Avoid calling out to public API in the QtScript implementation

There's no reason to construct QScriptValues when JSC::JSValues
can be operated on directly. A benchmark showed that ~10% of the
time for reading a QObject property from a script was spent just
creating and destroying QScriptValue temporaries. It's time to
finally get rid of this potential bottleneck, not just in the
QObject integration but everywhere.

This change refactors the code so that all internal operations
are performed on JSC::JSValue (most importantly, conversion
from/to Qt types), and the public API functions are just thin
wrappers around these. E.g. instead of doing

enginePrivate->scriptValueFromJSCValue(jsValue).toQObject()

the implementation now does

QScriptEnginePrivate::toQObject(jsValue)

Other operations are delegated to the engine implementation
in similar style.

Task-number: QTBUG-8304
Reviewed-by: Jedrzej Nowacki

1 files changed, 17 insertions, 89 deletions

diff --git a/src/script/api/qscriptvalue.cpp b/src/script/api/qscriptvalue.cpp
index a7d9f79..7f1fdaa 100644
--- a/src/script/api/qscriptvalue.cpp
+++ b/src/script/api/qscriptvalue.cpp
@@ -42,14 +42,6 @@
 #include <QtCore/qvarlengtharray.h>
 #include <QtCore/qnumeric.h>
 
-#include "utils/qscriptdate_p.h"
-#include "bridge/qscriptobject_p.h"
-#include "bridge/qscriptclassobject_p.h"
-#include "bridge/qscriptvariant_p.h"
-#include "bridge/qscriptqobject_p.h"
-#include "bridge/qscriptdeclarativeclass_p.h"
-#include "bridge/qscriptdeclarativeobject_p.h"
-
 /*!
   \since 4.3
   \class QScriptValue
@@ -176,22 +168,6 @@
 
 QT_BEGIN_NAMESPACE
 
-QVariant &QScriptValuePrivate::variantValue() const
-{
-    Q_ASSERT(jscValue.inherits(&QScriptObject::info));
-    QScriptObjectDelegate *delegate = static_cast<QScriptObject*>(JSC::asObject(jscValue))->delegate();
-    Q_ASSERT(delegate && (delegate->type() == QScriptObjectDelegate::Variant));
-    return static_cast<QScript::QVariantDelegate*>(delegate)->value();
-}
-
-void QScriptValuePrivate::setVariantValue(const QVariant &value)
-{
-    Q_ASSERT(jscValue.inherits(&QScriptObject::info));
-    QScriptObjectDelegate *delegate = static_cast<QScriptObject*>(JSC::asObject(jscValue))->delegate();
-    Q_ASSERT(delegate && (delegate->type() == QScriptObjectDelegate::Variant));
-    static_cast<QScript::QVariantDelegate*>(delegate)->setValue(value);
-}
-
 void QScriptValuePrivate::detachFromEngine()
 {
     if (isJSC())
@@ -1205,40 +1181,10 @@ QVariant QScriptValue::toVariant() const
     if (!d)
         return QVariant();
     switch (d->type) {
-    case QScriptValuePrivate::JavaScriptCore:
-        if (isObject()) {
-            if (isVariant())
-                return d->variantValue();
-#ifndef QT_NO_QOBJECT
-            else if (isQObject())
-                return qVariantFromValue(toQObject());
-#endif
-            else if (isDate())
-                return QVariant(toDateTime());
-#ifndef QT_NO_REGEXP
-            else if (isRegExp())
-                return QVariant(toRegExp());
-#endif
-            else if (isArray())
-                return QScriptEnginePrivate::variantListFromArray(*this);
-            else if (QScriptDeclarativeClass *dc = QScriptDeclarativeClass::scriptClass(*this))
-                return dc->toVariant(QScriptDeclarativeClass::object(*this));
-            // try to convert to primitive
-            JSC::ExecState *exec = d->engine->currentFrame;
-            JSC::JSValue savedException;
-            QScriptEnginePrivate::saveException(exec, &savedException);
-            JSC::JSValue prim = d->jscValue.toPrimitive(exec);
-            QScriptEnginePrivate::restoreException(exec, savedException);
-            if (!prim.isObject())
-                return d->engine->scriptValueFromJSCValue(prim).toVariant();
-        } else if (isNumber()) {
-            return QVariant(toNumber());
-        } else if (isString()) {
-            return QVariant(toString());
-        } else if (isBool()) {
-            return QVariant(toBool());
-        }
-        return QVariant();
+    case QScriptValuePrivate::JavaScriptCore: {
+        JSC::ExecState *exec = d->engine ? d->engine->currentFrame : 0;
+        return QScriptEnginePrivate::toVariant(exec, d->jscValue);
+    }
     case QScriptValuePrivate::Number:
         return QVariant(d->numberValue);
     case QScriptValuePrivate::String:
@@ -1286,13 +1232,9 @@ QDateTime QScriptValue::toDateTime() const
 QRegExp QScriptValue::toRegExp() const
 {
     Q_D(const QScriptValue);
-    if (!isRegExp())
-        return QRegExp();
-    QString pattern = property(QLatin1String("source"), QScriptValue::ResolvePrototype).toString();
-    Qt::CaseSensitivity kase = Qt::CaseSensitive;
-    if (property(QLatin1String("ignoreCase"), QScriptValue::ResolvePrototype).toBool())
-        kase = Qt::CaseInsensitive;
-    return QRegExp(pattern, kase, QRegExp::RegExp2);
+    if (!d || !d->engine)
+         return QRegExp();
+    return QScriptEnginePrivate::toRegExp(d->engine->currentFrame, d->jscValue);
 }
 #endif // QT_NO_REGEXP
 
@@ -1309,19 +1251,9 @@ QRegExp QScriptValue::toRegExp() const
 QObject *QScriptValue::toQObject() const
 {
     Q_D(const QScriptValue);
-    if (isQObject()) {
-        QScriptObject *object = static_cast<QScriptObject*>(JSC::asObject(d->jscValue));
-        QScriptObjectDelegate *delegate = object->delegate();
-        if (delegate->type() == QScriptObjectDelegate::DeclarativeClassObject)
-            return static_cast<QScript::DeclarativeObjectDelegate*>(delegate)->scriptClass()->toQObject(QScriptDeclarativeClass::object(*this));
-        return static_cast<QScript::QObjectDelegate*>(delegate)->value();
-    } else if (isVariant()) {
-        QVariant var = toVariant();
-        int type = var.userType();
-        if ((type == QMetaType::QObjectStar) || (type == QMetaType::QWidgetStar))
-            return *reinterpret_cast<QObject* const *>(var.constData());
-    }
-    return 0;
+    if (!d || !d->engine)
+        return 0;
+    return QScriptEnginePrivate::toQObject(d->engine->currentFrame, d->jscValue);
 }
 
 /*!
@@ -1333,9 +1265,9 @@ QObject *QScriptValue::toQObject() const
 const QMetaObject *QScriptValue::toQMetaObject() const
 {
     Q_D(const QScriptValue);
-    if (isQMetaObject())
-        return static_cast<QScript::QMetaObjectWrapperObject*>(JSC::asObject(d->jscValue))->value();
-    return 0;
+    if (!d || !d->engine)
+        return 0;
+    return QScriptEnginePrivate::toQMetaObject(d->engine->currentFrame, d->jscValue);
 }
 
 /*!
@@ -1971,13 +1903,9 @@ bool QScriptValue::isVariant() const
 bool QScriptValue::isQObject() const
 {
     Q_D(const QScriptValue);
-    if (!d || !d->isJSC() || !d->jscValue.inherits(&QScriptObject::info))
+    if (!d || !d->isJSC())
         return false;
-    QScriptObject *object = static_cast<QScriptObject*>(JSC::asObject(d->jscValue));
-    QScriptObjectDelegate *delegate = object->delegate();
-    return (delegate && (delegate->type() == QScriptObjectDelegate::QtObject ||
-                         (delegate->type() == QScriptObjectDelegate::DeclarativeClassObject &&
-                          static_cast<QScript::DeclarativeObjectDelegate*>(delegate)->scriptClass()->isQObject())));
+    return QScriptEnginePrivate::isQObject(d->jscValue);
 }
 
 /*!
@@ -1989,9 +1917,9 @@ bool QScriptValue::isQObject() const
 bool QScriptValue::isQMetaObject() const
 {
     Q_D(const QScriptValue);
-    if (!d || !d->isObject())
+    if (!d || !d->isJSC())
         return false;
-    return JSC::asObject(d->jscValue)->inherits(&QScript::QMetaObjectWrapperObject::info);
+    return QScriptEnginePrivate::isQMetaObject(d->jscValue);
 }
 
 /*!