Rollback set content length and redirect URI

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=196765970

library/core/src/main/java/com/google/android/exoplayer2/upstream/cache/CacheDataSource.java

@@ -18,6 +18,7 @@ package com.google.android.exoplayer2.upstream.cache;
 import android.net.Uri;
 import android.support.annotation.IntDef;
 import android.support.annotation.Nullable;
+import android.util.Log;
 import com.google.android.exoplayer2.C;
 import com.google.android.exoplayer2.upstream.DataSink;
 import com.google.android.exoplayer2.upstream.DataSource;
@@ -51,6 +52,8 @@ public final class CacheDataSource implements DataSource {
    */
   public static final long DEFAULT_MAX_CACHE_FILE_SIZE = 2 * 1024 * 1024;
 
+  private static final String TAG = "CacheDataSource";
+
   /**
    * Flags controlling the cache's behavior.
    */
@@ -218,7 +221,7 @@ public final class CacheDataSource implements DataSource {
     try {
       key = CacheUtil.getKey(dataSpec);
       uri = dataSpec.uri;
-      actualUri = getRedirectedUriOrDefault(cache, key, /* defaultUri= */ uri);
+      actualUri = loadRedirectedUriOrReturnGivenUri(cache, key, uri);
       flags = dataSpec.flags;
       readPosition = dataSpec.position;
 
@@ -269,7 +272,7 @@ public final class CacheDataSource implements DataSource {
           bytesRemaining -= bytesRead;
         }
       } else if (currentDataSpecLengthUnset) {
-        setNoBytesRemainingAndMaybeStoreLength();
+        setBytesRemainingAndMaybeStoreLength(0);
       } else if (bytesRemaining > 0 || bytesRemaining == C.LENGTH_UNSET) {
         closeCurrentSource();
         openNextSource(false);
@@ -278,7 +281,7 @@ public final class CacheDataSource implements DataSource {
       return bytesRead;
     } catch (IOException e) {
       if (currentDataSpecLengthUnset && isCausedByPositionOutOfRange(e)) {
-        setNoBytesRemainingAndMaybeStoreLength();
+        setBytesRemainingAndMaybeStoreLength(0);
         return C.RESULT_END_OF_INPUT;
       }
       handleBeforeThrow(e);
@@ -399,38 +402,46 @@ public final class CacheDataSource implements DataSource {
     currentDataSource = nextDataSource;
     currentDataSpecLengthUnset = nextDataSpec.length == C.LENGTH_UNSET;
     long resolvedLength = nextDataSource.open(nextDataSpec);
-
-    // Update bytesRemaining, actualUri and (if writing to cache) the cache metadata.
-    ContentMetadataMutations mutations = new ContentMetadataMutations();
     if (currentDataSpecLengthUnset && resolvedLength != C.LENGTH_UNSET) {
-      bytesRemaining = resolvedLength;
-      ContentMetadataInternal.setContentLength(mutations, readPosition + bytesRemaining);
-    }
-    if (isReadingFromUpstream()) {
-      actualUri = currentDataSource.getUri();
-      boolean isRedirected = !uri.equals(actualUri);
-      if (isRedirected) {
-        ContentMetadataInternal.setRedirectedUri(mutations, actualUri);
-      } else {
-        ContentMetadataInternal.removeRedirectedUri(mutations);
-      }
+      setBytesRemainingAndMaybeStoreLength(resolvedLength);
     }
-    if (isWritingToCache()) {
-      cache.applyContentMetadataMutations(key, mutations);
+    // TODO find a way to store length and redirected uri in one metadata mutation.
+    maybeUpdateActualUriFieldAndRedirectedUriMetadata();
+  }
+
+  private void maybeUpdateActualUriFieldAndRedirectedUriMetadata() {
+    if (!isReadingFromUpstream()) {
+      return;
     }
+    actualUri = currentDataSource.getUri();
+    maybeUpdateRedirectedUriMetadata();
   }
 
-  private void setNoBytesRemainingAndMaybeStoreLength() throws IOException {
-    bytesRemaining = 0;
-    if (isWritingToCache()) {
-      cache.setContentLength(key, readPosition);
+  private void maybeUpdateRedirectedUriMetadata() {
+    if (!isWritingToCache()) {
+      return;
+    }
+    ContentMetadataMutations mutations = new ContentMetadataMutations();
+    boolean isRedirected = !uri.equals(actualUri);
+    if (isRedirected) {
+      ContentMetadataInternal.setRedirectedUri(mutations, actualUri);
+    } else {
+      ContentMetadataInternal.removeRedirectedUri(mutations);
+    }
+    try {
+      cache.applyContentMetadataMutations(key, mutations);
+    } catch (CacheException e) {
+      String message =
+          "Couldn't update redirected URI. "
+              + "This might cause relative URIs get resolved incorrectly.";
+      Log.w(TAG, message, e);
     }
   }
 
-  private static Uri getRedirectedUriOrDefault(Cache cache, String key, Uri defaultUri) {
+  private static Uri loadRedirectedUriOrReturnGivenUri(Cache cache, String key, Uri uri) {
     ContentMetadata contentMetadata = cache.getContentMetadata(key);
     Uri redirectedUri = ContentMetadataInternal.getRedirectedUri(contentMetadata);
-    return redirectedUri == null ? defaultUri : redirectedUri;
+    return redirectedUri == null ? uri : redirectedUri;
   }
 
   private static boolean isCausedByPositionOutOfRange(IOException e) {
@@ -447,6 +458,13 @@ public final class CacheDataSource implements DataSource {
     return false;
   }
 
+  private void setBytesRemainingAndMaybeStoreLength(long bytesRemaining) throws IOException {
+    this.bytesRemaining = bytesRemaining;
+    if (isWritingToCache()) {
+      cache.setContentLength(key, readPosition + bytesRemaining);
+    }
+  }
+
   private boolean isReadingFromUpstream() {
     return !isReadingFromCache();
   }