1 files changed, 244 insertions, 0 deletions
diff --git a/dom/media/flac/FlacFrameParser.cpp b/dom/media/flac/FlacFrameParser.cpp
new file mode 100644
index 0000000000..c042a7d334
--- /dev/null
+++ b/dom/media/flac/FlacFrameParser.cpp
@@ -0,0 +1,244 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "FlacFrameParser.h"
+#include "nsTArray.h"
+#include "OggCodecState.h"
+#include "OpusParser.h"
+#include "VideoUtils.h"
+#include "BufferReader.h"
+#include "mozilla/ResultExtensions.h"
+
+namespace mozilla {
+
+#define OGG_FLAC_METADATA_TYPE_STREAMINFO 0x7F
+#define FLAC_STREAMINFO_SIZE 34
+
+#define BITMASK(x) ((1ULL << x) - 1)
+
+enum {
+  FLAC_METADATA_TYPE_STREAMINFO = 0,
+  FLAC_METADATA_TYPE_PADDING,
+  FLAC_METADATA_TYPE_APPLICATION,
+  FLAC_METADATA_TYPE_SEEKTABLE,
+  FLAC_METADATA_TYPE_VORBIS_COMMENT,
+  FLAC_METADATA_TYPE_CUESHEET,
+  FLAC_METADATA_TYPE_PICTURE,
+  FLAC_METADATA_TYPE_INVALID = 127
+};
+
+FlacFrameParser::FlacFrameParser()
+    : mMinBlockSize(0),
+      mMaxBlockSize(0),
+      mMinFrameSize(0),
+      mMaxFrameSize(0),
+      mNumFrames(0),
+      mFullMetadata(false),
+      mPacketCount(0){};
+
+FlacFrameParser::~FlacFrameParser() = default;
+
+uint32_t FlacFrameParser::HeaderBlockLength(const uint8_t* aPacket) const {
+  uint32_t extra = 4;
+  if (aPacket[0] == 'f') {
+    // This must be the first block read, which contains the fLaC signature.
+    aPacket += 4;
+    extra += 4;
+  }
+  return (BigEndian::readUint32(aPacket) & BITMASK(24)) + extra;
+}
+
+Result<Ok, nsresult> FlacFrameParser::DecodeHeaderBlock(const uint8_t* aPacket,
+                                                        size_t aLength) {
+  if (aLength < 4 || aPacket[0] == 0xff) {
+    // Not a header block.
+    return Err(NS_ERROR_FAILURE);
+  }
+  BufferReader br(aPacket, aLength);
+
+  mPacketCount++;
+
+  if (aPacket[0] == 'f') {
+    if (mPacketCount != 1 || memcmp(br.Read(4), "fLaC", 4) ||
+        br.Remaining() != FLAC_STREAMINFO_SIZE + 4) {
+      return Err(NS_ERROR_FAILURE);
+    }
+  }
+  uint8_t blockHeader;
+  MOZ_TRY_VAR(blockHeader, br.ReadU8());
+  // blockType is a misnomer as it could indicate here either a packet type
+  // should it points to the start of a Flac in Ogg metadata, or an actual
+  // block type as per the flac specification.
+  uint32_t blockType = blockHeader & 0x7f;
+  bool lastBlock = blockHeader & 0x80;
+
+  if (blockType == OGG_FLAC_METADATA_TYPE_STREAMINFO) {
+    if (mPacketCount != 1 || memcmp(br.Read(4), "FLAC", 4) ||
+        br.Remaining() != FLAC_STREAMINFO_SIZE + 12) {
+      return Err(NS_ERROR_FAILURE);
+    }
+    uint32_t major;
+    MOZ_TRY_VAR(major, br.ReadU8());
+    if (major != 1) {
+      // unsupported version;
+      return Err(NS_ERROR_FAILURE);
+    }
+    MOZ_TRY(br.ReadU8());  // minor version
+    uint32_t header;
+    MOZ_TRY_VAR(header, br.ReadU16());
+    mNumHeaders = Some(header);
+    br.Read(4);  // fLaC
+    MOZ_TRY_VAR(blockType, br.ReadU8());
+    blockType &= BITMASK(7);
+    // First METADATA_BLOCK_STREAMINFO
+    if (blockType != FLAC_METADATA_TYPE_STREAMINFO) {
+      // First block must be a stream info.
+      return Err(NS_ERROR_FAILURE);
+    }
+  }
+
+  uint32_t blockDataSize;
+  MOZ_TRY_VAR(blockDataSize, br.ReadU24());
+  const uint8_t* blockDataStart = br.Peek(blockDataSize);
+  if (!blockDataStart) {
+    // Incomplete block.
+    return Err(NS_ERROR_FAILURE);
+  }
+
+  switch (blockType) {
+    case FLAC_METADATA_TYPE_STREAMINFO: {
+      if (mPacketCount != 1 || blockDataSize != FLAC_STREAMINFO_SIZE) {
+        // STREAMINFO must be the first metadata block found, and its size
+        // is constant.
+        return Err(NS_ERROR_FAILURE);
+      }
+
+      MOZ_TRY_VAR(mMinBlockSize, br.ReadU16());
+      MOZ_TRY_VAR(mMaxBlockSize, br.ReadU16());
+      MOZ_TRY_VAR(mMinFrameSize, br.ReadU24());
+      MOZ_TRY_VAR(mMaxFrameSize, br.ReadU24());
+
+      uint64_t blob;
+      MOZ_TRY_VAR(blob, br.ReadU64());
+      uint32_t sampleRate = (blob >> 44) & BITMASK(20);
+      if (!sampleRate) {
+        return Err(NS_ERROR_FAILURE);
+      }
+      uint32_t numChannels = ((blob >> 41) & BITMASK(3)) + 1;
+      if (numChannels > FLAC_MAX_CHANNELS) {
+        return Err(NS_ERROR_FAILURE);
+      }
+      uint32_t bps = ((blob >> 36) & BITMASK(5)) + 1;
+      if (bps > 24) {
+        return Err(NS_ERROR_FAILURE);
+      }
+      mNumFrames = blob & BITMASK(36);
+
+      mInfo.mMimeType = "audio/flac";
+      mInfo.mRate = sampleRate;
+      mInfo.mChannels = numChannels;
+      mInfo.mBitDepth = bps;
+      FlacCodecSpecificData flacCodecSpecificData;
+      flacCodecSpecificData.mStreamInfoBinaryBlob->AppendElements(
+          blockDataStart, blockDataSize);
+      mInfo.mCodecSpecificConfig =
+          AudioCodecSpecificVariant{std::move(flacCodecSpecificData)};
+      auto duration = media::TimeUnit(mNumFrames, sampleRate);
+      mInfo.mDuration = duration.IsValid() ? duration : media::TimeUnit::Zero();
+      mParser = MakeUnique<OpusParser>();
+      break;
+    }
+    case FLAC_METADATA_TYPE_VORBIS_COMMENT: {
+      if (!mParser) {
+        // We must have seen a valid streaminfo first.
+        return Err(NS_ERROR_FAILURE);
+      }
+      nsTArray<uint8_t> comments(blockDataSize + 8);
+      comments.AppendElements("OpusTags", 8);
+      comments.AppendElements(blockDataStart, blockDataSize);
+      if (!mParser->DecodeTags(comments.Elements(), comments.Length())) {
+        return Err(NS_ERROR_FAILURE);
+      }
+      break;
+    }
+    default:
+      break;
+  }
+
+  if (mNumHeaders && mPacketCount > mNumHeaders.ref() + 1) {
+    // Received too many header block. assuming invalid.
+    return Err(NS_ERROR_FAILURE);
+  }
+
+  if (lastBlock || (mNumHeaders && mNumHeaders.ref() + 1 == mPacketCount)) {
+    mFullMetadata = true;
+  }
+
+  return Ok();
+}
+
+int64_t FlacFrameParser::BlockDuration(const uint8_t* aPacket,
+                                       size_t aLength) const {
+  if (!mInfo.IsValid()) {
+    return -1;
+  }
+  if (mMinBlockSize == mMaxBlockSize) {
+    // block size is fixed, use this instead of looking at the frame header.
+    return mMinBlockSize;
+  }
+  // TODO
+  return 0;
+}
+
+Result<bool, nsresult> FlacFrameParser::IsHeaderBlock(const uint8_t* aPacket,
+                                                      size_t aLength) const {
+  // Ogg Flac header
+  // The one-byte packet type 0x7F
+  // The four-byte ASCII signature "FLAC", i.e. 0x46, 0x4C, 0x41, 0x43
+
+  // Flac header:
+  // "fLaC", the FLAC stream marker in ASCII, meaning byte 0 of the stream is
+  // 0x66, followed by 0x4C 0x61 0x43
+
+  // If we detect either a ogg or plain flac header, then it must be valid.
+  if (aLength < 4 || aPacket[0] == 0xff) {
+    // A header is at least 4 bytes.
+    return false;
+  }
+  if (aPacket[0] == 0x7f) {
+    // Ogg packet
+    BufferReader br(aPacket + 1, aLength - 1);
+    const uint8_t* signature = br.Read(4);
+    return signature && !memcmp(signature, "FLAC", 4);
+  }
+  BufferReader br(aPacket, aLength - 1);
+  const uint8_t* signature = br.Read(4);
+  if (signature && !memcmp(signature, "fLaC", 4)) {
+    // Flac start header, must have STREAMINFO as first metadata block;
+    uint32_t blockType;
+    MOZ_TRY_VAR(blockType, br.ReadU8());
+    blockType &= 0x7f;
+    return blockType == FLAC_METADATA_TYPE_STREAMINFO;
+  }
+  char type = aPacket[0] & 0x7f;
+  return type >= 1 && type <= 6;
+}
+
+UniquePtr<MetadataTags> FlacFrameParser::GetTags() const {
+  if (!mParser) {
+    return nullptr;
+  }
+
+  auto tags = MakeUnique<MetadataTags>();
+  for (uint32_t i = 0; i < mParser->mTags.Length(); i++) {
+    OggCodecState::AddVorbisComment(tags, mParser->mTags[i].Data(),
+                                    mParser->mTags[i].Length());
+  }
+
+  return tags;
+}
+
+}  // namespace mozilla