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.
44 from __future__ import generators ### KEEP FOR COMPATIBILITY FIXERS
46 __revision__ = "__FILE__ __REVISION__ __DATE__ __DEVELOPER__"
49 from itertools import chain, izip
52 from SCons.Debug import logInstanceCreation
57 from SCons.Debug import Trace
60 return str(obj.__class__).split('.')[-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 push_to_cache(self):
301 """Try to push a node into a cache
305 def retrieve_from_cache(self):
306 """Try to retrieve the node's content from a cache
308 This method is called from multiple threads in a parallel build,
309 so only do thread safe stuff here. Do thread unsafe stuff in
312 Returns true iff the node was successfully retrieved.
317 # Taskmaster interface subsystem
320 def make_ready(self):
321 """Get a Node ready for evaluation.
323 This is called before the Taskmaster decides if the Node is
324 up-to-date or not. Overriding this method allows for a Node
325 subclass to be disambiguated if necessary, or for an implicit
326 source builder to be attached.
331 """Prepare for this Node to be built.
333 This is called after the Taskmaster has decided that the Node
334 is out-of-date and must be rebuilt, but before actually calling
335 the method to build the Node.
337 This default implementation checks that explicit or implicit
338 dependencies either exist or are derived, and initializes the
339 BuildInfo structure that will hold the information about how
340 this node is, uh, built.
342 (The existence of source files is checked separately by the
343 Executor, which aggregates checks for all of the targets built
344 by a specific action.)
346 Overriding this method allows for for a Node subclass to remove
347 the underlying file from the file system. Note that subclass
348 methods should call this base class method to get the child
349 check and the BuildInfo structure.
351 for d in self.depends:
353 msg = "Explicit dependency `%s' not found, needed by target `%s'."
354 raise SCons.Errors.StopError, msg % (d, self)
355 if self.implicit is not None:
356 for i in self.implicit:
358 msg = "Implicit dependency `%s' not found, needed by target `%s'."
359 raise SCons.Errors.StopError, msg % (i, self)
360 self.binfo = self.get_binfo()
362 def build(self, **kw):
363 """Actually build the node.
365 This is called by the Taskmaster after it's decided that the
366 Node is out-of-date and must be rebuilt, and after the prepare()
367 method has gotten everything, uh, prepared.
369 This method is called from multiple threads in a parallel build,
370 so only do thread safe stuff here. Do thread unsafe stuff
375 self.get_executor()(self, **kw)
376 except SCons.Errors.BuildError, e:
381 """Called just after this node is successfully built."""
383 # Clear the implicit dependency caches of any Nodes
384 # waiting for this Node to be built.
385 for parent in self.waiting_parents:
386 parent.implicit = None
390 self.ninfo.update(self)
393 """Called just after this node has been visited (with or
397 except AttributeError:
398 # Apparently this node doesn't need build info, so
399 # don't bother calculating or storing it.
402 self.ninfo.update(self)
409 def add_to_waiting_s_e(self, node):
410 self.waiting_s_e.add(node)
412 def add_to_waiting_parents(self, node):
414 Returns the number of nodes added to our waiting parents list:
415 1 if we add a unique waiting parent, 0 if not. (Note that the
416 returned values are intended to be used to increment a reference
417 count, so don't think you can "clean up" this function by using
418 True and False instead...)
420 wp = self.waiting_parents
426 def postprocess(self):
427 """Clean up anything we don't need to hang onto after we've
429 self.executor_cleanup()
430 self.waiting_parents = set()
433 """Completely clear a Node of all its cached state (so that it
434 can be re-evaluated by interfaces that do continuous integration
437 # The del_binfo() call here isn't necessary for normal execution,
438 # but is for interactive mode, where we might rebuild the same
439 # target and need to start from scratch.
441 self.clear_memoized_values()
442 self.ninfo = self.new_ninfo()
443 self.executor_cleanup()
445 delattr(self, '_calculated_sig')
446 except AttributeError:
450 def clear_memoized_values(self):
453 def builder_set(self, builder):
454 self.builder = builder
457 except AttributeError:
460 def has_builder(self):
461 """Return whether this Node has a builder or not.
463 In Boolean tests, this turns out to be a *lot* more efficient
464 than simply examining the builder attribute directly ("if
465 node.builder: ..."). When the builder attribute is examined
466 directly, it ends up calling __getattr__ for both the __len__
467 and __nonzero__ attributes on instances of our Builder Proxy
468 class(es), generating a bazillion extra calls and slowing
469 things down immensely.
473 except AttributeError:
474 # There was no explicit builder for this Node, so initialize
475 # the self.builder attribute to None now.
476 b = self.builder = None
479 def set_explicit(self, is_explicit):
480 self.is_explicit = is_explicit
482 def has_explicit_builder(self):
483 """Return whether this Node has an explicit builder
485 This allows an internal Builder created by SCons to be marked
486 non-explicit, so that it can be overridden by an explicit
487 builder that the user supplies (the canonical example being
490 return self.is_explicit
491 except AttributeError:
492 self.is_explicit = None
493 return self.is_explicit
495 def get_builder(self, default_builder=None):
496 """Return the set builder, or a specified default value"""
499 except AttributeError:
500 return default_builder
502 multiple_side_effect_has_builder = has_builder
504 def is_derived(self):
506 Returns true iff this node is derived (i.e. built).
508 This should return true only for nodes whose path should be in
509 the variant directory when duplicate=0 and should contribute their build
510 signatures when they are used as source files to other derived files. For
511 example: source with source builders are not derived in this sense,
512 and hence should not return true.
514 return self.has_builder() or self.side_effect
516 def alter_targets(self):
517 """Return a list of alternate targets for this Node.
521 def get_found_includes(self, env, scanner, path):
522 """Return the scanned include lines (implicit dependencies)
525 The default is no implicit dependencies. We expect this method
526 to be overridden by any subclass that can be scanned for
527 implicit dependencies.
531 def get_implicit_deps(self, env, scanner, path):
532 """Return a list of implicit dependencies for this node.
534 This method exists to handle recursive invocation of the scanner
535 on the implicit dependencies returned by the scanner, if the
536 scanner's recursive flag says that we should.
541 # Give the scanner a chance to select a more specific scanner
543 #scanner = scanner.select(self)
551 d = [x for x in n.get_found_includes(env, scanner, path) if x not in seen]
556 nodes.extend(scanner.recurse_nodes(d))
560 def get_env_scanner(self, env, kw={}):
561 return env.get_scanner(self.scanner_key())
563 def get_target_scanner(self):
564 return self.builder.target_scanner
566 def get_source_scanner(self, node):
567 """Fetch the source scanner for the specified node
569 NOTE: "self" is the target being built, "node" is
570 the source file for which we want to fetch the scanner.
572 Implies self.has_builder() is true; again, expect to only be
573 called from locations where this is already verified.
575 This function may be called very often; it attempts to cache
576 the scanner found to improve performance.
580 scanner = self.builder.source_scanner
581 except AttributeError:
584 # The builder didn't have an explicit scanner, so go look up
585 # a scanner from env['SCANNERS'] based on the node's scanner
586 # key (usually the file extension).
587 scanner = self.get_env_scanner(self.get_build_env())
589 scanner = scanner.select(node)
592 def add_to_implicit(self, deps):
593 if not hasattr(self, 'implicit') or self.implicit is None:
595 self.implicit_set = set()
596 self._children_reset()
597 self._add_child(self.implicit, self.implicit_set, deps)
600 """Scan this node's dependents for implicit dependencies."""
601 # Don't bother scanning non-derived files, because we don't
602 # care what their dependencies are.
603 # Don't scan again, if we already have scanned.
604 if self.implicit is not None:
607 self.implicit_set = set()
608 self._children_reset()
609 if not self.has_builder():
612 build_env = self.get_build_env()
613 executor = self.get_executor()
615 # Here's where we implement --implicit-cache.
616 if implicit_cache and not implicit_deps_changed:
617 implicit = self.get_stored_implicit()
618 if implicit is not None:
619 # We now add the implicit dependencies returned from the
620 # stored .sconsign entry to have already been converted
621 # to Nodes for us. (We used to run them through a
622 # source_factory function here.)
624 # Update all of the targets with them. This
625 # essentially short-circuits an N*M scan of the
626 # sources for each individual target, which is a hell
627 # of a lot more efficient.
628 for tgt in executor.get_all_targets():
629 tgt.add_to_implicit(implicit)
631 if implicit_deps_unchanged or self.is_up_to_date():
633 # one of this node's sources has changed,
634 # so we must recalculate the implicit deps:
636 self.implicit_set = set()
638 # Have the executor scan the sources.
639 executor.scan_sources(self.builder.source_scanner)
641 # If there's a target scanner, have the executor scan the target
642 # node itself and associated targets that might be built.
643 scanner = self.get_target_scanner()
645 executor.scan_targets(scanner)
647 def scanner_key(self):
650 def select_scanner(self, scanner):
651 """Selects a scanner for this Node.
653 This is a separate method so it can be overridden by Node
654 subclasses (specifically, Node.FS.Dir) that *must* use their
655 own Scanner and don't select one the Scanner.Selector that's
656 configured for the target.
658 return scanner.select(self)
660 def env_set(self, env, safe=0):
661 if safe and self.env:
666 # SIGNATURE SUBSYSTEM
669 NodeInfo = NodeInfoBase
670 BuildInfo = BuildInfoBase
673 ninfo = self.NodeInfo(self)
679 except AttributeError:
680 self.ninfo = self.new_ninfo()
684 binfo = self.BuildInfo(self)
689 Fetch a node's build information.
691 node - the node whose sources will be collected
692 cache - alternate node to use for the signature cache
693 returns - the build signature
695 This no longer handles the recursive descent of the
696 node's children's signatures. We expect that they're
697 already built and updated by someone else, if that's
702 except AttributeError:
705 binfo = self.new_binfo()
708 executor = self.get_executor()
709 ignore_set = self.ignore_set
711 if self.has_builder():
712 binfo.bact = str(executor)
713 binfo.bactsig = SCons.Util.MD5signature(executor.get_contents())
715 if self._specific_sources:
717 for s in self.sources:
718 if s not in ignore_set:
721 sources = executor.get_unignored_sources(self, self.ignore)
729 bsourcesigs.append(s.get_ninfo())
730 binfo.bsources = bsources
731 binfo.bsourcesigs = bsourcesigs
733 depends = self.depends
736 if d not in ignore_set:
737 dependsigs.append(d.get_ninfo())
738 binfo.bdepends = depends
739 binfo.bdependsigs = dependsigs
741 implicit = self.implicit or []
744 if i not in ignore_set:
745 implicitsigs.append(i.get_ninfo())
746 binfo.bimplicit = implicit
747 binfo.bimplicitsigs = implicitsigs
752 """Delete the build info from this node."""
754 delattr(self, 'binfo')
755 except AttributeError:
760 return self.ninfo.csig
761 except AttributeError:
762 ninfo = self.get_ninfo()
763 ninfo.csig = SCons.Util.MD5signature(self.get_contents())
764 return self.ninfo.csig
766 def get_cachedir_csig(self):
767 return self.get_csig()
769 def store_info(self):
770 """Make the build signature permanent (that is, store it in the
771 .sconsign file or equivalent)."""
774 def do_not_store_info(self):
777 def get_stored_info(self):
780 def get_stored_implicit(self):
781 """Fetch the stored implicit dependencies"""
788 def set_precious(self, precious = 1):
789 """Set the Node's precious value."""
790 self.precious = precious
792 def set_noclean(self, noclean = 1):
793 """Set the Node's noclean value."""
794 # Make sure noclean is an integer so the --debug=stree
795 # output in Util.py can use it as an index.
796 self.noclean = noclean and 1 or 0
798 def set_nocache(self, nocache = 1):
799 """Set the Node's nocache value."""
800 # Make sure nocache is an integer so the --debug=stree
801 # output in Util.py can use it as an index.
802 self.nocache = nocache and 1 or 0
804 def set_always_build(self, always_build = 1):
805 """Set the Node's always_build value."""
806 self.always_build = always_build
809 """Does this node exists?"""
810 # All node exist by default:
814 """Does this node exist locally or in a repositiory?"""
815 # There are no repositories by default:
819 return not self.is_derived() and \
820 not self.linked and \
824 """Remove this Node: no-op by default."""
827 def add_dependency(self, depend):
828 """Adds dependencies."""
830 self._add_child(self.depends, self.depends_set, depend)
833 if SCons.Util.is_List(e):
834 s = list(map(str, e))
837 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)))
839 def add_prerequisite(self, prerequisite):
840 """Adds prerequisites"""
841 self.prerequisites.extend(prerequisite)
842 self._children_reset()
844 def add_ignore(self, depend):
845 """Adds dependencies to ignore."""
847 self._add_child(self.ignore, self.ignore_set, depend)
850 if SCons.Util.is_List(e):
851 s = list(map(str, e))
854 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)))
856 def add_source(self, source):
858 if self._specific_sources:
861 self._add_child(self.sources, self.sources_set, source)
864 if SCons.Util.is_List(e):
865 s = list(map(str, e))
868 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)))
870 def _add_child(self, collection, set, child):
871 """Adds 'child' to 'collection', first checking 'set' to see if it's
873 #if type(child) is not type([]):
876 # if not isinstance(c, Node):
885 self._children_reset()
887 def set_specific_source(self, source):
888 self.add_source(source)
889 self._specific_sources = True
891 def add_wkid(self, wkid):
892 """Add a node to the list of kids waiting to be evaluated"""
893 if self.wkids is not None:
894 self.wkids.append(wkid)
896 def _children_reset(self):
897 self.clear_memoized_values()
898 # We need to let the Executor clear out any calculated
899 # build info that it's cached so we can re-calculate it.
900 self.executor_cleanup()
902 memoizer_counters.append(SCons.Memoize.CountValue('_children_get'))
904 def _children_get(self):
906 return self._memo['children_get']
910 # The return list may contain duplicate Nodes, especially in
911 # source trees where there are a lot of repeated #includes
912 # of a tangle of .h files. Profiling shows, however, that
913 # eliminating the duplicates with a brute-force approach that
914 # preserves the order (that is, something like:
921 # takes more cycles than just letting the underlying methods
922 # hand back cached values if a Node's information is requested
923 # multiple times. (Other methods of removing duplicates, like
924 # using dictionary keys, lose the order, and the only ordered
925 # dictionary patterns I found all ended up using "not in"
926 # internally anyway...)
928 if self.implicit is None:
929 iter = chain(self.sources,self.depends)
931 iter = chain(self.sources, self.depends, self.implicit)
935 if i not in self.ignore_set:
938 if self.implicit is None:
939 children = self.sources + self.depends
941 children = self.sources + self.depends + self.implicit
943 self._memo['children_get'] = children
946 def all_children(self, scan=1):
947 """Return a list of all the node's direct children."""
951 # The return list may contain duplicate Nodes, especially in
952 # source trees where there are a lot of repeated #includes
953 # of a tangle of .h files. Profiling shows, however, that
954 # eliminating the duplicates with a brute-force approach that
955 # preserves the order (that is, something like:
962 # takes more cycles than just letting the underlying methods
963 # hand back cached values if a Node's information is requested
964 # multiple times. (Other methods of removing duplicates, like
965 # using dictionary keys, lose the order, and the only ordered
966 # dictionary patterns I found all ended up using "not in"
967 # internally anyway...)
968 if self.implicit is None:
969 return self.sources + self.depends
971 return self.sources + self.depends + self.implicit
973 def children(self, scan=1):
974 """Return a list of the node's direct children, minus those
975 that are ignored by this node."""
978 return self._children_get()
980 def set_state(self, state):
986 def state_has_changed(self, target, prev_ni):
987 return (self.state != SCons.Node.up_to_date)
992 import SCons.Defaults
993 env = SCons.Defaults.DefaultEnvironment()
996 def changed_since_last_build(self, target, prev_ni):
999 Must be overridden in a specific subclass to return True if this
1000 Node (a dependency) has changed since the last time it was used
1001 to build the specified target. prev_ni is this Node's state (for
1002 example, its file timestamp, length, maybe content signature)
1003 as of the last time the target was built.
1005 Note that this method is called through the dependency, not the
1006 target, because a dependency Node must be able to use its own
1007 logic to decide if it changed. For example, File Nodes need to
1008 obey if we're configured to use timestamps, but Python Value Nodes
1009 never use timestamps and always use the content. If this method
1010 were called through the target, then each Node's implementation
1011 of this method would have to have more complicated logic to
1012 handle all the different Node types on which it might depend.
1014 raise NotImplementedError
1016 def Decider(self, function):
1017 SCons.Util.AddMethod(self, function, 'changed_since_last_build')
1019 def changed(self, node=None):
1021 Returns if the node is up-to-date with respect to the BuildInfo
1022 stored last time it was built. The default behavior is to compare
1023 it against our own previously stored BuildInfo, but the stored
1024 BuildInfo from another Node (typically one in a Repository)
1025 can be used instead.
1027 Note that we now *always* check every dependency. We used to
1028 short-circuit the check by returning as soon as we detected
1029 any difference, but we now rely on checking every dependency
1030 to make sure that any necessary Node information (for example,
1031 the content signature of an #included .h file) is updated.
1034 if t: Trace('changed(%s [%s], %s)' % (self, classname(self), node))
1040 bi = node.get_stored_info().binfo
1041 then = bi.bsourcesigs + bi.bdependsigs + bi.bimplicitsigs
1042 children = self.children()
1044 diff = len(children) - len(then)
1046 # The old and new dependency lists are different lengths.
1047 # This always indicates that the Node must be rebuilt.
1048 # We also extend the old dependency list with enough None
1049 # entries to equal the new dependency list, for the benefit
1050 # of the loop below that updates node information.
1051 then.extend([None] * diff)
1052 if t: Trace(': old %s new %s' % (len(then), len(children)))
1055 for child, prev_ni in izip(children, then):
1056 if child.changed_since_last_build(self, prev_ni):
1057 if t: Trace(': %s changed' % child)
1060 contents = self.get_executor().get_contents()
1061 if self.has_builder():
1063 newsig = SCons.Util.MD5signature(contents)
1064 if bi.bactsig != newsig:
1065 if t: Trace(': bactsig %s != newsig %s' % (bi.bactsig, newsig))
1069 if t: Trace(': up to date')
1075 def is_up_to_date(self):
1076 """Default check for whether the Node is current: unknown Node
1077 subtypes are always out of date, so they will always get built."""
1080 def children_are_up_to_date(self):
1081 """Alternate check for whether the Node is current: If all of
1082 our children were up-to-date, then this Node was up-to-date, too.
1084 The SCons.Node.Alias and SCons.Node.Python.Value subclasses
1085 rebind their current() method to this method."""
1086 # Allow the children to calculate their signatures.
1087 self.binfo = self.get_binfo()
1088 if self.always_build:
1091 for kid in self.children(None):
1093 if s and (not state or s > state):
1095 return (state == 0 or state == SCons.Node.up_to_date)
1097 def is_literal(self):
1098 """Always pass the string representation of a Node to
1099 the command interpreter literally."""
1102 def render_include_tree(self):
1104 Return a text representation, suitable for displaying to the
1105 user, of the include tree for the sources of this node.
1107 if self.is_derived() and self.env:
1108 env = self.get_build_env()
1109 for s in self.sources:
1110 scanner = self.get_source_scanner(s)
1112 path = self.get_build_scanner_path(scanner)
1115 def f(node, env=env, scanner=scanner, path=path):
1116 return node.get_found_includes(env, scanner, path)
1117 return SCons.Util.render_tree(s, f, 1)
1121 def get_abspath(self):
1123 Return an absolute path to the Node. This will return simply
1124 str(Node) by default, but for Node types that have a concept of
1125 relative path, this might return something different.
1129 def for_signature(self):
1131 Return a string representation of the Node that will always
1132 be the same for this particular Node, no matter what. This
1133 is by contrast to the __str__() method, which might, for
1134 instance, return a relative path for a file Node. The purpose
1135 of this method is to generate a value to be used in signature
1136 calculation for the command line used to build a target, and
1137 we use this method instead of str() to avoid unnecessary
1138 rebuilds. This method does not need to return something that
1139 would actually work in a command line; it can return any kind of
1140 nonsense, so long as it does not change.
1144 def get_string(self, for_signature):
1145 """This is a convenience function designed primarily to be
1146 used in command generators (i.e., CommandGeneratorActions or
1147 Environment variables that are callable), which are called
1148 with a for_signature argument that is nonzero if the command
1149 generator is being called to generate a signature for the
1150 command line, which determines if we should rebuild or not.
1152 Such command generators should use this method in preference
1153 to str(Node) when converting a Node to a string, passing
1154 in the for_signature parameter, such that we will call
1155 Node.for_signature() or str(Node) properly, depending on whether
1156 we are calculating a signature or actually constructing a
1159 return self.for_signature()
1162 def get_subst_proxy(self):
1164 This method is expected to return an object that will function
1165 exactly like this Node, except that it implements any additional
1166 special features that we would like to be in effect for
1167 Environment variable substitution. The principle use is that
1168 some Nodes would like to implement a __getattr__() method,
1169 but putting that in the Node type itself has a tendency to kill
1170 performance. We instead put it in a proxy and return it from
1171 this method. It is legal for this method to return self
1172 if no new functionality is needed for Environment substitution.
1177 if not self.exists():
1178 return "building `%s' because it doesn't exist\n" % self
1180 if self.always_build:
1181 return "rebuilding `%s' because AlwaysBuild() is specified\n" % self
1183 old = self.get_stored_info()
1188 old.prepare_dependencies()
1191 old_bkids = old.bsources + old.bdepends + old.bimplicit
1192 old_bkidsigs = old.bsourcesigs + old.bdependsigs + old.bimplicitsigs
1193 except AttributeError:
1194 return "Cannot explain why `%s' is being rebuilt: No previous build information found\n" % self
1196 new = self.get_binfo()
1198 new_bkids = new.bsources + new.bdepends + new.bimplicit
1199 new_bkidsigs = new.bsourcesigs + new.bdependsigs + new.bimplicitsigs
1201 osig = dict(izip(old_bkids, old_bkidsigs))
1202 nsig = dict(izip(new_bkids, new_bkidsigs))
1204 # The sources and dependencies we'll want to report are all stored
1205 # as relative paths to this target's directory, but we want to
1206 # report them relative to the top-level SConstruct directory,
1207 # so we only print them after running them through this lambda
1208 # to turn them into the right relative Node and then return
1210 def stringify( s, E=self.dir.Entry ) :
1211 if hasattr( s, 'dir' ) :
1217 removed = [x for x in old_bkids if not x in new_bkids]
1219 removed = list(map(stringify, removed))
1220 fmt = "`%s' is no longer a dependency\n"
1221 lines.extend([fmt % s for s in removed])
1224 if not k in old_bkids:
1225 lines.append("`%s' is a new dependency\n" % stringify(k))
1226 elif k.changed_since_last_build(self, osig[k]):
1227 lines.append("`%s' changed\n" % stringify(k))
1229 if len(lines) == 0 and old_bkids != new_bkids:
1230 lines.append("the dependency order changed:\n" +
1231 "%sold: %s\n" % (' '*15, list(map(stringify, old_bkids))) +
1232 "%snew: %s\n" % (' '*15, list(map(stringify, new_bkids))))
1235 def fmt_with_title(title, strlines):
1236 lines = strlines.split('\n')
1237 sep = '\n' + ' '*(15 + len(title))
1238 return ' '*15 + title + sep.join(lines) + '\n'
1239 if old.bactsig != new.bactsig:
1240 if old.bact == new.bact:
1241 lines.append("the contents of the build action changed\n" +
1242 fmt_with_title('action: ', new.bact))
1244 lines.append("the build action changed:\n" +
1245 fmt_with_title('old: ', old.bact) +
1246 fmt_with_title('new: ', new.bact))
1249 return "rebuilding `%s' for unknown reasons\n" % self
1251 preamble = "rebuilding `%s' because" % self
1253 return "%s %s" % (preamble, lines[0])
1255 lines = ["%s:\n" % preamble] + lines
1256 return ( ' '*11).join(lines)
1259 [].extend(UserList.UserList([]))
1261 # Python 1.5.2 doesn't allow a list to be extended by list-like
1262 # objects (such as UserList instances), so just punt and use
1267 class NodeList(UserList.UserList):
1269 return str(list(map(str, self.data)))
1271 def get_children(node, parent): return node.children()
1272 def ignore_cycle(node, stack): pass
1273 def do_nothing(node, parent): pass
1276 """An iterator for walking a Node tree.
1278 This is depth-first, children are visited before the parent.
1279 The Walker object can be initialized with any node, and
1280 returns the next node on the descent with each next() call.
1281 'kids_func' is an optional function that will be called to
1282 get the children of a node instead of calling 'children'.
1283 'cycle_func' is an optional function that will be called
1284 when a cycle is detected.
1286 This class does not get caught in node cycles caused, for example,
1287 by C header file include loops.
1289 def __init__(self, node, kids_func=get_children,
1290 cycle_func=ignore_cycle,
1291 eval_func=do_nothing):
1292 self.kids_func = kids_func
1293 self.cycle_func = cycle_func
1294 self.eval_func = eval_func
1295 node.wkids = copy.copy(kids_func(node, None))
1297 self.history = {} # used to efficiently detect and avoid cycles
1298 self.history[node] = None
1301 """Return the next node for this walk of the tree.
1303 This function is intentionally iterative, not recursive,
1304 to sidestep any issues of stack size limitations.
1308 if self.stack[-1].wkids:
1309 node = self.stack[-1].wkids.pop(0)
1310 if not self.stack[-1].wkids:
1311 self.stack[-1].wkids = None
1312 if node in self.history:
1313 self.cycle_func(node, self.stack)
1315 node.wkids = copy.copy(self.kids_func(node, self.stack[-1]))
1316 self.stack.append(node)
1317 self.history[node] = None
1319 node = self.stack.pop()
1320 del self.history[node]
1323 parent = self.stack[-1]
1326 self.eval_func(node, parent)
1331 return not self.stack
1334 arg2nodes_lookups = []
1338 # indent-tabs-mode:nil
1340 # vim: set expandtab tabstop=4 shiftwidth=4: