Created a class in util called chunkbuffer that buffers reads from an
iterator over strings (aka chunks).
Also added to util (for future use) is a generator function that
iterates over a file n bytes at a time.
Lastly, localrepo was changed to use this new chunkbuffer class when
reading changegroups form the local repository.
"""
util.py - Mercurial 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.
This contains helper routines that are independent of the SCM core and hide
platform-specific details from the core.
"""
import os, errno
from demandload import *
demandload(globals(), "re cStringIO")
def binary(s):
"""return true if a string is binary data using diff's heuristic"""
if s and '\0' in s[:4096]:
return True
return False
def unique(g):
"""return the uniq elements of iterable g"""
seen = {}
for f in g:
if f not in seen:
seen[f] = 1
yield f
class Abort(Exception):
"""Raised if a command needs to print an error and exit."""
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 pathto(n1, n2):
'''return the relative path from one place to another.
this returns a path in the form used by the local filesystem, not hg.'''
if not n1: return localpath(n2)
a, b = n1.split('/'), n2.split('/')
a.reverse(), b.reverse()
while a and b and a[-1] == b[-1]:
a.pop(), b.pop()
b.reverse()
return os.sep.join((['..'] * len(a)) + b)
def canonpath(root, cwd, myname):
"""return the canonical path of myname, given cwd and root"""
rootsep = root + os.sep
name = myname
if not name.startswith(os.sep):
name = os.path.join(root, cwd, name)
name = os.path.normpath(name)
if name.startswith(rootsep):
return pconvert(name[len(rootsep):])
elif name == root:
return ''
else:
raise Abort('%s not under root' % myname)
def matcher(canonroot, cwd, names, inc, exc, head=''):
"""build a function to match a set of file patterns
arguments:
canonroot - the canonical root of the tree you're matching against
cwd - the current working directory, if relevant
names - patterns to find
inc - patterns to include
exc - patterns to exclude
head - a regex to prepend to patterns to control whether a match is rooted
a pattern is one of:
're:<regex>'
'glob:<shellglob>'
'path:<explicit path>'
'relpath:<relative path>'
'<relative path>'
returns:
a 3-tuple containing
- list of explicit non-pattern names passed in
- a bool match(filename) function
- a bool indicating if any patterns were passed in
todo:
make head regex a rooted bool
"""
def patkind(name):
for prefix in 're:', 'glob:', 'path:', 'relpath:':
if name.startswith(prefix): return name.split(':', 1)
for c in name:
if c in _globchars: return 'glob', name
return 'relpath', name
def regex(kind, name, tail):
'''convert a pattern into a regular expression'''
if kind == 're':
return name
elif kind == 'path':
return '^' + re.escape(name) + '(?:/|$)'
elif kind == 'relpath':
return head + re.escape(name) + tail
return head + globre(name, '', tail)
def matchfn(pats, tail):
"""build a matching function from a set of patterns"""
if pats:
pat = '(?:%s)' % '|'.join([regex(k, p, tail) for (k, p) in pats])
return re.compile(pat).match
def globprefix(pat):
'''return the non-glob prefix of a path, e.g. foo/* -> foo'''
root = []
for p in pat.split(os.sep):
if patkind(p)[0] == 'glob': break
root.append(p)
return '/'.join(root)
pats = []
files = []
roots = []
for kind, name in map(patkind, names):
if kind in ('glob', 'relpath'):
name = canonpath(canonroot, cwd, name)
if name == '':
kind, name = 'glob', '**'
if kind in ('glob', 'path', 're'):
pats.append((kind, name))
if kind == 'glob':
root = globprefix(name)
if root: roots.append(root)
elif kind == 'relpath':
files.append((kind, name))
roots.append(name)
patmatch = matchfn(pats, '$') or always
filematch = matchfn(files, '(?:/|$)') or always
incmatch = always
if inc:
incmatch = matchfn(map(patkind, inc), '(?:/|$)')
excmatch = lambda fn: False
if exc:
excmatch = matchfn(map(patkind, exc), '(?:/|$)')
return (roots,
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)))),
(inc or exc or (pats and pats != [('glob', '**')])) and True)
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 Abort(errmsg)
def rename(src, dst):
"""forcibly rename a file"""
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:
pass
def opener(base):
"""
return a function that opens files relative to base
this function is used to hide the details of COW semantics and
remote file access from higher level code.
"""
p = base
def o(path, mode="r"):
f = os.path.join(p, path)
mode += "b" # for that other OS
if mode[0] != "r":
try:
s = os.stat(f)
except OSError:
d = os.path.dirname(f)
if not os.path.isdir(d):
os.makedirs(d)
else:
if s.st_nlink > 1:
file(f + ".tmp", "wb").write(file(f, "rb").read())
rename(f+".tmp", f)
return file(f, mode)
return o
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()
# Platform specific variants
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("\\", "/")
def localpath(path):
return path.replace('/', '\\')
def normpath(path):
return pconvert(os.path.normpath(path))
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):
"""check whether a file is executable"""
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 localpath(path):
return path
normpath = os.path.normpath
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.WSTOPSIG(code)
return "stopped by signal %d" % val, val
raise ValueError("invalid exit code")
class chunkbuffer(object):
"""Allow arbitrary sized chunks of data to be efficiently read from an
iterator over chunks of arbitrary size."""
def __init__(self, in_iter, targetsize = 2**16):
"""in_iter is the iterator that's iterating over the input chunks.
targetsize is how big a buffer to try to maintain."""
self.in_iter = iter(in_iter)
self.buf = ''
targetsize = int(targetsize)
if (targetsize <= 0):
raise ValueError("targetsize must be greater than 0, was %d" % targetsize)
self.targetsize = int(targetsize)
self.iterempty = False
def fillbuf(self):
"""x.fillbuf()
Ignore the target size, and just read every chunk from the iterator
until it's empty."""
if not self.iterempty:
collector = cStringIO.StringIO()
collector.write(self.buf)
for ch in self.in_iter:
collector.write(ch)
self.buf = collector.getvalue()
collector.close()
collector = None
self.iterempty = True
def read(self, l):
"""x.read(l) -> str
Read l bytes of data from the iterator of chunks of data. Returns less
than l bytes if the iterator runs dry."""
if l > len(self.buf) and not self.iterempty:
# Clamp to a multiple of self.targetsize
targetsize = self.targetsize * ((l // self.targetsize) + 1)
collector = cStringIO.StringIO()
collector.write(self.buf)
collected = len(self.buf)
for chunk in self.in_iter:
collector.write(chunk)
collected += len(chunk)
if collected >= targetsize:
break
if collected < targetsize:
self.iterempty = True
self.buf = collector.getvalue()
collector.close()
collector = None
s = self.buf[:l]
self.buf = buffer(self.buf, l)
return s
def __repr__(self):
return "<%s.%s targetsize = %u buffered = %u bytes>" % \
(self.__class__.__module__, self.__class__.__name__,
self.targetsize, len(self.buf))
def filechunkiter(f, size = 65536):
"""filechunkiter(file[, size]) -> generator
Create a generator that produces all the data in the file size (default
65536) bytes at a time. Chunks may be less than size bytes if the
chunk is the last chunk in the file, or the file is a socket or some
other type of file that sometimes reads less data than is requested."""
s = f.read(size)
while len(s) >= 0:
yield s
s = f.read(size)