From adbcdb5b886738319c3818b1bf7de416b8e4d8cc Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Tor=20Erik=20Alr=C3=A6k?= <torerik@vimond.com>
Date: Mon, 18 Jul 2016 21:45:22 +1000
Subject: [PATCH] Rewrote timeline performance workaround with deferred segment
 URL construction.

---
 lib/dash/timeline_segment_index_source.js | 14 +---
 lib/util/failover_uri.js                  | 10 +--
 vimond/deferred-uri.js                    | 96 +++++++++++++++++++++++
 3 files changed, 104 insertions(+), 16 deletions(-)
 create mode 100644 vimond/deferred-uri.js

diff --git a/lib/dash/timeline_segment_index_source.js b/lib/dash/timeline_segment_index_source.js
index 4b8f4b07e8..3e75bc2f4b 100644
--- a/lib/dash/timeline_segment_index_source.js
+++ b/lib/dash/timeline_segment_index_source.js
@@ -21,6 +21,7 @@ goog.require('shaka.asserts');
 goog.require('shaka.dash.LiveSegmentIndex');
 goog.require('shaka.features');
 goog.require('shaka.log');
+goog.require('shaka.vimond.DeferredUri');
 goog.require('shaka.media.ISegmentIndexSource');
 goog.require('shaka.media.SegmentIndex');
 goog.require('shaka.media.SegmentReference');
@@ -127,19 +128,10 @@ shaka.dash.TimelineSegmentIndexSource.prototype.create = function() {
     var timeReplacement = bigStartTime ? bigStartTime.toString() : startTime;
 
     // Generate the media URL.
-    var mediaUrl = shaka.dash.MpdUtils.createFromTemplate(
+    var mediaUrl = new shaka.vimond.DeferredUri(
         this.networkCallback_, this.representation_, segmentReplacement,
-        timeReplacement, 0, null);
-    //if (bigStartTime) {
-    //  shaka.log.info('Applied big integer timecode,', mediaUrl);
-    //}
+        timeReplacement);
     
-    if (!mediaUrl) {
-      var error = new Error('Failed to generate media URL.');
-      error.type = 'dash';
-      return Promise.reject(error);
-    }
-
     // The time points within a SegmentTimeline correspond to the timestamps
     // within the media segments. So, if @presentationTimeOffset is non-zero
     // then we must offset the SegmentReferences' start and end times by PTO so
diff --git a/lib/util/failover_uri.js b/lib/util/failover_uri.js
index a6435059b4..a7c09cdf40 100644
--- a/lib/util/failover_uri.js
+++ b/lib/util/failover_uri.js
@@ -39,19 +39,19 @@ shaka.util.FailoverUri = function(callback, urls, opt_startByte, opt_endByte) {
   shaka.asserts.assert(urls);
   shaka.asserts.assert(urls.length > 0);
 
-  /** @const {!Array.<!goog.Uri>} */
+  /** @public {!Array.<!goog.Uri>} */
   this.urls = urls;
 
-  /** @const {number} */
+  /** @public {number} */
   this.startByte = opt_startByte || 0;
 
-  /** @const {?number} */
+  /** @public {?number} */
   this.endByte = opt_endByte != null ? opt_endByte : null;
 
-  /** @private {?Promise} */
+  /** @protected {?Promise} */
   this.requestPromise_ = null;
 
-  /** @private {shaka.util.AjaxRequest} */
+  /** @protected {shaka.util.AjaxRequest} */
   this.request_ = null;
 
   /** @private {shaka.util.FailoverUri.NetworkCallback} */
diff --git a/vimond/deferred-uri.js b/vimond/deferred-uri.js
new file mode 100644
index 0000000000..5bcdfa2ba0
--- /dev/null
+++ b/vimond/deferred-uri.js
@@ -0,0 +1,96 @@
+/**
+ * @license
+ * Copyright 2015 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+goog.provide('shaka.vimond.DeferredUri');
+
+goog.require('shaka.util.FailoverUri');
+goog.require('goog.Uri');
+goog.require('shaka.asserts');
+goog.require('shaka.log');
+goog.require('shaka.util.AjaxRequest');
+
+
+
+/**
+ * Creates a FailoverUri, which handles requests to multiple URLs in case of
+ * failure.
+ *
+ * @param {shaka.util.FailoverUri.NetworkCallback} callback
+ * @param {!shaka.dash.mpd.Representation} representation
+ * @param {number} segmentReplacement
+ * @param {number} timeReplacement
+ * @extends {shaka.util.FailoverUri}
+ * @constructor
+ */
+shaka.vimond.DeferredUri = function(callback, representation, segmentReplacement, timeReplacement) {
+    
+    /** @private {!shaka.dash.mpd.Representation} */
+    this.representation_ = representation;
+
+    /** @const {number} */
+    this.segmentReplacement_ = segmentReplacement;
+
+    /** @const {number} */
+    this.timeReplacement_ = timeReplacement;
+
+    /** @const {!Array.<!goog.Uri>} */
+    this.urls = [];
+
+    /** @const {number} */
+    this.startByte = 0;
+
+    /** @const {?number} */
+    this.endByte = null;
+
+    /** @private {?Promise} */
+    this.requestPromise_ = null;
+
+    /** @private {shaka.util.AjaxRequest} */
+    this.request_ = null;
+
+    /** @private {shaka.util.FailoverUri.NetworkCallback} */
+    this.callback2_ = callback;
+
+    /** @type {goog.Uri} */
+    this.currentUrl = null;
+};
+
+goog.inherits(shaka.vimond.DeferredUri, shaka.util.FailoverUri);
+
+/**
+ * Constructs and returns the Uri when needed.
+ * @private
+ * @returns {shaka.util.FailoverUri}
+ */
+shaka.vimond.DeferredUri.prototype.getUri_ = function() {
+    "use strict";
+    return shaka.dash.MpdUtils.createFromTemplate(
+        this.callback2_, this.representation_, this.segmentReplacement_,
+        this.timeReplacement_, 0, null);
+};
+
+/** @override */
+shaka.vimond.DeferredUri.prototype.fetch = function(opt_parameters, opt_estimator) {
+    "use strict";
+    this.urls.push(this.getUri_().urls[0]);
+    return shaka.util.FailoverUri.prototype.fetch.call(this, opt_parameters, opt_estimator);
+};
+
+/** @override */
+shaka.vimond.DeferredUri.prototype.isOfflineUri = function() {
+    return false;
+};