util: add realpath() for getting the 'true' path.

The function is implemented for Mac OS X using the F_GETPATH fcntl,
and a basic implementation for Windows is provided as well. On other
POSIX systems, vanilla os.path.realpath() is used.

mercurial/posix.py

@@ -1,214 +1,252 b''
 # posix.py - Posix utility function implementations for Mercurial
 #
 #  Copyright 2005-2009 Matt Mackall <[e-mail]> and others
 #
 # This software may be used and distributed according to the terms of the
 # GNU General Public License version 2, incorporated herein by reference.
 
 from i18n import _
 import osutil
-import os, sys, errno, stat, getpass, pwd, grp
+import os, sys, errno, stat, getpass, pwd, grp, fcntl
 
 posixfile = open
 nulldev = '/dev/null'
 normpath = os.path.normpath
 samestat = os.path.samestat
 expandglobs = False
 
 umask = os.umask(0)
 os.umask(umask)
 
 def openhardlinks():
     '''return true if it is safe to hold open file handles to hardlinks'''
     return True
 
 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')]
 
 def parse_patch_output(output_line):
     """parses the output produced by patch and returns the filename"""
     pf = output_line[14:]
     if os.sys.platform == 'OpenVMS':
         if pf[0] == '`':
             pf = pf[1:-1] # Remove the quotes
     else:
         if pf.startswith("'") and pf.endswith("'") and " " in pf:
             pf = pf[1:-1] # Remove the quotes
     return pf
 
 def sshargs(sshcmd, host, user, port):
     '''Build argument list for ssh'''
     args = user and ("%s@%s" % (user, host)) or host
     return port and ("%s -p %s" % (args, port)) or args
 
 def is_exec(f):
     """check whether a file is executable"""
     return (os.lstat(f).st_mode & 0100 != 0)
 
 def set_flags(f, l, x):
     s = os.lstat(f).st_mode
     if l:
         if not stat.S_ISLNK(s):
             # switch file to link
             data = open(f).read()
             os.unlink(f)
             try:
                 os.symlink(data, f)
             except:
                 # failed to make a link, rewrite file
                 open(f, "w").write(data)
         # no chmod needed at this point
         return
     if stat.S_ISLNK(s):
         # switch link to file
         data = os.readlink(f)
         os.unlink(f)
         open(f, "w").write(data)
         s = 0666 & ~umask # avoid restatting for chmod
 
     sx = s & 0100
     if x and not sx:
         # Turn on +x for every +r bit when making a file executable
         # and obey umask.
         os.chmod(f, s | (s & 0444) >> 2 & ~umask)
     elif not x and sx:
         # Turn off all +x bits
         os.chmod(f, s & 0666)
 
 def set_binary(fd):
     pass
 
 def pconvert(path):
     return path
 
 def localpath(path):
     return path
 
+if sys.platform == 'darwin':
+    def realpath(path):
+        '''
+        Returns the true, canonical file system path equivalent to the given
+        path.
+
+        Equivalent means, in this case, resulting in the same, unique
+        file system link to the path. Every file system entry, whether a file,
+        directory, hard link or symbolic link or special, will have a single
+        path preferred by the system, but may allow multiple, differing path
+        lookups to point to it.
+
+        Most regular UNIX file systems only allow a file system entry to be
+        looked up by its distinct path. Obviously, this does not apply to case
+        insensitive file systems, whether case preserving or not. The most
+        complex issue to deal with is file systems transparently reencoding the
+        path, such as the non-standard Unicode normalisation required for HFS+
+        and HFSX.
+        '''
+        # Constants copied from /usr/include/sys/fcntl.h
+        F_GETPATH = 50
+        O_SYMLINK = 0x200000
+
+        try:
+            fd = os.open(path, O_SYMLINK)
+        except OSError, err:
+            if err.errno is errno.ENOENT:
+                return path
+            raise
+
+        try:
+            return fcntl.fcntl(fd, F_GETPATH, '\0' * 1024).rstrip('\0')
+        finally:
+            os.close(fd)
+else:
+    # Fallback to the likely inadequate Python builtin function.
+    realpath = os.path.realpath
+
 def shellquote(s):
     if os.sys.platform == 'OpenVMS':
         return '"%s"' % s
     else:
         return "'%s'" % s.replace("'", "'\\''")
 
 def quotecommand(cmd):
     return cmd
 
 def popen(command, mode='r'):
     return os.popen(command, mode)
 
 def testpid(pid):
     '''return False if pid dead, True if running or not sure'''
     if os.sys.platform == 'OpenVMS':
         return True
     try:
         os.kill(pid, 0)
         return True
     except OSError, inst:
         return inst.errno != errno.ESRCH
 
 def explain_exit(code):
     """return a 2-tuple (desc, code) describing a process's status"""
     if os.WIFEXITED(code):
         val = os.WEXITSTATUS(code)
         return _("exited with status %d") % val, val
     elif os.WIFSIGNALED(code):
         val = os.WTERMSIG(code)
         return _("killed by signal %d") % val, val
     elif os.WIFSTOPPED(code):
         val = os.WSTOPSIG(code)
         return _("stopped by signal %d") % val, val
     raise ValueError(_("invalid exit code"))
 
 def isowner(st):
     """Return True if the stat object st is from the current user."""
     return st.st_uid == os.getuid()
 
 def find_exe(command):
     '''Find executable for command searching like which does.
     If command is a basename then PATH is searched for command.
     PATH isn't searched if command is an absolute or relative path.
     If command isn't found None is returned.'''
     if sys.platform == 'OpenVMS':
         return command
 
     def findexisting(executable):
         'Will return executable if existing file'
         if os.path.exists(executable):
             return executable
         return None
 
     if os.sep in command:
         return findexisting(command)
 
     for path in os.environ.get('PATH', '').split(os.pathsep):
         executable = findexisting(os.path.join(path, command))
         if executable is not None:
             return executable
     return None
 
 def set_signal_handler():
     pass
 
 def statfiles(files):
     'Stat each file in files and yield stat or None if file does not exist.'
     lstat = os.lstat
     for nf in files:
         try:
             st = lstat(nf)
         except OSError, err:
             if err.errno not in (errno.ENOENT, errno.ENOTDIR):
                 raise
             st = None
         yield st
 
 def getuser():
     '''return name of current user'''
     return getpass.getuser()
 
 def expand_glob(pats):
     '''On Windows, expand the implicit globs in a list of patterns'''
     return list(pats)
 
 def username(uid=None):
     """Return the name of the user with the given uid.
 
     If uid is None, return the name of the current user."""
 
     if uid is None:
         uid = os.getuid()
     try:
         return pwd.getpwuid(uid)[0]
     except KeyError:
         return str(uid)
 
 def groupname(gid=None):
     """Return the name of the group with the given gid.
 
     If gid is None, return the name of the current group."""
 
     if gid is None:
         gid = os.getgid()
     try:
         return grp.getgrgid(gid)[0]
     except KeyError:
         return str(gid)

mercurial/windows.py

@@ -1,283 +1,292 b''
 # windows.py - Windows utility function implementations for Mercurial
 #
 #  Copyright 2005-2009 Matt Mackall <[e-mail]> and others
 #
 # This software may be used and distributed according to the terms of the
 # GNU General Public License version 2, incorporated herein by reference.
 
 from i18n import _
 import osutil, error
 import errno, msvcrt, os, re, sys
 
 nulldev = 'NUL:'
 umask = 002
 
 # wrap osutil.posixfile to provide friendlier exceptions
 def posixfile(name, mode='r', buffering=-1):
     try:
         return osutil.posixfile(name, mode, buffering)
     except WindowsError, err:
         raise IOError(err.errno, err.strerror)
 posixfile.__doc__ = osutil.posixfile.__doc__
 
 class winstdout(object):
     '''stdout on windows misbehaves if sent through a pipe'''
 
     def __init__(self, fp):
         self.fp = fp
 
     def __getattr__(self, key):
         return getattr(self.fp, key)
 
     def close(self):
         try:
             self.fp.close()
         except: pass
 
     def write(self, s):
         try:
             # This is workaround for "Not enough space" error on
             # writing large size of data to console.
             limit = 16000
             l = len(s)
             start = 0
             self.softspace = 0;
             while start < l:
                 end = start + limit
                 self.fp.write(s[start:end])
                 start = end
         except IOError, inst:
             if inst.errno != 0: raise
             self.close()
             raise IOError(errno.EPIPE, 'Broken pipe')
 
     def flush(self):
         try:
             return self.fp.flush()
         except IOError, inst:
             if inst.errno != errno.EINVAL: raise
             self.close()
             raise IOError(errno.EPIPE, 'Broken pipe')
 
 sys.stdout = winstdout(sys.stdout)
 
 def _is_win_9x():
     '''return true if run on windows 95, 98 or me.'''
     try:
         return sys.getwindowsversion()[3] == 1
     except AttributeError:
         return 'command' in os.environ.get('comspec', '')
 
 def openhardlinks():
     return not _is_win_9x() and "win32api" in globals()
 
 def system_rcpath():
     try:
         return system_rcpath_win32()
     except:
         return [r'c:\mercurial\mercurial.ini']
 
 def user_rcpath():
     '''return os-specific hgrc search path to the user dir'''
     try:
         path = user_rcpath_win32()
     except:
         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
 
 def parse_patch_output(output_line):
     """parses the output produced by patch and returns the filename"""
     pf = output_line[14:]
     if pf[0] == '`':
         pf = pf[1:-1] # Remove the quotes
     return pf
 
 def sshargs(sshcmd, host, user, port):
     '''Build argument list for ssh or Plink'''
     pflag = 'plink' in sshcmd.lower() and '-P' or '-p'
     args = user and ("%s@%s" % (user, host)) or host
     return port and ("%s %s %s" % (args, pflag, port)) or args
 
 def testpid(pid):
     '''return False if pid dead, True if running or not known'''
     return True
 
 def set_flags(f, l, x):
     pass
 
 def set_binary(fd):
     # When run without console, pipes may expose invalid
     # fileno(), usually set to -1.
     if hasattr(fd, 'fileno') and fd.fileno() >= 0:
         msvcrt.setmode(fd.fileno(), os.O_BINARY)
 
 def pconvert(path):
     return '/'.join(path.split(os.sep))
 
 def localpath(path):
     return path.replace('/', '\\')
 
 def normpath(path):
     return pconvert(os.path.normpath(path))
 
+def realpath(path):
+    '''
+    Returns the true, canonical file system path equivalent to the given
+    path.
+    '''
+    # TODO: There may be a more clever way to do this that also handles other,
+    # less common file systems.
+    return os.path.normpath(os.path.normcase(os.path.realpath(path)))
+
 def samestat(s1, s2):
     return False
 
 # A sequence of backslashes is special iff it precedes a double quote:
 # - if there's an even number of backslashes, the double quote is not
 #   quoted (i.e. it ends the quoted region)
 # - if there's an odd number of backslashes, the double quote is quoted
 # - in both cases, every pair of backslashes is unquoted into a single
 #   backslash
 # (See http://msdn2.microsoft.com/en-us/library/a1y7w461.aspx )
 # So, to quote a string, we must surround it in double quotes, double
 # the number of backslashes that preceed double quotes and add another
 # backslash before every double quote (being careful with the double
 # quote we've appended to the end)
 _quotere = None
 def shellquote(s):
     global _quotere
     if _quotere is None:
         _quotere = re.compile(r'(\\*)("|\\$)')
     return '"%s"' % _quotere.sub(r'\1\1\\\2', s)
 
 def quotecommand(cmd):
     """Build a command string suitable for os.popen* calls."""
     # The extra quotes are needed because popen* runs the command
     # through the current COMSPEC. cmd.exe suppress enclosing quotes.
     return '"' + cmd + '"'
 
 def popen(command, mode='r'):
     # Work around "popen spawned process may not write to stdout
     # under windows"
     # http://bugs.python.org/issue1366
     command += " 2> %s" % nulldev
     return os.popen(quotecommand(command), mode)
 
 def explain_exit(code):
     return _("exited with status %d") % code, code
 
 # if you change this stub into a real check, please try to implement the
 # username and groupname functions above, too.
 def isowner(st):
     return True
 
 def find_exe(command):
     '''Find executable for command searching like cmd.exe does.
     If command is a basename then PATH is searched for command.
     PATH isn't searched if command is an absolute or relative path.
     An extension from PATHEXT is found and added if not present.
     If command isn't found None is returned.'''
     pathext = os.environ.get('PATHEXT', '.COM;.EXE;.BAT;.CMD')
     pathexts = [ext for ext in pathext.lower().split(os.pathsep)]
     if os.path.splitext(command)[1].lower() in pathexts:
         pathexts = ['']
 
     def findexisting(pathcommand):
         'Will append extension (if needed) and return existing file'
         for ext in pathexts:
             executable = pathcommand + ext
             if os.path.exists(executable):
                 return executable
         return None
 
     if os.sep in command:
         return findexisting(command)
 
     for path in os.environ.get('PATH', '').split(os.pathsep):
         executable = findexisting(os.path.join(path, command))
         if executable is not None:
             return executable
     return None
 
 def set_signal_handler():
     try:
         set_signal_handler_win32()
     except NameError:
         pass
 
 def statfiles(files):
     '''Stat each file in files and yield stat or None if file does not exist.
     Cluster and cache stat per directory to minimize number of OS stat calls.'''
     ncase = os.path.normcase
     sep   = os.sep
     dircache = {} # dirname -> filename -> status | None if file does not exist
     for nf in files:
         nf  = ncase(nf)
         dir, base = os.path.split(nf)
         if not dir:
             dir = '.'
         cache = dircache.get(dir, None)
         if cache is None:
             try:
                 dmap = dict([(ncase(n), s)
                     for n, k, s in osutil.listdir(dir, True)])
             except OSError, err:
                 # handle directory not found in Python version prior to 2.5
                 # Python <= 2.4 returns native Windows code 3 in errno
                 # Python >= 2.5 returns ENOENT and adds winerror field
                 # EINVAL is raised if dir is not a directory.
                 if err.errno not in (3, errno.ENOENT, errno.EINVAL,
                                      errno.ENOTDIR):
                     raise
                 dmap = {}
             cache = dircache.setdefault(dir, dmap)
         yield cache.get(base, None)
 
 def getuser():
     '''return name of current user'''
     raise error.Abort(_('user name not available - set USERNAME '
                        'environment variable'))
 
 def username(uid=None):
     """Return the name of the user with the given uid.
 
     If uid is None, return the name of the current user."""
     return None
 
 def groupname(gid=None):
     """Return the name of the group with the given gid.
 
     If gid is None, return the name of the current group."""
     return None
 
 def _removedirs(name):
     """special version of os.removedirs that does not remove symlinked
     directories or junction points if they actually contain files"""
     if osutil.listdir(name):
         return
     os.rmdir(name)
     head, tail = os.path.split(name)
     if not tail:
         head, tail = os.path.split(head)
     while head and tail:
         try:
             if osutil.listdir(name):
                 return
             os.rmdir(head)
         except:
             break
         head, tail = os.path.split(head)
 
 def unlink(f):
     """unlink and remove the directory if it is empty"""
     os.unlink(f)
     # try removing directories that might now be empty
     try:
         _removedirs(os.path.dirname(f))
     except OSError:
         pass
 
 try:
     # override functions with win32 versions if possible
     from win32 import *
 except ImportError:
     pass
 
 expandglobs = True