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/*
* 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();
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();
}
}
}