Mercurial > hg
view mercurial/pycompat.py @ 30350:358cda0af6ee
util: create new abstraction for compression engines
Currently, util.py has "compressors" and "decompressors" dicts
mapping compression algorithms to callables returning objects that
perform well-defined operations. In addition, revlog.py has code
for calling into a compressor or decompressor explicitly. And, there
is code in the wire protocol for performing zlib compression.
The 3rd party lz4revlog extension has demonstrated the utility of
supporting alternative compression formats for revlog storage. But
it stops short of supporting lz4 for bundles and the wire protocol.
There are also plans to support zstd as a general compression
replacement.
So, there appears to be a market for a unified API for registering
compression engines. This commit starts the process of establishing
one.
This commit establishes a base class/interface for defining
compression engines and how they will be used. A collection class
to hold references to registered compression engines has also been
introduced.
The built-in zlib, bz2, truncated bz2, and no-op compression engines
are registered with a singleton instance of the collection class.
The compression engine API will change once consumers are ported
to the new API and some common patterns can be simplified at the
engine API level. So don't get too attached to the API...
author | Gregory Szorc <gregory.szorc@gmail.com> |
---|---|
date | Mon, 07 Nov 2016 18:31:39 -0800 |
parents | 19d8e19fde5b |
children | 277f4fe6d01a |
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# pycompat.py - portability shim for python 3 # # This software may be used and distributed according to the terms of the # GNU General Public License version 2 or any later version. """Mercurial portability shim for python 3. This contains aliases to hide python version-specific details from the core. """ from __future__ import absolute_import import os import sys ispy3 = (sys.version_info[0] >= 3) if not ispy3: import cPickle as pickle import cStringIO as io import httplib import Queue as _queue import SocketServer as socketserver import urlparse urlunquote = urlparse.unquote import xmlrpclib else: import http.client as httplib import io import pickle import queue as _queue import socketserver import urllib.parse as urlparse urlunquote = urlparse.unquote_to_bytes import xmlrpc.client as xmlrpclib if ispy3: import builtins import functools fsencode = os.fsencode fsdecode = os.fsdecode # A bytes version of os.name. osname = os.name.encode('ascii') ospathsep = os.pathsep.encode('ascii') ossep = os.sep.encode('ascii') # Since Python 3 converts argv to wchar_t type by Py_DecodeLocale() on Unix, # we can use os.fsencode() to get back bytes argv. # # https://hg.python.org/cpython/file/v3.5.1/Programs/python.c#l55 # # TODO: On Windows, the native argv is wchar_t, so we'll need a different # workaround to simulate the Python 2 (i.e. ANSI Win32 API) behavior. sysargv = list(map(os.fsencode, sys.argv)) def sysstr(s): """Return a keyword str to be passed to Python functions such as getattr() and str.encode() This never raises UnicodeDecodeError. Non-ascii characters are considered invalid and mapped to arbitrary but unique code points such that 'sysstr(a) != sysstr(b)' for all 'a != b'. """ if isinstance(s, builtins.str): return s return s.decode(u'latin-1') def _wrapattrfunc(f): @functools.wraps(f) def w(object, name, *args): return f(object, sysstr(name), *args) return w # these wrappers are automagically imported by hgloader delattr = _wrapattrfunc(builtins.delattr) getattr = _wrapattrfunc(builtins.getattr) hasattr = _wrapattrfunc(builtins.hasattr) setattr = _wrapattrfunc(builtins.setattr) xrange = builtins.range else: def sysstr(s): return s # Partial backport from os.py in Python 3, which only accepts bytes. # In Python 2, our paths should only ever be bytes, a unicode path # indicates a bug. def fsencode(filename): if isinstance(filename, str): return filename else: raise TypeError( "expect str, not %s" % type(filename).__name__) # In Python 2, fsdecode() has a very chance to receive bytes. So it's # better not to touch Python 2 part as it's already working fine. def fsdecode(filename): return filename osname = os.name ospathsep = os.pathsep ossep = os.sep sysargv = sys.argv stringio = io.StringIO empty = _queue.Empty queue = _queue.Queue class _pycompatstub(object): def __init__(self): self._aliases = {} def _registeraliases(self, origin, items): """Add items that will be populated at the first access""" items = map(sysstr, items) self._aliases.update( (item.replace(sysstr('_'), sysstr('')).lower(), (origin, item)) for item in items) def __getattr__(self, name): try: origin, item = self._aliases[name] except KeyError: raise AttributeError(name) self.__dict__[name] = obj = getattr(origin, item) return obj httpserver = _pycompatstub() urlreq = _pycompatstub() urlerr = _pycompatstub() if not ispy3: import BaseHTTPServer import CGIHTTPServer import SimpleHTTPServer import urllib2 import urllib urlreq._registeraliases(urllib, ( "addclosehook", "addinfourl", "ftpwrapper", "pathname2url", "quote", "splitattr", "splitpasswd", "splitport", "splituser", "unquote", "url2pathname", "urlencode", )) urlreq._registeraliases(urllib2, ( "AbstractHTTPHandler", "BaseHandler", "build_opener", "FileHandler", "FTPHandler", "HTTPBasicAuthHandler", "HTTPDigestAuthHandler", "HTTPHandler", "HTTPPasswordMgrWithDefaultRealm", "HTTPSHandler", "install_opener", "ProxyHandler", "Request", "urlopen", )) urlerr._registeraliases(urllib2, ( "HTTPError", "URLError", )) httpserver._registeraliases(BaseHTTPServer, ( "HTTPServer", "BaseHTTPRequestHandler", )) httpserver._registeraliases(SimpleHTTPServer, ( "SimpleHTTPRequestHandler", )) httpserver._registeraliases(CGIHTTPServer, ( "CGIHTTPRequestHandler", )) else: import urllib.request urlreq._registeraliases(urllib.request, ( "AbstractHTTPHandler", "addclosehook", "addinfourl", "BaseHandler", "build_opener", "FileHandler", "FTPHandler", "ftpwrapper", "HTTPHandler", "HTTPSHandler", "install_opener", "pathname2url", "HTTPBasicAuthHandler", "HTTPDigestAuthHandler", "HTTPPasswordMgrWithDefaultRealm", "ProxyHandler", "quote", "Request", "splitattr", "splitpasswd", "splitport", "splituser", "unquote", "url2pathname", "urlopen", )) import urllib.error urlerr._registeraliases(urllib.error, ( "HTTPError", "URLError", )) import http.server httpserver._registeraliases(http.server, ( "HTTPServer", "BaseHTTPRequestHandler", "SimpleHTTPRequestHandler", "CGIHTTPRequestHandler", ))