src/com/android/gallery3d/app/AlbumSetDataLoader.java - platform/packages/apps/Gallery2 - Git at Google

 /*
  * Copyright (C) 2010 The Android Open Source Project
  *
  * Licensed 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
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 package com.android.gallery3d.app;

 import android.os.Handler;
 import android.os.Message;
 import android.os.Process;

 import com.android.gallery3d.common.Utils;
 import com.android.gallery3d.data.ContentListener;
 import com.android.gallery3d.data.MediaItem;
 import com.android.gallery3d.data.MediaObject;
 import com.android.gallery3d.data.MediaSet;
 import com.android.gallery3d.data.Path;
 import com.android.gallery3d.ui.SynchronizedHandler;

 import java.util.Arrays;
 import java.util.concurrent.Callable;
 import java.util.concurrent.ExecutionException;
 import java.util.concurrent.FutureTask;

 public class AlbumSetDataLoader {
     @SuppressWarnings("unused")
     private static final String TAG = "AlbumSetDataAdapter";

     private static final int INDEX_NONE = -1;

     private static final int MIN_LOAD_COUNT = 4;

     private static final int MSG_LOAD_START = 1;
     private static final int MSG_LOAD_FINISH = 2;
     private static final int MSG_RUN_OBJECT = 3;

     public static interface DataListener {
         public void onContentChanged(int index);
         public void onSizeChanged(int size);
     }

     private final MediaSet[] mData;
     private final MediaItem[] mCoverItem;
     private final int[] mTotalCount;
     private final long[] mItemVersion;
     private final long[] mSetVersion;

     private int mActiveStart = 0;
     private int mActiveEnd = 0;

     private int mContentStart = 0;
     private int mContentEnd = 0;

     private final MediaSet mSource;
     private long mSourceVersion = MediaObject.INVALID_DATA_VERSION;
     private int mSize;

     private DataListener mDataListener;
     private LoadingListener mLoadingListener;
     private ReloadTask mReloadTask;

     private final Handler mMainHandler;

     private final MySourceListener mSourceListener = new MySourceListener();

     public AlbumSetDataLoader(AbstractGalleryActivity activity, MediaSet albumSet, int cacheSize) {
         mSource = Utils.checkNotNull(albumSet);
         mCoverItem = new MediaItem[cacheSize];
         mData = new MediaSet[cacheSize];
         mTotalCount = new int[cacheSize];
         mItemVersion = new long[cacheSize];
         mSetVersion = new long[cacheSize];
         Arrays.fill(mItemVersion, MediaObject.INVALID_DATA_VERSION);
         Arrays.fill(mSetVersion, MediaObject.INVALID_DATA_VERSION);

         mMainHandler = new SynchronizedHandler(activity.getGLRoot()) {
             @Override
             public void handleMessage(Message message) {
                 switch (message.what) {
                     case MSG_RUN_OBJECT:
                         ((Runnable) message.obj).run();
                         return;
                     case MSG_LOAD_START:
                         if (mLoadingListener != null) mLoadingListener.onLoadingStarted();
                         return;
                     case MSG_LOAD_FINISH:
                         if (mLoadingListener != null) mLoadingListener.onLoadingFinished(false);
                         return;
                 }
             }
         };
     }

     public void pause() {
         mReloadTask.terminate();
         mReloadTask = null;
         mSource.removeContentListener(mSourceListener);
     }

     public void resume() {
         mSource.addContentListener(mSourceListener);
         mReloadTask = new ReloadTask();
         mReloadTask.start();
     }

     private void assertIsActive(int index) {
         if (index < mActiveStart && index >= mActiveEnd) {
             throw new IllegalArgumentException(String.format(
                     "%s not in (%s, %s)", index, mActiveStart, mActiveEnd));
         }
     }

     public MediaSet getMediaSet(int index) {
         assertIsActive(index);
         return mData[index % mData.length];
     }

     public MediaItem getCoverItem(int index) {
         assertIsActive(index);
         return mCoverItem[index % mCoverItem.length];
     }

     public int getTotalCount(int index) {
         assertIsActive(index);
         return mTotalCount[index % mTotalCount.length];
     }

     public int getActiveStart() {
         return mActiveStart;
     }

     public boolean isActive(int index) {
         return index >= mActiveStart && index < mActiveEnd;
     }

     public int size() {
         return mSize;
     }

     // Returns the index of the MediaSet with the given path or
     // -1 if the path is not cached
     public int findSet(Path id) {
         int length = mData.length;
         for (int i = mContentStart; i < mContentEnd; i++) {
             MediaSet set = mData[i % length];
             if (set != null && id == set.getPath()) {
                 return i;
             }
         }
         return -1;
     }

     private void clearSlot(int slotIndex) {
         mData[slotIndex] = null;
         mCoverItem[slotIndex] = null;
         mTotalCount[slotIndex] = 0;
         mItemVersion[slotIndex] = MediaObject.INVALID_DATA_VERSION;
         mSetVersion[slotIndex] = MediaObject.INVALID_DATA_VERSION;
     }

     private void setContentWindow(int contentStart, int contentEnd) {
         if (contentStart == mContentStart && contentEnd == mContentEnd) return;
         int length = mCoverItem.length;

         int start = this.mContentStart;
         int end = this.mContentEnd;

         mContentStart = contentStart;
         mContentEnd = contentEnd;

         if (contentStart >= end || start >= contentEnd) {
             for (int i = start, n = end; i < n; ++i) {
                 clearSlot(i % length);
             }
         } else {
             for (int i = start; i < contentStart; ++i) {
                 clearSlot(i % length);
             }
             for (int i = contentEnd, n = end; i < n; ++i) {
                 clearSlot(i % length);
             }
         }
         mReloadTask.notifyDirty();
     }

     public void setActiveWindow(int start, int end) {
         if (start == mActiveStart && end == mActiveEnd) return;

         Utils.assertTrue(start <= end
                 && end - start <= mCoverItem.length && end <= mSize);

         mActiveStart = start;
         mActiveEnd = end;

         int length = mCoverItem.length;
         // If no data is visible, keep the cache content
         if (start == end) return;

         int contentStart = Utils.clamp((start + end) / 2 - length / 2,
                 0, Math.max(0, mSize - length));
         int contentEnd = Math.min(contentStart + length, mSize);
         if (mContentStart > start || mContentEnd < end
                 || Math.abs(contentStart - mContentStart) > MIN_LOAD_COUNT) {
             setContentWindow(contentStart, contentEnd);
         }
     }

     private class MySourceListener implements ContentListener {
         @Override
         public void onContentDirty() {
             mReloadTask.notifyDirty();
         }
     }

     public void setModelListener(DataListener listener) {
         mDataListener = listener;
     }

     public void setLoadingListener(LoadingListener listener) {
         mLoadingListener = listener;
     }

     private static class UpdateInfo {
         public long version;
         public int index;

         public int size;
         public MediaSet item;
         public MediaItem cover;
         public int totalCount;
     }

     private class GetUpdateInfo implements Callable<UpdateInfo> {

         private final long mVersion;

         public GetUpdateInfo(long version) {
             mVersion = version;
         }

         private int getInvalidIndex(long version) {
             long setVersion[] = mSetVersion;
             int length = setVersion.length;
             for (int i = mContentStart, n = mContentEnd; i < n; ++i) {
                 int index = i % length;
                 if (setVersion[i % length] != version) return i;
             }
             return INDEX_NONE;
         }

         @Override
         public UpdateInfo call() throws Exception {
             int index = getInvalidIndex(mVersion);
             if (index == INDEX_NONE && mSourceVersion == mVersion) return null;
             UpdateInfo info = new UpdateInfo();
             info.version = mSourceVersion;
             info.index = index;
             info.size = mSize;
             return info;
         }
     }

     private class UpdateContent implements Callable<Void> {
         private final UpdateInfo mUpdateInfo;

         public UpdateContent(UpdateInfo info) {
             mUpdateInfo = info;
         }

         @Override
         public Void call() {
             // Avoid notifying listeners of status change after pause
             // Otherwise gallery will be in inconsistent state after resume.
             if (mReloadTask == null) return null;
             UpdateInfo info = mUpdateInfo;
             mSourceVersion = info.version;
             if (mSize != info.size) {
                 mSize = info.size;
                 if (mDataListener != null) mDataListener.onSizeChanged(mSize);
                 if (mContentEnd > mSize) mContentEnd = mSize;
                 if (mActiveEnd > mSize) mActiveEnd = mSize;
             }
             // Note: info.index could be INDEX_NONE, i.e., -1
             if (info.index >= mContentStart && info.index < mContentEnd) {
                 int pos = info.index % mCoverItem.length;
                 mSetVersion[pos] = info.version;
                 long itemVersion = info.item.getDataVersion();
                 if (mItemVersion[pos] == itemVersion) return null;
                 mItemVersion[pos] = itemVersion;
                 mData[pos] = info.item;
                 mCoverItem[pos] = info.cover;
                 mTotalCount[pos] = info.totalCount;
                 if (mDataListener != null
                         && info.index >= mActiveStart && info.index < mActiveEnd) {
                     mDataListener.onContentChanged(info.index);
                 }
             }
             return null;
         }
     }

     private <T> T executeAndWait(Callable<T> callable) {
         FutureTask<T> task = new FutureTask<T>(callable);
         mMainHandler.sendMessage(
                 mMainHandler.obtainMessage(MSG_RUN_OBJECT, task));
         try {
             return task.get();
         } catch (InterruptedException e) {
             return null;
         } catch (ExecutionException e) {
             throw new RuntimeException(e);
         }
     }

     // TODO: load active range first
     private class ReloadTask extends Thread {
         private volatile boolean mActive = true;
         private volatile boolean mDirty = true;
         private volatile boolean mIsLoading = false;

         private void updateLoading(boolean loading) {
             if (mIsLoading == loading) return;
             mIsLoading = loading;
             mMainHandler.sendEmptyMessage(loading ? MSG_LOAD_START : MSG_LOAD_FINISH);
         }

         @Override
         public void run() {
             Process.setThreadPriority(Process.THREAD_PRIORITY_BACKGROUND);

             boolean updateComplete = false;
             while (mActive) {
                 synchronized (this) {
                     if (mActive && !mDirty && updateComplete) {
                         if (!mSource.isLoading()) updateLoading(false);
                         Utils.waitWithoutInterrupt(this);
                         continue;
                     }
                 }
                 mDirty = false;
                 updateLoading(true);

                 long version = mSource.reload();
                 UpdateInfo info = executeAndWait(new GetUpdateInfo(version));
                 updateComplete = info == null;
                 if (updateComplete) continue;
                 if (info.version != version) {
                     info.version = version;
                     info.size = mSource.getSubMediaSetCount();

                     // If the size becomes smaller after reload(), we may
                     // receive from GetUpdateInfo an index which is too
                     // big. Because the main thread is not aware of the size
                     // change until we call UpdateContent.
                     if (info.index >= info.size) {
                         info.index = INDEX_NONE;
                     }
                 }
                 if (info.index != INDEX_NONE) {
                     info.item = mSource.getSubMediaSet(info.index);
                     if (info.item == null) continue;
                     info.cover = info.item.getCoverMediaItem();
                     info.totalCount = info.item.getTotalMediaItemCount();
                 }
                 executeAndWait(new UpdateContent(info));
             }
             updateLoading(false);
         }

         public synchronized void notifyDirty() {
             mDirty = true;
             notifyAll();
         }

         public synchronized void terminate() {
             mActive = false;
             notifyAll();
         }
     }
 }
	/*
	* Copyright (C) 2010 The Android Open Source Project
	*
	* Licensed 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
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	package com.android.gallery3d.app;

	import android.os.Handler;
	import android.os.Message;
	import android.os.Process;

	import com.android.gallery3d.common.Utils;
	import com.android.gallery3d.data.ContentListener;
	import com.android.gallery3d.data.MediaItem;
	import com.android.gallery3d.data.MediaObject;
	import com.android.gallery3d.data.MediaSet;
	import com.android.gallery3d.data.Path;
	import com.android.gallery3d.ui.SynchronizedHandler;

	import java.util.Arrays;
	import java.util.concurrent.Callable;
	import java.util.concurrent.ExecutionException;
	import java.util.concurrent.FutureTask;

	public class AlbumSetDataLoader {
	@SuppressWarnings("unused")
	private static final String TAG = "AlbumSetDataAdapter";

	private static final int INDEX_NONE = -1;

	private static final int MIN_LOAD_COUNT = 4;

	private static final int MSG_LOAD_START = 1;
	private static final int MSG_LOAD_FINISH = 2;
	private static final int MSG_RUN_OBJECT = 3;

	public static interface DataListener {
	public void onContentChanged(int index);
	public void onSizeChanged(int size);
	}

	private final MediaSet[] mData;
	private final MediaItem[] mCoverItem;
	private final int[] mTotalCount;
	private final long[] mItemVersion;
	private final long[] mSetVersion;

	private int mActiveStart = 0;
	private int mActiveEnd = 0;

	private int mContentStart = 0;
	private int mContentEnd = 0;

	private final MediaSet mSource;
	private long mSourceVersion = MediaObject.INVALID_DATA_VERSION;
	private int mSize;

	private DataListener mDataListener;
	private LoadingListener mLoadingListener;
	private ReloadTask mReloadTask;

	private final Handler mMainHandler;

	private final MySourceListener mSourceListener = new MySourceListener();

	public AlbumSetDataLoader(AbstractGalleryActivity activity, MediaSet albumSet, int cacheSize) {
	mSource = Utils.checkNotNull(albumSet);
	mCoverItem = new MediaItem[cacheSize];
	mData = new MediaSet[cacheSize];
	mTotalCount = new int[cacheSize];
	mItemVersion = new long[cacheSize];
	mSetVersion = new long[cacheSize];
	Arrays.fill(mItemVersion, MediaObject.INVALID_DATA_VERSION);
	Arrays.fill(mSetVersion, MediaObject.INVALID_DATA_VERSION);

	mMainHandler = new SynchronizedHandler(activity.getGLRoot()) {
	@Override
	public void handleMessage(Message message) {
	switch (message.what) {
	case MSG_RUN_OBJECT:
	((Runnable) message.obj).run();
	return;
	case MSG_LOAD_START:
	if (mLoadingListener != null) mLoadingListener.onLoadingStarted();
	return;
	case MSG_LOAD_FINISH:
	if (mLoadingListener != null) mLoadingListener.onLoadingFinished(false);
	return;
	}
	}
	};
	}

	public void pause() {
	mReloadTask.terminate();
	mReloadTask = null;
	mSource.removeContentListener(mSourceListener);
	}

	public void resume() {
	mSource.addContentListener(mSourceListener);
	mReloadTask = new ReloadTask();
	mReloadTask.start();
	}

	private void assertIsActive(int index) {
	if (index < mActiveStart && index >= mActiveEnd) {
	throw new IllegalArgumentException(String.format(
	"%s not in (%s, %s)", index, mActiveStart, mActiveEnd));
	}
	}

	public MediaSet getMediaSet(int index) {
	assertIsActive(index);
	return mData[index % mData.length];
	}

	public MediaItem getCoverItem(int index) {
	assertIsActive(index);
	return mCoverItem[index % mCoverItem.length];
	}

	public int getTotalCount(int index) {
	assertIsActive(index);
	return mTotalCount[index % mTotalCount.length];
	}

	public int getActiveStart() {
	return mActiveStart;
	}

	public boolean isActive(int index) {
	return index >= mActiveStart && index < mActiveEnd;
	}

	public int size() {
	return mSize;
	}

	// Returns the index of the MediaSet with the given path or
	// -1 if the path is not cached
	public int findSet(Path id) {
	int length = mData.length;
	for (int i = mContentStart; i < mContentEnd; i++) {
	MediaSet set = mData[i % length];
	if (set != null && id == set.getPath()) {
	return i;
	}
	}
	return -1;
	}

	private void clearSlot(int slotIndex) {
	mData[slotIndex] = null;
	mCoverItem[slotIndex] = null;
	mTotalCount[slotIndex] = 0;
	mItemVersion[slotIndex] = MediaObject.INVALID_DATA_VERSION;
	mSetVersion[slotIndex] = MediaObject.INVALID_DATA_VERSION;
	}

	private void setContentWindow(int contentStart, int contentEnd) {
	if (contentStart == mContentStart && contentEnd == mContentEnd) return;
	int length = mCoverItem.length;

	int start = this.mContentStart;
	int end = this.mContentEnd;

	mContentStart = contentStart;
	mContentEnd = contentEnd;

	if (contentStart >= end \|\| start >= contentEnd) {
	for (int i = start, n = end; i < n; ++i) {
	clearSlot(i % length);
	}
	} else {
	for (int i = start; i < contentStart; ++i) {
	clearSlot(i % length);
	}
	for (int i = contentEnd, n = end; i < n; ++i) {
	clearSlot(i % length);
	}
	}
	mReloadTask.notifyDirty();
	}

	public void setActiveWindow(int start, int end) {
	if (start == mActiveStart && end == mActiveEnd) return;

	Utils.assertTrue(start <= end
	&& end - start <= mCoverItem.length && end <= mSize);

	mActiveStart = start;
	mActiveEnd = end;

	int length = mCoverItem.length;
	// If no data is visible, keep the cache content
	if (start == end) return;

	int contentStart = Utils.clamp((start + end) / 2 - length / 2,
	0, Math.max(0, mSize - length));
	int contentEnd = Math.min(contentStart + length, mSize);
	if (mContentStart > start \|\| mContentEnd < end
	\|\| Math.abs(contentStart - mContentStart) > MIN_LOAD_COUNT) {
	setContentWindow(contentStart, contentEnd);
	}
	}

	private class MySourceListener implements ContentListener {
	@Override
	public void onContentDirty() {
	mReloadTask.notifyDirty();
	}
	}

	public void setModelListener(DataListener listener) {
	mDataListener = listener;
	}

	public void setLoadingListener(LoadingListener listener) {
	mLoadingListener = listener;
	}

	private static class UpdateInfo {
	public long version;
	public int index;

	public int size;
	public MediaSet item;
	public MediaItem cover;
	public int totalCount;
	}

	private class GetUpdateInfo implements Callable<UpdateInfo> {

	private final long mVersion;

	public GetUpdateInfo(long version) {
	mVersion = version;
	}

	private int getInvalidIndex(long version) {
	long setVersion[] = mSetVersion;
	int length = setVersion.length;
	for (int i = mContentStart, n = mContentEnd; i < n; ++i) {
	int index = i % length;
	if (setVersion[i % length] != version) return i;
	}
	return INDEX_NONE;
	}

	@Override
	public UpdateInfo call() throws Exception {
	int index = getInvalidIndex(mVersion);
	if (index == INDEX_NONE && mSourceVersion == mVersion) return null;
	UpdateInfo info = new UpdateInfo();
	info.version = mSourceVersion;
	info.index = index;
	info.size = mSize;
	return info;
	}
	}

	private class UpdateContent implements Callable<Void> {
	private final UpdateInfo mUpdateInfo;

	public UpdateContent(UpdateInfo info) {
	mUpdateInfo = info;
	}

	@Override
	public Void call() {
	// Avoid notifying listeners of status change after pause
	// Otherwise gallery will be in inconsistent state after resume.
	if (mReloadTask == null) return null;
	UpdateInfo info = mUpdateInfo;
	mSourceVersion = info.version;
	if (mSize != info.size) {
	mSize = info.size;
	if (mDataListener != null) mDataListener.onSizeChanged(mSize);
	if (mContentEnd > mSize) mContentEnd = mSize;
	if (mActiveEnd > mSize) mActiveEnd = mSize;
	}
	// Note: info.index could be INDEX_NONE, i.e., -1
	if (info.index >= mContentStart && info.index < mContentEnd) {
	int pos = info.index % mCoverItem.length;
	mSetVersion[pos] = info.version;
	long itemVersion = info.item.getDataVersion();
	if (mItemVersion[pos] == itemVersion) return null;
	mItemVersion[pos] = itemVersion;
	mData[pos] = info.item;
	mCoverItem[pos] = info.cover;
	mTotalCount[pos] = info.totalCount;
	if (mDataListener != null
	&& info.index >= mActiveStart && info.index < mActiveEnd) {
	mDataListener.onContentChanged(info.index);
	}
	}
	return null;
	}
	}

	private <T> T executeAndWait(Callable<T> callable) {
	FutureTask<T> task = new FutureTask<T>(callable);
	mMainHandler.sendMessage(
	mMainHandler.obtainMessage(MSG_RUN_OBJECT, task));
	try {
	return task.get();
	} catch (InterruptedException e) {
	return null;
	} catch (ExecutionException e) {
	throw new RuntimeException(e);
	}
	}

	// TODO: load active range first
	private class ReloadTask extends Thread {
	private volatile boolean mActive = true;
	private volatile boolean mDirty = true;
	private volatile boolean mIsLoading = false;

	private void updateLoading(boolean loading) {
	if (mIsLoading == loading) return;
	mIsLoading = loading;
	mMainHandler.sendEmptyMessage(loading ? MSG_LOAD_START : MSG_LOAD_FINISH);
	}

	@Override
	public void run() {
	Process.setThreadPriority(Process.THREAD_PRIORITY_BACKGROUND);

	boolean updateComplete = false;
	while (mActive) {
	synchronized (this) {
	if (mActive && !mDirty && updateComplete) {
	if (!mSource.isLoading()) updateLoading(false);
	Utils.waitWithoutInterrupt(this);
	continue;
	}
	}
	mDirty = false;
	updateLoading(true);

	long version = mSource.reload();
	UpdateInfo info = executeAndWait(new GetUpdateInfo(version));
	updateComplete = info == null;
	if (updateComplete) continue;
	if (info.version != version) {
	info.version = version;
	info.size = mSource.getSubMediaSetCount();

	// If the size becomes smaller after reload(), we may
	// receive from GetUpdateInfo an index which is too
	// big. Because the main thread is not aware of the size
	// change until we call UpdateContent.
	if (info.index >= info.size) {
	info.index = INDEX_NONE;
	}
	}
	if (info.index != INDEX_NONE) {
	info.item = mSource.getSubMediaSet(info.index);
	if (info.item == null) continue;
	info.cover = info.item.getCoverMediaItem();
	info.totalCount = info.item.getTotalMediaItemCount();
	}
	executeAndWait(new UpdateContent(info));
	}
	updateLoading(false);
	}

	public synchronized void notifyDirty() {
	mDirty = true;
	notifyAll();
	}

	public synchronized void terminate() {
	mActive = false;
	notifyAll();
	}
	}
	}