Mercurial > hg
view mercurial/__init__.py @ 28240:1ac8ce137377
changegroup: fix treemanifests on merges
The current code for generating treemanifest revisions takes the list
of files in the changeset and finds the directories from them. This
does not work for merges, since a merge may pick file A from one side
and file B from another and neither of them would appear in the
changeset's "files" list, but the manifest would still change.
Fix this by instead walking the root manifest log for all needed
revisions, storing all needed file and subdirectory revisions, then
recursively visiting the subdirectories. This also turns out to be
faster: cloning a version of hg core converted to treemanifests went
from ~28s to ~19s (timing somewhat unfair: before this patch, timed
until crash; after this patch, timed until manifests complete).
The new algorithm is used only on treemanifest repos. Although it
works equally well on flat manifests, we leave the iteration over
files in the changeset for flat manifests for now.
author | Martin von Zweigbergk <martinvonz@google.com> |
---|---|
date | Fri, 12 Feb 2016 23:09:09 -0800 |
parents | 30a20167ae29 |
children | 17b85d739b62 |
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# __init__.py - Startup and module loading logic for Mercurial. # # Copyright 2015 Gregory Szorc <gregory.szorc@gmail.com> # # This software may be used and distributed according to the terms of the # GNU General Public License version 2 or any later version. from __future__ import absolute_import import imp import os import sys import zipimport __all__ = [] # Rules for how modules can be loaded. Values are: # # c - require C extensions # allow - allow pure Python implementation when C loading fails # py - only load pure Python modules modulepolicy = '@MODULELOADPOLICY@' # By default, require the C extensions for performance reasons. if modulepolicy == '@' 'MODULELOADPOLICY' '@': modulepolicy = 'c' # PyPy doesn't load C extensions. # # The canonical way to do this is to test platform.python_implementation(). # But we don't import platform and don't bloat for it here. if '__pypy__' in sys.builtin_module_names: modulepolicy = 'py' # Environment variable can always force settings. modulepolicy = os.environ.get('HGMODULEPOLICY', modulepolicy) # Modules that have both Python and C implementations. See also the # set of .py files under mercurial/pure/. _dualmodules = set([ 'mercurial.base85', 'mercurial.bdiff', 'mercurial.diffhelpers', 'mercurial.mpatch', 'mercurial.osutil', 'mercurial.parsers', ]) class hgimporter(object): """Object that conforms to import hook interface defined in PEP-302.""" def find_module(self, name, path=None): # We only care about modules that have both C and pure implementations. if name in _dualmodules: return self return None def load_module(self, name): mod = sys.modules.get(name, None) if mod: return mod mercurial = sys.modules['mercurial'] # The zip importer behaves sufficiently differently from the default # importer to warrant its own code path. loader = getattr(mercurial, '__loader__', None) if isinstance(loader, zipimport.zipimporter): def ziploader(*paths): """Obtain a zipimporter for a directory under the main zip.""" path = os.path.join(loader.archive, *paths) zl = sys.path_importer_cache.get(path) if not zl: zl = zipimport.zipimporter(path) return zl try: if modulepolicy == 'py': raise ImportError() zl = ziploader('mercurial') mod = zl.load_module(name) # Unlike imp, ziploader doesn't expose module metadata that # indicates the type of module. So just assume what we found # is OK (even though it could be a pure Python module). except ImportError: if modulepolicy == 'c': raise zl = ziploader('mercurial', 'pure') mod = zl.load_module(name) sys.modules[name] = mod return mod # Unlike the default importer which searches special locations and # sys.path, we only look in the directory where "mercurial" was # imported from. # imp.find_module doesn't support submodules (modules with "."). # Instead you have to pass the parent package's __path__ attribute # as the path argument. stem = name.split('.')[-1] try: if modulepolicy == 'py': raise ImportError() modinfo = imp.find_module(stem, mercurial.__path__) # The Mercurial installer used to copy files from # mercurial/pure/*.py to mercurial/*.py. Therefore, it's possible # for some installations to have .py files under mercurial/*. # Loading Python modules when we expected C versions could result # in a) poor performance b) loading a version from a previous # Mercurial version, potentially leading to incompatibility. Either # scenario is bad. So we verify that modules loaded from # mercurial/* are C extensions. If the current policy allows the # loading of .py modules, the module will be re-imported from # mercurial/pure/* below. if modinfo[2][2] != imp.C_EXTENSION: raise ImportError('.py version of %s found where C ' 'version should exist' % name) except ImportError: if modulepolicy == 'c': raise # Could not load the C extension and pure Python is allowed. So # try to load them. from . import pure modinfo = imp.find_module(stem, pure.__path__) if not modinfo: raise ImportError('could not find mercurial module %s' % name) mod = imp.load_module(name, *modinfo) sys.modules[name] = mod return mod # We automagically register our custom importer as a side-effect of loading. # This is necessary to ensure that any entry points are able to import # mercurial.* modules without having to perform this registration themselves. if not any(isinstance(x, hgimporter) for x in sys.meta_path): # meta_path is used before any implicit finders and before sys.path. sys.meta_path.insert(0, hgimporter())