Imported Upstream version 2.4.0upstream/2.4.0

8 files changed, 1102 insertions, 474 deletions

diff --git a/src/engine/SCons/Node/Alias.py b/src/engine/SCons/Node/Alias.py
index 0bd6422..7e13b00 100644
--- a/src/engine/SCons/Node/Alias.py
+++ b/src/engine/SCons/Node/Alias.py
@@ -30,7 +30,7 @@ This creates a hash of global Aliases (dummy targets).
 # WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 #
 
-__revision__ = "src/engine/SCons/Node/Alias.py rel_2.3.5:3347:d31d5a4e74b6 2015/07/31 14:36:10 bdbaddog"
+__revision__ = "src/engine/SCons/Node/Alias.py rel_2.4.0:3365:9259ea1c13d7 2015/09/21 14:03:43 bdbaddog"
 
 import collections
 
@@ -56,13 +56,47 @@ class AliasNameSpace(collections.UserDict):
             return None
 
 class AliasNodeInfo(SCons.Node.NodeInfoBase):
-    current_version_id = 1
+    __slots__ = ('csig',)
+    current_version_id = 2
     field_list = ['csig']
     def str_to_node(self, s):
         return default_ans.Alias(s)
 
+    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)
+          
+
 class AliasBuildInfo(SCons.Node.BuildInfoBase):
-    current_version_id = 1
+    __slots__ = ()
+    current_version_id = 2
 
 class Alias(SCons.Node.Node):
 
@@ -72,7 +106,9 @@ class Alias(SCons.Node.Node):
     def __init__(self, name):
         SCons.Node.Node.__init__(self)
         self.name = name
-
+        self.changed_since_last_build = 1
+        self.store_info = 0
+        
     def str_for_display(self):
         return '"' + self.__str__() + '"'
 
@@ -105,13 +141,6 @@ class Alias(SCons.Node.Node):
     #
     #
 
-    def changed_since_last_build(self, target, prev_ni):
-        cur_csig = self.get_csig()
-        try:
-            return cur_csig != prev_ni.csig
-        except AttributeError:
-            return 1
-
     def build(self):
         """A "builder" for aliases."""
         pass
diff --git a/src/engine/SCons/Node/AliasTests.py b/src/engine/SCons/Node/AliasTests.py
index 6b26f9b..0553c6f 100644
--- a/src/engine/SCons/Node/AliasTests.py
+++ b/src/engine/SCons/Node/AliasTests.py
@@ -21,7 +21,7 @@
 # WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 #
 
-__revision__ = "src/engine/SCons/Node/AliasTests.py rel_2.3.5:3347:d31d5a4e74b6 2015/07/31 14:36:10 bdbaddog"
+__revision__ = "src/engine/SCons/Node/AliasTests.py rel_2.4.0:3365:9259ea1c13d7 2015/09/21 14:03:43 bdbaddog"
 
 import sys
 import unittest
@@ -103,14 +103,14 @@ class AliasNodeInfoTestCase(unittest.TestCase):
         """Test AliasNodeInfo initialization"""
         ans = SCons.Node.Alias.AliasNameSpace()
         aaa = ans.Alias('aaa')
-        ni = SCons.Node.Alias.AliasNodeInfo(aaa)
+        ni = SCons.Node.Alias.AliasNodeInfo()
 
 class AliasBuildInfoTestCase(unittest.TestCase):
     def test___init__(self):
         """Test AliasBuildInfo initialization"""
         ans = SCons.Node.Alias.AliasNameSpace()
         aaa = ans.Alias('aaa')
-        bi = SCons.Node.Alias.AliasBuildInfo(aaa)
+        bi = SCons.Node.Alias.AliasBuildInfo()
 
 if __name__ == "__main__":
     suite = unittest.TestSuite()
diff --git a/src/engine/SCons/Node/FS.py b/src/engine/SCons/Node/FS.py
index 8d71f7e..b6a1bb5 100644
--- a/src/engine/SCons/Node/FS.py
+++ b/src/engine/SCons/Node/FS.py
@@ -32,7 +32,7 @@ that can be used by scripts or modules looking for the canonical default.
 # 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/Node/FS.py rel_2.3.5:3347:d31d5a4e74b6 2015/07/31 14:36:10 bdbaddog"
+__revision__ = "src/engine/SCons/Node/FS.py rel_2.4.0:3365:9259ea1c13d7 2015/09/21 14:03:43 bdbaddog"
 
 import fnmatch
 import os
@@ -56,10 +56,23 @@ import SCons.Warnings
 
 from SCons.Debug import Trace
 
-do_store_info = True
 print_duplicate = 0
 
 
+def sconsign_none(node):
+    raise NotImplementedError
+
+def sconsign_dir(node):
+    """Return the .sconsign file info for this directory,
+    creating it first if necessary."""
+    if not node._sconsign:
+        import SCons.SConsign
+        node._sconsign = SCons.SConsign.ForDirectory(node)
+    return node._sconsign
+
+_sconsign_map = {0 : sconsign_none,
+                 1 : sconsign_dir}
+
 class EntryProxyAttributeError(AttributeError):
     """
     An AttributeError subclass for recording and displaying the name
@@ -268,8 +281,8 @@ def LinkFunc(target, source, env):
     # who want to move their soft-linked src-trees around. Those
     # people should use the 'hard-copy' mode, softlinks cannot be
     # used for that; at least I have no idea how ...
-    src = source[0].abspath
-    dest = target[0].abspath
+    src = source[0].get_abspath()
+    dest = target[0].get_abspath()
     dir, file = os.path.split(dest)
     if dir and not target[0].fs.isdir(dir):
         os.makedirs(dir)
@@ -302,7 +315,7 @@ LocalCopy = SCons.Action.Action(LinkFunc, LocalString)
 
 def UnlinkFunc(target, source, env):
     t = target[0]
-    t.fs.unlink(t.abspath)
+    t.fs.unlink(t.get_abspath())
     return 0
 
 Unlink = SCons.Action.Action(UnlinkFunc, None)
@@ -310,7 +323,7 @@ Unlink = SCons.Action.Action(UnlinkFunc, None)
 def MkdirFunc(target, source, env):
     t = target[0]
     if not t.exists():
-        t.fs.mkdir(t.abspath)
+        t.fs.mkdir(t.get_abspath())
     return 0
 
 Mkdir = SCons.Action.Action(MkdirFunc, None, presub=None)
@@ -403,7 +416,7 @@ def do_diskcheck_match(node, predicate, errorfmt):
     except (AttributeError, KeyError):
         pass
     if result:
-        raise TypeError(errorfmt % node.abspath)
+        raise TypeError(errorfmt % node.get_abspath())
 
 def ignore_diskcheck_match(node, predicate, errorfmt):
     pass
@@ -573,7 +586,20 @@ class Base(SCons.Node.Node):
     object identity comparisons.
     """
 
-    memoizer_counters = []
+    __slots__ = ['name',
+                 'fs',
+                 '_abspath',
+                 '_labspath',
+                 '_path',
+                 '_tpath',
+                 '_path_elements',
+                 'dir',
+                 'cwd',
+                 'duplicate',
+                 '_local',
+                 'sbuilder',
+                 '_proxy',
+                 '_func_sconsign']
 
     def __init__(self, name, directory, fs):
         """Initialize a generic Node.FS.Base object.
@@ -591,27 +617,26 @@ class Base(SCons.Node.Node):
         #: Filename with extension as it was specified when the object was
         #: created; to obtain filesystem path, use Python str() function
         self.name = SCons.Util.silent_intern(name)
-        #: Cached filename extension
-        self.suffix = SCons.Util.silent_intern(SCons.Util.splitext(name)[1])
         self.fs = fs #: Reference to parent Node.FS object
 
         assert directory, "A directory must be provided"
 
-        self.abspath = SCons.Util.silent_intern(directory.entry_abspath(name))
-        self.labspath = SCons.Util.silent_intern(directory.entry_labspath(name))
-        if directory.path == '.':
-            self.path = SCons.Util.silent_intern(name)
-        else:
-            self.path = SCons.Util.silent_intern(directory.entry_path(name))
-        if directory.tpath == '.':
-            self.tpath = SCons.Util.silent_intern(name)
-        else:
-            self.tpath = SCons.Util.silent_intern(directory.entry_tpath(name))
-        self.path_elements = directory.path_elements + [self]
+        self._abspath = None
+        self._labspath = None
+        self._path = None
+        self._tpath = None
+        self._path_elements = None
 
         self.dir = directory
         self.cwd = None # will hold the SConscript directory for target nodes
         self.duplicate = directory.duplicate
+        self.changed_since_last_build = 2
+        self._func_sconsign = 0
+        self._func_exists = 2
+        self._func_rexists = 2
+        self._func_get_contents = 0
+        self._func_target_from_source = 1
+        self.store_info = 1
 
     def str_for_display(self):
         return '"' + self.__str__() + '"'
@@ -624,17 +649,38 @@ class Base(SCons.Node.Node):
         if isinstance(self, klass) or klass is Entry:
             return
         raise TypeError("Tried to lookup %s '%s' as a %s." %\
-              (self.__class__.__name__, self.path, klass.__name__))
+              (self.__class__.__name__, self.get_internal_path(), klass.__name__))
 
     def get_dir(self):
         return self.dir
 
     def get_suffix(self):
-        return self.suffix
+        return SCons.Util.splitext(self.name)[1]
 
     def rfile(self):
         return self
 
+    def __getattr__(self, attr):
+        """ Together with the node_bwcomp dict defined below,
+            this method provides a simple backward compatibility
+            layer for the Node attributes 'abspath', 'labspath',
+            'path', 'tpath', 'suffix' and 'path_elements'. These Node
+            attributes used to be directly available in v2.3 and earlier, but
+            have been replaced by getter methods that initialize the
+            single variables lazily when required, in order to save memory.
+            The redirection to the getters lets older Tools and
+            SConstruct continue to work without any additional changes,
+            fully transparent to the user. 
+            Note, that __getattr__ is only called as fallback when the
+            requested attribute can't be found, so there should be no
+            speed performance penalty involved for standard builds.
+        """
+        if attr in node_bwcomp:
+            return node_bwcomp[attr](self)
+        
+        raise AttributeError("%r object has no attribute %r" %
+                         (self.__class__, attr))
+
     def __str__(self):
         """A Node.FS.Base object's string representation is its path
         name."""
@@ -643,8 +689,7 @@ class Base(SCons.Node.Node):
             return self._save_str()
         return self._get_str()
 
-    memoizer_counters.append(SCons.Memoize.CountValue('_save_str'))
-
+    @SCons.Memoize.CountMethodCall
     def _save_str(self):
         try:
             return self._memo['_save_str']
@@ -681,21 +726,20 @@ class Base(SCons.Node.Node):
 
     rstr = __str__
 
-    memoizer_counters.append(SCons.Memoize.CountValue('stat'))
-
+    @SCons.Memoize.CountMethodCall
     def stat(self):
         try: return self._memo['stat']
         except KeyError: pass
-        try: result = self.fs.stat(self.abspath)
+        try: result = self.fs.stat(self.get_abspath())
         except os.error: result = None
         self._memo['stat'] = result
         return result
 
     def exists(self):
-        return self.stat() is not None
+        return SCons.Node._exists_map[self._func_exists](self)
 
     def rexists(self):
-        return self.rfile().exists()
+        return SCons.Node._rexists_map[self._func_rexists](self)
 
     def getmtime(self):
         st = self.stat()
@@ -717,7 +761,7 @@ class Base(SCons.Node.Node):
 
     if hasattr(os, 'symlink'):
         def islink(self):
-            try: st = self.fs.lstat(self.abspath)
+            try: st = self.fs.lstat(self.get_abspath())
             except os.error: return 0
             return stat.S_ISLNK(st[stat.ST_MODE])
     else:
@@ -752,7 +796,7 @@ class Base(SCons.Node.Node):
             dir = self.fs.getcwd()
         if self == dir:
             return '.'
-        path_elems = self.path_elements
+        path_elems = self.get_path_elements()
         pathname = ''
         try: i = path_elems.index(dir)
         except ValueError: 
@@ -785,7 +829,26 @@ class Base(SCons.Node.Node):
 
     def get_abspath(self):
         """Get the absolute path of the file."""
-        return self.abspath
+        return self.dir.entry_abspath(self.name)
+
+    def get_labspath(self):
+        """Get the absolute path of the file."""
+        return self.dir.entry_labspath(self.name)
+
+    def get_internal_path(self):
+        if self.dir._path == '.':
+            return self.name
+        else:
+            return self.dir.entry_path(self.name)
+        
+    def get_tpath(self):
+        if self.dir._tpath == '.':
+            return self.name
+        else:
+            return self.dir.entry_tpath(self.name)
+        
+    def get_path_elements(self):
+        return self.dir._path_elements + [self]
 
     def for_signature(self):
         # Return just our name.  Even an absolute path would not work,
@@ -811,13 +874,12 @@ class Base(SCons.Node.Node):
         files that need different behavior.  See Tool/swig.py for
         an example.
         """
-        return self.dir.Entry(prefix + splitext(self.name)[0] + suffix)
+        return SCons.Node._target_from_source_map[self._func_target_from_source](self, prefix, suffix, splitext)
 
     def _Rfindalldirs_key(self, pathlist):
         return pathlist
 
-    memoizer_counters.append(SCons.Memoize.CountDict('Rfindalldirs', _Rfindalldirs_key))
-
+    @SCons.Memoize.CountDictCall(_Rfindalldirs_key)
     def Rfindalldirs(self, pathlist):
         """
         Return all of the directories for a given path list, including
@@ -856,8 +918,7 @@ class Base(SCons.Node.Node):
         cwd = self.cwd or self.fs._cwd
         return cwd.Rfindalldirs(pathlist)
 
-    memoizer_counters.append(SCons.Memoize.CountValue('rentry'))
-
+    @SCons.Memoize.CountMethodCall
     def rentry(self):
         try:
             return self._memo['rentry']
@@ -878,6 +939,17 @@ class Base(SCons.Node.Node):
 
     def _glob1(self, pattern, ondisk=True, source=False, strings=False):
         return []
+    
+# Dict that provides a simple backward compatibility
+# layer for the Node attributes 'abspath', 'labspath',
+# 'path', 'tpath' and 'path_elements'.
+# @see Base.__getattr__ above
+node_bwcomp = {'abspath' : Base.get_abspath,
+               'labspath' : Base.get_labspath,
+               'path' : Base.get_internal_path,
+               'tpath' : Base.get_tpath,
+               'path_elements' : Base.get_path_elements,
+               'suffix' : Base.get_suffix}
 
 class Entry(Base):
     """This is the class for generic Node.FS entries--that is, things
@@ -887,6 +959,28 @@ class Entry(Base):
     time comes, and then call the same-named method in the transformed
     class."""
 
+    __slots__ = ['scanner_paths',
+                 'cachedir_csig',
+                 'cachesig',
+                 'repositories',
+                 'srcdir',
+                 'entries',
+                 'searched',
+                 '_sconsign',
+                 'variant_dirs',
+                 'root',
+                 'dirname',
+                 'on_disk_entries',
+                 'sccs_dir',
+                 'rcs_dir',
+                 'released_target_info',
+                 'contentsig']
+
+    def __init__(self, name, directory, fs):
+        Base.__init__(self, name, directory, fs)
+        self._func_exists = 3
+        self._func_get_contents = 1 
+
     def diskcheck_match(self):
         pass
 
@@ -917,7 +1011,7 @@ class Entry(Base):
                 self.__class__ = Dir
                 self._morph()
             elif must_exist:
-                msg = "No such file or directory: '%s'" % self.abspath
+                msg = "No such file or directory: '%s'" % self.get_abspath()
                 raise SCons.Errors.UserError(msg)
             else:
                 self.__class__ = File
@@ -939,17 +1033,7 @@ class Entry(Base):
     def get_contents(self):
         """Fetch the contents of the entry.  Returns the exact binary
         contents of the file."""
-        try:
-            self = self.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 self.get_contents()
+        return SCons.Node._get_contents_map[self._func_get_contents](self)
 
     def get_text_contents(self):
         """Fetch the decoded text contents of a Unicode encoded Entry.
@@ -989,10 +1073,7 @@ class Entry(Base):
     # to make various tests pass.
 
     def exists(self):
-        """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."""
-        return self.disambiguate().exists()
+        return SCons.Node._exists_map[self._func_exists](self)
 
     def rel_path(self, other):
         d = self.disambiguate()
@@ -1003,9 +1084,6 @@ class Entry(Base):
     def new_ninfo(self):
         return self.disambiguate().new_ninfo()
 
-    def changed_since_last_build(self, target, prev_ni):
-        return self.disambiguate().changed_since_last_build(target, prev_ni)
-
     def _glob1(self, pattern, ondisk=True, source=False, strings=False):
         return self.disambiguate()._glob1(pattern, ondisk, source, strings)
 
@@ -1019,9 +1097,6 @@ _classEntry = Entry
 
 class LocalFS(object):
 
-    if SCons.Memoize.use_memoizer:
-        __metaclass__ = SCons.Memoize.Memoized_Metaclass
-
     # This class implements an abstraction layer for operations involving
     # a local file system.  Essentially, this wraps any function in
     # the os, os.path or shutil modules that we use to actually go do
@@ -1101,8 +1176,6 @@ class LocalFS(object):
 
 class FS(LocalFS):
 
-    memoizer_counters = []
-
     def __init__(self, path = None):
         """Initialize the Node.FS subsystem.
 
@@ -1128,8 +1201,8 @@ class FS(LocalFS):
         self.defaultDrive = _my_normcase(_my_splitdrive(self.pathTop)[0])
 
         self.Top = self.Dir(self.pathTop)
-        self.Top.path = '.'
-        self.Top.tpath = '.'
+        self.Top._path = '.'
+        self.Top._tpath = '.'
         self._cwd = self.Top
 
         DirNodeInfo.fs = self
@@ -1160,7 +1233,7 @@ class FS(LocalFS):
             if dir is not None:
                 self._cwd = dir
                 if change_os_dir:
-                    os.chdir(dir.abspath)
+                    os.chdir(dir.get_abspath())
         except OSError:
             self._cwd = curr
             raise
@@ -1249,9 +1322,9 @@ class FS(LocalFS):
             
             # The path is relative to the top-level SCons directory.
             if p in ('', '.'):
-                p = directory.labspath
+                p = directory.get_labspath()
             else:
-                p = directory.labspath + '/' + p
+                p = directory.get_labspath() + '/' + p
         else:
             if do_splitdrive:
                 drive, p = _my_splitdrive(p)
@@ -1285,9 +1358,9 @@ class FS(LocalFS):
                     directory = self._cwd
 
                 if p in ('', '.'):
-                    p = directory.labspath
+                    p = directory.get_labspath()
                 else:
-                    p = directory.labspath + '/' + p
+                    p = directory.get_labspath() + '/' + p
 
                 if drive:
                     root = self.get_root(drive)
@@ -1393,7 +1466,7 @@ class FS(LocalFS):
                 if start_dir.is_under(bd):
                     # If already in the build-dir location, don't reflect
                     return [orig], fmt % str(orig)
-                p = os.path.join(bd.path, *tail)
+                p = os.path.join(bd._path, *tail)
                 targets.append(self.Entry(p))
             tail = [dir.name] + tail
             dir = dir.up()
@@ -1412,8 +1485,9 @@ class FS(LocalFS):
         return cwd.glob(pathname, ondisk, source, strings, exclude)
 
 class DirNodeInfo(SCons.Node.NodeInfoBase):
+    __slots__ = ()
     # This should get reset by the FS initialization.
-    current_version_id = 1
+    current_version_id = 2
 
     fs = None
 
@@ -1425,11 +1499,12 @@ class DirNodeInfo(SCons.Node.NodeInfoBase):
             if drive:
                 root = self.fs.get_root(drive)
         if not os.path.isabs(s):
-            s = top.labspath + '/' + s
+            s = top.get_labspath() + '/' + s
         return root._lookup_abs(s, Entry)
 
 class DirBuildInfo(SCons.Node.BuildInfoBase):
-    current_version_id = 1
+    __slots__ = ()
+    current_version_id = 2
 
 glob_magic_check = re.compile('[*?[]')
 
@@ -1440,7 +1515,22 @@ class Dir(Base):
     """A class for directories in a file system.
     """
 
-    memoizer_counters = []
+    __slots__ = ['scanner_paths',
+                 'cachedir_csig',
+                 'cachesig',
+                 'repositories',
+                 'srcdir',
+                 'entries',
+                 'searched',
+                 '_sconsign',
+                 'variant_dirs',
+                 'root',
+                 'dirname',
+                 'on_disk_entries',
+                 'sccs_dir',
+                 'rcs_dir',
+                 'released_target_info',
+                 'contentsig']
 
     NodeInfo = DirNodeInfo
     BuildInfo = DirBuildInfo
@@ -1470,6 +1560,22 @@ class Dir(Base):
         self._sconsign = None
         self.variant_dirs = []
         self.root = self.dir.root
+        self.changed_since_last_build = 3
+        self._func_sconsign = 1
+        self._func_exists = 2
+        self._func_get_contents = 2
+        
+        self._abspath = SCons.Util.silent_intern(self.dir.entry_abspath(self.name))
+        self._labspath = SCons.Util.silent_intern(self.dir.entry_labspath(self.name))
+        if self.dir._path == '.':
+            self._path = SCons.Util.silent_intern(self.name)
+        else:
+            self._path = SCons.Util.silent_intern(self.dir.entry_path(self.name))
+        if self.dir._tpath == '.':
+            self._tpath = SCons.Util.silent_intern(self.name)
+        else:
+            self._tpath = SCons.Util.silent_intern(self.dir.entry_tpath(self.name))
+        self._path_elements = self.dir._path_elements + [self]
 
         # For directories, we make a difference between the directory
         # 'name' and the directory 'dirname'. The 'name' attribute is
@@ -1562,8 +1668,7 @@ class Dir(Base):
             return self.srcdir.get_all_rdirs() + self.repositories
         return self.repositories
 
-    memoizer_counters.append(SCons.Memoize.CountValue('get_all_rdirs'))
-
+    @SCons.Memoize.CountMethodCall
     def get_all_rdirs(self):
         try:
             return list(self._memo['get_all_rdirs'])
@@ -1589,7 +1694,7 @@ class Dir(Base):
     def addRepository(self, dir):
         if dir != self and not dir in self.repositories:
             self.repositories.append(dir)
-            dir.tpath = '.'
+            dir._tpath = '.'
             self.__clearRepositoryCache()
 
     def up(self):
@@ -1598,8 +1703,7 @@ class Dir(Base):
     def _rel_path_key(self, other):
         return str(other)
 
-    memoizer_counters.append(SCons.Memoize.CountDict('rel_path', _rel_path_key))
-
+    @SCons.Memoize.CountDictCall(_rel_path_key)
     def rel_path(self, other):
         """Return a path to "other" relative to this directory.
         """
@@ -1628,7 +1732,7 @@ class Dir(Base):
         if self is other:
             result = '.'
 
-        elif not other in self.path_elements:
+        elif not other in self._path_elements:
             try:
                 other_dir = other.get_dir()
             except AttributeError:
@@ -1643,10 +1747,10 @@ class Dir(Base):
                     else:
                         result = dir_rel_path + OS_SEP + other.name
         else:
-            i = self.path_elements.index(other) + 1
+            i = self._path_elements.index(other) + 1
 
-            path_elems = ['..'] * (len(self.path_elements) - i) \
-                         + [n.name for n in other.path_elements[i:]]
+            path_elems = ['..'] * (len(self._path_elements) - i) \
+                         + [n.name for n in other._path_elements[i:]]
              
             result = OS_SEP.join(path_elems)
 
@@ -1713,7 +1817,7 @@ class Dir(Base):
             if p is None:
                 # Don't use while: - else: for this condition because
                 # if so, then parent is None and has no .path attribute.
-                raise SCons.Errors.StopError(parent.path)
+                raise SCons.Errors.StopError(parent._path)
             parent = p
         listDirs.reverse()
         for dirnode in listDirs:
@@ -1753,10 +1857,7 @@ class Dir(Base):
     def get_contents(self):
         """Return content signatures and names of all our children
         separated by new-lines. Ensure that the nodes are sorted."""
-        contents = []
-        for node in sorted(self.children(), key=lambda t: t.name):
-            contents.append('%s %s\n' % (node.get_csig(), node.name))
-        return ''.join(contents)
+        return SCons.Node._get_contents_map[self._func_get_contents](self)
 
     def get_csig(self):
         """Compute the content signature for Directory nodes. In
@@ -1770,8 +1871,6 @@ class Dir(Base):
     def do_duplicate(self, src):
         pass
 
-    changed_since_last_build = SCons.Node.Node.state_has_changed
-
     def is_up_to_date(self):
         """If any child is not up-to-date, then this directory isn't,
         either."""
@@ -1795,12 +1894,8 @@ class Dir(Base):
         return self
 
     def sconsign(self):
-        """Return the .sconsign file info for this directory,
-        creating it first if necessary."""
-        if not self._sconsign:
-            import SCons.SConsign
-            self._sconsign = SCons.SConsign.ForDirectory(self)
-        return self._sconsign
+        """Return the .sconsign file info for this directory. """
+        return _sconsign_map[self._func_sconsign](self)
 
     def srcnode(self):
         """Dir has a special need for srcnode()...if we
@@ -1817,17 +1912,34 @@ class Dir(Base):
                 stamp = kid.get_timestamp()
         return stamp
 
+    def get_abspath(self):
+        """Get the absolute path of the file."""
+        return self._abspath
+
+    def get_labspath(self):
+        """Get the absolute path of the file."""
+        return self._labspath
+
+    def get_internal_path(self):
+        return self._path
+        
+    def get_tpath(self):
+        return self._tpath
+        
+    def get_path_elements(self):
+        return self._path_elements
+
     def entry_abspath(self, name):
-        return self.abspath + OS_SEP + name
+        return self._abspath + OS_SEP + name
 
     def entry_labspath(self, name):
-        return self.labspath + '/' + name
+        return self._labspath + '/' + name
 
     def entry_path(self, name):
-        return self.path + OS_SEP + name
+        return self._path + OS_SEP + name
 
     def entry_tpath(self, name):
-        return self.tpath + OS_SEP + name
+        return self._tpath + OS_SEP + name
 
     def entry_exists_on_disk(self, name):
         """ Searches through the file/dir entries of the current
@@ -1841,7 +1953,7 @@ class Dir(Base):
         except AttributeError:
             d = {}
             try:
-                entries = os.listdir(self.abspath)
+                entries = os.listdir(self._abspath)
             except OSError:
                 pass
             else:
@@ -1854,7 +1966,7 @@ class Dir(Base):
             if result is None:
                 # Belt-and-suspenders for Windows:  check directly for
                 # 8.3 file names that don't show up in os.listdir().
-                result = os.path.exists(self.abspath + OS_SEP + name)
+                result = os.path.exists(self._abspath + OS_SEP + name)
                 d[name] = result
             return result
         else:
@@ -1887,8 +1999,7 @@ class Dir(Base):
                         break
         return rentry_exists
 
-    memoizer_counters.append(SCons.Memoize.CountValue('srcdir_list'))
-
+    @SCons.Memoize.CountMethodCall
     def srcdir_list(self):
         try:
             return self._memo['srcdir_list']
@@ -1929,8 +2040,7 @@ class Dir(Base):
     def _srcdir_find_file_key(self, filename):
         return filename
 
-    memoizer_counters.append(SCons.Memoize.CountDict('srcdir_find_file', _srcdir_find_file_key))
-
+    @SCons.Memoize.CountDictCall(_srcdir_find_file_key)
     def srcdir_find_file(self, filename):
         try:
             memo_dict = self._memo['srcdir_find_file']
@@ -2105,7 +2215,7 @@ class Dir(Base):
                 for name in node_names: selfEntry(name)
             if ondisk:
                 try:
-                    disk_names = os.listdir(dir.abspath)
+                    disk_names = os.listdir(dir._abspath)
                 except os.error:
                     continue
                 names.extend(disk_names)
@@ -2151,18 +2261,12 @@ class RootDir(Dir):
     add a separator when creating the path names of entries within
     this directory.
     """
+    
+    __slots__ = ['_lookupDict']
+    
     def __init__(self, drive, fs):
         if SCons.Debug.track_instances: logInstanceCreation(self, 'Node.FS.RootDir')
-        # We're going to be our own parent directory (".." entry and .dir
-        # attribute) so we have to set up some values so Base.__init__()
-        # won't gag won't it calls some of our methods.
-        self.abspath = ''
-        self.labspath = ''
-        self.path = ''
-        self.tpath = ''
-        self.path_elements = []
-        self.duplicate = 0
-        self.root = self
+        SCons.Node.Node.__init__(self)
 
         # Handle all the types of drives:
         if drive == '':
@@ -2178,33 +2282,85 @@ class RootDir(Dir):
             name = drive
             dirname = drive + OS_SEP
 
-        Base.__init__(self, name, self, fs)
+        #: Filename with extension as it was specified when the object was
+        #: created; to obtain filesystem path, use Python str() function
+        self.name = SCons.Util.silent_intern(name)
+        self.fs = fs #: Reference to parent Node.FS object
+
+        self._path_elements = [self]
+        self.dir = self
+        self._func_rexists = 2
+        self._func_target_from_source = 1
+        self.store_info = 1
 
         # Now set our paths to what we really want them to be. The
         # name should already contain any necessary separators, such
         # as the initial drive letter (the name) plus the directory
         # separator, except for the "lookup abspath," which does not
         # have the drive letter.
-        self.abspath = dirname
-        self.labspath = ''
-        self.path = dirname
-        self.tpath = dirname
-        self._morph()
-
-        # Must be reset after Dir._morph() is invoked...
+        self._abspath = dirname
+        self._labspath = ''
+        self._path = dirname
+        self._tpath = dirname
         self.dirname = dirname
 
+        self._morph()
+
+        self.duplicate = 0
         self._lookupDict = {}
 
         self._lookupDict[''] = self
         self._lookupDict['/'] = self
-
+        self.root = self
         # The // entry is necessary because os.path.normpath()
         # preserves double slashes at the beginning of a path on Posix
         # platforms.
         if not has_unc:
             self._lookupDict['//'] = self
 
+    def _morph(self):
+        """Turn a file system Node (either a freshly initialized directory
+        object or a separate Entry object) into a proper directory object.
+
+        Set up this directory's entries and hook it into the file
+        system tree.  Specify that directories (this Node) don't use
+        signatures for calculating whether they're current.
+        """
+
+        self.repositories = []
+        self.srcdir = None
+
+        self.entries = {}
+        self.entries['.'] = self
+        self.entries['..'] = self.dir
+        self.cwd = self
+        self.searched = 0
+        self._sconsign = None
+        self.variant_dirs = []
+        self.changed_since_last_build = 3
+        self._func_sconsign = 1
+        self._func_exists = 2
+        self._func_get_contents = 2
+        
+        # Don't just reset the executor, replace its action list,
+        # because it might have some pre-or post-actions that need to
+        # be preserved.
+        #
+        # But don't reset the executor if there is a non-null executor
+        # attached already. The existing executor might have other
+        # targets, in which case replacing the action list with a
+        # Mkdir action is a big mistake.
+        if not hasattr(self, 'executor'):
+            self.builder = get_MkdirBuilder()
+            self.get_executor().set_action_list(self.builder.action)
+        else:
+            # Prepend MkdirBuilder action to existing action list
+            l = self.get_executor().action_list
+            a = get_MkdirBuilder().action
+            l.insert(0, a) 
+            self.get_executor().set_action_list(l)
+      
+
     def must_be_same(self, klass):
         if klass is Dir:
             return
@@ -2253,19 +2409,19 @@ class RootDir(Dir):
         return result
 
     def __str__(self):
-        return self.abspath
+        return self._abspath
 
     def entry_abspath(self, name):
-        return self.abspath + name
+        return self._abspath + name
 
     def entry_labspath(self, name):
         return '/' + name
 
     def entry_path(self, name):
-        return self.path + name
+        return self._path + name
 
     def entry_tpath(self, name):
-        return self.tpath + name
+        return self._tpath + name
 
     def is_under(self, dir):
         if self is dir:
@@ -2283,7 +2439,8 @@ class RootDir(Dir):
         return _null
 
 class FileNodeInfo(SCons.Node.NodeInfoBase):
-    current_version_id = 1
+    __slots__ = ('csig', 'timestamp', 'size')
+    current_version_id = 2
 
     field_list = ['csig', 'timestamp', 'size']
 
@@ -2298,11 +2455,43 @@ class FileNodeInfo(SCons.Node.NodeInfoBase):
             if drive:
                 root = self.fs.get_root(drive)
         if not os.path.isabs(s):
-            s = top.labspath + '/' + s
+            s = top.get_labspath() + '/' + s
         return root._lookup_abs(s, Entry)
 
+    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)
+
 class FileBuildInfo(SCons.Node.BuildInfoBase):
-    current_version_id = 1
+    __slots__ = ()
+    current_version_id = 2
 
     def convert_to_sconsign(self):
         """
@@ -2317,7 +2506,7 @@ class FileBuildInfo(SCons.Node.BuildInfoBase):
         else:
             def node_to_str(n):
                 try:
-                    s = n.path
+                    s = n.get_internal_path()
                 except AttributeError:
                     s = str(n)
                 else:
@@ -2358,6 +2547,8 @@ class FileBuildInfo(SCons.Node.BuildInfoBase):
                 nodeinfos = getattr(self, sattr)
             except AttributeError:
                 continue
+            if strings is None or nodeinfos is None:
+                continue
             nodes = []
             for s, ni in zip(strings, nodeinfos):
                 if not isinstance(s, SCons.Node.Node):
@@ -2371,6 +2562,8 @@ class FileBuildInfo(SCons.Node.BuildInfoBase):
         for bkid, bkidsig in zip(bkids, bkidsigs):
             result.append(str(bkid) + ': ' +
                           ' '.join(bkidsig.format(names=names)))
+        if not hasattr(self,'bact'):
+            self.bact = "none"
         result.append('%s [%s]' % (self.bactsig, self.bact))
         return '\n'.join(result)
 
@@ -2378,7 +2571,22 @@ class File(Base):
     """A class for files in a file system.
     """
 
-    memoizer_counters = []
+    __slots__ = ['scanner_paths',
+                 'cachedir_csig',
+                 'cachesig',
+                 'repositories',
+                 'srcdir',
+                 'entries',
+                 'searched',
+                 '_sconsign',
+                 'variant_dirs',
+                 'root',
+                 'dirname',
+                 'on_disk_entries',
+                 'sccs_dir',
+                 'rcs_dir',
+                 'released_target_info',
+                 'contentsig']
 
     NodeInfo = FileNodeInfo
     BuildInfo = FileBuildInfo
@@ -2429,6 +2637,14 @@ class File(Base):
         if not hasattr(self, 'released_target_info'):
             self.released_target_info = False
 
+        self.store_info = 1
+        self._func_exists = 4
+        self._func_get_contents = 3
+        
+        # Initialize this Node's decider function to decide_source() because
+        # every file is a source file until it has a Builder attached...
+        self.changed_since_last_build = 4
+        
         # If there was already a Builder set on this entry, then
         # we need to make sure we call the target-decider function,
         # not the source-decider.  Reaching in and doing this by hand
@@ -2440,22 +2656,13 @@ class File(Base):
         # not clear right now how to fix that, stick with what works
         # until it becomes clear...
         if self.has_builder():
-            self.changed_since_last_build = self.decide_target
+            self.changed_since_last_build = 5
 
     def scanner_key(self):
         return self.get_suffix()
 
     def get_contents(self):
-        if not self.rexists():
-            return ''
-        fname = self.rfile().abspath
-        try:
-            contents = open(fname, "rb").read()
-        except EnvironmentError, e:
-            if not e.filename:
-                e.filename = fname
-            raise
-        return contents
+        return SCons.Node._get_contents_map[self._func_get_contents](self)
 
     # This attempts to figure out what the encoding of the text is
     # based upon the BOM bytes, and then decodes the contents so that
@@ -2482,7 +2689,7 @@ class File(Base):
         """
         if not self.rexists():
             return SCons.Util.MD5signature('')
-        fname = self.rfile().abspath
+        fname = self.rfile().get_abspath()
         try:
             cs = SCons.Util.MD5filesignature(fname,
                 chunksize=SCons.Node.FS.File.md5_chunksize*1024)
@@ -2492,9 +2699,7 @@ class File(Base):
             raise
         return cs
         
-
-    memoizer_counters.append(SCons.Memoize.CountValue('get_size'))
-
+    @SCons.Memoize.CountMethodCall
     def get_size(self):
         try:
             return self._memo['get_size']
@@ -2510,8 +2715,7 @@ class File(Base):
 
         return size
 
-    memoizer_counters.append(SCons.Memoize.CountValue('get_timestamp'))
-
+    @SCons.Memoize.CountMethodCall
     def get_timestamp(self):
         try:
             return self._memo['get_timestamp']
@@ -2527,14 +2731,6 @@ class File(Base):
 
         return timestamp
 
-    def store_info(self):
-        # Merge our build information into the already-stored entry.
-        # This accomodates "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:
-            self.dir.sconsign().store_info(self.name, self)
-
     convert_copy_attrs = [
         'bsources',
         'bimplicit',
@@ -2647,8 +2843,7 @@ class File(Base):
             delattr(old_entry, attr)
         return new_entry
 
-    memoizer_counters.append(SCons.Memoize.CountValue('get_stored_info'))
-
+    @SCons.Memoize.CountMethodCall
     def get_stored_info(self):
         try:
             return self._memo['get_stored_info']
@@ -2688,8 +2883,7 @@ class File(Base):
     def _get_found_includes_key(self, env, scanner, path):
         return (id(env), id(scanner), path)
 
-    memoizer_counters.append(SCons.Memoize.CountDict('get_found_includes', _get_found_includes_key))
-
+    @SCons.Memoize.CountDictCall(_get_found_includes_key)
     def get_found_includes(self, env, scanner, path):
         """Return the included implicit dependencies in this file.
         Cache results so we only scan the file once per path
@@ -2773,9 +2967,9 @@ class File(Base):
             # any build information that's stored in the .sconsign file
             # into our binfo object so it doesn't get lost.
             old = self.get_stored_info()
-            self.get_binfo().__dict__.update(old.binfo.__dict__)
+            self.get_binfo().merge(old.binfo)
 
-        self.store_info()
+        SCons.Node.store_info_map[self.store_info](self)
 
     def release_target_info(self):
         """Called just after this node has been marked
@@ -2875,7 +3069,7 @@ class File(Base):
 
     def _rmv_existing(self):
         self.clear_memoized_values()
-        if print_duplicate:
+        if SCons.Node.print_duplicate:
             print "dup: removing existing target %s"%self
         e = Unlink(self, [], None)
         if isinstance(e, SCons.Errors.BuildError):
@@ -2911,18 +3105,18 @@ class File(Base):
     def remove(self):
         """Remove this file."""
         if self.exists() or self.islink():
-            self.fs.unlink(self.path)
+            self.fs.unlink(self.get_internal_path())
             return 1
         return None
 
     def do_duplicate(self, src):
         self._createDir()
-        if print_duplicate:
+        if SCons.Node.print_duplicate:
             print "dup: relinking variant '%s' from '%s'"%(self, src)
         Unlink(self, None, None)
         e = Link(self, src, None)
         if isinstance(e, SCons.Errors.BuildError):
-            desc = "Cannot duplicate `%s' in `%s': %s." % (src.path, self.dir.path, e.errstr)
+            desc = "Cannot duplicate `%s' in `%s': %s." % (src.get_internal_path(), self.dir._path, e.errstr)
             raise SCons.Errors.StopError(desc)
         self.linked = 1
         # The Link() action may or may not have actually
@@ -2931,36 +3125,14 @@ class File(Base):
         # _rexists attributes so they can be reevaluated.
         self.clear()
 
-    memoizer_counters.append(SCons.Memoize.CountValue('exists'))
-
+    @SCons.Memoize.CountMethodCall
     def exists(self):
         try:
             return self._memo['exists']
         except KeyError:
             pass
-        # Duplicate from source path if we are set up to do this.
-        if self.duplicate and not self.is_derived() and not self.linked:
-            src = self.srcnode()
-            if src is not self:
-                # At this point, src is meant to be copied in a variant directory.
-                src = src.rfile()
-                if src.abspath != self.abspath:
-                    if src.exists():
-                        self.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"%self
-                        if Base.exists(self) or self.islink():
-                            self.fs.unlink(self.path)
-                        # Return None explicitly because the Base.exists() call
-                        # above will have cached its value if the file existed.
-                        self._memo['exists'] = None
-                        return None
-        result = Base.exists(self)
+        
+        result = SCons.Node._exists_map[self._func_exists](self)
         self._memo['exists'] = result
         return result
 
@@ -3037,7 +3209,7 @@ class File(Base):
 
     def builder_set(self, builder):
         SCons.Node.Node.builder_set(self, builder)
-        self.changed_since_last_build = self.decide_target
+        self.changed_since_last_build = 5
 
     def built(self):
         """Called just after this File node is successfully built.
@@ -3054,10 +3226,10 @@ class File(Base):
         if (not SCons.Node.interactive and 
             not hasattr(self.attributes, 'keep_targetinfo')):
             # Ensure that the build infos get computed and cached...        
-            self.store_info()
+            SCons.Node.store_info_map[self.store_info](self)
             # ... then release some more variables.
             self._specific_sources = False
-            self.labspath = None
+            self._labspath = None
             self._save_str()
             self.cwd = None
              
@@ -3116,16 +3288,6 @@ class File(Base):
         except AttributeError:
             return 1
 
-    def decide_source(self, target, prev_ni):
-        return target.get_build_env().decide_source(self, target, prev_ni)
-
-    def decide_target(self, target, prev_ni):
-        return target.get_build_env().decide_target(self, target, prev_ni)
-
-    # Initialize this Node's decider function to decide_source() because
-    # every file is a source file until it has a Builder attached...
-    changed_since_last_build = decide_source
-
     def is_up_to_date(self):
         T = 0
         if T: Trace('is_up_to_date(%s):' % self)
@@ -3143,7 +3305,7 @@ class File(Base):
                         e = LocalCopy(self, r, None)
                         if isinstance(e, SCons.Errors.BuildError):
                             raise 
-                        self.store_info()
+                        SCons.Node.store_info_map[self.store_info](self)
                     if T: Trace(' 1\n')
                     return 1
             self.changed()
@@ -3154,8 +3316,7 @@ class File(Base):
             if T: Trace(' self.exists():  %s\n' % r)
             return not r
 
-    memoizer_counters.append(SCons.Memoize.CountValue('rfile'))
-
+    @SCons.Memoize.CountMethodCall
     def rfile(self):
         try:
             return self._memo['rfile']
@@ -3257,7 +3418,7 @@ class File(Base):
         # Append this node's signature...
         sigs.append(self.get_contents_sig())
         # ...and it's path
-        sigs.append(self.path)
+        sigs.append(self.get_internal_path())
         # Merge this all into a single signature
         result = self.cachesig = SCons.Util.MD5collect(sigs)
         return result
@@ -3273,10 +3434,6 @@ def get_default_fs():
 class FileFinder(object):
     """
     """
-    if SCons.Memoize.use_memoizer:
-        __metaclass__ = SCons.Memoize.Memoized_Metaclass
-
-    memoizer_counters = []
 
     def __init__(self):
         self._memo = {}
@@ -3319,8 +3476,7 @@ class FileFinder(object):
     def _find_file_key(self, filename, paths, verbose=None):
         return (filename, paths)
         
-    memoizer_counters.append(SCons.Memoize.CountDict('find_file', _find_file_key))
-
+    @SCons.Memoize.CountDictCall(_find_file_key)
     def find_file(self, filename, paths, verbose=None):
         """
         find_file(str, [Dir()]) -> [nodes]
diff --git a/src/engine/SCons/Node/FSTests.py b/src/engine/SCons/Node/FSTests.py
index fde9550..7cda32d 100644
--- a/src/engine/SCons/Node/FSTests.py
+++ b/src/engine/SCons/Node/FSTests.py
@@ -22,7 +22,7 @@
 #
 from __future__ import division
 
-__revision__ = "src/engine/SCons/Node/FSTests.py rel_2.3.5:3347:d31d5a4e74b6 2015/07/31 14:36:10 bdbaddog"
+__revision__ = "src/engine/SCons/Node/FSTests.py rel_2.4.0:3365:9259ea1c13d7 2015/09/21 14:03:43 bdbaddog"
 
 import SCons.compat
 
@@ -130,34 +130,34 @@ class VariantDirTestCase(unittest.TestCase):
         fs.VariantDir('build', 'src')
         f2 = fs.File('build/test2')
         d1 = fs.Dir('build')
-        assert f1.srcnode().path == os.path.normpath('src/test1'), f1.srcnode().path
-        assert f2.srcnode().path == os.path.normpath('src/test2'), f2.srcnode().path
-        assert d1.srcnode().path == 'src', d1.srcnode().path
+        assert f1.srcnode().get_internal_path() == os.path.normpath('src/test1'), f1.srcnode().get_internal_path()
+        assert f2.srcnode().get_internal_path() == os.path.normpath('src/test2'), f2.srcnode().get_internal_path()
+        assert d1.srcnode().get_internal_path() == 'src', d1.srcnode().get_internal_path()
 
         fs = SCons.Node.FS.FS()
         f1 = fs.File('build/test1')
         fs.VariantDir('build', '.')
         f2 = fs.File('build/test2')
         d1 = fs.Dir('build')
-        assert f1.srcnode().path == 'test1', f1.srcnode().path
-        assert f2.srcnode().path == 'test2', f2.srcnode().path
-        assert d1.srcnode().path == '.', d1.srcnode().path
+        assert f1.srcnode().get_internal_path() == 'test1', f1.srcnode().get_internal_path()
+        assert f2.srcnode().get_internal_path() == 'test2', f2.srcnode().get_internal_path()
+        assert d1.srcnode().get_internal_path() == '.', d1.srcnode().get_internal_path()
 
         fs = SCons.Node.FS.FS()
         fs.VariantDir('build/var1', 'src')
         fs.VariantDir('build/var2', 'src')
         f1 = fs.File('build/var1/test1')
         f2 = fs.File('build/var2/test1')
-        assert f1.srcnode().path == os.path.normpath('src/test1'), f1.srcnode().path
-        assert f2.srcnode().path == os.path.normpath('src/test1'), f2.srcnode().path
+        assert f1.srcnode().get_internal_path() == os.path.normpath('src/test1'), f1.srcnode().get_internal_path()
+        assert f2.srcnode().get_internal_path() == os.path.normpath('src/test1'), f2.srcnode().get_internal_path()
 
         fs = SCons.Node.FS.FS()
         fs.VariantDir('../var1', 'src')
         fs.VariantDir('../var2', 'src')
         f1 = fs.File('../var1/test1')
         f2 = fs.File('../var2/test1')
-        assert f1.srcnode().path == os.path.normpath('src/test1'), f1.srcnode().path
-        assert f2.srcnode().path == os.path.normpath('src/test1'), f2.srcnode().path
+        assert f1.srcnode().get_internal_path() == os.path.normpath('src/test1'), f1.srcnode().get_internal_path()
+        assert f2.srcnode().get_internal_path() == os.path.normpath('src/test1'), f2.srcnode().get_internal_path()
 
         # Set up some files
         test.subdir('work', ['work', 'src'])
@@ -210,8 +210,8 @@ class VariantDirTestCase(unittest.TestCase):
         f2out_2.builder = 1
         fs.Repository(test.workpath('rep1'))
 
-        assert f1.srcnode().path == os.path.normpath('src/test.in'),\
-               f1.srcnode().path
+        assert f1.srcnode().get_internal_path() == os.path.normpath('src/test.in'),\
+               f1.srcnode().get_internal_path()
         # str(node) returns source path for duplicate = 0
         assert str(f1) == os.path.normpath('src/test.in'), str(f1)
         # Build path does not exist
@@ -221,11 +221,11 @@ class VariantDirTestCase(unittest.TestCase):
         # And duplicate=0 should also work just like a Repository
         assert f1.rexists()
         # rfile() should point to the source path
-        assert f1.rfile().path == os.path.normpath('src/test.in'),\
-               f1.rfile().path
+        assert f1.rfile().get_internal_path() == os.path.normpath('src/test.in'),\
+               f1.rfile().get_internal_path()
 
-        assert f2.srcnode().path == os.path.normpath('src/test.in'),\
-               f2.srcnode().path
+        assert f2.srcnode().get_internal_path() == os.path.normpath('src/test.in'),\
+               f2.srcnode().get_internal_path()
         # str(node) returns build path for duplicate = 1
         assert str(f2) == os.path.normpath('build/var2/test.in'), str(f2)
         # Build path exists
@@ -239,8 +239,8 @@ class VariantDirTestCase(unittest.TestCase):
         f3 = fs.File('build/var1/test2.in')
         f4 = fs.File('build/var2/test2.in')
 
-        assert f3.srcnode().path == os.path.normpath('src/test2.in'),\
-               f3.srcnode().path
+        assert f3.srcnode().get_internal_path() == os.path.normpath('src/test2.in'),\
+               f3.srcnode().get_internal_path()
         # str(node) returns source path for duplicate = 0
         assert str(f3) == os.path.normpath('src/test2.in'), str(f3)
         # Build path does not exist
@@ -250,11 +250,11 @@ class VariantDirTestCase(unittest.TestCase):
         # But we do have a file in the Repository
         assert f3.rexists()
         # rfile() should point to the source path
-        assert f3.rfile().path == os.path.normpath(test.workpath('rep1/src/test2.in')),\
-               f3.rfile().path
+        assert f3.rfile().get_internal_path() == os.path.normpath(test.workpath('rep1/src/test2.in')),\
+               f3.rfile().get_internal_path()
 
-        assert f4.srcnode().path == os.path.normpath('src/test2.in'),\
-               f4.srcnode().path
+        assert f4.srcnode().get_internal_path() == os.path.normpath('src/test2.in'),\
+               f4.srcnode().get_internal_path()
         # str(node) returns build path for duplicate = 1
         assert str(f4) == os.path.normpath('build/var2/test2.in'), str(f4)
         # Build path should exist
@@ -264,8 +264,8 @@ class VariantDirTestCase(unittest.TestCase):
         # should exist in repository, since exists() is true
         assert f4.rexists()
         # rfile() should point to ourselves
-        assert f4.rfile().path == os.path.normpath('build/var2/test2.in'),\
-               f4.rfile().path
+        assert f4.rfile().get_internal_path() == os.path.normpath('build/var2/test2.in'),\
+               f4.rfile().get_internal_path()
 
         f5 = fs.File('build/var1/test.out')
         f6 = fs.File('build/var2/test.out')
@@ -285,14 +285,14 @@ class VariantDirTestCase(unittest.TestCase):
 
         assert not f7.exists()
         assert f7.rexists()
-        r = f7.rfile().path
+        r = f7.rfile().get_internal_path()
         expect = os.path.normpath(test.workpath('rep1/build/var1/test2.out'))
         assert r == expect, (repr(r), repr(expect))
 
         assert not f8.exists()
         assert f8.rexists()
-        assert f8.rfile().path == os.path.normpath(test.workpath('rep1/build/var2/test2.out')),\
-               f8.rfile().path
+        assert f8.rfile().get_internal_path() == os.path.normpath(test.workpath('rep1/build/var2/test2.out')),\
+               f8.rfile().get_internal_path()
 
         # Verify the Mkdir and Link actions are called
         d9 = fs.Dir('build/var2/new_dir')
@@ -319,9 +319,9 @@ class VariantDirTestCase(unittest.TestCase):
             d9.reset_executor()
             f9.exists()
             expect = os.path.join('build', 'var2', 'new_dir')
-            assert dir_made[0].path == expect, dir_made[0].path
+            assert dir_made[0].get_internal_path() == expect, dir_made[0].get_internal_path()
             expect = os.path.join('build', 'var2', 'new_dir', 'test9.out')
-            assert link_made[0].path == expect, link_made[0].path
+            assert link_made[0].get_internal_path() == expect, link_made[0].get_internal_path()
             assert f9.linked
         finally:
             SCons.Node.FS.Link = save_Link
@@ -338,7 +338,7 @@ class VariantDirTestCase(unittest.TestCase):
 
         f11 = fs.File('src/file11')
         t, m = f11.alter_targets()
-        bdt = [n.path for n in t]
+        bdt = [n.get_internal_path() for n in t]
         var1_file11 = os.path.normpath('build/var1/file11')
         var2_file11 = os.path.normpath('build/var2/file11')
         assert bdt == [var1_file11, var2_file11], bdt
@@ -346,11 +346,11 @@ class VariantDirTestCase(unittest.TestCase):
         f12 = fs.File('src/file12')
         f12.builder = 1
         bdt, m = f12.alter_targets()
-        assert bdt == [], [n.path for n in bdt]
+        assert bdt == [], [n.get_internal_path() for n in bdt]
 
         d13 = fs.Dir('src/new_dir')
         t, m = d13.alter_targets()
-        bdt = [n.path for n in t]
+        bdt = [n.get_internal_path() for n in t]
         var1_new_dir = os.path.normpath('build/var1/new_dir')
         var2_new_dir = os.path.normpath('build/var2/new_dir')
         assert bdt == [var1_new_dir, var2_new_dir], bdt
@@ -566,13 +566,13 @@ class VariantDirTestCase(unittest.TestCase):
             f = dir + '/f'
             fnode = fs.File(dir + '/f')
 
-            dp = dnode.srcnode().path
+            dp = dnode.srcnode().get_internal_path()
             expect = os.path.normpath(srcnode_map.get(dir, dir))
             if dp != expect:
                 print "Dir `%s' srcnode() `%s' != expected `%s'" % (dir, dp, expect)
                 errors = errors + 1
 
-            fp = fnode.srcnode().path
+            fp = fnode.srcnode().get_internal_path()
             expect = os.path.normpath(srcnode_map.get(f, f))
             if fp != expect:
                 print "File `%s' srcnode() `%s' != expected `%s'" % (f, fp, expect)
@@ -584,14 +584,14 @@ class VariantDirTestCase(unittest.TestCase):
             fnode = fs.File(dir + '/f')
 
             t, m = dnode.alter_targets()
-            tp = t[0].path
+            tp = t[0].get_internal_path()
             expect = os.path.normpath(alter_map.get(dir, dir))
             if tp != expect:
                 print "Dir `%s' alter_targets() `%s' != expected `%s'" % (dir, tp, expect)
                 errors = errors + 1
 
             t, m = fnode.alter_targets()
-            tp = t[0].path
+            tp = t[0].get_internal_path()
             expect = os.path.normpath(alter_map.get(f, f))
             if tp != expect:
                 print "File `%s' alter_targets() `%s' != expected `%s'" % (f, tp, expect)
@@ -698,19 +698,19 @@ class DirNodeInfoTestCase(_tempdirTestCase):
     def test___init__(self):
         """Test DirNodeInfo initialization"""
         ddd = self.fs.Dir('ddd')
-        ni = SCons.Node.FS.DirNodeInfo(ddd)
+        ni = SCons.Node.FS.DirNodeInfo()
 
 class DirBuildInfoTestCase(_tempdirTestCase):
     def test___init__(self):
         """Test DirBuildInfo initialization"""
         ddd = self.fs.Dir('ddd')
-        bi = SCons.Node.FS.DirBuildInfo(ddd)
+        bi = SCons.Node.FS.DirBuildInfo()
 
 class FileNodeInfoTestCase(_tempdirTestCase):
     def test___init__(self):
         """Test FileNodeInfo initialization"""
         fff = self.fs.File('fff')
-        ni = SCons.Node.FS.FileNodeInfo(fff)
+        ni = SCons.Node.FS.FileNodeInfo()
         assert isinstance(ni, SCons.Node.FS.FileNodeInfo)
 
     def test_update(self):
@@ -718,7 +718,7 @@ class FileNodeInfoTestCase(_tempdirTestCase):
         test = self.test
         fff = self.fs.File('fff')
 
-        ni = SCons.Node.FS.FileNodeInfo(fff)
+        ni = SCons.Node.FS.FileNodeInfo()
 
         test.write('fff', "fff\n")
 
@@ -765,37 +765,41 @@ class FileBuildInfoTestCase(_tempdirTestCase):
     def test___init__(self):
         """Test File.BuildInfo initialization"""
         fff = self.fs.File('fff')
-        bi = SCons.Node.FS.FileBuildInfo(fff)
+        bi = SCons.Node.FS.FileBuildInfo()
         assert bi, bi
 
     def test_convert_to_sconsign(self):
         """Test converting to .sconsign file format"""
         fff = self.fs.File('fff')
-        bi = SCons.Node.FS.FileBuildInfo(fff)
+        bi = SCons.Node.FS.FileBuildInfo()
         assert hasattr(bi, 'convert_to_sconsign')
 
     def test_convert_from_sconsign(self):
         """Test converting from .sconsign file format"""
         fff = self.fs.File('fff')
-        bi = SCons.Node.FS.FileBuildInfo(fff)
+        bi = SCons.Node.FS.FileBuildInfo()
         assert hasattr(bi, 'convert_from_sconsign')
 
     def test_prepare_dependencies(self):
         """Test that we have a prepare_dependencies() method"""
         fff = self.fs.File('fff')
-        bi = SCons.Node.FS.FileBuildInfo(fff)
+        bi = SCons.Node.FS.FileBuildInfo()
         bi.prepare_dependencies()
 
     def test_format(self):
         """Test the format() method"""
         f1 = self.fs.File('f1')
-        bi1 = SCons.Node.FS.FileBuildInfo(f1)
+        bi1 = SCons.Node.FS.FileBuildInfo()
 
-        s1sig = SCons.Node.FS.FileNodeInfo(self.fs.File('n1'))
+        self.fs.File('n1')
+        self.fs.File('n2')
+        self.fs.File('n3')
+
+        s1sig = SCons.Node.FS.FileNodeInfo()
         s1sig.csig = 1
-        d1sig = SCons.Node.FS.FileNodeInfo(self.fs.File('n2'))
+        d1sig = SCons.Node.FS.FileNodeInfo()
         d1sig.timestamp = 2
-        i1sig = SCons.Node.FS.FileNodeInfo(self.fs.File('n3'))
+        i1sig = SCons.Node.FS.FileNodeInfo()
         i1sig.size = 3
 
         bi1.bsources = [self.fs.File('s1')]
@@ -953,7 +957,7 @@ class FSTestCase(_tempdirTestCase):
         assert isinstance(f1, SCons.Node.FS.File)
 
         d1_f1 = os.path.join('d1', 'f1')
-        assert f1.path == d1_f1, "f1.path %s != %s" % (f1.path, d1_f1)
+        assert f1.get_internal_path() == d1_f1, "f1.path %s != %s" % (f1.get_internal_path(), d1_f1)
         assert str(f1) == d1_f1, "str(f1) %s != %s" % (str(f1), d1_f1)
 
         x1 = d1.File('x1')
@@ -1045,16 +1049,16 @@ class FSTestCase(_tempdirTestCase):
                     name = os.sep
 
             if dir.up() is None:
-                dir_up_path =  dir.path
+                dir_up_path =  dir.get_internal_path()
             else:
-                dir_up_path =  dir.up().path
+                dir_up_path =  dir.up().get_internal_path()
 
             assert dir.name == name, \
                    "dir.name %s != expected name %s" % \
                    (dir.name, name)
-            assert dir.path == path, \
+            assert dir.get_internal_path() == path, \
                    "dir.path %s != expected path %s" % \
-                   (dir.path, path)
+                   (dir.get_internal_path(), path)
             assert str(dir) == path, \
                    "str(dir) %s != expected path %s" % \
                    (str(dir), path)
@@ -1136,9 +1140,9 @@ class FSTestCase(_tempdirTestCase):
         # Test for a bug in 0.04 that did not like looking up
         # dirs with a trailing slash on Windows.
         d=fs.Dir('./')
-        assert d.path == '.', d.abspath
+        assert d.get_internal_path() == '.', d.get_abspath()
         d=fs.Dir('foo/')
-        assert d.path == 'foo', d.abspath
+        assert d.get_internal_path() == 'foo', d.get_abspath()
 
         # Test for sub-classing of node building.
         global built_it
@@ -1167,50 +1171,50 @@ class FSTestCase(_tempdirTestCase):
 
         e1 = fs.Entry("d1")
         assert e1.__class__.__name__ == 'Dir'
-        match(e1.path, "d1")
-        match(e1.dir.path, ".")
+        match(e1.get_internal_path(), "d1")
+        match(e1.dir.get_internal_path(), ".")
 
         e2 = fs.Entry("d1/f1")
         assert e2.__class__.__name__ == 'File'
-        match(e2.path, "d1/f1")
-        match(e2.dir.path, "d1")
+        match(e2.get_internal_path(), "d1/f1")
+        match(e2.dir.get_internal_path(), "d1")
 
         e3 = fs.Entry("e3")
         assert e3.__class__.__name__ == 'Entry'
-        match(e3.path, "e3")
-        match(e3.dir.path, ".")
+        match(e3.get_internal_path(), "e3")
+        match(e3.dir.get_internal_path(), ".")
 
         e4 = fs.Entry("d1/e4")
         assert e4.__class__.__name__ == 'Entry'
-        match(e4.path, "d1/e4")
-        match(e4.dir.path, "d1")
+        match(e4.get_internal_path(), "d1/e4")
+        match(e4.dir.get_internal_path(), "d1")
 
         e5 = fs.Entry("e3/e5")
         assert e3.__class__.__name__ == 'Dir'
-        match(e3.path, "e3")
-        match(e3.dir.path, ".")
+        match(e3.get_internal_path(), "e3")
+        match(e3.dir.get_internal_path(), ".")
         assert e5.__class__.__name__ == 'Entry'
-        match(e5.path, "e3/e5")
-        match(e5.dir.path, "e3")
+        match(e5.get_internal_path(), "e3/e5")
+        match(e5.dir.get_internal_path(), "e3")
 
         e6 = fs.Dir("d1/e4")
         assert e6 is e4
         assert e4.__class__.__name__ == 'Dir'
-        match(e4.path, "d1/e4")
-        match(e4.dir.path, "d1")
+        match(e4.get_internal_path(), "d1/e4")
+        match(e4.dir.get_internal_path(), "d1")
 
         e7 = fs.File("e3/e5")
         assert e7 is e5
         assert e5.__class__.__name__ == 'File'
-        match(e5.path, "e3/e5")
-        match(e5.dir.path, "e3")
+        match(e5.get_internal_path(), "e3/e5")
+        match(e5.dir.get_internal_path(), "e3")
 
         fs.chdir(fs.Dir('subdir'))
         f11 = fs.File("f11")
-        match(f11.path, "subdir/f11")
+        match(f11.get_internal_path(), "subdir/f11")
         d12 = fs.Dir("d12")
         e13 = fs.Entry("subdir/e13")
-        match(e13.path, "subdir/subdir/e13")
+        match(e13.get_internal_path(), "subdir/subdir/e13")
         fs.chdir(fs.Dir('..'))
 
         # Test scanning
@@ -1220,13 +1224,13 @@ class FSTestCase(_tempdirTestCase):
         f1.builder.target_scanner = Scanner(xyz)
 
         f1.scan()
-        assert f1.implicit[0].path == "xyz"
+        assert f1.implicit[0].get_internal_path() == "xyz"
         f1.implicit = []
         f1.scan()
         assert f1.implicit == []
         f1.implicit = None
         f1.scan()
-        assert f1.implicit[0].path == "xyz"
+        assert f1.implicit[0].get_internal_path() == "xyz"
 
         # Test underlying scanning functionality in get_found_includes()
         env = Environment()
@@ -1284,9 +1288,9 @@ class FSTestCase(_tempdirTestCase):
         fs.chdir(fs.Dir('subdir'))
         # The cwd's path is always "."
         assert str(fs.getcwd()) == ".", str(fs.getcwd())
-        assert fs.getcwd().path == 'subdir', fs.getcwd().path
+        assert fs.getcwd().get_internal_path() == 'subdir', fs.getcwd().get_internal_path()
         fs.chdir(fs.Dir('../..'))
-        assert fs.getcwd().path == test.workdir, fs.getcwd().path
+        assert fs.getcwd().get_internal_path() == test.workdir, fs.getcwd().get_internal_path()
 
         f1 = fs.File(test.workpath("do_i_exist"))
         assert not f1.exists()
@@ -1589,15 +1593,15 @@ class FSTestCase(_tempdirTestCase):
             assert dir.name == name, \
                    "dir.name %s != expected name %s" % \
                    (dir.name, name)
-            assert dir.path == path, \
+            assert dir.get_internal_path() == path, \
                    "dir.path %s != expected path %s" % \
-                   (dir.path, path)
+                   (dir.get_internal_path(), path)
             assert str(dir) == path, \
                    "str(dir) %s != expected path %s" % \
                    (str(dir), path)
-            assert dir.up().path == up_path, \
+            assert dir.up().get_internal_path() == up_path, \
                    "dir.up().path %s != expected parent path %s" % \
-                   (dir.up().path, up_path)
+                   (dir.up().get_internal_path(), up_path)
 
         save_os_path = os.path
         save_os_sep = os.sep
@@ -1691,22 +1695,22 @@ class FSTestCase(_tempdirTestCase):
                 name = path.split(os.sep)[-1]
 
             if dir.up() is None:
-                dir_up_path =  dir.path
+                dir_up_path =  dir.get_internal_path()
             else:
-                dir_up_path =  dir.up().path
+                dir_up_path =  dir.up().get_internal_path()
 
             assert dir.name == name, \
                    "dir.name %s != expected name %s" % \
                    (dir.name, name)
-            assert dir.path == path, \
+            assert dir.get_internal_path() == path, \
                    "dir.path %s != expected path %s" % \
-                   (dir.path, path)
+                   (dir.get_internal_path(), path)
             assert str(dir) == path, \
                    "str(dir) %s != expected path %s" % \
                    (str(dir), path)
             assert dir_up_path == up_path, \
                    "dir.up().path %s != expected parent path %s" % \
-                   (dir.up().path, up_path)
+                   (dir.up().get_internal_path(), up_path)
 
         save_os_path = os.path
         save_os_sep = os.sep
@@ -1792,7 +1796,7 @@ class FSTestCase(_tempdirTestCase):
 
         d1 = fs.Dir('d1')
         d2 = d1.Dir('d2')
-        dirs = os.path.normpath(d2.abspath).split(os.sep)
+        dirs = os.path.normpath(d2.get_abspath()).split(os.sep)
         above_path = os.path.join(*['..']*len(dirs) + ['above'])
         above = d2.Dir(above_path)
 
@@ -1831,9 +1835,9 @@ class FSTestCase(_tempdirTestCase):
         fs = self.fs
         if sys.platform not in ('win32',):
             return
-        p = fs.Dir(r"\\computername\sharename").abspath
+        p = fs.Dir(r"\\computername\sharename").get_abspath()
         assert p == r"\\computername\sharename", p
-        p = fs.Dir(r"\\\computername\sharename").abspath
+        p = fs.Dir(r"\\\computername\sharename").get_abspath()
         assert p == r"\\computername\sharename", p
 
     def test_rel_path(self):
@@ -1980,7 +1984,7 @@ class DirTestCase(_tempdirTestCase):
         fs.Dir(os.path.join('ddd', 'd1', 'f4'))
         fs.Dir(os.path.join('ddd', 'd1', 'f5'))
         dir.scan()
-        kids = sorted([x.path for x in dir.children(None)])
+        kids = sorted([x.get_internal_path() for x in dir.children(None)])
         assert kids == [os.path.join('ddd', 'd1'),
                         os.path.join('ddd', 'f1'),
                         os.path.join('ddd', 'f2'),
@@ -2024,12 +2028,12 @@ class DirTestCase(_tempdirTestCase):
 
         fs.File(os.path.join('ddd', 'f1'))
         dir.scan()
-        kids = sorted([x.path for x in dir.children()])
+        kids = sorted([x.get_internal_path() for x in dir.children()])
         assert kids == [os.path.join('ddd', 'f1')], kids
 
         fs.File(os.path.join('ddd', 'f2'))
         dir.scan()
-        kids = sorted([x.path for x in dir.children()])
+        kids = sorted([x.get_internal_path() for x in dir.children()])
         assert kids == [os.path.join('ddd', 'f1'),
                         os.path.join('ddd', 'f2')], kids
 
@@ -2171,8 +2175,12 @@ class DirTestCase(_tempdirTestCase):
         """
         test = self.test
 
-        return_true = lambda: 1
+        def return_true(node):
+            return 1
 
+        SCons.Node._is_derived_map[2] = return_true
+        SCons.Node._exists_map[5] = return_true
+        
         test.subdir('src0')
         test.write(['src0', 'on-disk-f1'], "src0/on-disk-f1\n")
         test.write(['src0', 'on-disk-f2'], "src0/on-disk-f2\n")
@@ -2184,14 +2192,14 @@ class DirTestCase(_tempdirTestCase):
         self.fs.VariantDir(bld0, src0, duplicate=0)
 
         derived_f = src0.File('derived-f')
-        derived_f.is_derived = return_true
+        derived_f._func_is_derived = 2
         exists_f = src0.File('exists-f')
-        exists_f.exists = return_true
+        exists_f._func_exists = 5
 
         derived_e = src0.Entry('derived-e')
-        derived_e.is_derived = return_true
+        derived_e._func_is_derived = 2
         exists_e = src0.Entry('exists-e')
-        exists_e.exists = return_true
+        exists_e._func_exists = 5
 
         def check(result, expect):
             result = list(map(str, result))
@@ -2245,14 +2253,14 @@ class DirTestCase(_tempdirTestCase):
         self.fs.VariantDir(bld1, src1, duplicate=1)
 
         derived_f = src1.File('derived-f')
-        derived_f.is_derived = return_true
+        derived_f._func_is_derived = 2
         exists_f = src1.File('exists-f')
-        exists_f.exists = return_true
+        exists_f._func_exists = 5
 
         derived_e = src1.Entry('derived-e')
-        derived_e.is_derived = return_true
+        derived_e._func_is_derived = 2
         exists_e = src1.Entry('exists-e')
-        exists_e.exists = return_true
+        exists_e._func_exists = 5
 
         # First check from the source directory.
         n = src1.srcdir_find_file('does_not_exist')
@@ -2432,7 +2440,7 @@ class FileTestCase(_tempdirTestCase):
         build_f1 = fs.File('build/f1')
 
         assert build_f1.exists(), "%s did not realize that %s exists" % (build_f1, src_f1)
-        assert os.path.exists(build_f1.abspath), "%s did not get duplicated on disk" % build_f1.abspath
+        assert os.path.exists(build_f1.get_abspath()), "%s did not get duplicated on disk" % build_f1.get_abspath()
 
         test.unlink(['src', 'f1'])
         src_f1.clear()  # so the next exists() call will look on disk again
@@ -2441,7 +2449,7 @@ class FileTestCase(_tempdirTestCase):
         build_f1.clear()
         build_f1.linked = None
         assert not build_f1.exists(), "%s did not realize that %s disappeared" % (build_f1, src_f1)
-        assert not os.path.exists(build_f1.abspath), "%s did not get removed after %s was removed" % (build_f1, src_f1)
+        assert not os.path.exists(build_f1.get_abspath()), "%s did not get removed after %s was removed" % (build_f1, src_f1)
 
 
 
@@ -2535,7 +2543,7 @@ class GlobTestCase(_tempdirTestCase):
         for input, string_expect, node_expect in cases:
             r = self.fs.Glob(input, **kwargs)
             if node_expect:
-                r = sorted(r, key=lambda a: a.path)
+                r = sorted(r, key=lambda a: a.get_internal_path())
                 result = []
                 for n in node_expect:
                     if isinstance(n, str):
@@ -2906,8 +2914,14 @@ class RepositoryTestCase(_tempdirTestCase):
 
     def test_rdir(self):
         """Test the Dir.rdir() method"""
-        return_true = lambda: 1
-        return_false = lambda: 0
+        def return_true(obj):
+            return 1
+        def return_false(obj):
+            return 0
+        SCons.Node._exists_map[5] = return_true
+        SCons.Node._exists_map[6] = return_false
+        SCons.Node._is_derived_map[2] = return_true
+        SCons.Node._is_derived_map[3] = return_false
 
         d1 = self.fs.Dir('d1')
         d2 = self.fs.Dir('d2')
@@ -2931,19 +2945,19 @@ class RepositoryTestCase(_tempdirTestCase):
         assert r == os.path.join(self.rep3, 'd3'), r
 
         e1 = self.fs.Dir('e1')
-        e1.exists = return_false
+        e1._func_exists = 6
         e2 = self.fs.Dir('e2')
-        e2.exists = return_false
+        e2._func_exists = 6
 
         # Make sure we match entries in repositories,
         # regardless of whether they're derived or not.
 
         re1 = self.fs.Entry(os.path.join(self.rep1, 'e1'))
-        re1.exists = return_true
-        re1.is_derived = return_true
+        re1._func_exists = 5
+        re1._func_is_derived = 2
         re2 = self.fs.Entry(os.path.join(self.rep2, 'e2'))
-        re2.exists = return_true
-        re2.is_derived = return_false
+        re2._func_exists = 5
+        re2._func_is_derived = 3
 
         r = e1.rdir()
         assert r is re1, r
@@ -2953,8 +2967,14 @@ class RepositoryTestCase(_tempdirTestCase):
 
     def test_rfile(self):
         """Test the File.rfile() method"""
-        return_true = lambda: 1
-        return_false = lambda: 0
+        def return_true(obj):
+            return 1
+        def return_false(obj):
+            return 0
+        SCons.Node._exists_map[5] = return_true
+        SCons.Node._exists_map[6] = return_false
+        SCons.Node._is_derived_map[2] = return_true
+        SCons.Node._is_derived_map[3] = return_false
 
         f1 = self.fs.File('f1')
         f2 = self.fs.File('f2')
@@ -2978,19 +2998,19 @@ class RepositoryTestCase(_tempdirTestCase):
         assert r == os.path.join(self.rep3, 'f3'), r
 
         e1 = self.fs.File('e1')
-        e1.exists = return_false
+        e1._func_exists = 6
         e2 = self.fs.File('e2')
-        e2.exists = return_false
+        e2._func_exists = 6
 
         # Make sure we match entries in repositories,
         # regardless of whether they're derived or not.
 
         re1 = self.fs.Entry(os.path.join(self.rep1, 'e1'))
-        re1.exists = return_true
-        re1.is_derived = return_true
+        re1._func_exists = 5
+        re1._func_is_derived = 2
         re2 = self.fs.Entry(os.path.join(self.rep2, 'e2'))
-        re2.exists = return_true
-        re2.is_derived = return_false
+        re2._func_exists = 5
+        re2._func_is_derived = 3
 
         r = e1.rfile()
         assert r is re1, r
@@ -3244,9 +3264,13 @@ class stored_infoTestCase(unittest.TestCase):
                     self.xyzzy = 7
             def get_entry(self, name):
                 return self.Null()
+            
+        def test_sconsign(node):
+            return MySConsign()
 
         f = fs.File('file2', d)
-        f.dir.sconsign = MySConsign
+        SCons.Node.FS._sconsign_map[2] = test_sconsign
+        f.dir._func_sconsign = 2
         bi = f.get_stored_info()
         assert bi.xyzzy == 7, bi
 
@@ -3360,7 +3384,7 @@ class prepareTestCase(unittest.TestCase):
 
         xyz.set_state(0)
         xyz.prepare()
-        assert dir_made[0].path == "new_dir", dir_made[0]
+        assert dir_made[0].get_internal_path() == "new_dir", dir_made[0]
 
         dir = fs.Dir("dir")
         dir.prepare()
@@ -3373,7 +3397,7 @@ class SConstruct_dirTestCase(unittest.TestCase):
 
         fs = SCons.Node.FS.FS()
         fs.set_SConstruct_dir(fs.Dir('xxx'))
-        assert fs.SConstruct_dir.path == 'xxx'
+        assert fs.SConstruct_dir.get_internal_path() == 'xxx'
 
 
 
@@ -3552,7 +3576,7 @@ class SpecialAttrTestCase(unittest.TestCase):
         for_sig = f.suffix.for_signature()
         assert for_sig == 'baz.blat_suffix', for_sig
 
-        s = str(f.abspath)
+        s = str(f.get_abspath())
         assert s == test.workpath('work', 'foo', 'bar', 'baz.blat'), s
         assert f.abspath.is_literal(), f.abspath
         for_sig = f.abspath.for_signature()
diff --git a/src/engine/SCons/Node/NodeTests.py b/src/engine/SCons/Node/NodeTests.py
index 422d905..3a896ce 100644
--- a/src/engine/SCons/Node/NodeTests.py
+++ b/src/engine/SCons/Node/NodeTests.py
@@ -20,7 +20,7 @@
 # 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/Node/NodeTests.py rel_2.3.5:3347:d31d5a4e74b6 2015/07/31 14:36:10 bdbaddog"
+__revision__ = "src/engine/SCons/Node/NodeTests.py rel_2.4.0:3365:9259ea1c13d7 2015/09/21 14:03:43 bdbaddog"
 
 import SCons.compat
 
@@ -184,7 +184,7 @@ class Scanner(object):
     called = None
     def __call__(self, node):
         self.called = 1
-        return node.found_includes
+        return node.GetTag('found_includes')
     def path(self, env, dir, target=None, source=None):
         return ()
     def select(self, node):
@@ -200,7 +200,7 @@ class MyNode(SCons.Node.Node):
     def __init__(self, name):
         SCons.Node.Node.__init__(self)
         self.name = name
-        self.found_includes = []
+        self.Tag('found_includes', [])
     def __str__(self):
         return self.name
     def get_found_includes(self, env, scanner, target):
@@ -224,11 +224,18 @@ class Calculator(object):
 
 
 class NodeInfoBaseTestCase(unittest.TestCase):
+    # The abstract class NodeInfoBase has not enough default slots to perform
+    # the merge and format test (arbitrary attributes do not work). Do it with a
+    # derived class that does provide the slots.
 
     def test_merge(self):
         """Test merging NodeInfoBase attributes"""
-        ni1 = SCons.Node.NodeInfoBase(SCons.Node.Node())
-        ni2 = SCons.Node.NodeInfoBase(SCons.Node.Node())
+
+        class TestNodeInfo(SCons.Node.NodeInfoBase):
+            __slots__ = ('a1', 'a2', 'a3')
+
+        ni1 = TestNodeInfo()
+        ni2 = TestNodeInfo()
 
         ni1.a1 = 1
         ni1.a2 = 2
@@ -237,27 +244,32 @@ class NodeInfoBaseTestCase(unittest.TestCase):
         ni2.a3 = 333
 
         ni1.merge(ni2)
-        expect = {'a1':1, 'a2':222, 'a3':333, '_version_id':1}
-        assert ni1.__dict__ == expect, ni1.__dict__
+        assert ni1.a1 == 1, ni1.a1
+        assert ni1.a2 == 222, ni1.a2
+        assert ni1.a3 == 333, ni1.a3
 
     def test_update(self):
         """Test the update() method"""
-        ni = SCons.Node.NodeInfoBase(SCons.Node.Node())
+        ni = SCons.Node.NodeInfoBase()
         ni.update(SCons.Node.Node())
 
     def test_format(self):
         """Test the NodeInfoBase.format() method"""
-        ni1 = SCons.Node.NodeInfoBase(SCons.Node.Node())
+
+        class TestNodeInfo(SCons.Node.NodeInfoBase):
+            __slots__ = ('xxx', 'yyy', 'zzz')
+
+        ni1 = TestNodeInfo()
         ni1.xxx = 'x'
         ni1.yyy = 'y'
         ni1.zzz = 'z'
 
         f = ni1.format()
-        assert f == ['1', 'x', 'y', 'z'], f
+        assert f == ['x', 'y', 'z'], f
+ 
+        field_list = ['xxx', 'zzz', 'aaa']
 
-        ni1.field_list = ['xxx', 'zzz', 'aaa']
-
-        f = ni1.format()
+        f = ni1.format(field_list)
         assert f == ['x', 'z', 'None'], f
 
 
@@ -267,26 +279,26 @@ class BuildInfoBaseTestCase(unittest.TestCase):
     def test___init__(self):
         """Test BuildInfoBase initialization"""
         n = SCons.Node.Node()
-        bi = SCons.Node.BuildInfoBase(n)
+        bi = SCons.Node.BuildInfoBase()
         assert bi
 
     def test_merge(self):
         """Test merging BuildInfoBase attributes"""
         n1 = SCons.Node.Node()
-        bi1 = SCons.Node.BuildInfoBase(n1)
+        bi1 = SCons.Node.BuildInfoBase()
         n2 = SCons.Node.Node()
-        bi2 = SCons.Node.BuildInfoBase(n2)
+        bi2 = SCons.Node.BuildInfoBase()
 
-        bi1.a1 = 1
-        bi1.a2 = 2
+        bi1.bsources = 1
+        bi1.bdepends = 2
 
-        bi2.a2 = 222
-        bi2.a3 = 333
+        bi2.bdepends = 222
+        bi2.bact = 333
 
         bi1.merge(bi2)
-        assert bi1.a1 == 1, bi1.a1
-        assert bi1.a2 == 222, bi1.a2
-        assert bi1.a3 == 333, bi1.a3
+        assert bi1.bsources == 1, bi1.bsources
+        assert bi1.bdepends == 222, bi1.bdepends
+        assert bi1.bact == 333, bi1.bact
 
 
 class NodeTestCase(unittest.TestCase):
@@ -427,6 +439,7 @@ class NodeTestCase(unittest.TestCase):
     def test_built(self):
         """Test the built() method"""
         class SubNodeInfo(SCons.Node.NodeInfoBase):
+            __slots__ = ('updated',)
             def update(self, node):
                 self.updated = 1
         class SubNode(SCons.Node.Node):
@@ -434,7 +447,7 @@ class NodeTestCase(unittest.TestCase):
                 self.cleared = 1
 
         n = SubNode()
-        n.ninfo = SubNodeInfo(n)
+        n.ninfo = SubNodeInfo()
         n.built()
         assert n.cleared, n.cleared
         assert n.ninfo.updated, n.ninfo.cleared
@@ -568,32 +581,56 @@ class NodeTestCase(unittest.TestCase):
     def test_get_csig(self):
         """Test generic content signature calculation
         """
-        node = SCons.Node.Node()
-        node.get_contents = lambda: 444
-        result = node.get_csig()
-        assert result == '550a141f12de6341fba65b0ad0433500', result
+        
+        class TestNodeInfo(SCons.Node.NodeInfoBase):
+            __slots__ = ('csig',)
+        try:
+            SCons.Node.Node.NodeInfo = TestNodeInfo
+            def my_contents(obj):
+                return 444
+            SCons.Node._get_contents_map[4] = my_contents
+            node = SCons.Node.Node()
+            node._func_get_contents = 4
+            result = node.get_csig()
+            assert result == '550a141f12de6341fba65b0ad0433500', result
+        finally:
+            SCons.Node.Node.NodeInfo = SCons.Node.NodeInfoBase
 
     def test_get_cachedir_csig(self):
         """Test content signature calculation for CacheDir
         """
-        node = SCons.Node.Node()
-        node.get_contents = lambda: 555
-        result = node.get_cachedir_csig()
-        assert result == '15de21c670ae7c3f6f3f1f37029303c9', result
+        class TestNodeInfo(SCons.Node.NodeInfoBase):
+            __slots__ = ('csig',)
+        try:
+            SCons.Node.Node.NodeInfo = TestNodeInfo
+            def my_contents(obj):
+                return 555
+            SCons.Node._get_contents_map[4] = my_contents
+            node = SCons.Node.Node()
+            node._func_get_contents = 4
+            result = node.get_cachedir_csig()
+            assert result == '15de21c670ae7c3f6f3f1f37029303c9', result
+        finally:
+            SCons.Node.Node.NodeInfo = SCons.Node.NodeInfoBase
 
     def test_get_binfo(self):
         """Test fetching/creating a build information structure
         """
+        class TestNodeInfo(SCons.Node.NodeInfoBase):
+            __slots__ = ('csig',)
+        SCons.Node.Node.NodeInfo = TestNodeInfo
         node = SCons.Node.Node()
-
+ 
         binfo = node.get_binfo()
         assert isinstance(binfo, SCons.Node.BuildInfoBase), binfo
 
         node = SCons.Node.Node()
         d = SCons.Node.Node()
-        d.get_ninfo().csig = 777
+        ninfo = d.get_ninfo()
+        assert isinstance(ninfo, SCons.Node.NodeInfoBase), ninfo
         i = SCons.Node.Node()
-        i.get_ninfo().csig = 888
+        ninfo = i.get_ninfo()
+        assert isinstance(ninfo, SCons.Node.NodeInfoBase), ninfo
         node.depends = [d]
         node.implicit = [i]
 
@@ -655,7 +692,7 @@ class NodeTestCase(unittest.TestCase):
         """Test calling the method to store build information
         """
         node = SCons.Node.Node()
-        node.store_info()
+        SCons.Node.store_info_map[node.store_info](node)
 
     def test_get_stored_info(self):
         """Test calling the method to fetch stored build information
@@ -888,7 +925,7 @@ class NodeTestCase(unittest.TestCase):
         s = Scanner()
         d1 = MyNode("d1")
         d2 = MyNode("d2")
-        node.found_includes = [d1, d2]
+        node.Tag('found_includes', [d1, d2])
 
         # Simple return of the found includes
         deps = node.get_implicit_deps(env, s, target)
@@ -898,14 +935,14 @@ class NodeTestCase(unittest.TestCase):
         e = MyNode("eee")
         f = MyNode("fff")
         g = MyNode("ggg")
-        d1.found_includes = [e, f]
-        d2.found_includes = [e, f]
-        f.found_includes = [g]
+        d1.Tag('found_includes', [e, f])
+        d2.Tag('found_includes', [e, f])
+        f.Tag('found_includes', [g])
         deps = node.get_implicit_deps(env, s, target)
         assert deps == [d1, d2, e, f, g], list(map(str, deps))
 
         # Recursive scanning eliminates duplicates
-        e.found_includes = [f]
+        e.Tag('found_includes', [f])
         deps = node.get_implicit_deps(env, s, target)
         assert deps == [d1, d2, e, f, g], list(map(str, deps))
 
@@ -994,7 +1031,7 @@ class NodeTestCase(unittest.TestCase):
 
         s = Scanner()
         d = MyNode("ddd")
-        node.found_includes = [d]
+        node.Tag('found_includes', [d])
 
         node.builder.target_scanner = s
         assert node.implicit is None
@@ -1207,7 +1244,7 @@ class NodeTestCase(unittest.TestCase):
     def test_Annotate(self):
         """Test using an interface-specific Annotate function."""
         def my_annotate(node, self=self):
-            node.annotation = self.node_string
+            node.Tag('annotation', self.node_string)
 
         save_Annotate = SCons.Node.Annotate
         SCons.Node.Annotate = my_annotate
@@ -1215,11 +1252,13 @@ class NodeTestCase(unittest.TestCase):
         try:
             self.node_string = '#1'
             n = SCons.Node.Node()
-            assert n.annotation == '#1', n.annotation
+            a = n.GetTag('annotation')
+            assert a == '#1', a
 
             self.node_string = '#2'
             n = SCons.Node.Node()
-            assert n.annotation == '#2', n.annotation
+            a = n.GetTag('annotation')
+            assert a == '#2', a
         finally:
             SCons.Node.Annotate = save_Annotate
 
@@ -1230,7 +1269,7 @@ class NodeTestCase(unittest.TestCase):
         n.set_state(3)
         n.binfo = 'xyz'
         n.includes = 'testincludes'
-        n.found_include = {'testkey':'testvalue'}
+        n.Tag('found_includes', {'testkey':'testvalue'})
         n.implicit = 'testimplicit'
 
         x = MyExecutor()
diff --git a/src/engine/SCons/Node/Python.py b/src/engine/SCons/Node/Python.py
index 99773ab..b247ff6 100644
--- a/src/engine/SCons/Node/Python.py
+++ b/src/engine/SCons/Node/Python.py
@@ -27,20 +27,54 @@ Python nodes.
 # WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 #
 
-__revision__ = "src/engine/SCons/Node/Python.py rel_2.3.5:3347:d31d5a4e74b6 2015/07/31 14:36:10 bdbaddog"
+__revision__ = "src/engine/SCons/Node/Python.py rel_2.4.0:3365:9259ea1c13d7 2015/09/21 14:03:43 bdbaddog"
 
 import SCons.Node
 
 class ValueNodeInfo(SCons.Node.NodeInfoBase):
-    current_version_id = 1
+    __slots__ = ('csig',)
+    current_version_id = 2
 
     field_list = ['csig']
 
     def str_to_node(self, s):
         return Value(s)
 
+    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)
+
+
 class ValueBuildInfo(SCons.Node.BuildInfoBase):
-    current_version_id = 1
+    __slots__ = ()
+    current_version_id = 2
 
 class Value(SCons.Node.Node):
     """A class for Python variables, typically passed on the command line 
@@ -53,6 +87,8 @@ class Value(SCons.Node.Node):
     def __init__(self, value, built_value=None):
         SCons.Node.Node.__init__(self)
         self.value = value
+        self.changed_since_last_build = 6
+        self.store_info = 0
         if built_value is not None:
             self.built_value = built_value
 
diff --git a/src/engine/SCons/Node/PythonTests.py b/src/engine/SCons/Node/PythonTests.py
index 9544382..7163b91 100644
--- a/src/engine/SCons/Node/PythonTests.py
+++ b/src/engine/SCons/Node/PythonTests.py
@@ -21,7 +21,7 @@
 # WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 #
 
-__revision__ = "src/engine/SCons/Node/PythonTests.py rel_2.3.5:3347:d31d5a4e74b6 2015/07/31 14:36:10 bdbaddog"
+__revision__ = "src/engine/SCons/Node/PythonTests.py rel_2.4.0:3365:9259ea1c13d7 2015/09/21 14:03:43 bdbaddog"
 
 import sys
 import unittest
@@ -104,13 +104,13 @@ class ValueNodeInfoTestCase(unittest.TestCase):
     def test___init__(self):
         """Test ValueNodeInfo initialization"""
         vvv = SCons.Node.Python.Value('vvv')
-        ni = SCons.Node.Python.ValueNodeInfo(vvv)
+        ni = SCons.Node.Python.ValueNodeInfo()
 
 class ValueBuildInfoTestCase(unittest.TestCase):
     def test___init__(self):
         """Test ValueBuildInfo initialization"""
         vvv = SCons.Node.Python.Value('vvv')
-        bi = SCons.Node.Python.ValueBuildInfo(vvv)
+        bi = SCons.Node.Python.ValueBuildInfo()
 
 if __name__ == "__main__":
     suite = unittest.TestSuite()
diff --git a/src/engine/SCons/Node/__init__.py b/src/engine/SCons/Node/__init__.py
index a261ee7..79db894 100644
--- a/src/engine/SCons/Node/__init__.py
+++ b/src/engine/SCons/Node/__init__.py
@@ -41,7 +41,7 @@ be able to depend on any other type of "thing."
 # 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/Node/__init__.py rel_2.3.5:3347:d31d5a4e74b6 2015/07/31 14:36:10 bdbaddog"
+__revision__ = "src/engine/SCons/Node/__init__.py rel_2.4.0:3365:9259ea1c13d7 2015/09/21 14:03:43 bdbaddog"
 
 import collections
 import copy
@@ -55,6 +55,8 @@ import SCons.Util
 
 from SCons.Debug import Trace
 
+print_duplicate = 0
+
 def classname(obj):
     return str(obj.__class__).split('.')[-1]
 
@@ -105,6 +107,233 @@ Annotate = do_nothing
 # clean builds and update runs (see release_target_info).
 interactive = False
 
+def is_derived_none(node):
+    raise NotImplementedError
+
+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}
+
+def exists_none(node):
+    raise NotImplementedError
+
+def exists_always(node):
+    return 1
+
+def exists_base(node):
+    return node.stat() is not None
+
+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)
+
+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"%self
+                    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}
+
+
+def rexists_none(node):
+    raise NotImplementedError
+
+def rexists_node(node):
+    return node.exists()
+
+def rexists_base(node):
+    return node.rfile().exists()
+
+_rexists_map = {0 : rexists_none,
+                1 : rexists_node,
+                2 : rexists_base}
+
+def get_contents_none(node):
+    raise NotImplementedError
+
+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)
+
+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)
+
+def get_contents_file(node):    
+    if not node.rexists():
+        return ''
+    fname = node.rfile().get_abspath()
+    try:
+        contents = open(fname, "rb").read()
+    except EnvironmentError, 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}
+
+def target_from_source_none(node, prefix, suffix, splitext):
+    raise NotImplementedError
+
+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
+#
+def changed_since_last_build_node(node, target, prev_ni):
+    """
+
+    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
+
+def changed_since_last_build_alias(node, target, prev_ni):
+    cur_csig = node.get_csig()
+    try:
+        return cur_csig != prev_ni.csig
+    except AttributeError:
+        return 1
+
+def changed_since_last_build_entry(node, target, prev_ni):
+    node.disambiguate()
+    return _decider_map[node.changed_since_last_build](node, target, prev_ni)
+
+def changed_since_last_build_state_changed(node, target, prev_ni):
+    return (node.state != SCons.Node.up_to_date)
+
+def decide_source(node, target, prev_ni):
+    return target.get_build_env().decide_source(node, target, prev_ni)
+
+def decide_target(node, target, prev_ni):
+    return target.get_build_env().decide_target(node, target, prev_ni)
+
+def changed_since_last_build_python(node, target, prev_ni):
+    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
+#
+
+def store_info_pass(node):
+    pass
+
+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.
 
 class NodeInfoBase(object):
@@ -114,11 +343,8 @@ class NodeInfoBase(object):
     Node subclasses should subclass NodeInfoBase to provide their own
     logic for dealing with their own Node-specific signature information.
     """
-    current_version_id = 1
-    def __init__(self, node=None):
-        # Create an object attribute from the class attribute so it ends up
-        # in the pickled data in the .sconsign file.
-        self._version_id = self.current_version_id
+    __slots__ = ('__weakref__',)
+    current_version_id = 2
     def update(self, node):
         try:
             field_list = self.field_list
@@ -138,13 +364,25 @@ class NodeInfoBase(object):
     def convert(self, node, val):
         pass
     def merge(self, other):
-        self.__dict__.update(other.__dict__)
+        """
+        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 format(self, field_list=None, names=0):
         if field_list is None:
             try:
                 field_list = self.field_list
             except AttributeError:
-                field_list = sorted(self.__dict__.keys())
+                field_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:
@@ -157,6 +395,38 @@ class NodeInfoBase(object):
             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)
+
+
 class BuildInfoBase(object):
     """
     The generic base class for build information for a Node.
@@ -167,30 +437,106 @@ class BuildInfoBase(object):
     generic build stuff we have to track:  sources, explicit dependencies,
     implicit dependencies, and action information.
     """
-    current_version_id = 1
-    def __init__(self, node=None):
+    __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._version_id = self.current_version_id
         self.bsourcesigs = []
         self.bdependsigs = []
         self.bimplicitsigs = []
         self.bactsig = None
     def merge(self, other):
-        self.__dict__.update(other.__dict__)
+        """
+        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)
 
 class Node(object):
     """The base Node class, for entities that we know how to
     build, or use to build other Nodes.
     """
 
-    if SCons.Memoize.use_memoizer:
-        __metaclass__ = SCons.Memoize.Memoized_Metaclass
-
-    memoizer_counters = []
+    __slots__ = ['sources',
+                 'sources_set',
+                 '_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']
 
     class Attrs(object):
-        pass
+        __slots__ = ('shared', '__dict__')
+ 
 
     def __init__(self):
         if SCons.Debug.track_instances: logInstanceCreation(self, 'Node.Node')
@@ -234,7 +580,15 @@ class Node(object):
         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.clear_memoized_values()
 
         # Let the interface in which the build engine is embedded
@@ -248,8 +602,7 @@ class Node(object):
     def get_suffix(self):
         return ''
 
-    memoizer_counters.append(SCons.Memoize.CountValue('get_build_env'))
-
+    @SCons.Memoize.CountMethodCall
     def get_build_env(self):
         """Fetch the appropriate Environment to build this node.
         """
@@ -418,7 +771,7 @@ class Node(object):
             pass
         else:
             self.ninfo.update(self)
-            self.store_info()
+            SCons.Node.store_info_map[self.store_info](self)
 
     def release_target_info(self):
         """Called just after this node has been marked
@@ -546,7 +899,7 @@ class Node(object):
         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
+        return _is_derived_map[self._func_is_derived](self)
 
     def alter_targets(self):
         """Return a list of alternate targets for this Node.
@@ -706,7 +1059,7 @@ class Node(object):
     BuildInfo = BuildInfoBase
 
     def new_ninfo(self):
-        ninfo = self.NodeInfo(self)
+        ninfo = self.NodeInfo()
         return ninfo
 
     def get_ninfo(self):
@@ -717,7 +1070,7 @@ class Node(object):
             return self.ninfo
 
     def new_binfo(self):
-        binfo = self.BuildInfo(self)
+        binfo = self.BuildInfo()
         return binfo
 
     def get_binfo(self):
@@ -802,14 +1155,6 @@ class Node(object):
     def get_cachedir_csig(self):
         return self.get_csig()
 
-    def store_info(self):
-        """Make the build signature permanent (that is, store it in the
-        .sconsign file or equivalent)."""
-        pass
-
-    def do_not_store_info(self):
-        pass
-
     def get_stored_info(self):
         return None
 
@@ -847,13 +1192,16 @@ class Node(object):
 
     def exists(self):
         """Does this node exists?"""
-        # All node exist by default:
-        return 1
+        return _exists_map[self._func_exists](self)
 
     def rexists(self):
         """Does this node exist locally or in a repositiory?"""
         # There are no repositories by default:
-        return self.exists()
+        return _rexists_map[self._func_rexists](self)
+
+    def get_contents(self):
+        """Fetch the contents of the entry."""
+        return _get_contents_map[self._func_get_contents](self)
 
     def missing(self):
         return not self.is_derived() and \
@@ -941,11 +1289,10 @@ class Node(object):
         # build info that it's cached so we can re-calculate it.
         self.executor_cleanup()
 
-    memoizer_counters.append(SCons.Memoize.CountValue('_children_get'))
-
+    @SCons.Memoize.CountMethodCall
     def _children_get(self):
         try:
-            return self._memo['children_get']
+            return self._memo['_children_get']
         except KeyError:
             pass
 
@@ -976,7 +1323,7 @@ class Node(object):
         else:
             children = self.all_children(scan=0)
 
-        self._memo['children_get'] = children
+        self._memo['_children_get'] = children
         return children
 
     def all_children(self, scan=1):
@@ -1016,9 +1363,6 @@ class Node(object):
     def get_state(self):
         return self.state
 
-    def state_has_changed(self, target, prev_ni):
-        return (self.state != SCons.Node.up_to_date)
-
     def get_env(self):
         env = self.env
         if not env:
@@ -1026,28 +1370,28 @@ class Node(object):
             env = SCons.Defaults.DefaultEnvironment()
         return env
 
-    def changed_since_last_build(self, target, prev_ni):
-        """
-
-        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
-
     def Decider(self, function):
-        SCons.Util.AddMethod(self, function, 'changed_since_last_build')
+        foundkey = None
+        for k, v in _decider_map.iteritems():
+            if v == function:
+                foundkey = k
+                break
+        if not foundkey:
+            foundkey = len(_decider_map)
+            _decider_map[foundkey] = function
+        self.changed_since_last_build = foundkey
+
+    def Tag(self, key, value):
+        """ Add a user-defined tag. """
+        if not self._tags:
+            self._tags = {}
+        self._tags[key] = value
+
+    def GetTag(self, key):
+        """ Return a user-defined tag. """
+        if not self._tags:
+            return None
+        return self._tags.get(key, None)
 
     def changed(self, node=None, allowcache=False):
         """
@@ -1095,7 +1439,7 @@ class Node(object):
             result = True
 
         for child, prev_ni in zip(children, then):
-            if child.changed_since_last_build(self, prev_ni):
+            if _decider_map[child.changed_since_last_build](child, self, prev_ni):
                 if t: Trace(': %s changed' % child)
                 result = True
 
@@ -1266,7 +1610,7 @@ class Node(object):
         for k in new_bkids:
             if not k in old_bkids:
                 lines.append("`%s' is a new dependency\n" % stringify(k))
-            elif k.changed_since_last_build(self, osig[k]):
+            elif _decider_map[k.changed_since_last_build](k, self, osig[k]):
                 lines.append("`%s' changed\n" % stringify(k))
 
         if len(lines) == 0 and old_bkids != new_bkids: