opener: introduce an abstact superclass of it

Currently, this class doesn't do anything useful.

mercurial/scmutil.py

@@ -1,424 +1,431 b''
 # scmutil.py - Mercurial core utility functions
 #
 #  Copyright Matt Mackall <[e-mail]>
 #
 # This software may be used and distributed according to the terms of the
 # GNU General Public License version 2 or any later version.
 
 from i18n import _
 import util, error, osutil
 import os, errno, stat, sys
 
 def checkfilename(f):
     '''Check that the filename f is an acceptable filename for a tracked file'''
     if '\r' in f or '\n' in f:
         raise util.Abort(_("'\\n' and '\\r' disallowed in filenames: %r") % f)
 
 def checkportable(ui, f):
     '''Check if filename f is portable and warn or abort depending on config'''
     checkfilename(f)
     if showportabilityalert(ui):
         msg = util.checkwinfilename(f)
         if msg:
             portabilityalert(ui, "%s: %r" % (msg, f))
 
 def checkcasecollision(ui, f, files):
     if f.lower() in files and files[f.lower()] != f:
         portabilityalert(ui, _('possible case-folding collision for %s') % f)
     files[f.lower()] = f
 
 def checkportabilityalert(ui):
     '''check if the user's config requests nothing, a warning, or abort for
     non-portable filenames'''
     val = ui.config('ui', 'portablefilenames', 'warn')
     lval = val.lower()
     bval = util.parsebool(val)
     abort = os.name == 'nt' or lval == 'abort'
     warn = bval or lval == 'warn'
     if bval is None and not (warn or abort or lval == 'ignore'):
         raise error.ConfigError(
             _("ui.portablefilenames value is invalid ('%s')") % val)
     return abort, warn
 
 def showportabilityalert(ui):
     '''check if the user wants any notification of portability problems'''
     abort, warn = checkportabilityalert(ui)
     return abort or warn
 
 def portabilityalert(ui, msg):
     if not msg:
         return
     abort, warn = checkportabilityalert(ui)
     if abort:
         raise util.Abort("%s" % msg)
     elif warn:
         ui.warn(_("warning: %s\n") % msg)
 
 class path_auditor(object):
     '''ensure that a filesystem path contains no banned components.
     the following properties of a path are checked:
 
     - ends with a directory separator
     - under top-level .hg
     - starts at the root of a windows drive
     - contains ".."
     - traverses a symlink (e.g. a/symlink_here/b)
     - inside a nested repository (a callback can be used to approve
       some nested repositories, e.g., subrepositories)
     '''
 
     def __init__(self, root, callback=None):
         self.audited = set()
         self.auditeddir = set()
         self.root = root
         self.callback = callback
 
     def __call__(self, path):
         '''Check the relative path.
         path may contain a pattern (e.g. foodir/**.txt)'''
 
         if path in self.audited:
             return
         # AIX ignores "/" at end of path, others raise EISDIR.
         if util.endswithsep(path):
             raise util.Abort(_("path ends in directory separator: %s") % path)
         normpath = os.path.normcase(path)
         parts = util.splitpath(normpath)
         if (os.path.splitdrive(path)[0]
             or parts[0].lower() in ('.hg', '.hg.', '')
             or os.pardir in parts):
             raise util.Abort(_("path contains illegal component: %s") % path)
         if '.hg' in path.lower():
             lparts = [p.lower() for p in parts]
             for p in '.hg', '.hg.':
                 if p in lparts[1:]:
                     pos = lparts.index(p)
                     base = os.path.join(*parts[:pos])
                     raise util.Abort(_('path %r is inside nested repo %r')
                                      % (path, base))
 
         parts.pop()
         prefixes = []
         while parts:
             prefix = os.sep.join(parts)
             if prefix in self.auditeddir:
                 break
             curpath = os.path.join(self.root, prefix)
             try:
                 st = os.lstat(curpath)
             except OSError, err:
                 # EINVAL can be raised as invalid path syntax under win32.
                 # They must be ignored for patterns can be checked too.
                 if err.errno not in (errno.ENOENT, errno.ENOTDIR, errno.EINVAL):
                     raise
             else:
                 if stat.S_ISLNK(st.st_mode):
                     raise util.Abort(
                         _('path %r traverses symbolic link %r')
                         % (path, prefix))
                 elif (stat.S_ISDIR(st.st_mode) and
                       os.path.isdir(os.path.join(curpath, '.hg'))):
                     if not self.callback or not self.callback(curpath):
                         raise util.Abort(_('path %r is inside nested repo %r') %
                                          (path, prefix))
             prefixes.append(prefix)
             parts.pop()
 
         self.audited.add(path)
         # only add prefixes to the cache after checking everything: we don't
         # want to add "foo/bar/baz" before checking if there's a "foo/.hg"
         self.auditeddir.update(prefixes)
 
-class opener(object):
+class abstractopener(object):
+    """Abstract base class; cannot be instantiated"""
+
+    def __init__(self, *args, **kwargs):
+        '''Prevent instantiation; don't call this from subclasses.'''
+        raise NotImplementedError('attempted instantiating ' + str(type(self)))
+
+class opener(abstractopener):
     '''Open files relative to a base directory
 
     This class is used to hide the details of COW semantics and
     remote file access from higher level code.
     '''
     def __init__(self, base, audit=True):
         self.base = base
         if audit:
             self.auditor = path_auditor(base)
         else:
             self.auditor = util.always
         self.createmode = None
         self._trustnlink = None
 
     @util.propertycache
     def _can_symlink(self):
         return util.checklink(self.base)
 
     def _fixfilemode(self, name):
         if self.createmode is None:
             return
         os.chmod(name, self.createmode & 0666)
 
     def __call__(self, path, mode="r", text=False, atomictemp=False):
         r = util.checkosfilename(path)
         if r:
             raise util.Abort("%s: %r" % (r, path))
         self.auditor(path)
         f = os.path.join(self.base, path)
 
         if not text and "b" not in mode:
             mode += "b" # for that other OS
 
         nlink = -1
         dirname, basename = os.path.split(f)
         # If basename is empty, then the path is malformed because it points
         # to a directory. Let the posixfile() call below raise IOError.
         if basename and mode not in ('r', 'rb'):
             if atomictemp:
                 if not os.path.isdir(dirname):
                     util.makedirs(dirname, self.createmode)
                 return util.atomictempfile(f, mode, self.createmode)
             try:
                 if 'w' in mode:
                     util.unlink(f)
                     nlink = 0
                 else:
                     # nlinks() may behave differently for files on Windows
                     # shares if the file is open.
                     fd = util.posixfile(f)
                     nlink = util.nlinks(f)
                     if nlink < 1:
                         nlink = 2 # force mktempcopy (issue1922)
                     fd.close()
             except (OSError, IOError), e:
                 if e.errno != errno.ENOENT:
                     raise
                 nlink = 0
                 if not os.path.isdir(dirname):
                     util.makedirs(dirname, self.createmode)
             if nlink > 0:
                 if self._trustnlink is None:
                     self._trustnlink = nlink > 1 or util.checknlink(f)
                 if nlink > 1 or not self._trustnlink:
                     util.rename(util.mktempcopy(f), f)
         fp = util.posixfile(f, mode)
         if nlink == 0:
             self._fixfilemode(f)
         return fp
 
     def symlink(self, src, dst):
         self.auditor(dst)
         linkname = os.path.join(self.base, dst)
         try:
             os.unlink(linkname)
         except OSError:
             pass
 
         dirname = os.path.dirname(linkname)
         if not os.path.exists(dirname):
             util.makedirs(dirname, self.createmode)
 
         if self._can_symlink:
             try:
                 os.symlink(src, linkname)
             except OSError, err:
                 raise OSError(err.errno, _('could not symlink to %r: %s') %
                               (src, err.strerror), linkname)
         else:
             f = self(dst, "w")
             f.write(src)
             f.close()
             self._fixfilemode(dst)
 
 def canonpath(root, cwd, myname, auditor=None):
     '''return the canonical path of myname, given cwd and root'''
     if util.endswithsep(root):
         rootsep = root
     else:
         rootsep = root + os.sep
     name = myname
     if not os.path.isabs(name):
         name = os.path.join(root, cwd, name)
     name = os.path.normpath(name)
     if auditor is None:
         auditor = path_auditor(root)
     if name != rootsep and name.startswith(rootsep):
         name = name[len(rootsep):]
         auditor(name)
         return util.pconvert(name)
     elif name == root:
         return ''
     else:
         # Determine whether `name' is in the hierarchy at or beneath `root',
         # by iterating name=dirname(name) until that causes no change (can't
         # check name == '/', because that doesn't work on windows).  For each
         # `name', compare dev/inode numbers.  If they match, the list `rel'
         # holds the reversed list of components making up the relative file
         # name we want.
         root_st = os.stat(root)
         rel = []
         while True:
             try:
                 name_st = os.stat(name)
             except OSError:
                 break
             if util.samestat(name_st, root_st):
                 if not rel:
                     # name was actually the same as root (maybe a symlink)
                     return ''
                 rel.reverse()
                 name = os.path.join(*rel)
                 auditor(name)
                 return util.pconvert(name)
             dirname, basename = os.path.split(name)
             rel.append(basename)
             if dirname == name:
                 break
             name = dirname
 
         raise util.Abort('%s not under root' % myname)
 
 def walkrepos(path, followsym=False, seen_dirs=None, recurse=False):
     '''yield every hg repository under path, recursively.'''
     def errhandler(err):
         if err.filename == path:
             raise err
     if followsym and hasattr(os.path, 'samestat'):
         def _add_dir_if_not_there(dirlst, dirname):
             match = False
             samestat = os.path.samestat
             dirstat = os.stat(dirname)
             for lstdirstat in dirlst:
                 if samestat(dirstat, lstdirstat):
                     match = True
                     break
             if not match:
                 dirlst.append(dirstat)
             return not match
     else:
         followsym = False
 
     if (seen_dirs is None) and followsym:
         seen_dirs = []
         _add_dir_if_not_there(seen_dirs, path)
     for root, dirs, files in os.walk(path, topdown=True, onerror=errhandler):
         dirs.sort()
         if '.hg' in dirs:
             yield root # found a repository
             qroot = os.path.join(root, '.hg', 'patches')
             if os.path.isdir(os.path.join(qroot, '.hg')):
                 yield qroot # we have a patch queue repo here
             if recurse:
                 # avoid recursing inside the .hg directory
                 dirs.remove('.hg')
             else:
                 dirs[:] = [] # don't descend further
         elif followsym:
             newdirs = []
             for d in dirs:
                 fname = os.path.join(root, d)
                 if _add_dir_if_not_there(seen_dirs, fname):
                     if os.path.islink(fname):
                         for hgname in walkrepos(fname, True, seen_dirs):
                             yield hgname
                     else:
                         newdirs.append(d)
             dirs[:] = newdirs
 
 def os_rcpath():
     '''return default os-specific hgrc search path'''
     path = system_rcpath()
     path.extend(user_rcpath())
     path = [os.path.normpath(f) for f in path]
     return path
 
 _rcpath = None
 
 def rcpath():
     '''return hgrc search path. if env var HGRCPATH is set, use it.
     for each item in path, if directory, use files ending in .rc,
     else use item.
     make HGRCPATH empty to only look in .hg/hgrc of current repo.
     if no HGRCPATH, use default os-specific path.'''
     global _rcpath
     if _rcpath is None:
         if 'HGRCPATH' in os.environ:
             _rcpath = []
             for p in os.environ['HGRCPATH'].split(os.pathsep):
                 if not p:
                     continue
                 p = util.expandpath(p)
                 if os.path.isdir(p):
                     for f, kind in osutil.listdir(p):
                         if f.endswith('.rc'):
                             _rcpath.append(os.path.join(p, f))
                 else:
                     _rcpath.append(p)
         else:
             _rcpath = os_rcpath()
     return _rcpath
 
 if os.name != 'nt':
 
     def rcfiles(path):
         rcs = [os.path.join(path, 'hgrc')]
         rcdir = os.path.join(path, 'hgrc.d')
         try:
             rcs.extend([os.path.join(rcdir, f)
                         for f, kind in osutil.listdir(rcdir)
                         if f.endswith(".rc")])
         except OSError:
             pass
         return rcs
 
     def system_rcpath():
         path = []
         # old mod_python does not set sys.argv
         if len(getattr(sys, 'argv', [])) > 0:
             path.extend(rcfiles(os.path.dirname(sys.argv[0]) +
                                   '/../etc/mercurial'))
         path.extend(rcfiles('/etc/mercurial'))
         return path
 
     def user_rcpath():
         return [os.path.expanduser('~/.hgrc')]
 
 else:
 
     _HKEY_LOCAL_MACHINE = 0x80000002L
 
     def system_rcpath():
         '''return default os-specific hgrc search path'''
         rcpath = []
         filename = util.executable_path()
         # Use mercurial.ini found in directory with hg.exe
         progrc = os.path.join(os.path.dirname(filename), 'mercurial.ini')
         if os.path.isfile(progrc):
             rcpath.append(progrc)
             return rcpath
         # Use hgrc.d found in directory with hg.exe
         progrcd = os.path.join(os.path.dirname(filename), 'hgrc.d')
         if os.path.isdir(progrcd):
             for f, kind in osutil.listdir(progrcd):
                 if f.endswith('.rc'):
                     rcpath.append(os.path.join(progrcd, f))
             return rcpath
         # else look for a system rcpath in the registry
         value = util.lookup_reg('SOFTWARE\\Mercurial', None,
                                 _HKEY_LOCAL_MACHINE)
         if not isinstance(value, str) or not value:
             return rcpath
         value = value.replace('/', os.sep)
         for p in value.split(os.pathsep):
             if p.lower().endswith('mercurial.ini'):
                 rcpath.append(p)
             elif os.path.isdir(p):
                 for f, kind in osutil.listdir(p):
                     if f.endswith('.rc'):
                         rcpath.append(os.path.join(p, f))
         return rcpath
 
     def user_rcpath():
         '''return os-specific hgrc search path to the user dir'''
         home = os.path.expanduser('~')
         path = [os.path.join(home, 'mercurial.ini'),
                 os.path.join(home, '.hgrc')]
         userprofile = os.environ.get('USERPROFILE')
         if userprofile:
             path.append(os.path.join(userprofile, 'mercurial.ini'))
             path.append(os.path.join(userprofile, '.hgrc'))
         return path