The Tor Browser: config/expandlibs.py@97036ab72558 (annotated)

config/expandlibs.py@97036ab72558 (annotated)

config/expandlibs.py

Tue, 06 Jan 2015 21:39:09 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Tue, 06 Jan 2015 21:39:09 +0100
branch: TOR_BUG_9701
changeset 8: 97036ab72558
permissions: -rw-r--r--

Conditionally force memory storage according to privacy.thirdparty.isolate;
This solves Tor bug #9701, complying with disk avoidance documented in
https://www.torproject.org/projects/torbrowser/design/#disk-avoidance.

 # This Source Code Form is subject to the terms of the Mozilla Public
 # License, v. 2.0. If a copy of the MPL was not distributed with this
 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
 '''Expandlibs is a system that allows to replace some libraries with a
 descriptor file containing some linking information about them.
 The descriptor file format is as follows:
 ---8<-----
 OBJS = a.o b.o ...
 LIBS = libfoo.a libbar.a ...
 --->8-----
 (In the example above, OBJ_SUFFIX is o and LIB_SUFFIX is a).
 Expandlibs also canonicalizes how to pass libraries to the linker, such
 that only the ${LIB_PREFIX}${ROOT}.${LIB_SUFFIX} form needs to be used:
 given a list of files, expandlibs will replace items with the form
 ${LIB_PREFIX}${ROOT}.${LIB_SUFFIX} following these rules:
 - If a ${DLL_PREFIX}${ROOT}.${DLL_SUFFIX} or
   ${DLL_PREFIX}${ROOT}.${IMPORT_LIB_SUFFIX} file exists, use that instead
 - If the ${LIB_PREFIX}${ROOT}.${LIB_SUFFIX} file exists, use it
 - If a ${LIB_PREFIX}${ROOT}.${LIB_SUFFIX}.${LIB_DESC_SUFFIX} file exists,
   replace ${LIB_PREFIX}${ROOT}.${LIB_SUFFIX} with the OBJS and LIBS the
   descriptor contains. And for each of these LIBS, also apply the same
   rules.
 '''
 from __future__ import with_statement
 import sys, os, errno
 import expandlibs_config as conf
 def ensureParentDir(file):
     '''Ensures the directory parent to the given file exists'''
     dir = os.path.dirname(file)
     if dir and not os.path.exists(dir):
         try:
             os.makedirs(dir)
         except OSError, error:
             if error.errno != errno.EEXIST:
                 raise
 def relativize(path):
     '''Returns a path relative to the current working directory, if it is
     shorter than the given path'''
     def splitpath(path):
         dir, file = os.path.split(path)
         if os.path.splitdrive(dir)[1] == os.sep:
             return [file]
         return splitpath(dir) + [file]
     if not os.path.exists(path):
         return path
     curdir = splitpath(os.path.abspath(os.curdir))
     abspath = splitpath(os.path.abspath(path))
     while curdir and abspath and curdir[0] == abspath[0]:
         del curdir[0]
         del abspath[0]
     if not curdir and not abspath:
         return '.'
     relpath = os.path.join(*[os.pardir for i in curdir] + abspath)
     if len(path) > len(relpath):
         return relpath
     return path
 def isObject(path):
     '''Returns whether the given path points to an object file, that is,
     ends with OBJ_SUFFIX or .i_o'''
     return os.path.splitext(path)[1] in [conf.OBJ_SUFFIX, '.i_o']
 def isDynamicLib(path):
     '''Returns whether the given path points to a dynamic library, that is,
     ends with DLL_SUFFIX.'''
     # On mac, the xul library is named XUL, instead of libxul.dylib. Assume any
     # file by that name is a dynamic library.
     return os.path.splitext(path)[1] == conf.DLL_SUFFIX or os.path.basename(path) == 'XUL'
 class LibDescriptor(dict):
     KEYS = ['OBJS', 'LIBS']
     def __init__(self, content=None):
         '''Creates an instance of a lib descriptor, initialized with contents
         from a list of strings when given. This is intended for use with
         file.readlines()'''
         if isinstance(content, list) and all([isinstance(item, str) for item in content]):
             pass
         elif content is not None:
             raise TypeError("LibDescriptor() arg 1 must be None or a list of strings")
         super(LibDescriptor, self).__init__()
         for key in self.KEYS:
             self[key] = []
         if not content:
             return
         for key, value in [(s.strip() for s in item.split('=', 2)) for item in content if item.find('=') >= 0]:
             if key in self.KEYS:
                 self[key] = value.split()
     def __str__(self):
         '''Serializes the lib descriptor'''
         return '\n'.join('%s = %s' % (k, ' '.join(self[k])) for k in self.KEYS if len(self[k]))
 class ExpandArgs(list):
     def __init__(self, args):
         '''Creates a clone of the |args| list and performs file expansion on
         each item it contains'''
         super(ExpandArgs, self).__init__()
         for arg in args:
             self += self._expand(arg)
     def _expand(self, arg):
         '''Internal function doing the actual work'''
         (root, ext) = os.path.splitext(arg)
         if ext != conf.LIB_SUFFIX or not os.path.basename(root).startswith(conf.LIB_PREFIX):
             return [relativize(arg)]
         if len(conf.IMPORT_LIB_SUFFIX):
             dll = root + conf.IMPORT_LIB_SUFFIX
         else:
             dll = root.replace(conf.LIB_PREFIX, conf.DLL_PREFIX, 1) + conf.DLL_SUFFIX
         if os.path.exists(dll):
             return [relativize(dll)]
         if os.path.exists(arg):
             return [relativize(arg)]
         return self._expand_desc(arg)
     def _expand_desc(self, arg):
         '''Internal function taking care of lib descriptor expansion only'''
         if os.path.exists(arg + conf.LIBS_DESC_SUFFIX):
             with open(arg + conf.LIBS_DESC_SUFFIX, 'r') as f:
                 desc = LibDescriptor(f.readlines())
             objs = [relativize(o) for o in desc['OBJS']]
             for lib in desc['LIBS']:
                 objs += self._expand(lib)
             return objs
         return [arg]
 class ExpandLibsDeps(ExpandArgs):
     '''Same as ExpandArgs, but also adds the library descriptor to the list'''
     def _expand_desc(self, arg):
         objs = super(ExpandLibsDeps, self)._expand_desc(arg)
         if os.path.exists(arg + conf.LIBS_DESC_SUFFIX):
             objs += [relativize(arg + conf.LIBS_DESC_SUFFIX)]
         return objs
 if __name__ == '__main__':
     print " ".join(ExpandArgs(sys.argv[1:]))

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config/expandlibs.py@97036ab72558 (annotated)

config/expandlibs.py