diff transform/ModelTransformer.h @ 388:370aa9714ef5

* Move plugin/transform to plain transform.  This way transform can depend on
  model and GUI classes, but plugin doesn't have to.

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/transform/ModelTransformer.h	Wed Mar 12 18:02:17 2008 +0000
@@ -0,0 +1,111 @@
+/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */
+
+/*
+    Sonic Visualiser
+    An audio file viewer and annotation editor.
+    Centre for Digital Music, Queen Mary, University of London.
+    This file copyright 2006 Chris Cannam.
+   
+    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.  See the file
+    COPYING included with this distribution for more information.
+*/
+
+#ifndef _TRANSFORMER_H_
+#define _TRANSFORMER_H_
+
+#include "base/Thread.h"
+
+#include "data/model/Model.h"
+
+#include "Transform.h"
+
+/**
+ * A ModelTransformer turns one data model into another.
+ *
+ * Typically in this application, a ModelTransformer might have a
+ * DenseTimeValueModel as its input (e.g. an audio waveform) and a
+ * SparseOneDimensionalModel (e.g. detected beats) as its output.
+ *
+ * The ModelTransformer typically runs in the background, as a
+ * separate thread populating the output model.  The model is
+ * available to the user of the ModelTransformer immediately, but may
+ * be initially empty until the background thread has populated it.
+ */
+
+class ModelTransformer : public Thread
+{
+public:
+    virtual ~ModelTransformer();
+
+    class Input {
+    public:
+        Input(Model *m) : m_model(m), m_channel(-1) { }
+        Input(Model *m, int c) : m_model(m), m_channel(c) { }
+
+        Model *getModel() const { return m_model; }
+        void setModel(Model *m) { m_model = m; }
+
+        int getChannel() const { return m_channel; }
+        void setChannel(int c) { m_channel = c; }
+
+    protected:
+        Model *m_model;
+        int m_channel;
+    };
+
+    /**
+     * Hint to the processing thread that it should give up, for
+     * example because the process is going to exit or we want to get
+     * rid of the input model.  Caller should still wait() and/or
+     * delete the transform before assuming its input and output
+     * models are no longer required.
+     */
+    void abandon() { m_abandoned = true; }
+
+    /**
+     * Return the input model for the transform.
+     */
+    Model *getInputModel()  { return m_input.getModel(); }
+
+    /**
+     * Return the input channel spec for the transform.
+     */
+    int getInputChannel() { return m_input.getChannel(); }
+
+    /**
+     * Return the output model created by the transform.  Returns a
+     * null model if the transform could not be initialised; an error
+     * message may be available via getMessage() in this situation.
+     */
+    Model *getOutputModel() { return m_output; }
+
+    /**
+     * Return the output model, also detaching it from the transformer
+     * so that it will not be deleted when the transformer is.  The
+     * caller takes ownership of the model.
+     */
+    Model *detachOutputModel() { m_detached = true; return m_output; }
+
+    /**
+     * Return a warning or error message.  If getOutputModel returned
+     * a null pointer, this should contain a fatal error message for
+     * the transformer; otherwise it may contain a warning to show to
+     * the user about e.g. suboptimal block size or whatever.  
+     */
+    QString getMessage() const { return m_message; }
+
+protected:
+    ModelTransformer(Input input, const Transform &transform);
+
+    Transform m_transform;
+    Input m_input; // I don't own the model in this
+    Model *m_output; // I own this, unless...
+    bool m_detached; // ... this is true.
+    bool m_abandoned;
+    QString m_message;
+};
+
+#endif