mercurial/util.py
author Bryan O'Sullivan <bos@serpentine.com>
Fri, 29 Jul 2005 12:30:12 -0800
changeset 812 b65af904d6d7
parent 782 cdb9e95b2fab
child 814 0902ffece4b4
permissions -rw-r--r--
Reduce the amount of stat traffic generated by a walk. When we switched to the new walk code for commands, we no longer passed a list of specific files to the repo or dirstate walk or changes methods. This meant that we always walked and attempted to match everything, which was not efficient. Now, if we are given any patterns to match, or nothing at all, we still walk everything. But if we are given only file names that contain no glob characters, we only walk those.

# util.py - utility functions and platform specfic implementations
#
# Copyright 2005 K. Thananchayan <thananck@yahoo.com>
#
# This software may be used and distributed according to the terms
# of the GNU General Public License, incorporated herein by reference.

import os, errno
from demandload import *
demandload(globals(), "re")

def unique(g):
    seen = {}
    for f in g:
        if f not in seen:
            seen[f] = 1
            yield f

class CommandError(Exception): pass

def always(fn): return True
def never(fn): return False

def globre(pat, head = '^', tail = '$'):
    "convert a glob pattern into a regexp"
    i, n = 0, len(pat)
    res = ''
    group = False
    def peek(): return i < n and pat[i]
    while i < n:
        c = pat[i]
        i = i+1
        if c == '*':
            if peek() == '*':
                i += 1
                res += '.*'
            else:
                res += '[^/]*'
        elif c == '?':
            res += '.'
        elif c == '[':
            j = i
            if j < n and pat[j] in '!]':
                j += 1
            while j < n and pat[j] != ']':
                j += 1
            if j >= n:
                res += '\\['
            else:
                stuff = pat[i:j].replace('\\','\\\\')
                i = j + 1
                if stuff[0] == '!':
                    stuff = '^' + stuff[1:]
                elif stuff[0] == '^':
                    stuff = '\\' + stuff
                res = '%s[%s]' % (res, stuff)
        elif c == '{':
            group = True
            res += '(?:'
        elif c == '}' and group:
            res += ')'
            group = False
        elif c == ',' and group:
            res += '|'
        else:
            res += re.escape(c)
    return head + res + tail

_globchars = {'[': 1, '{': 1, '*': 1, '?': 1}

def matcher(cwd, names, inc, exc, head = ''):
    def patlike(name):
        for prefix in 're:', 'glob:', 'path:':
            if name.startswith(prefix): return True
        for c in name:
            if c in _globchars: return True

    def regex(name, tail):
        '''convert a pattern into a regular expression'''
        if name.startswith('re:'):
            return name[3:]
        elif name.startswith('path:'):
            return '^' + re.escape(name[5:]) + '$'
        elif name.startswith('glob:'):
            return head + globre(name[5:], '', tail)
        return head + globre(name, '', tail)

    cwdsep = cwd + os.sep

    def under(fn):
        """check if fn is under our cwd"""
        return not cwd or fn.startswith(cwdsep)

    def matchfn(pats, tail):
        """build a matching function from a set of patterns"""
        if pats:
            pat = '(?:%s)' % '|'.join([regex(p, tail) for p in pats])
            if cwd:
                pat = re.escape(cwdsep) + pat
            return re.compile(pat).match

    pats = filter(patlike, names)
    files = [n for n in names if not patlike(n)]
    if pats: plain = []
    elif cwd: plain = [cwdsep + f for f in files]
    else: plain = files
        
    patmatch = matchfn(pats, '$')
    filematch = matchfn(files, '(?:/|$)')
    incmatch = matchfn(inc, '(?:/|$)') or under
    excmatch = matchfn(exc, '(?:/|$)') or (lambda fn: False)

    return plain, lambda fn: (incmatch(fn) and not excmatch(fn) and
                              (fn.endswith('/') or
                               (not pats and not files) or
                               (pats and patmatch(fn)) or
                               (files and filematch(fn))))

def system(cmd, errprefix=None):
    """execute a shell command that must succeed"""
    rc = os.system(cmd)
    if rc:
        errmsg = "%s %s" % (os.path.basename(cmd.split(None, 1)[0]),
                            explain_exit(rc)[0])
        if errprefix:
            errmsg = "%s: %s" % (errprefix, errmsg)
        raise CommandError(errmsg)

def rename(src, dst):
    try:
        os.rename(src, dst)
    except:
        os.unlink(dst)
        os.rename(src, dst)

def copytree(src, dst, copyfile):
    """Copy a directory tree, files are copied using 'copyfile'."""
    names = os.listdir(src)
    os.mkdir(dst)

    for name in names:
        srcname = os.path.join(src, name)
        dstname = os.path.join(dst, name)
        if os.path.isdir(srcname):
            copytree(srcname, dstname, copyfile)
        elif os.path.isfile(srcname):
            copyfile(srcname, dstname)
        else:
            raise IOError("Not a regular file: %r" % srcname)

def _makelock_file(info, pathname):
    ld = os.open(pathname, os.O_CREAT | os.O_WRONLY | os.O_EXCL)
    os.write(ld, info)
    os.close(ld)

def _readlock_file(pathname):
    return file(pathname).read()

# Platfor specific varients
if os.name == 'nt':
    nulldev = 'NUL:'

    def is_exec(f, last):
        return last

    def set_exec(f, mode):
        pass

    def pconvert(path):
        return path.replace("\\", "/")

    makelock = _makelock_file
    readlock = _readlock_file

    def explain_exit(code):
        return "exited with status %d" % code, code

else:
    nulldev = '/dev/null'

    def is_exec(f, last):
        return (os.stat(f).st_mode & 0100 != 0)

    def set_exec(f, mode):
        s = os.stat(f).st_mode
        if (s & 0100 != 0) == mode:
            return
        if mode:
            # Turn on +x for every +r bit when making a file executable
            # and obey umask.
            umask = os.umask(0)
            os.umask(umask)
            os.chmod(f, s | (s & 0444) >> 2 & ~umask)
        else:
            os.chmod(f, s & 0666)

    def pconvert(path):
        return path

    def makelock(info, pathname):
        try:
            os.symlink(info, pathname)
        except OSError, why:
            if why.errno == errno.EEXIST:
                raise
            else:
                _makelock_file(info, pathname)

    def readlock(pathname):
        try:
            return os.readlink(pathname)
        except OSError, why:
            if why.errno == errno.EINVAL:
                return _readlock_file(pathname)
            else:
                raise

    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.STOPSIG(code)
            return "stopped by signal %d" % val, val
        raise ValueError("invalid exit code")