QDeclarativeTrace patch for a custom trace instance

Needed for the BB10 Cascades profiling. There are more reasons for
introducing this patch:

1) Cascades do not use QtGui library for QML rendering. It has its own
paint engine with client-server architecture. Profiler traces are sent
asynchronously from non Qt renderer thread to the Qt client.
The QPerformanceTimer has to be patched too, cause we need to know time
difference between tracing zero time and some time in past,
see: qint64 QPerformanceTimer::elapsed(qint64 to_monotonic_time_ns) const

2) Since we need more sophisticated trace engine in cascades, this patch
allows explicitly assign custom class derived from QDeclaraqtiveDebugtrace
to the trace framework.
If no custom instance is assigned, the default QDeclarativeDebugTrace
instance is created implicitly on first trace request.
Using custom trace instance which is not part of Qt
(it is part of libbbcascades) allows us to implement all Cascades trace
special needs in libbbcascades and not to carry Qt with the platform
specific code.

3) The NO_CUSTOM_DECLARATIVE_DEBUG_TRACE_INSTANCE macro is introduced to
allow custom trace engine only on the bleckberry platform,
see declarative.pro.
If this macro is defined Qt compiles from its original code.

4) Possibility of custom QDeclaraqtiveDebugTrace instance might be usable
for other projects which needs to extends somehow default Qt trace
functionality.

5) Patch is not intended to be applied to Qt Quick 2, since declarative
debugging infrastructure is changed there.

Change-Id: I199211c1de66e930e252e8c033503d7f4940565f
Reviewed-by: Kai Koehne <kai.koehne@digia.com>
Reviewed-by: Christiaan Janssen <christiaan.janssen@digia.com>

1 files changed, 28 insertions, 0 deletions

diff --git a/src/declarative/qml/qperformancetimer.cpp b/src/declarative/qml/qperformancetimer.cpp
index b7c2f47c..9e2e0734 100644
--- a/src/declarative/qml/qperformancetimer.cpp
+++ b/src/declarative/qml/qperformancetimer.cpp
@@ -80,6 +80,13 @@ qint64 QPerformanceTimer::elapsed() const
     return absoluteToNSecs(cpu_time - t1);
 }
 
+// return number of nsecs elapsed from timer start time till absoluteMonotonicTimeNs
+qint64 QPerformanceTimer::elapsedToAbsoluteTime(qint64 absoluteMonotonicTimeNs) const
+{
+    uint64_t cpu_time = absoluteMonotonicTimeNs;
+    return absoluteToNSecs(cpu_time - t1);
+}
+
 ////////////////////////////// Unix //////////////////////////////
 #elif defined(Q_OS_UNIX)
 
@@ -154,6 +161,16 @@ qint64 QPerformanceTimer::elapsed() const
     return sec * Q_INT64_C(1000000000) + frac;
 }
 
+qint64 QPerformanceTimer::elapsedToAbsoluteTime(qint64 absoluteMonotonicTimeNs) const
+{
+    qint64 sec = absoluteMonotonicTimeNs / Q_INT64_C(1000000000);
+    qint64 frac = absoluteMonotonicTimeNs % Q_INT64_C(1000000000);
+    sec = sec - t1;
+    frac = frac - t2;
+
+    return sec * Q_INT64_C(1000000000) + frac;
+}
+
 ////////////////////////////// Windows //////////////////////////////
 #elif defined(Q_OS_WIN)
 
@@ -179,6 +196,11 @@ qint64 QPerformanceTimer::elapsed() const
     return getTimeFromTick(li.QuadPart - t1);
 }
 
+qint64 QPerformanceTimer::elapsedToAbsoluteTime(qint64 absoluteMonotonicTimeNs) const
+{
+    return absoluteMonotonicTimeNs - t1;
+}
+
 ////////////////////////////// Default //////////////////////////////
 #else
 
@@ -192,6 +214,12 @@ qint64 QPerformanceTimer::elapsed() const
     return 0;
 }
 
+qint64 QPerformanceTimer::elapsedToAbsoluteTime(qint64 absoluteMonotonicTimeNs) const
+{
+    Q_UNUSED(absoluteMonotonicTimeNs);
+    return 0;
+}
+
 #endif
 
 QT_END_NAMESPACE