Synchronously change to next state from downloading state

PiperOrigin-RevId: 231586206

library/core/src/main/java/com/google/android/exoplayer2/offline/DownloadManager.java

@@ -310,9 +310,10 @@ public final class DownloadManager {
   /** Returns whether there are no active downloads. */
   public boolean isIdle() {
     Assertions.checkState(!released);
-    if (!initialized) {
+    if (!initialized || !activeDownloads.isEmpty()) {
       return false;
     }
+    // Still need to check all downloads as there might be remove tasks going on.
     for (int i = 0; i < downloads.size(); i++) {
       if (!downloads.get(i).isIdle()) {
         return false;
@@ -365,6 +366,14 @@ public final class DownloadManager {
     }
   }
 
+  private void maybeRestartDownload(Download download) {
+    if (activeDownloads.contains(download)) {
+      download.start();
+    } else {
+      maybeStartDownload(download);
+    }
+  }
+
   private void maybeNotifyListenersIdle() {
     if (!isIdle()) {
       return;
@@ -540,7 +549,7 @@ public final class DownloadManager {
       this.startTimeMs = System.currentTimeMillis();
       actionQueue = new ArrayDeque<>();
       actionQueue.add(action);
-      initialize(/* restart= */ false);
+      initialize();
     }
 
     public boolean addAction(DownloadAction newAction) {
@@ -562,12 +571,12 @@ public final class DownloadManager {
           setState(STATE_REMOVING);
         }
       } else if (!action.equals(updatedAction)) {
+        Assertions.checkState(
+            state == STATE_DOWNLOADING || state == STATE_QUEUED || state == STATE_STOPPED);
         if (state == STATE_DOWNLOADING) {
           stopDownloadThread();
-        } else {
-          Assertions.checkState(state == STATE_QUEUED || state == STATE_STOPPED);
-          initialize(/* restart= */ false);
         }
+        initialize();
       }
       return true;
     }
@@ -633,13 +642,14 @@ public final class DownloadManager {
     public void updateStopFlags(int flags, int values) {
       stopFlags = (values & flags) | (stopFlags & ~flags);
       if (stopFlags != 0) {
-        if (state == STATE_DOWNLOADING) {
-          stopDownloadThread();
-        } else if (state == STATE_QUEUED) {
+        if (state == STATE_DOWNLOADING || state == STATE_QUEUED) {
+          if (state == STATE_DOWNLOADING) {
+            stopDownloadThread();
+          }
           setState(STATE_STOPPED);
         }
       } else if (state == STATE_STOPPED) {
-        startOrQueue(/* restart= */ false);
+        startOrQueue();
       }
     }
 
@@ -650,7 +660,7 @@ public final class DownloadManager {
           notMetRequirements != 0 ? STOP_FLAG_REQUIREMENTS_NOT_MET : 0);
     }
 
-    private void initialize(boolean restart) {
+    private void initialize() {
       DownloadAction action = actionQueue.peek();
       if (action.isRemoveAction) {
         if (!downloadManager.released) {
@@ -660,18 +670,14 @@ public final class DownloadManager {
       } else if (stopFlags != 0) {
         setState(STATE_STOPPED);
       } else {
-        startOrQueue(restart);
+        startOrQueue();
       }
     }
 
-    private void startOrQueue(boolean restart) {
+    private void startOrQueue() {
       // Set to queued state but don't notify listeners until we make sure we can't start now.
       state = STATE_QUEUED;
-      if (restart) {
-        start();
-      } else {
-        downloadManager.maybeStartDownload(this);
-      }
+      downloadManager.maybeRestartDownload(this);
       if (state == STATE_QUEUED) {
         downloadManager.onDownloadStateChange(this);
       }
@@ -683,6 +689,9 @@ public final class DownloadManager {
     }
 
     private void startDownloadThread(DownloadAction action) {
+      if (downloadThread != null) {
+        return;
+      }
       downloader = downloaderFactory.createDownloader(action);
       downloadThread =
           new DownloadThread(
@@ -690,29 +699,37 @@ public final class DownloadManager {
     }
 
     private void stopDownloadThread() {
-      Assertions.checkNotNull(downloadThread).cancel();
+      if (!downloadThread.isRemoveThread) {
+        Assertions.checkNotNull(downloadThread).cancel();
+      }
     }
 
-    private void onDownloadThreadStopped(@Nullable Throwable finalError) {
+    private void onDownloadThreadStopped(@Nullable Throwable error) {
       failureReason = FAILURE_REASON_NONE;
-      if (!downloadThread.isCanceled) {
-        if (finalError != null && state != STATE_REMOVING && state != STATE_RESTARTING) {
-          failureReason = FAILURE_REASON_UNKNOWN;
-          setState(STATE_FAILED);
-          return;
+      boolean isCanceled = downloadThread.isCanceled;
+      downloadThread = null;
+      if (isCanceled) {
+        if (!isIdle()) {
+          startDownloadThread(actionQueue.peek());
         }
-        if (actionQueue.size() == 1) {
-          if (state == STATE_REMOVING) {
-            setState(STATE_REMOVED);
-          } else {
-            Assertions.checkState(state == STATE_DOWNLOADING);
-            setState(STATE_COMPLETED);
-          }
-          return;
-        }
-        actionQueue.remove();
+        return;
       }
-      initialize(/* restart= */ state == STATE_DOWNLOADING);
+      if (error != null && state == STATE_DOWNLOADING) {
+        failureReason = FAILURE_REASON_UNKNOWN;
+        setState(STATE_FAILED);
+        return;
+      }
+      if (actionQueue.size() == 1) {
+        if (state == STATE_REMOVING) {
+          setState(STATE_REMOVED);
+        } else {
+          Assertions.checkState(state == STATE_DOWNLOADING);
+          setState(STATE_COMPLETED);
+        }
+        return;
+      }
+      actionQueue.remove();
+      initialize();
     }
   }
 
@@ -720,7 +737,7 @@ public final class DownloadManager {
 
     private final Download download;
     private final Downloader downloader;
-    private final boolean remove;
+    private final boolean isRemoveThread;
     private final int minRetryCount;
     private final Handler callbackHandler;
     private final Thread thread;
@@ -729,12 +746,12 @@ public final class DownloadManager {
     private DownloadThread(
         Download download,
         Downloader downloader,
-        boolean remove,
+        boolean isRemoveThread,
         int minRetryCount,
         Handler callbackHandler) {
       this.download = download;
       this.downloader = downloader;
-      this.remove = remove;
+      this.isRemoveThread = isRemoveThread;
       this.minRetryCount = minRetryCount;
       this.callbackHandler = callbackHandler;
       thread = new Thread(this);
@@ -754,7 +771,7 @@ public final class DownloadManager {
       logd("Download is started", download);
       Throwable error = null;
       try {
-        if (remove) {
+        if (isRemoveThread) {
           downloader.remove();
         } else {
           int errorCount = 0;

library/core/src/main/java/com/google/android/exoplayer2/offline/DownloadState.java

@@ -182,13 +182,11 @@ public final class DownloadState {
       byte[] customMetadata) {
     Assertions.checkState(
         failureReason == FAILURE_REASON_NONE ? state != STATE_FAILED : state == STATE_FAILED);
+    Assertions.checkState(stopFlags == 0 || (state != STATE_DOWNLOADING && state != STATE_QUEUED));
     Assertions.checkState(
         (stopFlags & STOP_FLAG_REQUIREMENTS_NOT_MET) == 0
             ? notMetRequirements == 0
             : notMetRequirements != 0);
-    // TODO enable this when we start changing state immediately
-    // Assertions.checkState(stopFlags == 0 || (state != STATE_DOWNLOADING && state !=
-    // STATE_QUEUED));
     this.id = id;
     this.type = type;
     this.uri = uri;

library/dash/src/test/java/com/google/android/exoplayer2/source/dash/offline/DownloadManagerDashTest.java

@@ -53,6 +53,7 @@ import org.mockito.MockitoAnnotations;
 import org.robolectric.RobolectricTestRunner;
 import org.robolectric.RuntimeEnvironment;
 import org.robolectric.annotation.Config;
+import org.robolectric.shadows.ShadowLog;
 
 /** Tests {@link DownloadManager}. */
 @RunWith(RobolectricTestRunner.class)
@@ -73,6 +74,7 @@ public class DownloadManagerDashTest {
 
   @Before
   public void setUp() throws Exception {
+    ShadowLog.stream = System.out;
     dummyMainThread = new DummyMainThread();
     Context context = RuntimeEnvironment.application;
     tempFolder = Util.createTempDirectory(context, "ExoPlayerTest");