From a394641f2e7ca1041e1677ac028f417e8390aadf Mon Sep 17 00:00:00 2001
From: Alvaro Velad Galvan <ladvan91@hotmail.com>
Date: Thu, 27 Apr 2023 16:32:22 +0200
Subject: [PATCH] fix: Fix buffering on the end of MSS streams

---
 lib/mss/mss_parser.js              | 25 +++++++++++--------
 test/mss/mss_player_integration.js | 40 ++++++++++++++++++++++++++++++
 2 files changed, 54 insertions(+), 11 deletions(-)

diff --git a/lib/mss/mss_parser.js b/lib/mss/mss_parser.js
index e8e4ab3e369..10dcded2695 100644
--- a/lib/mss/mss_parser.js
+++ b/lib/mss/mss_parser.js
@@ -54,6 +54,9 @@ shaka.mss.MssParser = class {
      */
     this.updatePeriod_ = 0;
 
+    /** @private {?shaka.media.PresentationTimeline} */
+    this.presentationTimeline_ = null;
+
     /**
      * An ewma that tracks how long updates take.
      * This is to mitigate issues caused by slow parsing on embedded devices.
@@ -286,12 +289,8 @@ shaka.mss.MssParser = class {
       manifestPreprocessor(mss);
     }
 
-    /** @type {!shaka.media.PresentationTimeline} */
-    let presentationTimeline;
-    if (this.manifest_) {
-      presentationTimeline = this.manifest_.presentationTimeline;
-    } else {
-      presentationTimeline = new shaka.media.PresentationTimeline(
+    if (!this.presentationTimeline_) {
+      this.presentationTimeline_ = new shaka.media.PresentationTimeline(
           /* presentationStartTime= */ null, /* delay= */ 0);
     }
 
@@ -305,7 +304,7 @@ shaka.mss.MssParser = class {
           shaka.util.Error.Code.MSS_LIVE_CONTENT_NOT_SUPPORTED);
     }
 
-    presentationTimeline.setStatic(!isLive);
+    this.presentationTimeline_.setStatic(!isLive);
 
     const timescale = XmlUtils.parseAttr(mss, 'TimeScale',
         XmlUtils.parseNonNegativeInt, shaka.mss.MssParser.DEFAULT_TIME_SCALE_);
@@ -342,7 +341,7 @@ shaka.mss.MssParser = class {
       segmentAvailabilityDuration = Infinity;
     }
 
-    presentationTimeline.setSegmentAvailabilityDuration(
+    this.presentationTimeline_.setSegmentAvailabilityDuration(
         segmentAvailabilityDuration);
 
     // Duration in timescale units.
@@ -352,7 +351,7 @@ shaka.mss.MssParser = class {
         'Duration must be defined!');
 
     if (!isLive) {
-      presentationTimeline.setDuration(duration / timescale);
+      this.presentationTimeline_.setDuration(duration / timescale);
     }
 
     /** @type {!shaka.mss.MssParser.Context} */
@@ -368,7 +367,7 @@ shaka.mss.MssParser = class {
     // These steps are not done on manifest update.
     if (!this.manifest_) {
       this.manifest_ = {
-        presentationTimeline: presentationTimeline,
+        presentationTimeline: this.presentationTimeline_,
         variants: context.variants,
         textStreams: context.textStreams,
         imageStreams: [],
@@ -382,7 +381,7 @@ shaka.mss.MssParser = class {
       // This is the first point where we have a meaningful presentation start
       // time, and we need to tell PresentationTimeline that so that it can
       // maintain consistency from here on.
-      presentationTimeline.lockStartTime();
+      this.presentationTimeline_.lockStartTime();
     } else {
       // Just update the variants and text streams.
       this.manifest_.variants = context.variants;
@@ -491,6 +490,10 @@ shaka.mss.MssParser = class {
       duration = end - start;
     }
 
+    const presentationDuration = this.presentationTimeline_.getDuration();
+    this.presentationTimeline_.setDuration(
+        Math.min(duration, presentationDuration));
+
     /** @type {!shaka.extern.Stream} */
     const stream = {
       id: id,
diff --git a/test/mss/mss_player_integration.js b/test/mss/mss_player_integration.js
index e136df95eff..63f417717dc 100644
--- a/test/mss/mss_player_integration.js
+++ b/test/mss/mss_player_integration.js
@@ -79,6 +79,46 @@ describe('MSS Player', () => {
     // longer than 10 seconds, fail the test.
     await waiter.waitUntilPlayheadReachesOrFailOnTimeout(video, 5, 10);
 
+    if (video.ended) {
+      checkEndedTime();
+    } else {
+      // Expect that in 30 seconds of playback, we go through at least 20
+      // seconds of content.  This allows for some buffering or network
+      // flake.
+      expect(video.currentTime).toBeGreaterThan(5);
+
+      // Since video.ended is false, we expect the current time to be before
+      // the video duration.
+      expect(video.currentTime).toBeLessThan(video.duration);
+
+      // Seek close to the end and play the rest of the content.
+      video.currentTime = video.duration - 5;
+
+      // Wait for the video to start playback again after seeking.  If it
+      // takes longer than 10 seconds, fail the test.
+      await waiter.waitForMovementOrFailOnTimeout(video, 10);
+
+      // Play for 20 seconds, but stop early if the video ends.
+      await waiter.waitForEndOrTimeout(video, 20);
+
+      checkEndedTime();
+    }
+
     await player.unload();
   });
+
+  /**
+   * Check the video time for videos that we expect to have ended.
+   */
+  function checkEndedTime() {
+    if (video.currentTime >= video.duration) {
+      // On some platforms, currentTime surpasses duration by more than 1s.
+      // For the purposes of this test, this is fine, so don't set any precise
+      // expectations on currentTime if it's larger.
+    } else {
+      // On some platforms, currentTime is less than duration, but it should be
+      // close.
+      expect(video.currentTime).toBeGreaterThan(video.duration - 1);
+    }
+  }
 });