diff options
| -rw-r--r-- | libpipe/pipe.h | 85 |
1 files changed, 71 insertions, 14 deletions
diff --git a/libpipe/pipe.h b/libpipe/pipe.h index f9ea243b..677e0356 100644 --- a/libpipe/pipe.h +++ b/libpipe/pipe.h @@ -73,7 +73,17 @@ struct pipe time_value_t write_time; struct condition pending_reads; - struct condition pending_selects; + struct condition pending_read_selects; + + struct condition pending_writes; + struct condition pending_write_selects; + + /* The maximum number of characters that this pipe will hold without + further writes blocking. */ + size_t write_limit; + + /* Write requests of less than this much are always done atomically. */ + size_t write_atomic; struct mutex lock; @@ -127,7 +137,7 @@ pipe_is_readable (struct pipe *pipe, int data_only) immediately available. If DATA_ONLY is true, then `control' packets are ignored. */ extern inline error_t -pipe_wait (struct pipe *pipe, int noblock, int data_only) +pipe_wait_readable (struct pipe *pipe, int noblock, int data_only) { while (! pipe_is_readable (pipe, data_only) && ! (pipe->flags & PIPE_BROKEN)) { @@ -140,20 +150,51 @@ pipe_wait (struct pipe *pipe, int noblock, int data_only) } /* Waits for PIPE to be readable, or an error to occurr. This call only - returns once threads waiting using pipe_wait have been woken and given a - chance to read, and if there is still data available thereafter. If - DATA_ONLY is true, then `control' packets are ignored. */ + returns once threads waiting using pipe_wait_readable have been woken and + given a chance to read, and if there is still data available thereafter. + If DATA_ONLY is true, then `control' packets are ignored. */ extern inline error_t -pipe_select (struct pipe *pipe, int data_only) +pipe_select_readable (struct pipe *pipe, int data_only) { while (! pipe_is_readable (pipe, data_only) && ! (pipe->flags & PIPE_BROKEN)) - if (hurd_condition_wait (&pipe->pending_selects, &pipe->lock)) + if (hurd_condition_wait (&pipe->pending_read_selects, &pipe->lock)) + return EINTR; + return 0; +} + +/* Block until data can be written to PIPE. If NOBLOCK is true, then + EWOULDBLOCK is returned instead of blocking if this can't be done + immediately. */ +extern inline error_t +pipe_wait_writable (struct pipe *pipe, int noblock) +{ + size_t limit = pipe->write_limit; + if (pipe->flags & PIPE_BROKEN) + return EPIPE; + while (pipe_readable (pipe, 1) >= limit) + { + if (noblock) + return EWOULDBLOCK; + if (hurd_condition_wait (&pipe->pending_writes, &pipe->lock)) return EINTR; + if (pipe->flags & PIPE_BROKEN) + return EPIPE; + } return 0; } -/* Wake up all threads waiting on PIPE, which should be locked. */ -void pipe_kick (struct pipe *pipe); +/* Block until some data can be written to PIPE. This call only returns once + threads waiting using pipe_wait_writable have been woken and given a + chance to write, and if there is still space available thereafter. */ +extern inline error_t +pipe_select_writable (struct pipe *pipe) +{ + size_t limit = pipe->write_limit; + while (! (pipe->flags & PIPE_BROKEN) && pipe_readable (pipe, 1) >= limit) + if (hurd_condition_wait (&pipe->pending_writes, &pipe->lock)) + return EINTR; + return 0; +} /* Creates a new pipe of class CLASS and returns it in RESULT. */ error_t pipe_create (struct pipe_class *class, struct pipe **pipe); @@ -161,7 +202,10 @@ error_t pipe_create (struct pipe_class *class, struct pipe **pipe); /* Free PIPE and any resources it holds. */ void pipe_free (struct pipe *pipe); -/* Take any actions necessary when PIPE acquires its first writer. */ +/* Take any actions necessary when PIPE acquires its first reader. */ +void _pipe_first_reader (struct pipe *pipe); + +/* Take any actions necessary when PIPE acquires its first writer. */ void _pipe_first_writer (struct pipe *pipe); /* Take any actions necessary when PIPE's last reader has gone away. PIPE @@ -177,7 +221,8 @@ extern inline void pipe_acquire_reader (struct pipe *pipe) { mutex_lock (&pipe->lock); - pipe->readers++; + if (pipe->readers++ == 0) + _pipe_first_reader (pipe); } /* Lock PIPE and increment its writers count. */ @@ -258,7 +303,7 @@ pipe_drain (struct pipe *pipe) returned, nothing is done. If non-NULL, SOURCE is recorded as the source of the data, to be provided to any readers of it; if no reader ever reads it, it's deallocated by calling pipe_dealloc_addr. */ -error_t pipe_send (struct pipe *pipe, void *source, +error_t pipe_send (struct pipe *pipe, int noblock, void *source, char *data, size_t data_len, char *control, size_t control_len, mach_port_t *ports, size_t num_ports, @@ -269,8 +314,8 @@ error_t pipe_send (struct pipe *pipe, void *source, done. If non-NULL, SOURCE is recorded as the source of the data, to be provided to any readers of it; if no reader ever reads it, it's deallocated by calling pipe_dealloc_addr. */ -#define pipe_write(pipe, source, data, data_len, amount) \ - pipe_send (pipe, source, data, data_len, 0, 0, 0, 0, amount) +#define pipe_write(pipe, noblock, source, data, data_len, amount) \ + pipe_send (pipe, noblock, source, data, data_len, 0, 0, 0, 0, amount) /* Reads up to AMOUNT bytes from PIPE, which should be locked, into DATA, and returns the amount read in DATA_LEN. If NOBLOCK is true, EWOULDBLOCK is @@ -306,6 +351,18 @@ error_t pipe_recv (struct pipe *pipe, int noblock, unsigned *flags, #define pipe_read(pipe, noblock, source, data, data_len, amount) \ pipe_recv (pipe, noblock, 0, source, data, data_len, amount, 0,0,0,0) +/* Hold this lock before attempting to lock multiple pipes. */ +extern struct mutex pipe_multiple_lock; + +/* Return when either RPIPE is available for reading (if SELECT_READ is set + in *SELECT_TYPE), or WPIPE is available for writing (if select_write is + set in *SELECT_TYPE). *SELECT_TYPE is modified to reflect which (or both) + is now available. DATA_ONLY should be true if only data packets should be + waited for on RPIPE. Neither RPIPE or WPIPE should be locked when calling + this function (unlike most pipe functions). */ +error_t pipe_pair_select (struct pipe *rpipe, struct pipe *wpipe, + int *select_type, int data_only); + /* ---------------------------------------------------------------- */ /* User-provided functions. */ |