From c7d8462bf8919fa887d264adcccdf1e38eb6422c Mon Sep 17 00:00:00 2001
From: Christian Kamm <christian.d.kamm@nokia.com>
Date: Mon, 26 Sep 2011 15:07:12 +0200
Subject: [PATCH] QmlJS: Fix threading issue in QmlObjectValue.

Still need to get rid of the lock in ValueOwner::registerValue.

Change-Id: If9bbc548de54edf52805906aaaf730f5c66573dd
Reviewed-on: http://codereview.qt-project.org/5542
Reviewed-by: Fawzi Mohamed <fawzi.mohamed@nokia.com>
---
 src/libs/qmljs/qmljsinterpreter.cpp | 26 ++++++++++++++------------
 src/libs/qmljs/qmljsinterpreter.h   |  4 +---
 src/libs/qmljs/qmljsvalueowner.cpp  |  1 +
 3 files changed, 16 insertions(+), 15 deletions(-)

diff --git a/src/libs/qmljs/qmljsinterpreter.cpp b/src/libs/qmljs/qmljsinterpreter.cpp
index 94518dbde99..3c57475f67d 100644
--- a/src/libs/qmljs/qmljsinterpreter.cpp
+++ b/src/libs/qmljs/qmljsinterpreter.cpp
@@ -182,17 +182,6 @@ QmlObjectValue::QmlObjectValue(FakeMetaObject::ConstPtr metaObject, const QStrin
 QmlObjectValue::~QmlObjectValue()
 {}
 
-const Value *QmlObjectValue::findOrCreateSignature(int index, const FakeMetaMethod &method, QString *methodName) const
-{
-    *methodName = method.methodName();
-    const Value *value = _metaSignature.value(index);
-    if (! value) {
-        value = new MetaFunction(method, valueOwner());
-        _metaSignature.insert(index, value);
-    }
-    return value;
-}
-
 void QmlObjectValue::processMembers(MemberProcessor *processor) const
 {
     // process the meta enums
@@ -207,6 +196,19 @@ void QmlObjectValue::processMembers(MemberProcessor *processor) const
     // all explicitly defined signal names
     QSet<QString> explicitSignals;
 
+    // make MetaFunction instances lazily when first needed
+    QList<const Value *> *signatures = _metaSignatures;
+    if (!signatures) {
+        signatures = new QList<const Value *>;
+        signatures->reserve(_metaObject->methodCount());
+        for (int index = 0; index < _metaObject->methodCount(); ++index)
+            signatures->append(new MetaFunction(_metaObject->method(index), valueOwner()));
+        if (!_metaSignatures.testAndSetOrdered(0, signatures)) {
+            delete signatures;
+            signatures = _metaSignatures;
+        }
+    }
+
     // process the meta methods
     for (int index = 0; index < _metaObject->methodCount(); ++index) {
         const FakeMetaMethod method = _metaObject->method(index);
@@ -214,7 +216,7 @@ void QmlObjectValue::processMembers(MemberProcessor *processor) const
             continue;
 
         QString methodName;
-        const Value *signature = findOrCreateSignature(index, method, &methodName);
+        const Value *signature = signatures->at(index);
 
         if (method.methodType() == FakeMetaMethod::Slot && method.access() == FakeMetaMethod::Public) {
             processor->processSlot(methodName, signature);
diff --git a/src/libs/qmljs/qmljsinterpreter.h b/src/libs/qmljs/qmljsinterpreter.h
index 804e52b03e3..92d1978e9fe 100644
--- a/src/libs/qmljs/qmljsinterpreter.h
+++ b/src/libs/qmljs/qmljsinterpreter.h
@@ -449,8 +449,6 @@ public:
     LanguageUtils::FakeMetaEnum getEnum(const QString &typeName, const QmlObjectValue **foundInScope = 0) const;
     const QmlEnumValue *getEnumValue(const QString &typeName, const QmlObjectValue **foundInScope = 0) const;
 protected:
-    const Value *findOrCreateSignature(int index, const LanguageUtils::FakeMetaMethod &method,
-                                       QString *methodName) const;
     bool isDerivedFrom(LanguageUtils::FakeMetaObject::ConstPtr base) const;
 
 private:
@@ -462,7 +460,7 @@ private:
     // needed in cases when B 1.0 has A 1.1 as prototype when imported as 1.1
     const LanguageUtils::ComponentVersion _componentVersion;
     const LanguageUtils::ComponentVersion _importVersion;
-    mutable QHash<int, const Value *> _metaSignature;
+    mutable QAtomicPointer< QList<const Value *> > _metaSignatures;
     QHash<QString, const QmlEnumValue * > _enums;
     int _metaObjectRevision;
 };
diff --git a/src/libs/qmljs/qmljsvalueowner.cpp b/src/libs/qmljs/qmljsvalueowner.cpp
index c6ef8fd52c2..aaa9f4d28b4 100644
--- a/src/libs/qmljs/qmljsvalueowner.cpp
+++ b/src/libs/qmljs/qmljsvalueowner.cpp
@@ -453,6 +453,7 @@ const ObjectValue *ValueOwner::qtObject() const
 
 void ValueOwner::registerValue(Value *value)
 {
+    // ### get rid of this lock
     QMutexLocker locker(&_mutex);
     _registeredValues.append(value);
 }