Add Qt.callLater() function.

Calling the new Qt.callLater() multiple times in quick succession with the same
JS function as argument will result in a single call to that function, thus
eliminating redundant unnecessary calls.

Based on previous patches by Mathias Malmqvist <mathias.malmqvist@nokia.com>
and Chris Adams <chris.adams@jollamobile.com>

Change-Id: Ie71b60d4d48fa73d3deae723775cf36662d199ae
Task-number: QTBUG-22400
Reviewed-by: Simon Hausmann <simon.hausmann@theqtcompany.com>

1 files changed, 104 insertions, 0 deletions

diff --git a/src/qml/qml/qqmldelayedcallqueue_p.h b/src/qml/qml/qqmldelayedcallqueue_p.h
new file mode 100644
index 0000000000..7eb014cfdf
--- /dev/null
+++ b/src/qml/qml/qqmldelayedcallqueue_p.h
@@ -0,0 +1,104 @@
+/****************************************************************************
+**
+** Copyright (C) 2016 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the QtQml module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU Lesser General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU Lesser
+** General Public License version 3 as published by the Free Software
+** Foundation and appearing in the file LICENSE.LGPL3 included in the
+** packaging of this file. Please review the following information to
+** ensure the GNU Lesser General Public License version 3 requirements
+** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 2.0 or (at your option) the GNU General
+** Public license version 3 or any later version approved by the KDE Free
+** Qt Foundation. The licenses are as published by the Free Software
+** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-2.0.html and
+** https://www.gnu.org/licenses/gpl-3.0.html.
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef QQMLDELAYEDCALLQUEUE_P_H
+#define QQMLDELAYEDCALLQUEUE_P_H
+
+//
+//  W A R N I N G
+//  -------------
+//
+// This file is not part of the Qt API.  It exists purely as an
+// implementation detail.  This header file may change from version to
+// version without notice, or even be removed.
+//
+// We mean it.
+//
+
+#include <QtCore/qglobal.h>
+#include <QtCore/qobject.h>
+#include <QtCore/qmetaobject.h>
+#include <QtCore/qmetatype.h>
+#include <private/qqmlguard_p.h>
+#include <private/qv4context_p.h>
+
+QT_BEGIN_NAMESPACE
+
+class QV8Engine;
+class QQmlDelayedCallQueue : public QObject
+{
+    Q_OBJECT
+public:
+    QQmlDelayedCallQueue();
+    ~QQmlDelayedCallQueue();
+
+    void init(QV4::ExecutionEngine *);
+
+    QV4::ReturnedValue addUniquelyAndExecuteLater(QV4::CallContext *ctx);
+
+public Q_SLOTS:
+    void ticked();
+
+private:
+    struct DelayedFunctionCall
+    {
+        DelayedFunctionCall() {}
+        DelayedFunctionCall(QV4::PersistentValue function)
+            : m_function(function), m_guarded(false) { }
+
+        void execute(QV4::ExecutionEngine *engine) const;
+
+        QV4::PersistentValue m_function;
+        QList<QV4::PersistentValue> m_args;
+        QQmlGuard<QObject> m_objectGuard;
+        bool m_guarded;
+    };
+
+    void storeAnyArguments(DelayedFunctionCall& dfc, const QV4::CallData *callData, int offset, QV4::ExecutionEngine *engine);
+    void executeAllExpired_Later();
+
+    QV4::ExecutionEngine *m_engine;
+    QVector<DelayedFunctionCall> m_delayedFunctionCalls;
+    QMetaMethod m_tickedMethod;
+    bool m_callbackOutstanding;
+};
+
+QT_END_NAMESPACE
+
+#endif // QQMLDELAYEDCALLQUEUE_P_H