Optimized QDeclarativeScriptString constructor for QDeclarativeExpression.

When the compiler sees a script string, it will attempt to rewrite it
and store the id for the rewrite in the script string. We can then
create a QDeclarativeExpression using the id, which saves us a rewrite
at runtime.

Reviewed-by: Aaron Kennedy

14 files changed, 279 insertions, 15 deletions

diff --git a/doc/src/declarative/whatsnew.qdoc b/doc/src/declarative/whatsnew.qdoc
index bcf27e1a40..2ce16eea40 100644
--- a/doc/src/declarative/whatsnew.qdoc
+++ b/doc/src/declarative/whatsnew.qdoc
@@ -40,6 +40,9 @@ You can still ignore these events in the handler to let them pass through.
 The Binding element now restores any previously set binding when its \e when
 clause becomes false.
 
+QDeclarativeExpression can now be directly (and more efficiently) constructed from a
+QDeclarativeScriptString.
+
 \section1 Qt 4.7.4 includes QtQuick 1.1
 
 QtQuick 1.1 is a minor feature update.  \e {import QtQuick 1.1} to use the new
diff --git a/src/declarative/qml/qdeclarativecompiler.cpp b/src/declarative/qml/qdeclarativecompiler.cpp
index e66a3fe792..72010c0ef2 100644
--- a/src/declarative/qml/qdeclarativecompiler.cpp
+++ b/src/declarative/qml/qdeclarativecompiler.cpp
@@ -1012,12 +1012,14 @@ void QDeclarativeCompiler::genObjectBody(QDeclarativeParser::Object *obj)
 {
     typedef QPair<Property *, int> PropPair;
     foreach(const PropPair &prop, obj->scriptStringProperties) {
+        const QString &script = prop.first->values.at(0)->value.asScript();
         QDeclarativeInstruction ss;
         ss.setType(QDeclarativeInstruction::StoreScriptString);
         ss.storeScriptString.propertyIndex = prop.first->index;
-        ss.storeScriptString.value = 
-            output->indexForString(prop.first->values.at(0)->value.asScript());
+        ss.storeScriptString.value = output->indexForString(script);
         ss.storeScriptString.scope = prop.second;
+        ss.storeScriptString.bindingId = rewriteBinding(script, prop.first->name);
+        ss.storeScriptString.line = prop.first->location.start.line;
         output->addInstruction(ss);
     }
 
diff --git a/src/declarative/qml/qdeclarativeexpression.cpp b/src/declarative/qml/qdeclarativeexpression.cpp
index 247bde9a6c..8079cf3eea 100644
--- a/src/declarative/qml/qdeclarativeexpression.cpp
+++ b/src/declarative/qml/qdeclarativeexpression.cpp
@@ -45,6 +45,7 @@
 #include "private/qdeclarativeengine_p.h"
 #include "private/qdeclarativecontext_p.h"
 #include "private/qdeclarativerewrite_p.h"
+#include "private/qdeclarativescriptstring_p.h"
 #include "private/qdeclarativecompiler_p.h"
 #include "private/qdeclarativeglobalscriptclass_p.h"
 
@@ -271,6 +272,58 @@ QDeclarativeExpression::QDeclarativeExpression(QDeclarativeContextData *ctxt, vo
 /*!
     Create a QDeclarativeExpression object that is a child of \a parent.
 
+    The \script provides the expression to be evaluated, the context to evaluate it in,
+    and the scope object to evaluate it with.
+
+    This constructor is functionally equivalent to the following, but in most cases
+    is more efficient.
+    \code
+    QDeclarativeExpression expression(script.context(), script.scopeObject(), script.script(), parent);
+    \endcode
+
+    \sa QDeclarativeScriptString
+*/
+QDeclarativeExpression::QDeclarativeExpression(const QDeclarativeScriptString &script, QObject *parent)
+: QObject(*new QDeclarativeExpressionPrivate, parent)
+{
+    Q_D(QDeclarativeExpression);
+    bool defaultConstruction = false;
+
+    int id = script.d.data()->bindingId;
+    if (id < 0) {
+        defaultConstruction = true;
+    } else {
+        QDeclarativeContextData *ctxtdata = QDeclarativeContextData::get(script.context());
+
+        QDeclarativeEnginePrivate *engine = QDeclarativeEnginePrivate::get(qmlEngine(script.scopeObject()));
+        QDeclarativeCompiledData *cdata = 0;
+        QDeclarativeTypeData *typeData = 0;
+        if (engine && ctxtdata && !ctxtdata->url.isEmpty()) {
+            typeData = engine->typeLoader.get(ctxtdata->url);
+            cdata = typeData->compiledData();
+        }
+
+        if (cdata)
+            d->init(ctxtdata, (void*)cdata->datas.at(id).constData(), cdata, script.scopeObject(),
+                    cdata->name, script.d.data()->lineNumber);
+        else
+           defaultConstruction = true;
+
+        if (typeData)
+            typeData->release();
+    }
+
+    if (defaultConstruction)
+        d->init(QDeclarativeContextData::get(script.context()), script.script(), script.scopeObject());
+
+    if (QDeclarativeExpression_notifyIdx == -1)
+        QDeclarativeExpression_notifyIdx = QDeclarativeExpression::staticMetaObject.indexOfMethod("_q_notify()");
+    d->setNotifyObject(this, QDeclarativeExpression_notifyIdx);
+}
+
+/*!
+    Create a QDeclarativeExpression object that is a child of \a parent.
+
     The \a expression JavaScript will be executed in the \a ctxt QDeclarativeContext.
     If specified, the \a scope object's properties will also be in scope during
     the expression's execution.
diff --git a/src/declarative/qml/qdeclarativeexpression.h b/src/declarative/qml/qdeclarativeexpression.h
index fef97de2b2..b76205c82e 100644
--- a/src/declarative/qml/qdeclarativeexpression.h
+++ b/src/declarative/qml/qdeclarativeexpression.h
@@ -43,6 +43,7 @@
 #define QDECLARATIVEEXPRESSION_H
 
 #include <QtDeclarative/qdeclarativeerror.h>
+#include <QtDeclarative/qdeclarativescriptstring.h>
 
 #include <QtCore/qobject.h>
 #include <QtCore/qvariant.h>
@@ -66,6 +67,7 @@ class Q_DECLARATIVE_EXPORT QDeclarativeExpression : public QObject
 public:
     QDeclarativeExpression();
     QDeclarativeExpression(QDeclarativeContext *, QObject *, const QString &, QObject * = 0);
+    explicit QDeclarativeExpression(const QDeclarativeScriptString &, QObject * = 0);
     virtual ~QDeclarativeExpression();
 
     QDeclarativeEngine *engine() const;
diff --git a/src/declarative/qml/qdeclarativeinstruction.cpp b/src/declarative/qml/qdeclarativeinstruction.cpp
index fa0d8ea6f4..79a2a1cc34 100644
--- a/src/declarative/qml/qdeclarativeinstruction.cpp
+++ b/src/declarative/qml/qdeclarativeinstruction.cpp
@@ -160,7 +160,7 @@ void QDeclarativeCompiledData::dump(QDeclarativeInstruction *instr, int idx)
         qWarning().nospace() << idx << "\t\t" << "STORE_IMPORTED_SCRIPT\t" << instr->storeScript.value;
         break;
     case QDeclarativeInstruction::StoreScriptString:
-        qWarning().nospace() << idx << "\t\t" << "STORE_SCRIPT_STRING\t" << instr->storeScriptString.propertyIndex << "\t" << instr->storeScriptString.value << "\t" << instr->storeScriptString.scope;
+        qWarning().nospace() << idx << "\t\t" << "STORE_SCRIPT_STRING\t" << instr->storeScriptString.propertyIndex << "\t" << instr->storeScriptString.value << "\t" << instr->storeScriptString.scope << "\t" << instr->storeScriptString.bindingId;
         break;
     case QDeclarativeInstruction::AssignSignalObject:
         qWarning().nospace() << idx << "\t\t" << "ASSIGN_SIGNAL_OBJECT\t" << instr->assignSignalObject.signal << "\t\t\t" << datas.at(instr->assignSignalObject.signal);
diff --git a/src/declarative/qml/qdeclarativeinstruction_p.h b/src/declarative/qml/qdeclarativeinstruction_p.h
index d040967882..3db55a66d3 100644
--- a/src/declarative/qml/qdeclarativeinstruction_p.h
+++ b/src/declarative/qml/qdeclarativeinstruction_p.h
@@ -245,6 +245,8 @@ union QDeclarativeInstruction
         int propertyIndex;
         int value;
         int scope;
+        int bindingId;
+        ushort line;
     }; 
     struct instr_storeScript {
         QML_INSTR_HEADER
diff --git a/src/declarative/qml/qdeclarativescriptstring.cpp b/src/declarative/qml/qdeclarativescriptstring.cpp
index f544393b9b..02d6e5603e 100644
--- a/src/declarative/qml/qdeclarativescriptstring.cpp
+++ b/src/declarative/qml/qdeclarativescriptstring.cpp
@@ -40,19 +40,10 @@
 ****************************************************************************/
 
 #include "qdeclarativescriptstring.h"
+#include "qdeclarativescriptstring_p.h"
 
 QT_BEGIN_NAMESPACE
 
-class QDeclarativeScriptStringPrivate : public QSharedData
-{
-public:
-    QDeclarativeScriptStringPrivate() : context(0), scope(0) {}
-
-    QDeclarativeContext *context;
-    QObject *scope;
-    QString script;
-};
-
 /*!
 \class QDeclarativeScriptString
 \since 4.7
@@ -75,8 +66,8 @@ and the class could choose how to handle it. Typically, the class will evaluate
 the script at some later time using a QDeclarativeExpression.
 
 \code
-QDeclarativeExpression expr(scriptString.context(), scriptString.script(), scriptStr.scopeObject());
-expr.value();
+QDeclarativeExpression expr(scriptString);
+expr.evaluate();
 \endcode
 
 \sa QDeclarativeExpression
diff --git a/src/declarative/qml/qdeclarativescriptstring.h b/src/declarative/qml/qdeclarativescriptstring.h
index 5408dd404d..5f3a2fe73f 100644
--- a/src/declarative/qml/qdeclarativescriptstring.h
+++ b/src/declarative/qml/qdeclarativescriptstring.h
@@ -75,6 +75,9 @@ public:
 
 private:
     QSharedDataPointer<QDeclarativeScriptStringPrivate> d;
+
+    friend class QDeclarativeVME;
+    friend class QDeclarativeExpression;
 };
 
 QT_END_NAMESPACE
diff --git a/src/declarative/qml/qdeclarativescriptstring_p.h b/src/declarative/qml/qdeclarativescriptstring_p.h
new file mode 100644
index 0000000000..cd0cc43995
--- /dev/null
+++ b/src/declarative/qml/qdeclarativescriptstring_p.h
@@ -0,0 +1,63 @@
+/****************************************************************************
+**
+** Copyright (C) 2011 Nokia Corporation and/or its subsidiary(-ies).
+** All rights reserved.
+** Contact: Nokia Corporation (qt-info@nokia.com)
+**
+** This file is part of the QtDeclarative module of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** GNU Lesser General Public License Usage
+** 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 1.1, 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.
+**
+** Other Usage
+** Alternatively, this file may be used in accordance with the terms and
+** conditions contained in a signed written agreement between you and Nokia.
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#ifndef QDECLARATIVESCRIPTSTRING_P_H
+#define QDECLARATIVESCRIPTSTRING_P_H
+
+#include <QtDeclarative/qdeclarativecontext.h>
+
+QT_BEGIN_NAMESPACE
+
+class QDeclarativeScriptStringPrivate : public QSharedData
+{
+public:
+    QDeclarativeScriptStringPrivate() : context(0), scope(0), bindingId(-1), lineNumber(-1) {}
+
+    QDeclarativeContext *context;
+    QObject *scope;
+    QString script;
+    int bindingId;
+    int lineNumber;
+};
+
+QT_END_NAMESPACE
+
+#endif // QDECLARATIVESCRIPTSTRING_P_H
diff --git a/src/declarative/qml/qdeclarativevme.cpp b/src/declarative/qml/qdeclarativevme.cpp
index dd080a85e9..a9b303c94f 100644
--- a/src/declarative/qml/qdeclarativevme.cpp
+++ b/src/declarative/qml/qdeclarativevme.cpp
@@ -61,6 +61,7 @@
 #include "private/qdeclarativeglobal_p.h"
 #include "private/qdeclarativeglobalscriptclass_p.h"
 #include "qdeclarativescriptstring.h"
+#include "qdeclarativescriptstring_p.h"
 
 #include <QStack>
 #include <QWidget>
@@ -640,6 +641,8 @@ QObject *QDeclarativeVME::run(QDeclarativeVMEStack<QObject *> &stack,
             ss.setContext(ctxt->asQDeclarativeContext());
             ss.setScopeObject(scope);
             ss.setScript(primitives.at(instr.value));
+            ss.d.data()->bindingId = instr.bindingId;
+            ss.d.data()->lineNumber = instr.line;
 
             void *a[] = { &ss, 0, &status, &flags };
             QMetaObject::metacall(target, QMetaObject::WriteProperty, 
diff --git a/src/declarative/qml/qml.pri b/src/declarative/qml/qml.pri
index 233359079d..5d56b300ba 100644
--- a/src/declarative/qml/qml.pri
+++ b/src/declarative/qml/qml.pri
@@ -129,6 +129,7 @@ HEADERS += \
     $$PWD/qdeclarativeimport_p.h \
     $$PWD/qdeclarativeextensionplugin.h \
     $$PWD/qintrusivelist_p.h \
+    $$PWD/qdeclarativescriptstring_p.h
 
 QT += sql
 include(parser/parser.pri)
diff --git a/tests/auto/declarative/qdeclarativeexpression/data/scriptString.qml b/tests/auto/declarative/qdeclarativeexpression/data/scriptString.qml
new file mode 100644
index 0000000000..edd4048cc1
--- /dev/null
+++ b/tests/auto/declarative/qdeclarativeexpression/data/scriptString.qml
@@ -0,0 +1,9 @@
+import QtQuick 1.0
+import Test 1.0
+
+TestObject {
+    property int value1: 10
+    property int value2: 5
+    scriptString: value1 + value2
+    scriptStringError: value3 * 5
+}
diff --git a/tests/auto/declarative/qdeclarativeexpression/qdeclarativeexpression.pro b/tests/auto/declarative/qdeclarativeexpression/qdeclarativeexpression.pro
new file mode 100644
index 0000000000..8c73a7cb87
--- /dev/null
+++ b/tests/auto/declarative/qdeclarativeexpression/qdeclarativeexpression.pro
@@ -0,0 +1,17 @@
+load(qttest_p4)
+contains(QT_CONFIG,declarative): QT += declarative gui
+macx:CONFIG -= app_bundle
+
+SOURCES += tst_qdeclarativeexpression.cpp
+
+symbian: {
+    importFiles.files = data
+    importFiles.path = .
+    DEPLOYMENT += importFiles
+} else {
+    DEFINES += SRCDIR=\\\"$$PWD\\\"
+}
+
+CONFIG += parallel_test
+
+QT += core-private gui-private declarative-private
diff --git a/tests/auto/declarative/qdeclarativeexpression/tst_qdeclarativeexpression.cpp b/tests/auto/declarative/qdeclarativeexpression/tst_qdeclarativeexpression.cpp
new file mode 100644
index 0000000000..aa8c12e332
--- /dev/null
+++ b/tests/auto/declarative/qdeclarativeexpression/tst_qdeclarativeexpression.cpp
@@ -0,0 +1,115 @@
+/****************************************************************************
+**
+** Copyright (C) 2011 Nokia Corporation and/or its subsidiary(-ies).
+** All rights reserved.
+** Contact: Nokia Corporation (qt-info@nokia.com)
+**
+** This file is part of the test suite of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:LGPL$
+** GNU Lesser General Public License Usage
+** 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 1.1, 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.
+**
+** Other Usage
+** Alternatively, this file may be used in accordance with the terms and
+** conditions contained in a signed written agreement between you and Nokia.
+**
+**
+**
+**
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include <qtest.h>
+#include <QtDeclarative/qdeclarativeengine.h>
+#include <QtDeclarative/qdeclarativecomponent.h>
+#include <QtDeclarative/qdeclarativeexpression.h>
+#include <QtDeclarative/qdeclarativescriptstring.h>
+
+#ifdef Q_OS_SYMBIAN
+// In Symbian OS test data is located in applications private dir
+#define SRCDIR "."
+#endif
+
+class tst_qdeclarativeexpression : public QObject
+{
+    Q_OBJECT
+public:
+    tst_qdeclarativeexpression() {}
+
+private slots:
+    void scriptString();
+};
+
+class TestObject : public QObject
+{
+    Q_OBJECT
+    Q_PROPERTY(QDeclarativeScriptString scriptString READ scriptString WRITE setScriptString)
+    Q_PROPERTY(QDeclarativeScriptString scriptStringError READ scriptStringError WRITE setScriptStringError)
+public:
+    TestObject(QObject *parent = 0) : QObject(parent) {}
+
+    QDeclarativeScriptString scriptString() const { return m_scriptString; }
+    void setScriptString(QDeclarativeScriptString scriptString) { m_scriptString = scriptString; }
+
+    QDeclarativeScriptString scriptStringError() const { return m_scriptStringError; }
+    void setScriptStringError(QDeclarativeScriptString scriptString) { m_scriptStringError = scriptString; }
+
+private:
+    QDeclarativeScriptString m_scriptString;
+    QDeclarativeScriptString m_scriptStringError;
+};
+
+QML_DECLARE_TYPE(TestObject)
+
+void tst_qdeclarativeexpression::scriptString()
+{
+    qmlRegisterType<TestObject>("Test", 1, 0, "TestObject");
+
+    QDeclarativeEngine engine;
+    QDeclarativeComponent c(&engine, QUrl::fromLocalFile(SRCDIR "/data/scriptString.qml"));
+    TestObject *testObj = qobject_cast<TestObject*>(c.create());
+    QVERIFY(testObj != 0);
+
+    QDeclarativeScriptString script = testObj->scriptString();
+    QCOMPARE(script.script(), QLatin1String("value1 + value2"));
+
+    QDeclarativeExpression expression(script);
+    QVariant value = expression.evaluate();
+    QCOMPARE(value.toInt(), 15);
+
+    QDeclarativeScriptString scriptError = testObj->scriptStringError();
+    QCOMPARE(scriptError.script(), QLatin1String("value3 * 5"));
+
+    //verify that the expression has the correct error location information
+    QDeclarativeExpression expressionError(scriptError);
+    QVariant valueError = expressionError.evaluate();
+    QVERIFY(!valueError.isValid());
+    QVERIFY(expressionError.hasError());
+    QDeclarativeError error = expressionError.error();
+    QCOMPARE(error.url(), c.url());
+    QCOMPARE(error.line(), 8);
+}
+
+QTEST_MAIN(tst_qdeclarativeexpression)
+
+#include "tst_qdeclarativeexpression.moc"