Support setReadTimeout in CronetHttpURLConnection

components/cronet/android/java/src/org/chromium/net/urlconnection/MessageLoop.java

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 package org.chromium.net.urlconnection;
 
 import java.io.IOException;
+import java.io.InterruptedIOException;
+import java.net.SocketTimeoutException;
 import java.util.concurrent.BlockingQueue;
 import java.util.concurrent.Executor;
 import java.util.concurrent.LinkedBlockingQueue;
 import java.util.concurrent.RejectedExecutionException;
+import java.util.concurrent.TimeUnit;
 
 /**
  * A MessageLoop class for use in {@link CronetHttpURLConnection}.
  */
 class MessageLoop implements Executor {
     private final BlockingQueue<Runnable> mQueue;
 
     // Indicates whether this message loop is currently running.
     private boolean mLoopRunning = false;
 
@@ skipping 13 matching lines @@
 
     private boolean calledOnValidThread() {
         if (mThreadId == INVALID_THREAD_ID) {
             mThreadId = Thread.currentThread().getId();
             return true;
         }
         return mThreadId == Thread.currentThread().getId();
     }
 
     /**
+     * Retrieves a task from the queue with the given timeout.
+     *
+     * @param useTimeout whether to use a timeout.
+     * @param timeout Time to wait, in milliseconds.
+     * @return A non-{@code null} Runnable from the queue.
+     * @throws InterruptedIOException
+     */
+    private Runnable take(boolean useTimeout, int timeout) throws InterruptedIOException {

[kapishnikov, 2016/05/18 01:13:42]

Should we change the timeout type in this method to long in order to avoid the
long to int conversion?

[xunjieli, 2016/05/18 13:31:27]

Done.

+        Runnable task = null;
+        try {
+            if (!useTimeout) {
+                task = mQueue.take(); // Blocks if the queue is empty.
+            } else {
+                // poll returns null upon timeout.
+                task = mQueue.poll(timeout, TimeUnit.MILLISECONDS);
+            }
+        } catch (InterruptedException e) {
+            InterruptedIOException exception = new InterruptedIOException();
+            exception.initCause(e);
+            throw exception;
+        }
+        if (task == null) {
+            // This will terminate the loop.
+            throw new SocketTimeoutException();
+        }
+        return task;
+    }
+
+    /**
      * Runs the message loop. Be sure to call {@link MessageLoop#quit()}
      * to end the loop. If an interruptedException occurs, the loop cannot be
      * started again (see {@link #mLoopFailed}).
      * @throws IOException
      */
     public void loop() throws IOException {
+        loop(0);
+    }
+
+    /**
+     * Runs the message loop. Be sure to call {@link MessageLoop#quit()}
+     * to end the loop. If an interruptedException occurs, the loop cannot be
+     * started again (see {@link #mLoopFailed}).
+     * @param timeout Timeout, in milliseconds, or 0 for no timeout.
+     * @throws IOException
+     */
+    public void loop(int timeout) throws IOException {
         assert calledOnValidThread();
+        long start = System.currentTimeMillis();

[kapishnikov, 2016/05/18 01:13:43]

It is better to use System.nanoTime(), which returns a monotonically increasing
value and ignores system clock adjustments.

[xunjieli, 2016/05/18 13:31:27]

Done.

         if (mLoopFailed) {
             throw new IllegalStateException(
                     "Cannot run loop as an exception has occurred previously.");
         }
         if (mLoopRunning) {
             throw new IllegalStateException(
                     "Cannot run loop when it is already running.");
         }
         mLoopRunning = true;
         while (mLoopRunning) {
             try {
-                Runnable task = mQueue.take(); // Blocks if the queue is empty.
-                task.run();
-            } catch (InterruptedException | RuntimeException e) {
+                if (timeout == 0) {
+                    take(false, timeout);

[kapishnikov, 2016/05/18 01:13:42]

Better take(false, 0)

[xunjieli, 2016/05/18 13:31:27]

Done.

+                } else {
+                    long timeElapsed = System.currentTimeMillis() - start;
+                    // Make sure overflow won't happen when casting timeElapsed to an int.
+                    if (timeElapsed > timeout) {
+                        throw new SocketTimeoutException();
+                    }
+                    // Will system clock run backwards?
+                    if (timeElapsed < 0) {

[kapishnikov, 2016/05/18 01:13:42]

This should not be possible with System.nanoTime().

[xunjieli, 2016/05/18 13:31:27]

Done.

+                        timeElapsed = 0;
+                    }
+                    take(true, timeout - (int) timeElapsed).run();
+                }
+            } catch (InterruptedIOException | RuntimeException e) {
                 mLoopRunning = false;
                 mLoopFailed = true;
-                if (e instanceof InterruptedException) {
-                    throw new IOException(e);
-                } else if (e instanceof RuntimeException) {
-                    throw (RuntimeException) e;
-                }
+                throw e;
             }
         }
     }
 
     /**
      * This causes {@link #loop()} to stop executing messages after the current
      * message being executed.  Should only be called from the currently
      * executing message.
      */
     public void quit() {
@@ skipping 25 matching lines @@
         return mLoopRunning;
     }
 
     /**
      * Returns whether an exception occurred in {#loop()}. Used in testing.
      */
     public boolean hasLoopFailed() {
         return mLoopFailed;
     }
 }