SCons.Node

173 """The base Node class, for entities that we know how to 174 build, or use to build other Nodes. 175 """ 176 177 if SCons.Memoize.use_memoizer: 178 __metaclass__ = SCons.Memoize.Memoized_Metaclass 179 180 memoizer_counters = [] 181

182 - class Attrs(object):

183 pass

184

185 - def __init__(self):

186 if __debug__: logInstanceCreation(self, 'Node.Node') 187 # Note that we no longer explicitly initialize a self.builder 188 # attribute to None here. That's because the self.builder 189 # attribute may be created on-the-fly later by a subclass (the 190 # canonical example being a builder to fetch a file from a 191 # source code system like CVS or Subversion). 192 193 # Each list of children that we maintain is accompanied by a 194 # dictionary used to look up quickly whether a node is already 195 # present in the list. Empirical tests showed that it was 196 # fastest to maintain them as side-by-side Node attributes in 197 # this way, instead of wrapping up each list+dictionary pair in 198 # a class. (Of course, we could always still do that in the 199 # future if we had a good reason to...). 200 self.sources = [] # source files used to build node 201 self.sources_set = set() 202 self._specific_sources = False 203 self.depends = [] # explicit dependencies (from Depends) 204 self.depends_set = set() 205 self.ignore = [] # dependencies to ignore 206 self.ignore_set = set() 207 self.prerequisites = SCons.Util.UniqueList() 208 self.implicit = None # implicit (scanned) dependencies (None means not scanned yet) 209 self.waiting_parents = set() 210 self.waiting_s_e = set() 211 self.ref_count = 0 212 self.wkids = None # Kids yet to walk, when it's an array 213 214 self.env = None 215 self.state = no_state 216 self.precious = None 217 self.noclean = 0 218 self.nocache = 0 219 self.always_build = None 220 self.includes = None 221 self.attributes = self.Attrs() # Generic place to stick information about the Node. 222 self.side_effect = 0 # true iff this node is a side effect 223 self.side_effects = [] # the side effects of building this target 224 self.linked = 0 # is this node linked to the variant directory? 225 226 self.clear_memoized_values() 227 228 # Let the interface in which the build engine is embedded 229 # annotate this Node with its own info (like a description of 230 # what line in what file created the node, for example). 231 Annotate(self)

232

233 - def disambiguate(self, must_exist=None):

234 return self

235

236 - def get_suffix(self):

237 return ''

238 239 memoizer_counters.append(SCons.Memoize.CountValue('get_build_env')) 240

241 - def get_build_env(self):

242 """Fetch the appropriate Environment to build this node. 243 """ 244 try: 245 return self._memo['get_build_env'] 246 except KeyError: 247 pass 248 result = self.get_executor().get_build_env() 249 self._memo['get_build_env'] = result 250 return result

251

252 - def get_build_scanner_path(self, scanner):

253 """Fetch the appropriate scanner path for this node.""" 254 return self.get_executor().get_build_scanner_path(scanner)

255

256 - def set_executor(self, executor):

257 """Set the action executor for this node.""" 258 self.executor = executor

259

260 - def get_executor(self, create=1):

261 """Fetch the action executor for this node. Create one if 262 there isn't already one, and requested to do so.""" 263 try: 264 executor = self.executor 265 except AttributeError: 266 if not create: 267 raise 268 try: 269 act = self.builder.action 270 except AttributeError: 271 executor = SCons.Executor.Null(targets=[self]) 272 else: 273 executor = SCons.Executor.Executor(act, 274 self.env or self.builder.env, 275 [self.builder.overrides], 276 [self], 277 self.sources) 278 self.executor = executor 279 return executor

280

281 - def executor_cleanup(self):

282 """Let the executor clean up any cached information.""" 283 try: 284 executor = self.get_executor(create=None) 285 except AttributeError: 286 pass 287 else: 288 executor.cleanup()

289

290 - def reset_executor(self):

291 "Remove cached executor; forces recompute when needed." 292 try: 293 delattr(self, 'executor') 294 except AttributeError: 295 pass

296

297 - def push_to_cache(self):

298 """Try to push a node into a cache 299 """ 300 pass

301

302 - def retrieve_from_cache(self):

303 """Try to retrieve the node's content from a cache 304 305 This method is called from multiple threads in a parallel build, 306 so only do thread safe stuff here. Do thread unsafe stuff in 307 built(). 308 309 Returns true iff the node was successfully retrieved. 310 """ 311 return 0

312 313 # 314 # Taskmaster interface subsystem 315 # 316

317 - def make_ready(self):

318 """Get a Node ready for evaluation. 319 320 This is called before the Taskmaster decides if the Node is 321 up-to-date or not. Overriding this method allows for a Node 322 subclass to be disambiguated if necessary, or for an implicit 323 source builder to be attached. 324 """ 325 pass

326

327 - def prepare(self):

328 """Prepare for this Node to be built. 329 330 This is called after the Taskmaster has decided that the Node 331 is out-of-date and must be rebuilt, but before actually calling 332 the method to build the Node. 333 334 This default implementation checks that explicit or implicit 335 dependencies either exist or are derived, and initializes the 336 BuildInfo structure that will hold the information about how 337 this node is, uh, built. 338 339 (The existence of source files is checked separately by the 340 Executor, which aggregates checks for all of the targets built 341 by a specific action.) 342 343 Overriding this method allows for for a Node subclass to remove 344 the underlying file from the file system. Note that subclass 345 methods should call this base class method to get the child 346 check and the BuildInfo structure. 347 """ 348 for d in self.depends: 349 if d.missing(): 350 msg = "Explicit dependency `%s' not found, needed by target `%s'." 351 raise SCons.Errors.StopError(msg % (d, self)) 352 if self.implicit is not None: 353 for i in self.implicit: 354 if i.missing(): 355 msg = "Implicit dependency `%s' not found, needed by target `%s'." 356 raise SCons.Errors.StopError(msg % (i, self)) 357 self.binfo = self.get_binfo()

358

359 - def build(self, **kw):

360 """Actually build the node. 361 362 This is called by the Taskmaster after it's decided that the 363 Node is out-of-date and must be rebuilt, and after the prepare() 364 method has gotten everything, uh, prepared. 365 366 This method is called from multiple threads in a parallel build, 367 so only do thread safe stuff here. Do thread unsafe stuff 368 in built(). 369 370 """ 371 try: 372 self.get_executor()(self, **kw) 373 except SCons.Errors.BuildError, e: 374 e.node = self 375 raise

376

377 - def built(self):

378 """Called just after this node is successfully built.""" 379 380 # Clear the implicit dependency caches of any Nodes 381 # waiting for this Node to be built. 382 for parent in self.waiting_parents: 383 parent.implicit = None 384 385 self.clear() 386 387 self.ninfo.update(self)

388

389 - def visited(self):

390 """Called just after this node has been visited (with or 391 without a build).""" 392 try: 393 binfo = self.binfo 394 except AttributeError: 395 # Apparently this node doesn't need build info, so 396 # don't bother calculating or storing it. 397 pass 398 else: 399 self.ninfo.update(self) 400 self.store_info()

401 402 # 403 # 404 # 405

406 - def add_to_waiting_s_e(self, node):

407 self.waiting_s_e.add(node)

408

409 - def add_to_waiting_parents(self, node):

410 """ 411 Returns the number of nodes added to our waiting parents list: 412 1 if we add a unique waiting parent, 0 if not. (Note that the 413 returned values are intended to be used to increment a reference 414 count, so don't think you can "clean up" this function by using 415 True and False instead...) 416 """ 417 wp = self.waiting_parents 418 if node in wp: 419 return 0 420 wp.add(node) 421 return 1

422

423 - def postprocess(self):

424 """Clean up anything we don't need to hang onto after we've 425 been built.""" 426 self.executor_cleanup() 427 self.waiting_parents = set()

428

429 - def clear(self):

430 """Completely clear a Node of all its cached state (so that it 431 can be re-evaluated by interfaces that do continuous integration 432 builds). 433 """ 434 # The del_binfo() call here isn't necessary for normal execution, 435 # but is for interactive mode, where we might rebuild the same 436 # target and need to start from scratch. 437 self.del_binfo() 438 self.clear_memoized_values() 439 self.ninfo = self.new_ninfo() 440 self.executor_cleanup() 441 try: 442 delattr(self, '_calculated_sig') 443 except AttributeError: 444 pass 445 self.includes = None

446

447 - def clear_memoized_values(self):

448 self._memo = {}

449

450 - def builder_set(self, builder):

451 self.builder = builder 452 try: 453 del self.executor 454 except AttributeError: 455 pass

456

457 - def has_builder(self):

458 """Return whether this Node has a builder or not. 459 460 In Boolean tests, this turns out to be a *lot* more efficient 461 than simply examining the builder attribute directly ("if 462 node.builder: ..."). When the builder attribute is examined 463 directly, it ends up calling __getattr__ for both the __len__ 464 and __nonzero__ attributes on instances of our Builder Proxy 465 class(es), generating a bazillion extra calls and slowing 466 things down immensely. 467 """ 468 try: 469 b = self.builder 470 except AttributeError: 471 # There was no explicit builder for this Node, so initialize 472 # the self.builder attribute to None now. 473 b = self.builder = None 474 return b is not None

475

476 - def set_explicit(self, is_explicit):

477 self.is_explicit = is_explicit

478

479 - def has_explicit_builder(self):

480 """Return whether this Node has an explicit builder 481 482 This allows an internal Builder created by SCons to be marked 483 non-explicit, so that it can be overridden by an explicit 484 builder that the user supplies (the canonical example being 485 directories).""" 486 try: 487 return self.is_explicit 488 except AttributeError: 489 self.is_explicit = None 490 return self.is_explicit

491

492 - def get_builder(self, default_builder=None):

493 """Return the set builder, or a specified default value""" 494 try: 495 return self.builder 496 except AttributeError: 497 return default_builder

498 499 multiple_side_effect_has_builder = has_builder 500

501 - def is_derived(self):

502 """ 503 Returns true iff this node is derived (i.e. built). 504 505 This should return true only for nodes whose path should be in 506 the variant directory when duplicate=0 and should contribute their build 507 signatures when they are used as source files to other derived files. For 508 example: source with source builders are not derived in this sense, 509 and hence should not return true. 510 """ 511 return self.has_builder() or self.side_effect

512

513 - def alter_targets(self):

514 """Return a list of alternate targets for this Node. 515 """ 516 return [], None

517

518 - def get_found_includes(self, env, scanner, path):

519 """Return the scanned include lines (implicit dependencies) 520 found in this node. 521 522 The default is no implicit dependencies. We expect this method 523 to be overridden by any subclass that can be scanned for 524 implicit dependencies. 525 """ 526 return []

527

528 - def get_implicit_deps(self, env, scanner, path):

529 """Return a list of implicit dependencies for this node. 530 531 This method exists to handle recursive invocation of the scanner 532 on the implicit dependencies returned by the scanner, if the 533 scanner's recursive flag says that we should. 534 """ 535 if not scanner: 536 return [] 537 538 # Give the scanner a chance to select a more specific scanner 539 # for this Node. 540 #scanner = scanner.select(self) 541 542 nodes = [self] 543 seen = {} 544 seen[self] = 1 545 deps = [] 546 while nodes: 547 n = nodes.pop(0) 548 d = [x for x in n.get_found_includes(env, scanner, path) if x not in seen] 549 if d: 550 deps.extend(d) 551 for n in d: 552 seen[n] = 1 553 nodes.extend(scanner.recurse_nodes(d)) 554 555 return deps

556

557 - def get_env_scanner(self, env, kw={}):

558 return env.get_scanner(self.scanner_key())

559

560 - def get_target_scanner(self):

561 return self.builder.target_scanner

562

563 - def get_source_scanner(self, node):

564 """Fetch the source scanner for the specified node 565 566 NOTE: "self" is the target being built, "node" is 567 the source file for which we want to fetch the scanner. 568 569 Implies self.has_builder() is true; again, expect to only be 570 called from locations where this is already verified. 571 572 This function may be called very often; it attempts to cache 573 the scanner found to improve performance. 574 """ 575 scanner = None 576 try: 577 scanner = self.builder.source_scanner 578 except AttributeError: 579 pass 580 if not scanner: 581 # The builder didn't have an explicit scanner, so go look up 582 # a scanner from env['SCANNERS'] based on the node's scanner 583 # key (usually the file extension). 584 scanner = self.get_env_scanner(self.get_build_env()) 585 if scanner: 586 scanner = scanner.select(node) 587 return scanner

588

589 - def add_to_implicit(self, deps):

590 if not hasattr(self, 'implicit') or self.implicit is None: 591 self.implicit = [] 592 self.implicit_set = set() 593 self._children_reset() 594 self._add_child(self.implicit, self.implicit_set, deps)

595

596 - def scan(self):

597 """Scan this node's dependents for implicit dependencies.""" 598 # Don't bother scanning non-derived files, because we don't 599 # care what their dependencies are. 600 # Don't scan again, if we already have scanned. 601 if self.implicit is not None: 602 return 603 self.implicit = [] 604 self.implicit_set = set() 605 self._children_reset() 606 if not self.has_builder(): 607 return 608 609 build_env = self.get_build_env() 610 executor = self.get_executor() 611 612 # Here's where we implement --implicit-cache. 613 if implicit_cache and not implicit_deps_changed: 614 implicit = self.get_stored_implicit() 615 if implicit is not None: 616 # We now add the implicit dependencies returned from the 617 # stored .sconsign entry to have already been converted 618 # to Nodes for us. (We used to run them through a 619 # source_factory function here.) 620 621 # Update all of the targets with them. This 622 # essentially short-circuits an N*M scan of the 623 # sources for each individual target, which is a hell 624 # of a lot more efficient. 625 for tgt in executor.get_all_targets(): 626 tgt.add_to_implicit(implicit) 627 628 if implicit_deps_unchanged or self.is_up_to_date(): 629 return 630 # one of this node's sources has changed, 631 # so we must recalculate the implicit deps: 632 self.implicit = [] 633 self.implicit_set = set() 634 635 # Have the executor scan the sources. 636 executor.scan_sources(self.builder.source_scanner) 637 638 # If there's a target scanner, have the executor scan the target 639 # node itself and associated targets that might be built. 640 scanner = self.get_target_scanner() 641 if scanner: 642 executor.scan_targets(scanner)

643

644 - def scanner_key(self):

645 return None

646

647 - def select_scanner(self, scanner):

648 """Selects a scanner for this Node. 649 650 This is a separate method so it can be overridden by Node 651 subclasses (specifically, Node.FS.Dir) that *must* use their 652 own Scanner and don't select one the Scanner.Selector that's 653 configured for the target. 654 """ 655 return scanner.select(self)

656

657 - def env_set(self, env, safe=0):

658 if safe and self.env: 659 return 660 self.env = env

661 662 # 663 # SIGNATURE SUBSYSTEM 664 # 665 666 NodeInfo = NodeInfoBase 667 BuildInfo = BuildInfoBase 668

669 - def new_ninfo(self):

670 ninfo = self.NodeInfo(self) 671 return ninfo

672

673 - def get_ninfo(self):

674 try: 675 return self.ninfo 676 except AttributeError: 677 self.ninfo = self.new_ninfo() 678 return self.ninfo

679

680 - def new_binfo(self):

681 binfo = self.BuildInfo(self) 682 return binfo

683

684 - def get_binfo(self):

685 """ 686 Fetch a node's build information. 687 688 node - the node whose sources will be collected 689 cache - alternate node to use for the signature cache 690 returns - the build signature 691 692 This no longer handles the recursive descent of the 693 node's children's signatures. We expect that they're 694 already built and updated by someone else, if that's 695 what's wanted. 696 """ 697 try: 698 return self.binfo 699 except AttributeError: 700 pass 701 702 binfo = self.new_binfo() 703 self.binfo = binfo 704 705 executor = self.get_executor() 706 ignore_set = self.ignore_set 707 708 if self.has_builder(): 709 binfo.bact = str(executor) 710 binfo.bactsig = SCons.Util.MD5signature(executor.get_contents()) 711 712 if self._specific_sources: 713 sources = [] 714 for s in self.sources: 715 if s not in ignore_set: 716 sources.append(s) 717 else: 718 sources = executor.get_unignored_sources(self, self.ignore) 719 seen = set() 720 bsources = [] 721 bsourcesigs = [] 722 for s in sources: 723 if not s in seen: 724 seen.add(s) 725 bsources.append(s) 726 bsourcesigs.append(s.get_ninfo()) 727 binfo.bsources = bsources 728 binfo.bsourcesigs = bsourcesigs 729 730 depends = self.depends 731 dependsigs = [] 732 for d in depends: 733 if d not in ignore_set: 734 dependsigs.append(d.get_ninfo()) 735 binfo.bdepends = depends 736 binfo.bdependsigs = dependsigs 737 738 implicit = self.implicit or [] 739 implicitsigs = [] 740 for i in implicit: 741 if i not in ignore_set: 742 implicitsigs.append(i.get_ninfo()) 743 binfo.bimplicit = implicit 744 binfo.bimplicitsigs = implicitsigs 745 746 return binfo

747

748 - def del_binfo(self):

749 """Delete the build info from this node.""" 750 try: 751 delattr(self, 'binfo') 752 except AttributeError: 753 pass

754

755 - def get_csig(self):

756 try: 757 return self.ninfo.csig 758 except AttributeError: 759 ninfo = self.get_ninfo() 760 ninfo.csig = SCons.Util.MD5signature(self.get_contents()) 761 return self.ninfo.csig

762

763 - def get_cachedir_csig(self):

764 return self.get_csig()

765

766 - def store_info(self):

767 """Make the build signature permanent (that is, store it in the 768 .sconsign file or equivalent).""" 769 pass

770

771 - def do_not_store_info(self):

772 pass

773

774 - def get_stored_info(self):

775 return None

776

777 - def get_stored_implicit(self):

778 """Fetch the stored implicit dependencies""" 779 return None

780 781 # 782 # 783 # 784

785 - def set_precious(self, precious = 1):

786 """Set the Node's precious value.""" 787 self.precious = precious

788

789 - def set_noclean(self, noclean = 1):

790 """Set the Node's noclean value.""" 791 # Make sure noclean is an integer so the --debug=stree 792 # output in Util.py can use it as an index. 793 self.noclean = noclean and 1 or 0

794

795 - def set_nocache(self, nocache = 1):

796 """Set the Node's nocache value.""" 797 # Make sure nocache is an integer so the --debug=stree 798 # output in Util.py can use it as an index. 799 self.nocache = nocache and 1 or 0

800

801 - def set_always_build(self, always_build = 1):

802 """Set the Node's always_build value.""" 803 self.always_build = always_build

804

805 - def exists(self):

806 """Does this node exists?""" 807 # All node exist by default: 808 return 1

809

810 - def rexists(self):

811 """Does this node exist locally or in a repositiory?""" 812 # There are no repositories by default: 813 return self.exists()

814

815 - def missing(self):

816 return not self.is_derived() and \ 817 not self.linked and \ 818 not self.rexists()

819

820 - def remove(self):

821 """Remove this Node: no-op by default.""" 822 return None

823

824 - def add_dependency(self, depend):

825 """Adds dependencies.""" 826 try: 827 self._add_child(self.depends, self.depends_set, depend) 828 except TypeError, e: 829 e = e.args[0] 830 if SCons.Util.is_List(e): 831 s = list(map(str, e)) 832 else: 833 s = str(e) 834 raise SCons.Errors.UserError("attempted to add a non-Node dependency to %s:\n\t%s is a %s, not a Node" % (str(self), s, type(e)))

835

836 - def add_prerequisite(self, prerequisite):

837 """Adds prerequisites""" 838 self.prerequisites.extend(prerequisite) 839 self._children_reset()

840

841 - def add_ignore(self, depend):

842 """Adds dependencies to ignore.""" 843 try: 844 self._add_child(self.ignore, self.ignore_set, depend) 845 except TypeError, e: 846 e = e.args[0] 847 if SCons.Util.is_List(e): 848 s = list(map(str, e)) 849 else: 850 s = str(e) 851 raise SCons.Errors.UserError("attempted to ignore a non-Node dependency of %s:\n\t%s is a %s, not a Node" % (str(self), s, type(e)))

852

853 - def add_source(self, source):

854 """Adds sources.""" 855 if self._specific_sources: 856 return 857 try: 858 self._add_child(self.sources, self.sources_set, source) 859 except TypeError, e: 860 e = e.args[0] 861 if SCons.Util.is_List(e): 862 s = list(map(str, e)) 863 else: 864 s = str(e) 865 raise SCons.Errors.UserError("attempted to add a non-Node as source of %s:\n\t%s is a %s, not a Node" % (str(self), s, type(e)))

866

867 - def _add_child(self, collection, set, child):

868 """Adds 'child' to 'collection', first checking 'set' to see if it's 869 already present.""" 870 #if type(child) is not type([]): 871 # child = [child] 872 #for c in child: 873 # if not isinstance(c, Node): 874 # raise TypeError, c 875 added = None 876 for c in child: 877 if c not in set: 878 set.add(c) 879 collection.append(c) 880 added = 1 881 if added: 882 self._children_reset()

883

884 - def set_specific_source(self, source):

885 self.add_source(source) 886 self._specific_sources = True

887

888 - def add_wkid(self, wkid):

889 """Add a node to the list of kids waiting to be evaluated""" 890 if self.wkids is not None: 891 self.wkids.append(wkid)

892

893 - def _children_reset(self):

894 self.clear_memoized_values() 895 # We need to let the Executor clear out any calculated 896 # build info that it's cached so we can re-calculate it. 897 self.executor_cleanup()

898 899 memoizer_counters.append(SCons.Memoize.CountValue('_children_get')) 900

901 - def _children_get(self):

902 try: 903 return self._memo['children_get'] 904 except KeyError: 905 pass 906 907 # The return list may contain duplicate Nodes, especially in 908 # source trees where there are a lot of repeated #includes 909 # of a tangle of .h files. Profiling shows, however, that 910 # eliminating the duplicates with a brute-force approach that 911 # preserves the order (that is, something like: 912 # 913 # u = [] 914 # for n in list: 915 # if n not in u: 916 # u.append(n)" 917 # 918 # takes more cycles than just letting the underlying methods 919 # hand back cached values if a Node's information is requested 920 # multiple times. (Other methods of removing duplicates, like 921 # using dictionary keys, lose the order, and the only ordered 922 # dictionary patterns I found all ended up using "not in" 923 # internally anyway...) 924 if self.ignore_set: 925 if self.implicit is None: 926 iter = chain(self.sources,self.depends) 927 else: 928 iter = chain(self.sources, self.depends, self.implicit) 929 930 children = [] 931 for i in iter: 932 if i not in self.ignore_set: 933 children.append(i) 934 else: 935 if self.implicit is None: 936 children = self.sources + self.depends 937 else: 938 children = self.sources + self.depends + self.implicit 939 940 self._memo['children_get'] = children 941 return children

942

943 - def all_children(self, scan=1):

944 """Return a list of all the node's direct children.""" 945 if scan: 946 self.scan() 947 948 # The return list may contain duplicate Nodes, especially in 949 # source trees where there are a lot of repeated #includes 950 # of a tangle of .h files. Profiling shows, however, that 951 # eliminating the duplicates with a brute-force approach that 952 # preserves the order (that is, something like: 953 # 954 # u = [] 955 # for n in list: 956 # if n not in u: 957 # u.append(n)" 958 # 959 # takes more cycles than just letting the underlying methods 960 # hand back cached values if a Node's information is requested 961 # multiple times. (Other methods of removing duplicates, like 962 # using dictionary keys, lose the order, and the only ordered 963 # dictionary patterns I found all ended up using "not in" 964 # internally anyway...) 965 if self.implicit is None: 966 return self.sources + self.depends 967 else: 968 return self.sources + self.depends + self.implicit

969

970 - def children(self, scan=1):

971 """Return a list of the node's direct children, minus those 972 that are ignored by this node.""" 973 if scan: 974 self.scan() 975 return self._children_get()

976

977 - def set_state(self, state):

978 self.state = state

979

980 - def get_state(self):

981 return self.state

982

983 - def state_has_changed(self, target, prev_ni):

984 return (self.state != SCons.Node.up_to_date)

985

986 - def get_env(self):

987 env = self.env 988 if not env: 989 import SCons.Defaults 990 env = SCons.Defaults.DefaultEnvironment() 991 return env

992

993 - def changed_since_last_build(self, target, prev_ni):

994 """ 995 996 Must be overridden in a specific subclass to return True if this 997 Node (a dependency) has changed since the last time it was used 998 to build the specified target. prev_ni is this Node's state (for 999 example, its file timestamp, length, maybe content signature) 1000 as of the last time the target was built. 1001 1002 Note that this method is called through the dependency, not the 1003 target, because a dependency Node must be able to use its own 1004 logic to decide if it changed. For example, File Nodes need to 1005 obey if we're configured to use timestamps, but Python Value Nodes 1006 never use timestamps and always use the content. If this method 1007 were called through the target, then each Node's implementation 1008 of this method would have to have more complicated logic to 1009 handle all the different Node types on which it might depend. 1010 """ 1011 raise NotImplementedError

1012

1013 - def Decider(self, function):

1014 SCons.Util.AddMethod(self, function, 'changed_since_last_build')

1015

1016 - def changed(self, node=None):

1017 """ 1018 Returns if the node is up-to-date with respect to the BuildInfo 1019 stored last time it was built. The default behavior is to compare 1020 it against our own previously stored BuildInfo, but the stored 1021 BuildInfo from another Node (typically one in a Repository) 1022 can be used instead. 1023 1024 Note that we now *always* check every dependency. We used to 1025 short-circuit the check by returning as soon as we detected 1026 any difference, but we now rely on checking every dependency 1027 to make sure that any necessary Node information (for example, 1028 the content signature of an #included .h file) is updated. 1029 """ 1030 t = 0 1031 if t: Trace('changed(%s [%s], %s)' % (self, classname(self), node)) 1032 if node is None: 1033 node = self 1034 1035 result = False 1036 1037 bi = node.get_stored_info().binfo 1038 then = bi.bsourcesigs + bi.bdependsigs + bi.bimplicitsigs 1039 children = self.children() 1040 1041 diff = len(children) - len(then) 1042 if diff: 1043 # The old and new dependency lists are different lengths. 1044 # This always indicates that the Node must be rebuilt. 1045 # We also extend the old dependency list with enough None 1046 # entries to equal the new dependency list, for the benefit 1047 # of the loop below that updates node information. 1048 then.extend([None] * diff) 1049 if t: Trace(': old %s new %s' % (len(then), len(children))) 1050 result = True 1051 1052 for child, prev_ni in zip(children, then): 1053 if child.changed_since_last_build(self, prev_ni): 1054 if t: Trace(': %s changed' % child) 1055 result = True 1056 1057 contents = self.get_executor().get_contents() 1058 if self.has_builder(): 1059 import SCons.Util 1060 newsig = SCons.Util.MD5signature(contents) 1061 if bi.bactsig != newsig: 1062 if t: Trace(': bactsig %s != newsig %s' % (bi.bactsig, newsig)) 1063 result = True 1064 1065 if not result: 1066 if t: Trace(': up to date') 1067 1068 if t: Trace('\n') 1069 1070 return result

1071

1072 - def is_up_to_date(self):

1073 """Default check for whether the Node is current: unknown Node 1074 subtypes are always out of date, so they will always get built.""" 1075 return None

1076

1077 - def children_are_up_to_date(self):

1078 """Alternate check for whether the Node is current: If all of 1079 our children were up-to-date, then this Node was up-to-date, too. 1080 1081 The SCons.Node.Alias and SCons.Node.Python.Value subclasses 1082 rebind their current() method to this method.""" 1083 # Allow the children to calculate their signatures. 1084 self.binfo = self.get_binfo() 1085 if self.always_build: 1086 return None 1087 state = 0 1088 for kid in self.children(None): 1089 s = kid.get_state() 1090 if s and (not state or s > state): 1091 state = s 1092 return (state == 0 or state == SCons.Node.up_to_date)

1093

1094 - def is_literal(self):

1095 """Always pass the string representation of a Node to 1096 the command interpreter literally.""" 1097 return 1

1098

1099 - def render_include_tree(self):

1100 """ 1101 Return a text representation, suitable for displaying to the 1102 user, of the include tree for the sources of this node. 1103 """ 1104 if self.is_derived() and self.env: 1105 env = self.get_build_env() 1106 for s in self.sources: 1107 scanner = self.get_source_scanner(s) 1108 if scanner: 1109 path = self.get_build_scanner_path(scanner) 1110 else: 1111 path = None 1112 def f(node, env=env, scanner=scanner, path=path): 1113 return node.get_found_includes(env, scanner, path)

1114 return SCons.Util.render_tree(s, f, 1) 1115 else: 1116 return None

Source Code for Package SCons.Node