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."
23 # Copyright (c) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008 The SCons Foundation
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__ = "src/engine/SCons/Node/__init__.py 3842 2008/12/20 22:59:52 scons"
48 from itertools import chain, izip
52 from SCons.Debug import logInstanceCreation
57 from SCons.Debug import Trace
60 return string.split(str(obj.__class__), '.')[-1]
64 # These are in "priority" order, so that the maximum value for any
65 # child/dependency of a node represents the state of that node if
66 # it has no builder of its own. The canonical example is a file
67 # system directory, which is only up to date if all of its children
85 # controls whether implicit dependencies are cached:
88 # controls whether implicit dep changes are ignored:
89 implicit_deps_unchanged = 0
91 # controls whether the cached implicit deps are ignored:
92 implicit_deps_changed = 0
94 # A variable that can be set to an interface-specific function be called
95 # to annotate a Node with information about its creation.
96 def do_nothing(node): pass
100 # Classes for signature info for Nodes.
104 The generic base class for signature information for a Node.
106 Node subclasses should subclass NodeInfoBase to provide their own
107 logic for dealing with their own Node-specific signature information.
109 current_version_id = 1
110 def __init__(self, node):
111 # Create an object attribute from the class attribute so it ends up
112 # in the pickled data in the .sconsign file.
113 self._version_id = self.current_version_id
114 def update(self, node):
116 field_list = self.field_list
117 except AttributeError:
122 except AttributeError:
125 func = getattr(node, 'get_' + f)
126 except AttributeError:
129 setattr(self, f, func())
130 def convert(self, node, val):
132 def merge(self, other):
133 self.__dict__.update(other.__dict__)
134 def format(self, field_list=None, names=0):
135 if field_list is None:
137 field_list = self.field_list
138 except AttributeError:
139 field_list = self.__dict__.keys()
142 for field in field_list:
144 f = getattr(self, field)
145 except AttributeError:
155 The generic base class for build information for a Node.
157 This is what gets stored in a .sconsign file for each target file.
158 It contains a NodeInfo instance for this node (signature information
159 that's specific to the type of Node) and direct attributes for the
160 generic build stuff we have to track: sources, explicit dependencies,
161 implicit dependencies, and action information.
163 current_version_id = 1
164 def __init__(self, node):
165 # Create an object attribute from the class attribute so it ends up
166 # in the pickled data in the .sconsign file.
167 self._version_id = self.current_version_id
168 self.bsourcesigs = []
169 self.bdependsigs = []
170 self.bimplicitsigs = []
172 def merge(self, other):
173 self.__dict__.update(other.__dict__)
176 """The base Node class, for entities that we know how to
177 build, or use to build other Nodes.
180 if SCons.Memoize.use_memoizer:
181 __metaclass__ = SCons.Memoize.Memoized_Metaclass
183 memoizer_counters = []
189 if __debug__: logInstanceCreation(self, 'Node.Node')
190 # Note that we no longer explicitly initialize a self.builder
191 # attribute to None here. That's because the self.builder
192 # attribute may be created on-the-fly later by a subclass (the
193 # canonical example being a builder to fetch a file from a
194 # source code system like CVS or Subversion).
196 # Each list of children that we maintain is accompanied by a
197 # dictionary used to look up quickly whether a node is already
198 # present in the list. Empirical tests showed that it was
199 # fastest to maintain them as side-by-side Node attributes in
200 # this way, instead of wrapping up each list+dictionary pair in
201 # a class. (Of course, we could always still do that in the
202 # future if we had a good reason to...).
203 self.sources = [] # source files used to build node
204 self.sources_set = set()
205 self._specific_sources = False
206 self.depends = [] # explicit dependencies (from Depends)
207 self.depends_set = set()
208 self.ignore = [] # dependencies to ignore
209 self.ignore_set = set()
210 self.prerequisites = SCons.Util.UniqueList()
211 self.implicit = None # implicit (scanned) dependencies (None means not scanned yet)
212 self.waiting_parents = set()
213 self.waiting_s_e = set()
215 self.wkids = None # Kids yet to walk, when it's an array
218 self.state = no_state
222 self.always_build = None
224 self.attributes = self.Attrs() # Generic place to stick information about the Node.
225 self.side_effect = 0 # true iff this node is a side effect
226 self.side_effects = [] # the side effects of building this target
227 self.linked = 0 # is this node linked to the variant directory?
229 self.clear_memoized_values()
231 # Let the interface in which the build engine is embedded
232 # annotate this Node with its own info (like a description of
233 # what line in what file created the node, for example).
236 def disambiguate(self, must_exist=None):
239 def get_suffix(self):
242 memoizer_counters.append(SCons.Memoize.CountValue('get_build_env'))
244 def get_build_env(self):
245 """Fetch the appropriate Environment to build this node.
248 return self._memo['get_build_env']
251 result = self.get_executor().get_build_env()
252 self._memo['get_build_env'] = result
255 def get_build_scanner_path(self, scanner):
256 """Fetch the appropriate scanner path for this node."""
257 return self.get_executor().get_build_scanner_path(scanner)
259 def set_executor(self, executor):
260 """Set the action executor for this node."""
261 self.executor = executor
263 def get_executor(self, create=1):
264 """Fetch the action executor for this node. Create one if
265 there isn't already one, and requested to do so."""
267 executor = self.executor
268 except AttributeError:
272 act = self.builder.action
273 except AttributeError:
274 executor = SCons.Executor.Null(targets=[self])
276 executor = SCons.Executor.Executor(act,
277 self.env or self.builder.env,
278 [self.builder.overrides],
281 self.executor = executor
284 def executor_cleanup(self):
285 """Let the executor clean up any cached information."""
287 executor = self.get_executor(create=None)
288 except AttributeError:
293 def reset_executor(self):
294 "Remove cached executor; forces recompute when needed."
296 delattr(self, 'executor')
297 except AttributeError:
300 def retrieve_from_cache(self):
301 """Try to retrieve the node's content from a cache
303 This method is called from multiple threads in a parallel build,
304 so only do thread safe stuff here. Do thread unsafe stuff in
307 Returns true iff the node was successfully retrieved.
312 # Taskmaster interface subsystem
315 def make_ready(self):
316 """Get a Node ready for evaluation.
318 This is called before the Taskmaster decides if the Node is
319 up-to-date or not. Overriding this method allows for a Node
320 subclass to be disambiguated if necessary, or for an implicit
321 source builder to be attached.
326 """Prepare for this Node to be built.
328 This is called after the Taskmaster has decided that the Node
329 is out-of-date and must be rebuilt, but before actually calling
330 the method to build the Node.
332 This default implementation checks that explicit or implicit
333 dependencies either exist or are derived, and initializes the
334 BuildInfo structure that will hold the information about how
335 this node is, uh, built.
337 (The existence of source files is checked separately by the
338 Executor, which aggregates checks for all of the targets built
339 by a specific action.)
341 Overriding this method allows for for a Node subclass to remove
342 the underlying file from the file system. Note that subclass
343 methods should call this base class method to get the child
344 check and the BuildInfo structure.
346 for d in self.depends:
348 msg = "Explicit dependency `%s' not found, needed by target `%s'."
349 raise SCons.Errors.StopError, msg % (d, self)
350 if not self.implicit is None:
351 for i in self.implicit:
353 msg = "Implicit dependency `%s' not found, needed by target `%s'."
354 raise SCons.Errors.StopError, msg % (i, self)
355 self.binfo = self.get_binfo()
357 def build(self, **kw):
358 """Actually build the node.
360 This is called by the Taskmaster after it's decided that the
361 Node is out-of-date and must be rebuilt, and after the prepare()
362 method has gotten everything, uh, prepared.
364 This method is called from multiple threads in a parallel build,
365 so only do thread safe stuff here. Do thread unsafe stuff
370 apply(self.get_executor(), (self,), kw)
371 except SCons.Errors.BuildError, e:
376 """Called just after this node is successfully built."""
378 # Clear the implicit dependency caches of any Nodes
379 # waiting for this Node to be built.
380 for parent in self.waiting_parents:
381 parent.implicit = None
385 self.ninfo.update(self)
388 """Called just after this node has been visited (with or
392 except AttributeError:
393 # Apparently this node doesn't need build info, so
394 # don't bother calculating or storing it.
397 self.ninfo.update(self)
404 def add_to_waiting_s_e(self, node):
405 self.waiting_s_e.add(node)
407 def add_to_waiting_parents(self, node):
409 Returns the number of nodes added to our waiting parents list:
410 1 if we add a unique waiting parent, 0 if not. (Note that the
411 returned values are intended to be used to increment a reference
412 count, so don't think you can "clean up" this function by using
413 True and False instead...)
415 wp = self.waiting_parents
421 def postprocess(self):
422 """Clean up anything we don't need to hang onto after we've
424 self.executor_cleanup()
425 self.waiting_parents = set()
428 """Completely clear a Node of all its cached state (so that it
429 can be re-evaluated by interfaces that do continuous integration
432 # The del_binfo() call here isn't necessary for normal execution,
433 # but is for interactive mode, where we might rebuild the same
434 # target and need to start from scratch.
436 self.clear_memoized_values()
437 self.ninfo = self.new_ninfo()
438 self.executor_cleanup()
440 delattr(self, '_calculated_sig')
441 except AttributeError:
445 def clear_memoized_values(self):
448 def builder_set(self, builder):
449 self.builder = builder
452 except AttributeError:
455 def has_builder(self):
456 """Return whether this Node has a builder or not.
458 In Boolean tests, this turns out to be a *lot* more efficient
459 than simply examining the builder attribute directly ("if
460 node.builder: ..."). When the builder attribute is examined
461 directly, it ends up calling __getattr__ for both the __len__
462 and __nonzero__ attributes on instances of our Builder Proxy
463 class(es), generating a bazillion extra calls and slowing
464 things down immensely.
468 except AttributeError:
469 # There was no explicit builder for this Node, so initialize
470 # the self.builder attribute to None now.
471 b = self.builder = None
474 def set_explicit(self, is_explicit):
475 self.is_explicit = is_explicit
477 def has_explicit_builder(self):
478 """Return whether this Node has an explicit builder
480 This allows an internal Builder created by SCons to be marked
481 non-explicit, so that it can be overridden by an explicit
482 builder that the user supplies (the canonical example being
485 return self.is_explicit
486 except AttributeError:
487 self.is_explicit = None
488 return self.is_explicit
490 def get_builder(self, default_builder=None):
491 """Return the set builder, or a specified default value"""
494 except AttributeError:
495 return default_builder
497 multiple_side_effect_has_builder = has_builder
499 def is_derived(self):
501 Returns true iff this node is derived (i.e. built).
503 This should return true only for nodes whose path should be in
504 the variant directory when duplicate=0 and should contribute their build
505 signatures when they are used as source files to other derived files. For
506 example: source with source builders are not derived in this sense,
507 and hence should not return true.
509 return self.has_builder() or self.side_effect
511 def alter_targets(self):
512 """Return a list of alternate targets for this Node.
516 def get_found_includes(self, env, scanner, path):
517 """Return the scanned include lines (implicit dependencies)
520 The default is no implicit dependencies. We expect this method
521 to be overridden by any subclass that can be scanned for
522 implicit dependencies.
526 def get_implicit_deps(self, env, scanner, path):
527 """Return a list of implicit dependencies for this node.
529 This method exists to handle recursive invocation of the scanner
530 on the implicit dependencies returned by the scanner, if the
531 scanner's recursive flag says that we should.
536 # Give the scanner a chance to select a more specific scanner
538 #scanner = scanner.select(self)
546 d = filter(lambda x, seen=seen: not seen.has_key(x),
547 n.get_found_includes(env, scanner, path))
552 nodes.extend(scanner.recurse_nodes(d))
556 def get_env_scanner(self, env, kw={}):
557 return env.get_scanner(self.scanner_key())
559 def get_target_scanner(self):
560 return self.builder.target_scanner
562 def get_source_scanner(self, node):
563 """Fetch the source scanner for the specified node
565 NOTE: "self" is the target being built, "node" is
566 the source file for which we want to fetch the scanner.
568 Implies self.has_builder() is true; again, expect to only be
569 called from locations where this is already verified.
571 This function may be called very often; it attempts to cache
572 the scanner found to improve performance.
576 scanner = self.builder.source_scanner
577 except AttributeError:
580 # The builder didn't have an explicit scanner, so go look up
581 # a scanner from env['SCANNERS'] based on the node's scanner
582 # key (usually the file extension).
583 scanner = self.get_env_scanner(self.get_build_env())
585 scanner = scanner.select(node)
588 def add_to_implicit(self, deps):
589 if not hasattr(self, 'implicit') or self.implicit is None:
591 self.implicit_set = set()
592 self._children_reset()
593 self._add_child(self.implicit, self.implicit_set, deps)
596 """Scan this node's dependents for implicit dependencies."""
597 # Don't bother scanning non-derived files, because we don't
598 # care what their dependencies are.
599 # Don't scan again, if we already have scanned.
600 if not self.implicit is None:
603 self.implicit_set = set()
604 self._children_reset()
605 if not self.has_builder():
608 build_env = self.get_build_env()
609 executor = self.get_executor()
611 # Here's where we implement --implicit-cache.
612 if implicit_cache and not implicit_deps_changed:
613 implicit = self.get_stored_implicit()
614 if implicit is not None:
615 # We now add the implicit dependencies returned from the
616 # stored .sconsign entry to have already been converted
617 # to Nodes for us. (We used to run them through a
618 # source_factory function here.)
620 # Update all of the targets with them. This
621 # essentially short-circuits an N*M scan of the
622 # sources for each individual target, which is a hell
623 # of a lot more efficient.
624 for tgt in executor.targets:
625 tgt.add_to_implicit(implicit)
627 if implicit_deps_unchanged or self.is_up_to_date():
629 # one of this node's sources has changed,
630 # so we must recalculate the implicit deps:
632 self.implicit_set = set()
634 # Have the executor scan the sources.
635 executor.scan_sources(self.builder.source_scanner)
637 # If there's a target scanner, have the executor scan the target
638 # node itself and associated targets that might be built.
639 scanner = self.get_target_scanner()
641 executor.scan_targets(scanner)
643 def scanner_key(self):
646 def select_scanner(self, scanner):
647 """Selects a scanner for this Node.
649 This is a separate method so it can be overridden by Node
650 subclasses (specifically, Node.FS.Dir) that *must* use their
651 own Scanner and don't select one the Scanner.Selector that's
652 configured for the target.
654 return scanner.select(self)
656 def env_set(self, env, safe=0):
657 if safe and self.env:
662 # SIGNATURE SUBSYSTEM
665 NodeInfo = NodeInfoBase
666 BuildInfo = BuildInfoBase
669 ninfo = self.NodeInfo(self)
675 except AttributeError:
676 self.ninfo = self.new_ninfo()
680 binfo = self.BuildInfo(self)
685 Fetch a node's build information.
687 node - the node whose sources will be collected
688 cache - alternate node to use for the signature cache
689 returns - the build signature
691 This no longer handles the recursive descent of the
692 node's children's signatures. We expect that they're
693 already built and updated by someone else, if that's
698 except AttributeError:
701 binfo = self.new_binfo()
704 executor = self.get_executor()
705 ignore_set = self.ignore_set
707 if self.has_builder():
708 binfo.bact = str(executor)
709 binfo.bactsig = SCons.Util.MD5signature(executor.get_contents())
711 if self._specific_sources:
713 for s in self.sources:
714 if s not in ignore_set:
717 sources = executor.get_unignored_sources(self.ignore)
725 bsourcesigs.append(s.get_ninfo())
726 binfo.bsources = bsources
727 binfo.bsourcesigs = bsourcesigs
729 depends = self.depends
732 if d not in ignore_set:
733 dependsigs.append(d.get_ninfo())
734 binfo.bdepends = depends
735 binfo.bdependsigs = dependsigs
737 implicit = self.implicit or []
740 if i not in ignore_set:
741 implicitsigs.append(i.get_ninfo())
742 binfo.bimplicit = implicit
743 binfo.bimplicitsigs = implicitsigs
748 """Delete the build info from this node."""
750 delattr(self, 'binfo')
751 except AttributeError:
756 return self.ninfo.csig
757 except AttributeError:
758 ninfo = self.get_ninfo()
759 ninfo.csig = SCons.Util.MD5signature(self.get_contents())
760 return self.ninfo.csig
762 def get_cachedir_csig(self):
763 return self.get_csig()
765 def store_info(self):
766 """Make the build signature permanent (that is, store it in the
767 .sconsign file or equivalent)."""
770 def do_not_store_info(self):
773 def get_stored_info(self):
776 def get_stored_implicit(self):
777 """Fetch the stored implicit dependencies"""
784 def set_precious(self, precious = 1):
785 """Set the Node's precious value."""
786 self.precious = precious
788 def set_noclean(self, noclean = 1):
789 """Set the Node's noclean value."""
790 # Make sure noclean is an integer so the --debug=stree
791 # output in Util.py can use it as an index.
792 self.noclean = noclean and 1 or 0
794 def set_nocache(self, nocache = 1):
795 """Set the Node's nocache value."""
796 # Make sure nocache is an integer so the --debug=stree
797 # output in Util.py can use it as an index.
798 self.nocache = nocache and 1 or 0
800 def set_always_build(self, always_build = 1):
801 """Set the Node's always_build value."""
802 self.always_build = always_build
805 """Does this node exists?"""
806 # All node exist by default:
810 """Does this node exist locally or in a repositiory?"""
811 # There are no repositories by default:
815 return not self.is_derived() and \
816 not self.linked and \
820 """Remove this Node: no-op by default."""
823 def add_dependency(self, depend):
824 """Adds dependencies."""
826 self._add_child(self.depends, self.depends_set, depend)
829 if SCons.Util.is_List(e):
833 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 def add_prerequisite(self, prerequisite):
836 """Adds prerequisites"""
837 self.prerequisites.extend(prerequisite)
838 self._children_reset()
840 def add_ignore(self, depend):
841 """Adds dependencies to ignore."""
843 self._add_child(self.ignore, self.ignore_set, depend)
846 if SCons.Util.is_List(e):
850 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 def add_source(self, source):
854 if self._specific_sources:
857 self._add_child(self.sources, self.sources_set, source)
860 if SCons.Util.is_List(e):
864 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 def _add_child(self, collection, set, child):
867 """Adds 'child' to 'collection', first checking 'set' to see if it's
869 #if type(child) is not type([]):
872 # if not isinstance(c, Node):
881 self._children_reset()
883 def set_specific_source(self, source):
884 self.add_source(source)
885 self._specific_sources = True
887 def add_wkid(self, wkid):
888 """Add a node to the list of kids waiting to be evaluated"""
889 if self.wkids != None:
890 self.wkids.append(wkid)
892 def _children_reset(self):
893 self.clear_memoized_values()
894 # We need to let the Executor clear out any calculated
895 # build info that it's cached so we can re-calculate it.
896 self.executor_cleanup()
898 memoizer_counters.append(SCons.Memoize.CountValue('_children_get'))
900 def _children_get(self):
902 return self._memo['children_get']
906 # The return list may contain duplicate Nodes, especially in
907 # source trees where there are a lot of repeated #includes
908 # of a tangle of .h files. Profiling shows, however, that
909 # eliminating the duplicates with a brute-force approach that
910 # preserves the order (that is, something like:
917 # takes more cycles than just letting the underlying methods
918 # hand back cached values if a Node's information is requested
919 # multiple times. (Other methods of removing duplicates, like
920 # using dictionary keys, lose the order, and the only ordered
921 # dictionary patterns I found all ended up using "not in"
922 # internally anyway...)
924 if self.implicit is None:
925 iter = chain(self.sources,self.depends)
927 iter = chain(self.sources, self.depends, self.implicit)
931 if i not in self.ignore_set:
934 if self.implicit is None:
935 children = self.sources + self.depends
937 children = self.sources + self.depends + self.implicit
939 self._memo['children_get'] = children
942 def all_children(self, scan=1):
943 """Return a list of all the node's direct children."""
947 # The return list may contain duplicate Nodes, especially in
948 # source trees where there are a lot of repeated #includes
949 # of a tangle of .h files. Profiling shows, however, that
950 # eliminating the duplicates with a brute-force approach that
951 # preserves the order (that is, something like:
958 # takes more cycles than just letting the underlying methods
959 # hand back cached values if a Node's information is requested
960 # multiple times. (Other methods of removing duplicates, like
961 # using dictionary keys, lose the order, and the only ordered
962 # dictionary patterns I found all ended up using "not in"
963 # internally anyway...)
964 if self.implicit is None:
965 return self.sources + self.depends
967 return self.sources + self.depends + self.implicit
969 def children(self, scan=1):
970 """Return a list of the node's direct children, minus those
971 that are ignored by this node."""
974 return self._children_get()
976 def set_state(self, state):
982 def state_has_changed(self, target, prev_ni):
983 return (self.state != SCons.Node.up_to_date)
988 import SCons.Defaults
989 env = SCons.Defaults.DefaultEnvironment()
992 def changed_since_last_build(self, target, prev_ni):
995 Must be overridden in a specific subclass to return True if this
996 Node (a dependency) has changed since the last time it was used
997 to build the specified target. prev_ni is this Node's state (for
998 example, its file timestamp, length, maybe content signature)
999 as of the last time the target was built.
1001 Note that this method is called through the dependency, not the
1002 target, because a dependency Node must be able to use its own
1003 logic to decide if it changed. For example, File Nodes need to
1004 obey if we're configured to use timestamps, but Python Value Nodes
1005 never use timestamps and always use the content. If this method
1006 were called through the target, then each Node's implementation
1007 of this method would have to have more complicated logic to
1008 handle all the different Node types on which it might depend.
1010 raise NotImplementedError
1012 def Decider(self, function):
1013 SCons.Util.AddMethod(self, function, 'changed_since_last_build')
1015 def changed(self, node=None):
1017 Returns if the node is up-to-date with respect to the BuildInfo
1018 stored last time it was built. The default behavior is to compare
1019 it against our own previously stored BuildInfo, but the stored
1020 BuildInfo from another Node (typically one in a Repository)
1021 can be used instead.
1023 Note that we now *always* check every dependency. We used to
1024 short-circuit the check by returning as soon as we detected
1025 any difference, but we now rely on checking every dependency
1026 to make sure that any necessary Node information (for example,
1027 the content signature of an #included .h file) is updated.
1030 if t: Trace('changed(%s [%s], %s)' % (self, classname(self), node))
1036 bi = node.get_stored_info().binfo
1037 then = bi.bsourcesigs + bi.bdependsigs + bi.bimplicitsigs
1038 children = self.children()
1040 diff = len(children) - len(then)
1042 # The old and new dependency lists are different lengths.
1043 # This always indicates that the Node must be rebuilt.
1044 # We also extend the old dependency list with enough None
1045 # entries to equal the new dependency list, for the benefit
1046 # of the loop below that updates node information.
1047 then.extend([None] * diff)
1048 if t: Trace(': old %s new %s' % (len(then), len(children)))
1051 for child, prev_ni in izip(children, then):
1052 if child.changed_since_last_build(self, prev_ni):
1053 if t: Trace(': %s changed' % child)
1056 contents = self.get_executor().get_contents()
1057 if self.has_builder():
1059 newsig = SCons.Util.MD5signature(contents)
1060 if bi.bactsig != newsig:
1061 if t: Trace(': bactsig %s != newsig %s' % (bi.bactsig, newsig))
1065 if t: Trace(': up to date')
1071 def is_up_to_date(self):
1072 """Default check for whether the Node is current: unknown Node
1073 subtypes are always out of date, so they will always get built."""
1076 def children_are_up_to_date(self):
1077 """Alternate check for whether the Node is current: If all of
1078 our children were up-to-date, then this Node was up-to-date, too.
1080 The SCons.Node.Alias and SCons.Node.Python.Value subclasses
1081 rebind their current() method to this method."""
1082 # Allow the children to calculate their signatures.
1083 self.binfo = self.get_binfo()
1084 if self.always_build:
1087 for kid in self.children(None):
1089 if s and (not state or s > state):
1091 return (state == 0 or state == SCons.Node.up_to_date)
1093 def is_literal(self):
1094 """Always pass the string representation of a Node to
1095 the command interpreter literally."""
1098 def render_include_tree(self):
1100 Return a text representation, suitable for displaying to the
1101 user, of the include tree for the sources of this node.
1103 if self.is_derived() and self.env:
1104 env = self.get_build_env()
1105 for s in self.sources:
1106 scanner = self.get_source_scanner(s)
1108 path = self.get_build_scanner_path(scanner)
1111 def f(node, env=env, scanner=scanner, path=path):
1112 return node.get_found_includes(env, scanner, path)
1113 return SCons.Util.render_tree(s, f, 1)
1117 def get_abspath(self):
1119 Return an absolute path to the Node. This will return simply
1120 str(Node) by default, but for Node types that have a concept of
1121 relative path, this might return something different.
1125 def for_signature(self):
1127 Return a string representation of the Node that will always
1128 be the same for this particular Node, no matter what. This
1129 is by contrast to the __str__() method, which might, for
1130 instance, return a relative path for a file Node. The purpose
1131 of this method is to generate a value to be used in signature
1132 calculation for the command line used to build a target, and
1133 we use this method instead of str() to avoid unnecessary
1134 rebuilds. This method does not need to return something that
1135 would actually work in a command line; it can return any kind of
1136 nonsense, so long as it does not change.
1140 def get_string(self, for_signature):
1141 """This is a convenience function designed primarily to be
1142 used in command generators (i.e., CommandGeneratorActions or
1143 Environment variables that are callable), which are called
1144 with a for_signature argument that is nonzero if the command
1145 generator is being called to generate a signature for the
1146 command line, which determines if we should rebuild or not.
1148 Such command generators should use this method in preference
1149 to str(Node) when converting a Node to a string, passing
1150 in the for_signature parameter, such that we will call
1151 Node.for_signature() or str(Node) properly, depending on whether
1152 we are calculating a signature or actually constructing a
1155 return self.for_signature()
1158 def get_subst_proxy(self):
1160 This method is expected to return an object that will function
1161 exactly like this Node, except that it implements any additional
1162 special features that we would like to be in effect for
1163 Environment variable substitution. The principle use is that
1164 some Nodes would like to implement a __getattr__() method,
1165 but putting that in the Node type itself has a tendency to kill
1166 performance. We instead put it in a proxy and return it from
1167 this method. It is legal for this method to return self
1168 if no new functionality is needed for Environment substitution.
1173 if not self.exists():
1174 return "building `%s' because it doesn't exist\n" % self
1176 if self.always_build:
1177 return "rebuilding `%s' because AlwaysBuild() is specified\n" % self
1179 old = self.get_stored_info()
1184 old.prepare_dependencies()
1187 old_bkids = old.bsources + old.bdepends + old.bimplicit
1188 old_bkidsigs = old.bsourcesigs + old.bdependsigs + old.bimplicitsigs
1189 except AttributeError:
1190 return "Cannot explain why `%s' is being rebuilt: No previous build information found\n" % self
1192 new = self.get_binfo()
1194 new_bkids = new.bsources + new.bdepends + new.bimplicit
1195 new_bkidsigs = new.bsourcesigs + new.bdependsigs + new.bimplicitsigs
1197 osig = dict(izip(old_bkids, old_bkidsigs))
1198 nsig = dict(izip(new_bkids, new_bkidsigs))
1200 # The sources and dependencies we'll want to report are all stored
1201 # as relative paths to this target's directory, but we want to
1202 # report them relative to the top-level SConstruct directory,
1203 # so we only print them after running them through this lambda
1204 # to turn them into the right relative Node and then return
1206 def stringify( s, E=self.dir.Entry ) :
1207 if hasattr( s, 'dir' ) :
1213 removed = filter(lambda x, nk=new_bkids: not x in nk, old_bkids)
1215 removed = map(stringify, removed)
1216 fmt = "`%s' is no longer a dependency\n"
1217 lines.extend(map(lambda s, fmt=fmt: fmt % s, removed))
1220 if not k in old_bkids:
1221 lines.append("`%s' is a new dependency\n" % stringify(k))
1222 elif k.changed_since_last_build(self, osig[k]):
1223 lines.append("`%s' changed\n" % stringify(k))
1225 if len(lines) == 0 and old_bkids != new_bkids:
1226 lines.append("the dependency order changed:\n" +
1227 "%sold: %s\n" % (' '*15, map(stringify, old_bkids)) +
1228 "%snew: %s\n" % (' '*15, map(stringify, new_bkids)))
1231 def fmt_with_title(title, strlines):
1232 lines = string.split(strlines, '\n')
1233 sep = '\n' + ' '*(15 + len(title))
1234 return ' '*15 + title + string.join(lines, sep) + '\n'
1235 if old.bactsig != new.bactsig:
1236 if old.bact == new.bact:
1237 lines.append("the contents of the build action changed\n" +
1238 fmt_with_title('action: ', new.bact))
1240 lines.append("the build action changed:\n" +
1241 fmt_with_title('old: ', old.bact) +
1242 fmt_with_title('new: ', new.bact))
1245 return "rebuilding `%s' for unknown reasons\n" % self
1247 preamble = "rebuilding `%s' because" % self
1249 return "%s %s" % (preamble, lines[0])
1251 lines = ["%s:\n" % preamble] + lines
1252 return string.join(lines, ' '*11)
1255 [].extend(UserList.UserList([]))
1257 # Python 1.5.2 doesn't allow a list to be extended by list-like
1258 # objects (such as UserList instances), so just punt and use
1263 class NodeList(UserList.UserList):
1265 return str(map(str, self.data))
1267 def get_children(node, parent): return node.children()
1268 def ignore_cycle(node, stack): pass
1269 def do_nothing(node, parent): pass
1272 """An iterator for walking a Node tree.
1274 This is depth-first, children are visited before the parent.
1275 The Walker object can be initialized with any node, and
1276 returns the next node on the descent with each next() call.
1277 'kids_func' is an optional function that will be called to
1278 get the children of a node instead of calling 'children'.
1279 'cycle_func' is an optional function that will be called
1280 when a cycle is detected.
1282 This class does not get caught in node cycles caused, for example,
1283 by C header file include loops.
1285 def __init__(self, node, kids_func=get_children,
1286 cycle_func=ignore_cycle,
1287 eval_func=do_nothing):
1288 self.kids_func = kids_func
1289 self.cycle_func = cycle_func
1290 self.eval_func = eval_func
1291 node.wkids = copy.copy(kids_func(node, None))
1293 self.history = {} # used to efficiently detect and avoid cycles
1294 self.history[node] = None
1297 """Return the next node for this walk of the tree.
1299 This function is intentionally iterative, not recursive,
1300 to sidestep any issues of stack size limitations.
1304 if self.stack[-1].wkids:
1305 node = self.stack[-1].wkids.pop(0)
1306 if not self.stack[-1].wkids:
1307 self.stack[-1].wkids = None
1308 if self.history.has_key(node):
1309 self.cycle_func(node, self.stack)
1311 node.wkids = copy.copy(self.kids_func(node, self.stack[-1]))
1312 self.stack.append(node)
1313 self.history[node] = None
1315 node = self.stack.pop()
1316 del self.history[node]
1319 parent = self.stack[-1]
1322 self.eval_func(node, parent)
1327 return not self.stack
1330 arg2nodes_lookups = []