"""SCons.Node 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." """ # # Copyright (c) 2001, 2002, 2003, 2004 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. # # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY # KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE # WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND # NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE # LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION # OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION # WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. # __revision__ = "/home/scons/scons/branch.0/baseline/src/engine/SCons/Node/__init__.py 0.96.1.D001 2004/08/23 09:55:29 knight" import copy import string from SCons.Debug import logInstanceCreation import SCons.SConsign import SCons.Util # 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. pending = 1 executing = 2 up_to_date = 3 executed = 4 failed = 5 stack = 6 # nodes that are in the current Taskmaster execution stack # controls whether implicit depedencies 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. def do_nothing(node): pass Annotate = do_nothing class BuildInfo: def __cmp__(self, other): return cmp(self.__dict__, other.__dict__) class Node: """The base Node class, for entities that we know how to build, or use to build other Nodes. """ class Attrs: pass def __init__(self): if __debug__: logInstanceCreation(self, '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_dict = {} self.depends = [] # explicit dependencies (from Depends) self.depends_dict = {} self.ignore = [] # dependencies to ignore self.ignore_dict = {} self.implicit = None # implicit (scanned) dependencies (None means not scanned yet) self.waiting_parents = [] self.wkids = None # Kids yet to walk, when it's an array self.target_scanner = None # explicit scanner from this node's Builder self.source_scanner = None self.backup_source_scanner = None self.env = None self.state = None self.precious = None self.always_build = None self.found_includes = {} self.includes = None self.overrides = {} # construction variable overrides for building this node 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.pre_actions = [] self.post_actions = [] self.linked = 0 # is this node linked to the build directory? # 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) def get_suffix(self): return '' def generate_build_dict(self): """Return an appropriate dictionary of values for building this Node.""" return {} def get_build_env(self): """Fetch the appropriate Environment to build this node.""" executor = self.get_executor() return executor.get_build_env() def set_executor(self, executor): """Set the action executor for this node.""" self.executor = executor 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 import SCons.Executor executor = SCons.Executor.Executor(self.builder.action, self.builder.env, [self.builder.overrides], [self], self.sources) self.executor = executor return executor 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 iff the node was successfully retrieved. """ return 0 def build(self, **kw): """Actually build the node. This method is called from multiple threads in a parallel build, so only do thread safe stuff here. Do thread unsafe stuff in built(). """ if not self.has_builder(): return def errfunc(stat, node=self): raise SCons.Errors.BuildError(node=node, errstr="Error %d" % stat) executor = self.get_executor() apply(executor, (self, errfunc), kw) def built(self): """Called just after this node is sucessfully built.""" try: new_binfo = self.binfo except AttributeError: pass else: self.store_info(new_binfo) # Clear our scanned included files. self.found_includes = {} self.includes = None # Clear the implicit dependency caches of any Nodes # waiting for this Node to be built. for parent in self.waiting_parents: parent.implicit = None parent.del_binfo() self.waiting_parents = [] # The content just changed, delete any cached info # so it will get recalculated. self.del_cinfo() def add_to_waiting_parents(self, node): self.waiting_parents.append(node) def call_for_all_waiting_parents(self, func): func(self) for parent in self.waiting_parents: parent.call_for_all_waiting_parents(func) def postprocess(self): """Clean up anything we don't need to hang onto after we've been built.""" try: executor = self.get_executor(create=None) except AttributeError: pass else: executor.cleanup() 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). """ self.set_state(None) self.del_binfo() self.del_cinfo() try: delattr(self, '_calculated_sig') except AttributeError: pass self.includes = None self.found_includes = {} self.implicit = None self.waiting_parents = [] def visited(self): """Called just after this node has been visited without requiring a build..""" pass def depends_on(self, nodes): """Does this node depend on any of 'nodes'?""" for node in nodes: if node in self.children(): return 1 return 0 def builder_set(self, builder): self.builder = builder 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 __nonzero__ 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. self.builder = None b = self.builder return not b is None multiple_side_effect_has_builder = has_builder def is_derived(self): """ Returns true iff this node is derived (i.e. built). This should return true only for nodes whose path should be in the build 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 self.has_builder() or self.side_effect def is_pseudo_derived(self): """ Returns true iff this node is built, but should use a source path when duplicate=0 and should contribute a content signature (i.e. source signature) when used as a source for other derived files. """ return 0 def alter_targets(self): """Return a list of alternate targets for this Node. """ return [], None def get_found_includes(self, env, scanner, target): """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 [] def get_implicit_deps(self, env, scanner, target): """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. """ if not scanner: return [] # Give the scanner a chance to select a more specific scanner # for this Node. scanner = scanner.select(self) try: recurse = scanner.recursive except AttributeError: recurse = None nodes = [self] seen = {} seen[self] = 1 deps = [] while nodes: n = nodes.pop(0) d = filter(lambda x, seen=seen: not seen.has_key(x), n.get_found_includes(env, scanner, target)) if d: deps.extend(d) for n in d: seen[n] = 1 if recurse: nodes.extend(d) return deps # cache used to make implicit_factory fast. implicit_factory_cache = {} def implicit_factory(self, path): """ Turn a cache implicit dependency path into a node. This is called so many times that doing caching here is a significant perforamnce boost. """ try: return self.implicit_factory_cache[path] except KeyError: n = self.builder.source_factory(path) self.implicit_factory_cache[path] = n return n 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. """ if self.source_scanner: return self.source_scanner try: scanner = node.builder.source_scanner if scanner: return scanner except AttributeError: pass return node.backup_source_scanner or None 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 not self.implicit is None: return self.implicit = [] self.implicit_dict = {} self._children_reset() if not self.has_builder(): return build_env = self.get_build_env() # 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: implicit = map(self.implicit_factory, implicit) self._add_child(self.implicit, self.implicit_dict, implicit) calc = build_env.get_calculator() if implicit_deps_unchanged or self.current(calc, scan=0): return else: # one of this node's sources has changed, so # we need to recalculate the implicit deps, # and the bsig: self.implicit = [] self.implicit_dict = {} self._children_reset() self.del_binfo() for child in self.children(scan=0): scanner = self.get_source_scanner(child) if scanner: deps = child.get_implicit_deps(build_env, scanner, self) self._add_child(self.implicit, self.implicit_dict, deps) # scan this node itself for implicit dependencies deps = self.get_implicit_deps(build_env, self.target_scanner, self) self._add_child(self.implicit, self.implicit_dict, deps) # XXX See note above re: --implicit-cache. #if implicit_cache: # self.store_implicit() def scanner_key(self): return None def env_set(self, env, safe=0): if safe and self.env: return self.env = env def calculator(self): import SCons.Defaults env = self.env or SCons.Defaults.DefaultEnvironment() return env.get_calculator() def calc_signature(self, calc=None): """ Select and calculate the appropriate build signature for a node. self - the node calc - the signature calculation module returns - the signature """ try: return self._calculated_sig except AttributeError: if self.is_derived(): import SCons.Defaults env = self.env or SCons.Defaults.DefaultEnvironment() if env.use_build_signature(): sig = self.calc_bsig(calc) else: sig = self.calc_csig(calc) elif not self.rexists(): sig = None else: sig = self.calc_csig(calc) self._calculated_sig = sig return sig def new_binfo(self): return BuildInfo() def del_binfo(self): """Delete the bsig from this node.""" try: delattr(self, 'binfo') except AttributeError: pass def calc_bsig(self, calc=None): try: return self.binfo.bsig except AttributeError: self.binfo = self.gen_binfo(calc) return self.binfo.bsig def gen_binfo(self, calc=None, scan=1): """ Generate a node's build signature, the digested signatures of its dependency files and 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. """ if calc is None: calc = self.calculator() binfo = self.new_binfo() if scan: self.scan() sources = self.filter_ignore(self.sources) depends = self.filter_ignore(self.depends) if self.implicit is None: implicit = [] else: implicit = self.filter_ignore(self.implicit) def calc_signature(node, calc=calc): return node.calc_signature(calc) sourcesigs = map(calc_signature, sources) dependsigs = map(calc_signature, depends) implicitsigs = map(calc_signature, implicit) sigs = sourcesigs + dependsigs + implicitsigs if self.has_builder(): executor = self.get_executor() binfo.bact = executor.get_contents() binfo.bactsig = calc.module.signature(executor) sigs.append(binfo.bactsig) binfo.bsources = map(str, sources) binfo.bdepends = map(str, depends) binfo.bimplicit = map(str, implicit) binfo.bsourcesigs = sourcesigs binfo.bdependsigs = dependsigs binfo.bimplicitsigs = implicitsigs binfo.bsig = calc.module.collect(filter(None, sigs)) return binfo def del_cinfo(self): try: del self.binfo.csig except AttributeError: pass def calc_csig(self, calc=None): try: binfo = self.binfo except AttributeError: binfo = self.binfo = self.new_binfo() try: return binfo.csig except AttributeError: if calc is None: calc = self.calculator() binfo.csig = calc.module.signature(self) self.store_info(binfo) return binfo.csig def store_info(self, obj): """Make the build signature permanent (that is, store it in the .sconsign file or equivalent).""" pass def get_stored_info(self): return None def get_stored_implicit(self): """Fetch the stored implicit dependencies""" return None def set_precious(self, precious = 1): """Set the Node's precious value.""" self.precious = precious def set_always_build(self, always_build = 1): """Set the Node's always_build value.""" self.always_build = always_build def exists(self): """Does this node exists?""" # All node exist by default: return 1 def rexists(self): """Does this node exist locally or in a repositiory?""" # There are no repositories by default: return self.exists() def prepare(self): """Prepare for this Node to be created. The default implemenation checks that all children either exist or are derived. """ def missing(node): return not node.is_derived() and \ not node.is_pseudo_derived() and \ not node.linked and \ not node.rexists() missing_sources = filter(missing, self.children()) if missing_sources: desc = "Source `%s' not found, needed by target `%s'." % (missing_sources[0], self) raise SCons.Errors.StopError, desc def remove(self): """Remove this Node: no-op by default.""" return None def add_dependency(self, depend): """Adds dependencies.""" try: self._add_child(self.depends, self.depends_dict, depend) except TypeError, e: e = e.args[0] if SCons.Util.is_List(e): s = 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))) def add_ignore(self, depend): """Adds dependencies to ignore.""" try: self._add_child(self.ignore, self.ignore_dict, depend) except TypeError, e: e = e.args[0] if SCons.Util.is_List(e): s = 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))) def add_source(self, source): """Adds sources.""" try: self._add_child(self.sources, self.sources_dict, source) except TypeError, e: e = e.args[0] if SCons.Util.is_List(e): s = 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))) def _add_child(self, collection, dict, child): """Adds 'child' to 'collection', first checking 'dict' to see if it's already present.""" if type(child) is not type([]): child = [child] for c in child: if not isinstance(c, Node): raise TypeError, c added = None for c in child: if not dict.has_key(c): collection.append(c) dict[c] = 1 added = 1 if added: self._children_reset() def add_wkid(self, wkid): """Add a node to the list of kids waiting to be evaluated""" if self.wkids != None: self.wkids.append(wkid) def _children_reset(self): try: delattr(self, '_children') except AttributeError: pass def filter_ignore(self, nodelist): ignore = self.ignore result = [] for node in nodelist: if node not in ignore: result.append(node) return result 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() try: return self._children except AttributeError: c = self.all_children(scan=0) self._children = self.filter_ignore(c) return self._children def all_children(self, scan=1): """Return a list of all the node's direct children.""" # 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 scan: self.scan() if self.implicit is None: return self.sources + self.depends else: return self.sources + self.depends + self.implicit def set_state(self, state): self.state = state def get_state(self): return self.state def current(self, calc=None): """Default check for whether the Node is current: unknown Node subtypes are always out of date, so they will always get built.""" return None def children_are_up_to_date(self, calc=None): """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.gen_binfo(calc) 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) def is_literal(self): """Always pass the string representation of a Node to the command interpreter literally.""" return 1 def add_pre_action(self, act): """Adds an Action performed on this Node only before building it.""" self.pre_actions.append(act) def add_post_action(self, act): """Adds and Action performed on this Node only after building it.""" self.post_actions.append(act) 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() and self.env: env = self.get_build_env() for s in self.sources: scanner = s.get_source_scanner(self) def f(node, env=env, scanner=scanner, target=self): return node.get_found_includes(env, scanner, target) return SCons.Util.render_tree(s, f, 1) else: return None 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) 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) 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 shoud 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) 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 def explain(self): if not self.exists(): return "building `%s' because it doesn't exist\n" % self old = self.get_stored_info() if old is None: return None def dictify(result, kids, sigs): for k, s in zip(kids, sigs): result[k] = s try: old_bkids = old.bsources + old.bdepends + old.bimplicit except AttributeError: return "Cannot explain why `%s' is being rebuilt: No previous build information found\n" % self osig = {} dictify(osig, old.bsources, old.bsourcesigs) dictify(osig, old.bdepends, old.bdependsigs) dictify(osig, old.bimplicit, old.bimplicitsigs) new_bsources = map(str, self.binfo.bsources) new_bdepends = map(str, self.binfo.bdepends) new_bimplicit = map(str, self.binfo.bimplicit) nsig = {} dictify(nsig, new_bsources, self.binfo.bsourcesigs) dictify(nsig, new_bdepends, self.binfo.bdependsigs) dictify(nsig, new_bimplicit, self.binfo.bimplicitsigs) new_bkids = new_bsources + new_bdepends + new_bimplicit lines = map(lambda x: "`%s' is no longer a dependency\n" % x, filter(lambda x, nk=new_bkids: not x in nk, old_bkids)) for k in new_bkids: if not k in old_bkids: lines.append("`%s' is a new dependency\n" % k) elif osig[k] != nsig[k]: lines.append("`%s' changed\n" % k) if len(lines) == 0 and old_bkids != new_bkids: lines.append("the dependency order changed:\n" + "%sold: %s\n" % (' '*15, old_bkids) + "%snew: %s\n" % (' '*15, new_bkids)) if len(lines) == 0: newact, newactsig = self.binfo.bact, self.binfo.bactsig if old.bact != newact: lines.append("the build action changed:\n" + "%sold: %s\n" % (' '*15, old.bact) + "%snew: %s\n" % (' '*15, newact)) if len(lines) == 0: return "rebuilding `%s' for unknown reasons" % self preamble = "rebuilding `%s' because" % self if len(lines) == 1: return "%s %s" % (preamble, lines[0]) else: lines = ["%s:\n" % preamble] + lines return string.join(lines, ' '*11) def get_children(node, parent): return node.children() def ignore_cycle(node, stack): pass def do_nothing(node, parent): pass 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 next() call. 'kids_func' is an optional function that will be called to 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 def 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 self.history.has_key(node): 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 def is_done(self): return not self.stack arg2nodes_lookups = []