"""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 Steven Knight # # 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__ = "__FILE__ __REVISION__ __DATE__ __DEVELOPER__" import copy import SCons.Sig 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 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): self.sources = [] # source files used to build node self.depends = [] # explicit dependencies (from Depends) self.implicit = None # implicit (scanned) dependencies (None means not scanned yet) self.ignore = [] # dependencies to ignore self.parents = {} self.wkids = None # Kids yet to walk, when it's an array self.builder = None self.source_scanner = None # implicit scanner from scanner map self.target_scanner = None # explicit scanner from this node's Builder self.env = None self.state = None self.precious = 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 def generate_build_env(self): return self.env.Override(self.overrides) def build(self): """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 None action_list = self.builder.get_actions() if not action_list: return targets = self.builder.targets(self) env = self.generate_build_env() for action in action_list: stat = action(targets, self.sources, env) if stat: raise SCons.Errors.BuildError(node = self, errstr = "Error %d" % stat) def built(self): """Called just after this node is sucessfully built.""" self.store_bsig() # Clear out the implicit dependency caches: # XXX this really should somehow be made more general and put # under the control of the scanners. if self.source_scanner: self.found_includes = {} self.includes = None def get_parents(node, parent): return node.get_parents() def clear_cache(node, parent): node.implicit = None node.del_bsig() w = Walker(self, get_parents, ignore_cycle, clear_cache) while w.next(): pass # clear out the content signature, since the contents of this # node were presumably just changed: self.del_csig() 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. """ return not self.builder is None def builder_sig_adapter(self): """Create an adapter for calculating a builder's signature. The underlying signature class will call get_contents() to fetch the signature of a builder, but the actual content of that signature depends on the node and the environment (for construction variable substitution), so this adapter provides the right glue between the two. """ class Adapter: def __init__(self, node): self.node = node def get_contents(self): return self.node.builder.get_contents(self.node, self.node.sources, self.node.generate_build_env()) def get_timestamp(self): return None return Adapter(self) 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 [] 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 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 = [] if not self.has_builder(): return if implicit_cache and not implicit_deps_changed: implicit = self.get_stored_implicit() if implicit is not None: implicit = map(self.builder.source_factory, implicit) self._add_child(self.implicit, implicit) calc = SCons.Sig.default_calc if implicit_deps_unchanged or calc.current(self, calc.bsig(self)): return else: # one of this node's sources has changed, so # we need to recalculate the implicit deps, # and the bsig: self.implicit = [] self.del_bsig() build_env = self.generate_build_env() for child in self.children(scan=0): self._add_child(self.implicit, child.get_implicit_deps(build_env, child.source_scanner, self)) # scan this node itself for implicit dependencies self._add_child(self.implicit, self.get_implicit_deps(build_env, self.target_scanner, self)) 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 calc_signature(self, calc): """ Select and calculate the appropriate build signature for a node. self - the node calc - the signature calculation module returns - the signature This method does not store the signature in the node or in the .sconsign file. """ if self.has_builder(): if SCons.Sig.build_signature: if not hasattr(self, 'bsig'): self.set_bsig(calc.bsig(self)) return self.get_bsig() else: if not hasattr(self, 'csig'): self.set_csig(calc.csig(self)) return self.get_csig() elif not self.exists(): return None else: if not hasattr(self, 'csig'): self.set_csig(calc.csig(self)) return self.get_csig() def get_bsig(self): """Get the node's build signature (based on the signatures of its dependency files and build information).""" if not hasattr(self, 'bsig'): return None return self.bsig def set_bsig(self, bsig): """Set the node's build signature (based on the signatures of its dependency files and build information).""" self.bsig = bsig def store_bsig(self): """Make the build signature permanent (that is, store it in the .sconsign file or equivalent).""" pass def del_bsig(self): """Delete the bsig from this node.""" if hasattr(self, 'bsig'): delattr(self, 'bsig') def get_csig(self): """Get the signature of the node's content.""" if not hasattr(self, 'csig'): return None return self.csig def set_csig(self, csig): """Set the signature of the node's content.""" self.csig = csig def store_csig(self): """Make the content signature permanent (that is, store it in the .sconsign file or equivalent).""" pass def del_csig(self): """Delete the csig from this node.""" if hasattr(self, 'csig'): delattr(self, 'csig') def get_prevsiginfo(self): """Fetch the previous signature information from the .sconsign entry.""" return None def get_timestamp(self): return 0 def store_timestamp(self): """Make the timestamp permanent (that is, store it in the .sconsign file or equivalent).""" pass def store_implicit(self): """Make the implicit deps permanent (that is, store them in the .sconsign file or equivalent).""" pass 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 prepare(self): """Prepare for this Node to be created: no-op by default.""" pass def remove(self): """Remove this Node: no-op by default.""" return None def add_dependency(self, depend): """Adds dependencies. The depend argument must be a list.""" self._add_child(self.depends, depend) def add_ignore(self, depend): """Adds dependencies to ignore. The depend argument must be a list.""" self._add_child(self.ignore, depend) def add_source(self, source): """Adds sources. The source argument must be a list.""" self._add_child(self.sources, source) def _add_child(self, collection, child): """Adds 'child' to 'collection'. The 'child' argument must be a list""" if type(child) is not type([]): raise TypeError("child must be a list") child = filter(lambda x, s=collection: x not in s, child) if child: collection.extend(child) for c in child: c.parents[self] = 1 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(self, scan=1): """Return a list of the node's direct children, minus those that are ignored by this node.""" return filter(lambda x, i=self.ignore: x not in i, self.all_children(scan)) 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 get_parents(self): return self.parents.keys() def set_state(self, state): self.state = state def get_state(self): return self.state def current(self, calc=None): return None def rfile(self): return self def rstr(self): return str(self) def is_literal(self): """Always pass the string representation of a Node to the command interpreter literally.""" return 1 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.has_builder() and self.env: env = self.generate_build_env() for s in self.sources: def f(node, env=env, scanner=s.source_scanner, target=self): return node.get_found_includes(env, scanner, target) return SCons.Util.render_tree(s, f, 1) else: return None 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 def is_done(self): return not self.stack arg2nodes_lookups = [] def arg2nodes(args, node_factory=None, lookup_list=arg2nodes_lookups): """This function converts a string or list into a list of Node instances. It accepts the following inputs: - A single string, - A single Node instance, - A list containing either strings or Node instances. In all cases, strings are converted to Node instances, and the function returns a list of Node instances.""" if not args: return [] if not SCons.Util.is_List(args): args = [args] nodes = [] for v in args: if SCons.Util.is_String(v): n = None for l in lookup_list: n = l(v) if not n is None: break if not n is None: if SCons.Util.is_String(n) and node_factory: n = node_factory(n) nodes.append(n) elif node_factory: nodes.append(node_factory(v)) # Do we enforce the following restriction? Maybe, but it # would also restrict what we can do to allow people to # use the engine with alternate Node implementations... #elif not issubclass(v.__class__, Node): # raise TypeError else: nodes.append(v) return nodes