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Diffstat (limited to 'src/main/java/com/android/volley/AsyncRequestQueue.java')
| -rw-r--r-- | src/main/java/com/android/volley/AsyncRequestQueue.java | 626 |
1 files changed, 626 insertions, 0 deletions
diff --git a/src/main/java/com/android/volley/AsyncRequestQueue.java b/src/main/java/com/android/volley/AsyncRequestQueue.java new file mode 100644 index 0000000..3754866 --- /dev/null +++ b/src/main/java/com/android/volley/AsyncRequestQueue.java @@ -0,0 +1,626 @@ +/* + * Copyright (C) 2020 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.volley; + +import android.os.Handler; +import android.os.Looper; +import android.os.SystemClock; +import androidx.annotation.NonNull; +import androidx.annotation.Nullable; +import com.android.volley.AsyncCache.OnGetCompleteCallback; +import com.android.volley.AsyncNetwork.OnRequestComplete; +import com.android.volley.Cache.Entry; +import java.net.HttpURLConnection; +import java.util.Comparator; +import java.util.concurrent.BlockingQueue; +import java.util.concurrent.CountDownLatch; +import java.util.concurrent.ExecutorService; +import java.util.concurrent.Executors; +import java.util.concurrent.PriorityBlockingQueue; +import java.util.concurrent.ScheduledExecutorService; +import java.util.concurrent.ScheduledThreadPoolExecutor; +import java.util.concurrent.ThreadFactory; +import java.util.concurrent.ThreadPoolExecutor; +import java.util.concurrent.TimeUnit; + +/** + * An asynchronous request dispatch queue. + * + * <p>Add requests to the queue with {@link #add(Request)}. Once completed, responses will be + * delivered on the main thread (unless a custom {@link ResponseDelivery} has been provided) + */ +public class AsyncRequestQueue extends RequestQueue { + /** Default number of blocking threads to start. */ + private static final int DEFAULT_BLOCKING_THREAD_POOL_SIZE = 4; + + /** + * AsyncCache used to retrieve and store responses. + * + * <p>{@code null} indicates use of blocking Cache. + */ + @Nullable private final AsyncCache mAsyncCache; + + /** AsyncNetwork used to perform nework requests. */ + private final AsyncNetwork mNetwork; + + /** Executor for non-blocking tasks. */ + private ExecutorService mNonBlockingExecutor; + + /** Executor to be used for non-blocking tasks that need to be scheduled. */ + private ScheduledExecutorService mNonBlockingScheduledExecutor; + + /** + * Executor for blocking tasks. + * + * <p>Some tasks in handling requests may not be easy to implement in a non-blocking way, such + * as reading or parsing the response data. This executor is used to run these tasks. + */ + private ExecutorService mBlockingExecutor; + + /** + * This interface may be used by advanced applications to provide custom executors according to + * their needs. Apps must create ExecutorServices dynamically given a blocking queue rather than + * providing them directly so that Volley can provide a PriorityQueue which will prioritize + * requests according to Request#getPriority. + */ + private ExecutorFactory mExecutorFactory; + + /** Manage list of waiting requests and de-duplicate requests with same cache key. */ + private final WaitingRequestManager mWaitingRequestManager = new WaitingRequestManager(this); + + /** + * Sets all the variables, but processing does not begin until {@link #start()} is called. + * + * @param cache to use for persisting responses to disk. If an AsyncCache was provided, then + * this will be a {@link ThrowingCache} + * @param network to perform HTTP requests + * @param asyncCache to use for persisting responses to disk. May be null to indicate use of + * blocking cache + * @param responseDelivery interface for posting responses and errors + * @param executorFactory Interface to be used to provide custom executors according to the + * users needs. + */ + private AsyncRequestQueue( + Cache cache, + AsyncNetwork network, + @Nullable AsyncCache asyncCache, + ResponseDelivery responseDelivery, + ExecutorFactory executorFactory) { + super(cache, network, /* threadPoolSize= */ 0, responseDelivery); + mAsyncCache = asyncCache; + mNetwork = network; + mExecutorFactory = executorFactory; + } + + /** Sets the executors and initializes the cache. */ + @Override + public void start() { + stop(); // Make sure any currently running threads are stopped + + // Create blocking / non-blocking executors and set them in the network and stack. + mNonBlockingExecutor = mExecutorFactory.createNonBlockingExecutor(getBlockingQueue()); + mBlockingExecutor = mExecutorFactory.createBlockingExecutor(getBlockingQueue()); + mNonBlockingScheduledExecutor = mExecutorFactory.createNonBlockingScheduledExecutor(); + mNetwork.setBlockingExecutor(mBlockingExecutor); + mNetwork.setNonBlockingExecutor(mNonBlockingExecutor); + mNetwork.setNonBlockingScheduledExecutor(mNonBlockingScheduledExecutor); + + mNonBlockingExecutor.execute( + new Runnable() { + @Override + public void run() { + // This is intentionally blocking, because we don't want to process any + // requests until the cache is initialized. + if (mAsyncCache != null) { + final CountDownLatch latch = new CountDownLatch(1); + mAsyncCache.initialize( + new AsyncCache.OnWriteCompleteCallback() { + @Override + public void onWriteComplete() { + latch.countDown(); + } + }); + try { + latch.await(); + } catch (InterruptedException e) { + VolleyLog.e( + e, "Thread was interrupted while initializing the cache."); + Thread.currentThread().interrupt(); + throw new RuntimeException(e); + } + } else { + getCache().initialize(); + } + } + }); + } + + /** Shuts down and nullifies both executors */ + @Override + public void stop() { + if (mNonBlockingExecutor != null) { + mNonBlockingExecutor.shutdownNow(); + mNonBlockingExecutor = null; + } + if (mBlockingExecutor != null) { + mBlockingExecutor.shutdownNow(); + mBlockingExecutor = null; + } + if (mNonBlockingScheduledExecutor != null) { + mNonBlockingScheduledExecutor.shutdownNow(); + mNonBlockingScheduledExecutor = null; + } + } + + /** Begins the request by sending it to the Cache or Network. */ + @Override + <T> void beginRequest(Request<T> request) { + // If the request is uncacheable, send it over the network. + if (request.shouldCache()) { + if (mAsyncCache != null) { + mNonBlockingExecutor.execute(new CacheTask<>(request)); + } else { + mBlockingExecutor.execute(new CacheTask<>(request)); + } + } else { + sendRequestOverNetwork(request); + } + } + + @Override + <T> void sendRequestOverNetwork(Request<T> request) { + mNonBlockingExecutor.execute(new NetworkTask<>(request)); + } + + /** Runnable that gets an entry from the cache. */ + private class CacheTask<T> extends RequestTask<T> { + CacheTask(Request<T> request) { + super(request); + } + + @Override + public void run() { + // If the request has been canceled, don't bother dispatching it. + if (mRequest.isCanceled()) { + mRequest.finish("cache-discard-canceled"); + return; + } + + mRequest.addMarker("cache-queue-take"); + + // Attempt to retrieve this item from cache. + if (mAsyncCache != null) { + mAsyncCache.get( + mRequest.getCacheKey(), + new OnGetCompleteCallback() { + @Override + public void onGetComplete(Entry entry) { + handleEntry(entry, mRequest); + } + }); + } else { + Entry entry = getCache().get(mRequest.getCacheKey()); + handleEntry(entry, mRequest); + } + } + } + + /** Helper method that handles the cache entry after getting it from the Cache. */ + private void handleEntry(final Entry entry, final Request<?> mRequest) { + if (entry == null) { + mRequest.addMarker("cache-miss"); + // Cache miss; send off to the network dispatcher. + if (!mWaitingRequestManager.maybeAddToWaitingRequests(mRequest)) { + sendRequestOverNetwork(mRequest); + } + return; + } + + // If it is completely expired, just send it to the network. + if (entry.isExpired()) { + mRequest.addMarker("cache-hit-expired"); + mRequest.setCacheEntry(entry); + if (!mWaitingRequestManager.maybeAddToWaitingRequests(mRequest)) { + sendRequestOverNetwork(mRequest); + } + return; + } + + // We have a cache hit; parse its data for delivery back to the request. + mBlockingExecutor.execute(new CacheParseTask<>(mRequest, entry)); + } + + private class CacheParseTask<T> extends RequestTask<T> { + Cache.Entry entry; + + CacheParseTask(Request<T> request, Cache.Entry entry) { + super(request); + this.entry = entry; + } + + @Override + public void run() { + mRequest.addMarker("cache-hit"); + Response<?> response = + mRequest.parseNetworkResponse( + new NetworkResponse( + HttpURLConnection.HTTP_OK, + entry.data, + /* notModified= */ false, + /* networkTimeMs= */ 0, + entry.allResponseHeaders)); + mRequest.addMarker("cache-hit-parsed"); + + if (!entry.refreshNeeded()) { + // Completely unexpired cache hit. Just deliver the response. + getResponseDelivery().postResponse(mRequest, 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. + mRequest.addMarker("cache-hit-refresh-needed"); + mRequest.setCacheEntry(entry); + // Mark the response as intermediate. + response.intermediate = true; + + if (!mWaitingRequestManager.maybeAddToWaitingRequests(mRequest)) { + // Post the intermediate response back to the user and have + // the delivery then forward the request along to the network. + getResponseDelivery() + .postResponse( + mRequest, + response, + new Runnable() { + @Override + public void run() { + sendRequestOverNetwork(mRequest); + } + }); + } else { + // request has been added to list of waiting requests + // to receive the network response from the first request once it + // returns. + getResponseDelivery().postResponse(mRequest, response); + } + } + } + } + + private class ParseErrorTask<T> extends RequestTask<T> { + VolleyError volleyError; + + ParseErrorTask(Request<T> request, VolleyError volleyError) { + super(request); + this.volleyError = volleyError; + } + + @Override + public void run() { + VolleyError parsedError = mRequest.parseNetworkError(volleyError); + getResponseDelivery().postError(mRequest, parsedError); + mRequest.notifyListenerResponseNotUsable(); + } + } + + /** Runnable that performs the network request */ + private class NetworkTask<T> extends RequestTask<T> { + NetworkTask(Request<T> request) { + super(request); + } + + @Override + public void run() { + // If the request was cancelled already, do not perform the network request. + if (mRequest.isCanceled()) { + mRequest.finish("network-discard-cancelled"); + mRequest.notifyListenerResponseNotUsable(); + return; + } + + final long startTimeMs = SystemClock.elapsedRealtime(); + mRequest.addMarker("network-queue-take"); + + // TODO: Figure out what to do with traffic stats tags. Can this be pushed to the + // HTTP stack, or is it no longer feasible to support? + + // Perform the network request. + mNetwork.performRequest( + mRequest, + new OnRequestComplete() { + @Override + public void onSuccess(final NetworkResponse networkResponse) { + mRequest.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 && mRequest.hasHadResponseDelivered()) { + mRequest.finish("not-modified"); + mRequest.notifyListenerResponseNotUsable(); + return; + } + + // Parse the response here on the worker thread. + mBlockingExecutor.execute( + new NetworkParseTask<>(mRequest, networkResponse)); + } + + @Override + public void onError(final VolleyError volleyError) { + volleyError.setNetworkTimeMs( + SystemClock.elapsedRealtime() - startTimeMs); + mBlockingExecutor.execute(new ParseErrorTask<>(mRequest, volleyError)); + } + }); + } + } + + /** Runnable that parses a network response. */ + private class NetworkParseTask<T> extends RequestTask<T> { + NetworkResponse networkResponse; + + NetworkParseTask(Request<T> request, NetworkResponse networkResponse) { + super(request); + this.networkResponse = networkResponse; + } + + @Override + public void run() { + final Response<?> response = mRequest.parseNetworkResponse(networkResponse); + mRequest.addMarker("network-parse-complete"); + + // Write to cache if applicable. + // TODO: Only update cache metadata instead of entire + // record for 304s. + if (mRequest.shouldCache() && response.cacheEntry != null) { + if (mAsyncCache != null) { + mNonBlockingExecutor.execute(new CachePutTask<>(mRequest, response)); + } else { + mBlockingExecutor.execute(new CachePutTask<>(mRequest, response)); + } + } else { + finishRequest(mRequest, response, /* cached= */ false); + } + } + } + + private class CachePutTask<T> extends RequestTask<T> { + Response<?> response; + + CachePutTask(Request<T> request, Response<?> response) { + super(request); + this.response = response; + } + + @Override + public void run() { + if (mAsyncCache != null) { + mAsyncCache.put( + mRequest.getCacheKey(), + response.cacheEntry, + new AsyncCache.OnWriteCompleteCallback() { + @Override + public void onWriteComplete() { + finishRequest(mRequest, response, /* cached= */ true); + } + }); + } else { + getCache().put(mRequest.getCacheKey(), response.cacheEntry); + finishRequest(mRequest, response, /* cached= */ true); + } + } + } + + /** Posts response and notifies listener */ + private void finishRequest(Request<?> mRequest, Response<?> response, boolean cached) { + if (cached) { + mRequest.addMarker("network-cache-written"); + } + // Post the response back. + mRequest.markDelivered(); + getResponseDelivery().postResponse(mRequest, response); + mRequest.notifyListenerResponseReceived(response); + } + + /** + * This class may be used by advanced applications to provide custom executors according to + * their needs. Apps must create ExecutorServices dynamically given a blocking queue rather than + * providing them directly so that Volley can provide a PriorityQueue which will prioritize + * requests according to Request#getPriority. + */ + public abstract static class ExecutorFactory { + abstract ExecutorService createNonBlockingExecutor(BlockingQueue<Runnable> taskQueue); + + abstract ExecutorService createBlockingExecutor(BlockingQueue<Runnable> taskQueue); + + abstract ScheduledExecutorService createNonBlockingScheduledExecutor(); + } + + /** Provides a BlockingQueue to be used to create executors. */ + private static PriorityBlockingQueue<Runnable> getBlockingQueue() { + return new PriorityBlockingQueue<>( + /* initialCapacity= */ 11, + new Comparator<Runnable>() { + @Override + public int compare(Runnable r1, Runnable r2) { + // Vanilla runnables are prioritized first, then RequestTasks are ordered + // by the underlying Request. + if (r1 instanceof RequestTask) { + if (r2 instanceof RequestTask) { + return ((RequestTask<?>) r1).compareTo(((RequestTask<?>) r2)); + } + return 1; + } + return r2 instanceof RequestTask ? -1 : 0; + } + }); + } + + /** + * Builder is used to build an instance of {@link AsyncRequestQueue} from values configured by + * the setters. + */ + public static class Builder { + @Nullable private AsyncCache mAsyncCache = null; + private final AsyncNetwork mNetwork; + @Nullable private Cache mCache = null; + @Nullable private ExecutorFactory mExecutorFactory = null; + @Nullable private ResponseDelivery mResponseDelivery = null; + + public Builder(AsyncNetwork asyncNetwork) { + if (asyncNetwork == null) { + throw new IllegalArgumentException("Network cannot be null"); + } + mNetwork = asyncNetwork; + } + + /** + * Sets the executor factory to be used by the AsyncRequestQueue. If this is not called, + * Volley will create suitable private thread pools. + */ + public Builder setExecutorFactory(ExecutorFactory executorFactory) { + mExecutorFactory = executorFactory; + return this; + } + + /** + * Sets the response deliver to be used by the AsyncRequestQueue. If this is not called, we + * will default to creating a new {@link ExecutorDelivery} with the application's main + * thread. + */ + public Builder setResponseDelivery(ResponseDelivery responseDelivery) { + mResponseDelivery = responseDelivery; + return this; + } + + /** Sets the AsyncCache to be used by the AsyncRequestQueue. */ + public Builder setAsyncCache(AsyncCache asyncCache) { + mAsyncCache = asyncCache; + return this; + } + + /** Sets the Cache to be used by the AsyncRequestQueue. */ + public Builder setCache(Cache cache) { + mCache = cache; + return this; + } + + /** Provides a default ExecutorFactory to use, if one is never set. */ + private ExecutorFactory getDefaultExecutorFactory() { + return new ExecutorFactory() { + @Override + public ExecutorService createNonBlockingExecutor( + BlockingQueue<Runnable> taskQueue) { + return getNewThreadPoolExecutor( + /* maximumPoolSize= */ 1, + /* threadNameSuffix= */ "Non-BlockingExecutor", + taskQueue); + } + + @Override + public ExecutorService createBlockingExecutor(BlockingQueue<Runnable> taskQueue) { + return getNewThreadPoolExecutor( + /* maximumPoolSize= */ DEFAULT_BLOCKING_THREAD_POOL_SIZE, + /* threadNameSuffix= */ "BlockingExecutor", + taskQueue); + } + + @Override + public ScheduledExecutorService createNonBlockingScheduledExecutor() { + return new ScheduledThreadPoolExecutor( + /* corePoolSize= */ 0, getThreadFactory("ScheduledExecutor")); + } + + private ThreadPoolExecutor getNewThreadPoolExecutor( + int maximumPoolSize, + final String threadNameSuffix, + BlockingQueue<Runnable> taskQueue) { + return new ThreadPoolExecutor( + /* corePoolSize= */ 0, + /* maximumPoolSize= */ maximumPoolSize, + /* keepAliveTime= */ 60, + /* unit= */ TimeUnit.SECONDS, + taskQueue, + getThreadFactory(threadNameSuffix)); + } + + private ThreadFactory getThreadFactory(final String threadNameSuffix) { + return new ThreadFactory() { + @Override + public Thread newThread(@NonNull Runnable runnable) { + Thread t = Executors.defaultThreadFactory().newThread(runnable); + t.setName("Volley-" + threadNameSuffix); + return t; + } + }; + } + }; + } + + public AsyncRequestQueue build() { + // If neither cache is set by the caller, throw an illegal argument exception. + if (mCache == null && mAsyncCache == null) { + throw new IllegalArgumentException("You must set one of the cache objects"); + } + if (mCache == null) { + // if no cache is provided, we will provide one that throws + // UnsupportedOperationExceptions to pass into the parent class. + mCache = new ThrowingCache(); + } + if (mResponseDelivery == null) { + mResponseDelivery = new ExecutorDelivery(new Handler(Looper.getMainLooper())); + } + if (mExecutorFactory == null) { + mExecutorFactory = getDefaultExecutorFactory(); + } + return new AsyncRequestQueue( + mCache, mNetwork, mAsyncCache, mResponseDelivery, mExecutorFactory); + } + } + + /** A cache that throws an error if a method is called. */ + private static class ThrowingCache implements Cache { + @Override + public Entry get(String key) { + throw new UnsupportedOperationException(); + } + + @Override + public void put(String key, Entry entry) { + throw new UnsupportedOperationException(); + } + + @Override + public void initialize() { + throw new UnsupportedOperationException(); + } + + @Override + public void invalidate(String key, boolean fullExpire) { + throw new UnsupportedOperationException(); + } + + @Override + public void remove(String key) { + throw new UnsupportedOperationException(); + } + + @Override + public void clear() { + throw new UnsupportedOperationException(); + } + } +} |