Add QgsThreadingUtils::runOnMainThread

qgis · Sep 11, 2018 · 6ab1aa7 · 6ab1aa7
1 parent e192e18
commit 6ab1aa7
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Showing 5 changed files with 77 additions and 48 deletions.
diff --git a/src/analysis/vector/geometry_checker/qgsgeometrycheck.cpp b/src/analysis/vector/geometry_checker/qgsgeometrycheck.cpp
@@ -19,21 +19,7 @@
 #include "qgsfeaturepool.h"
 #include "qgsvectorlayer.h"
 #include "qgsreadwritelocker.h"
-
-template <typename Func>
-void runOnMainThread( const Func &func )
-{
-#if QT_VERSION >= QT_VERSION_CHECK( 5, 10, 0 )
-  // Make sure we only deal with the vector layer on the main thread where it lives.
-  // Anything else risks a crash.
-  if ( QThread::currentThread() == qApp->thread() )
-    func();
-  else
-    QMetaObject::invokeMethod( qApp, func, Qt::BlockingQueuedConnection );
-#else
-  func();
-#endif
-}
+#include "qgsthreadingutils.h"
 
 QgsGeometryCheckerContext::QgsGeometryCheckerContext( int _precision, const QgsCoordinateReferenceSystem &_mapCrs, const QMap<QString, QgsFeaturePool *> &_featurePools, const QgsCoordinateTransformContext &transformContext )
   : tolerance( std::pow( 10, -_precision ) )
@@ -50,7 +36,7 @@ const QgsCoordinateTransform &QgsGeometryCheckerContext::layerTransform( const Q
   if ( !mTransformCache.contains( layer ) )
   {
     QgsCoordinateTransform transform;
-    runOnMainThread( [this, &transform, layer]()
+    QgsThreadingUtils::runOnMainThread( [this, &transform, layer]()
     {
       QgsVectorLayer *lyr = layer.data();
       if ( lyr )
@@ -70,7 +56,7 @@ double QgsGeometryCheckerContext::layerScaleFactor( const QPointer<QgsVectorLaye
   if ( !mScaleFactorCache.contains( layer ) )
   {
     double scaleFactor = 1.0;
-    runOnMainThread( [this, layer, &scaleFactor]()
+    QgsThreadingUtils::runOnMainThread( [this, layer, &scaleFactor]()
     {
       QgsVectorLayer *lyr = layer.data();
       if ( lyr )

diff --git a/src/analysis/vector/geometry_checker/qgsvectordataproviderfeaturepool.cpp b/src/analysis/vector/geometry_checker/qgsvectordataproviderfeaturepool.cpp
@@ -14,24 +14,10 @@ email                : matthias@opengis.ch
  ***************************************************************************/
 
 #include "qgsvectordataproviderfeaturepool.h"
+#include "qgsthreadingutils.h"
 
 #include "qgsfeaturerequest.h"
 
-template <typename Func>
-void runOnMainThread( const Func &func )
-{
-#if QT_VERSION >= QT_VERSION_CHECK( 5, 10, 0 )
-  // Make sure we only deal with the vector layer on the main thread where it lives.
-  // Anything else risks a crash.
-  if ( QThread::currentThread() == qApp->thread() )
-    func();
-  else
-    QMetaObject::invokeMethod( qApp, func, Qt::BlockingQueuedConnection );
-#else
-  func();
-#endif
-}
-
 QgsVectorDataProviderFeaturePool::QgsVectorDataProviderFeaturePool( QgsVectorLayer *layer, bool selectedOnly )
   : QgsFeaturePool( layer )
   , mSelectedOnly( selectedOnly )
@@ -77,15 +63,15 @@ bool QgsVectorDataProviderFeaturePool::addFeature( QgsFeature &feature, Flags fl
       res = lyr->dataProvider()->addFeatures( features );
   };
 
-  runOnMainThread( addFeatureSynchronized );
+  QgsThreadingUtils::runOnMainThread( addFeatureSynchronized );
 
   if ( !res )
     return false;
 
   feature.setId( features.front().id() );
   if ( mSelectedOnly )
   {
-    runOnMainThread( [ this, feature ]()
+    QgsThreadingUtils::runOnMainThread( [ this, feature ]()
     {
       QgsVectorLayer *lyr = layer();
       if ( lyr )
@@ -115,14 +101,14 @@ bool QgsVectorDataProviderFeaturePool::addFeatures( QgsFeatureList &features, Qg
       res = lyr->dataProvider()->addFeatures( features );
   };
 
-  runOnMainThread( addFeatureSynchronized );
+  QgsThreadingUtils::runOnMainThread( addFeatureSynchronized );
 
   if ( !res )
     return false;
 
   if ( mSelectedOnly )
   {
-    runOnMainThread( [ this, features ]()
+    QgsThreadingUtils::runOnMainThread( [ this, features ]()
     {
       QgsVectorLayer *lyr = layer();
       if ( lyr )
@@ -156,7 +142,7 @@ void QgsVectorDataProviderFeaturePool::updateFeature( QgsFeature &feature )
   }
   changedAttributesMap.insert( feature.id(), attribMap );
 
-  runOnMainThread( [this, geometryMap, changedAttributesMap]()
+  QgsThreadingUtils::runOnMainThread( [this, geometryMap, changedAttributesMap]()
   {
     QgsVectorLayer *lyr = layer();
     if ( lyr )
@@ -172,7 +158,7 @@ void QgsVectorDataProviderFeaturePool::updateFeature( QgsFeature &feature )
 void QgsVectorDataProviderFeaturePool::deleteFeature( QgsFeatureId fid )
 {
   removeFeature( fid );
-  runOnMainThread( [this, fid]()
+  QgsThreadingUtils::runOnMainThread( [this, fid]()
   {
     QgsVectorLayer *lyr = layer();
     if ( lyr )

diff --git a/src/core/CMakeLists.txt b/src/core/CMakeLists.txt
@@ -946,6 +946,7 @@ SET(QGIS_CORE_HDRS
   qgstextlabelfeature.h
   qgstextrenderer.h
   qgstextrenderer_p.h
+  qgsthreadingutils.h
   qgstracer.h
   qgstranslationcontext.h
 

diff --git a/src/core/qgsthreadingutils.h b/src/core/qgsthreadingutils.h
@@ -0,0 +1,64 @@
+/***************************************************************************
+               qgsthreadingutils.h
+                     --------------------------------------
+               Date                 : 11.9.2018
+               Copyright            : (C) 2018 by Matthias Kuhn
+               email                : matthias@opengis.ch
+ ***************************************************************************
+ *                                                                         *
+ *   This program is free software; you can redistribute it and/or modify  *
+ *   it under the terms of the GNU General Public License as published by  *
+ *   the Free Software Foundation; either version 2 of the License, or     *
+ *   (at your option) any later version.                                   *
+ *                                                                         *
+ ***************************************************************************/
+
+#ifndef QGSTHREADINGUTILS_H
+#define QGSTHREADINGUTILS_H
+
+#define SIP_NO_FILE
+
+#include "qgis_core.h"
+
+#include <QThread>
+
+/**
+ * \ingroup core
+ * Provides threading utilities for QGIS.
+ */
+class CORE_EXPORT QgsThreadingUtils
+{
+  public:
+
+    /**
+     * Guarantees that \a func is executed on the main thread. If this is called
+     * from another thread, the other thread will be blocked until the function
+     * has been executed.
+     * This is useful to quickly access information from objects that live on the
+     * main thread and copying this information into worker threads. Avoid running
+     * expensive code inside \a func.
+     *
+     * \note Only works with Qt >= 5.10, earlier versions will execute the code
+     *       in the worker thread.
+     *
+     * \since QGIS 3.4
+     */
+    template <typename Func>
+    static void runOnMainThread( const Func &func )
+    {
+#if QT_VERSION >= QT_VERSION_CHECK( 5, 10, 0 )
+      // Make sure we only deal with the vector layer on the main thread where it lives.
+      // Anything else risks a crash.
+      if ( QThread::currentThread() == qApp->thread() )
+        func();
+      else
+        QMetaObject::invokeMethod( qApp, func, Qt::BlockingQueuedConnection );
+#else
+      func();
+#endif
+    }
+
+};
+
+
+#endif
diff --git a/src/core/qgsvectorlayerutils.cpp b/src/core/qgsvectorlayerutils.cpp
@@ -24,6 +24,7 @@
 #include "qgsrelationmanager.h"
 #include "qgsfeedback.h"
 #include "qgsvectorlayer.h"
+#include "qgsthreadingutils.h"
 
 QgsFeatureIterator QgsVectorLayerUtils::getValuesIterator( const QgsVectorLayer *layer, const QString &fieldOrExpression, bool &ok, bool selectedOnly )
 {
@@ -516,16 +517,7 @@ std::unique_ptr<QgsVectorLayerFeatureSource> QgsVectorLayerUtils::getFeatureSour
     }
   };
 
-#if QT_VERSION >= QT_VERSION_CHECK( 5, 10, 0 )
-  // Make sure we only deal with the vector layer on the main thread where it lives.
-  // Anything else risks a crash.
-  if ( QThread::currentThread() == qApp->thread() )
-    getFeatureSource();
-  else
-    QMetaObject::invokeMethod( qApp, getFeatureSource, Qt::BlockingQueuedConnection );
-#else
-  getFeatureSource();
-#endif
+  QgsThreadingUtils::runOnMainThread( getFeatureSource );
 
   return featureSource;
 }