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authorSimon Hausmann <simon.hausmann@digia.com>2014-05-05 15:45:54 +0200
committerThe Qt Project <gerrit-noreply@qt-project.org>2014-05-09 17:27:07 +0200
commit073cde9d21f95a896ffff3abfcc9a9da89175e28 (patch)
treebe52c78b99e870489e7cb336a1110859a44605f6
parent0640dce6cd3200979a9b98d5bbae4526fc6dcec8 (diff)
Fix QJSEngine::evaluate using the wrong execution contextv5.3.0
In contrary to what the documentation says, QJSEngine in Qt 5.x executes in the context of the global object (QScriptIsolate always called enter on the QV8Engine's "root" context, thus making it current). The v4 implementation unfortunately did what the documentation said and used the current context, which is wrong in many ways. For example it completely breaks the optimization of stack allocated contexts, because when a C++ callback is called from within a JS function with a stack allocated context and that C++ code calls QJSEngine::evaluate and creates new closures, the stack context would become an outter context and cause crashes during GC. This patch restores the behavior of Qt 5.0/5.1 and fixes the documentation. Task-number: QTBUG-38530 Change-Id: Ie6481f02e676954cc94b188a1c87c88e7c56dafa Reviewed-by: Lars Knoll <lars.knoll@digia.com>
-rw-r--r--src/qml/jsapi/qjsengine.cpp13
-rw-r--r--tests/auto/qml/qjsengine/tst_qjsengine.cpp39
2 files changed, 48 insertions, 4 deletions
diff --git a/src/qml/jsapi/qjsengine.cpp b/src/qml/jsapi/qjsengine.cpp
index d05ada481a..9cb727dd63 100644
--- a/src/qml/jsapi/qjsengine.cpp
+++ b/src/qml/jsapi/qjsengine.cpp
@@ -235,7 +235,7 @@ void QJSEngine::collectGarbage()
Evaluates \a program, using \a lineNumber as the base line number,
and returns the result of the evaluation.
- The script code will be evaluated in the current context.
+ The script code will be evaluated in the context of the global object.
The evaluation of \a program can cause an exception in the
engine; in this case the return value will be the exception
@@ -261,8 +261,11 @@ void QJSEngine::collectGarbage()
*/
QJSValue QJSEngine::evaluate(const QString& program, const QString& fileName, int lineNumber)
{
- QV4::Scope scope(d->m_v4Engine);
- QV4::ExecutionContext *ctx = d->m_v4Engine->currentContext();
+ QV4::ExecutionEngine *v4 = d->m_v4Engine;
+ QV4::Scope scope(v4);
+ QV4::ExecutionContext *ctx = v4->currentContext();
+ if (ctx != v4->rootContext)
+ ctx = v4->pushGlobalContext();
QV4::ScopedValue result(scope);
QV4::Script script(ctx, program, fileName, lineNumber);
@@ -273,7 +276,9 @@ QJSValue QJSEngine::evaluate(const QString& program, const QString& fileName, in
result = script.run();
if (scope.engine->hasException)
result = ctx->catchException();
- return new QJSValuePrivate(d->m_v4Engine, result);
+ if (ctx != v4->rootContext)
+ v4->popContext();
+ return new QJSValuePrivate(v4, result);
}
/*!
diff --git a/tests/auto/qml/qjsengine/tst_qjsengine.cpp b/tests/auto/qml/qjsengine/tst_qjsengine.cpp
index b2723b02fd..17acb4fd32 100644
--- a/tests/auto/qml/qjsengine/tst_qjsengine.cpp
+++ b/tests/auto/qml/qjsengine/tst_qjsengine.cpp
@@ -157,6 +157,8 @@ private slots:
void dynamicProperties();
+ void scopeOfEvaluate();
+
signals:
void testSignal();
};
@@ -3011,6 +3013,43 @@ void tst_QJSEngine::dynamicProperties()
}
}
+class EvaluateWrapper : public QObject
+{
+ Q_OBJECT
+public:
+ EvaluateWrapper(QJSEngine *engine)
+ : engine(engine)
+ {}
+
+public slots:
+ QJSValue cppEvaluate(const QString &program)
+ {
+ return engine->evaluate(program);
+ }
+
+private:
+ QJSEngine *engine;
+};
+
+void tst_QJSEngine::scopeOfEvaluate()
+{
+ QJSEngine engine;
+ QJSValue wrapper = engine.newQObject(new EvaluateWrapper(&engine));
+
+ engine.evaluate("testVariable = 42");
+
+ QJSValue function = engine.evaluate("(function(evalWrapper){\n"
+ "var testVariable = 100; \n"
+ "try { \n"
+ " return evalWrapper.cppEvaluate(\"(function() { return testVariable; })\")\n"
+ " ()\n"
+ "} catch (e) {}\n"
+ "})");
+ QVERIFY(function.isCallable());
+ QJSValue result = function.call(QJSValueList() << wrapper);
+ QCOMPARE(result.toInt(), 42);
+}
+
QTEST_MAIN(tst_QJSEngine)
#include "tst_qjsengine.moc"