--- /dev/null
+#
+# Copyright (c) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008 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__ = "src/engine/SCons/PathList.py 3842 2008/12/20 22:59:52 scons"
+
+__doc__ = """SCons.PathList
+
+A module for handling lists of directory paths (the sort of things
+that get set as CPPPATH, LIBPATH, etc.) with as much caching of data and
+efficiency as we can while still keeping the evaluation delayed so that we
+Do the Right Thing (almost) regardless of how the variable is specified.
+
+"""
+
+import os
+import string
+
+import SCons.Memoize
+import SCons.Node
+import SCons.Util
+
+#
+# Variables to specify the different types of entries in a PathList object:
+#
+
+TYPE_STRING_NO_SUBST = 0 # string with no '$'
+TYPE_STRING_SUBST = 1 # string containing '$'
+TYPE_OBJECT = 2 # other object
+
+def node_conv(obj):
+ """
+ This is the "string conversion" routine that we have our substitutions
+ use to return Nodes, not strings. This relies on the fact that an
+ EntryProxy object has a get() method that returns the underlying
+ Node that it wraps, which is a bit of architectural dependence
+ that we might need to break or modify in the future in response to
+ additional requirements.
+ """
+ try:
+ get = obj.get
+ except AttributeError:
+ if isinstance(obj, SCons.Node.Node) or SCons.Util.is_Sequence( obj ):
+ result = obj
+ else:
+ result = str(obj)
+ else:
+ result = get()
+ return result
+
+class _PathList:
+ """
+ An actual PathList object.
+ """
+ def __init__(self, pathlist):
+ """
+ Initializes a PathList object, canonicalizing the input and
+ pre-processing it for quicker substitution later.
+
+ The stored representation of the PathList is a list of tuples
+ containing (type, value), where the "type" is one of the TYPE_*
+ variables defined above. We distinguish between:
+
+ strings that contain no '$' and therefore need no
+ delayed-evaluation string substitution (we expect that there
+ will be many of these and that we therefore get a pretty
+ big win from avoiding string substitution)
+
+ strings that contain '$' and therefore need substitution
+ (the hard case is things like '${TARGET.dir}/include',
+ which require re-evaluation for every target + source)
+
+ other objects (which may be something like an EntryProxy
+ that needs a method called to return a Node)
+
+ Pre-identifying the type of each element in the PathList up-front
+ and storing the type in the list of tuples is intended to reduce
+ the amount of calculation when we actually do the substitution
+ over and over for each target.
+ """
+ if SCons.Util.is_String(pathlist):
+ pathlist = string.split(pathlist, os.pathsep)
+ elif not SCons.Util.is_Sequence(pathlist):
+ pathlist = [pathlist]
+
+ pl = []
+ for p in pathlist:
+ try:
+ index = string.find(p, '$')
+ except (AttributeError, TypeError):
+ type = TYPE_OBJECT
+ else:
+ if index == -1:
+ type = TYPE_STRING_NO_SUBST
+ else:
+ type = TYPE_STRING_SUBST
+ pl.append((type, p))
+
+ self.pathlist = tuple(pl)
+
+ def __len__(self): return len(self.pathlist)
+
+ def __getitem__(self, i): return self.pathlist[i]
+
+ def subst_path(self, env, target, source):
+ """
+ Performs construction variable substitution on a pre-digested
+ PathList for a specific target and source.
+ """
+ result = []
+ for type, value in self.pathlist:
+ if type == TYPE_STRING_SUBST:
+ value = env.subst(value, target=target, source=source,
+ conv=node_conv)
+ if SCons.Util.is_Sequence(value):
+ result.extend(value)
+ continue
+
+ elif type == TYPE_OBJECT:
+ value = node_conv(value)
+ if value:
+ result.append(value)
+ return tuple(result)
+
+
+class PathListCache:
+ """
+ A class to handle caching of PathList lookups.
+
+ This class gets instantiated once and then deleted from the namespace,
+ so it's used as a Singleton (although we don't enforce that in the
+ usual Pythonic ways). We could have just made the cache a dictionary
+ in the module namespace, but putting it in this class allows us to
+ use the same Memoizer pattern that we use elsewhere to count cache
+ hits and misses, which is very valuable.
+
+ Lookup keys in the cache are computed by the _PathList_key() method.
+ Cache lookup should be quick, so we don't spend cycles canonicalizing
+ all forms of the same lookup key. For example, 'x:y' and ['x',
+ 'y'] logically represent the same list, but we don't bother to
+ split string representations and treat those two equivalently.
+ (Note, however, that we do, treat lists and tuples the same.)
+
+ The main type of duplication we're trying to catch will come from
+ looking up the same path list from two different clones of the
+ same construction environment. That is, given
+
+ env2 = env1.Clone()
+
+ both env1 and env2 will have the same CPPPATH value, and we can
+ cheaply avoid re-parsing both values of CPPPATH by using the
+ common value from this cache.
+ """
+ if SCons.Memoize.use_memoizer:
+ __metaclass__ = SCons.Memoize.Memoized_Metaclass
+
+ memoizer_counters = []
+
+ def __init__(self):
+ self._memo = {}
+
+ def _PathList_key(self, pathlist):
+ """
+ Returns the key for memoization of PathLists.
+
+ Note that we want this to be pretty quick, so we don't completely
+ canonicalize all forms of the same list. For example,
+ 'dir1:$ROOT/dir2' and ['$ROOT/dir1', 'dir'] may logically
+ represent the same list if you're executing from $ROOT, but
+ we're not going to bother splitting strings into path elements,
+ or massaging strings into Nodes, to identify that equivalence.
+ We just want to eliminate obvious redundancy from the normal
+ case of re-using exactly the same cloned value for a path.
+ """
+ if SCons.Util.is_Sequence(pathlist):
+ pathlist = tuple(SCons.Util.flatten(pathlist))
+ return pathlist
+
+ memoizer_counters.append(SCons.Memoize.CountDict('PathList', _PathList_key))
+
+ def PathList(self, pathlist):
+ """
+ Returns the cached _PathList object for the specified pathlist,
+ creating and caching a new object as necessary.
+ """
+ pathlist = self._PathList_key(pathlist)
+ try:
+ memo_dict = self._memo['PathList']
+ except KeyError:
+ memo_dict = {}
+ self._memo['PathList'] = memo_dict
+ else:
+ try:
+ return memo_dict[pathlist]
+ except KeyError:
+ pass
+
+ result = _PathList(pathlist)
+
+ memo_dict[pathlist] = result
+
+ return result
+
+PathList = PathListCache().PathList
+
+
+del PathListCache
projects / senf.git / blobdiff