Source code for SCons.Node

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"""The Node package for the SCons software construction utility.

This is, in many ways, the heart of SCons.

A Node is where we encapsulate all of the dependency information about
any thing that SCons can build, or about any thing which SCons can use
to build some other thing.  The canonical "thing," of course, is a file,
but a Node can also represent something remote (like a web page) or
something completely abstract (like an Alias).

Each specific type of "thing" is specifically represented by a subclass
of the Node base class:  Node.FS.File for files, Node.Alias for aliases,
etc.  Dependency information is kept here in the base class, and
information specific to files/aliases/etc. is in the subclass.  The
goal, if we've done this correctly, is that any type of "thing" should
be able to depend on any other type of "thing."

"""

import collections
import copy
from itertools import chain, zip_longest

import SCons.Debug
import SCons.Executor
import SCons.Memoize
from SCons.compat import NoSlotsPyPy
from SCons.Debug import logInstanceCreation, Trace
from SCons.Util import hash_signature, is_List, UniqueList, render_tree

print_duplicate = 0

[docs]def classname(obj): return str(obj.__class__).split('.')[-1]
# Set to false if we're doing a dry run. There's more than one of these # little treats do_store_info = True # Node states # # These are in "priority" order, so that the maximum value for any # child/dependency of a node represents the state of that node if # it has no builder of its own. The canonical example is a file # system directory, which is only up to date if all of its children # were up to date. no_state = 0 pending = 1 executing = 2 up_to_date = 3 executed = 4 failed = 5 StateString = { 0 : "no_state", 1 : "pending", 2 : "executing", 3 : "up_to_date", 4 : "executed", 5 : "failed", } # controls whether implicit dependencies are cached: implicit_cache = 0 # controls whether implicit dep changes are ignored: implicit_deps_unchanged = 0 # controls whether the cached implicit deps are ignored: implicit_deps_changed = 0 # A variable that can be set to an interface-specific function be called # to annotate a Node with information about its creation.
[docs]def do_nothing_node(node): pass
Annotate = do_nothing_node # global set for recording all processed SContruct/SConscript nodes SConscriptNodes = set() # Gets set to 'True' if we're running in interactive mode. Is # currently used to release parts of a target's info during # clean builds and update runs (see release_target_info). interactive = False
[docs]def is_derived_none(node): raise NotImplementedError
[docs]def is_derived_node(node): """ Returns true if this node is derived (i.e. built). """ return node.has_builder() or node.side_effect
_is_derived_map = {0 : is_derived_none, 1 : is_derived_node}
[docs]def exists_none(node): raise NotImplementedError
[docs]def exists_always(node): return 1
[docs]def exists_base(node): return node.stat() is not None
[docs]def exists_entry(node): """Return if the Entry exists. Check the file system to see what we should turn into first. Assume a file if there's no directory.""" node.disambiguate() return _exists_map[node._func_exists](node)
[docs]def exists_file(node): # Duplicate from source path if we are set up to do this. if node.duplicate and not node.is_derived() and not node.linked: src = node.srcnode() if src is not node: # At this point, src is meant to be copied in a variant directory. src = src.rfile() if src.get_abspath() != node.get_abspath(): if src.exists(): node.do_duplicate(src) # Can't return 1 here because the duplication might # not actually occur if the -n option is being used. else: # The source file does not exist. Make sure no old # copy remains in the variant directory. if print_duplicate: print("dup: no src for %s, unlinking old variant copy" % node) if exists_base(node) or node.islink(): node.fs.unlink(node.get_internal_path()) # Return None explicitly because the Base.exists() call # above will have cached its value if the file existed. return None return exists_base(node)
_exists_map = {0 : exists_none, 1 : exists_always, 2 : exists_base, 3 : exists_entry, 4 : exists_file}
[docs]def rexists_none(node): raise NotImplementedError
[docs]def rexists_node(node): return node.exists()
[docs]def rexists_base(node): return node.rfile().exists()
_rexists_map = {0 : rexists_none, 1 : rexists_node, 2 : rexists_base}
[docs]def get_contents_none(node): raise NotImplementedError
[docs]def get_contents_entry(node): """Fetch the contents of the entry. Returns the exact binary contents of the file.""" try: node = node.disambiguate(must_exist=1) except SCons.Errors.UserError: # There was nothing on disk with which to disambiguate # this entry. Leave it as an Entry, but return a null # string so calls to get_contents() in emitters and the # like (e.g. in qt.py) don't have to disambiguate by hand # or catch the exception. return '' else: return _get_contents_map[node._func_get_contents](node)
[docs]def get_contents_dir(node): """Return content signatures and names of all our children separated by new-lines. Ensure that the nodes are sorted.""" contents = [] for n in sorted(node.children(), key=lambda t: t.name): contents.append('%s %s\n' % (n.get_csig(), n.name)) return ''.join(contents)
[docs]def get_contents_file(node): if not node.rexists(): return b'' fname = node.rfile().get_abspath() try: with open(fname, "rb") as fp: contents = fp.read() except EnvironmentError as e: if not e.filename: e.filename = fname raise return contents
_get_contents_map = {0 : get_contents_none, 1 : get_contents_entry, 2 : get_contents_dir, 3 : get_contents_file}
[docs]def target_from_source_none(node, prefix, suffix, splitext): raise NotImplementedError
[docs]def target_from_source_base(node, prefix, suffix, splitext): return node.dir.Entry(prefix + splitext(node.name)[0] + suffix)
_target_from_source_map = {0 : target_from_source_none, 1 : target_from_source_base} # # The new decider subsystem for Nodes # # We would set and overwrite the changed_since_last_build function # before, but for being able to use slots (less memory!) we now have # a dictionary of the different decider functions. Then in the Node # subclasses we simply store the index to the decider that should be # used by it. # # # First, the single decider functions #
[docs]def changed_since_last_build_node(node, target, prev_ni, repo_node=None): """ Must be overridden in a specific subclass to return True if this Node (a dependency) has changed since the last time it was used to build the specified target. prev_ni is this Node's state (for example, its file timestamp, length, maybe content signature) as of the last time the target was built. Note that this method is called through the dependency, not the target, because a dependency Node must be able to use its own logic to decide if it changed. For example, File Nodes need to obey if we're configured to use timestamps, but Python Value Nodes never use timestamps and always use the content. If this method were called through the target, then each Node's implementation of this method would have to have more complicated logic to handle all the different Node types on which it might depend. """ raise NotImplementedError
[docs]def changed_since_last_build_alias(node, target, prev_ni, repo_node=None): cur_csig = node.get_csig() try: return cur_csig != prev_ni.csig except AttributeError: return 1
[docs]def changed_since_last_build_entry(node, target, prev_ni, repo_node=None): node.disambiguate() return _decider_map[node.changed_since_last_build](node, target, prev_ni, repo_node)
[docs]def changed_since_last_build_state_changed(node, target, prev_ni, repo_node=None): return node.state != SCons.Node.up_to_date
[docs]def decide_source(node, target, prev_ni, repo_node=None): return target.get_build_env().decide_source(node, target, prev_ni, repo_node)
[docs]def decide_target(node, target, prev_ni, repo_node=None): return target.get_build_env().decide_target(node, target, prev_ni, repo_node)
[docs]def changed_since_last_build_python(node, target, prev_ni, repo_node=None): cur_csig = node.get_csig() try: return cur_csig != prev_ni.csig except AttributeError: return 1
# # Now, the mapping from indices to decider functions # _decider_map = {0 : changed_since_last_build_node, 1 : changed_since_last_build_alias, 2 : changed_since_last_build_entry, 3 : changed_since_last_build_state_changed, 4 : decide_source, 5 : decide_target, 6 : changed_since_last_build_python} do_store_info = True # # The new store_info subsystem for Nodes # # We would set and overwrite the store_info function # before, but for being able to use slots (less memory!) we now have # a dictionary of the different functions. Then in the Node # subclasses we simply store the index to the info method that should be # used by it. # # # First, the single info functions #
[docs]def store_info_pass(node): pass
[docs]def store_info_file(node): # Merge our build information into the already-stored entry. # This accommodates "chained builds" where a file that's a target # in one build (SConstruct file) is a source in a different build. # See test/chained-build.py for the use case. if do_store_info: node.dir.sconsign().store_info(node.name, node)
store_info_map = {0 : store_info_pass, 1 : store_info_file} # Classes for signature info for Nodes.
[docs]class NodeInfoBase: """ The generic base class for signature information for a Node. Node subclasses should subclass NodeInfoBase to provide their own logic for dealing with their own Node-specific signature information. """ __slots__ = ('__weakref__',) current_version_id = 2
[docs] def update(self, node): try: field_list = self.field_list except AttributeError: return for f in field_list: try: delattr(self, f) except AttributeError: pass try: func = getattr(node, 'get_' + f) except AttributeError: pass else: setattr(self, f, func())
[docs] def convert(self, node, val): pass
[docs] def merge(self, other): """ Merge the fields of another object into this object. Already existing information is overwritten by the other instance's data. WARNING: If a '__dict__' slot is added, it should be updated instead of replaced. """ state = other.__getstate__() self.__setstate__(state)
[docs] def format(self, field_list=None, names=0): if field_list is None: try: field_list = self.field_list except AttributeError: field_list = list(getattr(self, '__dict__', {}).keys()) for obj in type(self).mro(): for slot in getattr(obj, '__slots__', ()): if slot not in ('__weakref__', '__dict__'): field_list.append(slot) field_list.sort() fields = [] for field in field_list: try: f = getattr(self, field) except AttributeError: f = None f = str(f) if names: f = field + ': ' + f fields.append(f) return fields
def __getstate__(self): """ Return all fields that shall be pickled. Walk the slots in the class hierarchy and add those to the state dictionary. If a '__dict__' slot is available, copy all entries to the dictionary. Also include the version id, which is fixed for all instances of a class. """ state = getattr(self, '__dict__', {}).copy() for obj in type(self).mro(): for name in getattr(obj,'__slots__',()): if hasattr(self, name): state[name] = getattr(self, name) state['_version_id'] = self.current_version_id try: del state['__weakref__'] except KeyError: pass return state def __setstate__(self, state): """ Restore the attributes from a pickled state. The version is discarded. """ # TODO check or discard version del state['_version_id'] for key, value in state.items(): if key not in ('__weakref__',): setattr(self, key, value)
[docs]class BuildInfoBase: """ The generic base class for build information for a Node. This is what gets stored in a .sconsign file for each target file. It contains a NodeInfo instance for this node (signature information that's specific to the type of Node) and direct attributes for the generic build stuff we have to track: sources, explicit dependencies, implicit dependencies, and action information. """ __slots__ = ("bsourcesigs", "bdependsigs", "bimplicitsigs", "bactsig", "bsources", "bdepends", "bact", "bimplicit", "__weakref__") current_version_id = 2 def __init__(self): # Create an object attribute from the class attribute so it ends up # in the pickled data in the .sconsign file. self.bsourcesigs = [] self.bdependsigs = [] self.bimplicitsigs = [] self.bactsig = None
[docs] def merge(self, other): """ Merge the fields of another object into this object. Already existing information is overwritten by the other instance's data. WARNING: If a '__dict__' slot is added, it should be updated instead of replaced. """ state = other.__getstate__() self.__setstate__(state)
def __getstate__(self): """ Return all fields that shall be pickled. Walk the slots in the class hierarchy and add those to the state dictionary. If a '__dict__' slot is available, copy all entries to the dictionary. Also include the version id, which is fixed for all instances of a class. """ state = getattr(self, '__dict__', {}).copy() for obj in type(self).mro(): for name in getattr(obj,'__slots__',()): if hasattr(self, name): state[name] = getattr(self, name) state['_version_id'] = self.current_version_id try: del state['__weakref__'] except KeyError: pass return state def __setstate__(self, state): """ Restore the attributes from a pickled state. """ # TODO check or discard version del state['_version_id'] for key, value in state.items(): if key not in ('__weakref__',): setattr(self, key, value)
[docs]class Node(object, metaclass=NoSlotsPyPy): """The base Node class, for entities that we know how to build, or use to build other Nodes. """ __slots__ = ['sources', 'sources_set', 'target_peers', '_specific_sources', 'depends', 'depends_set', 'ignore', 'ignore_set', 'prerequisites', 'implicit', 'waiting_parents', 'waiting_s_e', 'ref_count', 'wkids', 'env', 'state', 'precious', 'noclean', 'nocache', 'cached', 'always_build', 'includes', 'attributes', 'side_effect', 'side_effects', 'linked', '_memo', 'executor', 'binfo', 'ninfo', 'builder', 'is_explicit', 'implicit_set', 'changed_since_last_build', 'store_info', 'pseudo', '_tags', '_func_is_derived', '_func_exists', '_func_rexists', '_func_get_contents', '_func_target_from_source']
[docs] class Attrs: __slots__ = ('shared', '__dict__')
def __init__(self): if SCons.Debug.track_instances: logInstanceCreation(self, 'Node.Node') # Note that we no longer explicitly initialize a self.builder # attribute to None here. That's because the self.builder # attribute may be created on-the-fly later by a subclass (the # canonical example being a builder to fetch a file from a # source code system like CVS or Subversion). # Each list of children that we maintain is accompanied by a # dictionary used to look up quickly whether a node is already # present in the list. Empirical tests showed that it was # fastest to maintain them as side-by-side Node attributes in # this way, instead of wrapping up each list+dictionary pair in # a class. (Of course, we could always still do that in the # future if we had a good reason to...). self.sources = [] # source files used to build node self.sources_set = set() self._specific_sources = False self.depends = [] # explicit dependencies (from Depends) self.depends_set = set() self.ignore = [] # dependencies to ignore self.ignore_set = set() self.prerequisites = None self.implicit = None # implicit (scanned) dependencies (None means not scanned yet) self.waiting_parents = set() self.waiting_s_e = set() self.ref_count = 0 self.wkids = None # Kids yet to walk, when it's an array self.env = None self.state = no_state self.precious = None self.pseudo = False self.noclean = 0 self.nocache = 0 self.cached = 0 # is this node pulled from cache? self.always_build = None self.includes = None self.attributes = self.Attrs() # Generic place to stick information about the Node. self.side_effect = 0 # true iff this node is a side effect self.side_effects = [] # the side effects of building this target self.linked = 0 # is this node linked to the variant directory? self.changed_since_last_build = 0 self.store_info = 0 self._tags = None self._func_is_derived = 1 self._func_exists = 1 self._func_rexists = 1 self._func_get_contents = 0 self._func_target_from_source = 0 self.ninfo = None self.clear_memoized_values() # Let the interface in which the build engine is embedded # annotate this Node with its own info (like a description of # what line in what file created the node, for example). Annotate(self)
[docs] def disambiguate(self, must_exist=None): return self
[docs] def get_suffix(self): return ''
[docs] @SCons.Memoize.CountMethodCall def get_build_env(self): """Fetch the appropriate Environment to build this node. """ try: return self._memo['get_build_env'] except KeyError: pass result = self.get_executor().get_build_env() self._memo['get_build_env'] = result return result
[docs] def get_build_scanner_path(self, scanner): """Fetch the appropriate scanner path for this node.""" return self.get_executor().get_build_scanner_path(scanner)
[docs] def set_executor(self, executor): """Set the action executor for this node.""" self.executor = executor
[docs] def get_executor(self, create=1): """Fetch the action executor for this node. Create one if there isn't already one, and requested to do so.""" try: executor = self.executor except AttributeError: if not create: raise try: act = self.builder.action except AttributeError: executor = SCons.Executor.Null(targets=[self]) else: executor = SCons.Executor.Executor(act, self.env or self.builder.env, [self.builder.overrides], [self], self.sources) self.executor = executor return executor
[docs] def executor_cleanup(self): """Let the executor clean up any cached information.""" try: executor = self.get_executor(create=None) except AttributeError: pass else: if executor is not None: executor.cleanup()
[docs] def reset_executor(self): """Remove cached executor; forces recompute when needed.""" try: delattr(self, 'executor') except AttributeError: pass
[docs] def push_to_cache(self): """Try to push a node into a cache """ pass
[docs] def retrieve_from_cache(self): """Try to retrieve the node's content from a cache This method is called from multiple threads in a parallel build, so only do thread safe stuff here. Do thread unsafe stuff in built(). Returns true if the node was successfully retrieved. """ return 0
# # Taskmaster interface subsystem #
[docs] def make_ready(self): """Get a Node ready for evaluation. This is called before the Taskmaster decides if the Node is up-to-date or not. Overriding this method allows for a Node subclass to be disambiguated if necessary, or for an implicit source builder to be attached. """ pass
[docs] def prepare(self): """Prepare for this Node to be built. This is called after the Taskmaster has decided that the Node is out-of-date and must be rebuilt, but before actually calling the method to build the Node. This default implementation checks that explicit or implicit dependencies either exist or are derived, and initializes the BuildInfo structure that will hold the information about how this node is, uh, built. (The existence of source files is checked separately by the Executor, which aggregates checks for all of the targets built by a specific action.) Overriding this method allows for for a Node subclass to remove the underlying file from the file system. Note that subclass methods should call this base class method to get the child check and the BuildInfo structure. """ if self.depends is not None: for d in self.depends: if d.missing(): msg = "Explicit dependency `%s' not found, needed by target `%s'." raise SCons.Errors.StopError(msg % (d, self)) if self.implicit is not None: for i in self.implicit: if i.missing(): msg = "Implicit dependency `%s' not found, needed by target `%s'." raise SCons.Errors.StopError(msg % (i, self)) self.binfo = self.get_binfo()
[docs] def build(self, **kw): """Actually build the node. This is called by the Taskmaster after it's decided that the Node is out-of-date and must be rebuilt, and after the prepare() method has gotten everything, uh, prepared. This method is called from multiple threads in a parallel build, so only do thread safe stuff here. Do thread unsafe stuff in built(). """ try: self.get_executor()(self, **kw) except SCons.Errors.BuildError as e: e.node = self raise
[docs] def built(self): """Called just after this node is successfully built.""" # Clear the implicit dependency caches of any Nodes # waiting for this Node to be built. for parent in self.waiting_parents: parent.implicit = None # Handle issue where builder emits more than one target and # the source file for the builder is generated. # in that case only the first target was getting it's .implicit # cleared when the source file is built (second scan). # leaving only partial implicits from scan before source file is generated # typically the compiler only. Then scanned files are appended # This is persisted to sconsign and rebuild causes false rebuilds # because the ordering of the implicit list then changes to what it # should have been. # This is at least the following bugs # https://github.com/SCons/scons/issues/2811 # https://jira.mongodb.org/browse/SERVER-33111 try: for peer in parent.target_peers: peer.implicit = None except AttributeError: pass self.clear() if self.pseudo: if self.exists(): raise SCons.Errors.UserError("Pseudo target " + str(self) + " must not exist") else: if not self.exists() and do_store_info: SCons.Warnings.warn(SCons.Warnings.TargetNotBuiltWarning, "Cannot find target " + str(self) + " after building") self.ninfo.update(self)
[docs] def visited(self): """Called just after this node has been visited (with or without a build).""" try: binfo = self.binfo except AttributeError: # Apparently this node doesn't need build info, so # don't bother calculating or storing it. pass else: self.ninfo.update(self) SCons.Node.store_info_map[self.store_info](self)
[docs] def release_target_info(self): """Called just after this node has been marked up-to-date or was built completely. This is where we try to release as many target node infos as possible for clean builds and update runs, in order to minimize the overall memory consumption. By purging attributes that aren't needed any longer after a Node (=File) got built, we don't have to care that much how many KBytes a Node actually requires...as long as we free the memory shortly afterwards. @see: built() and File.release_target_info() """ pass
[docs] def add_to_waiting_s_e(self, node): self.waiting_s_e.add(node)
[docs] def add_to_waiting_parents(self, node): """ Returns the number of nodes added to our waiting parents list: 1 if we add a unique waiting parent, 0 if not. (Note that the returned values are intended to be used to increment a reference count, so don't think you can "clean up" this function by using True and False instead...) """ wp = self.waiting_parents if node in wp: return 0 wp.add(node) return 1
[docs] def postprocess(self): """Clean up anything we don't need to hang onto after we've been built.""" self.executor_cleanup() self.waiting_parents = set()
[docs] def clear(self): """Completely clear a Node of all its cached state (so that it can be re-evaluated by interfaces that do continuous integration builds). """ # The del_binfo() call here isn't necessary for normal execution, # but is for interactive mode, where we might rebuild the same # target and need to start from scratch. self.del_binfo() self.clear_memoized_values() self.ninfo = self.new_ninfo() self.executor_cleanup() for attr in ['cachedir_csig', 'cachesig', 'contentsig']: try: delattr(self, attr) except AttributeError: pass self.cached = 0 self.includes = None
[docs] def clear_memoized_values(self): self._memo = {}
[docs] def builder_set(self, builder): self.builder = builder try: del self.executor except AttributeError: pass
[docs] def has_builder(self): """Return whether this Node has a builder or not. In Boolean tests, this turns out to be a *lot* more efficient than simply examining the builder attribute directly ("if node.builder: ..."). When the builder attribute is examined directly, it ends up calling __getattr__ for both the __len__ and __bool__ attributes on instances of our Builder Proxy class(es), generating a bazillion extra calls and slowing things down immensely. """ try: b = self.builder except AttributeError: # There was no explicit builder for this Node, so initialize # the self.builder attribute to None now. b = self.builder = None return b is not None
[docs] def set_explicit(self, is_explicit): self.is_explicit = is_explicit
[docs] def has_explicit_builder(self): """Return whether this Node has an explicit builder This allows an internal Builder created by SCons to be marked non-explicit, so that it can be overridden by an explicit builder that the user supplies (the canonical example being directories).""" try: return self.is_explicit except AttributeError: self.is_explicit = None return self.is_explicit
[docs] def get_builder(self, default_builder=None): """Return the set builder, or a specified default value""" try: return self.builder except AttributeError: return default_builder
multiple_side_effect_has_builder = has_builder
[docs] def is_derived(self): """ Returns true if this node is derived (i.e. built). This should return true only for nodes whose path should be in the variant directory when duplicate=0 and should contribute their build signatures when they are used as source files to other derived files. For example: source with source builders are not derived in this sense, and hence should not return true. """ return _is_derived_map[self._func_is_derived](self)
[docs] def is_sconscript(self): """ Returns true if this node is an sconscript """ return self in SConscriptNodes
[docs] def is_conftest(self): """ Returns true if this node is an conftest node""" try: self.attributes.conftest_node except AttributeError: return False return True
[docs] def check_attributes(self, name): """ Simple API to check if the node.attributes for name has been set""" return getattr(getattr(self, "attributes", None), name, None)
[docs] def alter_targets(self): """Return a list of alternate targets for this Node. """ return [], None
[docs] def get_found_includes(self, env, scanner, path): """Return the scanned include lines (implicit dependencies) found in this node. The default is no implicit dependencies. We expect this method to be overridden by any subclass that can be scanned for implicit dependencies. """ return []
[docs] def get_implicit_deps(self, env, initial_scanner, path_func, kw = {}): """Return a list of implicit dependencies for this node. This method exists to handle recursive invocation of the scanner on the implicit dependencies returned by the scanner, if the scanner's recursive flag says that we should. """ nodes = [self] seen = set(nodes) dependencies = [] path_memo = {} root_node_scanner = self._get_scanner(env, initial_scanner, None, kw) while nodes: node = nodes.pop(0) scanner = node._get_scanner(env, initial_scanner, root_node_scanner, kw) if not scanner: continue try: path = path_memo[scanner] except KeyError: path = path_func(scanner) path_memo[scanner] = path included_deps = [x for x in node.get_found_includes(env, scanner, path) if x not in seen] if included_deps: dependencies.extend(included_deps) seen.update(included_deps) nodes.extend(scanner.recurse_nodes(included_deps)) return dependencies
[docs] def _get_scanner(self, env, initial_scanner, root_node_scanner, kw): if initial_scanner: # handle explicit scanner case scanner = initial_scanner.select(self) else: # handle implicit scanner case scanner = self.get_env_scanner(env, kw) if scanner: scanner = scanner.select(self) if not scanner: # no scanner could be found for the given node's scanner key; # thus, make an attempt at using a default. scanner = root_node_scanner return scanner
[docs] def get_env_scanner(self, env, kw={}): return env.get_scanner(self.scanner_key())
[docs] def get_target_scanner(self): return self.builder.target_scanner
[docs] def get_source_scanner(self, node): """Fetch the source scanner for the specified node NOTE: "self" is the target being built, "node" is the source file for which we want to fetch the scanner. Implies self.has_builder() is true; again, expect to only be called from locations where this is already verified. This function may be called very often; it attempts to cache the scanner found to improve performance. """ scanner = None try: scanner = self.builder.source_scanner except AttributeError: pass if not scanner: # The builder didn't have an explicit scanner, so go look up # a scanner from env['SCANNERS'] based on the node's scanner # key (usually the file extension). scanner = self.get_env_scanner(self.get_build_env()) if scanner: scanner = scanner.select(node) return scanner
[docs] def add_to_implicit(self, deps): if not hasattr(self, 'implicit') or self.implicit is None: self.implicit = [] self.implicit_set = set() self._children_reset() self._add_child(self.implicit, self.implicit_set, deps)
[docs] def scan(self): """Scan this node's dependents for implicit dependencies.""" # Don't bother scanning non-derived files, because we don't # care what their dependencies are. # Don't scan again, if we already have scanned. if self.implicit is not None: return self.implicit = [] self.implicit_set = set() self._children_reset() if not self.has_builder(): return build_env = self.get_build_env() executor = self.get_executor() # Here's where we implement --implicit-cache. if implicit_cache and not implicit_deps_changed: implicit = self.get_stored_implicit() if implicit is not None: # We now add the implicit dependencies returned from the # stored .sconsign entry to have already been converted # to Nodes for us. (We used to run them through a # source_factory function here.) # Update all of the targets with them. This # essentially short-circuits an N*M scan of the # sources for each individual target, which is a hell # of a lot more efficient. for tgt in executor.get_all_targets(): tgt.add_to_implicit(implicit) if implicit_deps_unchanged or self.is_up_to_date(): return # one of this node's sources has changed, # so we must recalculate the implicit deps for all targets for tgt in executor.get_all_targets(): tgt.implicit = [] tgt.implicit_set = set() # Have the executor scan the sources. executor.scan_sources(self.builder.source_scanner) # If there's a target scanner, have the executor scan the target # node itself and associated targets that might be built. scanner = self.get_target_scanner() if scanner: executor.scan_targets(scanner)
[docs] def scanner_key(self): return None
[docs] def select_scanner(self, scanner): """Selects a scanner for this Node. This is a separate method so it can be overridden by Node subclasses (specifically, Node.FS.Dir) that *must* use their own Scanner and don't select one the Scanner.Selector that's configured for the target. """ return scanner.select(self)
[docs] def env_set(self, env, safe=0): if safe and self.env: return self.env = env
# # SIGNATURE SUBSYSTEM # NodeInfo = NodeInfoBase BuildInfo = BuildInfoBase
[docs] def new_ninfo(self): ninfo = self.NodeInfo() return ninfo
[docs] def get_ninfo(self): if self.ninfo is not None: return self.ninfo self.ninfo = self.new_ninfo() return self.ninfo
[docs] def new_binfo(self): binfo = self.BuildInfo() return binfo
[docs] def get_binfo(self): """ Fetch a node's build information. node - the node whose sources will be collected cache - alternate node to use for the signature cache returns - the build signature This no longer handles the recursive descent of the node's children's signatures. We expect that they're already built and updated by someone else, if that's what's wanted. """ try: return self.binfo except AttributeError: pass binfo = self.new_binfo() self.binfo = binfo executor = self.get_executor() ignore_set = self.ignore_set if self.has_builder(): binfo.bact = str(executor) binfo.bactsig = hash_signature(executor.get_contents()) if self._specific_sources: sources = [s for s in self.sources if s not in ignore_set] else: sources = executor.get_unignored_sources(self, self.ignore) seen = set() binfo.bsources = [s for s in sources if s not in seen and not seen.add(s)] binfo.bsourcesigs = [s.get_ninfo() for s in binfo.bsources] binfo.bdepends = [d for d in self.depends if d not in ignore_set] binfo.bdependsigs = [d.get_ninfo() for d in self.depends] # Because self.implicit is initialized to None (and not empty list []) # we have to handle this case if not self.implicit: binfo.bimplicit = [] binfo.bimplicitsigs = [] else: binfo.bimplicit = [i for i in self.implicit if i not in ignore_set] binfo.bimplicitsigs = [i.get_ninfo() for i in binfo.bimplicit] return binfo
[docs] def del_binfo(self): """Delete the build info from this node.""" try: delattr(self, 'binfo') except AttributeError: pass
[docs] def get_csig(self): try: return self.ninfo.csig except AttributeError: ninfo = self.get_ninfo() ninfo.csig = hash_signature(self.get_contents()) return self.ninfo.csig
[docs] def get_cachedir_csig(self): return self.get_csig()
[docs] def get_stored_info(self): return None
[docs] def get_stored_implicit(self): """Fetch the stored implicit dependencies""" return None
# # #
[docs] def set_precious(self, precious = 1): """Set the Node's precious value.""" self.precious = precious
[docs] def set_pseudo(self, pseudo = True): """Set the Node's precious value.""" self.pseudo = pseudo
[docs] def set_noclean(self, noclean = 1): """Set the Node's noclean value.""" # Make sure noclean is an integer so the --debug=stree # output in Util.py can use it as an index. self.noclean = noclean and 1 or 0
[docs] def set_nocache(self, nocache = 1): """Set the Node's nocache value.""" # Make sure nocache is an integer so the --debug=stree # output in Util.py can use it as an index. self.nocache = nocache and 1 or 0
[docs] def set_always_build(self, always_build = 1): """Set the Node's always_build value.""" self.always_build = always_build
[docs] def exists(self): """Does this node exists?""" return _exists_map[self._func_exists](self)
[docs] def rexists(self): """Does this node exist locally or in a repository?""" # There are no repositories by default: return _rexists_map[self._func_rexists](self)
[docs] def get_contents(self): """Fetch the contents of the entry.""" return _get_contents_map[self._func_get_contents](self)
[docs] def missing(self): return not self.is_derived() and \ not self.linked and \ not self.rexists()
[docs] def remove(self): """Remove this Node: no-op by default.""" return None
[docs] def add_dependency(self, depend): """Adds dependencies.""" try: self._add_child(self.depends, self.depends_set, depend) except TypeError as e: e = e.args[0] if is_List(e): s = list(map(str, e)) else: s = str(e) 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)))
[docs] def add_prerequisite(self, prerequisite): """Adds prerequisites""" if self.prerequisites is None: self.prerequisites = UniqueList() self.prerequisites.extend(prerequisite) self._children_reset()
[docs] def add_ignore(self, depend): """Adds dependencies to ignore.""" try: self._add_child(self.ignore, self.ignore_set, depend) except TypeError as e: e = e.args[0] if is_List(e): s = list(map(str, e)) else: s = str(e) 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)))
[docs] def add_source(self, source): """Adds sources.""" if self._specific_sources: return try: self._add_child(self.sources, self.sources_set, source) except TypeError as e: e = e.args[0] if is_List(e): s = list(map(str, e)) else: s = str(e) 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)))
[docs] def _add_child(self, collection, set, child): """Adds 'child' to 'collection', first checking 'set' to see if it's already present.""" added = None for c in child: if c not in set: set.add(c) collection.append(c) added = 1 if added: self._children_reset()
[docs] def set_specific_source(self, source): self.add_source(source) self._specific_sources = True
[docs] def add_wkid(self, wkid): """Add a node to the list of kids waiting to be evaluated""" if self.wkids is not None: self.wkids.append(wkid)
[docs] def _children_reset(self): self.clear_memoized_values() # We need to let the Executor clear out any calculated # build info that it's cached so we can re-calculate it. self.executor_cleanup()
[docs] @SCons.Memoize.CountMethodCall def _children_get(self): try: return self._memo['_children_get'] except KeyError: pass # The return list may contain duplicate Nodes, especially in # source trees where there are a lot of repeated #includes # of a tangle of .h files. Profiling shows, however, that # eliminating the duplicates with a brute-force approach that # preserves the order (that is, something like: # # u = [] # for n in list: # if n not in u: # u.append(n)" # # takes more cycles than just letting the underlying methods # hand back cached values if a Node's information is requested # multiple times. (Other methods of removing duplicates, like # using dictionary keys, lose the order, and the only ordered # dictionary patterns I found all ended up using "not in" # internally anyway...) if self.ignore_set: iter = chain.from_iterable([_f for _f in [self.sources, self.depends, self.implicit] if _f]) children = [] for i in iter: if i not in self.ignore_set: children.append(i) else: children = self.all_children(scan=0) self._memo['_children_get'] = children return children
[docs] def all_children(self, scan=1): """Return a list of all the node's direct children.""" if scan: self.scan() # The return list may contain duplicate Nodes, especially in # source trees where there are a lot of repeated #includes # of a tangle of .h files. Profiling shows, however, that # eliminating the duplicates with a brute-force approach that # preserves the order (that is, something like: # # u = [] # for n in list: # if n not in u: # u.append(n)" # # takes more cycles than just letting the underlying methods # hand back cached values if a Node's information is requested # multiple times. (Other methods of removing duplicates, like # using dictionary keys, lose the order, and the only ordered # dictionary patterns I found all ended up using "not in" # internally anyway...) return list(chain.from_iterable([_f for _f in [self.sources, self.depends, self.implicit] if _f]))
[docs] def children(self, scan=1): """Return a list of the node's direct children, minus those that are ignored by this node.""" if scan: self.scan() return self._children_get()
[docs] def set_state(self, state): self.state = state
[docs] def get_state(self): return self.state
[docs] def get_env(self): env = self.env if not env: import SCons.Defaults env = SCons.Defaults.DefaultEnvironment() return env
[docs] def Decider(self, function): foundkey = None for k, v in _decider_map.items(): if v == function: foundkey = k break if not foundkey: foundkey = len(_decider_map) _decider_map[foundkey] = function self.changed_since_last_build = foundkey
[docs] def Tag(self, key, value): """ Add a user-defined tag. """ if not self._tags: self._tags = {} self._tags[key] = value
[docs] def GetTag(self, key): """ Return a user-defined tag. """ if not self._tags: return None return self._tags.get(key, None)
[docs] def changed(self, node=None, allowcache=False): """ Returns if the node is up-to-date with respect to the BuildInfo stored last time it was built. The default behavior is to compare it against our own previously stored BuildInfo, but the stored BuildInfo from another Node (typically one in a Repository) can be used instead. Note that we now *always* check every dependency. We used to short-circuit the check by returning as soon as we detected any difference, but we now rely on checking every dependency to make sure that any necessary Node information (for example, the content signature of an #included .h file) is updated. The allowcache option was added for supporting the early release of the executor/builder structures, right after a File target was built. When set to true, the return value of this changed method gets cached for File nodes. Like this, the executor isn't needed any longer for subsequent calls to changed(). @see: FS.File.changed(), FS.File.release_target_info() """ t = 0 if t: Trace('changed(%s [%s], %s)' % (self, classname(self), node)) if node is None: node = self result = False bi = node.get_stored_info().binfo then = bi.bsourcesigs + bi.bdependsigs + bi.bimplicitsigs children = self.children() diff = len(children) - len(then) if diff: # The old and new dependency lists are different lengths. # This always indicates that the Node must be rebuilt. # We also extend the old dependency list with enough None # entries to equal the new dependency list, for the benefit # of the loop below that updates node information. then.extend([None] * diff) if t: Trace(': old %s new %s' % (len(then), len(children))) result = True for child, prev_ni in zip(children, then): if _decider_map[child.changed_since_last_build](child, self, prev_ni, node): if t: Trace(': %s changed' % child) result = True if self.has_builder(): contents = self.get_executor().get_contents() newsig = hash_signature(contents) if bi.bactsig != newsig: if t: Trace(': bactsig %s != newsig %s' % (bi.bactsig, newsig)) result = True if not result: if t: Trace(': up to date') if t: Trace('\n') return result
[docs] def is_up_to_date(self): """Default check for whether the Node is current: unknown Node subtypes are always out of date, so they will always get built.""" return None
[docs] def children_are_up_to_date(self): """Alternate check for whether the Node is current: If all of our children were up-to-date, then this Node was up-to-date, too. The SCons.Node.Alias and SCons.Node.Python.Value subclasses rebind their current() method to this method.""" # Allow the children to calculate their signatures. self.binfo = self.get_binfo() if self.always_build: return None state = 0 for kid in self.children(None): s = kid.get_state() if s and (not state or s > state): state = s return (state == 0 or state == SCons.Node.up_to_date)
[docs] def is_literal(self): """Always pass the string representation of a Node to the command interpreter literally.""" return 1
[docs] def render_include_tree(self): """ Return a text representation, suitable for displaying to the user, of the include tree for the sources of this node. """ if self.is_derived(): env = self.get_build_env() if env: for s in self.sources: scanner = self.get_source_scanner(s) if scanner: path = self.get_build_scanner_path(scanner) else: path = None def f(node, env=env, scanner=scanner, path=path): return node.get_found_includes(env, scanner, path) return render_tree(s, f, 1) else: return None
[docs] def get_abspath(self): """ Return an absolute path to the Node. This will return simply str(Node) by default, but for Node types that have a concept of relative path, this might return something different. """ return str(self)
[docs] def for_signature(self): """ Return a string representation of the Node that will always be the same for this particular Node, no matter what. This is by contrast to the __str__() method, which might, for instance, return a relative path for a file Node. The purpose of this method is to generate a value to be used in signature calculation for the command line used to build a target, and we use this method instead of str() to avoid unnecessary rebuilds. This method does not need to return something that would actually work in a command line; it can return any kind of nonsense, so long as it does not change. """ return str(self)
[docs] def get_string(self, for_signature): """This is a convenience function designed primarily to be used in command generators (i.e., CommandGeneratorActions or Environment variables that are callable), which are called with a for_signature argument that is nonzero if the command generator is being called to generate a signature for the command line, which determines if we should rebuild or not. Such command generators should use this method in preference to str(Node) when converting a Node to a string, passing in the for_signature parameter, such that we will call Node.for_signature() or str(Node) properly, depending on whether we are calculating a signature or actually constructing a command line.""" if for_signature: return self.for_signature() return str(self)
[docs] def get_subst_proxy(self): """ This method is expected to return an object that will function exactly like this Node, except that it implements any additional special features that we would like to be in effect for Environment variable substitution. The principle use is that some Nodes would like to implement a __getattr__() method, but putting that in the Node type itself has a tendency to kill performance. We instead put it in a proxy and return it from this method. It is legal for this method to return self if no new functionality is needed for Environment substitution. """ return self
[docs] def explain(self): if not self.exists(): return "building `%s' because it doesn't exist\n" % self if self.always_build: return "rebuilding `%s' because AlwaysBuild() is specified\n" % self old = self.get_stored_info() if old is None: return None old = old.binfo old.prepare_dependencies() try: old_bkids = old.bsources + old.bdepends + old.bimplicit old_bkidsigs = old.bsourcesigs + old.bdependsigs + old.bimplicitsigs except AttributeError: return "Cannot explain why `%s' is being rebuilt: No previous build information found\n" % self new = self.get_binfo() new_bkids = new.bsources + new.bdepends + new.bimplicit new_bkidsigs = new.bsourcesigs + new.bdependsigs + new.bimplicitsigs osig = dict(list(zip(old_bkids, old_bkidsigs))) nsig = dict(list(zip(new_bkids, new_bkidsigs))) # The sources and dependencies we'll want to report are all stored # as relative paths to this target's directory, but we want to # report them relative to the top-level SConstruct directory, # so we only print them after running them through this lambda # to turn them into the right relative Node and then return # its string. def stringify( s, E=self.dir.Entry): if hasattr( s, 'dir' ) : return str(E(s)) return str(s) lines = [] removed = [x for x in old_bkids if x not in new_bkids] if removed: removed = [stringify(r) for r in removed] fmt = "`%s' is no longer a dependency\n" lines.extend([fmt % s for s in removed]) for k in new_bkids: if k not in old_bkids: lines.append("`%s' is a new dependency\n" % stringify(k)) else: changed = _decider_map[k.changed_since_last_build](k, self, osig[k]) if changed: lines.append("`%s' changed\n" % stringify(k)) if len(lines) == 0 and old_bkids != new_bkids: lines.append("the dependency order changed:\n") lines.append("->Sources\n") for (o,n) in zip_longest(old.bsources, new.bsources, fillvalue=None): lines.append("Old:%s\tNew:%s\n"%(o,n)) lines.append("->Depends\n") for (o,n) in zip_longest(old.bdepends, new.bdepends, fillvalue=None): lines.append("Old:%s\tNew:%s\n"%(o,n)) lines.append("->Implicit\n") for (o,n) in zip_longest(old.bimplicit, new.bimplicit, fillvalue=None): lines.append("Old:%s\tNew:%s\n"%(o,n)) if len(lines) == 0: def fmt_with_title(title, strlines): lines = strlines.split('\n') sep = '\n' + ' '*(15 + len(title)) return ' '*15 + title + sep.join(lines) + '\n' if old.bactsig != new.bactsig: if old.bact == new.bact: lines.append("the contents of the build action changed\n" + fmt_with_title('action: ', new.bact)) # lines.append("the contents of the build action changed [%s] [%s]\n"%(old.bactsig,new.bactsig) + # fmt_with_title('action: ', new.bact)) else: lines.append("the build action changed:\n" + fmt_with_title('old: ', old.bact) + fmt_with_title('new: ', new.bact)) if len(lines) == 0: return "rebuilding `%s' for unknown reasons\n" % self preamble = "rebuilding `%s' because" % self if len(lines) == 1: return "%s %s" % (preamble, lines[0]) else: lines = ["%s:\n" % preamble] + lines return ( ' '*11).join(lines)
[docs]class NodeList(collections.UserList): def __str__(self): return str(list(map(str, self.data)))
[docs]def get_children(node, parent): return node.children()
[docs]def ignore_cycle(node, stack): pass
[docs]def do_nothing(node, parent): pass
[docs]class Walker: """An iterator for walking a Node tree. This is depth-first, children are visited before the parent. The Walker object can be initialized with any node, and returns the next node on the descent with each get_next() call. get the children of a node instead of calling 'children'. 'cycle_func' is an optional function that will be called when a cycle is detected. This class does not get caught in node cycles caused, for example, by C header file include loops. """ def __init__(self, node, kids_func=get_children, cycle_func=ignore_cycle, eval_func=do_nothing): self.kids_func = kids_func self.cycle_func = cycle_func self.eval_func = eval_func node.wkids = copy.copy(kids_func(node, None)) self.stack = [node] self.history = {} # used to efficiently detect and avoid cycles self.history[node] = None
[docs] def get_next(self): """Return the next node for this walk of the tree. This function is intentionally iterative, not recursive, to sidestep any issues of stack size limitations. """ while self.stack: if self.stack[-1].wkids: node = self.stack[-1].wkids.pop(0) if not self.stack[-1].wkids: self.stack[-1].wkids = None if node in self.history: self.cycle_func(node, self.stack) else: node.wkids = copy.copy(self.kids_func(node, self.stack[-1])) self.stack.append(node) self.history[node] = None else: node = self.stack.pop() del self.history[node] if node: if self.stack: parent = self.stack[-1] else: parent = None self.eval_func(node, parent) return node return None
[docs] def is_done(self): return not self.stack
arg2nodes_lookups = [] # Local Variables: # tab-width:4 # indent-tabs-mode:nil # End: # vim: set expandtab tabstop=4 shiftwidth=4: