Rename DownloadThread to Task

This resolves some naming confusion that previously existed
as a result of DownloadThread also being used for removals.
Some related variables (e.g. activeDownloadCount) would refer
to both download and removal tasks, whilst others
(e.g. maxParallelDownloads) would refer only to downloads.
This change renames those that refer to both to use "task"
terminology.

This change also includes minor test edits.

PiperOrigin-RevId: 245913671

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

@@ -137,7 +137,7 @@ public final class DownloadManager {
   private static final int MSG_SET_MIN_RETRY_COUNT = 5;
   private static final int MSG_ADD_DOWNLOAD = 6;
   private static final int MSG_REMOVE_DOWNLOAD = 7;
-  private static final int MSG_DOWNLOAD_THREAD_STOPPED = 8;
+  private static final int MSG_TASK_STOPPED = 8;
   private static final int MSG_CONTENT_LENGTH_CHANGED = 9;
   private static final int MSG_RELEASE = 10;
 
@@ -168,7 +168,7 @@ public final class DownloadManager {
   private final ArrayList<Download> downloads;
 
   private int pendingMessages;
-  private int activeDownloadCount;
+  private int activeTaskCount;
   private boolean initialized;
   private boolean downloadsPaused;
   private int maxParallelDownloads;
@@ -244,7 +244,7 @@ public final class DownloadManager {
    * download requirements are not met).
    */
   public boolean isIdle() {
-    return activeDownloadCount == 0 && pendingMessages == 0;
+    return activeTaskCount == 0 && pendingMessages == 0;
   }
 
   /**
@@ -465,7 +465,7 @@ public final class DownloadManager {
       mainHandler.removeCallbacksAndMessages(/* token= */ null);
       // Reset state.
       pendingMessages = 0;
-      activeDownloadCount = 0;
+      activeTaskCount = 0;
       initialized = false;
       downloads.clear();
     }
@@ -503,8 +503,8 @@ public final class DownloadManager {
         break;
       case MSG_PROCESSED:
         int processedMessageCount = message.arg1;
-        int activeDownloadCount = message.arg2;
-        onMessageProcessed(processedMessageCount, activeDownloadCount);
+        int activeTaskCount = message.arg2;
+        onMessageProcessed(processedMessageCount, activeTaskCount);
         break;
       default:
         throw new IllegalStateException();
@@ -543,9 +543,9 @@ public final class DownloadManager {
     }
   }
 
-  private void onMessageProcessed(int processedMessageCount, int activeDownloadCount) {
+  private void onMessageProcessed(int processedMessageCount, int activeTaskCount) {
     this.pendingMessages -= processedMessageCount;
-    this.activeDownloadCount = activeDownloadCount;
+    this.activeTaskCount = activeTaskCount;
     if (isIdle()) {
       for (Listener listener : listeners) {
         listener.onIdle(this);
@@ -627,7 +627,7 @@ public final class DownloadManager {
     private final DownloaderFactory downloaderFactory;
     private final Handler mainHandler;
     private final ArrayList<DownloadInternal> downloadInternals;
-    private final HashMap<String, DownloadThread> downloadThreads;
+    private final HashMap<String, Task> activeTasks;
 
     // Mutable fields that are accessed on the internal thread.
     @Requirements.RequirementFlags private int notMetRequirements;
@@ -653,7 +653,7 @@ public final class DownloadManager {
       this.minRetryCount = minRetryCount;
       this.downloadsPaused = downloadsPaused;
       downloadInternals = new ArrayList<>();
-      downloadThreads = new HashMap<>();
+      activeTasks = new HashMap<>();
     }
 
     @Override
@@ -694,14 +694,14 @@ public final class DownloadManager {
           id = (String) message.obj;
           removeDownload(id);
           break;
-        case MSG_DOWNLOAD_THREAD_STOPPED:
-          DownloadThread downloadThread = (DownloadThread) message.obj;
-          onDownloadThreadStopped(downloadThread);
+        case MSG_TASK_STOPPED:
+          Task task = (Task) message.obj;
+          onTaskStopped(task);
           processedExternalMessage = false; // This message is posted internally.
           break;
         case MSG_CONTENT_LENGTH_CHANGED:
-          downloadThread = (DownloadThread) message.obj;
-          onDownloadThreadContentLengthChanged(downloadThread);
+          task = (Task) message.obj;
+          onContentLengthChanged(task);
           processedExternalMessage = false; // This message is posted internally.
           break;
         case MSG_RELEASE:
@@ -711,7 +711,7 @@ public final class DownloadManager {
           throw new IllegalStateException();
       }
       mainHandler
-          .obtainMessage(MSG_PROCESSED, processedExternalMessage ? 1 : 0, downloadThreads.size())
+          .obtainMessage(MSG_PROCESSED, processedExternalMessage ? 1 : 0, activeTasks.size())
           .sendToTarget();
     }
 
@@ -832,18 +832,17 @@ public final class DownloadManager {
       }
     }
 
-    private void onDownloadThreadStopped(DownloadThread downloadThread) {
-      logd("Download is stopped", downloadThread.request);
-      String downloadId = downloadThread.request.id;
-      downloadThreads.remove(downloadId);
+    private void onTaskStopped(Task task) {
+      logd("Task is stopped", task.request);
+      String downloadId = task.request.id;
+      activeTasks.remove(downloadId);
       boolean tryToStartDownloads = false;
-      if (!downloadThread.isRemove) {
+      if (!task.isRemove) {
         // If maxParallelDownloads was hit, there might be a download waiting for a slot.
         tryToStartDownloads = parallelDownloads == maxParallelDownloads;
         parallelDownloads--;
       }
-      getDownload(downloadId)
-          .onDownloadThreadStopped(downloadThread.isCanceled, downloadThread.finalError);
+      getDownload(downloadId).onTaskStopped(task.isCanceled, task.finalError);
       if (tryToStartDownloads) {
         for (int i = 0;
             parallelDownloads < maxParallelDownloads && i < downloadInternals.size();
@@ -853,16 +852,16 @@ public final class DownloadManager {
       }
     }
 
-    private void onDownloadThreadContentLengthChanged(DownloadThread downloadThread) {
-      String downloadId = downloadThread.request.id;
-      getDownload(downloadId).setContentLength(downloadThread.contentLength);
+    private void onContentLengthChanged(Task task) {
+      String downloadId = task.request.id;
+      getDownload(downloadId).setContentLength(task.contentLength);
     }
 
     private void release() {
-      for (DownloadThread downloadThread : downloadThreads.values()) {
-        downloadThread.cancel(/* released= */ true);
+      for (Task task : activeTasks.values()) {
+        task.cancel(/* released= */ true);
       }
-      downloadThreads.clear();
+      activeTasks.clear();
       downloadInternals.clear();
       thread.quit();
       synchronized (this) {
@@ -871,7 +870,7 @@ public final class DownloadManager {
       }
     }
 
-    private void onDownloadChangedInternal(DownloadInternal downloadInternal, Download download) {
+    private void onDownloadChanged(DownloadInternal downloadInternal, Download download) {
       logd("Download state is changed", downloadInternal);
       try {
         downloadIndex.putDownload(download);
@@ -884,7 +883,7 @@ public final class DownloadManager {
       mainHandler.obtainMessage(MSG_DOWNLOAD_CHANGED, download).sendToTarget();
     }
 
-    private void onDownloadRemovedInternal(DownloadInternal downloadInternal, Download download) {
+    private void onDownloadRemoved(DownloadInternal downloadInternal, Download download) {
       logd("Download is removed", downloadInternal);
       try {
         downloadIndex.removeDownload(download.request.id);
@@ -896,11 +895,11 @@ public final class DownloadManager {
     }
 
     @StartThreadResults
-    private int startDownloadThread(DownloadInternal downloadInternal) {
+    private int startTask(DownloadInternal downloadInternal) {
       DownloadRequest request = downloadInternal.download.request;
       String downloadId = request.id;
-      if (downloadThreads.containsKey(downloadId)) {
-        if (stopDownloadThreadInternal(downloadId)) {
+      if (activeTasks.containsKey(downloadId)) {
+        if (stopDownloadTask(downloadId)) {
           return START_THREAD_WAIT_DOWNLOAD_CANCELLATION;
         }
         return START_THREAD_WAIT_REMOVAL_TO_FINISH;
@@ -914,19 +913,25 @@ public final class DownloadManager {
       }
       Downloader downloader = downloaderFactory.createDownloader(request);
       DownloadProgress downloadProgress = downloadInternal.download.progress;
-      DownloadThread downloadThread =
-          new DownloadThread(request, downloader, downloadProgress, isRemove, minRetryCount, this);
-      downloadThreads.put(downloadId, downloadThread);
-      downloadThread.start();
-      logd("Download is started", downloadInternal);
+      Task task =
+          new Task(
+              request,
+              downloader,
+              downloadProgress,
+              isRemove,
+              minRetryCount,
+              /* internalHandler= */ this);
+      activeTasks.put(downloadId, task);
+      task.start();
+      logd("Task is started", downloadInternal);
       return START_THREAD_SUCCEEDED;
     }
 
-    private boolean stopDownloadThreadInternal(String downloadId) {
-      DownloadThread downloadThread = downloadThreads.get(downloadId);
-      if (downloadThread != null && !downloadThread.isRemove) {
-        downloadThread.cancel(/* released= */ false);
-        logd("Download is cancelled", downloadThread.request);
+    private boolean stopDownloadTask(String downloadId) {
+      Task task = activeTasks.get(downloadId);
+      if (task != null && !task.isRemove) {
+        task.cancel(/* released= */ false);
+        logd("Task is cancelled", task.request);
         return true;
       }
       return false;
@@ -1025,7 +1030,7 @@ public final class DownloadManager {
       if (state == STATE_QUEUED || state == STATE_DOWNLOADING) {
         startOrQueue();
       } else if (isInRemoveState()) {
-        internalHandler.startDownloadThread(this);
+        internalHandler.startTask(this);
       }
     }
 
@@ -1043,7 +1048,7 @@ public final class DownloadManager {
         return;
       }
       this.contentLength = contentLength;
-      internalHandler.onDownloadChangedInternal(this, getUpdatedDownload());
+      internalHandler.onDownloadChanged(this, getUpdatedDownload());
     }
 
     private void updateStopState() {
@@ -1054,12 +1059,12 @@ public final class DownloadManager {
         }
       } else {
         if (state == STATE_DOWNLOADING || state == STATE_QUEUED) {
-          internalHandler.stopDownloadThreadInternal(download.request.id);
+          internalHandler.stopDownloadTask(download.request.id);
           setState(STATE_STOPPED);
         }
       }
       if (oldDownload == download) {
-        internalHandler.onDownloadChangedInternal(this, getUpdatedDownload());
+        internalHandler.onDownloadChanged(this, getUpdatedDownload());
       }
     }
 
@@ -1068,14 +1073,14 @@ public final class DownloadManager {
       // state immediately.
       state = initialState;
       if (isInRemoveState()) {
-        internalHandler.startDownloadThread(this);
+        internalHandler.startTask(this);
       } else if (canStart()) {
         startOrQueue();
       } else {
         setState(STATE_STOPPED);
       }
       if (state == initialState) {
-        internalHandler.onDownloadChangedInternal(this, getUpdatedDownload());
+        internalHandler.onDownloadChanged(this, getUpdatedDownload());
       }
     }
 
@@ -1085,7 +1090,7 @@ public final class DownloadManager {
 
     private void startOrQueue() {
       Assertions.checkState(!isInRemoveState());
-      @StartThreadResults int result = internalHandler.startDownloadThread(this);
+      @StartThreadResults int result = internalHandler.startTask(this);
       Assertions.checkState(result != START_THREAD_WAIT_REMOVAL_TO_FINISH);
       if (result == START_THREAD_SUCCEEDED || result == START_THREAD_WAIT_DOWNLOAD_CANCELLATION) {
         setState(STATE_DOWNLOADING);
@@ -1097,18 +1102,18 @@ public final class DownloadManager {
     private void setState(@Download.State int newState) {
       if (state != newState) {
         state = newState;
-        internalHandler.onDownloadChangedInternal(this, getUpdatedDownload());
+        internalHandler.onDownloadChanged(this, getUpdatedDownload());
       }
     }
 
-    private void onDownloadThreadStopped(boolean isCanceled, @Nullable Throwable error) {
+    private void onTaskStopped(boolean isCanceled, @Nullable Throwable error) {
       if (isIdle()) {
         return;
       }
       if (isCanceled) {
-        internalHandler.startDownloadThread(this);
+        internalHandler.startTask(this);
       } else if (state == STATE_REMOVING) {
-        internalHandler.onDownloadRemovedInternal(this, getUpdatedDownload());
+        internalHandler.onDownloadRemoved(this, getUpdatedDownload());
       } else if (state == STATE_RESTARTING) {
         initialize(STATE_QUEUED);
       } else { // STATE_DOWNLOADING
@@ -1123,7 +1128,7 @@ public final class DownloadManager {
     }
   }
 
-  private static class DownloadThread extends Thread implements Downloader.ProgressListener {
+  private static class Task extends Thread implements Downloader.ProgressListener {
 
     private final DownloadRequest request;
     private final Downloader downloader;
@@ -1137,7 +1142,7 @@ public final class DownloadManager {
 
     private long contentLength;
 
-    private DownloadThread(
+    private Task(
         DownloadRequest request,
         Downloader downloader,
         DownloadProgress downloadProgress,
@@ -1203,7 +1208,7 @@ public final class DownloadManager {
       }
       Handler internalHandler = this.internalHandler;
       if (internalHandler != null) {
-        internalHandler.obtainMessage(MSG_DOWNLOAD_THREAD_STOPPED, this).sendToTarget();
+        internalHandler.obtainMessage(MSG_TASK_STOPPED, this).sendToTarget();
       }
     }
 

library/core/src/test/java/com/google/android/exoplayer2/offline/DownloadBuilder.java

@@ -40,7 +40,7 @@ import java.util.List;
   @Nullable private String cacheKey;
   private byte[] customMetadata;
 
-  private int state;
+  @Download.State private int state;
   private long startTimeMs;
   private long updateTimeMs;
   private long contentLength;
@@ -111,7 +111,7 @@ import java.util.List;
     return this;
   }
 
-  public DownloadBuilder setState(int state) {
+  public DownloadBuilder setState(@Download.State int state) {
     this.state = state;
     return this;
   }

library/core/src/test/java/com/google/android/exoplayer2/offline/DownloadManagerTest.java

@@ -359,7 +359,7 @@ public class DownloadManagerTest {
   }
 
   @Test
-  public void stopAndResume() throws Throwable {
+  public void pauseAndResume() throws Throwable {
     DownloadRunner runner1 = new DownloadRunner(uri1);
     DownloadRunner runner2 = new DownloadRunner(uri2);
     DownloadRunner runner3 = new DownloadRunner(uri3);
@@ -370,10 +370,12 @@ public class DownloadManagerTest {
 
     runOnMainThread(() -> downloadManager.pauseDownloads());
 
+    // TODO: This should be assertQueued. Fix implementation and update test.
     runner1.getTask().assertStopped();
 
     // remove requests aren't stopped.
     runner2.getDownloader(1).unblock().assertReleased();
+    // TODO: This should be assertQueued. Fix implementation and update test.
     runner2.getTask().assertStopped();
     // Although remove2 is finished, download2 doesn't start.
     runner2.getDownloader(2).assertDoesNotStart();