Fix off-by-one error storing offline content

The final chunk was only being stored when the endTime of the final
segment happened to be null.  An index with explicit end times for
all segments, even on one stream, would trigger this bug.

For example, the end time of the final video segment may be null, but
the end time of the final audio segment may be equal to the content
duration.  The stored audio would be missing a chunk, causing the
computed stream limit to be too short on playback.

This corrects the off-by-one error in the storage code by explicitly
signalling when a segment is the last one, rather than checking for
a null endTime.

Closes #157

Change-Id: Ic99d53b9e2b071409d4d9472b8bc4ae0cf76f940

lib/util/content_database_writer.js

@@ -317,8 +317,10 @@ shaka.util.ContentDatabaseWriter.prototype.insertStreamContent_ = function(
 
   for (var i = 0; i < segmentIndex.length(); ++i) {
     var reference = segmentIndex.get(i);
+    var isLast = (i == segmentIndex.length() - 1);
     var requestSegment = this.requestSegment_.bind(this, reference);
-    var appendSegment = this.appendSegment_.bind(this, reference, state);
+    var appendSegment = this.appendSegment_.bind(this, reference, state,
+                                                 isLast);
     segmentPromise = segmentPromise.then(requestSegment);
     segmentPromise = segmentPromise.then(appendSegment);
   }
@@ -342,12 +344,13 @@ shaka.util.ContentDatabaseWriter.prototype.insertStreamContent_ = function(
  *   current segment.
  * @param {shaka.util.ContentDatabaseWriter.InsertStreamState} state The state
  *     of the current stream being inserted.
+ * @param {boolean} isLast True for the last segment in a stream.
  * @param {!ArrayBuffer} segment The current segment of the stream.
  * @return {!Promise}
  * @private
  */
 shaka.util.ContentDatabaseWriter.prototype.appendSegment_ = function(
-    ref, state, segment) {
+    ref, state, isLast, segment) {
   var p = new shaka.util.PublicPromise();
 
   if (state.segment.byteLength == 0) {
@@ -361,8 +364,7 @@ shaka.util.ContentDatabaseWriter.prototype.appendSegment_ = function(
         detail: percent,
         bubbles: true });
   var size = state.segment.byteLength;
-  if (size >= shaka.util.ContentDatabaseWriter.TARGET_SEGMENT_SIZE_ ||
-      ref.endTime == null) {
+  if (size >= shaka.util.ContentDatabaseWriter.TARGET_SEGMENT_SIZE_ || isLast) {
     var data = {
       'stream_id': state.streamId,
       'segment_id': state.segmentId,

spec/content_database_spec.js

@@ -203,6 +203,30 @@ describe('ContentDatabase', function() {
         });
       });
 
+  // Bug #157:
+  it('stores a stream with an explicit end time', function(done) {
+    var references = [
+      new shaka.media.SegmentReference(0, 100, createFailover(url))
+    ];
+    var index = new shaka.media.SegmentIndex(references);
+    streamInfo.segmentIndexSource = {
+      create: function() { return Promise.resolve(index); }
+    };
+    p.then(function() {
+      return writer.insertStream_(streamInfo, index, testInitData, 1, 0);
+    }).then(function(streamId) {
+      return reader.retrieveStreamIndex(streamId);
+    }).then(function(streamIndex) {
+      expect(streamIndex.references.length).toEqual(1);
+      expect(streamIndex.references[0]).toMatchReference(
+          { start_time: 0, end_time: 100 });
+      done();
+    }).catch(function(err) {
+      fail(err);
+      done();
+    });
+  });
+
   it('throws an error when trying to store an invalid stream', function(done) {
     p.then(function() {
       return writer.insertStream_(null, null, null, 0, 0);