281 lines
11 KiB
Python
281 lines
11 KiB
Python
#
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# Copyright (c) 2001 - 2016 The SCons Foundation
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#
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# Permission is hereby granted, free of charge, to any person obtaining
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# a copy of this software and associated documentation files (the
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# "Software"), to deal in the Software without restriction, including
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# without limitation the rights to use, copy, modify, merge, publish,
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# distribute, sublicense, and/or sell copies of the Software, and to
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# permit persons to whom the Software is furnished to do so, subject to
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# the following conditions:
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#
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# The above copyright notice and this permission notice shall be included
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# in all copies or substantial portions of the Software.
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#
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# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY
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# KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
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# WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
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# LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
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# OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
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# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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#
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__revision__ = "src/engine/SCons/CacheDir.py rel_2.5.0:3543:937e55cd78f7 2016/04/09 11:29:54 bdbaddog"
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__doc__ = """
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CacheDir support
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"""
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import json
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import os
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import stat
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import sys
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import SCons.Action
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import SCons.Warnings
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cache_enabled = True
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cache_debug = False
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cache_force = False
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cache_show = False
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cache_readonly = False
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def CacheRetrieveFunc(target, source, env):
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t = target[0]
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fs = t.fs
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cd = env.get_CacheDir()
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cachedir, cachefile = cd.cachepath(t)
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if not fs.exists(cachefile):
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cd.CacheDebug('CacheRetrieve(%s): %s not in cache\n', t, cachefile)
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return 1
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cd.CacheDebug('CacheRetrieve(%s): retrieving from %s\n', t, cachefile)
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if SCons.Action.execute_actions:
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if fs.islink(cachefile):
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fs.symlink(fs.readlink(cachefile), t.get_internal_path())
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else:
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env.copy_from_cache(cachefile, t.get_internal_path())
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st = fs.stat(cachefile)
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fs.chmod(t.get_internal_path(), stat.S_IMODE(st[stat.ST_MODE]) | stat.S_IWRITE)
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return 0
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def CacheRetrieveString(target, source, env):
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t = target[0]
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fs = t.fs
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cd = env.get_CacheDir()
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cachedir, cachefile = cd.cachepath(t)
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if t.fs.exists(cachefile):
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return "Retrieved `%s' from cache" % t.get_internal_path()
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return None
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CacheRetrieve = SCons.Action.Action(CacheRetrieveFunc, CacheRetrieveString)
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CacheRetrieveSilent = SCons.Action.Action(CacheRetrieveFunc, None)
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def CachePushFunc(target, source, env):
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if cache_readonly:
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return
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t = target[0]
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if t.nocache:
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return
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fs = t.fs
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cd = env.get_CacheDir()
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cachedir, cachefile = cd.cachepath(t)
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if fs.exists(cachefile):
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# Don't bother copying it if it's already there. Note that
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# usually this "shouldn't happen" because if the file already
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# existed in cache, we'd have retrieved the file from there,
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# not built it. This can happen, though, in a race, if some
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# other person running the same build pushes their copy to
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# the cache after we decide we need to build it but before our
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# build completes.
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cd.CacheDebug('CachePush(%s): %s already exists in cache\n', t, cachefile)
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return
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cd.CacheDebug('CachePush(%s): pushing to %s\n', t, cachefile)
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tempfile = cachefile+'.tmp'+str(os.getpid())
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errfmt = "Unable to copy %s to cache. Cache file is %s"
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if not fs.isdir(cachedir):
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try:
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fs.makedirs(cachedir)
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except EnvironmentError:
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# We may have received an exception because another process
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# has beaten us creating the directory.
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if not fs.isdir(cachedir):
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msg = errfmt % (str(target), cachefile)
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raise SCons.Errors.EnvironmentError(msg)
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try:
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if fs.islink(t.get_internal_path()):
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fs.symlink(fs.readlink(t.get_internal_path()), tempfile)
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else:
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fs.copy2(t.get_internal_path(), tempfile)
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fs.rename(tempfile, cachefile)
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st = fs.stat(t.get_internal_path())
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fs.chmod(cachefile, stat.S_IMODE(st[stat.ST_MODE]) | stat.S_IWRITE)
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except EnvironmentError:
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# It's possible someone else tried writing the file at the
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# same time we did, or else that there was some problem like
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# the CacheDir being on a separate file system that's full.
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# In any case, inability to push a file to cache doesn't affect
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# the correctness of the build, so just print a warning.
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msg = errfmt % (str(target), cachefile)
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SCons.Warnings.warn(SCons.Warnings.CacheWriteErrorWarning, msg)
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CachePush = SCons.Action.Action(CachePushFunc, None)
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# Nasty hack to cut down to one warning for each cachedir path that needs
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# upgrading.
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warned = dict()
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class CacheDir(object):
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def __init__(self, path):
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try:
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import hashlib
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except ImportError:
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msg = "No hashlib or MD5 module available, CacheDir() not supported"
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SCons.Warnings.warn(SCons.Warnings.NoMD5ModuleWarning, msg)
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path = None
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self.path = path
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self.current_cache_debug = None
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self.debugFP = None
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self.config = dict()
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if path is None:
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return
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# See if there's a config file in the cache directory. If there is,
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# use it. If there isn't, and the directory exists and isn't empty,
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# produce a warning. If the directory doesn't exist or is empty,
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# write a config file.
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config_file = os.path.join(path, 'config')
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if not os.path.exists(config_file):
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# A note: There is a race hazard here, if two processes start and
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# attempt to create the cache directory at the same time. However,
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# python doesn't really give you the option to do exclusive file
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# creation (it doesn't even give you the option to error on opening
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# an existing file for writing...). The ordering of events here
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# as an attempt to alleviate this, on the basis that it's a pretty
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# unlikely occurence (it'd require two builds with a brand new cache
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# directory)
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if os.path.isdir(path) and len(os.listdir(path)) != 0:
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self.config['prefix_len'] = 1
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# When building the project I was testing this on, the warning
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# was output over 20 times. That seems excessive
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global warned
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if self.path not in warned:
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msg = "Please upgrade your cache by running " +\
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" scons-configure-cache.py " + self.path
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SCons.Warnings.warn(SCons.Warnings.CacheVersionWarning, msg)
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warned[self.path] = True
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else:
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if not os.path.isdir(path):
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try:
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os.makedirs(path)
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except OSError:
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# If someone else is trying to create the directory at
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# the same time as me, bad things will happen
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msg = "Failed to create cache directory " + path
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raise SCons.Errors.EnvironmentError(msg)
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self.config['prefix_len'] = 2
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if not os.path.exists(config_file):
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try:
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with open(config_file, 'w') as config:
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json.dump(self.config, config)
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except:
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msg = "Failed to write cache configuration for " + path
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raise SCons.Errors.EnvironmentError(msg)
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else:
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try:
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with open(config_file) as config:
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self.config = json.load(config)
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except ValueError:
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msg = "Failed to read cache configuration for " + path
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raise SCons.Errors.EnvironmentError(msg)
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def CacheDebug(self, fmt, target, cachefile):
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if cache_debug != self.current_cache_debug:
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if cache_debug == '-':
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self.debugFP = sys.stdout
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elif cache_debug:
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self.debugFP = open(cache_debug, 'w')
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else:
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self.debugFP = None
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self.current_cache_debug = cache_debug
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if self.debugFP:
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self.debugFP.write(fmt % (target, os.path.split(cachefile)[1]))
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def is_enabled(self):
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return cache_enabled and not self.path is None
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def is_readonly(self):
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return cache_readonly
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def cachepath(self, node):
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"""
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"""
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if not self.is_enabled():
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return None, None
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sig = node.get_cachedir_bsig()
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subdir = sig[:self.config['prefix_len']].upper()
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dir = os.path.join(self.path, subdir)
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return dir, os.path.join(dir, sig)
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def retrieve(self, node):
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"""
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This method is called from multiple threads in a parallel build,
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so only do thread safe stuff here. Do thread unsafe stuff in
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built().
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Note that there's a special trick here with the execute flag
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(one that's not normally done for other actions). Basically
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if the user requested a no_exec (-n) build, then
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SCons.Action.execute_actions is set to 0 and when any action
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is called, it does its showing but then just returns zero
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instead of actually calling the action execution operation.
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The problem for caching is that if the file does NOT exist in
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cache then the CacheRetrieveString won't return anything to
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show for the task, but the Action.__call__ won't call
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CacheRetrieveFunc; instead it just returns zero, which makes
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the code below think that the file *was* successfully
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retrieved from the cache, therefore it doesn't do any
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subsequent building. However, the CacheRetrieveString didn't
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print anything because it didn't actually exist in the cache,
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and no more build actions will be performed, so the user just
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sees nothing. The fix is to tell Action.__call__ to always
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execute the CacheRetrieveFunc and then have the latter
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explicitly check SCons.Action.execute_actions itself.
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"""
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if not self.is_enabled():
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return False
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env = node.get_build_env()
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if cache_show:
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if CacheRetrieveSilent(node, [], env, execute=1) == 0:
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node.build(presub=0, execute=0)
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return True
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else:
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if CacheRetrieve(node, [], env, execute=1) == 0:
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return True
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return False
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def push(self, node):
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if self.is_readonly() or not self.is_enabled():
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return
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return CachePush(node, [], node.get_build_env())
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def push_if_forced(self, node):
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if cache_force:
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return self.push(node)
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# Local Variables:
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# tab-width:4
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# indent-tabs-mode:nil
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# End:
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# vim: set expandtab tabstop=4 shiftwidth=4:
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