Abstract expression and binding APIs

By splitting the interface through which the system interacts with bindings
away from a specific implementation, we can introduce highly specialized
implementations for specific optimizations.

This commit also includes a sample optimization for object properties being
assigned directly from a local id.

1 files changed, 109 insertions, 0 deletions

diff --git a/src/declarative/qml/qmlbindingoptimizations.cpp b/src/declarative/qml/qmlbindingoptimizations.cpp
new file mode 100644
index 0000000..235c034
--- /dev/null
+++ b/src/declarative/qml/qmlbindingoptimizations.cpp
@@ -0,0 +1,109 @@
+/****************************************************************************
+**
+** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
+** Contact: Qt Software Information (qt-info@nokia.com)
+**
+** This file is part of the QtDeclarative module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** No Commercial Usage
+** This file contains pre-release code and may not be distributed.
+** You may use this file in accordance with the terms and conditions
+** contained in the either Technology Preview License Agreement or the
+** Beta Release License Agreement.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 2.1 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU Lesser General Public License version 2.1 requirements
+** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
+**
+** In addition, as a special exception, Nokia gives you certain
+** additional rights. These rights are described in the Nokia Qt LGPL
+** Exception version 1.0, included in the file LGPL_EXCEPTION.txt in this
+** package.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3.0 as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL included in the
+** packaging of this file.  Please review the following information to
+** ensure the GNU General Public License version 3.0 requirements will be
+** met: http://www.gnu.org/copyleft/gpl.html.
+**
+** If you are unsure which license is appropriate for your use, please
+** contact the sales department at qt-sales@nokia.com.
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include "qmlbindingoptimizations_p.h"
+#include <private/qmlcontext_p.h>
+
+QT_BEGIN_NAMESPACE
+
+
+QmlBindingIdOptimization::QmlBindingIdOptimization(QObject *object, 
+                                                   int propertyIdx,
+                                                   QmlContext *context, 
+                                                   int id)
+: m_prev(0), m_next(0), m_object(object), m_propertyIdx(propertyIdx), m_id(id)
+{
+    QmlAbstractExpression::setContext(context);
+}
+
+void QmlBindingIdOptimization::setEnabled(bool e)
+{
+    if (e) {
+        addToObject(m_object);
+        update();
+    } else {
+        removeFromObject();
+    }
+}
+
+int QmlBindingIdOptimization::propertyIndex()
+{
+    return m_propertyIdx;
+}
+
+void QmlBindingIdOptimization::update()
+{
+    QmlContextPrivate *ctxtPriv = 
+        static_cast<QmlContextPrivate *>(QObjectPrivate::get(context()));
+
+    if (ctxtPriv) {
+
+        if (!m_prev) {
+            m_next = ctxtPriv->idValues[m_id].bindings;
+            if (m_next) m_next->m_prev = &m_next;
+
+            m_prev = &ctxtPriv->idValues[m_id].bindings;
+            ctxtPriv->idValues[m_id].bindings = this;
+        }
+
+        QObject *o = ctxtPriv->idValues[m_id].data();
+        void *a[] = { &o, 0 };
+        QMetaObject::metacall(m_object, QMetaObject::WriteProperty, 
+                              m_propertyIdx, a);
+    } 
+}
+
+void QmlBindingIdOptimization::reset()
+{
+    if (m_prev) {
+        *m_prev = m_next;
+        if (m_next) m_next->m_prev = m_prev;
+        m_next = 0;
+        m_prev = 0;
+    }
+
+    QObject *o = 0;
+    void *a[] = { &o, 0 };
+    QMetaObject::metacall(m_object, QMetaObject::WriteProperty, 
+                          m_propertyIdx, a);
+}
+
+QT_END_NAMESPACE