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/* ============================================================
*
* This file is a part of digiKam project
* http://www.digikam.org
*
* Date : 2006-01-16
* Description : image file IO threaded interface.
*
* Copyright (C) 2005-2007 by Marcel Wiesweg <[email protected]>
* Copyright (C) 2005-2007 by Gilles Caulier <caulier dot gilles at gmail dot com>
*
* 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, or (at your option)
* any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* ============================================================ */
#ifndef MANAGED_LOAD_SAVE_THREAD_H
#define MANAGED_LOAD_SAVE_THREAD_H
#include "loadsavethread.h"
namespace Digikam
{
class LoadingTask;
class DIGIKAM_EXPORT ManagedLoadSaveThread : public LoadSaveThread
{
public:
// Termination is controlled by setting the TerminationPolicy
// Default is TerminationPolicyTerminateLoading
ManagedLoadSaveThread();
~ManagedLoadSaveThread();
enum LoadingPolicy
{
// Load image immediately, remove and stop all previous loading tasks.
LoadingPolicyFirstRemovePrevious,
// Prepend loading in front of all other tasks, but wait for the current task to finish.
// No other tasks will be removed, preloading tasks will be stopped and postponed.
LoadingPolicyPrepend,
// Append loading task to the end of the list, but in front of all preloading tasks.
// No other tasks will be removed, preloading tasks will be stopped and postponed.
// This is similar to the simple load() operation from LoadSaveThread, except for the
// special care taken for preloading.
LoadingPolicyAppend,
// Preload image, i.e. load it with low priority when no other tasks are scheduled.
// All other tasks will take precedence, and preloading tasks will be stopped and
// postponed when another task is added.
// No progress info will be sent for preloaded images
LoadingPolicyPreload
};
enum TerminationPolicy
{
// Wait for saving tasks, stop and remove loading tasks
// This is the default.
TerminationPolicyTerminateLoading,
// Wait for loading and saving tasks, stop and remove preloading tasks
TerminationPolicyTerminatePreloading,
// Wait for all pending tasks
TerminationPolicyWait
};
enum LoadingTaskFilter
{
// filter all loading tasks
LoadingTaskFilterAll,
// filter only tasks with preloading policy
LoadingTaskFilterPreloading
};
// used by SharedLoadSaveThread only
enum LoadingMode
{
// no sharing of loading process, no caching of image
LoadingModeNormal,
// loading process is shared, image is cached
LoadingModeShared
};
// Append a task to load the given file to the task list.
// If there is already a task for the given file, it will possibly be rescheduled,
// but no second task will be added.
// Only loading tasks will - if required by the policy - be stopped or removed,
// saving tasks will not be touched.
void load(LoadingDescription description, LoadingPolicy policy = LoadingPolicyAppend);
// Stop and remove tasks filtered by filePath and policy.
// If filePath isNull, applies to all file paths.
void stopLoading(const TQString& filePath = TQString(), LoadingTaskFilter filter = LoadingTaskFilterAll);
// Same than previous method, but Stop and remove tasks filtered by LoadingDescription.
void stopLoading(const LoadingDescription& desc, LoadingTaskFilter filter = LoadingTaskFilterAll);
// Stop and remove saving tasks filtered by filePath.
// If filePath isNull, applies to all file paths.
void stopSaving(const TQString& filePath = TQString());
// Append a task to save the image to the task list
void save(DImg &image, const TQString& filePath, const TQString &format);
void setTerminationPolicy(TerminationPolicy terminationPolicy);
protected:
void load(LoadingDescription description, LoadingMode loadingMode,
LoadingPolicy policy = LoadingPolicyAppend, AccessMode mode = AccessModeReadWrite);
void loadPreview(LoadingDescription description);
private:
LoadingTask *checkLoadingTask(class LoadSaveTask *task, LoadingTaskFilter filter);
LoadingTask *findExistingTask(const LoadingDescription &description);
LoadingTask *createLoadingTask(const LoadingDescription &description, bool preloading, LoadingMode loadingMode, AccessMode accessMode);
void removeLoadingTasks(const LoadingDescription &description, LoadingTaskFilter filter);
TerminationPolicy m_terminationPolicy;
};
} // namespace Digikam
#endif // MANAGED_LOAD_SAVE_THREAD_H
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