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mercurial: implement import hook for handling C/Python modules...
mercurial: implement import hook for handling C/Python modules There are a handful of modules that have both pure Python and C extension implementations. Currently, setup.py copies files from mercurial/pure/*.py to mercurial/ during the install process if C extensions are not available. This way, "import mercurial.X" will work whether C extensions are available or not. This approach has a few drawbacks. First, there aren't run-time checks verifying the C extensions are loaded when they should be. This could lead to accidental use of the slower pure Python modules. Second, the C extensions aren't compatible with PyPy and running Mercurial with PyPy requires installing Mercurial - you can't run ./hg from a source checkout. This makes developing while running PyPy somewhat difficult. This patch implements a PEP-302 import hook for finding and loading the modules with both C and Python implementations. When a module with dual implementations is requested for import, its import is handled by our import hook. The importer has a mechanism that controls what types of modules we allow to load. We call this loading behavior the "module load policy." There are 3 settings: * Only load C extensions * Only load pure Python * Try to load C and fall back to Python An environment variable allows overriding this policy at run time. This is mainly useful for developers and for performing actions against the source checkout (such as installing), which require overriding the default (strict) policy about requiring C extensions. The default mode for now is to allow both. This isn't proper and is technically backwards incompatible. However, it is necessary to implement a sane patch series that doesn't break the world during future bisections. The behavior will be corrected in future patch. We choose the main mercurial/__init__.py module for this code out of necessity: in a future world, if the custom module importer isn't registered, we'll fail to find/import certain modules when running from a pure installation. Without the magical import-time side-effects, *any* importer of mercurial.* modules would be required to call a function to register our importer. I'm not a fan of import time side effects and I initially attempted to do this. However, I was foiled by our own test harness, which has numerous `python` invoked scripts that "import mercurial" and fail because the importer isn't registered. Realizing this problem is probably present in random Python scripts that have been written over the years, I decided that sacrificing purity for backwards compatibility is necessary. Plus, if you are programming Python, "import" should probably "just work." It's worth noting that now that we have a custom module loader, it would be possible to hook up demand module proxies at this level instead of replacing __import__. We leave this work for another time, if it's even desired. This patch breaks importing in environments where Mercurial modules are loaded from a zip file (such as py2exe distributions). This will be addressed in a subsequent patch.

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check-seclevel.py
165 lines | 5.7 KiB | text/x-python | PythonLexer
#!/usr/bin/env python
#
# checkseclevel - checking section title levels in each online help document
import sys, os
import optparse
# import from the live mercurial repo
sys.path.insert(0, "..")
# fall back to pure modules if required C extensions are not available
sys.path.append(os.path.join('..', 'mercurial', 'pure'))
from mercurial import demandimport; demandimport.enable()
from mercurial.commands import table
from mercurial.help import helptable
from mercurial import extensions
from mercurial import minirst
from mercurial import ui as uimod
level2mark = ['"', '=', '-', '.', '#']
reservedmarks = ['"']
mark2level = {}
for m, l in zip(level2mark, xrange(len(level2mark))):
if m not in reservedmarks:
mark2level[m] = l
initlevel_topic = 0
initlevel_cmd = 1
initlevel_ext = 1
initlevel_ext_cmd = 3
def showavailables(ui, initlevel):
ui.warn((' available marks and order of them in this help: %s\n') %
(', '.join(['%r' % (m * 4) for m in level2mark[initlevel + 1:]])))
def checkseclevel(ui, doc, name, initlevel):
ui.note(('checking "%s"\n') % name)
blocks, pruned = minirst.parse(doc, 0, ['verbose'])
errorcnt = 0
curlevel = initlevel
for block in blocks:
if block['type'] != 'section':
continue
mark = block['underline']
title = block['lines'][0]
if (mark not in mark2level) or (mark2level[mark] <= initlevel):
ui.warn(('invalid section mark %r for "%s" of %s\n') %
(mark * 4, title, name))
showavailables(ui, initlevel)
errorcnt += 1
continue
nextlevel = mark2level[mark]
if curlevel < nextlevel and curlevel + 1 != nextlevel:
ui.warn(('gap of section level at "%s" of %s\n') %
(title, name))
showavailables(ui, initlevel)
errorcnt += 1
continue
ui.note(('appropriate section level for "%s %s"\n') %
(mark * (nextlevel * 2), title))
curlevel = nextlevel
return errorcnt
def checkcmdtable(ui, cmdtable, namefmt, initlevel):
errorcnt = 0
for k, entry in cmdtable.items():
name = k.split("|")[0].lstrip("^")
if not entry[0].__doc__:
ui.note(('skip checking %s: no help document\n') %
(namefmt % name))
continue
errorcnt += checkseclevel(ui, entry[0].__doc__,
namefmt % name,
initlevel)
return errorcnt
def checkhghelps(ui):
errorcnt = 0
for names, sec, doc in helptable:
if callable(doc):
doc = doc(ui)
errorcnt += checkseclevel(ui, doc,
'%s help topic' % names[0],
initlevel_topic)
errorcnt += checkcmdtable(ui, table, '%s command', initlevel_cmd)
for name in sorted(extensions.enabled().keys() +
extensions.disabled().keys()):
mod = extensions.load(None, name, None)
if not mod.__doc__:
ui.note(('skip checking %s extension: no help document\n') % name)
continue
errorcnt += checkseclevel(ui, mod.__doc__,
'%s extension' % name,
initlevel_ext)
cmdtable = getattr(mod, 'cmdtable', None)
if cmdtable:
errorcnt += checkcmdtable(ui, cmdtable,
'%s command of ' + name + ' extension',
initlevel_ext_cmd)
return errorcnt
def checkfile(ui, filename, initlevel):
if filename == '-':
filename = 'stdin'
doc = sys.stdin.read()
else:
fp = open(filename)
try:
doc = fp.read()
finally:
fp.close()
ui.note(('checking input from %s with initlevel %d\n') %
(filename, initlevel))
return checkseclevel(ui, doc, 'input from %s' % filename, initlevel)
def main():
optparser = optparse.OptionParser("""%prog [options]
This checks all help documents of Mercurial (topics, commands,
extensions and commands of them), if no file is specified by --file
option.
""")
optparser.add_option("-v", "--verbose",
help="enable additional output",
action="store_true")
optparser.add_option("-f", "--file",
help="filename to read in (or '-' for stdin)",
action="store", default="")
optparser.add_option("-t", "--topic",
help="parse file as help topic",
action="store_const", dest="initlevel", const=0)
optparser.add_option("-c", "--command",
help="parse file as help of core command",
action="store_const", dest="initlevel", const=1)
optparser.add_option("-e", "--extension",
help="parse file as help of extension",
action="store_const", dest="initlevel", const=1)
optparser.add_option("-C", "--extension-command",
help="parse file as help of extension command",
action="store_const", dest="initlevel", const=3)
optparser.add_option("-l", "--initlevel",
help="set initial section level manually",
action="store", type="int", default=0)
(options, args) = optparser.parse_args()
ui = uimod.ui()
ui.setconfig('ui', 'verbose', options.verbose, '--verbose')
if options.file:
if checkfile(ui, options.file, options.initlevel):
sys.exit(1)
else:
if checkhghelps(ui):
sys.exit(1)
if __name__ == "__main__":
main()