From 0d6ec21b30e13d7aba8c1273019b54c63cad10c1 Mon Sep 17 00:00:00 2001
From: bachinger <bachinger@google.com>
Date: Thu, 29 Oct 2020 20:44:49 +0000
Subject: [PATCH] Parse #EXT-X-PRELOAD-HINT tag

Issue: #5011
PiperOrigin-RevId: 339738292
---
 .../hls/playlist/HlsPlaylistParser.java       |  53 +++++++
 .../playlist/HlsMediaPlaylistParserTest.java  | 149 ++++++++++++++++++
 2 files changed, 202 insertions(+)

diff --git a/library/hls/src/main/java/com/google/android/exoplayer2/source/hls/playlist/HlsPlaylistParser.java b/library/hls/src/main/java/com/google/android/exoplayer2/source/hls/playlist/HlsPlaylistParser.java
index 1f9ad1b703..03408776b3 100644
--- a/library/hls/src/main/java/com/google/android/exoplayer2/source/hls/playlist/HlsPlaylistParser.java
+++ b/library/hls/src/main/java/com/google/android/exoplayer2/source/hls/playlist/HlsPlaylistParser.java
@@ -93,11 +93,14 @@ public final class HlsPlaylistParser implements ParsingLoadable.Parser<HlsPlayli
   private static final String TAG_BYTERANGE = "#EXT-X-BYTERANGE";
   private static final String TAG_GAP = "#EXT-X-GAP";
   private static final String TAG_SKIP = "#EXT-X-SKIP";
+  private static final String TAG_PRELOAD_HINT = "#EXT-X-PRELOAD-HINT";
 
   private static final String TYPE_AUDIO = "AUDIO";
   private static final String TYPE_VIDEO = "VIDEO";
   private static final String TYPE_SUBTITLES = "SUBTITLES";
   private static final String TYPE_CLOSED_CAPTIONS = "CLOSED-CAPTIONS";
+  private static final String TYPE_PART = "PART";
+  private static final String TYPE_MAP = "MAP";
 
   private static final String METHOD_NONE = "NONE";
   private static final String METHOD_AES_128 = "AES-128";
@@ -157,6 +160,9 @@ public final class HlsPlaylistParser implements ParsingLoadable.Parser<HlsPlayli
       + ":(\\d+(?:@\\d+)?)\\b");
   private static final Pattern REGEX_ATTR_BYTERANGE =
       Pattern.compile("BYTERANGE=\"(\\d+(?:@\\d+)?)\\b\"");
+  private static final Pattern REGEX_BYTERANGE_START = Pattern.compile("BYTERANGE-START=(\\d+)\\b");
+  private static final Pattern REGEX_BYTERANGE_LENGTH =
+      Pattern.compile("BYTERANGE-LENGTH=(\\d+)\\b");
   private static final Pattern REGEX_METHOD =
       Pattern.compile(
           "METHOD=("
@@ -178,6 +184,8 @@ public final class HlsPlaylistParser implements ParsingLoadable.Parser<HlsPlayli
   private static final Pattern REGEX_IV = Pattern.compile("IV=([^,.*]+)");
   private static final Pattern REGEX_TYPE = Pattern.compile("TYPE=(" + TYPE_AUDIO + "|" + TYPE_VIDEO
       + "|" + TYPE_SUBTITLES + "|" + TYPE_CLOSED_CAPTIONS + ")");
+  private static final Pattern REGEX_PRELOAD_HINT_TYPE =
+      Pattern.compile("TYPE=(" + TYPE_PART + "|" + TYPE_MAP + ")");
   private static final Pattern REGEX_LANGUAGE = Pattern.compile("LANGUAGE=\"(.+?)\"");
   private static final Pattern REGEX_NAME = Pattern.compile("NAME=\"(.+?)\"");
   private static final Pattern REGEX_GROUP_ID = Pattern.compile("GROUP-ID=\"(.+?)\"");
@@ -592,6 +600,7 @@ public final class HlsPlaylistParser implements ParsingLoadable.Parser<HlsPlayli
     long partTargetDurationUs = C.TIME_UNSET;
     boolean hasIndependentSegmentsTag = masterPlaylist.hasIndependentSegments;
     boolean hasEndTag = false;
+    boolean seenPreloadPart = false;
     @Nullable Segment initializationSegment = null;
     HashMap<String, String> variableDefinitions = new HashMap<>();
     HashMap<String, Segment> urlToInferredInitSegment = new HashMap<>();
@@ -760,6 +769,42 @@ public final class HlsPlaylistParser implements ParsingLoadable.Parser<HlsPlayli
         hasIndependentSegmentsTag = true;
       } else if (line.equals(TAG_ENDLIST)) {
         hasEndTag = true;
+      } else if (line.startsWith(TAG_PRELOAD_HINT) && !seenPreloadPart) {
+        String type = parseStringAttr(line, REGEX_PRELOAD_HINT_TYPE, variableDefinitions);
+        if (!TYPE_PART.equals(type)) {
+          continue;
+        }
+        String url = parseStringAttr(line, REGEX_URI, variableDefinitions);
+        long byteRangeStart =
+            parseOptionalLongAttr(line, REGEX_BYTERANGE_START, /* defaultValue= */ 0);
+        long byteRangeLength =
+            parseOptionalLongAttr(line, REGEX_BYTERANGE_LENGTH, /* defaultValue= */ C.TIME_UNSET);
+        @Nullable
+        String segmentEncryptionIV =
+            getSegmentEncryptionIV(
+                segmentMediaSequence, fullSegmentEncryptionKeyUri, fullSegmentEncryptionIV);
+        if (cachedDrmInitData == null && !currentSchemeDatas.isEmpty()) {
+          SchemeData[] schemeDatas = currentSchemeDatas.values().toArray(new SchemeData[0]);
+          cachedDrmInitData = new DrmInitData(encryptionScheme, schemeDatas);
+          if (playlistProtectionSchemes == null) {
+            playlistProtectionSchemes = getPlaylistProtectionSchemes(encryptionScheme, schemeDatas);
+          }
+        }
+        parts.add(
+            new Part(
+                url,
+                initializationSegment,
+                /* durationUs= */ 0,
+                relativeDiscontinuitySequence,
+                partStartTimeUs,
+                cachedDrmInitData,
+                fullSegmentEncryptionKeyUri,
+                segmentEncryptionIV,
+                byteRangeStart,
+                byteRangeLength,
+                /* hasGapTag= */ false,
+                /* isIndependent= */ false));
+        seenPreloadPart = true;
       } else if (line.startsWith(TAG_PART)) {
         @Nullable
         String segmentEncryptionIV =
@@ -1027,6 +1072,14 @@ public final class HlsPlaylistParser implements ParsingLoadable.Parser<HlsPlayli
     return Long.parseLong(parseStringAttr(line, pattern, Collections.emptyMap()));
   }
 
+  private static long parseOptionalLongAttr(String line, Pattern pattern, long defaultValue) {
+    Matcher matcher = pattern.matcher(line);
+    if (matcher.find()) {
+      return Long.parseLong(checkNotNull(matcher.group(1)));
+    }
+    return defaultValue;
+  }
+
   private static double parseDoubleAttr(String line, Pattern pattern) throws ParserException {
     return Double.parseDouble(parseStringAttr(line, pattern, Collections.emptyMap()));
   }
diff --git a/library/hls/src/test/java/com/google/android/exoplayer2/source/hls/playlist/HlsMediaPlaylistParserTest.java b/library/hls/src/test/java/com/google/android/exoplayer2/source/hls/playlist/HlsMediaPlaylistParserTest.java
index 88a2a2f2fb..b917cd2c11 100644
--- a/library/hls/src/test/java/com/google/android/exoplayer2/source/hls/playlist/HlsMediaPlaylistParserTest.java
+++ b/library/hls/src/test/java/com/google/android/exoplayer2/source/hls/playlist/HlsMediaPlaylistParserTest.java
@@ -487,6 +487,155 @@ public class HlsMediaPlaylistParserTest {
     assertThat(part.encryptionIV).isEqualTo("0x410C8AC18AA42EFA18B5155484F5FC34");
   }
 
+  @Test
+  public void parseMediaPlaylist_withPreloadHintTypePart_hasPreloadPartWithAllAttributes()
+      throws IOException {
+    Uri playlistUri = Uri.parse("https://example.com/test.m3u8");
+    String playlistString =
+        "#EXTM3U\n"
+            + "#EXT-X-TARGETDURATION:4\n"
+            + "#EXT-X-VERSION:6\n"
+            + "#EXT-X-MEDIA-SEQUENCE:266\n"
+            + "#EXT-X-MAP:URI=\"map.mp4\"\n"
+            + "#EXT-X-KEY:METHOD=AES-128,KEYFORMAT=\"identity\""
+            + ", IV=0x410C8AC18AA42EFA18B5155484F5FC34,URI=\"fake://foo.bar/uri\"\n"
+            + "#EXTINF:4.00000,\n"
+            + "fileSequence266.mp4\n"
+            + "#EXT-X-PART:DURATION=2.00000,URI=\"part267.1.ts\"\n"
+            + "#EXT-X-PRELOAD-HINT:TYPE=PART,BYTERANGE-START=1234,BYTERANGE-LENGTH=1000,"
+            + "URI=\"filePart267.2.ts\"\n";
+    InputStream inputStream = new ByteArrayInputStream(Util.getUtf8Bytes(playlistString));
+
+    HlsMediaPlaylist playlist =
+        (HlsMediaPlaylist) new HlsPlaylistParser().parse(playlistUri, inputStream);
+
+    assertThat(playlist.segments.get(0).parts).isEmpty();
+    assertThat(playlist.trailingParts).hasSize(2);
+    HlsMediaPlaylist.Part preloadPart = playlist.trailingParts.get(1);
+    assertThat(preloadPart.durationUs).isEqualTo(0L);
+    assertThat(preloadPart.url).isEqualTo("filePart267.2.ts");
+    assertThat(preloadPart.byteRangeLength).isEqualTo(1000);
+    assertThat(preloadPart.byteRangeOffset).isEqualTo(1234);
+    assertThat(preloadPart.initializationSegment.url).isEqualTo("map.mp4");
+    assertThat(preloadPart.encryptionIV).isEqualTo("0x410C8AC18AA42EFA18B5155484F5FC34");
+  }
+
+  @Test
+  public void parseMediaPlaylist_withMultiplePreloadHintTypeParts_picksOnlyFirstPreloadPart()
+      throws IOException {
+    Uri playlistUri = Uri.parse("https://example.com/test.m3u8");
+    String playlistString =
+        "#EXTM3U\n"
+            + "#EXT-X-TARGETDURATION:4\n"
+            + "#EXT-X-VERSION:6\n"
+            + "#EXT-X-MEDIA-SEQUENCE:266\n"
+            + "#EXT-X-PART:DURATION=2.00000,URI=\"part267.1.ts\"\n"
+            + "#EXT-X-PRELOAD-HINT:TYPE=PART,URI=\"filePart267.2.ts\"\n"
+            + "#EXT-X-PRELOAD-HINT:TYPE=PART,URI=\"filePart267.3.ts\"\n";
+    InputStream inputStream = new ByteArrayInputStream(Util.getUtf8Bytes(playlistString));
+
+    HlsMediaPlaylist playlist =
+        (HlsMediaPlaylist) new HlsPlaylistParser().parse(playlistUri, inputStream);
+
+    assertThat(playlist.trailingParts).hasSize(2);
+    assertThat(playlist.trailingParts.get(1).url).isEqualTo("filePart267.2.ts");
+  }
+
+  @Test
+  public void parseMediaPlaylist_withPreloadHintTypePartAndAesPlayReadyKey_inheritsDrmInitData()
+      throws IOException {
+    Uri playlistUri = Uri.parse("https://example.com/test.m3u8");
+    String playlistString =
+        "#EXTM3U\n"
+            + "#EXT-X-TARGETDURATION:4\n"
+            + "#EXT-X-VERSION:6\n"
+            + "#EXT-X-MEDIA-SEQUENCE:266\n"
+            + "#EXT-X-KEY:METHOD=SAMPLE-AES,"
+            + "KEYFORMAT=\"com.microsoft.playready\","
+            + "URI=\"data:text/plain;base64,RG9uJ3QgeW91IGdldCB0aXJlZCBvZiBkb2luZyB0aGlzPw==\"\n"
+            + "#EXTINF:4.00000,\n"
+            + "fileSequence266.mp4\n"
+            + "#EXT-X-PRELOAD-HINT:TYPE=PART,URI=\"filePart267.2.ts\"\n";
+    InputStream inputStream = new ByteArrayInputStream(Util.getUtf8Bytes(playlistString));
+
+    HlsMediaPlaylist playlist =
+        (HlsMediaPlaylist) new HlsPlaylistParser().parse(playlistUri, inputStream);
+
+    assertThat(playlist.segments.get(0).parts).isEmpty();
+    assertThat(playlist.trailingParts).hasSize(1);
+    assertThat(playlist.protectionSchemes.schemeDataCount).isEqualTo(1);
+    HlsMediaPlaylist.Part preloadPart = playlist.trailingParts.get(0);
+    assertThat(preloadPart.drmInitData.schemeType).isEqualTo("cbcs");
+    assertThat(preloadPart.drmInitData.schemeDataCount).isEqualTo(1);
+    assertThat(preloadPart.drmInitData.get(0).uuid).isEqualTo(C.PLAYREADY_UUID);
+    assertThat(preloadPart.drmInitData.get(0).data)
+        .isEqualTo(
+            PsshAtomUtil.buildPsshAtom(
+                C.PLAYREADY_UUID,
+                Base64.decode("RG9uJ3QgeW91IGdldCB0aXJlZCBvZiBkb2luZyB0aGlzPw==", Base64.DEFAULT)));
+  }
+
+  @Test
+  public void parseMediaPlaylist_withPreloadHintTypePartAndNewAesPlayReadyKey_correctDrmInitData()
+      throws IOException {
+    Uri playlistUri = Uri.parse("https://example.com/test.m3u8");
+    String playlistString =
+        "#EXTM3U\n"
+            + "#EXT-X-TARGETDURATION:4\n"
+            + "#EXT-X-VERSION:6\n"
+            + "#EXT-X-MEDIA-SEQUENCE:266\n"
+            + "#EXTINF:4.00000,\n"
+            + "fileSequence266.mp4\n"
+            + "#EXT-X-KEY:METHOD=SAMPLE-AES,"
+            + "KEYFORMAT=\"com.microsoft.playready\","
+            + "URI=\"data:text/plain;base64,RG9uJ3QgeW91IGdldCB0aXJlZCBvZiBkb2luZyB0aGlzPw==\"\n"
+            + "#EXT-X-PRELOAD-HINT:TYPE=PART,URI=\"filePart267.2.ts\"\n";
+    InputStream inputStream = new ByteArrayInputStream(Util.getUtf8Bytes(playlistString));
+
+    HlsMediaPlaylist playlist =
+        (HlsMediaPlaylist) new HlsPlaylistParser().parse(playlistUri, inputStream);
+
+    assertThat(playlist.segments.get(0).parts).isEmpty();
+    assertThat(playlist.trailingParts).hasSize(1);
+    assertThat(playlist.protectionSchemes.schemeDataCount).isEqualTo(1);
+    HlsMediaPlaylist.Part preloadPart = playlist.trailingParts.get(0);
+    assertThat(preloadPart.drmInitData.schemeType).isEqualTo("cbcs");
+    assertThat(preloadPart.drmInitData.schemeDataCount).isEqualTo(1);
+    assertThat(preloadPart.drmInitData.get(0).uuid).isEqualTo(C.PLAYREADY_UUID);
+    assertThat(preloadPart.drmInitData.get(0).data)
+        .isEqualTo(
+            PsshAtomUtil.buildPsshAtom(
+                C.PLAYREADY_UUID,
+                Base64.decode("RG9uJ3QgeW91IGdldCB0aXJlZCBvZiBkb2luZyB0aGlzPw==", Base64.DEFAULT)));
+  }
+
+  @Test
+  public void parseMediaPlaylist_withPreloadHintTypePartAndAes128_partHasDrmKeyUriAndIV()
+      throws IOException {
+    Uri playlistUri = Uri.parse("https://example.com/test.m3u8");
+    String playlistString =
+        "#EXTM3U\n"
+            + "#EXT-X-TARGETDURATION:4\n"
+            + "#EXT-X-VERSION:6\n"
+            + "#EXT-X-MEDIA-SEQUENCE:266\n"
+            + "#EXTINF:4.00000,\n"
+            + "fileSequence266.mp4\n"
+            + "#EXT-X-KEY:METHOD=AES-128,KEYFORMAT=\"identity\""
+            + ", IV=0x410C8AC18AA42EFA18B5155484F5FC34,URI=\"fake://foo.bar/uri\"\n"
+            + "#EXT-X-PRELOAD-HINT:TYPE=PART,URI=\"filePart267.2.ts\"\n";
+    InputStream inputStream = new ByteArrayInputStream(Util.getUtf8Bytes(playlistString));
+
+    HlsMediaPlaylist playlist =
+        (HlsMediaPlaylist) new HlsPlaylistParser().parse(playlistUri, inputStream);
+
+    assertThat(playlist.segments.get(0).parts).isEmpty();
+    assertThat(playlist.trailingParts).hasSize(1);
+    HlsMediaPlaylist.Part preloadPart = playlist.trailingParts.get(0);
+    assertThat(preloadPart.drmInitData).isNull();
+    assertThat(preloadPart.fullSegmentEncryptionKeyUri).isEqualTo("fake://foo.bar/uri");
+    assertThat(preloadPart.encryptionIV).isEqualTo("0x410C8AC18AA42EFA18B5155484F5FC34");
+  }
+
   @Test
   public void multipleExtXKeysForSingleSegment() throws Exception {
     Uri playlistUri = Uri.parse("https://example.com/test.m3u8");