sh.py 文件源码

def write(self):
        """ attempt to get a chunk of data to write to our child process's
        stdin, then write it.  the return value answers the questions "are we
        done writing forever?" """

        # get_chunk may sometimes return bytes, and sometimes return strings
        # because of the nature of the different types of STDIN objects we
        # support
        try:
            chunk = self.get_chunk()
            if chunk is None:
                raise DoneReadingForever

        except DoneReadingForever:
            self.log.debug("done reading")

            if self.tty_in:
                # EOF time
                try:
                    char = termios.tcgetattr(self.stream)[6][termios.VEOF]
                except:
                    char = chr(4).encode()

                # normally, one EOF should be enough to signal to an program
                # that is read()ing, to return 0 and be on your way.  however,
                # some programs are misbehaved, like python3.1 and python3.2.
                # they don't stop reading sometimes after read() returns 0.
                # this can be demonstrated with the following program:
                #
                # import sys
                # sys.stdout.write(sys.stdin.read())
                #
                # then type 'a' followed by ctrl-d 3 times.  in python
                # 2.6,2.7,3.3,3.4,3.5,3.6, it only takes 2 ctrl-d to terminate.
                # however, in python 3.1 and 3.2, it takes all 3.
                #
                # so here we send an extra EOF along, just in case.  i don't
                # believe it can hurt anything
                os.write(self.stream, char)
                os.write(self.stream, char)

            return True

        except NotYetReadyToRead:
            self.log.debug("received no data")
            return False

        # if we're not bytes, make us bytes
        if IS_PY3 and hasattr(chunk, "encode"):
            chunk = chunk.encode(self.encoding)

        for proc_chunk in self.stream_bufferer.process(chunk):
            self.log.debug("got chunk size %d: %r", len(proc_chunk),
                    proc_chunk[:30])

            self.log.debug("writing chunk to process")
            try:
                os.write(self.stream, proc_chunk)
            except OSError:
                self.log.debug("OSError writing stdin chunk")
                return True