Added an unmodified copy of SCons to third_party.

scons-2.0.1/engine/SCons/CacheDir.py

+#
+# 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/CacheDir.py 5134 2010/08/16 23:02:40 bdeegan"
+
+__doc__ = """
+CacheDir support
+"""
+
+import os.path
+import stat
+import sys
+
+import SCons.Action
+
+cache_enabled = True
+cache_debug = False
+cache_force = False
+cache_show = False
+
+def CacheRetrieveFunc(target, source, env):
+    t = target[0]
+    fs = t.fs
+    cd = env.get_CacheDir()
+    cachedir, cachefile = cd.cachepath(t)
+    if not fs.exists(cachefile):
+        cd.CacheDebug('CacheRetrieve(%s):  %s not in cache\n', t, cachefile)
+        return 1
+    cd.CacheDebug('CacheRetrieve(%s):  retrieving from %s\n', t, cachefile)
+    if SCons.Action.execute_actions:
+        if fs.islink(cachefile):
+            fs.symlink(fs.readlink(cachefile), t.path)
+        else:
+            env.copy_from_cache(cachefile, t.path)
+        st = fs.stat(cachefile)
+        fs.chmod(t.path, stat.S_IMODE(st[stat.ST_MODE]) | stat.S_IWRITE)
+    return 0
+
+def CacheRetrieveString(target, source, env):
+    t = target[0]
+    fs = t.fs
+    cd = env.get_CacheDir()
+    cachedir, cachefile = cd.cachepath(t)
+    if t.fs.exists(cachefile):
+        return "Retrieved `%s' from cache" % t.path
+    return None
+
+CacheRetrieve = SCons.Action.Action(CacheRetrieveFunc, CacheRetrieveString)
+
+CacheRetrieveSilent = SCons.Action.Action(CacheRetrieveFunc, None)
+
+def CachePushFunc(target, source, env):
+    t = target[0]
+    if t.nocache:
+        return
+    fs = t.fs
+    cd = env.get_CacheDir()
+    cachedir, cachefile = cd.cachepath(t)
+    if fs.exists(cachefile):
+        # Don't bother copying it if it's already there.  Note that
+        # usually this "shouldn't happen" because if the file already
+        # existed in cache, we'd have retrieved the file from there,
+        # not built it.  This can happen, though, in a race, if some
+        # other person running the same build pushes their copy to
+        # the cache after we decide we need to build it but before our
+        # build completes.
+        cd.CacheDebug('CachePush(%s):  %s already exists in cache\n', t, cachefile)
+        return
+
+    cd.CacheDebug('CachePush(%s):  pushing to %s\n', t, cachefile)
+
+    tempfile = cachefile+'.tmp'+str(os.getpid())
+    errfmt = "Unable to copy %s to cache. Cache file is %s"
+
+    if not fs.isdir(cachedir):
+        try:
+            fs.makedirs(cachedir)
+        except EnvironmentError:
+            # We may have received an exception because another process
+            # has beaten us creating the directory.
+            if not fs.isdir(cachedir):
+                msg = errfmt % (str(target), cachefile)
+                raise SCons.Errors.EnvironmentError(msg)
+
+    try:
+        if fs.islink(t.path):
+            fs.symlink(fs.readlink(t.path), tempfile)
+        else:
+            fs.copy2(t.path, tempfile)
+        fs.rename(tempfile, cachefile)
+        st = fs.stat(t.path)
+        fs.chmod(cachefile, stat.S_IMODE(st[stat.ST_MODE]) | stat.S_IWRITE)
+    except EnvironmentError:
+        # It's possible someone else tried writing the file at the
+        # same time we did, or else that there was some problem like
+        # the CacheDir being on a separate file system that's full.
+        # In any case, inability to push a file to cache doesn't affect
+        # the correctness of the build, so just print a warning.
+        msg = errfmt % (str(target), cachefile)
+        SCons.Warnings.warn(SCons.Warnings.CacheWriteErrorWarning, msg)
+
+CachePush = SCons.Action.Action(CachePushFunc, None)
+
+class CacheDir(object):
+
+    def __init__(self, path):
+        try:
+            import hashlib
+        except ImportError:
+            msg = "No hashlib or MD5 module available, CacheDir() not supported"
+            SCons.Warnings.warn(SCons.Warnings.NoMD5ModuleWarning, msg)
+            self.path = None
+        else:
+            self.path = path
+        self.current_cache_debug = None
+        self.debugFP = None
+
+    def CacheDebug(self, fmt, target, cachefile):
+        if cache_debug != self.current_cache_debug:
+            if cache_debug == '-':
+                self.debugFP = sys.stdout
+            elif cache_debug:
+                self.debugFP = open(cache_debug, 'w')
+            else:
+                self.debugFP = None
+            self.current_cache_debug = cache_debug
+        if self.debugFP:
+            self.debugFP.write(fmt % (target, os.path.split(cachefile)[1]))
+
+    def is_enabled(self):
+        return (cache_enabled and not self.path is None)
+
+    def cachepath(self, node):
+        """
+        """
+        if not self.is_enabled():
+            return None, None
+
+        sig = node.get_cachedir_bsig()
+        subdir = sig[0].upper()
+        dir = os.path.join(self.path, subdir)
+        return dir, os.path.join(dir, sig)
+
+    def retrieve(self, node):
+        """
+        This method is called from multiple threads in a parallel build,
+        so only do thread safe stuff here. Do thread unsafe stuff in
+        built().
+
+        Note that there's a special trick here with the execute flag
+        (one that's not normally done for other actions).  Basically
+        if the user requested a no_exec (-n) build, then
+        SCons.Action.execute_actions is set to 0 and when any action
+        is called, it does its showing but then just returns zero
+        instead of actually calling the action execution operation.
+        The problem for caching is that if the file does NOT exist in
+        cache then the CacheRetrieveString won't return anything to
+        show for the task, but the Action.__call__ won't call
+        CacheRetrieveFunc; instead it just returns zero, which makes
+        the code below think that the file *was* successfully
+        retrieved from the cache, therefore it doesn't do any
+        subsequent building.  However, the CacheRetrieveString didn't
+        print anything because it didn't actually exist in the cache,
+        and no more build actions will be performed, so the user just
+        sees nothing.  The fix is to tell Action.__call__ to always
+        execute the CacheRetrieveFunc and then have the latter
+        explicitly check SCons.Action.execute_actions itself.
+        """
+        if not self.is_enabled():
+            return False
+
+        env = node.get_build_env()
+        if cache_show:
+            if CacheRetrieveSilent(node, [], env, execute=1) == 0:
+                node.build(presub=0, execute=0)
+                return True
+        else:
+            if CacheRetrieve(node, [], env, execute=1) == 0:
+                return True
+
+        return False
+
+    def push(self, node):
+        if not self.is_enabled():
+            return
+        return CachePush(node, [], node.get_build_env())
+
+    def push_if_forced(self, node):
+        if cache_force:
+            return self.push(node)
+
+# Local Variables:
+# tab-width:4
+# indent-tabs-mode:nil
+# End:
+# vim: set expandtab tabstop=4 shiftwidth=4: