API/ABI break: Add flags to XCBSendRequest, first for error-checked requests.

There's no more race condition between event and reply handling.
The *RequestBlind and *RequestChecked functions are not yet implemented.

src/c-client.xsl

@@ -611,7 +611,11 @@ authorization from the authors.
       </xsl:if>;</l>
     </xsl:for-each>
 
-    <l>XCBSendRequest(c, &amp;xcb_ret.sequence, xcb_parts, &amp;xcb_req);</l>
+    <l>XCBSendRequest(c, &amp;xcb_ret.sequence, <!--
+    --><xsl:choose>
+         <xsl:when test="@has-reply">XCB_REQUEST_CHECKED</xsl:when>
+         <xsl:otherwise>0</xsl:otherwise>
+       </xsl:choose>, xcb_parts, &amp;xcb_req);</l>
     <l>return xcb_ret;</l>
   </xsl:template>
 

src/xcb_in.c

@@ -39,21 +39,15 @@
 typedef struct pending_reply {
     unsigned int request;
     enum workarounds workaround;
+    int flags;
     struct pending_reply *next;
 } pending_reply;
 
 typedef struct XCBReplyData {
     unsigned int request;
     void *data;
-    XCBGenericError **error;
 } XCBReplyData;
 
-static int match_request_error(const void *request, const void *data)
-{
-    const XCBGenericError *e = data;
-    return e->response_type == 0 && e->sequence == ((*(unsigned int *) request) & 0xffff);
-}
-
 static int match_reply(const void *request, const void *data)
 {
     return ((XCBReplyData *) data)->request == *(unsigned int *) request;
@@ -75,6 +69,7 @@ static int read_packet(XCBConnection *c)
     XCBGenericRep genrep;
     int length = 32;
     unsigned char *buf;
+    pending_reply *pend = 0;
 
     /* Wait for there to be enough data for us to read a whole packet */
     if(c->in.queue_len < length)
@@ -88,36 +83,40 @@ static int read_packet(XCBConnection *c)
     {
         int lastread = c->in.request_read;
         c->in.request_read = (lastread & 0xffff0000) | genrep.sequence;
-        if(c->in.request_read != lastread && !_xcb_queue_is_empty(c->in.current_reply))
+        if(c->in.request_read != lastread)
         {
-            _xcb_map_put(c->in.replies, lastread, c->in.current_reply);
+            pending_reply *oldpend = c->in.pending_replies;
-            c->in.current_reply = _xcb_queue_new();
+            if(oldpend && oldpend->request == lastread)
+            {
+                c->in.pending_replies = oldpend->next;
+                if(!oldpend->next)
+                    c->in.pending_replies_tail = &c->in.pending_replies;
+                free(oldpend);
+            }
+            if(!_xcb_queue_is_empty(c->in.current_reply))
+            {
+                _xcb_map_put(c->in.replies, lastread, c->in.current_reply);
+                c->in.current_reply = _xcb_queue_new();
+            }
         }
         if(c->in.request_read < lastread)
             c->in.request_read += 0x10000;
     }
 
+    if(genrep.response_type == 0 || genrep.response_type == 1)
+    {
+        pend = c->in.pending_replies;
+        if(pend && pend->request != c->in.request_read)
+            pend = 0;
+    }
+
     /* For reply packets, check that the entire packet is available. */
     if(genrep.response_type == 1)
     {
-        pending_reply *pend = c->in.pending_replies;
+        if(pend && pend->workaround == WORKAROUND_GLX_GET_FB_CONFIGS_BUG)
-        if(pend && pend->request == c->in.request_read)
         {
-            switch(pend->workaround)
+            CARD32 *p = (CARD32 *) c->in.queue;
-            {
+            genrep.length = p[2] * p[3] * 2;
-            case WORKAROUND_NONE:
-                break;
-            case WORKAROUND_GLX_GET_FB_CONFIGS_BUG:
-                {
-                    CARD32 *p = (CARD32 *) c->in.queue;
-                    genrep.length = p[2] * p[3] * 2;
-                }
-                break;
-            }
-            c->in.pending_replies = pend->next;
-            if(!pend->next)
-                c->in.pending_replies_tail = &c->in.pending_replies;
-            free(pend);
         }
         length += genrep.length * 4;
     }
@@ -131,7 +130,8 @@ static int read_packet(XCBConnection *c)
         return 0;
     }
 
-    if(buf[0] == 1) /* response is a reply */
+    /* reply, or checked error */
+    if(genrep.response_type == 1 || (genrep.response_type == 0 && pend && (pend->flags & XCB_REQUEST_CHECKED)))
     {
         XCBReplyData *reader = _xcb_list_find(c->in.readers, match_reply, &c->in.request_read);
         _xcb_queue_enqueue(c->in.current_reply, buf);
@@ -140,18 +140,7 @@ static int read_packet(XCBConnection *c)
         return 1;
     }
 
-    if(buf[0] == 0) /* response is an error */
+    /* event, or unchecked error */
-    {
-        XCBReplyData *reader = _xcb_list_find(c->in.readers, match_reply, &c->in.request_read);
-        if(reader && reader->error)
-        {
-            *reader->error = (XCBGenericError *) buf;
-            pthread_cond_signal(reader->data);
-            return 1;
-        }
-    }
-
-    /* event, or error without a waiting reader */
     _xcb_queue_enqueue(c->in.events, buf);
     pthread_cond_signal(&c->in.event_cond);
     return 1; /* I have something for you... */
@@ -198,20 +187,12 @@ void *XCBWaitForReply(XCBConnection *c, unsigned int request, XCBGenericError **
     if(_xcb_list_find(c->in.readers, match_reply, &request))
         goto done; /* error */
 
-    if(e)
-    {
-        *e = _xcb_list_remove(c->in.events, match_request_error, &request);
-        if(*e)
-            goto done;
-    }
-
     reader.request = request;
     reader.data = &cond;
-    reader.error = e;
     _xcb_list_append(c->in.readers, &reader);
 
     /* If this request has not been read yet, wait for it. */
-    while(!(e && *e) && ((signed int) (c->in.request_read - request) < 0 ||
+    while(((signed int) (c->in.request_read - request) < 0 ||
             (c->in.request_read == request &&
 	     _xcb_queue_is_empty(c->in.current_reply))))
         if(!_xcb_conn_wait(c, /*should_write*/ 0, &cond))
@@ -230,6 +211,15 @@ void *XCBWaitForReply(XCBConnection *c, unsigned int request, XCBGenericError **
     else
         ret = _xcb_queue_dequeue(c->in.current_reply);
 
+    if(ret && ((XCBGenericRep *) ret)->response_type == 0) /* X error */
+    {
+        if(e)
+            *e = ret;
+        else
+            free(ret);
+        ret = 0;
+    }
+
 done:
     _xcb_list_remove(c->in.readers, match_reply, &request);
     pthread_cond_destroy(&cond);
@@ -328,15 +318,16 @@ void _xcb_in_destroy(_xcb_in *in)
     }
 }
 
-int _xcb_in_expect_reply(XCBConnection *c, unsigned int request, enum workarounds workaround)
+int _xcb_in_expect_reply(XCBConnection *c, unsigned int request, enum workarounds workaround, int flags)
 {
-    if(workaround != WORKAROUND_NONE)
+    if(workaround != WORKAROUND_NONE || flags != 0)
     {
         pending_reply *pend = malloc(sizeof(pending_reply));
         if(!pend)
             return 0;
         pend->request = request;
         pend->workaround = workaround;
+        pend->flags = flags;
         pend->next = 0;
         *c->in.pending_replies_tail = pend;
         c->in.pending_replies_tail = &pend->next;

src/xcb_out.c

@@ -79,7 +79,7 @@ CARD32 XCBGetMaximumRequestLength(XCBConnection *c)
     return c->out.maximum_request_length;
 }
 
-int XCBSendRequest(XCBConnection *c, unsigned int *request, struct iovec *vector, const XCBProtocolRequest *req)
+int XCBSendRequest(XCBConnection *c, unsigned int *request, int flags, struct iovec *vector, const XCBProtocolRequest *req)
 {
     static const char pad[3];
     int ret;
@@ -105,7 +105,7 @@ int XCBSendRequest(XCBConnection *c, unsigned int *request, struct iovec *vector
         ((CARD8 *) vector[0].iov_base)[1] = req->opcode;
 
         /* do we need to work around the X server bug described in glx.xml? */
-        if(strcmp(req->ext->name, "GLX") &&
+        if(!req->isvoid && strcmp(req->ext->name, "GLX") &&
                 ((req->opcode == 17 && ((CARD32 *) vector[0].iov_base)[0] == 0x10004) ||
                  req->opcode == 21))
             workaround = WORKAROUND_GLX_GET_FB_CONFIGS_BUG;
@@ -172,8 +172,7 @@ int XCBSendRequest(XCBConnection *c, unsigned int *request, struct iovec *vector
 
     *request = ++c->out.request;
 
-    if(!req->isvoid)
+    _xcb_in_expect_reply(c, *request, workaround, flags);
-        _xcb_in_expect_reply(c, *request, workaround);
 
     ret = _xcb_out_write_block(c, padded, padlen);
     pthread_mutex_unlock(&c->iolock);

src/xcbext.h

@@ -51,7 +51,11 @@ typedef struct {
     BOOL isvoid;
 } XCBProtocolRequest;
 
-int XCBSendRequest(XCBConnection *c, unsigned int *sequence, struct iovec *vector, const XCBProtocolRequest *request);
+enum XCBSendRequestFlags {
+    XCB_REQUEST_CHECKED = 1 << 0
+};
+
+int XCBSendRequest(XCBConnection *c, unsigned int *sequence, int flags, struct iovec *vector, const XCBProtocolRequest *request);
 
 
 /* xcb_in.c */

src/xcbint.h

@@ -119,7 +119,7 @@ typedef struct _xcb_in {
 int _xcb_in_init(_xcb_in *in);
 void _xcb_in_destroy(_xcb_in *in);
 
-int _xcb_in_expect_reply(XCBConnection *c, unsigned int request, enum workarounds workaround);
+int _xcb_in_expect_reply(XCBConnection *c, unsigned int request, enum workarounds workaround, int flags);
 
 int _xcb_in_read(XCBConnection *c);
 int _xcb_in_read_block(XCBConnection *c, void *buf, int nread);