From 2415c11dec5e5adb0c17f98aa52fbb371a4f8f23 Mon Sep 17 00:00:00 2001 From: Jamey Sharp Date: Fri, 18 Mar 2011 20:56:07 -0700 Subject: [PATCH 1/1] Introduce xcb_wait_for_event_until, for consuming responses in wire-order. Signed-off-by: Jamey Sharp Reviewed-by: Josh Triplett --- src/xcb.h | 35 +++++++++++++++++++++++++++++++++++ src/xcb_in.c | 45 ++++++++++++++++++++++++++++++++++++++++++--- src/xcbint.h | 2 ++ 3 files changed, 79 insertions(+), 3 deletions(-) diff --git a/src/xcb.h b/src/xcb.h index 14244a7..3e61ebd 100644 --- a/src/xcb.h +++ b/src/xcb.h @@ -271,6 +271,41 @@ xcb_generic_event_t *xcb_wait_for_event(xcb_connection_t *c); */ xcb_generic_event_t *xcb_poll_for_event(xcb_connection_t *c); +/** + * @brief Returns the next event or error that precedes the given request. + * @param c: The connection to the X server. + * @param request: The limiting sequence number. + * @return The next event from the server. + * + * Returns the next event or error with a sequence number less than or + * equal to the given sequence number, or returns NULL if no such event can + * ever arrive. Blocks until either a suitable event or error arrive, or a + * response arrives that proves no such event is coming, or an I/O error + * occurs. + * + * After processing a request, the X server sends responses in a specific + * order. First come any events that the request generated, then any + * replies for the request, then the error response if there is one. After + * that, the server may spontaneously send more events with the same + * sequence number, which are not related to that request. + * + * This function will always return events from the pre-reply phase of the + * specified request. It may also return events from the unrelated + * post-reply stream, as long as they have the same sequence number. + * + * This function is useful for callers that need to process responses in + * wire-order. + * + * Implementation note: You cannot currently use this function to ensure + * that you process responses in exactly wire-order, because depending on + * the sequence of calls you make and the timing of server responses, + * post-reply events with the same sequence number may be returned as part + * of the pre-reply event stream, even though they were separated by a + * reply or error. In practice this kind of error is unlikely to matter, + * but it may be fixed in the future. + */ +xcb_generic_event_t *xcb_wait_for_event_until(xcb_connection_t *c, unsigned int request); + /** * @brief Return the error for a request, or NULL if none can ever arrive. * @param c: The connection to the X server. diff --git a/src/xcb_in.c b/src/xcb_in.c index 1199e23..ca75169 100644 --- a/src/xcb_in.c +++ b/src/xcb_in.c @@ -57,6 +57,7 @@ #endif struct event_list { + uint64_t sequence; xcb_generic_event_t *event; struct event_list *next; }; @@ -125,7 +126,7 @@ static int read_packet(xcb_connection_t *c) c->in.current_reply = 0; c->in.current_reply_tail = &c->in.current_reply; } - c->in.request_completed = c->in.request_read - 1; + c->in.request_completed = c->in.event_responses_completed = c->in.request_read - 1; } while(c->in.pending_replies && @@ -140,9 +141,12 @@ static int read_packet(xcb_connection_t *c) } if(genrep.response_type == XCB_ERROR) - c->in.request_completed = c->in.request_read; + c->in.request_completed = c->in.event_responses_completed = c->in.request_read; + else if(genrep.response_type == XCB_REPLY) + c->in.event_responses_completed = c->in.request_read; remove_finished_readers(&c->in.readers, c->in.request_completed); + remove_finished_readers(&c->in.event_readers, c->in.event_responses_completed); } if(genrep.response_type == XCB_ERROR || genrep.response_type == XCB_REPLY) @@ -231,11 +235,15 @@ static int read_packet(xcb_connection_t *c) free(buf); return 0; } + event->sequence = c->in.request_read; event->event = buf; event->next = 0; *c->in.events_tail = event; c->in.events_tail = &event->next; - pthread_cond_signal(&c->in.event_cond); + if(c->in.event_readers) + pthread_cond_signal(c->in.event_readers->data); + else + pthread_cond_signal(&c->in.event_cond); return 1; /* I have something for you... */ } @@ -542,6 +550,35 @@ xcb_generic_event_t *xcb_poll_for_event(xcb_connection_t *c) return ret; } +static xcb_generic_event_t *get_event_until(xcb_connection_t *c, uint64_t request) +{ + if(c->in.events && XCB_SEQUENCE_COMPARE(c->in.events->sequence, <=, request)) + return get_event(c); + return 0; +} + +xcb_generic_event_t *xcb_wait_for_event_until(xcb_connection_t *c, unsigned int request) +{ + pthread_cond_t cond = PTHREAD_COND_INITIALIZER; + reader_list reader; + xcb_generic_event_t *ret; + if(c->has_error) + return 0; + pthread_mutex_lock(&c->iolock); + + insert_reader(&c->in.event_readers, &reader, widen(c, request), &cond); + + while(!(ret = get_event_until(c, reader.request)) && XCB_SEQUENCE_COMPARE(c->in.event_responses_completed, <, reader.request)) + if(!_xcb_conn_wait(c, &cond, 0, 0)) + break; + + remove_reader(&c->in.event_readers, &reader); + pthread_cond_destroy(&cond); + _xcb_in_wake_up_next_reader(c); + pthread_mutex_unlock(&c->iolock); + return ret; +} + xcb_generic_error_t *xcb_request_check(xcb_connection_t *c, xcb_void_cookie_t cookie) { uint64_t request; @@ -612,6 +649,8 @@ void _xcb_in_wake_up_next_reader(xcb_connection_t *c) int pthreadret; if(c->in.readers) pthreadret = pthread_cond_signal(c->in.readers->data); + else if(c->in.event_readers) + pthreadret = pthread_cond_signal(c->in.event_readers->data); else pthreadret = pthread_cond_signal(&c->in.event_cond); assert(pthreadret == 0); diff --git a/src/xcbint.h b/src/xcbint.h index 096576c..95f078a 100644 --- a/src/xcbint.h +++ b/src/xcbint.h @@ -121,6 +121,7 @@ typedef struct _xcb_in { uint64_t request_expected; uint64_t request_read; + uint64_t event_responses_completed; uint64_t request_completed; struct reply_list *current_reply; struct reply_list **current_reply_tail; @@ -129,6 +130,7 @@ typedef struct _xcb_in { struct event_list *events; struct event_list **events_tail; struct reader_list *readers; + struct reader_list *event_readers; struct pending_reply *pending_replies; struct pending_reply **pending_replies_tail; -- 2.34.1