file_io.py 文件源码

def _do_io(self, **kwargs):
        """Read or write to the given file descriptor"""
        fd       = kwargs.pop("fd", None)
        write    = kwargs.pop("write", False)
        offset   = kwargs.pop("offset", 0)
        size     = kwargs.pop("size", 0)
        fileobj  = kwargs.pop("fileobj", None)
        lockfull = kwargs.pop("lockfull", True)
        lockout  = None

        if self.iodelay > 0.0:
            time.sleep(self.iodelay)

        # Set file offset to read/write
        os.lseek(fd, offset, os.SEEK_SET)

        if write:
            if self.random and not lockfull:
                # Lock file segment
                lockout = self._getlock(fileobj.name, fd, lock_type=fcntl.F_WRLCK, offset=offset, length=size)
            data = 'x' * size
            self._dprint("DBG5", "WRITE   %s %d @ %d" % (fileobj.name, size, offset))

            if self.direct:
                # Direct I/O -- use native write function
                count = self.libc.write(fd, self.wbuffer, size)
            else:
                # Buffered I/O
                count = os.write(fd, data)
                if self._percent(self.fsync):
                    self._dprint("DBG4", "FSYNC   %s" % fileobj.name)
                    self.nfsync += 1
                    os.fsync(fd)

            self.nwrite += 1
            self.wbytes += count
            fsize = offset + count
            if fileobj.size < fsize:
                fileobj.size = fsize
        else:
            if self.random and not lockfull:
                # Lock file segment
                lockout = self._getlock(fileobj.name, fd, lock_type=fcntl.F_RDLCK, offset=offset, length=size)
            self._dprint("DBG5", "READ    %s %d @ %d" % (fileobj.name, size, offset))

            if self.direct:
                # Direct I/O -- use native read function
                count = self.libc.read(fd, self.rbuffer, size)
            else:
                # Buffered I/O
                data = os.read(fd, size)
                count = len(data)
            self.rbytes += count
            self.nread += 1

        if self.random and not lockfull:
            # Unlock file segment
            self._getlock(fileobj.name, fd, lock_type=fcntl.F_UNLCK, offset=offset, length=size, lock=lockout)
        return count