comparison mercurial/util.py @ 34295:3bb2a9f25fe9

util: add an mmapread method

This is useful for large files that are only partly touched.

Test Plan:
Will be used and tested in a later patch.

Differential Revision: https://phab.mercurial-scm.org/D476

34294:05131c963767

import datetime
import errno
import gc
import hashlib
import imp
import os
import platform as pyplatform
import re as remod
import shutil
import signal

        if not data:
            self._eof = True
        else:
            self._lenbuf += len(data)
            self._buffer.append(data)

def popen2(cmd, env=None, newlines=False):
    # Setting bufsize to -1 lets the system decide the buffer size.
    # The default for bufsize is 0, meaning unbuffered. This leads to
    # poor performance on Mac OS X: http://bugs.python.org/issue4194

34295:3bb2a9f25fe9

import datetime
import errno
import gc
import hashlib
import imp
import mmap
import os
import platform as pyplatform
import re as remod
import shutil
import signal

        if not data:
            self._eof = True
        else:
            self._lenbuf += len(data)
            self._buffer.append(data)

def mmapread(fp):
    try:
        fd = getattr(fp, 'fileno', lambda: fp)()
        return mmap.mmap(fd, 0, access=mmap.ACCESS_READ)
    except ValueError:
        # Empty files cannot be mmapped, but mmapread should still work.  Check
        # if the file is empty, and if so, return an empty buffer.
        if os.fstat(fd).st_size == 0:
            return ''
        raise

def popen2(cmd, env=None, newlines=False):
    # Setting bufsize to -1 lets the system decide the buffer size.
    # The default for bufsize is 0, meaning unbuffered. This leads to
    # poor performance on Mac OS X: http://bugs.python.org/issue4194