# HG changeset patch
# User Chris Cannam
# Date 1402907292 -3600
# Node ID f5c914661f6fdc7f05c2c980b0d21350d5933428
# Parent  5302c548adadd5e3ddb5fd2eafa45ce3033183e7
Cancel async layer creation in Tony when selection is changed during it

diff -r 5302c548adad -r f5c914661f6f framework/Document.cpp
--- a/framework/Document.cpp	Fri Jun 13 13:51:17 2014 +0100
+++ b/framework/Document.cpp	Mon Jun 16 09:28:12 2014 +0100
@@ -275,24 +275,33 @@
         }
         vector<Layer *> layers = m_doc->createLayersForDerivedModels
             (models, names);
-        m_handler->layersCreated(m_primary, layers);
+        m_handler->layersCreated(this, m_primary, layers);
         delete this;
     }
 
     void
     noMoreModelsAvailable() {
         std::cerr << "AdditionalModelConverter::noMoreModelsAvailable" << std::endl;
-        m_handler->layersCreated(m_primary, vector<Layer *>());
+        m_handler->layersCreated(this, m_primary, vector<Layer *>());
         delete this;
     }
 
+    void cancel() {
+        foreach (Layer *layer, m_primary) {
+            Model *model = layer->getModel();
+            if (model) {
+                model->abandon();
+            }
+        }
+    }
+
 private:
     Document *m_doc;
     vector<Layer *> m_primary;
     Document::LayerCreationHandler *m_handler; //!!! how to handle destruction of this?
 };
 
-void
+Document::LayerCreationAsyncHandle
 Document::createDerivedLayersAsync(const Transforms &transforms,
                                    const ModelTransformer::Input &input,
                                    LayerCreationHandler *handler)
@@ -318,10 +327,21 @@
     if (newModels.empty()) {
         //!!! This identifier may be wrong!
         emit modelGenerationFailed(transforms[0].getIdentifier(), message);
+        //!!! what to do with amc?
     } else if (message != "") {
         //!!! This identifier may be wrong!
         emit modelGenerationWarning(transforms[0].getIdentifier(), message);
+        //!!! what to do with amc?
     }
+
+    return amc;
+}
+
+void
+Document::cancelAsyncLayerCreation(Document::LayerCreationAsyncHandle h)
+{
+    AdditionalModelConverter *conv = static_cast<AdditionalModelConverter *>(h);
+    conv->cancel();
 }
 
 vector<Layer *>
diff -r 5302c548adad -r f5c914661f6f framework/Document.h
--- a/framework/Document.h	Fri Jun 13 13:51:17 2014 +0100
+++ b/framework/Document.h	Mon Jun 16 09:28:12 2014 +0100
@@ -128,6 +128,8 @@
     std::vector<Layer *> createDerivedLayers(const Transforms &,
                                              const ModelTransformer::Input &);
 
+    typedef void *LayerCreationAsyncHandle;
+
     class LayerCreationHandler {
     public:
         virtual ~LayerCreationHandler() { }
@@ -137,9 +139,12 @@
          * models, listed in the same order as the input models. The
          * additional layers vector contains any layers (from all
          * models) that were returned separately at the end of
-         * processing.
+         * processing. The handle indicates which async process this
+         * callback was initiated by. It must not be used again after
+         * this function returns.
          */
-        virtual void layersCreated(std::vector<Layer *> primary,
+        virtual void layersCreated(LayerCreationAsyncHandle handle,
+                                   std::vector<Layer *> primary,
                                    std::vector<Layer *> additional) = 0;
     };
 
@@ -148,11 +153,21 @@
      * identical apart from the output (i.e. must use the same plugin
      * and configuration). This method returns after initialising the
      * transformer process, and the layers are returned through a
-     * subsequent call to the provided handler (which must be non-null).
+     * subsequent call to the provided handler (which must be
+     * non-null). The handle returned will be passed through to the
+     * handler callback, and may be also used for cancelling the task.
      */
-    void createDerivedLayersAsync(const Transforms &,
-                                  const ModelTransformer::Input &,
-                                  LayerCreationHandler *handler);
+    LayerCreationAsyncHandle createDerivedLayersAsync(const Transforms &,
+                                                      const ModelTransformer::Input &,
+                                                      LayerCreationHandler *handler);
+
+    /**
+     * Indicate that the async layer creation task associated with the
+     * given handle should be cancelled. There is no guarantee about
+     * what this will mean, and the handler callback may still be
+     * called.
+     */
+    void cancelAsyncLayerCreation(LayerCreationAsyncHandle handle);
 
     /**
      * Delete the given layer, and also its associated model if no