/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */

/*

 * This file is part of the LibreOffice project.

 *

 * This Source Code Form is subject to the terms of the Mozilla Public

 * License, v. 2.0. If a copy of the MPL was not distributed with this

 * file, You can obtain one at http://mozilla.org/MPL/2.0/.

 *

 * This file incorporates work covered by the following license notice:

 *

 *   Licensed to the Apache Software Foundation (ASF) under one or more

 *   contributor license agreements. See the NOTICE file distributed

 *   with this work for additional information regarding copyright

 *   ownership. The ASF licenses this file to you under the Apache

 *   License, Version 2.0 (the "License"); you may not use this file

 *   except in compliance with the License. You may obtain a copy of

 *   the License at http://www.apache.org/licenses/LICENSE-2.0 .

 */

#pragma once

#include "MasterPageContainer.hxx"

#include "MasterPageDescriptor.hxx"

#include <vcl/timer.hxx>

#include <memory>

namespace sd::sidebar {

/** The queue stores and processes all requests from a MasterPageContainer

    for the creation of previews.

    The order of request processing and its timing is controlled by a

    heuristic that uses values given with each request and which is

    controlled by various parameters that are described below.

*/

class MasterPageContainerQueue final

{

public:

    class ContainerAdapter {

    public:

        virtual bool UpdateDescriptor (

            const SharedMasterPageDescriptor& rpDescriptor,

            bool bForcePageObject,

            bool bForcePreview,

            bool bSendEvents) = 0;

    protected:

        ~ContainerAdapter() {}

    };

    static MasterPageContainerQueue* Create (

        const std::weak_ptr<ContainerAdapter>& rpContainer);

    ~MasterPageContainerQueue();

    /** This method is typically called for entries in the container for

        which GetPreviewState() returns OS_CREATABLE.  The creation of the

        preview is then scheduled to be executed asynchronously at a later

        point in time.  When the preview is available the change listeners

        will be notified.

    */

    bool RequestPreview (const SharedMasterPageDescriptor& rDescriptor);

    /** Return <TRUE/> when there is a request currently in the queue for

        the given token.

    */

    bool HasRequest (MasterPageContainer::Token aToken) const;

    /** Return <TRUE/> when there is at least one request in the queue.

    */

    bool IsEmpty() const;

    /** After this call the queue does not wait anymore for requests with

        higher priority when only a small number of requests with lower

        priority are present.  This method should be called when all

        templates are inserted into the MasterPageContainer.

    */

    void ProcessAllRequests();

private:

    std::weak_ptr<ContainerAdapter> mpWeakContainer;

    class PreviewCreationRequest;

    class RequestQueue;

    std::unique_ptr<RequestQueue> mpRequestQueue;

    Timer maDelayedPreviewCreationTimer;

    sal_uInt32 mnRequestsServedCount;

    // There are a couple of values that define various aspects of the

    // heuristic that defines the order and timing in which requests for

    // preview creation are processed.

    /** The time to wait (in milliseconds) between the creation of previews.

    */

    static const sal_Int32 snDelayedCreationTimeout;

    /** The time to wait when the system is not idle.

    */

    static const sal_Int32 snDelayedCreationTimeoutWhenNotIdle;

    /** Requests for previews of master pages in a document have their

        priority increased by this value.

    */

    static const sal_Int32 snMasterPagePriorityBoost;

    /** When only requests which a priority lower than this threshold exist

        and not many requests have been made yet then wait with processing

        them until more requests are present.

    */

    static const sal_Int32 snWaitForMoreRequestsPriorityThreshold;

    /** When only requests which a priority lower than a threshold exist

        and not more requests than this number have been made or already

        processed then wait with processing them until more requests are

        present.

    */

    static sal_uInt32 snWaitForMoreRequestsCount;

    explicit MasterPageContainerQueue (std::weak_ptr<ContainerAdapter> pContainer);

    void LateInit();

    /** Calculate the priority that defines the order in which requests

        are processed.

    */

    static sal_Int32 CalculatePriority (const SharedMasterPageDescriptor& rDescriptor);

    DECL_LINK(DelayedPreviewCreation, Timer *, void);

};

} // end of namespace sd::sidebar

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