1 files changed, 424 insertions, 0 deletions
diff --git a/src/libs/threadimageio/loadsavetask.cpp b/src/libs/threadimageio/loadsavetask.cpp
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+++ b/src/libs/threadimageio/loadsavetask.cpp
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+/* ============================================================
+ *
+ * This file is a part of digiKam project
+ * http://www.digikam.org
+ *
+ * Date        : 2005-12-17
+ * Description : image file IO threaded interface.
+ *
+ * Copyright (C) 2005-2007 by Marcel Wiesweg <marcel.wiesweg@gmx.de>
+ * 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.
+ *
+ * ============================================================ */
+
+#include "loadsavetask.h"
+
+// TQt includes.
+
+#include <tqapplication.h>
+
+// Local includes.
+
+#include "ddebug.h"
+#include "loadsavethread.h"
+#include "managedloadsavethread.h"
+#include "sharedloadsavethread.h"
+#include "loadingcache.h"
+
+namespace Digikam
+{
+
+void LoadingProgressEvent::notify(LoadSaveThread *thread)
+{
+    thread->loadingProgress(m_loadingDescription, m_progress);
+}
+
+void SavingProgressEvent::notify(LoadSaveThread *thread)
+{
+    thread->savingProgress(m_filePath, m_progress);
+}
+
+void StartedLoadingEvent::notify(LoadSaveThread *thread)
+{
+    thread->imageStartedLoading(m_loadingDescription);
+}
+
+void StartedSavingEvent::notify(LoadSaveThread *thread)
+{
+    thread->imageStartedSaving(m_filePath);
+}
+
+void LoadedEvent::notify(LoadSaveThread *thread)
+{
+    thread->imageLoaded(m_loadingDescription, m_img);
+}
+
+void MoreCompleteLoadingAvailableEvent::notify(LoadSaveThread *thread)
+{
+    thread->moreCompleteLoadingAvailable(m_oldDescription, m_newDescription);
+}
+
+void SavedEvent::notify(LoadSaveThread *thread)
+{
+    thread->imageSaved(m_filePath, m_success);
+}
+
+//---------------------------------------------------------------------------------------------------
+
+void LoadingTask::execute()
+{
+    if (m_loadingTaskStatus == LoadingTaskStatusStopping)
+        return;
+    DImg img(m_loadingDescription.filePath, this, m_loadingDescription.rawDecodingSettings);
+    m_thread->taskHasFinished();
+    TQApplication::postEvent(m_thread, new LoadedEvent(m_loadingDescription.filePath, img));
+}
+
+LoadingTask::TaskType LoadingTask::type()
+{
+    return TaskTypeLoading;
+}
+
+void LoadingTask::progressInfo(const DImg *, float progress)
+{
+    if (m_loadingTaskStatus == LoadingTaskStatusLoading)
+    {
+        if (m_thread->querySendNotifyEvent())
+            TQApplication::postEvent(m_thread, new LoadingProgressEvent(m_loadingDescription.filePath, progress));
+    }
+}
+
+bool LoadingTask::continueQuery(const DImg *)
+{
+    return m_loadingTaskStatus != LoadingTaskStatusStopping;
+}
+
+void LoadingTask::setStatus(LoadingTaskStatus status)
+{
+    m_loadingTaskStatus = status;
+}
+
+
+// This is a hack needed to prevent hanging when a TDEProcess-based loader (raw loader)
+// is waiting for the process to finish, but the main thread is waiting
+// for the thread to finish and no TDEProcess events are delivered.
+// Remove when porting to TQt4.
+bool LoadingTask::isShuttingDown()
+{
+    return m_thread->isShuttingDown();
+}
+
+//---------------------------------------------------------------------------------------------------
+
+void SharedLoadingTask::execute()
+{
+    if (m_loadingTaskStatus == LoadingTaskStatusStopping)
+        return;
+    // send StartedLoadingEvent from each single Task, not via LoadingProcess list
+    TQApplication::postEvent(m_thread, new StartedLoadingEvent(m_loadingDescription.filePath));
+
+    LoadingCache *cache = LoadingCache::cache();
+    {
+        LoadingCache::CacheLock lock(cache);
+
+        // find possible cached images
+        DImg *cachedImg = 0;
+        TQStringList lookupKeys = m_loadingDescription.lookupCacheKeys();
+        for ( TQStringList::Iterator it = lookupKeys.begin(); it != lookupKeys.end(); ++it ) {
+            if ( (cachedImg = cache->retrieveImage(*it)) )
+                break;
+        }
+
+        if (cachedImg)
+        {
+            // image is found in image cache, loading is successful
+            DImg img(*cachedImg);
+            if (accessMode() == LoadSaveThread::AccessModeReadWrite)
+                img = img.copy();
+            TQApplication::postEvent(m_thread, new LoadedEvent(m_loadingDescription.filePath, img));
+            return;
+        }
+        else
+        {
+            // find possible running loading process
+            m_usedProcess = 0;
+            for ( TQStringList::Iterator it = lookupKeys.begin(); it != lookupKeys.end(); ++it ) {
+                if ( (m_usedProcess = cache->retrieveLoadingProcess(*it)) )
+                {
+                    break;
+                }
+            }
+
+            if (m_usedProcess)
+            {
+                // Other process is right now loading this image.
+                // Add this task to the list of listeners and
+                // attach this thread to the other thread, wait until loading
+                // has finished.
+                m_usedProcess->addListener(this);
+                // break loop when either the loading has completed, or this task is being stopped
+                while ( !m_usedProcess->completed() && m_loadingTaskStatus != LoadingTaskStatusStopping )
+                    lock.timedWait();
+                // remove listener from process
+                m_usedProcess->removeListener(this);
+                // wake up the process which is waiting until all listeners have removed themselves
+                lock.wakeAll();
+                // set to 0, as checked in setStatus
+                m_usedProcess = 0;
+                //DDebug() << "SharedLoadingTask " << this << ": waited" << endl;
+                return;
+            }
+            else
+            {
+                // Neither in cache, nor currently loading in different thread.
+                // Load it here and now, add this LoadingProcess to cache list.
+                cache->addLoadingProcess(this);
+                // Add this to the list of listeners
+                addListener(this);
+                // for use in setStatus
+                m_usedProcess = this;
+                // Notify other processes that we are now loading this image.
+                // They might be interested - see notifyNewLoadingProcess below
+                cache->notifyNewLoadingProcess(this, m_loadingDescription);
+            }
+        }
+    }
+
+    // load image
+    DImg img(m_loadingDescription.filePath, this, m_loadingDescription.rawDecodingSettings);
+
+    bool isCached = false;
+    {
+        LoadingCache::CacheLock lock(cache);
+        // put (valid) image into cache of loaded images
+        if (!img.isNull())
+            isCached = cache->putImage(m_loadingDescription.cacheKey(), new DImg(img), m_loadingDescription.filePath);
+        // remove this from the list of loading processes in cache
+        cache->removeLoadingProcess(this);
+    }
+
+    // following the golden rule to avoid deadlocks, do this when CacheLock is not held
+    m_thread->taskHasFinished();
+
+    {
+        LoadingCache::CacheLock lock(cache);
+        //DDebug() << "SharedLoadingTask " << this << ": image loaded, " << img.isNull() << endl;
+        // indicate that loading has finished so that listeners can stop waiting
+        m_completed = true;
+
+        // Optimize so that no unnecessary copying is done.
+        // If image has been put in cache, the initial copy has been consumed for this.
+        // If image is too large for cache, the initial copy is still available.
+        bool usedInitialCopy = isCached;
+        // dispatch image to all listeners, including this
+        for (LoadingProcessListener *l = m_listeners.first(); l; l = m_listeners.next())
+        {
+            // This code sends a copy only when ReadWrite access is requested.
+            // Otherwise, the image from the cache is sent.
+            // As the image in the cache will be deleted from any thread, the explicit sharing
+            // needs to be thread-safe to avoid the risk of memory leaks.
+            // This is the case only for TQt4, so uncomment this code when porting.
+            /*
+            if (l->accessMode() == LoadSaveThread::AccessModeReadWrite)
+            {
+                // If a listener requested ReadWrite access, it gets a deep copy.
+                // DImg is explicitly shared.
+                DImg copy = img.copy();
+                TQApplication::postEvent(l->eventReceiver(), new LoadedEvent(m_loadingDescription.filePath, copy));
+            }
+            else
+                TQApplication::postEvent(l->eventReceiver(), new LoadedEvent(m_loadingDescription.filePath, img));
+            */
+            // TQt3: The same copy for all Read listeners (it is assumed that they will delete it only in the main thread),
+            // an extra copy for each ReadWrite listener
+            DImg readerCopy;
+            if (l->accessMode() == LoadSaveThread::AccessModeReadWrite)
+            {
+                // If a listener requested ReadWrite access, it gets a deep copy.
+                // DImg is explicitly shared.
+                DImg copy;
+                if (usedInitialCopy)
+                {
+                    copy = img.copy();
+                }
+                else
+                {
+                    copy = img;
+                    usedInitialCopy = true;
+                }
+                TQApplication::postEvent(l->eventReceiver(), new LoadedEvent(m_loadingDescription, copy));
+            }
+            else
+            {
+                if (readerCopy.isNull())
+                {
+                    if (usedInitialCopy)
+                    {
+                        readerCopy = img.copy();
+                    }
+                    else
+                    {
+                        readerCopy = img;
+                        usedInitialCopy = true;
+                    }
+                }
+                TQApplication::postEvent(l->eventReceiver(), new LoadedEvent(m_loadingDescription, readerCopy));
+            }
+        }
+
+        // remove myself from list of listeners
+        removeListener(this);
+        // wake all listeners waiting on cache condVar, so that they remove themselves
+        lock.wakeAll();
+        // wait until all listeners have removed themselves
+        while (m_listeners.count() != 0)
+            lock.timedWait();
+        // set to 0, as checked in setStatus
+        m_usedProcess = 0;
+    }
+}
+
+void SharedLoadingTask::progressInfo(const DImg *, float progress)
+{
+    if (m_loadingTaskStatus == LoadingTaskStatusLoading)
+    {
+        LoadingCache *cache = LoadingCache::cache();
+        LoadingCache::CacheLock lock(cache);
+
+        for (LoadingProcessListener *l = m_listeners.first(); l; l = m_listeners.next())
+        {
+            if (l->querySendNotifyEvent())
+                TQApplication::postEvent(l->eventReceiver(), new LoadingProgressEvent(m_loadingDescription, progress));
+        }
+    }
+}
+
+bool SharedLoadingTask::continueQuery(const DImg *)
+{
+    // If this is called, the thread is currently loading an image.
+    // In shared loading, we cannot stop until all listeners have been removed as well
+    return (m_loadingTaskStatus != LoadingTaskStatusStopping) || (m_listeners.count() != 0);
+}
+
+void SharedLoadingTask::setStatus(LoadingTaskStatus status)
+{
+    m_loadingTaskStatus = status;
+    if (m_loadingTaskStatus == LoadingTaskStatusStopping)
+    {
+        LoadingCache *cache = LoadingCache::cache();
+        LoadingCache::CacheLock lock(cache);
+
+        // check for m_usedProcess, to avoid race condition that it has finished before
+        if (m_usedProcess)
+        {
+            // remove this from list of listeners - check in continueQuery() of active thread
+            m_usedProcess->removeListener(this);
+            // wake all listeners - particularly this - from waiting on cache condvar
+            lock.wakeAll();
+        }
+    }
+}
+
+bool SharedLoadingTask::completed()
+{
+    return m_completed;
+}
+
+TQString SharedLoadingTask::filePath()
+{
+    return m_loadingDescription.filePath;
+}
+
+TQString SharedLoadingTask::cacheKey()
+{
+    return m_loadingDescription.cacheKey();
+}
+
+void SharedLoadingTask::addListener(LoadingProcessListener *listener)
+{
+    m_listeners.append(listener);
+}
+
+void SharedLoadingTask::removeListener(LoadingProcessListener *listener)
+{
+    m_listeners.remove(listener);
+}
+
+void SharedLoadingTask::notifyNewLoadingProcess(LoadingProcess *process, LoadingDescription description)
+{
+    // Ok, we are notified that another task has been started in another thread.
+    // We are of course only interested if the task loads the same file,
+    // and we are right now loading a reduced version, and the other task is loading the full version.
+    // In this case, we notify our own thread (a signal to the API user is emitted) of this.
+    // The fact that we are receiving the method call shows that this task is registered with the LoadingCache,
+    // somewhere in between the calls to addLoadingProcess(this) and removeLoadingProcess(this) above.
+    if (process != this &&
+        m_loadingDescription.isReducedVersion() &&
+        m_loadingDescription.equalsIgnoreReducedVersion(description) &&
+        !description.isReducedVersion()
+       )
+    {
+        for (LoadingProcessListener *l = m_listeners.first(); l; l = m_listeners.next())
+        {
+            TQApplication::postEvent(l->eventReceiver(), new MoreCompleteLoadingAvailableEvent(m_loadingDescription, description));
+        }
+    }
+}
+
+bool SharedLoadingTask::querySendNotifyEvent()
+{
+    return m_thread->querySendNotifyEvent();
+}
+
+TQObject *SharedLoadingTask::eventReceiver()
+{
+    return m_thread;
+}
+
+LoadSaveThread::AccessMode SharedLoadingTask::accessMode()
+{
+    return m_accessMode;
+}
+
+//---------------------------------------------------------------------------------------------------
+
+void SavingTask::execute()
+{
+    bool success = m_img.save(m_filePath, m_format, this);
+    m_thread->taskHasFinished();
+    TQApplication::postEvent(m_thread, new SavedEvent(m_filePath, success));
+};
+
+LoadingTask::TaskType SavingTask::type()
+{
+    return TaskTypeSaving;
+}
+
+void SavingTask::progressInfo(const DImg *, float progress)
+{
+    if (m_thread->querySendNotifyEvent())
+        TQApplication::postEvent(m_thread, new SavingProgressEvent(m_filePath, progress));
+}
+
+bool SavingTask::continueQuery(const DImg *)
+{
+    return m_savingTaskStatus != SavingTaskStatusStopping;
+}
+
+void SavingTask::setStatus(SavingTaskStatus status)
+{
+    m_savingTaskStatus = status;
+}
+
+}   //namespace Digikam