Support debugging and profiling for pure QJSEngines

The engines will register themselves with the debug server whenever
they are created without a private object. The assumption is that we
get the latest possible registration like this. They try to deregister
in all dtors, but they check if a different engine has done the same
first.

Change-Id: Ife7d7532d1de2e4a6ee21d9f7e673fcdfff2387b
Reviewed-by: Simon Hausmann <simon.hausmann@theqtcompany.com>

4 files changed, 33 insertions, 8 deletions

diff --git a/src/qml/jsapi/qjsengine.cpp b/src/qml/jsapi/qjsengine.cpp
index 5ccbccebad..80dce129c7 100644
--- a/src/qml/jsapi/qjsengine.cpp
+++ b/src/qml/jsapi/qjsengine.cpp
@@ -43,6 +43,7 @@
 #include "private/qv4script_p.h"
 #include "private/qv4runtime_p.h"
 #include <private/qqmlbuiltinfunctions_p.h>
+#include <private/qqmldebugconnector_p.h>
 
 #include <QtCore/qdatetime.h>
 #include <QtCore/qmetaobject.h>
@@ -251,6 +252,7 @@ QJSEngine::QJSEngine()
     : QObject(*new QJSEnginePrivate, 0)
     , d(new QV8Engine(this))
 {
+    QJSEnginePrivate::addToDebugServer(this);
 }
 
 /*!
@@ -264,6 +266,7 @@ QJSEngine::QJSEngine(QObject *parent)
     : QObject(*new QJSEnginePrivate, parent)
     , d(new QV8Engine(this))
 {
+    QJSEnginePrivate::addToDebugServer(this);
 }
 
 /*!
@@ -284,6 +287,7 @@ QJSEngine::QJSEngine(QJSEnginePrivate &dd, QObject *parent)
 */
 QJSEngine::~QJSEngine()
 {
+    QJSEnginePrivate::removeFromDebugServer(this);
     delete d;
 }
 
@@ -671,6 +675,26 @@ QJSEnginePrivate::~QJSEnginePrivate()
         (*iter)->release();
 }
 
+void QJSEnginePrivate::addToDebugServer(QJSEngine *q)
+{
+    if (QCoreApplication::instance()->thread() != q->thread())
+        return;
+
+    QQmlDebugConnector *server = QQmlDebugConnector::instance();
+    if (!server || server->hasEngine(q))
+        return;
+
+    server->open();
+    server->addEngine(q);
+}
+
+void QJSEnginePrivate::removeFromDebugServer(QJSEngine *q)
+{
+    QQmlDebugConnector *server = QQmlDebugConnector::instance();
+    if (server && server->hasEngine(q))
+        server->removeEngine(q);
+}
+
 QQmlPropertyCache *QJSEnginePrivate::createCache(const QMetaObject *mo)
 {
     if (!mo->superClass()) {
diff --git a/src/qml/jsapi/qjsengine_p.h b/src/qml/jsapi/qjsengine_p.h
index 8fdec08085..1fb8dc6fb2 100644
--- a/src/qml/jsapi/qjsengine_p.h
+++ b/src/qml/jsapi/qjsengine_p.h
@@ -70,6 +70,9 @@ public:
     QJSEnginePrivate() : mutex(QMutex::Recursive) {}
     ~QJSEnginePrivate();
 
+    static void addToDebugServer(QJSEngine *q);
+    static void removeFromDebugServer(QJSEngine *q);
+
     // Locker locks the QQmlEnginePrivate data structures for read and write, if necessary.
     // Currently, locking is only necessary if the threaded loader is running concurrently.  If it is
     // either idle, or is running with the main thread blocked, no locking is necessary.  This way
diff --git a/src/qml/qml/qqmlapplicationengine.cpp b/src/qml/qml/qqmlapplicationengine.cpp
index b2bf1939b0..4ab35e69e3 100644
--- a/src/qml/qml/qqmlapplicationengine.cpp
+++ b/src/qml/qml/qqmlapplicationengine.cpp
@@ -197,6 +197,7 @@ QQmlApplicationEngine::QQmlApplicationEngine(QObject *parent)
 {
     Q_D(QQmlApplicationEngine);
     d->init();
+    QJSEnginePrivate::addToDebugServer(this);
 }
 
 /*!
@@ -208,6 +209,7 @@ QQmlApplicationEngine::QQmlApplicationEngine(const QUrl &url, QObject *parent)
 {
     Q_D(QQmlApplicationEngine);
     d->init();
+    QJSEnginePrivate::addToDebugServer(this);
     load(url);
 }
 
@@ -224,6 +226,7 @@ QQmlApplicationEngine::QQmlApplicationEngine(const QString &filePath, QObject *p
 {
     Q_D(QQmlApplicationEngine);
     d->init();
+    QJSEnginePrivate::addToDebugServer(this);
     load(QUrl::fromLocalFile(filePath));
 }
 
@@ -233,6 +236,7 @@ QQmlApplicationEngine::QQmlApplicationEngine(const QString &filePath, QObject *p
 QQmlApplicationEngine::~QQmlApplicationEngine()
 {
     Q_D(QQmlApplicationEngine);
+    QJSEnginePrivate::removeFromDebugServer(this);
     d->cleanUp();//Instantiated root objects must be deleted before the engine
 }
 
diff --git a/src/qml/qml/qqmlengine.cpp b/src/qml/qml/qqmlengine.cpp
index 2d3d8aa03c..b3636d1fa6 100644
--- a/src/qml/qml/qqmlengine.cpp
+++ b/src/qml/qml/qqmlengine.cpp
@@ -868,11 +868,6 @@ void QQmlEnginePrivate::init()
     v8engine()->setEngine(q);
 
     rootContext = new QQmlContext(q,true);
-
-    if (QCoreApplication::instance()->thread() == q->thread() && QQmlDebugConnector::instance()) {
-        QQmlDebugConnector::instance()->open();
-        QQmlDebugConnector::instance()->addEngine(q);
-    }
 }
 
 QQuickWorkerScriptEngine *QQmlEnginePrivate::getWorkerScriptEngine()
@@ -924,6 +919,7 @@ QQmlEngine::QQmlEngine(QObject *parent)
 {
     Q_D(QQmlEngine);
     d->init();
+    QJSEnginePrivate::addToDebugServer(this);
 }
 
 /*!
@@ -948,9 +944,7 @@ QQmlEngine::QQmlEngine(QQmlEnginePrivate &dd, QObject *parent)
 QQmlEngine::~QQmlEngine()
 {
     Q_D(QQmlEngine);
-    QQmlDebugConnector *server = QQmlDebugConnector::instance();
-    if (server)
-        server->removeEngine(this);
+    QJSEnginePrivate::removeFromDebugServer(this);
 
     d->typeLoader.invalidate();