/**
* Called from {@link Request#finish(String)}, indicating that processing of the given request has
* finished.
*
* <p>Releases waiting requests for <code>request.getCacheKey()</code> if <code>
* request.shouldCache()</code>.
*
* <p>(1). 首先从正在进行中请求集合mCurrentRequests中移除该请求。 (2).
* 然后查找请求等待集合mWaitingRequests中是否存在等待的请求，如果存在，则将等待队列移除，
* 并将等待队列所有的请求添加到缓存请求队列中，让缓存请求处理线程CacheDispatcher自动处理。
*/
<T> void finish(Request<T> request) {
// Remove from the set of requests currently being processed.
synchronized (mCurrentRequests) {
mCurrentRequests.remove(request);
}
synchronized (mFinishedListeners) {
for (RequestFinishedListener<T> listener : mFinishedListeners) {
listener.onRequestFinished(request);
}
}
if (request.shouldCache()) {
synchronized (mWaitingRequests) {
String cacheKey = request.getCacheKey();
Queue<Request<?>> waitingRequests = mWaitingRequests.remove(cacheKey);
if (waitingRequests != null) {
if (VolleyLog.DEBUG) {
VolleyLog.v(
"Releasing %d waiting requests for cacheKey=%s.", waitingRequests.size(), cacheKey);
}
// Process all queued up requests. They won't be considered as in flight, but
// that's not a problem as the cache has been primed by 'request'.
mCacheQueue.addAll(waitingRequests);
}
}
}
}
@Before
public void setUp() throws Exception {
initMocks(this);
dispatcher = new SyncDispatcher(cache, mockNetwork);
Response response = Response.success(null, cacheEntry);
when(cache.get(anyString())).thenReturn(cacheEntry);
when(request.parseNetworkResponse(any(NetworkResponse.class))).thenReturn(response);
when(request.getCacheKey()).thenReturn("test-cache-key");
}
/**
* Adds a Request to the dispatch queue.
*
* @param request The request to service
* @return The passed-in request
*/
public Request add(Request request) {
// Tag the request as belonging to this queue and add it to the set of current requests.
request.setRequestQueue(this);
// Rewrite the url, in case of GET requests
if (mUrlRewriter != null) {
request.setUrl(mUrlRewriter.rewriteUrl(request));
}
synchronized (mCurrentRequests) {
mCurrentRequests.add(request);
}
// Process requests in the order they are added.
request.setSequence(getSequenceNumber());
request.addMarker("add-to-queue");
// If the request is uncacheable, skip the cache queue and go straight to the network.
if (!request.shouldCache()) {
mNetworkQueue.add(request);
return request;
}
// Insert request into stage if there's already a request with the same cache key in flight.
synchronized (mWaitingRequests) {
String cacheKey = request.getCacheKey();
if (mWaitingRequests.containsKey(cacheKey)) {
// There is already a request in flight. Queue up.
Queue<Request> stagedRequests = mWaitingRequests.get(cacheKey);
if (stagedRequests == null) {
stagedRequests = new LinkedList<Request>();
}
stagedRequests.add(request);
mWaitingRequests.put(cacheKey, stagedRequests);
if (VolleyLog.sDebug) {
VolleyLog.v("Request for cacheKey=%s is in flight, putting on hold.", cacheKey);
}
} else {
// Insert 'null' queue for this cacheKey, indicating there is now a request in
// flight.
mWaitingRequests.put(cacheKey, null);
mCacheQueue.add(request);
}
return request;
}
}
public static <T> T getCacheFile(InputBase input, Class<T> clazz) {
Cache cache = requestQueue.getCache();
Request<T> request =
new GsonRequest<T>(input.method(), input.toString(), "", clazz, null, null, null, null);
Cache.Entry entry = cache.get(request.getCacheKey());
if (entry != null) {
try {
String json = new String(entry.data, "UTF-8");
if (clazz == String.class) {
return (T) json;
}
// File类型写文件后返回file对象
else if (clazz == File.class) {
String fileName = TextUtil.md5(input.toString());
File outFile =
new File(DirectoryManager.getDirectory(DirectoryManager.DIR.DATA), fileName);
FileUtils.writeFile(outFile.getAbsolutePath(), entry.data);
return (T) outFile;
}
// 替换服务端可能返回的错误的data格式
json = json.replace("\"data\":[]", "\"data\":{}");
// 服务器返回errNo=0
if (json.matches(ERROR_NO_0_EXPRESSION)) {
T data;
JSONObject jsonObject = new JSONObject(json);
json = jsonObject.getString("data");
// 其他属于Gson请求，解析对象返回
Gson gson = GsonUtil.createBuilder();
data = (T) gson.fromJson(json, clazz);
return data;
}
// 服务器返回errNo != 0
else {
return null;
}
} catch (Exception e) {
return null;
}
}
return null;
}
@Override
public void run() {
if (DEBUG) VolleyLog.v("start new dispatcher");
Process.setThreadPriority(Process.THREAD_PRIORITY_BACKGROUND);
// Make a blocking call to initialize the cache.
if (mCache != null) mCache.initialize();
while (true) {
try {
// Get a request from the cache triage queue, blocking until
// at least one is available.
final Request request = mCacheQueue.take();
request.addMarker("cache-queue-take");
mDelivery.postPreExecute(request);
// If the request has been canceled, don't bother dispatching it.
if (request.isCanceled()) {
mDelivery.postCancel(request);
mDelivery.postFinish(request);
request.finish("cache-discard-canceled");
continue;
}
// Attempt to retrieve this item from cache.
Cache.Entry entry = mCache != null ? mCache.get(request.getCacheKey()) : null;
if (entry == null) {
request.addMarker("cache-miss");
// Cache miss; send off to the network dispatcher.
mNetworkQueue.put(request);
mDelivery.postNetworking(request);
continue;
}
// If it is completely expired, just send it to the network.
if (entry.isExpired()) {
request.addMarker("cache-hit-expired");
mNetworkQueue.put(request);
mDelivery.postNetworking(request);
continue;
}
// We have a cache hit; parse its data for delivery back to the request.
request.addMarker("cache-hit");
Response<?> response =
request.parseNetworkResponse(
new NetworkResponse(entry.data, entry.responseHeaders, entry.charset));
request.addMarker("cache-hit-parsed");
mDelivery.postUsedCache(request);
if (!entry.refreshNeeded()) {
// Completely unexpired cache hit. Just deliver the response.
mDelivery.postResponse(request, response);
} else {
// Soft-expired cache hit. We can deliver the cached response,
// but we need to also send the request to the network for
// refreshing.
request.addMarker("cache-hit-refresh-needed");
// Mark the response as intermediate.
response.intermediate = true;
// Post the intermediate response back to the user and have
// the delivery then forward the request along to the network.
mDelivery.postResponse(
request,
response,
new Runnable() {
@Override
public void run() {
try {
mNetworkQueue.put(request);
} catch (InterruptedException e) {
// Not much we can do about this.
}
}
});
}
} catch (InterruptedException e) {
// We may have been interrupted because it was time to quit.
if (mQuit) return;
}
}
}
public static <T> void removeCacheFile(InputBase input, Class<T> clazz) {
Cache cache = requestQueue.getCache();
Request<T> request =
new GsonRequest<T>(input.method(), input.toString(), "", clazz, null, null, null, null);
cache.remove(request.getCacheKey());
}
@Override
public void run() {
Process.setThreadPriority(Process.THREAD_PRIORITY_BACKGROUND);
Request request;
while (true) {
try {
// Take a request from the queue.
request = mQueue.take();
} catch (InterruptedException e) {
// We may have been interrupted because it was time to quit.
if (mQuit) {
return;
}
continue;
}
try {
request.addMarker("network-queue-take");
// If the request was cancelled already, do not perform the
// network request.
if (request.isCanceled()) {
request.finish("network-discard-cancelled");
continue;
}
// Tag the request (if API >= 14)
if (Build.VERSION.SDK_INT >= 14) {
TrafficStats.setThreadStatsTag(request.getTrafficStatsTag());
}
// Perform the network request.
NetworkResponse networkResponse = mNetwork.performRequest(request);
request.addMarker("network-http-complete");
// If the server returned 304 AND we delivered a response already,
// we're done -- don't deliver a second identical response.
if (networkResponse.notModified && request.hasHadResponseDelivered()) {
request.finish("not-modified");
continue;
}
// Parse the response here on the worker thread.
Response<?> response = request.parseNetworkResponse(networkResponse);
request.addMarker("network-parse-complete");
// Write to cache if applicable.
// TODO: Only update cache metadata instead of entire record for 304s.
if (request.shouldCache() && response.cacheEntry != null) {
mCache.put(request.getCacheKey(), response.cacheEntry);
request.addMarker("network-cache-written");
}
// Post the response back.
request.markDelivered();
mDelivery.postResponse(request, response);
} catch (VolleyError volleyError) {
parseAndDeliverNetworkError(request, volleyError);
} catch (Exception e) {
VolleyLog.e(e, "Unhandled exception %s", e.toString());
mDelivery.postError(request, new VolleyError(e));
}
}
}