Merge pull request #4204 from nyalldawson/cancel_without_blocking

Don't block when canceling canvas render jobs
qgis · Mar 2, 2017 · 1752d44 · 1752d44
2 parents e9dee40 + 6243f78
commit 1752d44
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Showing 13 changed files with 120 additions and 11 deletions.
diff --git a/python/core/qgsmaprenderercustompainterjob.sip b/python/core/qgsmaprenderercustompainterjob.sip
@@ -19,6 +19,7 @@ class QgsMapRendererCustomPainterJob : QgsMapRendererJob
 
     virtual void start();
     virtual void cancel();
+    virtual void cancelWithoutBlocking();
     virtual void waitForFinished();
     virtual bool isActive() const;
     virtual bool usedCachedLabels() const;

diff --git a/python/core/qgsmaprendererjob.sip b/python/core/qgsmaprendererjob.sip
@@ -18,6 +18,8 @@ class QgsMapRendererJob : QObject
     //! Does nothing if the rendering is not active.
     virtual void cancel() = 0;
 
+    virtual void cancelWithoutBlocking() = 0;
+
     //! Block until the job has finished.
     virtual void waitForFinished() = 0;
 

diff --git a/python/core/qgsmaprendererparalleljob.sip b/python/core/qgsmaprendererparalleljob.sip
@@ -18,6 +18,7 @@ class QgsMapRendererParallelJob : QgsMapRendererQImageJob
 
     virtual void start();
     virtual void cancel();
+    virtual void cancelWithoutBlocking();
     virtual void waitForFinished();
     virtual bool isActive() const;
     virtual bool usedCachedLabels() const;

diff --git a/python/core/qgsmaprenderersequentialjob.sip b/python/core/qgsmaprenderersequentialjob.sip
@@ -19,6 +19,7 @@ class QgsMapRendererSequentialJob : QgsMapRendererQImageJob
 
     virtual void start();
     virtual void cancel();
+    virtual void cancelWithoutBlocking();
     virtual void waitForFinished();
     virtual bool isActive() const;
     virtual bool usedCachedLabels() const;

diff --git a/src/core/qgsmaprenderercustompainterjob.cpp b/src/core/qgsmaprenderercustompainterjob.cpp
@@ -109,14 +109,7 @@ void QgsMapRendererCustomPainterJob::cancel()
 
   QgsDebugMsg( "QPAINTER canceling" );
   disconnect( &mFutureWatcher, &QFutureWatcher<void>::finished, this, &QgsMapRendererCustomPainterJob::futureFinished );
-
-  mLabelJob.context.setRenderingStopped( true );
-  for ( LayerRenderJobs::iterator it = mLayerJobs.begin(); it != mLayerJobs.end(); ++it )
-  {
-    it->context.setRenderingStopped( true );
-    if ( it->renderer && it->renderer->feedback() )
-      it->renderer->feedback()->cancel();
-  }
+  cancelWithoutBlocking();
 
   QTime t;
   t.start();
@@ -130,6 +123,23 @@ void QgsMapRendererCustomPainterJob::cancel()
   QgsDebugMsg( "QPAINTER canceled" );
 }
 
+void QgsMapRendererCustomPainterJob::cancelWithoutBlocking()
+{
+  if ( !isActive() )
+  {
+    QgsDebugMsg( "QPAINTER not running!" );
+    return;
+  }
+
+  mLabelJob.context.setRenderingStopped( true );
+  for ( LayerRenderJobs::iterator it = mLayerJobs.begin(); it != mLayerJobs.end(); ++it )
+  {
+    it->context.setRenderingStopped( true );
+    if ( it->renderer && it->renderer->feedback() )
+      it->renderer->feedback()->cancel();
+  }
+}
+
 void QgsMapRendererCustomPainterJob::waitForFinished()
 {
   if ( !isActive() )

diff --git a/src/core/qgsmaprenderercustompainterjob.h b/src/core/qgsmaprenderercustompainterjob.h
@@ -39,6 +39,7 @@ class CORE_EXPORT QgsMapRendererCustomPainterJob : public QgsMapRendererJob
 
     virtual void start() override;
     virtual void cancel() override;
+    virtual void cancelWithoutBlocking() override;
     virtual void waitForFinished() override;
     virtual bool isActive() const override;
     virtual bool usedCachedLabels() const override;

diff --git a/src/core/qgsmaprendererjob.h b/src/core/qgsmaprendererjob.h
@@ -121,6 +121,13 @@ class CORE_EXPORT QgsMapRendererJob : public QObject
     //! Does nothing if the rendering is not active.
     virtual void cancel() = 0;
 
+    /**
+     * Triggers cancelation of the rendering job without blocking. The render job will continue
+     * to operate until it is able to cancel, at which stage the finished() signal will be emitted.
+     * Does nothing if the rendering is not active.
+     */
+    virtual void cancelWithoutBlocking() = 0;
+
     //! Block until the job has finished.
     virtual void waitForFinished() = 0;
 
@@ -296,6 +303,7 @@ class CORE_EXPORT QgsMapRendererQImageJob : public QgsMapRendererJob
 
     //! Get a preview/resulting image
     virtual QImage renderedImage() = 0;
+
 };
 
 

diff --git a/src/core/qgsmaprendererparalleljob.cpp b/src/core/qgsmaprendererparalleljob.cpp
@@ -108,6 +108,28 @@ void QgsMapRendererParallelJob::cancel()
   Q_ASSERT( mStatus == Idle );
 }
 
+void QgsMapRendererParallelJob::cancelWithoutBlocking()
+{
+  if ( !isActive() )
+    return;
+
+  QgsDebugMsg( QString( "PARALLEL cancel at status %1" ).arg( mStatus ) );
+
+  mLabelJob.context.setRenderingStopped( true );
+  for ( LayerRenderJobs::iterator it = mLayerJobs.begin(); it != mLayerJobs.end(); ++it )
+  {
+    it->context.setRenderingStopped( true );
+    if ( it->renderer && it->renderer->feedback() )
+      it->renderer->feedback()->cancel();
+  }
+
+  if ( mStatus == RenderingLayers )
+  {
+    disconnect( &mFutureWatcher, &QFutureWatcher<void>::finished, this, &QgsMapRendererParallelJob::renderLayersFinished );
+    connect( &mFutureWatcher, &QFutureWatcher<void>::finished, this, &QgsMapRendererParallelJob::renderingFinished );
+  }
+}
+
 void QgsMapRendererParallelJob::waitForFinished()
 {
   if ( !isActive() )

diff --git a/src/core/qgsmaprendererparalleljob.h b/src/core/qgsmaprendererparalleljob.h
@@ -36,6 +36,7 @@ class CORE_EXPORT QgsMapRendererParallelJob : public QgsMapRendererQImageJob
 
     virtual void start() override;
     virtual void cancel() override;
+    virtual void cancelWithoutBlocking() override;
     virtual void waitForFinished() override;
     virtual bool isActive() const override;
 

diff --git a/src/core/qgsmaprenderersequentialjob.cpp b/src/core/qgsmaprenderersequentialjob.cpp
@@ -83,6 +83,15 @@ void QgsMapRendererSequentialJob::cancel()
   Q_ASSERT( !mInternalJob && !mPainter );
 }
 
+void QgsMapRendererSequentialJob::cancelWithoutBlocking()
+{
+  if ( !isActive() )
+    return;
+
+  QgsDebugMsg( "sequential - cancel internal" );
+  mInternalJob->cancelWithoutBlocking();
+}
+
 void QgsMapRendererSequentialJob::waitForFinished()
 {
   if ( !isActive() )

diff --git a/src/core/qgsmaprenderersequentialjob.h b/src/core/qgsmaprenderersequentialjob.h
@@ -38,6 +38,7 @@ class CORE_EXPORT QgsMapRendererSequentialJob : public QgsMapRendererQImageJob
 
     virtual void start() override;
     virtual void cancel() override;
+    virtual void cancelWithoutBlocking() override;
     virtual void waitForFinished() override;
     virtual bool isActive() const override;
 

diff --git a/src/gui/qgsmapcanvas.cpp b/src/gui/qgsmapcanvas.cpp
@@ -604,8 +604,10 @@ void QgsMapCanvas::stopRendering()
   {
     QgsDebugMsg( "CANVAS stop rendering!" );
     mJobCanceled = true;
-    mJob->cancel();
-    Q_ASSERT( !mJob ); // no need to delete here: already deleted in finished()
+    disconnect( mJob, &QgsMapRendererJob::finished, this, &QgsMapCanvas::rendererJobFinished );
+    connect( mJob, &QgsMapRendererQImageJob::finished, mJob, &QgsMapRendererQImageJob::deleteLater );
+    mJob->cancelWithoutBlocking();
+    mJob = nullptr;
   }
 }
 

diff --git a/tests/src/python/test_qgsmaprenderer.py b/tests/src/python/test_qgsmaprenderer.py
@@ -23,10 +23,14 @@
                        QgsProject,
                        QgsFeature,
                        QgsGeometry,
-                       QgsMapSettings)
+                       QgsMapSettings,
+                       QgsPoint)
 from qgis.testing import start_app, unittest
 from qgis.PyQt.QtCore import QSize, QThreadPool
 from qgis.PyQt.QtGui import QPainter, QImage
+from qgis.PyQt.QtTest import QSignalSpy
+from random import uniform
+
 
 app = start_app()
 
@@ -378,6 +382,51 @@ def checkLabeledLayerWithBlendModesCannotBeCached(self, job_type):
         self.assertFalse(cache.hasCacheImage('_labels_'))
         self.assertTrue(job.takeLabelingResults())
 
+    def checkCancel(self, job_type):
+        """test canceling a render job"""
+        layer = QgsVectorLayer("Point?field=fldtxt:string",
+                               "layer1", "memory")
+
+        # add a ton of random points
+        for i in range(2000):
+            x = uniform(5, 25)
+            y = uniform(25, 45)
+            g = QgsGeometry.fromPoint(QgsPoint(x, y))
+            f = QgsFeature()
+            f.setGeometry(g)
+            f.initAttributes(1)
+            layer.dataProvider().addFeatures([f])
+
+        settings = QgsMapSettings()
+        settings.setExtent(QgsRectangle(5, 25, 25, 45))
+        settings.setOutputSize(QSize(600, 400))
+        settings.setLayers([layer])
+
+        # first try non-blocking cancelWithoutBlocking() call
+        job = job_type(settings)
+        finished_spy = QSignalSpy(job.finished)
+        job.start()
+
+        # insta cancel!
+        job.cancelWithoutBlocking()
+        # should still be active immediately after
+        self.assertTrue(job.isActive())
+
+        while job.isActive():
+            app.processEvents()
+        self.assertEqual(len(finished_spy), 1)
+
+        # try blocking cancel() call
+        job = job_type(settings)
+        finished_spy = QSignalSpy(job.finished)
+        job.start()
+
+        # insta cancel!
+        job.cancel()
+        # should not be active anymore
+        self.assertFalse(job.isActive())
+        self.assertEqual(len(finished_spy), 1)
+
     def runRendererChecks(self, renderer):
         """ runs all checks on the specified renderer """
         self.checkRendererUseCachedLabels(renderer)
@@ -388,6 +437,7 @@ def runRendererChecks(self, renderer):
         self.checkAddingNewNonLabeledLayerKeepsLabelCache(renderer)
         self.checkRemovingNonLabeledLayerKeepsLabelCache(renderer)
         self.checkLabeledLayerWithBlendModesCannotBeCached(renderer)
+        self.checkCancel(renderer)
 
     def testParallelRenderer(self):
         """ run test suite on QgsMapRendererParallelJob"""