any 814 else and finally clauses, attempting to supply each with appropriate 815 namespace information. 816 """ 817 818 is_module = self.namespace is self.module.namespace 819 820 try_.body = self.dispatches(try_.body) 821 822 # Save the namespace from the body. 823 824 body_namespace = Namespace() 825 body_namespace.merge_namespace(self.namespace) 826 827 # Process the handler. 828 829 if hasattr(try_, "handler"): 830 try_.handler = self.dispatches(try_.handler) 831 832 # Save the namespace from the handler. 833 834 handler_namespace = Namespace() 835 handler_namespace.merge_namespace(self.namespace) 836 837 # Remember the raised exceptions encountered so far. 838 839 raises = self.namespace.raises 840 841 # Process the else clause. 842 843 if hasattr(try_, "else_"): 844 845 # Restore the body namespace for the else clause. 846 847 self.namespace = body_namespace 848 if is_module: 849 self.module.namespace = self.namespace 850 851 # Empty the raised exceptions for the else clause. 852 853 self.namespace.raises = [] 854 try_.else_ = self.dispatches(try_.else_) 855 self.namespace.raises = raises 856 857 # Merge the namespaces. 858 859 self.namespace = Namespace() 860 if is_module: 861 self.module.namespace = self.namespace 862 self.namespace.merge_namespace(body_namespace) 863 self.namespace.merge_namespace(handler_namespace) 864 865 # Process the finally clause, if any. 866 867 try_.finally_ = self.dispatches(try_.finally_) 868 return try_ 869 870 # Utility methods. 871 872 def get_builtin_instances(self, name): 873 return [Attribute(None, self._new_instance(attr.type)) for attr in self.builtins.namespace[name]] 874 875 def new_instance(self, node, reason, target, type): 876 877 "Create, on the given 'node', a new instance with the given 'type'." 878 879 if not hasattr(node, "instances"): 880 node.instances = {} 881 882 if not node.instances.has_key((reason, target, type)): 883 instance = self._new_instance(type) 884 node.instances[(reason, target, type)] = instance 885 886 return node.instances[(reason, target, type)] 887 888 def _new_instance(self, type): 889 890 # Insist on a single instance per type. 891 # NOTE: Strategy-dependent instantiation. 892 893 if len(type.instances) == 0: 894 instance = Instance() 895 instance.namespace = Namespace() 896 instance.namespace.store("__class__", [Attribute(None, type)]) 897 type.instances.append(instance) 898 else: 899 instance = type.instances[0] 900 901 return instance 902 903 def invoke_subprogram(self, invoke, attribute): 904 905 """ 906 Invoke using the given 'invoke' node the subprogram represented by the 907 given 'attribute'. 908 """ 909 910 # Test for context information, making it into a real attribute. 911 912 if attribute.context is not None: 913 context = Attribute(None, attribute.context) 914 target = attribute.type 915 else: 916 context = None 917 target = attribute.type 918 919 # Test to see if anything has changed. 920 921 if hasattr(invoke, "syscount") and invoke.syscount == self.system.count: 922 return 923 924 # Remember the state of the system. 925 926 else: 927 invoke.syscount = self.system.count 928 929 # Provide the correct namespace for the invocation. 930 # This may be a "shared" namespace... 931 932 if getattr(invoke, "share_locals", 0): 933 namespace = Namespace() 934 namespace.merge_namespace(self.namespace, everything=0) 935 using_module_namespace = self.namespace is self.module.namespace 936 937 # Or it may be a structure... 938 939 elif getattr(target, "structure", None): 940 namespace = Namespace() 941 using_module_namespace = 0 942 943 # Or it may be a new namespace populated with the supplied parameters. 944 945 else: 946 items = self.make_items(invoke, target, context) 947 namespace = Namespace() 948 namespace.merge_items(items) 949 using_module_namespace = 0 950 951 # Process the subprogram. 952 # In order to keep global accesses working, the module namespace must be 953 # adjusted. 954 955 if using_module_namespace: 956 self.module.namespace = namespace 957 958 self.process_node(target, namespace) 959 960 # NOTE: Improve and verify this. 961 # If the invocation returns a value, acquire the return types. 962 963 if getattr(target, "returns_value", 0): 964 self.namespace.set_types(self.last_returns) 965 self.annotate(invoke) 966 967 # If it is a normal block, merge the locals. 968 # This can happen in addition to the above because for things like 969 # logical expressions, the namespace can be modified whilst values are 970 # returned as results. 971 972 if getattr(invoke, "share_locals", 0): 973 self.namespace.reset() 974 975 # Merge the locals snapshots. 976 977 for locals in self.returned_locals: 978 979 # For blocks returning values (such as operations), do not merge 980 # snapshots or results. 981 982 if getattr(target, "returns_value", 0): 983 self.namespace.merge_namespace(locals, everything=0) 984 985 # For blocks not returning values (such as loops), merge 986 # snapshots and results since they contain details of genuine 987 # returns. 988 989 else: 990 self.namespace.merge_namespace(locals) 991 992 # Incorporate any raised exceptions. 993 994 combine(self.namespace.raises, self.last_raises) 995 996 # In order to keep global accesses working, the module namespace must be 997 # adjusted. 998 999 if using_module_namespace: 1000 self.module.namespace = self.namespace 1001 1002 def process_args(self, invocation): 1003 1004 """ 1005 Process the arguments associated with an 'invocation'. Return whether 1006 any arguments were processed. 1007 """ 1008 1009 invocation.pos_args = self.dispatches(invocation.pos_args) 1010 invocation.kw_args = self.dispatch_dict(invocation.kw_args) 1011 1012 # Get type information for star and dstar arguments. 1013 1014 if invocation.star is not None: 1015 param, default = invocation.star 1016 default = self.dispatch(default) 1017 invocation.star = param, default 1018 1019 if invocation.dstar is not None: 1020 param, default = invocation.dstar 1021 default = self.dispatch(default) 1022 invocation.dstar = param, default 1023 1024 if invocation.pos_args or invocation.kw_args or invocation.star or invocation.dstar: 1025 return 1 1026 else: 1027 return 0 1028 1029 def make_items(self, invocation, subprogram, context): 1030 1031 """ 1032 Make an items mapping for the 'invocation' of the 'subprogram' using the 1033 given 'context' (which may be None). 1034 """ 1035 1036 if context is not None: 1037 pos_args = [Self(context)] + invocation.pos_args 1038 else: 1039 pos_args = invocation.pos_args 1040 1041 # Duplicate the keyword arguments - we remove them in processing below. 1042 1043 kw_args = {} 1044 kw_args.update(invocation.kw_args) 1045 1046 # Sort the arguments into positional and keyword arguments. 1047 1048 params = subprogram.params 1049 items = [] 1050 star_args = [] 1051 1052 # Match each positional argument, taking excess arguments as star args. 1053 1054 for arg in pos_args: 1055 if params: 1056 param, default = params[0] 1057 if arg is None: 1058 arg = default 1059 if hasattr(arg, "types"): 1060 items.append((param, arg.types)) 1061 else: 1062 items.append((param, [])) # Annotation has not succeeded. 1063 params = params[1:] 1064 else: 1065 star_args.append(arg) 1066 1067 # Collect the remaining defaults. 1068 1069 while params: 1070 param, default = params[0] 1071 if kw_args.has_key(param): 1072 arg = kw_args[param] 1073 del kw_args[param] 1074 elif default is not None: 1075 arg = self.dispatch(default) 1076 else: 1077 raise AnnotationMessage, "No argument supplied in '%s' for parameter '%s'." % (subprogram, param) 1078 if hasattr(arg, "types"): 1079 items.append((param, arg.types)) 1080 else: 1081 items.append((param, [])) # Annotation has not succeeded. 1082 params = params[1:] 1083 1084 dstar_args = kw_args.items() 1085 1086 # Construct temporary objects. 1087 1088 if star_args: 1089 star_invocation = self.make_star_args(invocation, subprogram, star_args) 1090 self.dispatch(star_invocation) 1091 star_types = star_invocation.types 1092 else: 1093 star_types = None 1094 1095 if dstar_args: 1096 dstar_invocation = self.make_dstar_args(invocation, subprogram, dstar_args) 1097 self.dispatch(dstar_invocation) 1098 dstar_types = dstar_invocation.types 1099 else: 1100 dstar_types = None 1101 1102 # NOTE: Merge the objects properly. 1103 1104 star_types = star_types or invocation.star and invocation.star.types 1105 dstar_types = dstar_types or invocation.dstar and invocation.dstar.types 1106 1107 # Add star and dstar. 1108 1109 if star_types is not None: 1110 if subprogram.star is not None: 1111 param, default = subprogram.star 1112 items.append((param, star_types)) 1113 else: 1114 raise AnnotationMessage, "Invocation provides unwanted *args." 1115 elif subprogram.star is not None: 1116 param, default = subprogram.star 1117 if not hasattr(default, "types"): 1118 subprogram.star = param, self.dispatch(default) # NOTE: Review reprocessing. 1119 items.append((param, default.types)) 1120 1121 if dstar_types is not None: 1122 if subprogram.dstar is not None: 1123 param, default = subprogram.dstar 1124 items.append((param, dstar_types)) 1125 else: 1126 raise AnnotationMessage, "Invocation provides unwanted **args." 1127 elif subprogram.dstar is not None: 1128 param, default = subprogram.dstar 1129 if not hasattr(default, "types"): 1130 subprogram.dstar = param, self.dispatch(default) # NOTE: Review reprocessing. 1131 items.append((param, default.types)) 1132 1133 # Record the parameter types. 1134 1135 self.annotate_parameters(subprogram, items) 1136 return subprogram.paramtypes.items() 1137 1138 def make_star_args(self, invocation, subprogram, star_args): 1139 1140 "Make a subprogram which initialises a list containing 'star_args'." 1141 1142 if not hasattr(invocation, "stars"): 1143 invocation.stars = {} 1144 1145 if not invocation.stars.has_key(subprogram.full_name()): 1146 code=[ 1147 StoreTemp( 1148 expr=InvokeFunction( 1149 expr=LoadAttr( 1150 expr=LoadRef( 1151 ref=self.builtins 1152 ), 1153 name="list", 1154 nstype="module", 1155 ), 1156 args=[], 1157 star=None, 1158 dstar=None 1159 ) 1160 ) 1161 ] 1162 1163 for arg in star_args: 1164 code.append( 1165 InvokeFunction( 1166 expr=LoadAttr( 1167 expr=LoadTemp(), 1168 name="append" 1169 ), 1170 args=[arg], 1171 star=None, 1172 dstar=None 1173 ) 1174 ) 1175 1176 code += [ 1177 Return(expr=LoadTemp(release=1)) 1178 ] 1179 1180 invocation.stars[subprogram.full_name()] = InvokeBlock( 1181 produces_result=1, 1182 expr=LoadRef( 1183 ref=Subprogram( 1184 name=None, 1185 returns_value=1, 1186 params=[], 1187 star=None, 1188 dstar=None, 1189 code=code 1190 ) 1191 ) 1192 ) 1193 1194 return invocation.stars[subprogram.full_name()] 1195 1196 def make_dstar_args(self, invocation, subprogram, dstar_args): 1197 1198 """ 1199 Make a subprogram which initialises a dictionary built from the given 1200 'dstar_args'. 1201 """ 1202 1203 if not hasattr(invocation, "dstars"): 1204 invocation.dstars = {} 1205 1206 if not invocation.dstars.has_key(subprogram.full_name()): 1207 code=[ 1208 StoreTemp( 1209 expr=InvokeFunction( 1210 expr=LoadAttr( 1211 expr=LoadRef( 1212 ref=self.builtins 1213 ), 1214 name="dict", 1215 nstype="module", 1216 ) 1217 ) 1218 ) 1219 ] 1220 1221 for arg, value in dstar_args: 1222 1223 # NOTE: Constant not added to table. 1224 1225 constant = Constant(name=repr(arg), value=arg, namespace=Namespace()) 1226 code += [ 1227 StoreTemp( 1228 expr=LoadRef( 1229 ref=constant 1230 ), 1231 index="const" 1232 ), 1233 StoreAttr( 1234 lvalue=LoadTemp( 1235 index="const" 1236 ), 1237 name="__class__", 1238 expr=LoadAttr( 1239 expr=LoadRef( 1240 ref=self.builtins 1241 ), 1242 name=constant.typename, 1243 nstype="module", 1244 ) 1245 ), 1246 InvokeFunction( 1247 expr=LoadAttr( 1248 expr=LoadTemp(), 1249 name="__setitem__" 1250 ), 1251 args=[ 1252 LoadTemp( 1253 index="const", 1254 release=1 1255 ), 1256 value 1257 ] 1258 ) 1259 ] 1260 1261 code += [ 1262 Return(expr=LoadTemp(release=1)) 1263 ] 1264 1265 invocation.dstars[subprogram.full_name()] = InvokeBlock( 1266 produces_result=1, 1267 expr=LoadRef( 1268 ref=Subprogram( 1269 name=None, 1270 returns_value=1, 1271 params=[], 1272 star=None, 1273 dstar=None, 1274 code=code 1275 ) 1276 ) 1277 ) 1278 1279 return invocation.dstars[subprogram.full_name()] 1280 1281 # Namespace-related abstractions. 1282 1283 class Namespace: 1284 1285 """ 1286 A local namespace which may either relate to a genuine set of function 1287 locals or the initialisation of a structure or module. 1288 """ 1289 1290 def __init__(self): 1291 1292 """ 1293 Initialise the namespace with a mapping of local names to possible 1294 types, a list of return values and of possible returned local 1295 namespaces. The namespace also tracks the "current" types and a mapping 1296 of temporary value names to types. 1297 """ 1298 1299 self.names = {} 1300 self.returns = [] 1301 self.return_locals = [] 1302 self.raises = [] 1303 self.temp = {} 1304 self.types = [] 1305 1306 def set_types(self, types): 1307 1308 "Set the current collection of 'types'." 1309 1310 self.types = types 1311 1312 def add(self, name, types): 1313 1314 "Add to the entry with the given 'name' the specified 'types'." 1315 1316 if self.names.has_key(name): 1317 combine(self.names[name], types) 1318 else: 1319 self.store(name, types) 1320 1321 def store(self, name, types): 1322 1323 "Store in (or associate with) the given 'name' the specified 'types'." 1324 1325 self.names[name] = types 1326 1327 __setitem__ = store 1328 1329 def load(self, name): 1330 1331 "Load the types associated with the given 'name'." 1332 1333 return self.names[name] 1334 1335 __getitem__ = load 1336 1337 def revoke(self, name, type): 1338 1339 "Revoke from the entry for the given 'name' the specified 'type'." 1340 1341 new_types = self.names[name][:] 1342 new_types.remove(type) 1343 self.names[name] = new_types 1344 1345 def revoke_exception_type(self, type): 1346 1347 "Revoke the given 'type' from the collection of exception types." 1348 1349 self.raises.remove(type) 1350 1351 def revoke_temp_type(self, index, type): 1352 1353 "Revoke from the temporary variable 'index' the given 'type'." 1354 1355 new_types = self.temp[index][-1][:] 1356 new_types.remove(type) 1357 self.temp[index][-1] = new_types 1358 1359 def merge_namespace(self, namespace, everything=1): 1360 1361 """ 1362 Merge items from the given 'namespace' with this namespace. When the 1363 optional 'everything' parameter is set to a false value (unlike the 1364 default), return values and locals snapshots will not be copied to this 1365 namespace. 1366 """ 1367 1368 self.merge_items(namespace.names.items()) 1369 if everything: 1370 combine(self.returns, namespace.returns) 1371 combine(self.return_locals, namespace.return_locals) 1372 combine(self.raises, namespace.raises) 1373 for name, values in namespace.temp.items(): 1374 if values: 1375 if not self.temp.has_key(name) or not self.temp[name]: 1376 self.temp[name] = [[]] 1377 combine(self.temp[name][-1], values[-1]) 1378 1379 def merge_items(self, items): 1380 1381 "Merge the given 'items' with this namespace." 1382 1383 for name, types in items: 1384 self.merge(name, types) 1385 1386 def merge(self, name, types): 1387 1388 "Merge the entry for the given 'name' and 'types' with this namespace." 1389 1390 if not self.names.has_key(name): 1391 self.names[name] = types[:] 1392 else: 1393 existing = self.names[name] 1394 combine(existing, types) 1395 1396 def snapshot(self): 1397 1398 "Make a snapshot of the locals and remember them." 1399 1400 namespace = Namespace() 1401 namespace.merge_namespace(self) 1402 self.return_locals.append(namespace) 1403 1404 def reset(self): 1405 1406 "Reset a namespace in preparation for merging with returned locals." 1407 1408 self.names = {} 1409 1410 def __repr__(self): 1411 return repr(self.names) 1412 1413 class Attribute: 1414 1415 """ 1416 An attribute abstraction, indicating the type of the attribute along with 1417 its context or origin. 1418 """ 1419 1420 def __init__(self, context, type): 1421 self.context = context 1422 self.type = type 1423 1424 def __eq__(self, other): 1425 return hasattr(other, "type") and other.type == self.type or other == self.type 1426 1427 def __repr__(self): 1428 return "Attribute(%s, %s)" % (repr(self.context), repr(self.type)) 1429 1430 class Self: 1431 1432 """ 1433 A program node encapsulating object/context information in an argument list. 1434 This is not particularly like Attribute, Class, Instance or other such 1435 things, since it actually appears in the program representation. 1436 """ 1437 1438 def __init__(self, attribute): 1439 self.types = [attribute] 1440 1441 class Importer: 1442 1443 "An import machine, searching for and loading modules." 1444 1445 def __init__(self, path=None): 1446 1447 """ 1448 Initialise the importer with the given search 'path' - a list of 1449 directories to search for Python modules. 1450 """ 1451 1452 self.path = path or [os.getcwd()] 1453 self.modules = {} 1454 1455 def find_in_path(self, name): 1456 1457 """ 1458 Find the given module 'name' in the search path, returning None where no 1459 such module could be found, or a 2-tuple from the 'find' method 1460 otherwise. 1461 """ 1462 1463 for d in self.path: 1464 m = self.find(d, name) 1465 if m: return m 1466 return None 1467 1468 def find(self, d, name): 1469 1470 """ 1471 In the directory 'd', find the given module 'name', where 'name' can 1472 either refer to a single file module or to a package. Return None if the 1473 'name' cannot be associated with either a file or a package directory, 1474 or a 2-tuple from '_find_package' or '_find_module' otherwise. 1475 """ 1476 1477 m = self._find_package(d, name) 1478 if m: return m 1479 m = self._find_module(d, name) 1480 if m: return m 1481 return None 1482 1483 def _find_module(self, d, name): 1484 1485 """ 1486 In the directory 'd', find the given module 'name', returning None where 1487 no suitable file exists in the directory, or a 2-tuple consisting of 1488 None (indicating that no package directory is involved) and a filename 1489 indicating the location of the module. 1490 """ 1491 1492 name_py = name + os.extsep + "py" 1493 filename = self._find_file(d, name_py) 1494 if filename: 1495 return None, filename 1496 return None 1497 1498 def _find_package(self, d, name): 1499 1500 """ 1501 In the directory 'd', find the given package 'name', returning None 1502 where no suitable package directory exists, or a 2-tuple consisting of 1503 a directory (indicating the location of the package directory itself) 1504 and a filename indicating the location of the __init__.py module which 1505 declares the package's top-level contents. 1506 """ 1507 1508 filename = self._find_file(d, name) 1509 if filename: 1510 init_py = "__init__" + os.path.extsep + "py" 1511 init_py_filename = self._find_file(filename, init_py) 1512 if init_py_filename: 1513 return filename, init_py_filename 1514 return None 1515 1516 def _find_file(self, d, filename): 1517 1518 """ 1519 Return the filename obtained when searching the directory 'd' for the 1520 given 'filename', or None if no actual file exists for the filename. 1521 """ 1522 1523 filename = os.path.join(d, filename) 1524 if os.path.exists(filename): 1525 return filename 1526 else: 1527 return None 1528 1529 def load(self, name, builtins, alias=None): 1530 1531 """ 1532 Load the module or package with the given 'name' and using the specified 1533 'builtins'. Return an Attribute object referencing the loaded module or 1534 package, or None if no such module or package exists. 1535 """ 1536 1537 path = name.split(".") 1538 m = self.find_in_path(path[0]) 1539 if not m: 1540 return None # NOTE: Import error. 1541 d, filename = m 1542 top = module = self.modules.get(path[0], load(filename, builtins, path[0], self)) 1543 self.modules[path[0]] = module 1544 1545 if len(path) > 1: 1546 path_so_far = path[:1] 1547 for p in path[1:]: 1548 path_so_far.append(p) 1549 m = self.find(d, p) 1550 if not m: 1551 return None # NOTE: Import error. 1552 d, filename = m 1553 module_name = ".".join(path_so_far) 1554 submodule = self.modules.get(module_name, load(filename, builtins, module_name, self)) 1555 self.modules[module_name] = submodule 1556 1557 # Store the submodule within its parent module. 1558 1559 module.namespace[p] = [Attribute(None, submodule)] 1560 module = submodule 1561 1562 if alias: 1563 return Attribute(None, module) 1564 else: 1565 return Attribute(None, top) 1566 1567 def combine(target, additions): 1568 1569 """ 1570 Merge into the 'target' sequence the given 'additions', preventing duplicate 1571 items. 1572 """ 1573 1574 for addition in additions: 1575 if addition not in target: 1576 target.append(addition) 1577 1578 def find_attributes(structure, name): 1579 1580 """ 1581 Find for the given 'structure' all attributes for the given 'name', visiting 1582 base classes where appropriate and returning the attributes in order of 1583 descending precedence for all possible base classes. 1584 1585 The elements in the result list are 2-tuples which contain the attribute and 1586 the structure involved in accessing the attribute. 1587 """ 1588 1589 # First attempt to search the instance/class namespace. 1590 1591 try: 1592 l = structure.namespace.load(name) 1593 attributes = [] 1594 for attribute in l: 1595 attributes.append((attribute, structure)) 1596 1597 # If that does not work, attempt to investigate any class or base classes. 1598 1599 except KeyError: 1600 attributes = [] 1601 1602 # Investigate any instance's implementing class. 1603 1604 if isinstance(structure, Instance): 1605 for attr in structure.namespace.load("__class__"): 1606 cls = attr.type 1607 l = get_attributes(cls, name) 1608 combine(attributes, l) 1609 1610 # Investigate any class's base classes. 1611 1612 elif isinstance(structure, Class): 1613 1614 # If no base classes exist, return an indicator that no attribute 1615 # exists. 1616 1617 if not structure.base_refs: 1618 return [(None, structure)] 1619 1620 # Otherwise, find all possible base classes. 1621 1622 for base_refs in structure.base_refs: 1623 base_attributes = [] 1624 1625 # For each base class, find attributes either in the base 1626 # class or its own base classes. 1627 1628 for base_ref in base_refs: 1629 l = get_attributes(base_ref, name) 1630 combine(base_attributes, l) 1631 1632 combine(attributes, base_attributes) 1633 1634 return attributes 1635 1636 def get_attributes(structure, name): 1637 1638 """ 1639 Return all possible attributes for the given 'structure' having the given 1640 'name', wrapping each attribute in an Attribute object which includes 1641 context information for the attribute access. 1642 1643 The elements in the result list are 2-tuples which contain the attribute and 1644 the structure involved in accessing the attribute. 1645 """ 1646 1647 if isinstance(structure, Attribute): 1648 structure = structure.type 1649 results = [] 1650 for attribute, accessor in find_attributes(structure, name): 1651 if attribute is not None and isinstance(structure, Structure): 1652 results.append((Attribute(structure, attribute.type), accessor)) 1653 else: 1654 results.append((attribute, accessor)) 1655 return results 1656 1657 # Convenience functions. 1658 1659 def load(name, builtins=None, module_name=None, importer=None): 1660 1661 """ 1662 Load the module with the given 'name' (which may be a full module path), 1663 using the optional 'builtins' to resolve built-in names, and using the 1664 optional 'importer' to provide a means of finding and loading modules. 1665 """ 1666 1667 module = simplify.simplify(name, builtins is None, module_name) 1668 fixnames.fix(module, builtins) 1669 annotate(module, builtins, importer) 1670 return module 1671 1672 def annotate(module, builtins=None, importer=None): 1673 1674 """ 1675 Annotate the given 'module', also employing the optional 'builtins' module, 1676 if specified. If the optional 'importer' is given, use that to find and load 1677 modules. 1678 """ 1679 1680 annotator = Annotator(importer) 1681 if builtins is not None: 1682 annotator.process(module, builtins) 1683 else: 1684 annotator.process(module) 1685 1686 # vim: tabstop=4 expandtab shiftwidth=4