QmlProfiler: Make sure there's minimal overhead when not enabled

Do expensive operations directly in the constructor, guarded by
and if (enabled). Also assert if the methods where this isn't feasible
are called altough debugging hasn't been enabled.

Change-Id: Ieaa3c71730042a88af2270203ea747af42ba5c58
Reviewed-by: Aaron Kennedy <aaron.kennedy@nokia.com>

2 files changed, 24 insertions, 36 deletions

diff --git a/src/qml/debugger/qqmlprofilerservice_p.h b/src/qml/debugger/qqmlprofilerservice_p.h
index 94eed961ef..e9a58b41ec 100644
--- a/src/qml/debugger/qqmlprofilerservice_p.h
+++ b/src/qml/debugger/qqmlprofilerservice_p.h
@@ -54,12 +54,15 @@
 //
 
 #include <private/qqmldebugservice_p.h>
-#include <QtQml/qtqmlglobal.h>
+#include "qqmlexpression.h"
+
 #include <QtCore/qelapsedtimer.h>
+#include <QtCore/qmetaobject.h>
 #include <QtCore/qmutex.h>
 #include <QtCore/qvector.h>
 #include <QtCore/qstringbuilder.h>
 
+
 QT_BEGIN_HEADER
 
 QT_BEGIN_NAMESPACE
@@ -198,36 +201,26 @@ struct QQmlBindingProfiler {
 };
 
 struct QQmlHandlingSignalProfiler {
-    QQmlHandlingSignalProfiler()
+    QQmlHandlingSignalProfiler(const QMetaMethod &signal, QQmlExpression *expression)
     {
         enabled = QQmlProfilerService::instance
                 ? QQmlProfilerService::instance->profilingEnabled() : false;
         if (enabled) {
-            QQmlProfilerService::instance->startRange(
-                        QQmlProfilerService::HandlingSignal);
+            QQmlProfilerService *service = QQmlProfilerService::instance;
+            service->startRange(QQmlProfilerService::HandlingSignal);
+            service->rangeData(QQmlProfilerService::HandlingSignal,
+                               QLatin1String(signal.signature()) + QLatin1String(": ")
+                               + expression->expression());
+            service->rangeLocation(QQmlProfilerService::HandlingSignal,
+                                   expression->sourceFile(), expression->lineNumber(),
+                                   expression->columnNumber());
         }
     }
 
-    void setSignalInfo(const QString &name, const QString &expression)
-    {
-        if (enabled)
-            QQmlProfilerService::instance->rangeData(
-                        QQmlProfilerService::HandlingSignal,
-                        name % QLatin1String(": ") % expression);
-    }
-
-    void setLocation(const QString &file, int line, int column)
-    {
-        if (enabled)
-            QQmlProfilerService::instance->rangeLocation(
-                        QQmlProfilerService::HandlingSignal, file, line, column);
-    }
-
     ~QQmlHandlingSignalProfiler()
     {
         if (enabled)
-            QQmlProfilerService::instance->endRange(
-                        QQmlProfilerService::HandlingSignal);
+            QQmlProfilerService::instance->endRange(QQmlProfilerService::HandlingSignal);
     }
 
     bool enabled;
@@ -236,22 +229,23 @@ struct QQmlHandlingSignalProfiler {
 struct QQmlObjectCreatingProfiler {
     QQmlObjectCreatingProfiler()
     {
-        QQmlProfilerService *instance = QQmlProfilerService::instance;
-        enabled = instance ?
-                    instance->profilingEnabled() : false;
-        if (enabled)
-            instance->startRange(QQmlProfilerService::Creating);
+        enabled = QQmlProfilerService::instance
+                ? QQmlProfilerService::instance->profilingEnabled() : false;
+        if (enabled) {
+            QQmlProfilerService *service = QQmlProfilerService::instance;
+            service->startRange(QQmlProfilerService::Creating);
+        }
     }
 
     void setTypeName(const QString &typeName)
     {
-        if (enabled)
-            QQmlProfilerService::instance->rangeData(
-                        QQmlProfilerService::Creating, typeName);
+        Q_ASSERT_X(enabled, Q_FUNC_INFO, "method called although profiler is not enabled.");
+        QQmlProfilerService::instance->rangeData(QQmlProfilerService::Creating, typeName);
     }
 
     void setLocation(const QUrl &url, int line, int column)
     {
+        Q_ASSERT_X(enabled, Q_FUNC_INFO, "method called although profiler is not enabled.");
         if (enabled)
             QQmlProfilerService::instance->rangeLocation(
                         QQmlProfilerService::Creating, url, line, column);
diff --git a/src/qml/qml/qqmlboundsignal.cpp b/src/qml/qml/qqmlboundsignal.cpp
index ca6b13e7f8..3200aaea3a 100644
--- a/src/qml/qml/qqmlboundsignal.cpp
+++ b/src/qml/qml/qqmlboundsignal.cpp
@@ -174,13 +174,7 @@ int QQmlBoundSignal::qt_metacall(QMetaObject::Call c, int id, void **a)
         if (QQmlDebugService::isDebuggingEnabled())
             QV8DebugService::instance()->signalEmitted(QString::fromAscii(m_signal.signature()));
 
-        QQmlHandlingSignalProfiler prof;
-        if (prof.enabled) {
-            prof.setSignalInfo(QString::fromLatin1(m_signal.signature()),
-                               m_expression->expression());
-            prof.setLocation(m_expression->sourceFile(), m_expression->lineNumber(),
-                             m_expression->columnNumber());
-        }
+        QQmlHandlingSignalProfiler prof(m_signal, m_expression);
 
         m_isEvaluating = true;
         if (!m_paramsValid) {