Cleanup: Fix const'ness of the property binding validator code

The property validator is supposed to validate the proposed property bindings
and abort type compilation if necessary. As such it is a read-only pass through
the data structures and therefore we make it const. However it does have a
side-effect of collecting some state, which however is "write-only" and
therefore marked as mutable. Those variables are written to, but not read
during this pass.

Change-Id: I6a3655fedbd6691b7498cf82ca1c8e21dd635bd3
Reviewed-by: Lars Knoll <lars.knoll@digia.com>

3 files changed, 16 insertions, 15 deletions

diff --git a/src/qml/compiler/qqmltypecompiler.cpp b/src/qml/compiler/qqmltypecompiler.cpp
index ec8e6ac33c..b249d9ad9e 100644
--- a/src/qml/compiler/qqmltypecompiler.cpp
+++ b/src/qml/compiler/qqmltypecompiler.cpp
@@ -402,7 +402,7 @@ QQmlCompilePass::QQmlCompilePass(QQmlTypeCompiler *typeCompiler)
 {
 }
 
-void QQmlCompilePass::recordError(const QV4::CompiledData::Location &location, const QString &description)
+void QQmlCompilePass::recordError(const QV4::CompiledData::Location &location, const QString &description) const
 {
     QQmlError error;
     error.setLine(location.line);
@@ -1714,7 +1714,7 @@ bool QQmlPropertyValidator::validate()
 {
     if (!validateObject(qmlUnit->indexOfRootObject, /*instantiatingBinding*/0))
         return false;
-    compiler->setDeferredBindingsPerObject(deferredBindingsPerObject);
+    compiler->setDeferredBindingsPerObject(_deferredBindingsPerObject);
     return true;
 }
 
@@ -1752,7 +1752,7 @@ struct BindingFinder
     }
 };
 
-bool QQmlPropertyValidator::validateObject(int objectIndex, const QV4::CompiledData::Binding *instantiatingBinding, bool populatingValueTypeGroupProperty)
+bool QQmlPropertyValidator::validateObject(int objectIndex, const QV4::CompiledData::Binding *instantiatingBinding, bool populatingValueTypeGroupProperty) const
 {
     const QV4::CompiledData::Object *obj = qmlUnit->objectAt(objectIndex);
     if (obj->idIndex != 0)
@@ -2007,12 +2007,12 @@ bool QQmlPropertyValidator::validateObject(int objectIndex, const QV4::CompiledD
     }
 
     if (!deferredBindings.isEmpty())
-        deferredBindingsPerObject.insert(objectIndex, deferredBindings);
+        _deferredBindingsPerObject.insert(objectIndex, deferredBindings);
 
     return true;
 }
 
-bool QQmlPropertyValidator::validateLiteralBinding(QQmlPropertyCache *propertyCache, QQmlPropertyData *property, const QV4::CompiledData::Binding *binding)
+bool QQmlPropertyValidator::validateLiteralBinding(QQmlPropertyCache *propertyCache, QQmlPropertyData *property, const QV4::CompiledData::Binding *binding) const
 {
     if (property->isQList()) {
         recordError(binding->valueLocation, tr("Cannot assign primitives to lists"));
@@ -2288,7 +2288,7 @@ bool QQmlPropertyValidator::validateLiteralBinding(QQmlPropertyCache *propertyCa
     Returns true if from can be assigned to a (QObject) property of type
     to.
 */
-bool QQmlPropertyValidator::canCoerce(int to, QQmlPropertyCache *fromMo)
+bool QQmlPropertyValidator::canCoerce(int to, QQmlPropertyCache *fromMo) const
 {
     QQmlPropertyCache *toMo = enginePrivate->rawPropertyCacheForType(to);
 
@@ -2300,7 +2300,7 @@ bool QQmlPropertyValidator::canCoerce(int to, QQmlPropertyCache *fromMo)
     return false;
 }
 
-bool QQmlPropertyValidator::validateObjectBinding(QQmlPropertyData *property, const QString &propertyName, const QV4::CompiledData::Binding *binding)
+bool QQmlPropertyValidator::validateObjectBinding(QQmlPropertyData *property, const QString &propertyName, const QV4::CompiledData::Binding *binding) const
 {
     if (binding->flags & QV4::CompiledData::Binding::IsOnAssignment) {
         Q_ASSERT(binding->type == QV4::CompiledData::Binding::Type_Object);
diff --git a/src/qml/compiler/qqmltypecompiler_p.h b/src/qml/compiler/qqmltypecompiler_p.h
index 025718dd96..0982058e14 100644
--- a/src/qml/compiler/qqmltypecompiler_p.h
+++ b/src/qml/compiler/qqmltypecompiler_p.h
@@ -116,7 +116,7 @@ struct QQmlCompilePass
 
     QString stringAt(int idx) const { return compiler->stringAt(idx); }
 protected:
-    void recordError(const QV4::CompiledData::Location &location, const QString &description);
+    void recordError(const QV4::CompiledData::Location &location, const QString &description) const;
 
     QQmlTypeCompiler *compiler;
 };
@@ -276,13 +276,13 @@ public:
     virtual QString bindingAsString(int objectIndex, const QV4::CompiledData::Binding *binding) const;
 
 private:
-    bool validateObject(int objectIndex, const QV4::CompiledData::Binding *instantiatingBinding, bool populatingValueTypeGroupProperty = false);
-    bool validateLiteralBinding(QQmlPropertyCache *propertyCache, QQmlPropertyData *property, const QV4::CompiledData::Binding *binding);
-    bool validateObjectBinding(QQmlPropertyData *property, const QString &propertyName, const QV4::CompiledData::Binding *binding);
+    bool validateObject(int objectIndex, const QV4::CompiledData::Binding *instantiatingBinding, bool populatingValueTypeGroupProperty = false) const;
+    bool validateLiteralBinding(QQmlPropertyCache *propertyCache, QQmlPropertyData *property, const QV4::CompiledData::Binding *binding) const;
+    bool validateObjectBinding(QQmlPropertyData *property, const QString &propertyName, const QV4::CompiledData::Binding *binding) const;
 
     bool isComponent(int objectIndex) const { return objectIndexToIdPerComponent.contains(objectIndex); }
 
-    bool canCoerce(int to, QQmlPropertyCache *fromMo);
+    bool canCoerce(int to, QQmlPropertyCache *fromMo) const;
 
     QQmlEnginePrivate *enginePrivate;
     const QV4::CompiledData::Unit *qmlUnit;
@@ -291,9 +291,10 @@ private:
     const QVector<QQmlPropertyCache *> &propertyCaches;
     const QHash<int, QHash<int, int> > objectIndexToIdPerComponent;
     QHash<int, QBitArray> *customParserBindingsPerObject;
-    QHash<int, QBitArray> deferredBindingsPerObject;
 
-    bool _seenObjectWithId;
+    // collected state variables, essentially write-only
+    mutable QHash<int, QBitArray> _deferredBindingsPerObject;
+    mutable bool _seenObjectWithId;
 };
 
 // ### merge with QtQml::JSCodeGen and operate directly on object->functionsAndExpressions once old compiler is gone.
diff --git a/src/qml/qml/qqmlcustomparser_p.h b/src/qml/qml/qqmlcustomparser_p.h
index 15ca126365..88282b1bbc 100644
--- a/src/qml/qml/qqmlcustomparser_p.h
+++ b/src/qml/qml/qqmlcustomparser_p.h
@@ -100,7 +100,7 @@ protected:
 
 private:
     QList<QQmlError> exceptions;
-    QQmlCustomParserCompilerBackend *compiler;
+    const QQmlCustomParserCompilerBackend *compiler;
     Flags m_flags;
     QBiPointer<const QQmlImports, QQmlTypeNameCache> imports;
     friend class QQmlPropertyValidator;