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#
# 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:
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