Allow H264 bitstream parser to fail gracefully

webrtc/common_video/h264/h264_bitstream_parser.h

 /*
  *  Copyright (c) 2015 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 13 matching lines @@
 namespace webrtc {
 
 // Stateful H264 bitstream parser (due to SPS/PPS). Used to parse out QP values
 // from the bitstream.
 // TODO(pbos): Unify with RTP SPS parsing and only use one H264 parser.
 // TODO(pbos): If/when this gets used on the receiver side CHECKs must be
 // removed and gracefully abort as we have no control over receive-side
 // bitstreams.
 class H264BitstreamParser {
  public:
+  enum Result {
+    kOk,
+    kInvalidStream,
+    kUnsupportedStream,
+  };
+
   H264BitstreamParser();
   virtual ~H264BitstreamParser();
 
   // Parse an additional chunk of H264 bitstream.
   void ParseBitstream(const uint8_t* bitstream, size_t length);
 
   // Get the last extracted QP value from the parsed bitstream.
   bool GetLastSliceQp(int* qp) const;
 
  protected:
   void ParseSlice(const uint8_t* slice, size_t length);
-  bool ParseNonParameterSetNalu(const uint8_t* source,
-                                size_t source_length,
-                                uint8_t nalu_type);
+  Result ParseNonParameterSetNalu(const uint8_t* source,
+                                  size_t source_length,
+                                  uint8_t nalu_type);
 
   // SPS/PPS state, updated when parsing new SPS/PPS, used to parse slices.
   rtc::Optional<SpsParser::SpsState> sps_;
   rtc::Optional<PpsParser::PpsState> pps_;
 
   // Last parsed slice QP.
   rtc::Optional<int32_t> last_slice_qp_delta_;
 };
 
 }  // namespace webrtc
 
 #endif  // WEBRTC_COMMON_VIDEO_H264_H264_BITSTREAM_PARSER_H_