Encapsulate QQmlContextData

This class is not a private detail of QQmlContext. And it is incredibly
hard to see who owns what in there. Let's add some civilization ...

We enforce refcounting for QQmlContextData across the code base, with
two exceptions:

1. QQmlContextPrivate may or may not own its QQmlContextData.
2. We may request a QQmlContextData owned by its parent QQmlContextData.

For these two cases we keep flags in QQmlContextData and when the
respective field (m_parent or m_publicContext) is reset, we release()
once.

Furthermore, QQmlContextData and QQmlGuardedContextData are moved to
their own files, in order to de-spaghettify qqmlcontext_p.h and
qqmlcontext.cpp.

When the QQmlEngine is deleted, any QQmlComponents drop their object
creators now, in order to release any context data held by those.
Before, the context data would be deleted, but the object creators would
retain the dangling pointer.

[ChangeLog][QML][Important Behavior Changes] QQmlContext::baseUrl() does
what the documentation says now: It prefers explicitly set baseUrls over
compilation unit URLs. Only if no baseUrl is set, the CU's URL is
returned. It used to prefer the CU's URL.

Change-Id: Ieeb5dcb07b45d891526191321386d5443b8f5738
Reviewed-by: Fabian Kosmale <fabian.kosmale@qt.io>

5 files changed, 22 insertions, 24 deletions

diff --git a/src/plugins/qmltooling/qmldbg_debugger/qqmlenginedebugservice.cpp b/src/plugins/qmltooling/qmldbg_debugger/qqmlenginedebugservice.cpp
index d435e82390..1aa24ea3a4 100644
--- a/src/plugins/qmltooling/qmldbg_debugger/qqmlenginedebugservice.cpp
+++ b/src/plugins/qmltooling/qmldbg_debugger/qqmlenginedebugservice.cpp
@@ -389,7 +389,7 @@ void QQmlEngineDebugServiceImpl::buildObjectList(QDataStream &message,
     if (!ctxt->isValid())
         return;
 
-    QQmlContextData *p = QQmlContextData::get(ctxt);
+    QQmlRefPointer<QQmlContextData> p = QQmlContextData::get(ctxt);
 
     QString ctxtName = ctxt->objectName();
     int ctxtId = QQmlDebugService::idForObject(ctxt);
@@ -400,31 +400,31 @@ void QQmlEngineDebugServiceImpl::buildObjectList(QDataStream &message,
 
     int count = 0;
 
-    QQmlContextData *child = p->childContexts;
+    QQmlRefPointer<QQmlContextData> child = p->childContexts();
     while (child) {
         ++count;
-        child = child->nextChild;
+        child = child->nextChild();
     }
 
     message << count;
 
-    child = p->childContexts;
+    child = p->childContexts();
     while (child) {
         buildObjectList(message, child->asQQmlContext(), instances);
-        child = child->nextChild;
+        child = child->nextChild();
     }
 
     count = 0;
     for (int ii = 0; ii < instances.count(); ++ii) {
         QQmlData *data = QQmlData::get(instances.at(ii));
-        if (data->context == p)
+        if (data->context == p.data())
             count ++;
     }
     message << count;
 
     for (int ii = 0; ii < instances.count(); ++ii) {
         QQmlData *data = QQmlData::get(instances.at(ii));
-        if (data->context == p)
+        if (data->context == p.data())
             message << objectData(instances.at(ii));
     }
 }
@@ -522,16 +522,11 @@ void QQmlEngineDebugServiceImpl::processMessage(const QByteArray &message)
 
         if (engine) {
             QQmlContext *rootContext = engine->rootContext();
-            // Clean deleted objects
             QQmlContextPrivate *ctxtPriv = QQmlContextPrivate::get(rootContext);
-            for (int ii = 0; ii < ctxtPriv->instances.count(); ++ii) {
-                if (!ctxtPriv->instances.at(ii)) {
-                    ctxtPriv->instances.removeAt(ii);
-                    --ii;
-                }
-            }
-            buildObjectList(rs, rootContext, ctxtPriv->instances);
-            buildStatesList(true, ctxtPriv->instances);
+            ctxtPriv->cleanInstances(); // Clean deleted objects
+            const QList<QPointer<QObject>> instances = ctxtPriv->instances();
+            buildObjectList(rs, rootContext, instances);
+            buildStatesList(true, instances);
         }
 
     } else if (type == "FETCH_OBJECT") {
@@ -783,7 +778,7 @@ bool QQmlEngineDebugServiceImpl::setMethodBody(int objectId, const QString &meth
     QQmlContext *context = qmlContext(object);
     if (!object || !context || !context->isValid())
         return false;
-    QQmlContextData *contextData = QQmlContextData::get(context);
+    QQmlRefPointer<QQmlContextData> contextData = QQmlContextData::get(context);
 
     QQmlPropertyData dummy;
     QQmlPropertyData *prop =
diff --git a/src/plugins/qmltooling/qmldbg_debugger/qv4debugjob.cpp b/src/plugins/qmltooling/qmldbg_debugger/qv4debugjob.cpp
index 333ce4b26f..a70941682b 100644
--- a/src/plugins/qmltooling/qmldbg_debugger/qv4debugjob.cpp
+++ b/src/plugins/qmltooling/qmldbg_debugger/qv4debugjob.cpp
@@ -88,10 +88,10 @@ void JavaScriptJob::run()
             QV4::ScopedObject withContext(scope, engine->newObject());
             QV4::ScopedString k(scope);
             QV4::ScopedValue v(scope);
-            for (int ii = 0; ii < ctxtPriv->instances.count(); ++ii) {
-                QObject *object = ctxtPriv->instances.at(ii);
-                if (QQmlContext *context = qmlContext(object)) {
-                    if (QQmlContextData *cdata = QQmlContextData::get(context)) {
+            const QList<QPointer<QObject>> instances = ctxtPriv->instances();
+            for (const QPointer<QObject> &object : instances) {
+                if (QQmlContext *context = qmlContext(object.data())) {
+                    if (QQmlRefPointer<QQmlContextData> cdata = QQmlContextData::get(context)) {
                         v = QV4::QObjectWrapper::wrap(engine, object);
                         k = engine->newString(cdata->findObjectId(object));
                         withContext->put(k, v);
diff --git a/src/plugins/qmltooling/qmldbg_inspector/globalinspector.cpp b/src/plugins/qmltooling/qmldbg_inspector/globalinspector.cpp
index 012730902b..301db59952 100644
--- a/src/plugins/qmltooling/qmldbg_inspector/globalinspector.cpp
+++ b/src/plugins/qmltooling/qmldbg_inspector/globalinspector.cpp
@@ -298,7 +298,7 @@ QString GlobalInspector::idStringForObject(QObject *obj) const
 {
     QQmlContext *context = qmlContext(obj);
     if (context) {
-        QQmlContextData *cdata = QQmlContextData::get(context);
+        QQmlRefPointer<QQmlContextData> cdata = QQmlContextData::get(context);
         if (cdata)
             return cdata->findObjectId(obj);
     }
diff --git a/src/plugins/qmltooling/qmldbg_preview/qqmldebugtranslationservice.cpp b/src/plugins/qmltooling/qmldbg_preview/qqmldebugtranslationservice.cpp
index 1561777202..5da26e9610 100644
--- a/src/plugins/qmltooling/qmldbg_preview/qqmldebugtranslationservice.cpp
+++ b/src/plugins/qmltooling/qmldbg_preview/qqmldebugtranslationservice.cpp
@@ -58,7 +58,9 @@ QString QQmlDebugTranslationServiceImpl::foundElidedText(QObject *textObject, co
     return elideText;
 }
 
-void QQmlDebugTranslationServiceImpl::foundTranslationBinding(QQmlTranslationBinding *binding, QObject *scopeObject, QQmlContextData *contextData)
+void QQmlDebugTranslationServiceImpl::foundTranslationBinding(
+        QQmlTranslationBinding *binding, QObject *scopeObject,
+        const QQmlRefPointer<QQmlContextData> &contextData)
 {
     Q_UNUSED(binding)
     Q_UNUSED(scopeObject)
diff --git a/src/plugins/qmltooling/qmldbg_preview/qqmldebugtranslationservice.h b/src/plugins/qmltooling/qmldbg_preview/qqmldebugtranslationservice.h
index a337a937a5..802f21ecce 100644
--- a/src/plugins/qmltooling/qmldbg_preview/qqmldebugtranslationservice.h
+++ b/src/plugins/qmltooling/qmldbg_preview/qqmldebugtranslationservice.h
@@ -78,7 +78,8 @@ public:
     QQmlDebugTranslationServiceImpl(QObject *parent = 0);
 
     QString foundElidedText(QObject *textObject, const QString &layoutText, const QString &elideText) override;
-    void foundTranslationBinding(QQmlTranslationBinding *binding, QObject *scopeObject, QQmlContextData *contextData) override;
+    void foundTranslationBinding(QQmlTranslationBinding *binding, QObject *scopeObject,
+                                 const QQmlRefPointer<QQmlContextData> &contextData) override;
     void messageReceived(const QByteArray &message) override;
 };