Fix more cases of downloads not being resumed

Issue: #7453
PiperOrigin-RevId: 314710328

RELEASENOTES.md

@@ -1,6 +1,6 @@
 # Release notes #
 
-### 2.11.5 (2020-06-03) ###
+### 2.11.5 (2020-06-04) ###
 
 *   Improve the smoothness of video playback immediately after starting, seeking
     or resuming a playback
@@ -17,6 +17,9 @@
 *   Fix issue in `AudioTrackPositionTracker` that could cause negative positions
     to be reported at the start of playback and immediately after seeking
     ([#7456](https://github.com/google/ExoPlayer/issues/7456).
+*   Fix further cases where downloads would sometimes not resume after their
+    network requirements are met
+    ([#7453](https://github.com/google/ExoPlayer/issues/7453).
 *   DASH:
     *   Merge trick play adaptation sets (i.e., adaptation sets marked with
         `http://dashif.org/guidelines/trickmode`) into the same `TrackGroup` as

library/core/src/main/java/com/google/android/exoplayer2/scheduler/Requirements.java

@@ -129,11 +129,9 @@ private int getNotMetNetworkRequirements(Context context) {
     }
 
     ConnectivityManager connectivityManager =
-        (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
-    NetworkInfo networkInfo = Assertions.checkNotNull(connectivityManager).getActiveNetworkInfo();
-    if (networkInfo == null
-        || !networkInfo.isConnected()
-        || !isInternetConnectivityValidated(connectivityManager)) {
+        (ConnectivityManager)
+            Assertions.checkNotNull(context.getSystemService(Context.CONNECTIVITY_SERVICE));
+    if (!isInternetConnectivityValidated(connectivityManager)) {
       return requirements & (NETWORK | NETWORK_UNMETERED);
     }
 
@@ -156,23 +154,28 @@ private boolean isDeviceCharging(Context context) {
   }
 
   private boolean isDeviceIdle(Context context) {
-    PowerManager powerManager = (PowerManager) context.getSystemService(Context.POWER_SERVICE);
+    PowerManager powerManager =
+        (PowerManager) Assertions.checkNotNull(context.getSystemService(Context.POWER_SERVICE));
     return Util.SDK_INT >= 23
         ? powerManager.isDeviceIdleMode()
         : Util.SDK_INT >= 20 ? !powerManager.isInteractive() : !powerManager.isScreenOn();
   }
 
   private static boolean isInternetConnectivityValidated(ConnectivityManager connectivityManager) {
-    // It's possible to query NetworkCapabilities from API level 23, but RequirementsWatcher only
-    // fires an event to update its Requirements when NetworkCapabilities change from API level 24.
-    // Since Requirements won't be updated, we assume connectivity is validated on API level 23.
+    // It's possible to check NetworkCapabilities.NET_CAPABILITY_VALIDATED from API level 23, but
+    // RequirementsWatcher only fires an event to re-check the requirements when NetworkCapabilities
+    // change from API level 24. We use the legacy path for API level 23 here to keep in sync.
     if (Util.SDK_INT < 24) {
-      return true;
+      // Legacy path.
+      @Nullable NetworkInfo networkInfo = connectivityManager.getActiveNetworkInfo();
+      return networkInfo != null && networkInfo.isConnected();
     }
-    Network activeNetwork = connectivityManager.getActiveNetwork();
+
+    @Nullable Network activeNetwork = connectivityManager.getActiveNetwork();
     if (activeNetwork == null) {
       return false;
     }
+    @Nullable
     NetworkCapabilities networkCapabilities =
         connectivityManager.getNetworkCapabilities(activeNetwork);
     return networkCapabilities != null

library/core/src/main/java/com/google/android/exoplayer2/scheduler/RequirementsWatcher.java

@@ -150,6 +150,23 @@ private void checkRequirements() {
     }
   }
 
+  /**
+   * Re-checks the requirements if there are network requirements that are currently not met.
+   *
+   * <p>When we receive an event that implies newly established network connectivity, we re-check
+   * the requirements by calling {@link #checkRequirements()}. This check sometimes sees that there
+   * is still no active network, meaning that any network requirements will remain not met. By
+   * calling this method when we receive other events that imply continued network connectivity, we
+   * can detect that the requirements are met once an active network does exist.
+   */
+  private void recheckNotMetNetworkRequirements() {
+    if ((notMetRequirements & (Requirements.NETWORK | Requirements.NETWORK_UNMETERED)) == 0) {
+      // No unmet network requirements to recheck.
+      return;
+    }
+    checkRequirements();
+  }
+
   private class DeviceStatusChangeReceiver extends BroadcastReceiver {
     @Override
     public void onReceive(Context context, Intent intent) {
@@ -161,17 +178,25 @@ public void onReceive(Context context, Intent intent) {
 
   @RequiresApi(24)
   private final class NetworkCallback extends ConnectivityManager.NetworkCallback {
-    boolean receivedCapabilitiesChange;
-    boolean networkValidated;
+
+    private boolean receivedCapabilitiesChange;
+    private boolean networkValidated;
 
     @Override
     public void onAvailable(Network network) {
-      onNetworkCallback();
+      postCheckRequirements();
     }
 
     @Override
     public void onLost(Network network) {
-      onNetworkCallback();
+      postCheckRequirements();
+    }
+
+    @Override
+    public void onBlockedStatusChanged(Network network, boolean blocked) {
+      if (!blocked) {
+        postRecheckNotMetNetworkRequirements();
+      }
     }
 
     @Override
@@ -181,17 +206,28 @@ public void onCapabilitiesChanged(Network network, NetworkCapabilities networkCa
       if (!receivedCapabilitiesChange || this.networkValidated != networkValidated) {
         receivedCapabilitiesChange = true;
         this.networkValidated = networkValidated;
-        onNetworkCallback();
+        postCheckRequirements();
+      } else if (networkValidated) {
+        postRecheckNotMetNetworkRequirements();
       }
     }
 
-    private void onNetworkCallback() {
+    private void postCheckRequirements() {
       handler.post(
           () -> {
             if (networkCallback != null) {
               checkRequirements();
             }
           });
     }
+
+    private void postRecheckNotMetNetworkRequirements() {
+      handler.post(
+          () -> {
+            if (networkCallback != null) {
+              recheckNotMetNetworkRequirements();
+            }
+          });
+    }
   }
 }