ViewerSystem.h

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/*  Copyright (C) 2003-2021 Free Electron Organization
    Any use of this software requires a license.  If a valid license
    was not distributed with this file, visit freeelectron.org. */

/** @file */

#pragma once

namespace fe
{
namespace ext
{

/**
 * Base class for Viewer Systems.
 *
 * A Viewer System is a System that reacts to draw notes. It is unique in that
 * it is aware of the thread it is being performed on. It delegates draw calls
 * to different viewports based on the current thread id.
 */
class FE_DL_EXPORT ViewerSystem :
    virtual public SystemI,
    public CastableAs<ViewerSystem>
{
public:
    /**
     * Draw stuff into the viewport.
     *
     * Should be overriden by final classes.
     *
     * @param viewportRecord The viewport on this thread.
     */
    virtual void draw(Record viewportRecord) = 0;

    /**
     * Updates the Viewer records.
     */
    void updateViewports(const t_note_id &note_id);

    /**
     * Perform processing due to having been signaled.
     *
     * This will delegate drawing to different viewports based on the current
     * thread id.
     */
    void perform(const t_note_id &a_note_id) override;

    void connectOrchestrator(sp<OrchestratorI> orchestrator) override
    {
        m_dataset = orchestrator->dataset();
        m_drawNote = orchestrator->connect(this, FE_NOTE_DRAW);
        orchestrator->connect(this, &ViewerSystem::updateViewports, FE_NOTE_ADDED_VIEWPORT);
        orchestrator->connect(this, &ViewerSystem::updateViewports, FE_NOTE_REMOVED_VIEWPORT);
    };

protected:
    sp<RecordGroup> m_dataset;

    /** ID of the draw note. */
    t_note_id m_drawNote;

    /** Accessors for viewport data. */
    AsViewport m_viewportAccessorSet;

    /** Available viewports. */
    std::map<std::thread::id, Record> m_viewportRecords;
    /** Mutex for viewportRecords. It is needed since this system has multiple
     * threads performing different notes. */
    #if FE_CPLUSPLUS >= 201703L
        std::shared_mutex m_viewportRecordsMutex; // C++17
    #else
        Mutex m_viewportRecordsMutex;
    #endif
};

} /* namespace ext */
} /* namespace fe */