Simplify expression guard logic

Change-Id: I7d191bc8786452c5a1f14d024ff62d223adebd8b
Reviewed-by: Martin Jones <martin.jones@nokia.com>
Reviewed-by: Aaron Kennedy <aaron.kennedy@nokia.com>

3 files changed, 44 insertions, 38 deletions

diff --git a/src/declarative/qml/qdeclarativeexpression.cpp b/src/declarative/qml/qdeclarativeexpression.cpp
index 27979afb9c..d3ba92ab42 100644
--- a/src/declarative/qml/qdeclarativeexpression.cpp
+++ b/src/declarative/qml/qdeclarativeexpression.cpp
@@ -515,45 +515,18 @@ QDeclarativeJavaScriptExpression::GuardList::updateGuards(QDeclarativeJavaScript
 
         if (property.notifier != 0) {
 
-            if (!noChanges && guard.isConnected(property.notifier)) {
-                // Nothing to do
-
+            if (guard.isConnected(property.notifier)) {
+                 guard.cancelNotify();
             } else {
-                noChanges = false;
-
-                bool existing = false;
-                for (int jj = 0; !existing && jj < ii; ++jj) 
-                    if (endpoints[jj].isConnected(property.notifier)) 
-                        existing = true;
-
-                if (existing) {
-                    // duplicate
-                    guard.disconnect();
-                } else {
-                    guard.connect(property.notifier);
-                }
+                guard.connect(property.notifier);
             }
 
-
         } else if (property.notifyIndex != -1) {
 
-            if (!noChanges && guard.isConnected(property.object, property.notifyIndex)) {
-                // Nothing to do
-
-            } else {
-                noChanges = false;
-
-                bool existing = false;
-                for (int jj = 0; !existing && jj < ii; ++jj) 
-                    if (endpoints[jj].isConnected(property.object, property.notifyIndex)) 
-                        existing = true;
-
-                if (existing) {
-                    // duplicate
-                    guard.disconnect();
-                } else {
-                    guard.connect(property.object, property.notifyIndex);
-                }
+            if (guard.isConnected(property.object, property.notifyIndex)) {
+                guard.cancelNotify();
+            } else { 
+                guard.connect(property.object, property.notifyIndex);
             }
 
         } else {
diff --git a/src/declarative/qml/qdeclarativenotifier.cpp b/src/declarative/qml/qdeclarativenotifier.cpp
index a195280316..842cbf00b5 100644
--- a/src/declarative/qml/qdeclarativenotifier.cpp
+++ b/src/declarative/qml/qdeclarativenotifier.cpp
@@ -48,14 +48,15 @@ void QDeclarativeNotifier::emitNotify(QDeclarativeNotifierEndpoint *endpoint)
 {
     QDeclarativeNotifierEndpoint **oldDisconnected = endpoint->disconnected;
     endpoint->disconnected = &endpoint;
+    endpoint->notifying = 1;
 
     if (endpoint->next)
         emitNotify(endpoint->next);
 
     if (endpoint) {
-        void *args[] = { 0 };
 
         Q_ASSERT(endpoint->callback);
+        
         endpoint->callback(endpoint);
 
         if (endpoint) 
@@ -63,6 +64,7 @@ void QDeclarativeNotifier::emitNotify(QDeclarativeNotifierEndpoint *endpoint)
     } 
 
     if (oldDisconnected) *oldDisconnected = endpoint;
+    else if (endpoint) endpoint->notifying = 0;
 }
 
 void QDeclarativeNotifierEndpoint::connect(QObject *source, int sourceSignal)
@@ -91,6 +93,7 @@ void QDeclarativeNotifierEndpoint::copyAndClear(QDeclarativeNotifierEndpoint &ot
     other.notifier = notifier;
     other.sourceSignal = sourceSignal;
     other.disconnected = disconnected;
+    other.notifying = notifying;
     if (other.disconnected) *other.disconnected = &other;
 
     if (next) {
@@ -104,6 +107,7 @@ void QDeclarativeNotifierEndpoint::copyAndClear(QDeclarativeNotifierEndpoint &ot
     next = 0;
     disconnected = 0;
     notifier = 0;
+    notifying = 0;
     sourceSignal = -1;
 }
 
diff --git a/src/declarative/qml/qdeclarativenotifier_p.h b/src/declarative/qml/qdeclarativenotifier_p.h
index 1d0d4fc6f5..06c0ba0918 100644
--- a/src/declarative/qml/qdeclarativenotifier_p.h
+++ b/src/declarative/qml/qdeclarativenotifier_p.h
@@ -80,6 +80,9 @@ public:
     inline void connect(QDeclarativeNotifier *);
     inline void disconnect();
 
+    inline bool isNotifying() const;
+    inline void cancelNotify();
+
     void copyAndClear(QDeclarativeNotifierEndpoint &other);
 
 private:
@@ -90,7 +93,8 @@ private:
         QDeclarativeNotifier *notifier;
         QObject *source;
     };
-    int sourceSignal;
+    unsigned int notifying : 1;
+    signed int sourceSignal : 31;
     QDeclarativeNotifierEndpoint **disconnected;
     QDeclarativeNotifierEndpoint  *next;
     QDeclarativeNotifierEndpoint **prev;
@@ -124,7 +128,7 @@ void QDeclarativeNotifier::notify()
 }
 
 QDeclarativeNotifierEndpoint::QDeclarativeNotifierEndpoint()
-: callback(0), notifier(0), sourceSignal(-1), disconnected(0), next(0), prev(0)
+: callback(0), notifier(0), notifying(0), sourceSignal(-1), disconnected(0), next(0), prev(0)
 {
 }
 
@@ -140,7 +144,7 @@ bool QDeclarativeNotifierEndpoint::isConnected()
 
 bool QDeclarativeNotifierEndpoint::isConnected(QObject *source, int sourceSignal)
 {
-    return sourceSignal != -1 && this->source == source && this->sourceSignal == sourceSignal;
+    return this->sourceSignal != -1 && this->source == source && this->sourceSignal == sourceSignal;
 }
 
 bool QDeclarativeNotifierEndpoint::isConnected(QDeclarativeNotifier *notifier)
@@ -168,9 +172,34 @@ void QDeclarativeNotifierEndpoint::disconnect()
     prev = 0;
     disconnected = 0;
     notifier = 0;
+    notifying = 0;
     sourceSignal = -1;
 }
 
+/*!
+Returns true if a notify is in progress.  This means that the signal or QDeclarativeNotifier
+that this endpoing is connected to has been triggered, but this endpoint's callback has not
+yet been called.
+
+An in progress notify can be cancelled by calling cancelNotify.
+*/
+bool QDeclarativeNotifierEndpoint::isNotifying() const
+{
+    return notifying == 1;
+}
+
+/*!
+Cancel any notifies that are in progress.
+*/
+void QDeclarativeNotifierEndpoint::cancelNotify() 
+{
+    notifying = 0;
+    if (disconnected) {
+        *disconnected = 0;
+        disconnected = 0;
+    }
+}
+
 QT_END_NAMESPACE
 
 #endif // QDECLARATIVENOTIFIER_P_H