[processing] Only load layers when absolutely required

This change avoids holding onto resources and layers from earlier iterations, and allows batch processing of many more items then is possible if we hold on to these layers
qgis · Nov 10, 2017 · 3fc9030 · 3fc9030
1 parent 30cefca
commit 3fc9030
Showing 1 changed file with 11 additions and 6 deletions.
diff --git a/python/plugins/processing/gui/BatchAlgorithmDialog.py b/python/plugins/processing/gui/BatchAlgorithmDialog.py
@@ -80,7 +80,6 @@ def accept(self):
         load = []
 
         feedback = self.createFeedback()
-        context = dataobjects.createContext(feedback)
 
         for row in range(self.mainWidget.tblParameters.rowCount()):
             col = 0
@@ -90,7 +89,7 @@ def accept(self):
                     continue
                 wrapper = self.mainWidget.wrappers[row][col]
                 parameters[param.name()] = wrapper.value()
-                if not param.checkValueIsAcceptable(wrapper.value(), context):
+                if not param.checkValueIsAcceptable(wrapper.value()):
                     self.bar.pushMessage("", self.tr('Wrong or missing parameter value: {0} (row {1})').format(
                                          param.description(), row + 1),
                                          level=QgsMessageBar.WARNING, duration=5)
@@ -104,11 +103,11 @@ def accept(self):
                 count_visible_outputs += 1
                 widget = self.mainWidget.tblParameters.cellWidget(row, col)
                 text = widget.getValue()
-                if out.checkValueIsAcceptable(text, context):
+                if out.checkValueIsAcceptable(text):
                     if isinstance(out, (QgsProcessingParameterRasterDestination,
                                         QgsProcessingParameterFeatureSink)):
                         # load rasters and sinks on completion
-                        parameters[out.name()] = QgsProcessingOutputLayerDefinition(text, context.project())
+                        parameters[out.name()] = QgsProcessingOutputLayerDefinition(text, QgsProject.instance())
                     else:
                         parameters[out.name()] = text
                     col += 1
@@ -145,6 +144,12 @@ def accept(self):
                 feedback.pushCommandInfo(pformat(parameters))
                 feedback.pushInfo('')
 
+                # important - we create a new context for each iteration
+                # this avoids holding onto resources and layers from earlier iterations,
+                # and allows batch processing of many more items then is possible
+                # if we hold on to these layers
+                context = dataobjects.createContext(feedback)
+
                 alg_start_time = time.time()
                 ret, results = execute(self.alg, parameters, context, feedback)
                 if ret:
@@ -159,9 +164,9 @@ def accept(self):
                 else:
                     break
 
-            feedback.pushInfo(self.tr('Batch execution completed in {0:0.2f} seconds'.format(time.time() - start_time)))
+                handleAlgorithmResults(self.alg, context, feedback, False)
 
-            handleAlgorithmResults(self.alg, context, feedback, False)
+        feedback.pushInfo(self.tr('Batch execution completed in {0:0.2f} seconds'.format(time.time() - start_time)))
 
         self.finish(algorithm_results)
         self.buttonCancel.setEnabled(False)