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>

1 files changed, 62 insertions, 52 deletions

diff --git a/src/qml/jsruntime/qv4qmlcontext.cpp b/src/qml/jsruntime/qv4qmlcontext.cpp
index 4538900d21..9863edead0 100644
--- a/src/qml/jsruntime/qv4qmlcontext.cpp
+++ b/src/qml/jsruntime/qv4qmlcontext.cpp
@@ -64,23 +64,25 @@ using namespace QV4;
 DEFINE_OBJECT_VTABLE(QQmlContextWrapper);
 DEFINE_MANAGED_VTABLE(QmlContext);
 
-void Heap::QQmlContextWrapper::init(QQmlContextData *context, QObject *scopeObject)
+void Heap::QQmlContextWrapper::init(QQmlRefPointer<QQmlContextData> context, QObject *scopeObject)
 {
     Object::init();
-    this->context = new QQmlContextDataRef(context);
+    this->context = context.take();
     this->scopeObject.init(scopeObject);
 }
 
 void Heap::QQmlContextWrapper::destroy()
 {
-    delete context;
+    context->release();
+    context = nullptr;
     scopeObject.destroy();
     Object::destroy();
 }
 
-static OptionalReturnedValue searchContextProperties(QV4::ExecutionEngine *v4, QQmlContextData *context, String *name,
-                                                     bool *hasProperty, Value *base, QV4::Lookup *lookup,
-                                                     QV4::Lookup *originalLookup, QQmlEnginePrivate *ep)
+static OptionalReturnedValue searchContextProperties(
+        QV4::ExecutionEngine *v4, const QQmlRefPointer<QQmlContextData> &context, String *name,
+        bool *hasProperty, Value *base, QV4::Lookup *lookup, QV4::Lookup *originalLookup,
+        QQmlEnginePrivate *ep)
 {
     const QV4::IdentifierHash &properties = context->propertyNames();
     if (properties.count() == 0)
@@ -91,7 +93,7 @@ static OptionalReturnedValue searchContextProperties(QV4::ExecutionEngine *v4, Q
     if (propertyIdx == -1)
         return OptionalReturnedValue();
 
-    if (propertyIdx < context->idValueCount) {
+    if (propertyIdx < context->numIdValues()) {
         if (hasProperty)
             *hasProperty = true;
 
@@ -104,16 +106,16 @@ static OptionalReturnedValue searchContextProperties(QV4::ExecutionEngine *v4, Q
         }
 
         if (ep->propertyCapture)
-            ep->propertyCapture->captureProperty(&context->idValues[propertyIdx].bindings);
-        return OptionalReturnedValue(QV4::QObjectWrapper::wrap(v4, context->idValues[propertyIdx]));
+            ep->propertyCapture->captureProperty(context->idValueBindings(propertyIdx));
+        return OptionalReturnedValue(QV4::QObjectWrapper::wrap(v4, context->idValue(propertyIdx)));
     }
 
     QQmlContextPrivate *cp = context->asQQmlContextPrivate();
 
     if (ep->propertyCapture)
-        ep->propertyCapture->captureProperty(context->asQQmlContext(), -1, propertyIdx + cp->notifyIndex);
+        ep->propertyCapture->captureProperty(context->asQQmlContext(), -1, propertyIdx + cp->notifyIndex());
 
-    const QVariant &value = cp->propertyValues.at(propertyIdx);
+    const QVariant &value = cp->propertyValue(propertyIdx);
     if (hasProperty)
         *hasProperty = true;
     if (value.userType() == qMetaTypeId<QList<QObject*> >()) {
@@ -122,7 +124,7 @@ static OptionalReturnedValue searchContextProperties(QV4::ExecutionEngine *v4, Q
                                        QQmlContextPrivate::context_at);
         return OptionalReturnedValue(QmlListWrapper::create(v4, prop, qMetaTypeId<QQmlListProperty<QObject> >()));
     }
-    return OptionalReturnedValue(v4->fromVariant(cp->propertyValues.at(propertyIdx)));
+    return OptionalReturnedValue(v4->fromVariant(cp->propertyValue(propertyIdx)));
 }
 
 ReturnedValue QQmlContextWrapper::getPropertyAndBase(const QQmlContextWrapper *resource, PropertyKey id, const Value *receiver, bool *hasProperty, Value *base, Lookup *lookup)
@@ -133,7 +135,7 @@ ReturnedValue QQmlContextWrapper::getPropertyAndBase(const QQmlContextWrapper *r
     QV4::ExecutionEngine *v4 = resource->engine();
     QV4::Scope scope(v4);
 
-    if (v4->callingQmlContext() != *resource->d()->context) {
+    if (v4->callingQmlContext().data() != resource->d()->context) {
         if (resource->d()->module) {
             Scoped<Module> module(scope, resource->d()->module);
             bool hasProp = false;
@@ -158,8 +160,8 @@ ReturnedValue QQmlContextWrapper::getPropertyAndBase(const QQmlContextWrapper *r
 
     // It's possible we could delay the calculation of the "actual" context (in the case
     // of sub contexts) until it is definitely needed.
-    QQmlContextData *context = resource->getContext();
-    QQmlContextData *expressionContext = context;
+    QQmlRefPointer<QQmlContextData> context = resource->getContext();
+    QQmlRefPointer<QQmlContextData> expressionContext = context;
 
     if (!context) {
         if (hasProperty)
@@ -211,9 +213,9 @@ ReturnedValue QQmlContextWrapper::getPropertyAndBase(const QQmlContextWrapper *r
             return result->asReturnedValue();
     }
 
-    if (context->imports && name->startsWithUpper()) {
+    if (context->imports() && name->startsWithUpper()) {
         // Search for attached properties, enums and imported scripts
-        QQmlTypeNameCache::Result r = context->imports->query(name, QQmlImport::AllowRecursion);
+        QQmlTypeNameCache::Result r = context->imports()->query(name, QQmlImport::AllowRecursion);
 
         if (r.isValid()) {
             if (hasProperty)
@@ -224,7 +226,7 @@ ReturnedValue QQmlContextWrapper::getPropertyAndBase(const QQmlContextWrapper *r
                     lookup->qmlContextPropertyGetter = QQmlContextWrapper::lookupScript;
                     return lookup->qmlContextPropertyGetter(lookup, v4, base);
                 }
-                QV4::ScopedObject scripts(scope, context->importedScripts.valueRef());
+                QV4::ScopedObject scripts(scope, context->importedScripts().valueRef());
                 if (scripts)
                     return scripts->get(r.scriptIndex);
                 return QV4::Encode::null();
@@ -250,7 +252,7 @@ ReturnedValue QQmlContextWrapper::getPropertyAndBase(const QQmlContextWrapper *r
                 }
                 result = QQmlTypeWrapper::create(v4, scopeObject, r.type);
             } else if (r.importNamespace) {
-                result = QQmlTypeWrapper::create(v4, scopeObject, context->imports, r.importNamespace);
+                result = QQmlTypeWrapper::create(v4, scopeObject, context->imports(), r.importNamespace);
             }
             if (lookup) {
                 lookup->qmlTypeLookup.qmlTypeWrapper = static_cast<Heap::Object*>(result->heapObject());
@@ -268,7 +270,7 @@ ReturnedValue QQmlContextWrapper::getPropertyAndBase(const QQmlContextWrapper *r
     decltype(lookup->qmlContextPropertyGetter) contextGetterFunction = QQmlContextWrapper::lookupContextObjectProperty;
 
     // minor optimization so we don't potentially try two property lookups on the same object
-    if (scopeObject == context->contextObject) {
+    if (scopeObject == context->contextObject()) {
         scopeObject = nullptr;
         contextGetterFunction = QQmlContextWrapper::lookupScopeObjectProperty;
     }
@@ -310,22 +312,24 @@ ReturnedValue QQmlContextWrapper::getPropertyAndBase(const QQmlContextWrapper *r
 
 
         // Search context object
-        if (context->contextObject) {
+        if (QObject *contextObject = context->contextObject()) {
             bool hasProp = false;
             QQmlPropertyData *propertyData = nullptr;
-            result = QV4::QObjectWrapper::getQmlProperty(v4, context, context->contextObject,
-                                                         name, QV4::QObjectWrapper::CheckRevision, &hasProp, &propertyData);
+            result = QV4::QObjectWrapper::getQmlProperty(v4, context, contextObject,
+                                                         name, QV4::QObjectWrapper::CheckRevision,
+                                                         &hasProp, &propertyData);
             if (hasProp) {
                 if (hasProperty)
                     *hasProperty = true;
                 if (base)
-                    *base = QV4::QObjectWrapper::wrap(v4, context->contextObject);
+                    *base = QV4::QObjectWrapper::wrap(v4, contextObject);
 
                 if (propertyData) {
                     if (lookup) {
-                        QQmlData *ddata = QQmlData::get(context->contextObject, false);
+                        QQmlData *ddata = QQmlData::get(contextObject, false);
                         if (ddata && ddata->propertyCache) {
-                            ScopedValue val(scope, base ? *base : Value::fromReturnedValue(QV4::QObjectWrapper::wrap(v4, context->contextObject)));
+                            ScopedValue val(scope, base ? *base
+                                                        : Value::fromReturnedValue(QV4::QObjectWrapper::wrap(v4, contextObject)));
                             const QObjectWrapper *That = static_cast<const QObjectWrapper *>(val->objectValue());
                             lookup->qobjectLookup.ic = That->internalClass();
                             lookup->qobjectLookup.propertyCache = ddata->propertyCache;
@@ -342,7 +346,7 @@ ReturnedValue QQmlContextWrapper::getPropertyAndBase(const QQmlContextWrapper *r
             }
         }
 
-        context = context->parent;
+        context = context->parent();
 
         // As the hierarchy of contexts is not stable, we can't do accelerated lookups beyond
         // the immediate QML context (of the .qml file).
@@ -370,7 +374,7 @@ ReturnedValue QQmlContextWrapper::getPropertyAndBase(const QQmlContextWrapper *r
             return result->asReturnedValue();
     }
 
-    expressionContext->unresolvedNames = true;
+    expressionContext->setUnresolvedNames(true);
 
     return Encode::undefined();
 }
@@ -402,8 +406,8 @@ bool QQmlContextWrapper::virtualPut(Managed *m, PropertyKey id, const Value &val
 
     // It's possible we could delay the calculation of the "actual" context (in the case
     // of sub contexts) until it is definitely needed.
-    QQmlContextData *context = wrapper->getContext();
-    QQmlContextData *expressionContext = context;
+    QQmlRefPointer<QQmlContextData> context = wrapper->getContext();
+    QQmlRefPointer<QQmlContextData> expressionContext = context;
 
     if (!context)
         return false;
@@ -419,7 +423,7 @@ bool QQmlContextWrapper::virtualPut(Managed *m, PropertyKey id, const Value &val
         if (properties.count()) {
             const int propertyIndex = properties.value(name);
             if (propertyIndex != -1) {
-                if (propertyIndex < context->idValueCount) {
+                if (propertyIndex < context->numIdValues()) {
                     v4->throwError(QLatin1String("left-hand side of assignment operator is not an lvalue"));
                     return false;
                 }
@@ -434,14 +438,15 @@ bool QQmlContextWrapper::virtualPut(Managed *m, PropertyKey id, const Value &val
         scopeObject = nullptr;
 
         // Search context object
-        if (context->contextObject &&
-            QV4::QObjectWrapper::setQmlProperty(v4, context, context->contextObject, name, QV4::QObjectWrapper::CheckRevision, value))
+        if (context->contextObject() &&
+            QV4::QObjectWrapper::setQmlProperty(v4, context, context->contextObject(), name,
+                                                QV4::QObjectWrapper::CheckRevision, value))
             return true;
 
-        context = context->parent;
+        context = context->parent();
     }
 
-    expressionContext->unresolvedNames = true;
+    expressionContext->setUnresolvedNames(true);
 
     QString error = QLatin1String("Invalid write to global property \"") + name->toQString() +
             QLatin1Char('"');
@@ -502,11 +507,11 @@ ReturnedValue QQmlContextWrapper::lookupScript(Lookup *l, ExecutionEngine *engin
     if (!qmlContext)
         return QV4::Encode::null();
 
-    QQmlContextData *context = qmlContext->qmlContext();
+    QQmlRefPointer<QQmlContextData> context = qmlContext->qmlContext();
     if (!context)
         return QV4::Encode::null();
 
-    QV4::ScopedObject scripts(scope, context->importedScripts.valueRef());
+    QV4::ScopedObject scripts(scope, context->importedScripts().valueRef());
     if (!scripts)
         return QV4::Encode::null();
     return scripts->get(l->qmlContextScriptLookup.scriptIndex);
@@ -527,7 +532,7 @@ ReturnedValue QQmlContextWrapper::lookupIdObject(Lookup *l, ExecutionEngine *eng
     if (!qmlContext)
         return QV4::Encode::null();
 
-    QQmlContextData *context = qmlContext->qmlContext();
+    QQmlRefPointer<QQmlContextData> context = qmlContext->qmlContext();
     if (!context)
         return QV4::Encode::null();
 
@@ -535,9 +540,9 @@ ReturnedValue QQmlContextWrapper::lookupIdObject(Lookup *l, ExecutionEngine *eng
     const int objectId = l->qmlContextIdObjectLookup.objectId;
 
     if (qmlEngine->propertyCapture)
-        qmlEngine->propertyCapture->captureProperty(&context->idValues[objectId].bindings);
+        qmlEngine->propertyCapture->captureProperty(context->idValueBindings(objectId));
 
-    return QV4::QObjectWrapper::wrap(engine, context->idValues[objectId]);
+    return QV4::QObjectWrapper::wrap(engine, context->idValue(objectId));
 }
 
 ReturnedValue QQmlContextWrapper::lookupScopeObjectProperty(Lookup *l, ExecutionEngine *engine, Value *base)
@@ -576,11 +581,11 @@ ReturnedValue QQmlContextWrapper::lookupContextObjectProperty(Lookup *l, Executi
     if (!qmlContext)
         return QV4::Encode::undefined();
 
-    QQmlContextData *context = qmlContext->qmlContext();
+    QQmlRefPointer<QQmlContextData> context = qmlContext->qmlContext();
     if (!context)
         return QV4::Encode::undefined();
 
-    QObject *contextObject = context->contextObject;
+    QObject *contextObject = context->contextObject();
     if (!contextObject)
         return QV4::Encode::undefined();
 
@@ -621,11 +626,11 @@ ReturnedValue QQmlContextWrapper::lookupInParentContextHierarchy(Lookup *l, Exec
     if (!qmlContext)
         return QV4::Encode::undefined();
 
-    QQmlContextData *context = qmlContext->qmlContext();
+    QQmlRefPointer<QQmlContextData> context = qmlContext->qmlContext();
     if (!context)
         return QV4::Encode::undefined();
 
-    QQmlContextData *expressionContext = context;
+    QQmlRefPointer<QQmlContextData> expressionContext = context;
 
     QQmlEnginePrivate *ep = QQmlEnginePrivate::get(engine->qmlEngine());
 
@@ -635,18 +640,19 @@ ReturnedValue QQmlContextWrapper::lookupInParentContextHierarchy(Lookup *l, Exec
 
     ScopedValue result(scope);
 
-    for (context = context->parent; context; context = context->parent) {
+    for (context = context->parent(); context; context = context->parent()) {
         if (auto property = searchContextProperties(engine, context, name, nullptr, base, nullptr, nullptr, ep))
             return *property;
 
         // Search context object
-        if (context->contextObject) {
+        if (QObject *contextObject = context->contextObject()) {
             bool hasProp = false;
-            result = QV4::QObjectWrapper::getQmlProperty(engine, context, context->contextObject,
-                                                         name, QV4::QObjectWrapper::CheckRevision, &hasProp);
+            result = QV4::QObjectWrapper::getQmlProperty(
+                        engine, context, contextObject, name,
+                        QV4::QObjectWrapper::CheckRevision, &hasProp);
             if (hasProp) {
                 if (base)
-                    *base = QV4::QObjectWrapper::wrap(engine, context->contextObject);
+                    *base = QV4::QObjectWrapper::wrap(engine, contextObject);
 
                 return result->asReturnedValue();
             }
@@ -658,7 +664,7 @@ ReturnedValue QQmlContextWrapper::lookupInParentContextHierarchy(Lookup *l, Exec
     if (hasProp)
         return result->asReturnedValue();
 
-    expressionContext->unresolvedNames = true;
+    expressionContext->setUnresolvedNames(true);
 
     return Encode::undefined();
 }
@@ -692,11 +698,15 @@ void Heap::QmlContext::init(QV4::ExecutionContext *outerContext, QV4::QQmlContex
     this->activation.set(internalClass->engine, qml->d());
 }
 
-Heap::QmlContext *QmlContext::create(ExecutionContext *parent, QQmlContextData *context, QObject *scopeObject)
+Heap::QmlContext *QmlContext::create(
+        ExecutionContext *parent, QQmlRefPointer<QQmlContextData> context,
+        QObject *scopeObject)
 {
     Scope scope(parent);
 
-    Scoped<QQmlContextWrapper> qml(scope, scope.engine->memoryManager->allocate<QQmlContextWrapper>(context, scopeObject));
+    Scoped<QQmlContextWrapper> qml(
+                scope, scope.engine->memoryManager->allocate<QQmlContextWrapper>(
+                    std::move(context), scopeObject));
     Heap::QmlContext *c = scope.engine->memoryManager->alloc<QmlContext>(parent, qml);
     Q_ASSERT(c->vtable() == staticVTable());
     return c;