file_util.py 文件源码

def _copy_file_contents(src, dst, buffer_size=16*1024):
    """Copy the file 'src' to 'dst'.

    Both must be filenames. Any error opening either file, reading from
    'src', or writing to 'dst', raises DistutilsFileError.  Data is
    read/written in chunks of 'buffer_size' bytes (default 16k).  No attempt
    is made to handle anything apart from regular files.
    """
    # Stolen from shutil module in the standard library, but with
    # custom error-handling added.
    fsrc = None
    fdst = None
    try:
        try:
            fsrc = open(src, 'rb')
        except os.error, (errno, errstr):
            raise DistutilsFileError("could not open '%s': %s" % (src, errstr))

        if os.path.exists(dst):
            try:
                os.unlink(dst)
            except os.error, (errno, errstr):
                raise DistutilsFileError(
                      "could not delete '%s': %s" % (dst, errstr))

        try:
            fdst = open(dst, 'wb')
        except os.error, (errno, errstr):
            raise DistutilsFileError(
                  "could not create '%s': %s" % (dst, errstr))

        while 1:
            try:
                buf = fsrc.read(buffer_size)
            except os.error, (errno, errstr):
                raise DistutilsFileError(
                      "could not read from '%s': %s" % (src, errstr))

            if not buf:
                break

            try:
                fdst.write(buf)
            except os.error, (errno, errstr):
                raise DistutilsFileError(
                      "could not write to '%s': %s" % (dst, errstr))

    finally:
        if fdst:
            fdst.close()
        if fsrc:
            fsrc.close()