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/*
* Copyright (C) 2009 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.camera;
import android.content.ContentResolver;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.provider.MediaStore.Images;
import android.provider.MediaStore.Video;
import android.util.Log;
import java.io.FileDescriptor;
import java.util.WeakHashMap;
/**
* Provides utilities to decode bitmap, get thumbnail, and cancel the
* operations.
*
* <p>The function {@link #decodeFileDescriptor(FileDescriptor,
* BitmapFactory.Options)} is used to decode a bitmap. During decoding another
* thread can cancel it using the function {@link #cancelThreadDecoding(Thread,
* ContentResolver)} specifying the {@code Thread} which is in decoding.
*
* <p>{@code cancelThreadDecoding(Thread,ContentResolver)} is sticky until
* {@code allowThreadDecoding(Thread) } is called.
*/
public class BitmapManager {
private static final String TAG = "BitmapManager";
private static enum State {CANCEL, ALLOW}
private static class ThreadStatus {
public State mState = State.ALLOW;
public BitmapFactory.Options mOptions;
@Override
public String toString() {
String s;
if (mState == State.CANCEL) {
s = "Cancel";
} else if (mState == State.ALLOW) {
s = "Allow";
} else {
s = "?";
}
s = "thread state = " + s + ", options = " + mOptions;
return s;
}
}
private final WeakHashMap<Thread, ThreadStatus> mThreadStatus =
new WeakHashMap<Thread, ThreadStatus>();
private static BitmapManager sManager = null;
private BitmapManager() {
}
/**
* Get thread status and create one if specified.
*/
private synchronized ThreadStatus getOrCreateThreadStatus(Thread t) {
ThreadStatus status = mThreadStatus.get(t);
if (status == null) {
status = new ThreadStatus();
mThreadStatus.put(t, status);
}
return status;
}
public synchronized boolean canThreadDecoding(Thread t) {
ThreadStatus status = mThreadStatus.get(t);
if (status == null) {
// allow decoding by default
return true;
}
boolean result = (status.mState != State.CANCEL);
return result;
}
/**
* Gets the thumbnail of the given ID of the original image.
*
* <p> This method wraps around @{code getThumbnail} in {@code
* android.provider.MediaStore}. It provides the ability to cancel it.
*/
public Bitmap getThumbnail(ContentResolver cr, long origId, int kind,
BitmapFactory.Options options, boolean isVideo) {
Thread t = Thread.currentThread();
ThreadStatus status = getOrCreateThreadStatus(t);
if (!canThreadDecoding(t)) {
Log.d(TAG, "Thread " + t + " is not allowed to decode.");
return null;
}
try {
if (isVideo) {
return Video.Thumbnails.getThumbnail(cr, origId, t.getId(),
kind, null);
} else {
return Images.Thumbnails.getThumbnail(cr, origId, t.getId(),
kind, null);
}
} finally {
synchronized (status) {
status.notifyAll();
}
}
}
public static synchronized BitmapManager instance() {
if (sManager == null) {
sManager = new BitmapManager();
}
return sManager;
}
}
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