fix for incorrect handling of synchronous flag

include/amqpcpp/channelimpl.h

@@ -645,8 +645,17 @@ public:
         // skip if there is no oldest callback
         if (!_oldestCallback) return true;
         
-        // the last (possibly synchronous) operation was received, so we're no longer in synchronous mode
+        // remember whether or not we were synchronous
-        if (_synchronous && _queue.empty()) _synchronous = false;
+        bool synchronous = _synchronous;
+
+        // is the queue empty at this moment?
+        bool empty = _queue.empty();
+        
+        // the last (possibly synchronous) operation was received, so we're no longer in synchronous mode. this
+        // is an optimization that makes sure that the first instruction _after_ a synchronous instruction
+        // that is installed during the success callback we make later does _not_ need to be buffered, but can be
+        // sent directly
+        if (synchronous && empty) _synchronous = false;
 
         // we are going to call callbacks that could destruct the channel
         Monitor monitor(this);
@@ -661,6 +670,10 @@ public:
         // leap out if channel no longer exists
         if (!monitor.valid()) return false;
 
+        // if we were synchronous, but there were still messages in the queue, we process the queue now, because the synchronous
+        // operation was finished, and its callback was made, which means we're no longer in synchronous mode
+        if (synchronous && !empty) onSynchronized();
+
         // set the oldest callback
         _oldestCallback = next;
 

src/basiccancelokframe.h

@@ -94,7 +94,7 @@ public:
         if (!channel) return false;
 
         // report
-        if (channel->reportSuccess<const std::string&>(consumerTag())) channel->onSynchronized();
+        channel->reportSuccess<const std::string&>(consumerTag());
 
         // done
         return true;

src/basicconsumeokframe.h

@@ -94,7 +94,7 @@ public:
         if (!channel) return false;
 
         // report
-        if (channel->reportSuccess(consumerTag())) channel->onSynchronized();
+        channel->reportSuccess(consumerTag());
 
         // done
         return true;

src/basicgetemptyframe.h

@@ -84,7 +84,7 @@ public:
         if (!channel) return false;
 
         // report
-        if (channel->reportSuccess()) channel->onSynchronized();
+        channel->reportSuccess();
 
         // done
         return true;

src/basicqosokframe.h

@@ -67,7 +67,7 @@ public:
         if (!channel) return false;
 
         // report
-        if (channel->reportSuccess()) channel->onSynchronized();
+        channel->reportSuccess();
 
         // done
         return true;

src/channelcloseokframe.h

@@ -72,7 +72,7 @@ public:
         if (!channel) return false;
 
         // report that the channel is closed
-        if (channel->reportClosed()) channel->onSynchronized();
+        channel->reportClosed();
 
         // done
         return true;

src/channelflowokframe.h

@@ -93,7 +93,7 @@ public:
         if (!channel) return false;
 
         // report success for the call
-        if (channel->reportSuccess()) channel->onSynchronized();
+        channel->reportSuccess();
 
         // done
         return true;

src/confirmselectokframe.h

@@ -75,7 +75,7 @@ public:
         if(!channel) return false;
 
         // report that the channel is open
-        if (channel->reportSuccess()) channel->onSynchronized();
+        channel->reportSuccess();
 
         // done
         return true;

src/exchangebindokframe.h

@@ -67,7 +67,7 @@ public:
         if(!channel) return false;
 
         // report to handler
-        if (channel->reportSuccess()) channel->onSynchronized();
+        channel->reportSuccess();
 
         // done
         return true;

src/exchangedeclareokframe.h

@@ -70,7 +70,7 @@ public:
         if(!channel) return false;
 
         // report exchange declare ok
-        if (channel->reportSuccess()) channel->onSynchronized();
+        channel->reportSuccess();
 
         // done
         return true;

src/exchangedeleteokframe.h

@@ -71,7 +71,7 @@ public:
         if(!channel) return false;
 
         // report to handler
-        if (channel->reportSuccess()) channel->onSynchronized();
+        channel->reportSuccess();
 
         // done
         return true;

src/exchangeunbindokframe.h

@@ -68,7 +68,7 @@ public:
         if(!channel) return false;
 
         // report to handler
-        if (channel->reportSuccess()) channel->onSynchronized();
+        channel->reportSuccess();
 
         // done
         return true;

src/queuebindokframe.h

@@ -69,7 +69,7 @@ public:
         if(!channel) return false;
 
         // report to handler
-        if (channel->reportSuccess()) channel->onSynchronized();
+        channel->reportSuccess();
 
         // done
         return true;

src/queuedeclareokframe.h

@@ -133,7 +133,7 @@ public:
         if (!channel) return false;
 
         // report success
-        if (channel->reportSuccess(name(), messageCount(), consumerCount())) channel->onSynchronized();
+        channel->reportSuccess(name(), messageCount(), consumerCount());
 
         // done
         return true;

src/queuedeleteokframe.h

@@ -94,7 +94,7 @@ public:
         if(!channel) return false;
 
         // report queue deletion success
-        if (channel->reportSuccess(this->messageCount())) channel->onSynchronized();
+        channel->reportSuccess(this->messageCount());
 
         // done
         return true;

src/queuepurgeokframe.h

@@ -94,7 +94,7 @@ public:
         if(!channel) return false;
 
         // report queue purge success
-        if (channel->reportSuccess(this->messageCount())) channel->onSynchronized();
+        channel->reportSuccess(this->messageCount());
 
         // done
         return true;

src/queueunbindokframe.h

@@ -73,7 +73,7 @@ public:
         if(!channel) return false;
 
         // report queue unbind success
-        if (channel->reportSuccess()) channel->onSynchronized();
+        channel->reportSuccess();
 
         // done
         return true;

src/transactioncommitokframe.h

@@ -74,7 +74,7 @@ public:
         if(!channel) return false;
 
         // report that the channel is open
-        if (channel->reportSuccess()) channel->onSynchronized();
+        channel->reportSuccess();
 
         // done
         return true;

src/transactionrollbackokframe.h

@@ -74,7 +74,7 @@ public:
         if(!channel) return false;
 
         // report that the channel is open
-        if (channel->reportSuccess()) channel->onSynchronized();
+        channel->reportSuccess();
 
         // done
         return true;

src/transactionselectokframe.h

@@ -74,7 +74,7 @@ public:
         if(!channel) return false;
 
         // report that the channel is open
-        if (channel->reportSuccess()) channel->onSynchronized();
+        channel->reportSuccess();
 
         // done
         return true;