3 Builder object subsystem.
5 A Builder object is a callable that encapsulates information about how
6 to execute actions to create a target Node (file) from source Nodes
7 (files), and how to create those dependencies for tracking.
9 The main entry point here is the Builder() factory method. This provides
10 a procedural interface that creates the right underlying Builder object
11 based on the keyword arguments supplied and the types of the arguments.
13 The goal is for this external interface to be simple enough that the
14 vast majority of users can create new Builders as necessary to support
15 building new types of files in their configurations, without having to
16 dive any deeper into this subsystem.
18 The base class here is BuilderBase. This is a concrete base class which
19 does, in fact, represent the Builder objects that we (or users) create.
21 There is also a proxy that looks like a Builder:
25 This proxies for a Builder with an action that is actually a
26 dictionary that knows how to map file suffixes to a specific
27 action. This is so that we can invoke different actions
28 (compilers, compile options) for different flavors of source
31 Builders and their proxies have the following public interface methods
32 used by other modules:
35 THE public interface. Calling a Builder object (with the
36 use of internal helper methods) sets up the target and source
37 dependencies, appropriate mapping to a specific action, and the
38 environment manipulation necessary for overridden construction
39 variable. This also takes care of warning about possible mistakes
43 Adds an emitter for a specific file suffix, used by some Tool
44 modules to specify that (for example) a yacc invocation on a .y
45 can create a .h *and* a .c file.
48 Adds an action for a specific file suffix, heavily used by
49 Tool modules to add their specific action(s) for turning
50 a source file into an object file to the global static
51 and shared object file Builders.
53 There are the following methods for internal use within this module:
56 The internal method that handles the heavily lifting when a
57 Builder is called. This is used so that the __call__() methods
58 can set up warning about possible mistakes in keyword-argument
59 overrides, and *then* execute all of the steps necessary so that
60 the warnings only occur once.
63 Returns the Builder's name within a specific Environment,
64 primarily used to try to return helpful information in error
72 Miscellaneous stuff for handling the prefix and suffix
73 manipulation we use in turning source file names into target
79 # Copyright (c) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008 The SCons Foundation
81 # Permission is hereby granted, free of charge, to any person obtaining
82 # a copy of this software and associated documentation files (the
83 # "Software"), to deal in the Software without restriction, including
84 # without limitation the rights to use, copy, modify, merge, publish,
85 # distribute, sublicense, and/or sell copies of the Software, and to
86 # permit persons to whom the Software is furnished to do so, subject to
87 # the following conditions:
89 # The above copyright notice and this permission notice shall be included
90 # in all copies or substantial portions of the Software.
92 # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY
93 # KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
94 # WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
95 # NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
96 # LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
97 # OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
98 # WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
101 __revision__ = "src/engine/SCons/Builder.py 3842 2008/12/20 22:59:52 scons"
107 from SCons.Debug import logInstanceCreation
108 from SCons.Errors import InternalError, UserError
109 import SCons.Executor
114 import SCons.Warnings
121 class DictCmdGenerator(SCons.Util.Selector):
122 """This is a callable class that can be used as a
123 command generator function. It holds on to a dictionary
124 mapping file suffixes to Actions. It uses that dictionary
125 to return the proper action based on the file suffix of
128 def __init__(self, dict=None, source_ext_match=1):
129 SCons.Util.Selector.__init__(self, dict)
130 self.source_ext_match = source_ext_match
132 def src_suffixes(self):
135 def add_action(self, suffix, action):
136 """Add a suffix-action pair to the mapping.
138 self[suffix] = action
140 def __call__(self, target, source, env, for_signature):
144 if self.source_ext_match:
146 for src in map(str, source):
147 my_ext = SCons.Util.splitext(src)[1]
148 if ext and my_ext != ext:
149 raise UserError("While building `%s' from `%s': Cannot build multiple sources with different extensions: %s, %s" % (repr(map(str, target)), src, ext, my_ext))
152 ext = SCons.Util.splitext(str(source[0]))[1]
155 raise UserError("While building `%s': Cannot deduce file extension from source files: %s" % (repr(map(str, target)), repr(map(str, source))))
158 ret = SCons.Util.Selector.__call__(self, env, source)
160 raise UserError("Ambiguous suffixes after environment substitution: %s == %s == %s" % (e[0], e[1], e[2]))
162 raise UserError("While building `%s' from `%s': Don't know how to build from a source file with suffix `%s'. Expected a suffix in this list: %s." % \
163 (repr(map(str, target)), repr(map(str, source)), ext, repr(self.keys())))
166 class CallableSelector(SCons.Util.Selector):
167 """A callable dictionary that will, in turn, call the value it
169 def __call__(self, env, source):
170 value = SCons.Util.Selector.__call__(self, env, source)
172 value = value(env, source)
175 class DictEmitter(SCons.Util.Selector):
176 """A callable dictionary that maps file suffixes to emitters.
177 When called, it finds the right emitter in its dictionary for the
178 suffix of the first source file, and calls that emitter to get the
179 right lists of targets and sources to return. If there's no emitter
180 for the suffix in its dictionary, the original target and source are
183 def __call__(self, target, source, env):
184 emitter = SCons.Util.Selector.__call__(self, env, source)
186 target, source = emitter(target, source, env)
187 return (target, source)
189 class ListEmitter(UserList.UserList):
190 """A callable list of emitters that calls each in sequence,
191 returning the result.
193 def __call__(self, target, source, env):
195 target, source = e(target, source, env)
196 return (target, source)
198 # These are a common errors when calling a Builder;
199 # they are similar to the 'target' and 'source' keyword args to builders,
200 # so we issue warnings when we see them. The warnings can, of course,
202 misleading_keywords = {
203 'targets' : 'target',
204 'sources' : 'source',
207 class OverrideWarner(UserDict.UserDict):
208 """A class for warning about keyword arguments that we use as
209 overrides in a Builder call.
211 This class exists to handle the fact that a single Builder call
212 can actually invoke multiple builders. This class only emits the
213 warnings once, no matter how many Builders are invoked.
215 def __init__(self, dict):
216 UserDict.UserDict.__init__(self, dict)
217 if __debug__: logInstanceCreation(self, 'Builder.OverrideWarner')
218 self.already_warned = None
220 if self.already_warned:
222 for k in self.keys():
223 if misleading_keywords.has_key(k):
224 alt = misleading_keywords[k]
225 msg = "Did you mean to use `%s' instead of `%s'?" % (alt, k)
226 SCons.Warnings.warn(SCons.Warnings.MisleadingKeywordsWarning, msg)
227 self.already_warned = 1
230 """A factory for builder objects."""
232 if kw.has_key('generator'):
233 if kw.has_key('action'):
234 raise UserError, "You must not specify both an action and a generator."
235 kw['action'] = SCons.Action.CommandGeneratorAction(kw['generator'], {})
237 elif kw.has_key('action'):
238 source_ext_match = kw.get('source_ext_match', 1)
239 if kw.has_key('source_ext_match'):
240 del kw['source_ext_match']
241 if SCons.Util.is_Dict(kw['action']):
242 composite = DictCmdGenerator(kw['action'], source_ext_match)
243 kw['action'] = SCons.Action.CommandGeneratorAction(composite, {})
244 kw['src_suffix'] = composite.src_suffixes()
246 kw['action'] = SCons.Action.Action(kw['action'])
248 if kw.has_key('emitter'):
249 emitter = kw['emitter']
250 if SCons.Util.is_String(emitter):
251 # This allows users to pass in an Environment
252 # variable reference (like "$FOO") as an emitter.
253 # We will look in that Environment variable for
254 # a callable to use as the actual emitter.
255 var = SCons.Util.get_environment_var(emitter)
257 raise UserError, "Supplied emitter '%s' does not appear to refer to an Environment variable" % emitter
258 kw['emitter'] = EmitterProxy(var)
259 elif SCons.Util.is_Dict(emitter):
260 kw['emitter'] = DictEmitter(emitter)
261 elif SCons.Util.is_List(emitter):
262 kw['emitter'] = ListEmitter(emitter)
264 result = apply(BuilderBase, (), kw)
266 if not composite is None:
267 result = CompositeBuilder(result, composite)
271 def _node_errors(builder, env, tlist, slist):
272 """Validate that the lists of target and source nodes are
273 legal for this builder and environment. Raise errors or
274 issue warnings as appropriate.
277 # First, figure out if there are any errors in the way the targets
281 raise UserError, "Multiple ways to build the same target were specified for: %s" % t
282 if t.has_explicit_builder():
283 if not t.env is None and not t.env is env:
284 action = t.builder.action
285 t_contents = action.get_contents(tlist, slist, t.env)
286 contents = action.get_contents(tlist, slist, env)
288 if t_contents == contents:
289 msg = "Two different environments were specified for target %s,\n\tbut they appear to have the same action: %s" % (t, action.genstring(tlist, slist, t.env))
290 SCons.Warnings.warn(SCons.Warnings.DuplicateEnvironmentWarning, msg)
292 msg = "Two environments with different actions were specified for the same target: %s" % t
295 if t.builder != builder:
296 msg = "Two different builders (%s and %s) were specified for the same target: %s" % (t.builder.get_name(env), builder.get_name(env), t)
298 if t.get_executor().targets != tlist:
299 msg = "Two different target lists have a target in common: %s (from %s and from %s)" % (t, map(str, t.get_executor().targets), map(str, tlist))
301 elif t.sources != slist:
302 msg = "Multiple ways to build the same target were specified for: %s (from %s and from %s)" % (t, map(str, t.sources), map(str, slist))
305 if builder.single_source:
307 raise UserError, "More than one source given for single-source builder: targets=%s sources=%s" % (map(str,tlist), map(str,slist))
310 """This is a callable class that can act as a
311 Builder emitter. It holds on to a string that
312 is a key into an Environment dictionary, and will
313 look there at actual build time to see if it holds
314 a callable. If so, we will call that as the actual
316 def __init__(self, var):
317 self.var = SCons.Util.to_String(var)
319 def __call__(self, target, source, env):
322 # Recursively substitute the variable.
323 # We can't use env.subst() because it deals only
324 # in strings. Maybe we should change that?
325 while SCons.Util.is_String(emitter) and env.has_key(emitter):
326 emitter = env[emitter]
327 if callable(emitter):
328 target, source = emitter(target, source, env)
329 elif SCons.Util.is_List(emitter):
331 target, source = e(target, source, env)
333 return (target, source)
336 def __cmp__(self, other):
337 return cmp(self.var, other.var)
340 """Base class for Builders, objects that create output
341 nodes (files) from input nodes (files).
344 if SCons.Memoize.use_memoizer:
345 __metaclass__ = SCons.Memoize.Memoized_Metaclass
347 memoizer_counters = []
349 def __init__(self, action = None,
353 target_factory = None,
354 source_factory = None,
355 target_scanner = None,
356 source_scanner = None,
365 ensure_suffix = False,
367 if __debug__: logInstanceCreation(self, 'Builder.BuilderBase')
371 if SCons.Util.is_Dict(prefix):
372 prefix = CallableSelector(prefix)
374 if SCons.Util.is_Dict(suffix):
375 suffix = CallableSelector(suffix)
377 self.single_source = single_source
378 if overrides.has_key('overrides'):
379 SCons.Warnings.warn(SCons.Warnings.DeprecatedWarning,
380 "The \"overrides\" keyword to Builder() creation has been deprecated;\n" +\
381 "\tspecify the items as keyword arguments to the Builder() call instead.")
382 overrides.update(overrides['overrides'])
383 del overrides['overrides']
384 if overrides.has_key('scanner'):
385 SCons.Warnings.warn(SCons.Warnings.DeprecatedWarning,
386 "The \"scanner\" keyword to Builder() creation has been deprecated;\n"
387 "\tuse: source_scanner or target_scanner as appropriate.")
388 del overrides['scanner']
389 self.overrides = overrides
391 self.set_suffix(suffix)
392 self.set_src_suffix(src_suffix)
393 self.ensure_suffix = ensure_suffix
395 self.target_factory = target_factory
396 self.source_factory = source_factory
397 self.target_scanner = target_scanner
398 self.source_scanner = source_scanner
400 self.emitter = emitter
402 # Optional Builder name should only be used for Builders
403 # that don't get attached to construction environments.
406 self.executor_kw = {}
407 if not chdir is _null:
408 self.executor_kw['chdir'] = chdir
409 self.is_explicit = is_explicit
411 if src_builder is None:
413 elif not SCons.Util.is_List(src_builder):
414 src_builder = [ src_builder ]
415 self.src_builder = src_builder
417 def __nonzero__(self):
418 raise InternalError, "Do not test for the Node.builder attribute directly; use Node.has_builder() instead"
420 def get_name(self, env):
421 """Attempts to get the name of the Builder.
423 Look at the BUILDERS variable of env, expecting it to be a
424 dictionary containing this Builder, and return the key of the
425 dictionary. If there's no key, then return a directly-configured
426 name (if there is one) or the name of the class (by default)."""
429 index = env['BUILDERS'].values().index(self)
430 return env['BUILDERS'].keys()[index]
431 except (AttributeError, KeyError, TypeError, ValueError):
434 except AttributeError:
435 return str(self.__class__)
437 def __cmp__(self, other):
438 return cmp(self.__dict__, other.__dict__)
440 def splitext(self, path, env=None):
444 matchsuf = filter(lambda S,path=path: path[-len(S):] == S,
445 self.src_suffixes(env))
447 suf = max(map(None, map(len, matchsuf), matchsuf))[1]
448 return [path[:-len(suf)], path[-len(suf):]]
449 return SCons.Util.splitext(path)
451 def get_single_executor(self, env, tlist, slist, executor_kw):
453 raise UserError, "Builder %s must have an action to build %s."%(self.get_name(env or self.env), map(str,tlist))
454 return self.action.get_executor(env or self.env,
455 [], # env already has overrides
460 def get_multi_executor(self, env, tlist, slist, executor_kw):
462 executor = tlist[0].get_executor(create = 0)
463 except (AttributeError, IndexError):
464 return self.get_single_executor(env, tlist, slist, executor_kw)
466 executor.add_sources(slist)
469 def _adjustixes(self, files, pre, suf, ensure_suffix=False):
473 if not SCons.Util.is_List(files):
477 if SCons.Util.is_String(f):
478 f = SCons.Util.adjustixes(f, pre, suf, ensure_suffix)
482 def _create_nodes(self, env, target = None, source = None):
483 """Create and return lists of target and source nodes.
485 src_suf = self.get_src_suffix(env)
487 target_factory = env.get_factory(self.target_factory)
488 source_factory = env.get_factory(self.source_factory)
490 source = self._adjustixes(source, None, src_suf)
491 slist = env.arg2nodes(source, source_factory)
493 pre = self.get_prefix(env, slist)
494 suf = self.get_suffix(env, slist)
498 t_from_s = slist[0].target_from_source
499 except AttributeError:
500 raise UserError("Do not know how to create a target from source `%s'" % slist[0])
504 splitext = lambda S,self=self,env=env: self.splitext(S,env)
505 tlist = [ t_from_s(pre, suf, splitext) ]
507 target = self._adjustixes(target, pre, suf, self.ensure_suffix)
508 tlist = env.arg2nodes(target, target_factory, target=target, source=source)
511 # The emitter is going to do str(node), but because we're
512 # being called *from* a builder invocation, the new targets
513 # don't yet have a builder set on them and will look like
514 # source files. Fool the emitter's str() calls by setting
515 # up a temporary builder on the new targets.
518 if not t.is_derived():
520 new_targets.append(t)
522 orig_tlist = tlist[:]
523 orig_slist = slist[:]
525 target, source = self.emitter(target=tlist, source=slist, env=env)
527 # Now delete the temporary builders that we attached to any
528 # new targets, so that _node_errors() doesn't do weird stuff
529 # to them because it thinks they already have builders.
530 for t in new_targets:
531 if t.builder is self:
532 # Only delete the temporary builder if the emitter
533 # didn't change it on us.
536 # Have to call arg2nodes yet again, since it is legal for
537 # emitters to spit out strings as well as Node instances.
538 tlist = env.arg2nodes(target, target_factory,
539 target=orig_tlist, source=orig_slist)
540 slist = env.arg2nodes(source, source_factory,
541 target=orig_tlist, source=orig_slist)
545 def _execute(self, env, target, source, overwarn={}, executor_kw={}):
546 # We now assume that target and source are lists or None.
548 source = self.src_builder_sources(env, source, overwarn)
550 if self.single_source and len(source) > 1 and target is None:
552 if target is None: target = [None]*len(source)
553 for tgt, src in zip(target, source):
554 if not tgt is None: tgt = [tgt]
555 if not src is None: src = [src]
556 result.extend(self._execute(env, tgt, src, overwarn))
557 return SCons.Node.NodeList(result)
561 tlist, slist = self._create_nodes(env, target, source)
563 # Check for errors with the specified target/source lists.
564 _node_errors(self, env, tlist, slist)
566 # The targets are fine, so find or make the appropriate Executor to
567 # build this particular list of targets from this particular list of
570 get_executor = self.get_multi_executor
572 get_executor = self.get_single_executor
573 executor = get_executor(env, tlist, slist, executor_kw)
575 # Now set up the relevant information in the target Nodes themselves.
577 t.cwd = env.fs.getcwd()
581 t.set_executor(executor)
582 t.set_explicit(self.is_explicit)
584 return SCons.Node.NodeList(tlist)
586 def __call__(self, env, target=None, source=None, chdir=_null, **kw):
587 # We now assume that target and source are lists or None.
588 # The caller (typically Environment.BuilderWrapper) is
589 # responsible for converting any scalar values to lists.
591 ekw = self.executor_kw
593 ekw = self.executor_kw.copy()
596 if kw.has_key('srcdir'):
597 def prependDirIfRelative(f, srcdir=kw['srcdir']):
599 if SCons.Util.is_String(f) and not os.path.isabs(f):
600 f = os.path.join(srcdir, f)
602 if not SCons.Util.is_List(source):
604 source = map(prependDirIfRelative, source)
607 env_kw = self.overrides.copy()
612 env_kw = self.overrides
613 env = env.Override(env_kw)
614 return self._execute(env, target, source, OverrideWarner(kw), ekw)
616 def adjust_suffix(self, suff):
617 if suff and not suff[0] in [ '.', '_', '$' ]:
621 def get_prefix(self, env, sources=[]):
624 prefix = prefix(env, sources)
625 return env.subst(prefix)
627 def set_suffix(self, suffix):
628 if not callable(suffix):
629 suffix = self.adjust_suffix(suffix)
632 def get_suffix(self, env, sources=[]):
635 suffix = suffix(env, sources)
636 return env.subst(suffix)
638 def set_src_suffix(self, src_suffix):
641 elif not SCons.Util.is_List(src_suffix):
642 src_suffix = [ src_suffix ]
643 adjust = lambda suf, s=self: \
644 callable(suf) and suf or s.adjust_suffix(suf)
645 self.src_suffix = map(adjust, src_suffix)
647 def get_src_suffix(self, env):
648 """Get the first src_suffix in the list of src_suffixes."""
649 ret = self.src_suffixes(env)
654 def add_emitter(self, suffix, emitter):
655 """Add a suffix-emitter mapping to this Builder.
657 This assumes that emitter has been initialized with an
658 appropriate dictionary type, and will throw a TypeError if
659 not, so the caller is responsible for knowing that this is an
660 appropriate method to call for the Builder in question.
662 self.emitter[suffix] = emitter
664 def add_src_builder(self, builder):
666 Add a new Builder to the list of src_builders.
668 This requires wiping out cached values so that the computed
669 lists of source suffixes get re-calculated.
672 self.src_builder.append(builder)
674 def _get_sdict(self, env):
676 Returns a dictionary mapping all of the source suffixes of all
677 src_builders of this Builder to the underlying Builder that
678 should be called first.
680 This dictionary is used for each target specified, so we save a
681 lot of extra computation by memoizing it for each construction
684 Note that this is re-computed each time, not cached, because there
685 might be changes to one of our source Builders (or one of their
686 source Builders, and so on, and so on...) that we can't "see."
688 The underlying methods we call cache their computed values,
689 though, so we hope repeatedly aggregating them into a dictionary
690 like this won't be too big a hit. We may need to look for a
691 better way to do this if performance data show this has turned
692 into a significant bottleneck.
695 for bld in self.get_src_builders(env):
696 for suf in bld.src_suffixes(env):
700 def src_builder_sources(self, env, source, overwarn={}):
701 sdict = self._get_sdict(env)
703 src_suffixes = self.src_suffixes(env)
705 lengths = list(set(map(len, src_suffixes)))
707 def match_src_suffix(name, src_suffixes=src_suffixes, lengths=lengths):
708 node_suffixes = map(lambda l, n=name: n[-l:], lengths)
709 for suf in src_suffixes:
710 if suf in node_suffixes:
715 for s in SCons.Util.flatten(source):
716 if SCons.Util.is_String(s):
717 match_suffix = match_src_suffix(env.subst(s))
718 if not match_suffix and not '.' in s:
719 src_suf = self.get_src_suffix(env)
720 s = self._adjustixes(s, None, src_suf)[0]
722 match_suffix = match_src_suffix(s.name)
725 bld = sdict[match_suffix]
729 tlist = bld._execute(env, None, [s], overwarn)
730 # If the subsidiary Builder returned more than one
731 # target, then filter out any sources that this
732 # Builder isn't capable of building.
734 mss = lambda t, m=match_src_suffix: m(t.name)
735 tlist = filter(mss, tlist)
740 source_factory = env.get_factory(self.source_factory)
742 return env.arg2nodes(result, source_factory)
744 def _get_src_builders_key(self, env):
747 memoizer_counters.append(SCons.Memoize.CountDict('get_src_builders', _get_src_builders_key))
749 def get_src_builders(self, env):
751 Returns the list of source Builders for this Builder.
753 This exists mainly to look up Builders referenced as
754 strings in the 'BUILDER' variable of the construction
755 environment and cache the result.
759 memo_dict = self._memo['get_src_builders']
762 self._memo['get_src_builders'] = memo_dict
765 return memo_dict[memo_key]
770 for bld in self.src_builder:
771 if SCons.Util.is_String(bld):
773 bld = env['BUILDERS'][bld]
778 memo_dict[memo_key] = builders
781 def _subst_src_suffixes_key(self, env):
784 memoizer_counters.append(SCons.Memoize.CountDict('subst_src_suffixes', _subst_src_suffixes_key))
786 def subst_src_suffixes(self, env):
788 The suffix list may contain construction variable expansions,
789 so we have to evaluate the individual strings. To avoid doing
790 this over and over, we memoize the results for each construction
795 memo_dict = self._memo['subst_src_suffixes']
798 self._memo['subst_src_suffixes'] = memo_dict
801 return memo_dict[memo_key]
804 suffixes = map(lambda x, s=self, e=env: e.subst(x), self.src_suffix)
805 memo_dict[memo_key] = suffixes
808 def src_suffixes(self, env):
810 Returns the list of source suffixes for all src_builders of this
813 This is essentially a recursive descent of the src_builder "tree."
814 (This value isn't cached because there may be changes in a
815 src_builder many levels deep that we can't see.)
818 suffixes = self.subst_src_suffixes(env)
821 for builder in self.get_src_builders(env):
822 for s in builder.src_suffixes(env):
823 if not sdict.has_key(s):
828 class CompositeBuilder(SCons.Util.Proxy):
829 """A Builder Proxy whose main purpose is to always have
830 a DictCmdGenerator as its action, and to provide access
831 to the DictCmdGenerator's add_action() method.
834 def __init__(self, builder, cmdgen):
835 if __debug__: logInstanceCreation(self, 'Builder.CompositeBuilder')
836 SCons.Util.Proxy.__init__(self, builder)
838 # cmdgen should always be an instance of DictCmdGenerator.
840 self.builder = builder
842 def add_action(self, suffix, action):
843 self.cmdgen.add_action(suffix, action)
844 self.set_src_suffix(self.cmdgen.src_suffixes())