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-rw-r--r--libxcb/src/xcb_out.c57
-rw-r--r--libxcb/src/xcb_util.c17
2 files changed, 49 insertions, 25 deletions
diff --git a/libxcb/src/xcb_out.c b/libxcb/src/xcb_out.c
index 18bb5f912..dc4295467 100644
--- a/libxcb/src/xcb_out.c
+++ b/libxcb/src/xcb_out.c
@@ -103,6 +103,33 @@ static void get_socket_back(xcb_connection_t *c)
_xcb_in_replies_done(c);
}
+static void prepare_socket_request(xcb_connection_t *c)
+{
+ /* We're about to append data to out.queue, so we need to
+ * atomically test for an external socket owner *and* some other
+ * thread currently writing.
+ *
+ * If we have an external socket owner, we have to get the socket back
+ * before we can use it again.
+ *
+ * If some other thread is writing to the socket, we assume it's
+ * writing from out.queue, and so we can't stick data there.
+ *
+ * We satisfy this condition by first calling get_socket_back
+ * (which may drop the lock, but will return when XCB owns the
+ * socket again) and then checking for another writing thread and
+ * escaping the loop if we're ready to go.
+ */
+ for (;;) {
+ if(c->has_error)
+ return;
+ get_socket_back(c);
+ if (!c->out.writing)
+ break;
+ pthread_cond_wait(&c->out.cond, &c->iolock);
+ }
+}
+
/* Public interface */
void xcb_prefetch_maximum_request_length(xcb_connection_t *c)
@@ -236,24 +263,23 @@ unsigned int xcb_send_request(xcb_connection_t *c, int flags, struct iovec *vect
/* get a sequence number and arrange for delivery. */
pthread_mutex_lock(&c->iolock);
- /* wait for other writing threads to get out of my way. */
- while(c->out.writing)
- pthread_cond_wait(&c->out.cond, &c->iolock);
- get_socket_back(c);
+
+ prepare_socket_request(c);
/* send GetInputFocus (sync_req) when 64k-2 requests have been sent without
- * a reply. */
- if(req->isvoid && c->out.request == c->in.request_expected + (1 << 16) - 2)
- send_sync(c);
- /* Also send sync_req (could use NoOp) at 32-bit wrap to avoid having
+ * a reply.
+ * Also send sync_req (could use NoOp) at 32-bit wrap to avoid having
* applications see sequence 0 as that is used to indicate
- * an error in sending the request */
- if((unsigned int) (c->out.request + 1) == 0)
+ * an error in sending the request
+ */
+
+ while ((req->isvoid && c->out.request == c->in.request_expected + (1 << 16) - 2) ||
+ (unsigned int) (c->out.request + 1) == 0)
+ {
send_sync(c);
+ prepare_socket_request(c);
+ }
- /* The above send_sync calls could drop the I/O lock, but this
- * thread will still exclude any other thread that tries to write,
- * so the sequence number postconditions still hold. */
send_request(c, req->isvoid, workaround, flags, vector, veclen);
request = c->has_error ? 0 : c->out.request;
pthread_mutex_unlock(&c->iolock);
@@ -373,10 +399,7 @@ int _xcb_out_send(xcb_connection_t *c, struct iovec *vector, int count)
void _xcb_out_send_sync(xcb_connection_t *c)
{
- /* wait for other writing threads to get out of my way. */
- while(c->out.writing)
- pthread_cond_wait(&c->out.cond, &c->iolock);
- get_socket_back(c);
+ prepare_socket_request(c);
send_sync(c);
}
diff --git a/libxcb/src/xcb_util.c b/libxcb/src/xcb_util.c
index 1625742b1..f8d381d3b 100644
--- a/libxcb/src/xcb_util.c
+++ b/libxcb/src/xcb_util.c
@@ -438,16 +438,17 @@ xcb_connection_t *xcb_connect_to_display_with_auth_info(const char *displayname,
if(!parsed) {
c = _xcb_conn_ret_error(XCB_CONN_CLOSED_PARSE_ERR);
goto out;
- } else {
+ }
+
#ifdef _WIN32
- WSADATA wsaData;
- if (WSAStartup(MAKEWORD(2, 2), &wsaData) != 0) {
- c = _xcb_conn_ret_error(XCB_CONN_ERROR);
- goto out;
- }
-#endif
- fd = _xcb_open(host, protocol, display);
+ WSADATA wsaData;
+ if (WSAStartup(MAKEWORD(2, 2), &wsaData) != 0) {
+ c = _xcb_conn_ret_error(XCB_CONN_ERROR);
+ goto out;
}
+#endif
+
+ fd = _xcb_open(host, protocol, display);
if(fd == -1) {
c = _xcb_conn_ret_error(XCB_CONN_ERROR);