Cleanup QgsTask API for dependent layers

qgis · Dec 6, 2016 · adff069 · adff069
1 parent a52a1e9
commit adff069
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Showing 4 changed files with 79 additions and 23 deletions.
diff --git a/python/core/qgstaskmanager.sip b/python/core/qgstaskmanager.sip
@@ -133,6 +133,20 @@ class QgsTask : QObject
     void addSubTask( QgsTask* subTask /Transfer/, const QgsTaskList& dependencies = QgsTaskList(),
                      SubTaskDependency subTaskDependency = SubTaskIndependent );
 
+    /**
+     * Sets a list of layer IDs on which the task depends. The task will automatically
+     * be cancelled if any of these layers are about to be removed.
+     * @see dependentLayerIds()
+     */
+    void setDependentLayers( const QStringList& dependentLayerIds );
+
+    /**
+     * Returns the list of layer IDs on which the task depends. The task will automatically
+     * be cancelled if any of these layers are about to be removed.
+     * @see setDependentLayers()
+     */
+    QStringList dependentLayerIds() const;
+
   signals:
 
     /**
@@ -310,22 +324,20 @@ class QgsTaskManager : QObject
     //! @note not available in Python bindings
     //QSet< long > dependencies( long taskId ) const;
 
-    /** Sets a list of layers on which as task is dependent. The task will automatically
-     * be cancelled if any of these layers are above to be removed.
-     * @param taskId task ID
-     * @param layerIds list of layer IDs
-     * @see dependentLayers()
-     */
-    void setDependentLayers( long taskId, const QStringList& layerIds );
-
     /** Returns a list of layers on which as task is dependent. The task will automatically
      * be cancelled if any of these layers are above to be removed.
      * @param taskId task ID
      * @returns list of layer IDs
-     * @see setDependentLayers()
+     * @see tasksDependentOnLayer()
      */
     QStringList dependentLayers( long taskId ) const;
 
+    /**
+     * Returns a list of tasks which depend on a layer.
+     * @see dependentLayers()
+     */
+    QList< QgsTask* > tasksDependentOnLayer( const QString& layerId ) const;
+
     /** Returns a list of the active (queued or running) tasks.
      * @see countActiveTasks()
      */

diff --git a/src/core/qgstaskmanager.cpp b/src/core/qgstaskmanager.cpp
@@ -136,6 +136,11 @@ void QgsTask::addSubTask( QgsTask* subTask, const QgsTaskList& dependencies,
   connect( subTask, &QgsTask::statusChanged, this, &QgsTask::subTaskStatusChanged );
 }
 
+void QgsTask::setDependentLayers( const QStringList& dependentLayerIds )
+{
+  mDependentLayerIds = dependentLayerIds;
+}
+
 void QgsTask::subTaskStatusChanged( int status )
 {
   QgsTask* subTask = qobject_cast< QgsTask* >( sender() );
@@ -371,6 +376,8 @@ long QgsTaskManager::addTaskPrivate( QgsTask* task, QgsTaskList dependencies, bo
   {
     mParentTasks << task;
   }
+  if ( !task->dependentLayerIds().isEmpty() )
+    mLayerDependencies.insert( taskId, task->dependentLayerIds() );
   mTaskMutex->unlock();
 
   connect( task, &QgsTask::statusChanged, this, &QgsTaskManager::taskStatusChanged );
@@ -539,16 +546,27 @@ bool QgsTaskManager::hasCircularDependencies( long taskId ) const
   return !resolveDependencies( taskId, taskId, d );
 }
 
-void QgsTaskManager::setDependentLayers( long taskId, const QStringList& layerIds )
+QStringList QgsTaskManager::dependentLayers( long taskId ) const
 {
   QMutexLocker ml( mTaskMutex );
-  mLayerDependencies.insert( taskId, layerIds );
+  return mLayerDependencies.value( taskId, QStringList() );
 }
 
-QStringList QgsTaskManager::dependentLayers( long taskId ) const
+QList<QgsTask*> QgsTaskManager::tasksDependentOnLayer( const QString& layerId ) const
 {
   QMutexLocker ml( mTaskMutex );
-  return mLayerDependencies.value( taskId, QStringList() );
+  QList< QgsTask* > tasks;
+  QMap< long, QStringList >::const_iterator layerIt = mLayerDependencies.constBegin();
+  for ( ; layerIt != mLayerDependencies.constEnd(); ++layerIt )
+  {
+    if ( layerIt.value().contains( layerId ) )
+    {
+      QgsTask* layerTask = task( layerIt.key() );
+      if ( layerTask )
+        tasks << layerTask;
+    }
+  }
+  return tasks;
 }
 
 QList<QgsTask*> QgsTaskManager::activeTasks() const

diff --git a/src/core/qgstaskmanager.h b/src/core/qgstaskmanager.h
@@ -165,6 +165,20 @@ class CORE_EXPORT QgsTask : public QObject
     void addSubTask( QgsTask* subTask, const QgsTaskList& dependencies = QgsTaskList(),
                      SubTaskDependency subTaskDependency = SubTaskIndependent );
 
+    /**
+     * Sets a list of layer IDs on which the task depends. The task will automatically
+     * be cancelled if any of these layers are about to be removed.
+     * @see dependentLayerIds()
+     */
+    void setDependentLayers( const QStringList& dependentLayerIds );
+
+    /**
+     * Returns the list of layer IDs on which the task depends. The task will automatically
+     * be cancelled if any of these layers are about to be removed.
+     * @see setDependentLayers()
+     */
+    QStringList dependentLayerIds() const { return mDependentLayerIds; }
+
   signals:
 
     /**
@@ -278,6 +292,8 @@ class CORE_EXPORT QgsTask : public QObject
     };
     QList< SubTask > mSubTasks;
 
+    QStringList mDependentLayerIds;
+
 
     /**
      * Starts the task. Should not be public as only QgsTaskManagers can initiate tasks.
@@ -306,6 +322,7 @@ class CORE_EXPORT QgsTask : public QObject
 
 };
 
+
 Q_DECLARE_OPERATORS_FOR_FLAGS( QgsTask::Flags )
 
 /** \ingroup core
@@ -351,6 +368,7 @@ class CORE_EXPORT QgsTaskManager : public QObject
        * to the task manager for proper handling of dependencies.
        */
       QgsTaskList dependentTasks;
+
     };
 
     /** Adds a task to the manager. Ownership of the task is transferred
@@ -405,22 +423,20 @@ class CORE_EXPORT QgsTaskManager : public QObject
     //! @note not available in Python bindings
     QSet< long > dependencies( long taskId ) const;
 
-    /** Sets a list of layers on which as task is dependent. The task will automatically
-     * be cancelled if any of these layers are above to be removed.
-     * @param taskId task ID
-     * @param layerIds list of layer IDs
-     * @see dependentLayers()
-     */
-    void setDependentLayers( long taskId, const QStringList& layerIds );
-
     /** Returns a list of layers on which as task is dependent. The task will automatically
      * be cancelled if any of these layers are above to be removed.
      * @param taskId task ID
      * @returns list of layer IDs
-     * @see setDependentLayers()
+     * @see tasksDependentOnLayer()
      */
     QStringList dependentLayers( long taskId ) const;
 
+    /**
+     * Returns a list of tasks which depend on a layer.
+     * @see dependentLayers()
+     */
+    QList< QgsTask* > tasksDependentOnLayer( const QString& layerId ) const;
+
     /** Returns a list of the active (queued or running) tasks.
      * @see countActiveTasks()
      */

diff --git a/tests/src/core/testqgstaskmanager.cpp b/tests/src/core/testqgstaskmanager.cpp
@@ -1024,15 +1024,25 @@ void TestQgsTaskManager::layerDependencies()
   //test that remove layers cancels all tasks which are dependant on them
   TestTask* task = new TestTask();
   task->hold();
+  task->setDependentLayers( QStringList() << layer2->id() << layer3->id() );
+  QCOMPARE( task->dependentLayerIds(), QStringList() << layer2->id() << layer3->id() );
   long taskId = manager.addTask( task );
-  manager.setDependentLayers( taskId, QStringList() << layer2->id() << layer3->id() );
+  QCOMPARE( manager.dependentLayers( taskId ), QStringList() << layer2->id() << layer3->id() );
+  QVERIFY( manager.tasksDependentOnLayer( "xxx" ).isEmpty() );
+  QCOMPARE( manager.tasksDependentOnLayer( layer2->id() ), QList< QgsTask* >() << task );
+  QCOMPARE( manager.tasksDependentOnLayer( layer3->id() ), QList< QgsTask* >() << task );
 
   QCOMPARE( task->status(), QgsTask::OnHold );
   //removing layer1 should have no effect
   QgsMapLayerRegistry::instance()->removeMapLayers( QList< QgsMapLayer* >() << layer1 );
   QCOMPARE( task->status(), QgsTask::OnHold );
   //removing layer3 should cancel task
   QgsMapLayerRegistry::instance()->removeMapLayers( QList< QgsMapLayer* >() << layer3 );
+  while ( task->status() != QgsTask::Terminated )
+  {
+    QCoreApplication::processEvents();
+  }
+  flushEvents();
   QCOMPARE( task->status(), QgsTask::Terminated );
 
   QgsMapLayerRegistry::instance()->removeMapLayers( QList< QgsMapLayer* >() << layer2 );