Periodically flush profiling data to client.

This reduces memory usage as the data can be deleted once it is sent.
It also reduces the time it takes to transmit the data when profiling
is stopped. It does incur a runtime cost as the sending now takes place
while the application is running. The decision to periodically flush or
not is left to the client, who can specify a flush interval when
starting profiling.

Usage of the flushing feature also relaxes the guarantees regarding the
sorting of events before they are sent. Events with higher timestamps
are now allowed to arrive before events with lower timestamps. Any
clients implementing the flushing need to take this into account. This
will eventually allow us to do away with the server-side ordering
altogether.

Task-number: QTBUG-39756
Change-Id: Idaf4931dc17f224c2bd492078b99e88b1405234e
Reviewed-by: Simon Hausmann <simon.hausmann@theqtcompany.com>

1 files changed, 8 insertions, 8 deletions

diff --git a/src/quick/util/qquickprofiler.cpp b/src/quick/util/qquickprofiler.cpp
index d9132a9cb..7bd32f07e 100644
--- a/src/quick/util/qquickprofiler.cpp
+++ b/src/quick/util/qquickprofiler.cpp
@@ -113,10 +113,15 @@ void QQuickProfilerData::toByteArrays(QList<QByteArray> &messages) const
 qint64 QQuickProfiler::sendMessages(qint64 until, QList<QByteArray> &messages)
 {
     QMutexLocker lock(&m_dataMutex);
-    while (next < m_data.size() && m_data[next].time <= until) {
-        m_data[next++].toByteArrays(messages);
+    while (next < m_data.size()) {
+        if (m_data[next].time <= until)
+            m_data[next++].toByteArrays(messages);
+        else
+            return m_data[next].time;
     }
-    return next < m_data.size() ? m_data[next].time : -1;
+    m_data.clear();
+    next = 0;
+    return -1;
 }
 
 void QQuickProfiler::initialize()
@@ -196,17 +201,12 @@ void QQuickProfiler::stopProfilingImpl()
     {
         QMutexLocker lock(&m_dataMutex);
         featuresEnabled = 0;
-        next = 0;
     }
     service->dataReady(this);
 }
 
 void QQuickProfiler::reportDataImpl()
 {
-    {
-        QMutexLocker lock(&m_dataMutex);
-        next = 0;
-    }
     service->dataReady(this);
 }