Remove dead compile time QML context/scope property and id object code

After enabling lookups in QML files, we can remove all the code that
tries to deal with (type) compile time detection of access to id objects
and properties of the scope/context object. This also allows removing
quite a bit of run-time code paths and even byte code instructions.

Task-number: QTBUG-69898
Change-Id: I7b26d7983393594a3ef56466d3e633f1822b76f4
Reviewed-by: Ulf Hermann <ulf.hermann@qt.io>

3 files changed, 21 insertions, 114 deletions

diff --git a/src/qml/qml/qqmlbinding.cpp b/src/qml/qml/qqmlbinding.cpp
index eea3670191..7f0442d034 100644
--- a/src/qml/qml/qqmlbinding.cpp
+++ b/src/qml/qml/qqmlbinding.cpp
@@ -260,8 +260,6 @@ protected:
             } else {
                 clearError();
             }
-
-            cancelPermanentGuards();
         }
 
         ep->dereferenceScarceResources();
@@ -643,24 +641,22 @@ QVector<QQmlProperty> QQmlBinding::dependencies() const
     if (!m_target.data())
         return dependencies;
 
-    for (const auto &guardList : { permanentGuards, activeGuards }) {
-        for (QQmlJavaScriptExpressionGuard *guard = guardList.first(); guard; guard = guardList.next(guard)) {
-            if (guard->signalIndex() == -1) // guard's sender is a QQmlNotifier, not a QObject*.
-                continue;
+    for (QQmlJavaScriptExpressionGuard *guard = activeGuards.first(); guard; guard = activeGuards.next(guard)) {
+        if (guard->signalIndex() == -1) // guard's sender is a QQmlNotifier, not a QObject*.
+            continue;
 
-            QObject *senderObject = guard->senderAsObject();
-            if (!senderObject)
-                continue;
+        QObject *senderObject = guard->senderAsObject();
+        if (!senderObject)
+            continue;
 
-            const QMetaObject *senderMeta = senderObject->metaObject();
-            if (!senderMeta)
-                continue;
+        const QMetaObject *senderMeta = senderObject->metaObject();
+        if (!senderMeta)
+            continue;
 
-            for (int i = 0; i < senderMeta->propertyCount(); i++) {
-                QMetaProperty property = senderMeta->property(i);
-                if (property.notifySignalIndex() == QMetaObjectPrivate::signal(senderMeta, guard->signalIndex()).methodIndex()) {
-                    dependencies.push_back(QQmlProperty(senderObject, QString::fromUtf8(senderObject->metaObject()->property(i).name())));
-                }
+        for (int i = 0; i < senderMeta->propertyCount(); i++) {
+            QMetaProperty property = senderMeta->property(i);
+            if (property.notifySignalIndex() == QMetaObjectPrivate::signal(senderMeta, guard->signalIndex()).methodIndex()) {
+                dependencies.push_back(QQmlProperty(senderObject, QString::fromUtf8(senderObject->metaObject()->property(i).name())));
             }
         }
     }
@@ -670,7 +666,7 @@ QVector<QQmlProperty> QQmlBinding::dependencies() const
 
 bool QQmlBinding::hasDependencies() const
 {
-    return !permanentGuards.isEmpty() || !activeGuards.isEmpty() || translationsCaptured();
+    return !activeGuards.isEmpty() || translationsCaptured();
 }
 
 class QObjectPointerBinding: public QQmlNonbindingBinding
diff --git a/src/qml/qml/qqmljavascriptexpression.cpp b/src/qml/qml/qqmljavascriptexpression.cpp
index 380163202a..9a3a5218e0 100644
--- a/src/qml/qml/qqmljavascriptexpression.cpp
+++ b/src/qml/qml/qqmljavascriptexpression.cpp
@@ -109,7 +109,6 @@ QQmlJavaScriptExpression::~QQmlJavaScriptExpression()
     }
 
     clearActiveGuards();
-    clearPermanentGuards();
     clearError();
     if (m_scopeObject.isT2()) // notify DeleteWatcher of our deletion.
         m_scopeObject.asT2()->_s = nullptr;
@@ -118,12 +117,8 @@ QQmlJavaScriptExpression::~QQmlJavaScriptExpression()
 void QQmlJavaScriptExpression::setNotifyOnValueChanged(bool v)
 {
     activeGuards.setFlagValue(v);
-    permanentGuards.setFlagValue(v);
-    if (!v) {
+    if (!v)
         clearActiveGuards();
-        clearPermanentGuards();
-        m_permanentDependenciesRegistered = false;
-    }
 }
 
 void QQmlJavaScriptExpression::resetNotifyOnValueChanged()
@@ -216,10 +211,6 @@ QV4::ReturnedValue QQmlJavaScriptExpression::evaluate(QV4::CallData *callData, b
     QV4::ReturnedValue res = v4Function->call(&callData->thisObject, callData->args, callData->argc(), static_cast<QV4::ExecutionContext *>(m_qmlScope.valueRef()));
     QV4::Scope scope(v4);
     QV4::ScopedValue result(scope, res);
-    if (v4Function->hasQmlDependencies) {
-        QV4::Heap::QmlContext *qc = m_qmlScope.as<QV4::QmlContext>()->d();
-        QQmlPropertyCapture::registerQmlDependencies(qc, v4, v4Function->compiledFunction);
-    }
 
     if (scope.hasException()) {
         if (watcher.wasDeleted())
@@ -254,7 +245,7 @@ QV4::ReturnedValue QQmlJavaScriptExpression::evaluate(QV4::CallData *callData, b
     return result->asReturnedValue();
 }
 
-void QQmlPropertyCapture::captureProperty(QQmlNotifier *n, Duration duration)
+void QQmlPropertyCapture::captureProperty(QQmlNotifier *n)
 {
     if (watcher->wasDeleted())
         return;
@@ -274,17 +265,14 @@ void QQmlPropertyCapture::captureProperty(QQmlNotifier *n, Duration duration)
         g->connect(n);
     }
 
-    if (duration == Permanently)
-        expression->permanentGuards.prepend(g);
-    else
-        expression->activeGuards.prepend(g);
+    expression->activeGuards.prepend(g);
 }
 
 /*! \internal
 
     \a n is in the signal index range (see QObjectPrivate::signalIndex()).
 */
-void QQmlPropertyCapture::captureProperty(QObject *o, int c, int n, Duration duration, bool doNotify)
+void QQmlPropertyCapture::captureProperty(QObject *o, int c, int n, bool doNotify)
 {
     if (watcher->wasDeleted())
         return;
@@ -323,61 +311,8 @@ void QQmlPropertyCapture::captureProperty(QObject *o, int c, int n, Duration dur
             g->connect(o, n, engine, doNotify);
         }
 
-        if (duration == Permanently)
-            expression->permanentGuards.prepend(g);
-        else
-            expression->activeGuards.prepend(g);
-    }
-}
-
-void QQmlPropertyCapture::registerQmlDependencies(QV4::Heap::QmlContext *context, const QV4::ExecutionEngine *engine, const QV4::CompiledData::Function *compiledFunction)
-{
-    // Let the caller check and avoid the function call :)
-    Q_ASSERT(compiledFunction->hasQmlDependencies());
-
-    QQmlEnginePrivate *ep = QQmlEnginePrivate::get(engine->qmlEngine());
-    if (!ep)
-        return;
-    QQmlPropertyCapture *capture = ep->propertyCapture;
-    if (!capture || capture->watcher->wasDeleted())
-        return;
-
-    if (capture->expression->m_permanentDependenciesRegistered)
-        return;
-
-    capture->expression->m_permanentDependenciesRegistered = true;
-
-    QV4::Heap::QQmlContextWrapper *wrapper = context->qml();
-    QQmlContextData *qmlContext = wrapper->context->contextData();
-
-    const quint32_le *idObjectDependency = compiledFunction->qmlIdObjectDependencyTable();
-    const int idObjectDependencyCount = compiledFunction->nDependingIdObjects;
-    for (int i = 0; i < idObjectDependencyCount; ++i, ++idObjectDependency) {
-        Q_ASSERT(int(*idObjectDependency) < qmlContext->idValueCount);
-        capture->captureProperty(&qmlContext->idValues[*idObjectDependency].bindings,
-                                 QQmlPropertyCapture::Permanently);
-    }
-
-    Q_ASSERT(qmlContext->contextObject);
-    const quint32_le *contextPropertyDependency = compiledFunction->qmlContextPropertiesDependencyTable();
-    const int contextPropertyDependencyCount = compiledFunction->nDependingContextProperties;
-    for (int i = 0; i < contextPropertyDependencyCount; ++i) {
-        const int propertyIndex = *contextPropertyDependency++;
-        const int notifyIndex = *contextPropertyDependency++;
-        capture->captureProperty(qmlContext->contextObject, propertyIndex, notifyIndex,
-                                 QQmlPropertyCapture::Permanently);
-    }
-
-    QObject *scopeObject = wrapper->scopeObject;
-    const quint32_le *scopePropertyDependency = compiledFunction->qmlScopePropertiesDependencyTable();
-    const int scopePropertyDependencyCount = compiledFunction->nDependingScopeProperties;
-    for (int i = 0; i < scopePropertyDependencyCount; ++i) {
-        const int propertyIndex = *scopePropertyDependency++;
-        const int notifyIndex = *scopePropertyDependency++;
-        capture->captureProperty(scopeObject, propertyIndex, notifyIndex,
-                                 QQmlPropertyCapture::Permanently);
+        expression->activeGuards.prepend(g);
     }
-
 }
 
 QQmlError QQmlJavaScriptExpression::error(QQmlEngine *engine) const
@@ -471,13 +406,6 @@ void QQmlJavaScriptExpression::clearActiveGuards()
         g->Delete();
 }
 
-void QQmlJavaScriptExpression::clearPermanentGuards()
-{
-    m_permanentDependenciesRegistered = false;
-    while (QQmlJavaScriptExpressionGuard *g = permanentGuards.takeFirst())
-        g->Delete();
-}
-
 void QQmlJavaScriptExpressionGuard_callback(QQmlNotifierEndpoint *e, void **)
 {
     QQmlJavaScriptExpression *expression =
diff --git a/src/qml/qml/qqmljavascriptexpression_p.h b/src/qml/qml/qqmljavascriptexpression_p.h
index de3fba0774..453c8ab8a8 100644
--- a/src/qml/qml/qqmljavascriptexpression_p.h
+++ b/src/qml/qml/qqmljavascriptexpression_p.h
@@ -144,7 +144,6 @@ public:
     QQmlError error(QQmlEngine *) const;
     void clearError();
     void clearActiveGuards();
-    void clearPermanentGuards();
     QQmlDelayedError *delayedError();
 
     static QV4::ReturnedValue evalFunction(QQmlContextData *ctxt, QObject *scope,
@@ -153,14 +152,6 @@ public:
 protected:
     void createQmlBinding(QQmlContextData *ctxt, QObject *scope, const QString &code, const QString &filename, quint16 line);
 
-    void cancelPermanentGuards() const
-    {
-        if (m_permanentDependenciesRegistered) {
-            for (QQmlJavaScriptExpressionGuard *it = permanentGuards.first(); it; it = permanentGuards.next(it))
-                it->cancelNotify();
-        }
-    }
-
     void setupFunction(QV4::ExecutionContext *qmlContext, QV4::Function *f);
     void setCompilationUnit(const QQmlRefPointer<QV4::CompiledData::CompilationUnit> &compilationUnit);
 
@@ -169,7 +160,6 @@ protected:
     //    activeGuards:flag2  - useSharedContext
     QBiPointer<QObject, DeleteWatcher> m_scopeObject;
     QForwardFieldList<QQmlJavaScriptExpressionGuard, &QQmlJavaScriptExpressionGuard::next> activeGuards;
-    QForwardFieldList<QQmlJavaScriptExpressionGuard, &QQmlJavaScriptExpressionGuard::next> permanentGuards;
 
     void setTranslationsCaptured(bool captured) { m_error.setFlagValue(captured); }
     bool translationsCaptured() const { return m_error.flag(); }
@@ -186,7 +176,6 @@ private:
     QQmlContextData *m_context;
     QQmlJavaScriptExpression **m_prevExpression;
     QQmlJavaScriptExpression  *m_nextExpression;
-    bool m_permanentDependenciesRegistered = false;
 
     QV4::PersistentValue m_qmlScope;
     QQmlRefPointer<QV4::CompiledData::CompilationUnit> m_compilationUnit;
@@ -204,14 +193,8 @@ public:
         Q_ASSERT(errorString == nullptr);
     }
 
-    enum Duration {
-        OnlyOnce,
-        Permanently
-    };
-
-    static void registerQmlDependencies(QV4::Heap::QmlContext *context, const QV4::ExecutionEngine *engine, const QV4::CompiledData::Function *compiledFunction);
-    void captureProperty(QQmlNotifier *, Duration duration = OnlyOnce);
-    void captureProperty(QObject *, int, int, Duration duration = OnlyOnce, bool doNotify = true);
+    void captureProperty(QQmlNotifier *);
+    void captureProperty(QObject *, int, int, bool doNotify = true);
     void captureTranslation() { translationCaptured = true; }
 
     QQmlEngine *engine;