3 The Node package for the SCons software construction utility.
5 This is, in many ways, the heart of SCons.
7 A Node is where we encapsulate all of the dependency information about
8 any thing that SCons can build, or about any thing which SCons can use
9 to build some other thing. The canonical "thing," of course, is a file,
10 but a Node can also represent something remote (like a web page) or
11 something completely abstract (like an Alias).
13 Each specific type of "thing" is specifically represented by a subclass
14 of the Node base class: Node.FS.File for files, Node.Alias for aliases,
15 etc. Dependency information is kept here in the base class, and
16 information specific to files/aliases/etc. is in the subclass. The
17 goal, if we've done this correctly, is that any type of "thing" should
18 be able to depend on any other type of "thing."
25 # Permission is hereby granted, free of charge, to any person obtaining
26 # a copy of this software and associated documentation files (the
27 # "Software"), to deal in the Software without restriction, including
28 # without limitation the rights to use, copy, modify, merge, publish,
29 # distribute, sublicense, and/or sell copies of the Software, and to
30 # permit persons to whom the Software is furnished to do so, subject to
31 # the following conditions:
33 # The above copyright notice and this permission notice shall be included
34 # in all copies or substantial portions of the Software.
36 # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY
37 # KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
38 # WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
39 # NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
40 # LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
41 # OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
42 # WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
45 __revision__ = "__FILE__ __REVISION__ __DATE__ __DEVELOPER__"
53 from SCons.Debug import logInstanceCreation
60 # These are in "priority" order, so that the maximum value for any
61 # child/dependency of a node represents the state of that node if
62 # it has no builder of its own. The canonical example is a file
63 # system directory, which is only up to date if all of its children
71 stack = 6 # nodes that are in the current Taskmaster execution stack
83 # controls whether implicit dependencies are cached:
86 # controls whether implicit dep changes are ignored:
87 implicit_deps_unchanged = 0
89 # controls whether the cached implicit deps are ignored:
90 implicit_deps_changed = 0
92 # A variable that can be set to an interface-specific function be called
93 # to annotate a Node with information about its creation.
94 def do_nothing(node): pass
99 def __cmp__(self, other):
100 return cmp(self.__dict__, other.__dict__)
103 """The base Node class, for entities that we know how to
104 build, or use to build other Nodes.
107 __metaclass__ = SCons.Memoize.Memoized_Metaclass
113 if __debug__: logInstanceCreation(self, 'Node.Node')
114 # Note that we no longer explicitly initialize a self.builder
115 # attribute to None here. That's because the self.builder
116 # attribute may be created on-the-fly later by a subclass (the
117 # canonical example being a builder to fetch a file from a
118 # source code system like CVS or Subversion).
120 # Each list of children that we maintain is accompanied by a
121 # dictionary used to look up quickly whether a node is already
122 # present in the list. Empirical tests showed that it was
123 # fastest to maintain them as side-by-side Node attributes in
124 # this way, instead of wrapping up each list+dictionary pair in
125 # a class. (Of course, we could always still do that in the
126 # future if we had a good reason to...).
127 self.sources = [] # source files used to build node
128 self.sources_dict = {}
129 self.depends = [] # explicit dependencies (from Depends)
130 self.depends_dict = {}
131 self.ignore = [] # dependencies to ignore
132 self.ignore_dict = {}
133 self.implicit = None # implicit (scanned) dependencies (None means not scanned yet)
134 self.waiting_parents = []
135 self.wkids = None # Kids yet to walk, when it's an array
138 self.state = no_state
140 self.always_build = None
141 self.found_includes = {}
143 self.attributes = self.Attrs() # Generic place to stick information about the Node.
144 self.side_effect = 0 # true iff this node is a side effect
145 self.side_effects = [] # the side effects of building this target
146 self.pre_actions = []
147 self.post_actions = []
148 self.linked = 0 # is this node linked to the build directory?
150 # Let the interface in which the build engine is embedded
151 # annotate this Node with its own info (like a description of
152 # what line in what file created the node, for example).
155 def get_suffix(self):
158 def get_build_env(self):
159 """Fetch the appropriate Environment to build this node.
161 return self.get_executor().get_build_env()
163 def get_build_scanner_path(self, scanner):
164 """Fetch the appropriate scanner path for this node."""
165 return self.get_executor().get_build_scanner_path(scanner)
167 def set_executor(self, executor):
168 """Set the action executor for this node."""
169 self.executor = executor
171 def get_executor(self, create=1):
172 """Fetch the action executor for this node. Create one if
173 there isn't already one, and requested to do so."""
175 executor = self.executor
176 except AttributeError:
180 act = self.builder.action
181 except AttributeError:
182 executor = SCons.Executor.Null()
185 act = self.pre_actions + act
186 if self.post_actions:
187 act = act + self.post_actions
188 executor = SCons.Executor.Executor(act,
189 self.env or self.builder.env,
190 [self.builder.overrides],
193 self.executor = executor
196 def executor_cleanup(self):
197 """Let the executor clean up any cached information."""
199 executor = self.get_executor(create=None)
200 except AttributeError:
205 def reset_executor(self):
206 "Remove cached executor; forces recompute when needed."
208 delattr(self, 'executor')
209 except AttributeError:
212 def retrieve_from_cache(self):
213 """Try to retrieve the node's content from a cache
215 This method is called from multiple threads in a parallel build,
216 so only do thread safe stuff here. Do thread unsafe stuff in
219 Returns true iff the node was successfully retrieved.
223 def build(self, **kw):
224 """Actually build the node.
226 This method is called from multiple threads in a parallel build,
227 so only do thread safe stuff here. Do thread unsafe stuff in
230 def errfunc(stat, node=self):
231 raise SCons.Errors.BuildError(node=node, errstr="Error %d" % stat)
232 executor = self.get_executor()
233 apply(executor, (self, errfunc), kw)
236 """Called just after this node is successfully built."""
238 # Clear the implicit dependency caches of any Nodes
239 # waiting for this Node to be built.
240 for parent in self.waiting_parents:
241 parent.implicit = None
245 new_binfo = self.binfo
246 except AttributeError:
247 # Node arrived here without build info; apparently it
248 # doesn't need it, so don't bother calculating or storing
252 # Reset this Node's cached state since it was just built and
253 # various state has changed.
256 # Had build info, so it should be stored in the signature
257 # cache. However, if the build info included a content
258 # signature then it should be recalculated before being
262 if hasattr(new_binfo, 'csig'):
263 new_binfo = self.gen_binfo() # sets self.binfo
265 self.binfo = new_binfo
266 self.store_info(new_binfo)
268 def add_to_waiting_parents(self, node):
269 self.waiting_parents.append(node)
271 def call_for_all_waiting_parents(self, func):
273 for parent in self.waiting_parents:
274 parent.call_for_all_waiting_parents(func)
276 def postprocess(self):
277 """Clean up anything we don't need to hang onto after we've
279 self.executor_cleanup()
282 """Completely clear a Node of all its cached state (so that it
283 can be re-evaluated by interfaces that do continuous integration
287 self.executor_cleanup()
291 delattr(self, '_calculated_sig')
292 except AttributeError:
295 self.found_includes = {}
298 self.waiting_parents = []
301 """Called just after this node has been visited
302 without requiring a build.."""
305 def builder_set(self, builder):
307 self.builder = builder
309 def has_builder(self):
310 """Return whether this Node has a builder or not.
312 In Boolean tests, this turns out to be a *lot* more efficient
313 than simply examining the builder attribute directly ("if
314 node.builder: ..."). When the builder attribute is examined
315 directly, it ends up calling __getattr__ for both the __len__
316 and __nonzero__ attributes on instances of our Builder Proxy
317 class(es), generating a bazillion extra calls and slowing
318 things down immensely.
322 except AttributeError:
323 # There was no explicit builder for this Node, so initialize
324 # the self.builder attribute to None now.
329 def set_explicit(self, is_explicit):
330 self.is_explicit = is_explicit
332 def has_explicit_builder(self):
333 """Return whether this Node has an explicit builder
335 This allows an internal Builder created by SCons to be marked
336 non-explicit, so that it can be overridden by an explicit
337 builder that the user supplies (the canonical example being
340 return self.is_explicit
341 except AttributeError:
342 self.is_explicit = None
343 return self.is_explicit
345 def get_builder(self, default_builder=None):
346 """Return the set builder, or a specified default value"""
349 except AttributeError:
350 return default_builder
352 multiple_side_effect_has_builder = has_builder
354 def is_derived(self):
356 Returns true iff this node is derived (i.e. built).
358 This should return true only for nodes whose path should be in
359 the build directory when duplicate=0 and should contribute their build
360 signatures when they are used as source files to other derived files. For
361 example: source with source builders are not derived in this sense,
362 and hence should not return true.
365 return self.has_builder() or self.side_effect
367 def is_pseudo_derived(self):
369 Returns true iff this node is built, but should use a source path
370 when duplicate=0 and should contribute a content signature (i.e.
371 source signature) when used as a source for other derived files.
375 def alter_targets(self):
376 """Return a list of alternate targets for this Node.
380 def get_found_includes(self, env, scanner, path):
381 """Return the scanned include lines (implicit dependencies)
384 The default is no implicit dependencies. We expect this method
385 to be overridden by any subclass that can be scanned for
386 implicit dependencies.
390 def get_implicit_deps(self, env, scanner, path):
391 """Return a list of implicit dependencies for this node.
393 This method exists to handle recursive invocation of the scanner
394 on the implicit dependencies returned by the scanner, if the
395 scanner's recursive flag says that we should.
400 # Give the scanner a chance to select a more specific scanner
402 scanner = scanner.select(self)
410 d = filter(lambda x, seen=seen: not seen.has_key(x),
411 n.get_found_includes(env, scanner, path))
416 nodes.extend(scanner.recurse_nodes(d))
420 def implicit_factory(self, path):
422 Turn a cache implicit dependency path into a node.
423 This is called so many times that doing caching
424 here is a significant performance boost.
427 return self.builder.source_factory(path)
429 def get_scanner(self, env, kw={}):
430 return env.get_scanner(self.scanner_key())
432 def get_source_scanner(self, node):
433 """Fetch the source scanner for the specified node
435 NOTE: "self" is the target being built, "node" is
436 the source file for which we want to fetch the scanner.
438 Implies self.has_builder() is true; again, expect to only be
439 called from locations where this is already verified.
441 This function may be called very often; it attempts to cache
442 the scanner found to improve performance.
446 scanner = self.builder.source_scanner
447 except AttributeError:
450 # The builder didn't have an explicit scanner, so go look up
451 # a scanner from env['SCANNERS'] based on the node's scanner
452 # key (usually the file extension).
453 scanner = self.get_scanner(self.get_build_env())
455 scanner = scanner.select(node)
458 def add_to_implicit(self, deps):
459 if not hasattr(self, 'implicit') or self.implicit is None:
461 self.implicit_dict = {}
462 self._children_reset()
463 self._add_child(self.implicit, self.implicit_dict, deps)
466 """Scan this node's dependents for implicit dependencies."""
467 # Don't bother scanning non-derived files, because we don't
468 # care what their dependencies are.
469 # Don't scan again, if we already have scanned.
470 if not self.implicit is None:
473 self.implicit_dict = {}
474 self._children_reset()
475 if not self.has_builder():
478 build_env = self.get_build_env()
480 # Here's where we implement --implicit-cache.
481 if implicit_cache and not implicit_deps_changed:
482 implicit = self.get_stored_implicit()
483 if implicit is not None:
484 implicit = map(self.implicit_factory, implicit)
485 self._add_child(self.implicit, self.implicit_dict, implicit)
486 calc = build_env.get_calculator()
487 if implicit_deps_unchanged or self.current(calc):
490 # one of this node's sources has changed, so
491 # we need to recalculate the implicit deps,
494 self.implicit_dict = {}
495 self._children_reset()
498 executor = self.get_executor()
500 # Have the executor scan the sources.
501 executor.scan_sources(self.builder.source_scanner)
503 # If there's a target scanner, have the executor scan the target
504 # node itself and associated targets that might be built.
505 scanner = self.builder.target_scanner
507 executor.scan_targets(scanner)
509 def scanner_key(self):
512 def env_set(self, env, safe=0):
513 if safe and self.env:
517 def calculator(self):
518 import SCons.Defaults
520 env = self.env or SCons.Defaults.DefaultEnvironment()
521 return env.get_calculator()
523 def calc_signature(self, calc=None):
525 Select and calculate the appropriate build signature for a node.
529 calc - the signature calculation module
530 returns - the signature
532 if self.is_derived():
533 import SCons.Defaults
535 env = self.env or SCons.Defaults.DefaultEnvironment()
536 if env.use_build_signature():
537 return self.calc_bsig(calc)
538 elif not self.rexists():
540 return self.calc_csig(calc)
546 """Delete the bsig from this node."""
548 delattr(self, 'binfo')
549 except AttributeError:
552 def calc_bsig(self, calc=None):
554 return self.binfo.bsig
555 except AttributeError:
556 self.binfo = self.gen_binfo(calc)
557 return self.binfo.bsig
559 def gen_binfo(self, calc=None, scan=1):
561 Generate a node's build signature, the digested signatures
562 of its dependency files and build information.
564 node - the node whose sources will be collected
565 cache - alternate node to use for the signature cache
566 returns - the build signature
568 This no longer handles the recursive descent of the
569 node's children's signatures. We expect that they're
570 already built and updated by someone else, if that's
576 calc = self.calculator()
578 binfo = self.new_binfo()
583 executor = self.get_executor()
585 sourcelist, sourcesigs, bsources = executor.get_source_binfo(calc, self.ignore)
586 depends = self.depends
587 implicit = self.implicit or []
590 depends = filter(self.do_not_ignore, depends)
591 implicit = filter(self.do_not_ignore, implicit)
593 def calc_signature(node, calc=calc):
594 return node.calc_signature(calc)
595 dependsigs = map(calc_signature, depends)
596 implicitsigs = map(calc_signature, implicit)
598 sigs = sourcesigs + dependsigs + implicitsigs
600 if self.has_builder():
601 binfo.bact = str(executor)
602 binfo.bactsig = calc.module.signature(executor)
603 sigs.append(binfo.bactsig)
605 binfo.bsources = bsources
606 binfo.bdepends = map(str, depends)
607 binfo.bimplicit = map(str, implicit)
609 binfo.bsourcesigs = sourcesigs
610 binfo.bdependsigs = dependsigs
611 binfo.bimplicitsigs = implicitsigs
613 binfo.bsig = calc.module.collect(filter(None, sigs))
620 except AttributeError:
623 def calc_csig(self, calc=None):
626 except AttributeError:
627 binfo = self.binfo = self.new_binfo()
630 except AttributeError:
632 calc = self.calculator()
633 binfo.csig = calc.module.signature(self)
634 self.store_info(binfo)
637 def store_info(self, obj):
638 """Make the build signature permanent (that is, store it in the
639 .sconsign file or equivalent)."""
642 def get_stored_info(self):
645 def get_stored_implicit(self):
646 """Fetch the stored implicit dependencies"""
649 def set_precious(self, precious = 1):
650 """Set the Node's precious value."""
651 self.precious = precious
653 def set_always_build(self, always_build = 1):
654 """Set the Node's always_build value."""
655 self.always_build = always_build
658 """Does this node exists?"""
659 # All node exist by default:
663 """Does this node exist locally or in a repositiory?"""
664 # There are no repositories by default:
669 return not self.is_derived() and \
670 not self.is_pseudo_derived() and \
671 not self.linked and \
675 """Prepare for this Node to be created.
676 The default implemenation checks that all children either exist
680 if not self.implicit is None:
681 l = l + self.implicit
682 missing_sources = self.get_executor().get_missing_sources() \
683 + filter(lambda c: c.missing(), l)
685 desc = "Source `%s' not found, needed by target `%s'." % (missing_sources[0], self)
686 raise SCons.Errors.StopError, desc
689 """Remove this Node: no-op by default."""
692 def add_dependency(self, depend):
693 """Adds dependencies."""
695 self._add_child(self.depends, self.depends_dict, depend)
698 if SCons.Util.is_List(e):
702 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)))
704 def add_ignore(self, depend):
705 """Adds dependencies to ignore."""
707 self._add_child(self.ignore, self.ignore_dict, depend)
710 if SCons.Util.is_List(e):
714 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)))
716 def add_source(self, source):
719 self._add_child(self.sources, self.sources_dict, source)
722 if SCons.Util.is_List(e):
726 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)))
728 def _add_child(self, collection, dict, child):
729 """Adds 'child' to 'collection', first checking 'dict' to see
730 if it's already present."""
731 if type(child) is not type([]):
734 if not isinstance(c, Node):
738 if not dict.has_key(c):
743 self._children_reset()
745 def add_wkid(self, wkid):
746 """Add a node to the list of kids waiting to be evaluated"""
747 if self.wkids != None:
748 self.wkids.append(wkid)
750 def _children_reset(self):
752 # We need to let the Executor clear out any calculated
753 # bsig info that it's cached so we can re-calculate it.
754 self.executor_cleanup()
756 def do_not_ignore(self, node):
757 return node not in self.ignore
759 def _all_children_get(self):
760 # The return list may contain duplicate Nodes, especially in
761 # source trees where there are a lot of repeated #includes
762 # of a tangle of .h files. Profiling shows, however, that
763 # eliminating the duplicates with a brute-force approach that
764 # preserves the order (that is, something like:
771 # takes more cycles than just letting the underlying methods
772 # hand back cached values if a Node's information is requested
773 # multiple times. (Other methods of removing duplicates, like
774 # using dictionary keys, lose the order, and the only ordered
775 # dictionary patterns I found all ended up using "not in"
776 # internally anyway...)
777 if self.implicit is None:
778 return self.sources + self.depends
780 return self.sources + self.depends + self.implicit
782 def _children_get(self):
784 children = self._all_children_get()
786 children = filter(self.do_not_ignore, children)
789 def all_children(self, scan=1):
790 """Return a list of all the node's direct children."""
793 return self._all_children_get()
795 def children(self, scan=1):
796 """Return a list of the node's direct children, minus those
797 that are ignored by this node."""
800 return self._children_get()
802 def set_state(self, state):
808 def current(self, calc=None):
809 """Default check for whether the Node is current: unknown Node
810 subtypes are always out of date, so they will always get built."""
813 def children_are_up_to_date(self, calc=None):
814 """Alternate check for whether the Node is current: If all of
815 our children were up-to-date, then this Node was up-to-date, too.
817 The SCons.Node.Alias and SCons.Node.Python.Value subclasses
818 rebind their current() method to this method."""
819 # Allow the children to calculate their signatures.
820 self.binfo = self.gen_binfo(calc)
821 if self.always_build:
824 for kid in self.children(None):
826 if s and (not state or s > state):
828 return (state == 0 or state == SCons.Node.up_to_date)
830 def is_literal(self):
831 """Always pass the string representation of a Node to
832 the command interpreter literally."""
835 def add_pre_action(self, act):
836 """Adds an Action performed on this Node only before
838 self.pre_actions.append(act)
839 # executor must be recomputed to include new pre-actions
840 self.reset_executor()
842 def add_post_action(self, act):
843 """Adds and Action performed on this Node only after
845 self.post_actions.append(act)
846 # executor must be recomputed to include new pre-actions
847 self.reset_executor()
849 def render_include_tree(self):
851 Return a text representation, suitable for displaying to the
852 user, of the include tree for the sources of this node.
854 if self.is_derived() and self.env:
855 env = self.get_build_env()
856 for s in self.sources:
857 scanner = self.get_source_scanner(s)
858 path = self.get_build_scanner_path(scanner)
859 def f(node, env=env, scanner=scanner, path=path):
860 return node.get_found_includes(env, scanner, path)
861 return SCons.Util.render_tree(s, f, 1)
865 def get_abspath(self):
867 Return an absolute path to the Node. This will return simply
868 str(Node) by default, but for Node types that have a concept of
869 relative path, this might return something different.
873 def for_signature(self):
875 Return a string representation of the Node that will always
876 be the same for this particular Node, no matter what. This
877 is by contrast to the __str__() method, which might, for
878 instance, return a relative path for a file Node. The purpose
879 of this method is to generate a value to be used in signature
880 calculation for the command line used to build a target, and
881 we use this method instead of str() to avoid unnecessary
882 rebuilds. This method does not need to return something that
883 would actually work in a command line; it can return any kind of
884 nonsense, so long as it does not change.
888 def get_string(self, for_signature):
889 """This is a convenience function designed primarily to be
890 used in command generators (i.e., CommandGeneratorActions or
891 Environment variables that are callable), which are called
892 with a for_signature argument that is nonzero if the command
893 generator is being called to generate a signature for the
894 command line, which determines if we should rebuild or not.
896 Such command generators should use this method in preference
897 to str(Node) when converting a Node to a string, passing
898 in the for_signature parameter, such that we will call
899 Node.for_signature() or str(Node) properly, depending on whether
900 we are calculating a signature or actually constructing a
903 return self.for_signature()
906 def get_subst_proxy(self):
908 This method is expected to return an object that will function
909 exactly like this Node, except that it implements any additional
910 special features that we would like to be in effect for
911 Environment variable substitution. The principle use is that
912 some Nodes would like to implement a __getattr__() method,
913 but putting that in the Node type itself has a tendency to kill
914 performance. We instead put it in a proxy and return it from
915 this method. It is legal for this method to return self
916 if no new functionality is needed for Environment substitution.
921 if not self.exists():
922 return "building `%s' because it doesn't exist\n" % self
924 old = self.get_stored_info()
928 def dictify(result, kids, sigs):
929 for k, s in zip(kids, sigs):
933 old_bkids = old.bsources + old.bdepends + old.bimplicit
934 except AttributeError:
935 return "Cannot explain why `%s' is being rebuilt: No previous build information found\n" % self
938 dictify(osig, old.bsources, old.bsourcesigs)
939 dictify(osig, old.bdepends, old.bdependsigs)
940 dictify(osig, old.bimplicit, old.bimplicitsigs)
942 new_bsources = map(str, self.binfo.bsources)
943 new_bdepends = map(str, self.binfo.bdepends)
944 new_bimplicit = map(str, self.binfo.bimplicit)
947 dictify(nsig, new_bsources, self.binfo.bsourcesigs)
948 dictify(nsig, new_bdepends, self.binfo.bdependsigs)
949 dictify(nsig, new_bimplicit, self.binfo.bimplicitsigs)
951 new_bkids = new_bsources + new_bdepends + new_bimplicit
952 lines = map(lambda x: "`%s' is no longer a dependency\n" % x,
953 filter(lambda x, nk=new_bkids: not x in nk, old_bkids))
956 if not k in old_bkids:
957 lines.append("`%s' is a new dependency\n" % k)
958 elif osig[k] != nsig[k]:
959 lines.append("`%s' changed\n" % k)
961 if len(lines) == 0 and old_bkids != new_bkids:
962 lines.append("the dependency order changed:\n" +
963 "%sold: %s\n" % (' '*15, old_bkids) +
964 "%snew: %s\n" % (' '*15, new_bkids))
967 newact, newactsig = self.binfo.bact, self.binfo.bactsig
968 def fmt_with_title(title, strlines):
969 lines = string.split(strlines, '\n')
970 sep = '\n' + ' '*(15 + len(title))
971 return ' '*15 + title + string.join(lines, sep) + '\n'
972 if old.bactsig != newactsig:
973 if old.bact == newact:
974 lines.append("the contents of the build action changed\n" +
975 fmt_with_title('action: ', newact))
977 lines.append("the build action changed:\n" +
978 fmt_with_title('old: ', old.bact) +
979 fmt_with_title('new: ', newact))
982 return "rebuilding `%s' for unknown reasons\n" % self
984 preamble = "rebuilding `%s' because" % self
986 return "%s %s" % (preamble, lines[0])
988 lines = ["%s:\n" % preamble] + lines
989 return string.join(lines, ' '*11)
992 ul = UserList.UserList([2])
999 class NodeList(UserList.UserList):
1001 return str(map(str, self.data))
1005 if not SCons.Memoize.has_metaclass:
1007 class Node(SCons.Memoize.Memoizer, _Base):
1008 def __init__(self, *args, **kw):
1009 apply(_Base.__init__, (self,)+args, kw)
1010 SCons.Memoize.Memoizer.__init__(self)
1013 def get_children(node, parent): return node.children()
1014 def ignore_cycle(node, stack): pass
1015 def do_nothing(node, parent): pass
1018 """An iterator for walking a Node tree.
1020 This is depth-first, children are visited before the parent.
1021 The Walker object can be initialized with any node, and
1022 returns the next node on the descent with each next() call.
1023 'kids_func' is an optional function that will be called to
1024 get the children of a node instead of calling 'children'.
1025 'cycle_func' is an optional function that will be called
1026 when a cycle is detected.
1028 This class does not get caught in node cycles caused, for example,
1029 by C header file include loops.
1031 def __init__(self, node, kids_func=get_children,
1032 cycle_func=ignore_cycle,
1033 eval_func=do_nothing):
1034 self.kids_func = kids_func
1035 self.cycle_func = cycle_func
1036 self.eval_func = eval_func
1037 node.wkids = copy.copy(kids_func(node, None))
1039 self.history = {} # used to efficiently detect and avoid cycles
1040 self.history[node] = None
1043 """Return the next node for this walk of the tree.
1045 This function is intentionally iterative, not recursive,
1046 to sidestep any issues of stack size limitations.
1050 if self.stack[-1].wkids:
1051 node = self.stack[-1].wkids.pop(0)
1052 if not self.stack[-1].wkids:
1053 self.stack[-1].wkids = None
1054 if self.history.has_key(node):
1055 self.cycle_func(node, self.stack)
1057 node.wkids = copy.copy(self.kids_func(node, self.stack[-1]))
1058 self.stack.append(node)
1059 self.history[node] = None
1061 node = self.stack.pop()
1062 del self.history[node]
1065 parent = self.stack[-1]
1068 self.eval_func(node, parent)
1073 return not self.stack
1076 arg2nodes_lookups = []