前言

正题

1.视频拖动超过已缓存部分则停止缓存线程下载

	//HttpProxyCache.java
 public void processRequest(GetRequest request, Socket socket) throws IOException, ProxyCacheException {
 OutputStream out = new BufferedOutputStream(socket.getOutputStream());
 String responseHeaders = newResponseHeaders(request);
 out.write(responseHeaders.getBytes("UTF-8"));
 long offset = request.rangeOffset;
 if (!isForceCancel && isUseCache(request)) {
 Log.i(TAG, "processRequest: responseWithCache");
 pauseCache(false);
 responseWithCache(out, offset);
 } else {
 Log.i(TAG, "processRequest: responseWithoutCache");
 pauseCache(true);
 responseWithoutCache(out, offset);
 }
 }
	
	 /**
 * 是否强制取消缓存
 */
 public void cancelCache() {
 isForceCancel = true;
 }
 private boolean isUseCache(GetRequest request) throws ProxyCacheException {
 long sourceLength = source.length();
 boolean sourceLengthKnown = sourceLength > 0;
 long cacheAvailable = cache.available();
 // do not use cache for partial requests which too far from available cache. It seems user seek video.
 long offset = request.rangeOffset;
 //如果seek只是超出少许(这里设置为2M)仍然走缓存
 return !sourceLengthKnown || !request.partial || offset <= cacheAvailable + MINI_OFFSET_CACHE;
 }
	...
	
 private void responseWithCache(OutputStream out, long offset) throws ProxyCacheException {
 byte[] buffer = new byte[DEFAULT_BUFFER_SIZE];
 int readBytes;
 try {
 while ((readBytes = read(buffer, offset, buffer.length)) != -1 && !stopped) {
 out.write(buffer, 0, readBytes);
 offset += readBytes;
 }
 out.flush();
 } catch (IOException e) {
 e.printStackTrace();
 } finally {
 try {
 out.close();
 } catch (IOException e) {
 e.printStackTrace();
 }
 }
 }

2.脱离播放器实现缓存(离线缓存)

2.1 修改FileCache.java

	//FileCache.java
 public FileCache(String downloadFilePath) throws ProxyCacheException{
 try {
 this.diskUsage = new UnlimitedDiskUsage();
 this.file = new File(downloadFilePath);
 this.dataFile = new RandomAccessFile(this.file, "rw");
 } catch (IOException e) {
 throw new ProxyCacheException("Error using file " + file + " as disc cache", e);
 }
 }

 @Override
 public synchronized void complete() throws ProxyCacheException {
 if (isCompleted()) {
 return;
 }
 close();
 String fileName;
 if (file.getName().endsWith(DOWNLOAD_TEMP_POSTFIX)) {
 //临时下载文件
 fileName = file.getName().substring(0, file.getName().length() - DOWNLOAD_TEMP_POSTFIX.length());
 } else {
 fileName = file.getName().substring(0, file.getName().length() - TEMP_POSTFIX.length());
 }
 File completedFile = new File(file.getParentFile(), fileName);
 boolean renamed = file.renameTo(completedFile);
 if (!renamed) {
 throw new ProxyCacheException("Error renaming file " + file + " to " + completedFile + " for completion!");
 }
 file = completedFile;
 try {
 dataFile = new RandomAccessFile(file, "r");
 diskUsage.touch(file);
 } catch (IOException e) {
 throw new ProxyCacheException("Error opening " + file + " as disc cache", e);
 }
 }
	
	...
	
 private boolean isTempFile(File file) {
 return file.getName().endsWith(TEMP_POSTFIX) 
 || file.getName().endsWith(DOWNLOAD_TEMP_POSTFIX);
 }

2.2 修改HttpProxyCacheServerClients

 private FileCache mCache;
 private String downloadPath=null;
 public HttpProxyCacheServerClients(String url, Config config) {
 this.url = checkNotNull(url);
 this.config = checkNotNull(config);
 this.uiCacheListener = new UiListenerHandler(url, listeners);
 }
 public void processRequest(GetRequest request, Socket socket) {
 try {
 startProcessRequest();
 clientsCount.incrementAndGet();
 proxyCache.processRequest(request, socket);
 } catch (Exception e) {
 e.printStackTrace();
 if (e instanceof ProxyCacheException){
 uiCacheListener.onCacheError(e);
 }
 } finally {
 finishProcessRequest();
 }
 }
	...
 private synchronized void startProcessRequest() throws ProxyCacheException {
 if (proxyCache == null){
 if (downloadPath==null){
 //原proxyCache
 proxyCache=newHttpProxyCache();
 }else{
 //本地已部分下载的视频文件作为缓存
 newHttpProxyCacheForDownloadFile(downloadPath);
 }
 }
 if (isCancelCache){
 proxyCache.cancelCache();
 }
 }
	......
 public void shutdown() {
 listeners.clear();
 if (proxyCache != null) {
 proxyCache.registerCacheListener(null);
 proxyCache.shutdown();
 proxyCache = null;
 }
 clientsCount.set(0);
 //清除不必要的缓存
 if (mCache != null && isCancelCache && downloadPath == null) {
 mCache.file.delete();
 }
 }
 /**
 * 生成以已部分下载的视频为基础的缓存文件
 * @param downloadFilePath
 * @return
 * @throws ProxyCacheException
 */
 private void newHttpProxyCacheForDownloadFile(String downloadFilePath) throws ProxyCacheException {
 HttpUrlSource source = new HttpUrlSource(url, config.sourceInfoStorage, config.headerInjector);
 mCache = new FileCache(downloadFilePath);
 HttpProxyCache httpProxyCache = new HttpProxyCache(source, mCache);
 httpProxyCache.registerCacheListener(uiCacheListener);
 proxyCache = httpProxyCache;
 }

3.高码率缓存,低码率不缓存

public void onPrepared(IMediaPlayer mp) {
	...
	if ( !isLocalVideo && bitrate < MINI_BITRATE_USE_CACHE
 && mCacheManager.getDownloadTempPath(mVideoUrl)==null) 
		{
 bufferPoint = -1;
 mOnBufferUpdateListener.update(this, -1);
 mCacheManager.cancelCache(mVideoUrl);
 //注意:seekTo会重新发起请求本地代理,cancelCache后将不会走缓存分支
 if (lastWatchPosition==-1){
 seekTo(1);
 }else {
 seekTo(lastWatchPosition);
 }
 }
 if (mPreparedListener != null) {
 mPreparedListener.onPrepared(this);
 }
	...
}

4.其余小修改