fix(Prefetch): Ensure prefetched segments are continuous (shaka-proje…

…ct#6908) Follow up to shaka-project#6899
Leena-Sharma-rsys · Jun 25, 2024 · db679e0 · db679e0
1 parent b5f1ee9
commit db679e0
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Showing 2 changed files with 26 additions and 8 deletions.
diff --git a/lib/media/segment_prefetch.js b/lib/media/segment_prefetch.js
@@ -93,15 +93,14 @@ shaka.media.SegmentPrefetch = class {
       shaka.log.debug(logPrefix, 'missing iterator');
       return;
     }
-    let reference = this.iterator_.next().value;
     if (skipFirst) {
-      reference = this.iterator_.next().value;
+      this.iterator_.next();
     }
-    if (!reference) {
-      return;
-    }
-    while (this.segmentPrefetchMap_.size < this.prefetchLimit_ &&
-            reference != null) {
+    while (this.segmentPrefetchMap_.size < this.prefetchLimit_) {
+      const reference = this.iterator_.next().value;
+      if (!reference) {
+        break;
+      }
       // By default doesn't prefech preload partial segments when using
       // byterange
       let prefetchAllowed = true;
@@ -125,7 +124,6 @@ shaka.media.SegmentPrefetch = class {
           reference.isLastPartial()) {
         break;
       }
-      reference = this.iterator_.next().value;
     }
     this.clearInitSegments_();
   }

diff --git a/test/media/segment_prefetch_unit.js b/test/media/segment_prefetch_unit.js
@@ -132,6 +132,26 @@ describe('SegmentPrefetch', () => {
       expect(op).toBeNull();
       await expectSegmentsPrefetched(1);
     });
+
+    it('properly iterates on subsequent prefetchSegments calls', async () => {
+      segmentPrefetch.resetLimit(1);
+      segmentPrefetch.prefetchSegmentsByTime(references[0].startTime);
+      let op = segmentPrefetch.getPrefetchedSegment(references[1]);
+      expect(op).toBeNull();
+      await expectSegmentsPrefetched(0, 1);
+
+      // Evict our only one prefetched segment.
+      segmentPrefetch.evict(references[1].endTime);
+      op = segmentPrefetch.getPrefetchedSegment(references[0]);
+      expect(op).toBeNull();
+
+      // Underlying iterator should traverse to next element, regardless
+      // of specified time.
+      segmentPrefetch.prefetchSegmentsByTime(references[0].startTime);
+      op = segmentPrefetch.getPrefetchedSegment(references[0]);
+      expect(op).toBeNull();
+      await expectSegmentsPrefetched(1, 1);
+    });
   });
 
   describe('clearAll', () => {