Turn CacheUtil into stateful CacheWriter

- The new CacheWriter is simplified somewhat - Blocking on PriorityTaskManager.proceed is moved out of CacheWriter and into the Downloader tasks. This is because we want to shift only the caching parts of the Downloaders onto their Executors, whilst keeping the blocking parts on the main Downloader threads. Else we can end up "using" the Executor threads indefinitely whilst they're blocked. Issue: #5978 PiperOrigin-RevId: 313222923
google · May 27, 2020 · d88f5f4 · d88f5f4
1 parent a1c72c0
commit d88f5f4
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Showing 6 changed files with 422 additions and 367 deletions.
diff --git a/library/core/src/main/java/com/google/android/exoplayer2/offline/ProgressiveDownloader.java b/library/core/src/main/java/com/google/android/exoplayer2/offline/ProgressiveDownloader.java
@@ -21,18 +21,18 @@
 import com.google.android.exoplayer2.MediaItem;
 import com.google.android.exoplayer2.upstream.DataSpec;
 import com.google.android.exoplayer2.upstream.cache.CacheDataSource;
-import com.google.android.exoplayer2.upstream.cache.CacheUtil;
+import com.google.android.exoplayer2.upstream.cache.CacheWriter;
+import com.google.android.exoplayer2.upstream.cache.CacheWriter.ProgressListener;
 import com.google.android.exoplayer2.util.Assertions;
 import com.google.android.exoplayer2.util.PriorityTaskManager;
+import com.google.android.exoplayer2.util.PriorityTaskManager.PriorityTooLowException;
 import java.io.IOException;
 import java.util.concurrent.Executor;
 import java.util.concurrent.atomic.AtomicBoolean;
 
 /** A downloader for progressive media streams. */
 public final class ProgressiveDownloader implements Downloader {
 
-  private static final int BUFFER_SIZE_BYTES = 128 * 1024;
-
   private final DataSpec dataSpec;
   private final CacheDataSource dataSource;
   private final AtomicBoolean isCanceled;
@@ -104,18 +104,35 @@ public void download(@Nullable ProgressListener progressListener) throws IOExcep
     if (isCanceled.get()) {
       return;
     }
+
+    CacheWriter cacheWriter =
+        new CacheWriter(
+            dataSource,
+            dataSpec,
+            /* allowShortContent= */ false,
+            isCanceled,
+            /* temporaryBuffer= */ null,
+            progressListener == null ? null : new ProgressForwarder(progressListener));
+
     @Nullable PriorityTaskManager priorityTaskManager = dataSource.getUpstreamPriorityTaskManager();
     if (priorityTaskManager != null) {
       priorityTaskManager.add(C.PRIORITY_DOWNLOAD);
     }
     try {
-      CacheUtil.cache(
-          dataSource,
-          dataSpec,
-          progressListener == null ? null : new ProgressForwarder(progressListener),
-          isCanceled,
-          /* enableEOFException= */ true,
-          /* temporaryBuffer= */ new byte[BUFFER_SIZE_BYTES]);
+      boolean finished = false;
+      while (!finished && !isCanceled.get()) {
+        if (priorityTaskManager != null) {
+          priorityTaskManager.proceed(dataSource.getUpstreamPriority());
+        }
+        try {
+          cacheWriter.cache();
+          finished = true;
+        } catch (PriorityTooLowException e) {
+          // The next loop iteration will block until the task is able to proceed.
+        }
+      }
+    } catch (InterruptedException e) {
+      // The download was canceled.
     } finally {
       if (priorityTaskManager != null) {
         priorityTaskManager.remove(C.PRIORITY_DOWNLOAD);
@@ -137,7 +154,7 @@ public void remove() {
     dataSource.getCache().removeResource(dataSource.getCacheKeyFactory().buildCacheKey(dataSpec));
   }
 
-  private static final class ProgressForwarder implements CacheUtil.ProgressListener {
+  private static final class ProgressForwarder implements CacheWriter.ProgressListener {
 
     private final ProgressListener progressListener;
 

diff --git a/library/core/src/main/java/com/google/android/exoplayer2/offline/SegmentDownloader.java b/library/core/src/main/java/com/google/android/exoplayer2/offline/SegmentDownloader.java
@@ -28,10 +28,11 @@
 import com.google.android.exoplayer2.upstream.cache.Cache;
 import com.google.android.exoplayer2.upstream.cache.CacheDataSource;
 import com.google.android.exoplayer2.upstream.cache.CacheKeyFactory;
-import com.google.android.exoplayer2.upstream.cache.CacheUtil;
+import com.google.android.exoplayer2.upstream.cache.CacheWriter;
 import com.google.android.exoplayer2.upstream.cache.ContentMetadata;
 import com.google.android.exoplayer2.util.Assertions;
 import com.google.android.exoplayer2.util.PriorityTaskManager;
+import com.google.android.exoplayer2.util.PriorityTaskManager.PriorityTooLowException;
 import com.google.android.exoplayer2.util.Util;
 import java.io.IOException;
 import java.util.ArrayList;
@@ -175,18 +176,32 @@ public final void download(@Nullable ProgressListener progressListener) throws I
                   segmentsDownloaded)
               : null;
       byte[] temporaryBuffer = new byte[BUFFER_SIZE_BYTES];
-      for (int i = 0; i < segments.size(); i++) {
-        CacheUtil.cache(
-            dataSource,
-            segments.get(i).dataSpec,
-            progressNotifier,
-            isCanceled,
-            /* enableEOFException= */ true,
-            temporaryBuffer);
-        if (progressNotifier != null) {
-          progressNotifier.onSegmentDownloaded();
+      int segmentIndex = 0;
+      while (!isCanceled.get() && segmentIndex < segments.size()) {
+        if (priorityTaskManager != null) {
+          priorityTaskManager.proceed(dataSource.getUpstreamPriority());
+        }
+        CacheWriter cacheWriter =
+            new CacheWriter(
+                dataSource,
+                segments.get(segmentIndex).dataSpec,
+                /* allowShortContent= */ false,
+                isCanceled,
+                temporaryBuffer,
+                progressNotifier);
+        try {
+          cacheWriter.cache();
+          segmentIndex++;
+          if (progressNotifier != null) {
+            progressNotifier.onSegmentDownloaded();
+          }
+        } catch (PriorityTooLowException e) {
+          // The next loop iteration will block until the task is able to proceed, then try and
+          // download the same segment again.
         }
       }
+    } catch (InterruptedException e) {
+      // The download was canceled.
     } finally {
       if (priorityTaskManager != null) {
         priorityTaskManager.remove(C.PRIORITY_DOWNLOAD);
@@ -293,7 +308,7 @@ private static boolean canMergeSegments(DataSpec dataSpec1, DataSpec dataSpec2)
         && dataSpec1.httpRequestHeaders.equals(dataSpec2.httpRequestHeaders);
   }
 
-  private static final class ProgressNotifier implements CacheUtil.ProgressListener {
+  private static final class ProgressNotifier implements CacheWriter.ProgressListener {
 
     private final ProgressListener progressListener;