Create a QgsProcessingAlgRunnerTask task

Allows background execution of processing algorithms.

Not exposed anywhere in GUI (yet)

python/core/core.sip

@@ -285,6 +285,7 @@
 %Include metadata/qgslayermetadatavalidator.sip
 
 %Include processing/qgsprocessingalgorithm.sip
+%Include processing/qgsprocessingalgrunnertask.sip
 %Include processing/qgsprocessingcontext.sip
 %Include processing/qgsprocessingfeedback.sip
 %Include processing/qgsprocessingoutputs.sip

python/core/processing/qgsprocessingalgorithm.sip

@@ -383,6 +383,8 @@ QFlags<QgsProcessingAlgorithm::Flag> operator|(QgsProcessingAlgorithm::Flag f1,
 
 
 
+
+
 /************************************************************************
  * This file has been generated automatically from                      *
  *                                                                      *

python/core/processing/qgsprocessingalgrunnertask.sip

@@ -0,0 +1,50 @@
+/************************************************************************
+ * This file has been generated automatically from                      *
+ *                                                                      *
+ * src/core/processing/qgsprocessingalgrunnertask.h                     *
+ *                                                                      *
+ * Do not edit manually ! Edit header and run scripts/sipify.pl again   *
+ ************************************************************************/
+
+
+
+
+
+class QgsProcessingAlgRunnerTask : QgsTask
+{
+%Docstring
+ QgsTask task which runs a QgsProcessingAlgorithm in a background task.
+.. versionadded:: 3.0
+%End
+
+%TypeHeaderCode
+#include "qgsprocessingalgrunnertask.h"
+%End
+  public:
+
+    QgsProcessingAlgRunnerTask( const QgsProcessingAlgorithm *algorithm,
+                                const QVariantMap &parameters,
+                                QgsProcessingContext &context );
+%Docstring
+ Constructor for QgsProcessingAlgRunnerTask. Takes an ``algorithm``, algorithm ``parameters``
+ and processing ``context``.
+%End
+
+    virtual void cancel();
+
+  protected:
+
+    virtual bool run();
+    virtual void finished( bool result );
+
+};
+
+
+
+/************************************************************************
+ * This file has been generated automatically from                      *
+ *                                                                      *
+ * src/core/processing/qgsprocessingalgrunnertask.h                     *
+ *                                                                      *
+ * Do not edit manually ! Edit header and run scripts/sipify.pl again   *
+ ************************************************************************/

src/core/CMakeLists.txt

@@ -95,6 +95,7 @@ SET(QGIS_CORE_SRCS
 
   processing/qgsnativealgorithms.cpp
   processing/qgsprocessingalgorithm.cpp
+  processing/qgsprocessingalgrunnertask.cpp
   processing/qgsprocessingoutputs.cpp
   processing/qgsprocessingparameters.cpp
   processing/qgsprocessingprovider.cpp
@@ -633,6 +634,7 @@ SET(QGIS_CORE_MOC_HDRS
   composer/qgslayoutmanager.h
   composer/qgspaperitem.h
 
+  processing/qgsprocessingalgrunnertask.h
   processing/qgsprocessingfeedback.h
   processing/qgsprocessingprovider.h
   processing/qgsprocessingregistry.h

src/core/processing/qgsprocessingalgorithm.cpp

@@ -250,3 +250,5 @@ QStringList QgsProcessingAlgorithm::parameterAsFields( const QVariantMap &parame
 {
   return QgsProcessingParameters::parameterAsFields( parameterDefinition( name ), parameters, name, context );
 }
+
+

src/core/processing/qgsprocessingalgorithm.h

@@ -378,6 +378,8 @@ class CORE_EXPORT QgsProcessingAlgorithm
 };
 Q_DECLARE_OPERATORS_FOR_FLAGS( QgsProcessingAlgorithm::Flags )
 
+
+
 #endif // QGSPROCESSINGALGORITHM_H
 
 

src/core/processing/qgsprocessingalgrunnertask.cpp

@@ -0,0 +1,56 @@
+/***************************************************************************
+                         qgsprocessingalgrunnertask.cpp
+                         ------------------------------
+    begin                : May 2017
+    copyright            : (C) 2017 by Nyall Dawson
+    email                : nyall dot dawson at gmail dot com
+ ***************************************************************************/
+
+/***************************************************************************
+ *                                                                         *
+ *   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.                                   *
+ *                                                                         *
+ ***************************************************************************/
+
+#include "qgsprocessingalgrunnertask.h"
+#include "qgsprocessingfeedback.h"
+#include "qgsprocessingcontext.h"
+#include "qgsprocessingalgorithm.h"
+#include "qgsprocessingutils.h"
+#include "qgsvectorlayer.h"
+
+QgsProcessingAlgRunnerTask::QgsProcessingAlgRunnerTask( const QgsProcessingAlgorithm *algorithm, const QVariantMap &parameters, QgsProcessingContext &context )
+  : mAlgorithm( algorithm )
+  , mParameters( parameters )
+  , mContext( context )
+{
+  mFeedback.reset( new QgsProcessingFeedback() );
+}
+
+void QgsProcessingAlgRunnerTask::cancel()
+{
+  mFeedback->cancel();
+}
+
+bool QgsProcessingAlgRunnerTask::run()
+{
+  connect( mFeedback.get(), &QgsFeedback::progressChanged, this, &QgsProcessingAlgRunnerTask::setProgress );
+  mResults = mAlgorithm->run( mParameters, mContext, mFeedback.get() );
+  return !mFeedback->isCanceled();
+}
+
+void QgsProcessingAlgRunnerTask::finished( bool result )
+{
+  Q_UNUSED( result );
+  if ( !mResults.isEmpty() )
+  {
+    QgsMapLayer *layer = QgsProcessingUtils::mapLayerFromString( mResults.value( "OUTPUT_LAYER" ).toString(), mContext );
+    if ( layer )
+    {
+      mContext.project()->addMapLayer( mContext.temporaryLayerStore()->takeMapLayer( layer ) );
+    }
+  }
+}

src/core/processing/qgsprocessingalgrunnertask.h

@@ -0,0 +1,68 @@
+/***************************************************************************
+                         qgsprocessingalgrunnertask.h
+                         ------------------------
+    begin                : May 2017
+    copyright            : (C) 2017 by Nyall Dawson
+    email                : nyall dot dawson at gmail dot com
+ ***************************************************************************/
+
+/***************************************************************************
+ *                                                                         *
+ *   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 QGSPROCESSINGALGRUNNERTASK_H
+#define QGSPROCESSINGALGRUNNERTASK_H
+
+#include "qgis_core.h"
+#include "qgis.h"
+#include "qgstaskmanager.h"
+#include "qgsprocessingfeedback.h"
+
+class QgsProcessingAlgorithm;
+class QgsProcessingContext;
+
+/**
+ * \class QgsProcessingAlgRunnerTask
+ * \ingroup core
+ * QgsTask task which runs a QgsProcessingAlgorithm in a background task.
+ * \since QGIS 3.0
+ */
+class CORE_EXPORT QgsProcessingAlgRunnerTask : public QgsTask
+{
+    Q_OBJECT
+
+  public:
+
+    /**
+     * Constructor for QgsProcessingAlgRunnerTask. Takes an \a algorithm, algorithm \a parameters
+     * and processing \a context.
+     */
+    QgsProcessingAlgRunnerTask( const QgsProcessingAlgorithm *algorithm,
+                                const QVariantMap &parameters,
+                                QgsProcessingContext &context );
+
+    virtual void cancel() override;
+
+  protected:
+
+    virtual bool run() override;
+    virtual void finished( bool result ) override;
+
+  private:
+
+    const QgsProcessingAlgorithm *mAlgorithm = nullptr;
+    QVariantMap mParameters;
+    QVariantMap mResults;
+    QgsProcessingContext &mContext;
+    std::unique_ptr< QgsProcessingFeedback > mFeedback;
+
+};
+
+#endif // QGSPROCESSINGALGRUNNERTASK_H
+
+