fix waitforfinished when task is not started

qgis · Nov 14, 2019 · 9887827 · 9887827
1 parent 0018190
commit 9887827
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Showing 3 changed files with 14 additions and 11 deletions.
diff --git a/src/core/qgstaskmanager.cpp b/src/core/qgstaskmanager.cpp
@@ -28,7 +28,9 @@
 QgsTask::QgsTask( const QString &name, Flags flags )
   : mFlags( flags )
   , mDescription( name )
+  , mNotStartedMutex( 1 )
 {
+  mNotStartedMutex.acquire();
 }
 
 QgsTask::~QgsTask()
@@ -41,6 +43,7 @@ QgsTask::~QgsTask()
     delete subTask.task;
   }
   mNotFinishedMutex.unlock();
+  mNotStartedMutex.release();
 }
 
 void QgsTask::setDescription( const QString &description )
@@ -56,6 +59,7 @@ qint64 QgsTask::elapsedTime() const
 void QgsTask::start()
 {
   mNotFinishedMutex.lock();
+  mNotStartedMutex.release();
   mStartCount++;
   Q_ASSERT( mStartCount == 1 );
 
@@ -152,6 +156,9 @@ QList<QgsMapLayer *> QgsTask::dependentLayers() const
 
 bool QgsTask::waitForFinished( int timeout )
 {
+  // We wait the task to be started
+  mNotStartedMutex.acquire();
+
   bool rv = true;
   if ( mOverallStatus == Complete || mOverallStatus == Terminated )
   {

diff --git a/src/core/qgstaskmanager.h b/src/core/qgstaskmanager.h
@@ -311,6 +311,12 @@ class CORE_EXPORT QgsTask : public QObject
      */
     QMutex mNotFinishedMutex;
 
+    /**
+     * This semaphore remains locked from task creation until the task actually start,
+     * it's used in waitForFinished to actually wait the task to be started.
+     */
+    QSemaphore mNotStartedMutex;
+
     //! Progress of this (parent) task alone
     double mProgress = 0.0;
     //! Overall progress of this task and all subtasks

diff --git a/tests/src/python/test_qgslayoutlegend.py b/tests/src/python/test_qgslayoutlegend.py
@@ -396,10 +396,6 @@ def testSymbolExpressions(self):
 
         counterTask = point_layer.countSymbolFeatures()
         counterTask.waitForFinished()
-        TM = QgsApplication.taskManager()
-        actask = TM.activeTasks()
-        print(TM.tasks(), actask)
-        count = actask[0]
         legend.model().refreshLayerLegend(legendlayer)
         legendnodes = legend.model().layerLegendNodes(legendlayer)
         legendnodes[0].setUserLabel('[% @symbol_id %]')
@@ -408,7 +404,6 @@ def testSymbolExpressions(self):
         label1 = legendnodes[0].evaluateLabel()
         label2 = legendnodes[1].evaluateLabel()
         label3 = legendnodes[2].evaluateLabel()
-        count.waitForFinished()
         self.assertEqual(label1, '0')
         #self.assertEqual(label2, '5')
         #self.assertEqual(label3, '12')
@@ -463,7 +458,7 @@ def testSymbolExpressionRender(self):
         group = legend.model().rootGroup().addGroup("Group [% 1 + 5 %] [% @layout_name %]")
         layer_tree_layer = group.addLayer(point_layer)
         counterTask = point_layer.countSymbolFeatures()
-        counterTask.waitForFinished() # does this even work?
+        counterTask.waitForFinished()
         layer_tree_layer.setCustomProperty("legend/title-label", 'bbbb [% 1+2 %] xx [% @layout_name %] [% @layer_name %]')
         QgsMapLayerLegendUtils.setLegendNodeUserLabel(layer_tree_layer, 0, 'xxxx')
         legend.model().refreshLayerLegend(layer_tree_layer)
@@ -475,11 +470,6 @@ def testSymbolExpressionRender(self):
         legend.setLinkedMap(map)
         legend.updateLegend()
         print(layer_tree_layer.labelExpression())
-        TM = QgsApplication.taskManager()
-        actask = TM.activeTasks()
-        print(TM.tasks(), actask)
-        count = actask[0]
-        count.waitForFinished()
         map.setExtent(QgsRectangle(-102.51, 41.16, -102.36, 41.30))
         checker = QgsLayoutChecker(
             'composer_legend_symbol_expression', layout)