/couchjs/scons/scons-local-2.0.1/SCons/Node/FS.py

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"""scons.Node.FS

File system nodes.

These Nodes represent the canonical external objects that people think
of when they think of building software: files and directories.

This holds a "default_fs" variable that should be initialized with an FS
that can be used by scripts or modules looking for the canonical default.

"""

#
# Copyright (c) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010 The SCons Foundation
#
# Permission is hereby granted, free of charge, to any person obtaining
# a copy of this software and associated documentation files (the
# "Software"), to deal in the Software without restriction, including
# without limitation the rights to use, copy, modify, merge, publish,
# distribute, sublicense, and/or sell copies of the Software, and to
# permit persons to whom the Software is furnished to do so, subject to
# the following conditions:
#
# The above copyright notice and this permission notice shall be included
# in all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY
# KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
# WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
# LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
# OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

__revision__ = "src/engine/SCons/Node/FS.py 5134 2010/08/16 23:02:40 bdeegan"

import fnmatch
import os
import re
import shutil
import stat
import sys
import time
import codecs

import SCons.Action
from SCons.Debug import logInstanceCreation
import SCons.Errors
import SCons.Memoize
import SCons.Node
import SCons.Node.Alias
import SCons.Subst
import SCons.Util
import SCons.Warnings

from SCons.Debug import Trace

do_store_info = True


class EntryProxyAttributeError(AttributeError):
    """
    An AttributeError subclass for recording and displaying the name
    of the underlying Entry involved in an AttributeError exception.
    """
    def __init__(self, entry_proxy, attribute):
        AttributeError.__init__(self)
        self.entry_proxy = entry_proxy
        self.attribute = attribute
    def __str__(self):
        entry = self.entry_proxy.get()
        fmt = "%s instance %s has no attribute %s"
        return fmt % (entry.__class__.__name__,
                      repr(entry.name),
                      repr(self.attribute))

# The max_drift value:  by default, use a cached signature value for
# any file that's been untouched for more than two days.
default_max_drift = 2*24*60*60

#
# We stringify these file system Nodes a lot.  Turning a file system Node
# into a string is non-trivial, because the final string representation
# can depend on a lot of factors:  whether it's a derived target or not,
# whether it's linked to a repository or source directory, and whether
# there's duplication going on.  The normal technique for optimizing
# calculations like this is to memoize (cache) the string value, so you
# only have to do the calculation once.
#
# A number of the above factors, however, can be set after we've already
# been asked to return a string for a Node, because a Repository() or
# VariantDir() call or the like may not occur until later in SConscript
# files.  So this variable controls whether we bother trying to save
# string values for Nodes.  The wrapper interface can set this whenever
# they're done mucking with Repository and VariantDir and the other stuff,
# to let this module know it can start returning saved string values
# for Nodes.
#
Save_Strings = None

def save_strings(val):
    global Save_Strings
    Save_Strings = val

#
# Avoid unnecessary function calls by recording a Boolean value that
# tells us whether or not os.path.splitdrive() actually does anything
# on this system, and therefore whether we need to bother calling it
# when looking up path names in various methods below.
# 

do_splitdrive = None

def initialize_do_splitdrive():
    global do_splitdrive
    drive, path = os.path.splitdrive('X:/foo')
    do_splitdrive = not not drive

initialize_do_splitdrive()

#

needs_normpath_check = None

def initialize_normpath_check():
    """
    Initialize the normpath_check regular expression.

    This function is used by the unit tests to re-initialize the pattern
    when testing for behavior with different values of os.sep.
    """
    global needs_normpath_check
    if os.sep == '/':
        pattern = r'.*/|\.$|\.\.$'
    else:
        pattern = r'.*[/%s]|\.$|\.\.$' % re.escape(os.sep)
    needs_normpath_check = re.compile(pattern)

initialize_normpath_check()

#
# SCons.Action objects for interacting with the outside world.
#
# The Node.FS methods in this module should use these actions to
# create and/or remove files and directories; they should *not* use
# os.{link,symlink,unlink,mkdir}(), etc., directly.
#
# Using these SCons.Action objects ensures that descriptions of these
# external activities are properly displayed, that the displays are
# suppressed when the -s (silent) option is used, and (most importantly)
# the actions are disabled when the the -n option is used, in which case
# there should be *no* changes to the external file system(s)...
#

if hasattr(os, 'link'):
    def _hardlink_func(fs, src, dst):
        # If the source is a symlink, we can't just hard-link to it
        # because a relative symlink may point somewhere completely
        # different.  We must disambiguate the symlink and then
        # hard-link the final destination file.
        while fs.islink(src):
            link = fs.readlink(src)
            if not os.path.isabs(link):
                src = link
            else:
                src = os.path.join(os.path.dirname(src), link)
        fs.link(src, dst)
else:
    _hardlink_func = None

if hasattr(os, 'symlink'):
    def _softlink_func(fs, src, dst):
        fs.symlink(src, dst)
else:
    _softlink_func = None

def _copy_func(fs, src, dest):
    shutil.copy2(src, dest)
    st = fs.stat(src)
    fs.chmod(dest, stat.S_IMODE(st[stat.ST_MODE]) | stat.S_IWRITE)


Valid_Duplicates = ['hard-soft-copy', 'soft-hard-copy',
                    'hard-copy', 'soft-copy', 'copy']

Link_Funcs = [] # contains the callables of the specified duplication style

def set_duplicate(duplicate):
    # Fill in the Link_Funcs list according to the argument
    # (discarding those not available on the platform).

    # Set up the dictionary that maps the argument names to the
    # underlying implementations.  We do this inside this function,
    # not in the top-level module code, so that we can remap os.link
    # and os.symlink for testing purposes.
    link_dict = {
        'hard' : _hardlink_func,
        'soft' : _softlink_func,
        'copy' : _copy_func
    }

    if not duplicate in Valid_Duplicates:
        raise SCons.Errors.InternalError("The argument of set_duplicate "
                                           "should be in Valid_Duplicates")
    global Link_Funcs
    Link_Funcs = []
    for func in duplicate.split('-'):
        if link_dict[func]:
            Link_Funcs.append(link_dict[func])

def LinkFunc(target, source, env):
    # Relative paths cause problems with symbolic links, so
    # we use absolute paths, which may be a problem for people
    # 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
    dir, file = os.path.split(dest)
    if dir and not target[0].fs.isdir(dir):
        os.makedirs(dir)
    if not Link_Funcs:
        # Set a default order of link functions.
        set_duplicate('hard-soft-copy')
    fs = source[0].fs
    # Now link the files with the previously specified order.
    for func in Link_Funcs:
        try:
            func(fs, src, dest)
            break
        except (IOError, OSError):
            # An OSError indicates something happened like a permissions
            # problem or an attempt to symlink across file-system
            # boundaries.  An IOError indicates something like the file
            # not existing.  In either case, keeping trying additional
            # functions in the list and only raise an error if the last
            # one failed.
            if func == Link_Funcs[-1]:
                # exception of the last link method (copy) are fatal
                raise
    return 0

Link = SCons.Action.Action(LinkFunc, None)
def LocalString(target, source, env):
    return 'Local copy of %s from %s' % (target[0], source[0])

LocalCopy = SCons.Action.Action(LinkFunc, LocalString)

def UnlinkFunc(target, source, env):
    t = target[0]
    t.fs.unlink(t.abspath)
    return 0

Unlink = SCons.Action.Action(UnlinkFunc, None)

def MkdirFunc(target, source, env):
    t = target[0]
    if not t.exists():
        t.fs.mkdir(t.abspath)
    return 0

Mkdir = SCons.Action.Action(MkdirFunc, None, presub=None)

MkdirBuilder = None

def get_MkdirBuilder():
    global MkdirBuilder
    if MkdirBuilder is None:
        import SCons.Builder
        import SCons.Defaults
        # "env" will get filled in by Executor.get_build_env()
        # calling SCons.Defaults.DefaultEnvironment() when necessary.
        MkdirBuilder = SCons.Builder.Builder(action = Mkdir,
                                             env = None,
                                             explain = None,
                                             is_explicit = None,
                                             target_scanner = SCons.Defaults.DirEntryScanner,
                                             name = "MkdirBuilder")
    return MkdirBuilder

class _Null(object):
    pass

_null = _Null()

DefaultSCCSBuilder = None
DefaultRCSBuilder = None

def get_DefaultSCCSBuilder():
    global DefaultSCCSBuilder
    if DefaultSCCSBuilder is None:
        import SCons.Builder
        # "env" will get filled in by Executor.get_build_env()
        # calling SCons.Defaults.DefaultEnvironment() when necessary.
        act = SCons.Action.Action('$SCCSCOM', '$SCCSCOMSTR')
        DefaultSCCSBuilder = SCons.Builder.Builder(action = act,
                                                   env = None,
                                                   name = "DefaultSCCSBuilder")
    return DefaultSCCSBuilder

def get_DefaultRCSBuilder():
    global DefaultRCSBuilder
    if DefaultRCSBuilder is None:
        import SCons.Builder
        # "env" will get filled in by Executor.get_build_env()
        # calling SCons.Defaults.DefaultEnvironment() when necessary.
        act = SCons.Action.Action('$RCS_COCOM', '$RCS_COCOMSTR')
        DefaultRCSBuilder = SCons.Builder.Builder(action = act,
                                                  env = None,
                                                  name = "DefaultRCSBuilder")
    return DefaultRCSBuilder

# Cygwin's os.path.normcase pretends it's on a case-sensitive filesystem.
_is_cygwin = sys.platform == "cygwin"
if os.path.normcase("TeSt") == os.path.normpath("TeSt") and not _is_cygwin:
    def _my_normcase(x):
        return x
else:
    def _my_normcase(x):
        return x.upper()



class DiskChecker(object):
    def __init__(self, type, do, ignore):
        self.type = type
        self.do = do
        self.ignore = ignore
        self.func = do
    def __call__(self, *args, **kw):
        return self.func(*args, **kw)
    def set(self, list):
        if self.type in list:
            self.func = self.do
        else:
            self.func = self.ignore

def do_diskcheck_match(node, predicate, errorfmt):
    result = predicate()
    try:
        # If calling the predicate() cached a None value from stat(),
        # remove it so it doesn't interfere with later attempts to
        # build this Node as we walk the DAG.  (This isn't a great way
        # to do this, we're reaching into an interface that doesn't
        # really belong to us, but it's all about performance, so
        # for now we'll just document the dependency...)
        if node._memo['stat'] is None:
            del node._memo['stat']
    except (AttributeError, KeyError):
        pass
    if result:
        raise TypeError(errorfmt % node.abspath)

def ignore_diskcheck_match(node, predicate, errorfmt):
    pass

def do_diskcheck_rcs(node, name):
    try:
        rcs_dir = node.rcs_dir
    except AttributeError:
        if node.entry_exists_on_disk('RCS'):
            rcs_dir = node.Dir('RCS')
        else:
            rcs_dir = None
        node.rcs_dir = rcs_dir
    if rcs_dir:
        return rcs_dir.entry_exists_on_disk(name+',v')
    return None

def ignore_diskcheck_rcs(node, name):
    return None

def do_diskcheck_sccs(node, name):
    try:
        sccs_dir = node.sccs_dir
    except AttributeError:
        if node.entry_exists_on_disk('SCCS'):
            sccs_dir = node.Dir('SCCS')
        else:
            sccs_dir = None
        node.sccs_dir = sccs_dir
    if sccs_dir:
        return sccs_dir.entry_exists_on_disk('s.'+name)
    return None

def ignore_diskcheck_sccs(node, name):
    return None

diskcheck_match = DiskChecker('match', do_diskcheck_match, ignore_diskcheck_match)
diskcheck_rcs = DiskChecker('rcs', do_diskcheck_rcs, ignore_diskcheck_rcs)
diskcheck_sccs = DiskChecker('sccs', do_diskcheck_sccs, ignore_diskcheck_sccs)

diskcheckers = [
    diskcheck_match,
    diskcheck_rcs,
    diskcheck_sccs,
]

def set_diskcheck(list):
    for dc in diskcheckers:
        dc.set(list)

def diskcheck_types():
    return [dc.type for dc in diskcheckers]



class EntryProxy(SCons.Util.Proxy):

    __str__ = SCons.Util.Delegate('__str__')

    def __get_abspath(self):
        entry = self.get()
        return SCons.Subst.SpecialAttrWrapper(entry.get_abspath(),
                                             entry.name + "_abspath")

    def __get_filebase(self):
        name = self.get().name
        return SCons.Subst.SpecialAttrWrapper(SCons.Util.splitext(name)[0],
                                             name + "_filebase")

    def __get_suffix(self):
        name = self.get().name
        return SCons.Subst.SpecialAttrWrapper(SCons.Util.splitext(name)[1],
                                             name + "_suffix")

    def __get_file(self):
        name = self.get().name
        return SCons.Subst.SpecialAttrWrapper(name, name + "_file")

    def __get_base_path(self):
        """Return the file's directory and file name, with the
        suffix stripped."""
        entry = self.get()
        return SCons.Subst.SpecialAttrWrapper(SCons.Util.splitext(entry.get_path())[0],
                                             entry.name + "_base")

    def __get_posix_path(self):
        """Return the path with / as the path separator,
        regardless of platform."""
        if os.sep == '/':
            return self
        else:
            entry = self.get()
            r = entry.get_path().replace(os.sep, '/')
            return SCons.Subst.SpecialAttrWrapper(r, entry.name + "_posix")

    def __get_windows_path(self):
        """Return the path with \ as the path separator,
        regardless of platform."""
        if os.sep == '\\':
            return self
        else:
            entry = self.get()
            r = entry.get_path().replace(os.sep, '\\')
            return SCons.Subst.SpecialAttrWrapper(r, entry.name + "_windows")

    def __get_srcnode(self):
        return EntryProxy(self.get().srcnode())

    def __get_srcdir(self):
        """Returns the directory containing the source node linked to this
        node via VariantDir(), or the directory of this node if not linked."""
        return EntryProxy(self.get().srcnode().dir)

    def __get_rsrcnode(self):
        return EntryProxy(self.get().srcnode().rfile())

    def __get_rsrcdir(self):
        """Returns the directory containing the source node linked to this
        node via VariantDir(), or the directory of this node if not linked."""
        return EntryProxy(self.get().srcnode().rfile().dir)

    def __get_dir(self):
        return EntryProxy(self.get().dir)

    dictSpecialAttrs = { "base"     : __get_base_path,
                         "posix"    : __get_posix_path,
                         "windows"  : __get_windows_path,
                         "win32"    : __get_windows_path,
                         "srcpath"  : __get_srcnode,
                         "srcdir"   : __get_srcdir,
                         "dir"      : __get_dir,
                         "abspath"  : __get_abspath,
                         "filebase" : __get_filebase,
                         "suffix"   : __get_suffix,
                         "file"     : __get_file,
                         "rsrcpath" : __get_rsrcnode,
                         "rsrcdir"  : __get_rsrcdir,
                       }

    def __getattr__(self, name):
        # This is how we implement the "special" attributes
        # such as base, posix, srcdir, etc.
        try:
            attr_function = self.dictSpecialAttrs[name]
        except KeyError:
            try:
                attr = SCons.Util.Proxy.__getattr__(self, name)
            except AttributeError, e:
                # Raise our own AttributeError subclass with an
                # overridden __str__() method that identifies the
                # name of the entry that caused the exception.
                raise EntryProxyAttributeError(self, name)
            return attr
        else:
            return attr_function(self)

class Base(SCons.Node.Node):
    """A generic class for file system entries.  This class is for
    when we don't know yet whether the entry being looked up is a file
    or a directory.  Instances of this class can morph into either
    Dir or File objects by a later, more precise lookup.

    Note: this class does not define __cmp__ and __hash__ for
    efficiency reasons.  SCons does a lot of comparing of
    Node.FS.{Base,Entry,File,Dir} objects, so those operations must be
    as fast as possible, which means we want to use Python's built-in
    object identity comparisons.
    """

    memoizer_counters = []

    def __init__(self, name, directory, fs):
        """Initialize a generic Node.FS.Base object.

        Call the superclass initialization, take care of setting up
        our relative and absolute paths, identify our parent
        directory, and indicate that this node should use
        signatures."""
        if __debug__: logInstanceCreation(self, 'Node.FS.Base')
        SCons.Node.Node.__init__(self)

        # Filenames and paths are probably reused and are intern'ed to
        # save some memory.
        self.name = SCons.Util.silent_intern(name)
        self.suffix = SCons.Util.silent_intern(SCons.Util.splitext(name)[1])
        self.fs = fs

        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.dir = directory
        self.cwd = None # will hold the SConscript directory for target nodes
        self.duplicate = directory.duplicate

    def str_for_display(self):
        return '"' + self.__str__() + '"'

    def must_be_same(self, klass):
        """
        This node, which already existed, is being looked up as the
        specified klass.  Raise an exception if it isn't.
        """
        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__))

    def get_dir(self):
        return self.dir

    def get_suffix(self):
        return self.suffix

    def rfile(self):
        return self

    def __str__(self):
        """A Node.FS.Base object's string representation is its path
        name."""
        global Save_Strings
        if Save_Strings:
            return self._save_str()
        return self._get_str()

    memoizer_counters.append(SCons.Memoize.CountValue('_save_str'))

    def _save_str(self):
        try:
            return self._memo['_save_str']
        except KeyError:
            pass
        result = sys.intern(self._get_str())
        self._memo['_save_str'] = result
        return result

    def _get_str(self):
        global Save_Strings
        if self.duplicate or self.is_derived():
            return self.get_path()
        srcnode = self.srcnode()
        if srcnode.stat() is None and self.stat() is not None:
            result = self.get_path()
        else:
            result = srcnode.get_path()
        if not Save_Strings:
            # We're not at the point where we're saving the string string
            # representations of FS Nodes (because we haven't finished
            # reading the SConscript files and need to have str() return
            # things relative to them).  That also means we can't yet
            # cache values returned (or not returned) by stat(), since
            # Python code in the SConscript files might still create
            # or otherwise affect the on-disk file.  So get rid of the
            # values that the underlying stat() method saved.
            try: del self._memo['stat']
            except KeyError: pass
            if self is not srcnode:
                try: del srcnode._memo['stat']
                except KeyError: pass
        return result

    rstr = __str__

    memoizer_counters.append(SCons.Memoize.CountValue('stat'))

    def stat(self):
        try: return self._memo['stat']
        except KeyError: pass
        try: result = self.fs.stat(self.abspath)
        except os.error: result = None
        self._memo['stat'] = result
        return result

    def exists(self):
        return self.stat() is not None

    def rexists(self):
        return self.rfile().exists()

    def getmtime(self):
        st = self.stat()
        if st: return st[stat.ST_MTIME]
        else: return None

    def getsize(self):
        st = self.stat()
        if st: return st[stat.ST_SIZE]
        else: return None

    def isdir(self):
        st = self.stat()
        return st is not None and stat.S_ISDIR(st[stat.ST_MODE])

    def isfile(self):
        st = self.stat()
        return st is not None and stat.S_ISREG(st[stat.ST_MODE])

    if hasattr(os, 'symlink'):
        def islink(self):
            try: st = self.fs.lstat(self.abspath)
            except os.error: return 0
            return stat.S_ISLNK(st[stat.ST_MODE])
    else:
        def islink(self):
            return 0                    # no symlinks

    def is_under(self, dir):
        if self is dir:
            return 1
        else:
            return self.dir.is_under(dir)

    def set_local(self):
        self._local = 1

    def srcnode(self):
        """If this node is in a build path, return the node
        corresponding to its source file.  Otherwise, return
        ourself.
        """
        srcdir_list = self.dir.srcdir_list()
        if srcdir_list:
            srcnode = srcdir_list[0].Entry(self.name)
            srcnode.must_be_same(self.__class__)
            return srcnode
        return self

    def get_path(self, dir=None):
        """Return path relative to the current working directory of the
        Node.FS.Base object that owns us."""
        if not dir:
            dir = self.fs.getcwd()
        if self == dir:
            return '.'
        path_elems = self.path_elements
        try: i = path_elems.index(dir)
        except ValueError: pass
        else: path_elems = path_elems[i+1:]
        path_elems = [n.name for n in path_elems]
        return os.sep.join(path_elems)

    def set_src_builder(self, builder):
        """Set the source code builder for this node."""
        self.sbuilder = builder
        if not self.has_builder():
            self.builder_set(builder)

    def src_builder(self):
        """Fetch the source code builder for this node.

        If there isn't one, we cache the source code builder specified
        for the directory (which in turn will cache the value from its
        parent directory, and so on up to the file system root).
        """
        try:
            scb = self.sbuilder
        except AttributeError:
            scb = self.dir.src_builder()
            self.sbuilder = scb
        return scb

    def get_abspath(self):
        """Get the absolute path of the file."""
        return self.abspath

    def for_signature(self):
        # Return just our name.  Even an absolute path would not work,
        # because that can change thanks to symlinks or remapped network
        # paths.
        return self.name

    def get_subst_proxy(self):
        try:
            return self._proxy
        except AttributeError:
            ret = EntryProxy(self)
            self._proxy = ret
            return ret

    def target_from_source(self, prefix, suffix, splitext=SCons.Util.splitext):
        """

        Generates a target entry that corresponds to this entry (usually
        a source file) with the specified prefix and suffix.

        Note that this method can be overridden dynamically for generated
        files that need different behavior.  See Tool/swig.py for
        an example.
        """
        return self.dir.Entry(prefix + splitext(self.name)[0] + suffix)

    def _Rfindalldirs_key(self, pathlist):
        return pathlist

    memoizer_counters.append(SCons.Memoize.CountDict('Rfindalldirs', _Rfindalldirs_key))

    def Rfindalldirs(self, pathlist):
        """
        Return all of the directories for a given path list, including
        corresponding "backing" directories in any repositories.

        The Node lookups are relative to this Node (typically a
        directory), so memoizing result saves cycles from looking
        up the same path for each target in a given directory.
        """
        try:
            memo_dict = self._memo['Rfindalldirs']
        except KeyError:
            memo_dict = {}
            self._memo['Rfindalldirs'] = memo_dict
        else:
            try:
                return memo_dict[pathlist]
            except KeyError:
                pass

        create_dir_relative_to_self = self.Dir
        result = []
        for path in pathlist:
            if isinstance(path, SCons.Node.Node):
                result.append(path)
            else:
                dir = create_dir_relative_to_self(path)
                result.extend(dir.get_all_rdirs())

        memo_dict[pathlist] = result

        return result

    def RDirs(self, pathlist):
        """Search for a list of directories in the Repository list."""
        cwd = self.cwd or self.fs._cwd
        return cwd.Rfindalldirs(pathlist)

    memoizer_counters.append(SCons.Memoize.CountValue('rentry'))

    def rentry(self):
        try:
            return self._memo['rentry']
        except KeyError:
            pass
        result = self
        if not self.exists():
            norm_name = _my_normcase(self.name)
            for dir in self.dir.get_all_rdirs():
                try:
                    node = dir.entries[norm_name]
                except KeyError:
                    if dir.entry_exists_on_disk(self.name):
                        result = dir.Entry(self.name)
                        break
        self._memo['rentry'] = result
        return result

    def _glob1(self, pattern, ondisk=True, source=False, strings=False):
        return []

class Entry(Base):
    """This is the class for generic Node.FS entries--that is, things
    that could be a File or a Dir, but we're just not sure yet.
    Consequently, the methods in this class really exist just to
    transform their associated object into the right class when the
    time comes, and then call the same-named method in the transformed
    class."""

    def diskcheck_match(self):
        pass

    def disambiguate(self, must_exist=None):
        """
        """
        if self.isdir():
            self.__class__ = Dir
            self._morph()
        elif self.isfile():
            self.__class__ = File
            self._morph()
            self.clear()
        else:
            # There was nothing on-disk at this location, so look in
            # the src directory.
            #
            # We can't just use self.srcnode() straight away because
            # that would create an actual Node for this file in the src
            # directory, and there might not be one.  Instead, use the
            # dir_on_disk() method to see if there's something on-disk
            # with that name, in which case we can go ahead and call
            # self.srcnode() to create the right type of entry.
            srcdir = self.dir.srcnode()
            if srcdir != self.dir and \
               srcdir.entry_exists_on_disk(self.name) and \
               self.srcnode().isdir():
                self.__class__ = Dir
                self._morph()
            elif must_exist:
                msg = "No such file or directory: '%s'" % self.abspath
                raise SCons.Errors.UserError(msg)
            else:
                self.__class__ = File
                self._morph()
                self.clear()
        return self

    def rfile(self):
        """We're a generic Entry, but the caller is actually looking for
        a File at this point, so morph into one."""
        self.__class__ = File
        self._morph()
        self.clear()
        return File.rfile(self)

    def scanner_key(self):
        return self.get_suffix()

    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()

    def get_text_contents(self):
        """Fetch the decoded text contents of a Unicode encoded Entry.

        Since this should return the text contents from the file
        system, we check to see into what sort of subclass we should
        morph this Entry."""
        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_text_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_text_contents()

    def must_be_same(self, klass):
        """Called to make sure a Node is a Dir.  Since we're an
        Entry, we can morph into one."""
        if self.__class__ is not klass:
            self.__class__ = klass
            self._morph()
            self.clear()

    # The following methods can get called before the Taskmaster has
    # had a chance to call disambiguate() directly to see if this Entry
    # should really be a Dir or a File.  We therefore use these to call
    # disambiguate() transparently (from our caller's point of view).
    #
    # Right now, this minimal set of methods has been derived by just
    # looking at some of the methods that will obviously be called early
    # in any of the various Taskmasters' calling sequences, and then
    # empirically figuring out which additional methods are necessary
    # 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()

    def rel_path(self, other):
        d = self.disambiguate()
        if d.__class__ is Entry:
            raise Exception("rel_path() could not disambiguate File/Dir")
        return d.rel_path(other)

    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)

    def get_subst_proxy(self):
        return self.disambiguate().get_subst_proxy()

# This is for later so we can differentiate between Entry the class and Entry
# the method of the FS class.
_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
    # anything with or to the local file system.
    #
    # Note that there's a very good chance we'll refactor this part of
    # the architecture in some way as we really implement the interface(s)
    # for remote file system Nodes.  For example, the right architecture
    # might be to have this be a subclass instead of a base class.
    # Nevertheless, we're using this as a first step in that direction.
    #
    # We're not using chdir() yet because the calling subclass method
    # needs to use os.chdir() directly to avoid recursion.  Will we
    # really need this one?
    #def chdir(self, path):
    #    return os.chdir(path)
    def chmod(self, path, mode):
        return os.chmod(path, mode)
    def copy(self, src, dst):
        return shutil.copy(src, dst)
    def copy2(self, src, dst):
        return shutil.copy2(src, dst)
    def exists(self, path):
        return os.path.exists(path)
    def getmtime(self, path):
        return os.path.getmtime(path)
    def getsize(self, path):
        return os.path.getsize(path)
    def isdir(self, path):
        return os.path.isdir(path)
    def isfile(self, path):
        return os.path.isfile(path)
    def link(self, src, dst):
        return os.link(src, dst)
    def lstat(self, path):
        return os.lstat(path)
    def listdir(self, path):
        return os.listdir(path)
    def makedirs(self, path):
        return os.makedirs(path)
    def mkdir(self, path):
        return os.mkdir(path)
    def rename(self, old, new):
        return os.rename(old, new)
    def stat(self, path):
        return os.stat(path)
    def symlink(self, src, dst):
        return os.symlink(src, dst)
    def open(self, path):
        return open(path)
    def unlink(self, path):
        return os.unlink(path)

    if hasattr(os, 'symlink'):
        def islink(self, path):
            return os.path.islink(path)
    else:
        def islink(self, path):
            return 0                    # no symlinks

    if hasattr(os, 'readlink'):
        def readlink(self, file):
            return os.readlink(file)
    else:
        def readlink(self, file):
            return ''


#class RemoteFS:
#    # Skeleton for the obvious methods we might need from the
#    # abstraction layer for a remote filesystem.
#    def upload(self, local_src, remote_dst):
#        pass
#    def download(self, remote_src, local_dst):
#        pass


class FS(LocalFS):

    memoizer_counters = []

    def __init__(self, path = None):
        """Initialize the Node.FS subsystem.

        The supplied path is the top of the source tree, where we
        expect to find the top-level build file.  If no path is
        supplied, the current directory is the default.

        The path argument must be a valid absolute path.
        """
        if __debug__: logInstanceCreation(self, 'Node.FS')

        self._memo = {}

        self.Root = {}
        self.SConstruct_dir = None
        self.max_drift = default_max_drift

        self.Top = None
        if path is None:
            self.pathTop = os.getcwd()
        else:
            self.pathTop = path
        self.defaultDrive = _my_normcase(os.path.splitdrive(self.pathTop)[0])

        self.Top = self.Dir(self.pathTop)
        self.Top.path = '.'
        self.Top.tpath = '.'
        self._cwd = self.Top

        DirNodeInfo.fs = self
        FileNodeInfo.fs = self
    
    def set_SConstruct_dir(self, dir):
        self.SConstruct_dir = dir

    def get_max_drift(self):
        return self.max_drift

    def set_max_drift(self, max_drift):
        self.max_drift = max_drift

    def getcwd(self):
        return self._cwd

    def chdir(self, dir, change_os_dir=0):
        """Change the current working directory for lookups.
        If change_os_dir is true, we will also change the "real" cwd
        to match.
        """
        curr=self._cwd
        try:
            if dir is not None:
                self._cwd = dir
                if change_os_dir:
                    os.chdir(dir.abspath)
        except OSError:
            self._cwd = curr
            raise

    def get_root(self, drive):
        """
        Returns the root directory for the specified drive, creating
        it if necessary.
        """
        drive = _my_normcase(drive)
        try:
            return self.Root[drive]
        except KeyError:
            root = RootDir(drive, self)
            self.Root[drive] = root
            if not drive:
                self.Root[self.defaultDrive] = root
            elif drive == self.defaultDrive:
                self.Root[''] = root
            return root

    def _lookup(self, p, directory, fsclass, create=1):
        """
        The generic entry point for Node lookup with user-supplied data.

        This translates arbitrary input into a canonical Node.FS object
        of the specified fsclass.  The general approach for strings is
        to turn it into a fully normalized absolute path and then call
        the root directory's lookup_abs() method for the heavy lifting.

        If the path name begins with '#', it is unconditionally
        interpreted relative to the top-level directory of this FS.  '#'
        is treated as a synonym for the top-level SConstruct directory,
        much like '~' is treated as a synonym for the user's home
        directory in a UNIX shell.  So both '#foo' and '#/foo' refer
        to the 'foo' subdirectory underneath the top-level SConstruct
        directory.

        If the path name is relative, then the path is looked up relative
        to the specified directory, or the current directory (self._cwd,
        typically the SConscript directory) if the specified directory
        is None.
        """
        if isinstance(p, Base):
            # It's already a Node.FS object.  Make sure it's the right
            # class and return.
            p.must_be_same(fsclass)
            return p
        # str(p) in case it's something like a proxy object
        p = str(p)

        initial_hash = (p[0:1] == '#')
        if initial_hash:
            # There was an initial '#', so we strip it and override
            # whatever directory they may have specified with the
            # top-level SConstruct directory.
            p = p[1:]
            directory = self.Top

        if directory and not isinstance(directory, Dir):
            directory = self.Dir(directory)

        if do_splitdrive:
            drive, p = os.path.splitdrive(p)
        else:
            drive = ''
        if drive and not p:
            # This causes a naked drive letter to be treated as a synonym
            # for the root directory on that drive.
            p = os.sep
        absolute = os.path.isabs(p)

        needs_normpath = needs_normpath_check.match(p)

        if initial_hash or not absolute:
            # This is a relative lookup, either to the top-level
            # SConstruct directory (because of the initial '#') or to
            # the current directory (the path name is not absolute).
            # Add the string to the appropriate directory lookup path,
            # after which the whole thing gets normalized.
            if not directory:
                directory = self._cwd
            if p:
                p = directory.labspath + '/' + p
            else:
                p = directory.labspath

        if needs_normpath:
            p = os.path.normpath(p)

        if drive or absolute:
            root = self.get_root(drive)
        else:
            if not directory:
                directory = self._cwd
            root = directory.root

        if os.sep != '/':
            p = p.replace(os.sep, '/')
        return root._lookup_abs(p, fsclass, create)

    def Entry(self, name, directory = None, create = 1):
        """Look up or create a generic Entry node with the specified name.
        If the name is a relative path (begins with ./, ../, or a file
        name), then it is looked up relative to the supplied directory
        node, or to the top level directory of the FS (supplied at
        construction time) if no directory is supplied.
        """
        return self._lookup(name, directory, Entry, create)

    def File(self, name, directory = None, create = 1):
        """Look up or create a File node with the specified name.  If
        the name is a relative path (begins with ./, ../, or a file name),
        then it is looked up relative to the supplied directory node,
        or to the top level directory of the FS (supplied at construction
        time) if no directory is supplied.

        This method will raise TypeError if a directory is found at the
        specified path.
        """
        return self._lookup(name, directory, File, create)

    def Dir(self, name, directory = None, create = True):
        """Look up or create a Dir node with the specified name.  If
        the name is a relative path (begins with ./, ../, or a file name),
        then it is looked up relative to the supplied directory node,
        or to the top level directory of the FS (supplied at construction
        time) if no directory is supplied.

        This method will raise TypeError if a normal file is found at the
        specified path.
        """
        return self._lookup(name, directory, Dir, create)

    def VariantDir(self, variant_dir, src_dir, duplicate=1):
        """Link the supplied variant directory to the source directory
        for purposes of building files."""

        if not isinstance(src_dir, SCons.Node.Node):
            src_dir = self.Dir(src_dir)
        if not isinstance(variant_dir, SCons.Node.Node):
            variant_dir = self.Dir(variant_dir)
        if src_dir.is_under(variant_dir):
            raise SCons.Errors.UserError("Source directory cannot be under variant directory.")
        if variant_dir.srcdir:
            if variant_dir.srcdir == src_dir:
                return # We already did this.
            raise SCons.Errors.UserError("'%s' already has a source directory: '%s'."%(variant_dir, variant_dir.srcdir))
        variant_dir.link(src_dir, duplicate)

    def Repository(self, *dirs):
        """Specify Repository directories to search."""
        for d in dirs:
            if not isinstance(d, SCons.Node.Node):
                d = self.Dir(d)
            self.Top.addRepository(d)

    def variant_dir_target_climb(self, orig, dir, tail):
        """Create targets in corresponding variant directories

        Climb the directory tree, and look up path names
        relative to any linked variant directories we find.

        Even though this loops and walks up the tree, we don't memoize
        the return value because this is really only used to process
        the command-line targets.
        """
        targets = []
        message = None
        fmt = "building associated VariantDir targets: %s"
        start_dir = dir
        while dir:
            for bd in dir.variant_dirs:
                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)
                targets.append(self.Entry(p))
            tail = [dir.name] + tail
            dir = dir.up()
        if targets:
            message = fmt % ' '.join(map(str, targets))
        return targets, message

    def Glob(self, pathname, ondisk=True, source=True, strings=False, cwd=None):
        """
        Globs

        This is mainly a shim layer 
        """
        if cwd is None:
            cwd = self.getcwd()
        return cwd.glob(pathname, ondisk, source, strings)

class DirNodeInfo(SCons.Node.NodeInfoBase):
    # This should get reset by the FS initialization.
    current_version_id = 1

    fs = None

    def str_to_node(self, s):
        top = self.fs.Top
        root = top.root
        if do_splitdrive:
            drive, s = os.path.splitdrive(s)
            if drive:
                root = self.fs.get_root(drive)
        if not os.path.isabs(s):
            s = top.labspath + '/' + s
        return root._lookup_abs(s, Entry)

class DirBuildInfo(SCons.Node.BuildInfoBase):
    current_version_id = 1

glob_magic_check = re.compile('[*?[]')

def has_glob_magic(s):
    return glob_magic_check.search(s) is not None

class Dir(Base):
    """A class for directories in a file system.
    """

    memoizer_counters = []

    NodeInfo = DirNodeInfo
    BuildInfo = DirBuildInfo

    def __init__(self, name, directory, fs):
        if __debug__: logInstanceCreation(self, 'Node.FS.Dir')
        Base.__init__(self, name, directory, fs)
        self._morph()

    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.root = self.dir.root

        # Don't just reset the executor, replace its action list,
        # because it might have some pre-or post-actions that need to
        # be preserved.
        self.builder = get_MkdirBuilder()
        self.get_executor().set_action_list(self.builder.action)

    def diskcheck_match(self):
        diskcheck_match(self, self.isfile,
                        "File %s found where directory expected.")

    def __clearRepositoryCache(self, duplicate=None):
        """Called when we change the repository(ies) for a directory.
        This clears any cached information that is invalidated by changing
        the repository."""

        for node in self.entries.values():
            if node != self.dir:
                if node != self and isinstance(node, Dir):
                    node.__clearRepositoryCache(duplicate)
                else:
                    node.clear()
                    try:
                        del node._srcreps
                    except AttributeError:
                        pass
                    if duplicate is not None:
                        node.duplicate=duplicate

    def __resetDuplicate(self, node):
        if node != self:
            node.duplicate = node.get_dir().duplicate

    def Entry(self, name):
        """
        Looks up or creates an entry node named 'name' relative to
        this directory.
        """
        return self.fs.Entry(name, self)

    def Dir(self, name, create=True):
        """
        Looks up or creates a directory node named 'name' relative to
        this directory.
        """
        return self.fs.Dir(name, self, create)

    def File(self, name):
        """
        Looks up or creates a file node named 'name' relative to
        this directory.
        """
        return self.fs.File(name, self)

    def _lookup_rel(self, name, klass, create=1):
        """
        Looks up a *normalized* relative path name, relative to this
        directory.

        This method is intended for use by internal lookups with
        already-normalized path data.  For general-purpose lookups,
        use the Entry(), Dir() and File() methods above.

        This method does *no* input checking and will die or give
        incorrect results if it's passed a non-normalized path name (e.g.,
        a path containing '..'), an absolute path name, a top-relative
        ('#foo') path name, or any kind of object.
        """
        name = self.entry_labspath(name)
        return self.root._lookup_abs(name, klass, create)

    def link(self, srcdir, duplicate):
        """Set this directory as the variant directory for the
        supplied source directory."""
        self.srcdir = srcdir
        self.duplicate = duplicate
        self.__clearRepositoryCache(duplicate)
        srcdir.variant_dirs.append(self)

    def getRepositories(self):
        """Returns a list of repositories for this directory.
        """
  …