blob: 0592bb492266682f5fb2d4e5e66ce2ac965b453e [file] [log] [blame]
Builder object subsystem.
A Builder object is a callable that encapsulates information about how
to execute actions to create a target Node (file) from source Nodes
(files), and how to create those dependencies for tracking.
The main entry point here is the Builder() factory method. This provides
a procedural interface that creates the right underlying Builder object
based on the keyword arguments supplied and the types of the arguments.
The goal is for this external interface to be simple enough that the
vast majority of users can create new Builders as necessary to support
building new types of files in their configurations, without having to
dive any deeper into this subsystem.
The base class here is BuilderBase. This is a concrete base class which
does, in fact, represent the Builder objects that we (or users) create.
There is also a proxy that looks like a Builder:
This proxies for a Builder with an action that is actually a
dictionary that knows how to map file suffixes to a specific
action. This is so that we can invoke different actions
(compilers, compile options) for different flavors of source
Builders and their proxies have the following public interface methods
used by other modules:
THE public interface. Calling a Builder object (with the
use of internal helper methods) sets up the target and source
dependencies, appropriate mapping to a specific action, and the
environment manipulation necessary for overridden construction
variable. This also takes care of warning about possible mistakes
in keyword arguments.
Adds an emitter for a specific file suffix, used by some Tool
modules to specify that (for example) a yacc invocation on a .y
can create a .h *and* a .c file.
Adds an action for a specific file suffix, heavily used by
Tool modules to add their specific action(s) for turning
a source file into an object file to the global static
and shared object file Builders.
There are the following methods for internal use within this module:
The internal method that handles the heavily lifting when a
Builder is called. This is used so that the __call__() methods
can set up warning about possible mistakes in keyword-argument
overrides, and *then* execute all of the steps necessary so that
the warnings only occur once.
Returns the Builder's name within a specific Environment,
primarily used to try to return helpful information in error
Miscellaneous stuff for handling the prefix and suffix
manipulation we use in turning source file names into target
file names.
# Copyright (c) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010 The SCons Foundation
# Permission is hereby granted, free of charge, to any person obtaining
# a copy of this software and associated documentation files (the
# "Software"), to deal in the Software without restriction, including
# without limitation the rights to use, copy, modify, merge, publish,
# distribute, sublicense, and/or sell copies of the Software, and to
# permit persons to whom the Software is furnished to do so, subject to
# the following conditions:
# The above copyright notice and this permission notice shall be included
# in all copies or substantial portions of the Software.
__revision__ = "src/engine/SCons/ 5134 2010/08/16 23:02:40 bdeegan"
import collections
import SCons.Action
from SCons.Debug import logInstanceCreation
from SCons.Errors import InternalError, UserError
import SCons.Executor
import SCons.Memoize
import SCons.Node
import SCons.Node.FS
import SCons.Util
import SCons.Warnings
class _Null(object):
_null = _Null
def match_splitext(path, suffixes = []):
if suffixes:
matchsuf = [S for S in suffixes if path[-len(S):] == S]
if matchsuf:
suf = max([(len(_f),_f) for _f in matchsuf])[1]
return [path[:-len(suf)], path[-len(suf):]]
return SCons.Util.splitext(path)
class DictCmdGenerator(SCons.Util.Selector):
"""This is a callable class that can be used as a
command generator function. It holds on to a dictionary
mapping file suffixes to Actions. It uses that dictionary
to return the proper action based on the file suffix of
the source file."""
def __init__(self, dict=None, source_ext_match=1):
SCons.Util.Selector.__init__(self, dict)
self.source_ext_match = source_ext_match
def src_suffixes(self):
return list(self.keys())
def add_action(self, suffix, action):
"""Add a suffix-action pair to the mapping.
self[suffix] = action
def __call__(self, target, source, env, for_signature):
if not source:
return []
if self.source_ext_match:
suffixes = self.src_suffixes()
ext = None
for src in map(str, source):
my_ext = match_splitext(src, suffixes)[1]
if ext and my_ext != ext:
raise UserError("While building `%s' from `%s': Cannot build multiple sources with different extensions: %s, %s"
% (repr(list(map(str, target))), src, ext, my_ext))
ext = my_ext
ext = match_splitext(str(source[0]), self.src_suffixes())[1]
if not ext:
#return ext
raise UserError("While building `%s': "
"Cannot deduce file extension from source files: %s"
% (repr(list(map(str, target))), repr(list(map(str, source)))))
ret = SCons.Util.Selector.__call__(self, env, source, ext)
except KeyError, e:
raise UserError("Ambiguous suffixes after environment substitution: %s == %s == %s" % (e.args[0], e.args[1], e.args[2]))
if ret is None:
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." % \
(repr(list(map(str, target))), repr(list(map(str, source))), ext, repr(list(self.keys()))))
return ret
class CallableSelector(SCons.Util.Selector):
"""A callable dictionary that will, in turn, call the value it
finds if it can."""
def __call__(self, env, source):
value = SCons.Util.Selector.__call__(self, env, source)
if callable(value):
value = value(env, source)
return value
class DictEmitter(SCons.Util.Selector):
"""A callable dictionary that maps file suffixes to emitters.
When called, it finds the right emitter in its dictionary for the
suffix of the first source file, and calls that emitter to get the
right lists of targets and sources to return. If there's no emitter
for the suffix in its dictionary, the original target and source are
def __call__(self, target, source, env):
emitter = SCons.Util.Selector.__call__(self, env, source)
if emitter:
target, source = emitter(target, source, env)
return (target, source)
class ListEmitter(collections.UserList):
"""A callable list of emitters that calls each in sequence,
returning the result.
def __call__(self, target, source, env):
for e in
target, source = e(target, source, env)
return (target, source)
# These are a common errors when calling a Builder;
# they are similar to the 'target' and 'source' keyword args to builders,
# so we issue warnings when we see them. The warnings can, of course,
# be disabled.
misleading_keywords = {
'targets' : 'target',
'sources' : 'source',
class OverrideWarner(collections.UserDict):
"""A class for warning about keyword arguments that we use as
overrides in a Builder call.
This class exists to handle the fact that a single Builder call
can actually invoke multiple builders. This class only emits the
warnings once, no matter how many Builders are invoked.
def __init__(self, dict):
collections.UserDict.__init__(self, dict)
if __debug__: logInstanceCreation(self, 'Builder.OverrideWarner')
self.already_warned = None
def warn(self):
if self.already_warned:
for k in self.keys():
if k in misleading_keywords:
alt = misleading_keywords[k]
msg = "Did you mean to use `%s' instead of `%s'?" % (alt, k)
SCons.Warnings.warn(SCons.Warnings.MisleadingKeywordsWarning, msg)
self.already_warned = 1
def Builder(**kw):
"""A factory for builder objects."""
composite = None
if 'generator' in kw:
if 'action' in kw:
raise UserError("You must not specify both an action and a generator.")
kw['action'] = SCons.Action.CommandGeneratorAction(kw['generator'], {})
del kw['generator']
elif 'action' in kw:
source_ext_match = kw.get('source_ext_match', 1)
if 'source_ext_match' in kw:
del kw['source_ext_match']
if SCons.Util.is_Dict(kw['action']):
composite = DictCmdGenerator(kw['action'], source_ext_match)
kw['action'] = SCons.Action.CommandGeneratorAction(composite, {})
kw['src_suffix'] = composite.src_suffixes()
kw['action'] = SCons.Action.Action(kw['action'])
if 'emitter' in kw:
emitter = kw['emitter']
if SCons.Util.is_String(emitter):
# This allows users to pass in an Environment
# variable reference (like "$FOO") as an emitter.
# We will look in that Environment variable for
# a callable to use as the actual emitter.
var = SCons.Util.get_environment_var(emitter)
if not var:
raise UserError("Supplied emitter '%s' does not appear to refer to an Environment variable" % emitter)
kw['emitter'] = EmitterProxy(var)
elif SCons.Util.is_Dict(emitter):
kw['emitter'] = DictEmitter(emitter)
elif SCons.Util.is_List(emitter):
kw['emitter'] = ListEmitter(emitter)
result = BuilderBase(**kw)
if not composite is None:
result = CompositeBuilder(result, composite)
return result
def _node_errors(builder, env, tlist, slist):
"""Validate that the lists of target and source nodes are
legal for this builder and environment. Raise errors or
issue warnings as appropriate.
# First, figure out if there are any errors in the way the targets
# were specified.
for t in tlist:
if t.side_effect:
raise UserError("Multiple ways to build the same target were specified for: %s" % t)
if t.has_explicit_builder():
if not t.env is None and not t.env is env:
action = t.builder.action
t_contents = action.get_contents(tlist, slist, t.env)
contents = action.get_contents(tlist, slist, env)
if t_contents == contents:
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))
SCons.Warnings.warn(SCons.Warnings.DuplicateEnvironmentWarning, msg)
msg = "Two environments with different actions were specified for the same target: %s" % t
raise UserError(msg)
if builder.multi:
if t.builder != builder:
msg = "Two different builders (%s and %s) were specified for the same target: %s" % (t.builder.get_name(env), builder.get_name(env), t)
raise UserError(msg)
# TODO(batch): list constructed each time!
if t.get_executor().get_all_targets() != tlist:
msg = "Two different target lists have a target in common: %s (from %s and from %s)" % (t, list(map(str, t.get_executor().get_all_targets())), list(map(str, tlist)))
raise UserError(msg)
elif t.sources != slist:
msg = "Multiple ways to build the same target were specified for: %s (from %s and from %s)" % (t, list(map(str, t.sources)), list(map(str, slist)))
raise UserError(msg)
if builder.single_source:
if len(slist) > 1:
raise UserError("More than one source given for single-source builder: targets=%s sources=%s" % (list(map(str,tlist)), list(map(str,slist))))
class EmitterProxy(object):
"""This is a callable class that can act as a
Builder emitter. It holds on to a string that
is a key into an Environment dictionary, and will
look there at actual build time to see if it holds
a callable. If so, we will call that as the actual
def __init__(self, var):
self.var = SCons.Util.to_String(var)
def __call__(self, target, source, env):
emitter = self.var
# Recursively substitute the variable.
# We can't use env.subst() because it deals only
# in strings. Maybe we should change that?
while SCons.Util.is_String(emitter) and emitter in env:
emitter = env[emitter]
if callable(emitter):
target, source = emitter(target, source, env)
elif SCons.Util.is_List(emitter):
for e in emitter:
target, source = e(target, source, env)
return (target, source)
def __cmp__(self, other):
return cmp(self.var, other.var)
class BuilderBase(object):
"""Base class for Builders, objects that create output
nodes (files) from input nodes (files).
if SCons.Memoize.use_memoizer:
__metaclass__ = SCons.Memoize.Memoized_Metaclass
memoizer_counters = []
def __init__(self, action = None,
prefix = '',
suffix = '',
src_suffix = '',
target_factory = None,
source_factory = None,
target_scanner = None,
source_scanner = None,
emitter = None,
multi = 0,
env = None,
single_source = 0,
name = None,
chdir = _null,
is_explicit = 1,
src_builder = None,
ensure_suffix = False,
if __debug__: logInstanceCreation(self, 'Builder.BuilderBase')
self._memo = {}
self.action = action
self.multi = multi
if SCons.Util.is_Dict(prefix):
prefix = CallableSelector(prefix)
self.prefix = prefix
if SCons.Util.is_Dict(suffix):
suffix = CallableSelector(suffix)
self.env = env
self.single_source = single_source
if 'overrides' in overrides:
"The \"overrides\" keyword to Builder() creation has been deprecated;\n" +\
"\tspecify the items as keyword arguments to the Builder() call instead.")
del overrides['overrides']
if 'scanner' in overrides:
"The \"scanner\" keyword to Builder() creation has been deprecated;\n"
"\tuse: source_scanner or target_scanner as appropriate.")
del overrides['scanner']
self.overrides = overrides
self.ensure_suffix = ensure_suffix
self.target_factory = target_factory
self.source_factory = source_factory
self.target_scanner = target_scanner
self.source_scanner = source_scanner
self.emitter = emitter
# Optional Builder name should only be used for Builders
# that don't get attached to construction environments.
if name: = name
self.executor_kw = {}
if not chdir is _null:
self.executor_kw['chdir'] = chdir
self.is_explicit = is_explicit
if src_builder is None:
src_builder = []
elif not SCons.Util.is_List(src_builder):
src_builder = [ src_builder ]
self.src_builder = src_builder
def __nonzero__(self):
raise InternalError("Do not test for the Node.builder attribute directly; use Node.has_builder() instead")
def get_name(self, env):
"""Attempts to get the name of the Builder.
Look at the BUILDERS variable of env, expecting it to be a
dictionary containing this Builder, and return the key of the
dictionary. If there's no key, then return a directly-configured
name (if there is one) or the name of the class (by default)."""
index = list(env['BUILDERS'].values()).index(self)
return list(env['BUILDERS'].keys())[index]
except (AttributeError, KeyError, TypeError, ValueError):
except AttributeError:
return str(self.__class__)
def __cmp__(self, other):
return cmp(self.__dict__, other.__dict__)
def splitext(self, path, env=None):
if not env:
env = self.env
if env:
suffixes = self.src_suffixes(env)
suffixes = []
return match_splitext(path, suffixes)
def _adjustixes(self, files, pre, suf, ensure_suffix=False):
if not files:
return []
result = []
if not SCons.Util.is_List(files):
files = [files]
for f in files:
if SCons.Util.is_String(f):
f = SCons.Util.adjustixes(f, pre, suf, ensure_suffix)
return result
def _create_nodes(self, env, target = None, source = None):
"""Create and return lists of target and source nodes.
src_suf = self.get_src_suffix(env)
target_factory = env.get_factory(self.target_factory)
source_factory = env.get_factory(self.source_factory)
source = self._adjustixes(source, None, src_suf)
slist = env.arg2nodes(source, source_factory)
pre = self.get_prefix(env, slist)
suf = self.get_suffix(env, slist)
if target is None:
t_from_s = slist[0].target_from_source
except AttributeError:
raise UserError("Do not know how to create a target from source `%s'" % slist[0])
except IndexError:
tlist = []
splitext = lambda S: self.splitext(S,env)
tlist = [ t_from_s(pre, suf, splitext) ]
target = self._adjustixes(target, pre, suf, self.ensure_suffix)
tlist = env.arg2nodes(target, target_factory, target=target, source=source)
if self.emitter:
# The emitter is going to do str(node), but because we're
# being called *from* a builder invocation, the new targets
# don't yet have a builder set on them and will look like
# source files. Fool the emitter's str() calls by setting
# up a temporary builder on the new targets.
new_targets = []
for t in tlist:
if not t.is_derived():
orig_tlist = tlist[:]
orig_slist = slist[:]
target, source = self.emitter(target=tlist, source=slist, env=env)
# Now delete the temporary builders that we attached to any
# new targets, so that _node_errors() doesn't do weird stuff
# to them because it thinks they already have builders.
for t in new_targets:
if t.builder is self:
# Only delete the temporary builder if the emitter
# didn't change it on us.
# Have to call arg2nodes yet again, since it is legal for
# emitters to spit out strings as well as Node instances.
tlist = env.arg2nodes(target, target_factory,
target=orig_tlist, source=orig_slist)
slist = env.arg2nodes(source, source_factory,
target=orig_tlist, source=orig_slist)
return tlist, slist
def _execute(self, env, target, source, overwarn={}, executor_kw={}):
# We now assume that target and source are lists or None.
if self.src_builder:
source = self.src_builder_sources(env, source, overwarn)
if self.single_source and len(source) > 1 and target is None:
result = []
if target is None: target = [None]*len(source)
for tgt, src in zip(target, source):
if not tgt is None: tgt = [tgt]
if not src is None: src = [src]
result.extend(self._execute(env, tgt, src, overwarn))
return SCons.Node.NodeList(result)
tlist, slist = self._create_nodes(env, target, source)
# Check for errors with the specified target/source lists.
_node_errors(self, env, tlist, slist)
# The targets are fine, so find or make the appropriate Executor to
# build this particular list of targets from this particular list of
# sources.
executor = None
key = None
if self.multi:
executor = tlist[0].get_executor(create = 0)
except (AttributeError, IndexError):
if executor is None:
if not self.action:
fmt = "Builder %s must have an action to build %s."
raise UserError(fmt % (self.get_name(env or self.env),
key = self.action.batch_key(env or self.env, tlist, slist)
if key:
executor = SCons.Executor.GetBatchExecutor(key)
except KeyError:
executor.add_batch(tlist, slist)
if executor is None:
executor = SCons.Executor.Executor(self.action, env, [],
tlist, slist, executor_kw)
if key:
SCons.Executor.AddBatchExecutor(key, executor)
# Now set up the relevant information in the target Nodes themselves.
for t in tlist:
t.cwd = env.fs.getcwd()
return SCons.Node.NodeList(tlist)
def __call__(self, env, target=None, source=None, chdir=_null, **kw):
# We now assume that target and source are lists or None.
# The caller (typically Environment.BuilderWrapper) is
# responsible for converting any scalar values to lists.
if chdir is _null:
ekw = self.executor_kw
ekw = self.executor_kw.copy()
ekw['chdir'] = chdir
if kw:
if 'srcdir' in kw:
def prependDirIfRelative(f, srcdir=kw['srcdir']):
import os.path
if SCons.Util.is_String(f) and not os.path.isabs(f):
f = os.path.join(srcdir, f)
return f
if not SCons.Util.is_List(source):
source = [source]
source = list(map(prependDirIfRelative, source))
del kw['srcdir']
if self.overrides:
env_kw = self.overrides.copy()
env_kw = kw
env_kw = self.overrides
env = env.Override(env_kw)
return self._execute(env, target, source, OverrideWarner(kw), ekw)
def adjust_suffix(self, suff):
if suff and not suff[0] in [ '.', '_', '$' ]:
return '.' + suff
return suff
def get_prefix(self, env, sources=[]):
prefix = self.prefix
if callable(prefix):
prefix = prefix(env, sources)
return env.subst(prefix)
def set_suffix(self, suffix):
if not callable(suffix):
suffix = self.adjust_suffix(suffix)
self.suffix = suffix
def get_suffix(self, env, sources=[]):
suffix = self.suffix
if callable(suffix):
suffix = suffix(env, sources)
return env.subst(suffix)
def set_src_suffix(self, src_suffix):
if not src_suffix:
src_suffix = []
elif not SCons.Util.is_List(src_suffix):
src_suffix = [ src_suffix ]
self.src_suffix = [callable(suf) and suf or self.adjust_suffix(suf) for suf in src_suffix]
def get_src_suffix(self, env):
"""Get the first src_suffix in the list of src_suffixes."""
ret = self.src_suffixes(env)
if not ret:
return ''
return ret[0]
def add_emitter(self, suffix, emitter):
"""Add a suffix-emitter mapping to this Builder.
This assumes that emitter has been initialized with an
appropriate dictionary type, and will throw a TypeError if
not, so the caller is responsible for knowing that this is an
appropriate method to call for the Builder in question.
self.emitter[suffix] = emitter
def add_src_builder(self, builder):
Add a new Builder to the list of src_builders.
This requires wiping out cached values so that the computed
lists of source suffixes get re-calculated.
self._memo = {}
def _get_sdict(self, env):
Returns a dictionary mapping all of the source suffixes of all
src_builders of this Builder to the underlying Builder that
should be called first.
This dictionary is used for each target specified, so we save a
lot of extra computation by memoizing it for each construction
Note that this is re-computed each time, not cached, because there
might be changes to one of our source Builders (or one of their
source Builders, and so on, and so on...) that we can't "see."
The underlying methods we call cache their computed values,
though, so we hope repeatedly aggregating them into a dictionary
like this won't be too big a hit. We may need to look for a
better way to do this if performance data show this has turned
into a significant bottleneck.
sdict = {}
for bld in self.get_src_builders(env):
for suf in bld.src_suffixes(env):
sdict[suf] = bld
return sdict
def src_builder_sources(self, env, source, overwarn={}):
sdict = self._get_sdict(env)
src_suffixes = self.src_suffixes(env)
lengths = list(set(map(len, src_suffixes)))
def match_src_suffix(name, src_suffixes=src_suffixes, lengths=lengths):
node_suffixes = [name[-l:] for l in lengths]
for suf in src_suffixes:
if suf in node_suffixes:
return suf
return None
result = []
for s in SCons.Util.flatten(source):
if SCons.Util.is_String(s):
match_suffix = match_src_suffix(env.subst(s))
if not match_suffix and not '.' in s:
src_suf = self.get_src_suffix(env)
s = self._adjustixes(s, None, src_suf)[0]
match_suffix = match_src_suffix(
if match_suffix:
bld = sdict[match_suffix]
except KeyError:
tlist = bld._execute(env, None, [s], overwarn)
# If the subsidiary Builder returned more than one
# target, then filter out any sources that this
# Builder isn't capable of building.
if len(tlist) > 1:
tlist = [t for t in tlist if match_src_suffix(]
source_factory = env.get_factory(self.source_factory)
return env.arg2nodes(result, source_factory)
def _get_src_builders_key(self, env):
return id(env)
memoizer_counters.append(SCons.Memoize.CountDict('get_src_builders', _get_src_builders_key))
def get_src_builders(self, env):
Returns the list of source Builders for this Builder.
This exists mainly to look up Builders referenced as
strings in the 'BUILDER' variable of the construction
environment and cache the result.
memo_key = id(env)
memo_dict = self._memo['get_src_builders']
except KeyError:
memo_dict = {}
self._memo['get_src_builders'] = memo_dict
return memo_dict[memo_key]
except KeyError:
builders = []
for bld in self.src_builder:
if SCons.Util.is_String(bld):
bld = env['BUILDERS'][bld]
except KeyError:
memo_dict[memo_key] = builders
return builders
def _subst_src_suffixes_key(self, env):
return id(env)
memoizer_counters.append(SCons.Memoize.CountDict('subst_src_suffixes', _subst_src_suffixes_key))
def subst_src_suffixes(self, env):
The suffix list may contain construction variable expansions,
so we have to evaluate the individual strings. To avoid doing
this over and over, we memoize the results for each construction
memo_key = id(env)
memo_dict = self._memo['subst_src_suffixes']
except KeyError:
memo_dict = {}
self._memo['subst_src_suffixes'] = memo_dict
return memo_dict[memo_key]
except KeyError:
suffixes = [env.subst(x) for x in self.src_suffix]
memo_dict[memo_key] = suffixes
return suffixes
def src_suffixes(self, env):
Returns the list of source suffixes for all src_builders of this
This is essentially a recursive descent of the src_builder "tree."
(This value isn't cached because there may be changes in a
src_builder many levels deep that we can't see.)
sdict = {}
suffixes = self.subst_src_suffixes(env)
for s in suffixes:
sdict[s] = 1
for builder in self.get_src_builders(env):
for s in builder.src_suffixes(env):
if s not in sdict:
sdict[s] = 1
return suffixes
class CompositeBuilder(SCons.Util.Proxy):
"""A Builder Proxy whose main purpose is to always have
a DictCmdGenerator as its action, and to provide access
to the DictCmdGenerator's add_action() method.
def __init__(self, builder, cmdgen):
if __debug__: logInstanceCreation(self, 'Builder.CompositeBuilder')
SCons.Util.Proxy.__init__(self, builder)
# cmdgen should always be an instance of DictCmdGenerator.
self.cmdgen = cmdgen
self.builder = builder
__call__ = SCons.Util.Delegate('__call__')
def add_action(self, suffix, action):
self.cmdgen.add_action(suffix, action)
def is_a_Builder(obj):
""""Returns True iff the specified obj is one of our Builder classes.
The test is complicated a bit by the fact that CompositeBuilder
is a proxy, not a subclass of BuilderBase.
return (isinstance(obj, BuilderBase)
or isinstance(obj, CompositeBuilder)
or callable(obj))
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