diff options
| -rw-r--r-- | libpipe/pipe.c | 48 |
1 files changed, 33 insertions, 15 deletions
diff --git a/libpipe/pipe.c b/libpipe/pipe.c index a81bdcdc..413b4ec2 100644 --- a/libpipe/pipe.c +++ b/libpipe/pipe.c @@ -43,7 +43,8 @@ pipe_create (struct pipe_class *class, struct pipe **pipe) if (new == NULL) return ENOMEM; - new->refs = 0; + new->readers = 0; + new->writers = 0; new->flags = 0; new->class = class; @@ -68,7 +69,7 @@ pipe_free (struct pipe *pipe) pq_free (pipe->queue); free (pipe); } - + /* Wake up all threads waiting on PIPE, which should be locked. */ inline void pipe_kick (struct pipe *pipe) @@ -80,23 +81,40 @@ pipe_kick (struct pipe *pipe) mutex_lock (&pipe->lock); /* Get back the lock on PIPE. */ } -/* Discard a reference to PIPE, which should be unlocked, being sure to make - users aware of this. */ -void -pipe_break (struct pipe *pipe) +/* Take any actions necessary when PIPE aquires its first writer. */ +void _pipe_first_writer (struct pipe *pipe) { - mutex_lock (&pipe->lock); - - /* As there may be multiple writers on a connectionless socket, we - never allow EOF to be signaled on the reader. */ if (! (pipe->class->flags & PIPE_CLASS_CONNECTIONLESS)) - pipe->flags |= PIPE_BROKEN; + pipe->flags &= ~PIPE_BROKEN; +} - if (pipe->refs > 1) - /* Other references to PIPE besides ours? Wake 'em up. */ - pipe_kick (pipe); +/* Take any actions necessary when PIPE's last reader has gone away. PIPE + should be locked. */ +void _pipe_no_readers (struct pipe *pipe) +{ + if (pipe->writers == 0) + pipe_free (pipe); + else + mutex_unlock (&pipe->lock); +} - pipe_release (pipe); +/* Take any actions necessary when PIPE's last writer has gone away. PIPE + should be locked. */ +void _pipe_no_writers (struct pipe *pipe) +{ + if (pipe->readers == 0) + pipe_free (pipe); + else + { + if (! (pipe->class->flags & PIPE_CLASS_CONNECTIONLESS)) + { + pipe->flags |= PIPE_BROKEN; + if (pipe->readers) + /* Wake up readers who might want to know about our new state. */ + pipe_kick (pipe); + } + mutex_unlock (&pipe->lock); + } } /* Writes up to LEN bytes of DATA, to PIPE, which should be locked, and |