experiment with -Wimplicit-fallthrough

net/quic/crypto/crypto_framer.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "net/quic/crypto/crypto_framer.h"
 
 #include "net/quic/crypto/crypto_handshake.h"
 #include "net/quic/quic_data_reader.h"
 #include "net/quic/quic_data_writer.h"
 
@@ skipping 190 matching lines @@
 
   switch (state_) {
     case STATE_READING_TAG:
       if (reader.BytesRemaining() < kQuicTagSize) {
         break;
       }
       QuicTag message_tag;
       reader.ReadUInt32(&message_tag);
       message_.set_tag(message_tag);
       state_ = STATE_READING_NUM_ENTRIES;
+      FALLTHROUGH_INTENDED;
     case STATE_READING_NUM_ENTRIES:
       if (reader.BytesRemaining() < kNumEntriesSize + sizeof(uint16)) {
         break;
       }
       reader.ReadUInt16(&num_entries_);
       if (num_entries_ > kMaxEntries) {
         return QUIC_CRYPTO_TOO_MANY_ENTRIES;
       }
       uint16 padding;
       reader.ReadUInt16(&padding);
 
       tags_and_lengths_.reserve(num_entries_);
       state_ = STATE_READING_TAGS_AND_LENGTHS;
       values_len_ = 0;
+      FALLTHROUGH_INTENDED;
     case STATE_READING_TAGS_AND_LENGTHS: {
       if (reader.BytesRemaining() <
               num_entries_ * (kQuicTagSize + kCryptoEndOffsetSize)) {
         break;
       }
 
       uint32 last_end_offset = 0;
       for (unsigned i = 0; i < num_entries_; ++i) {
         QuicTag tag;
         reader.ReadUInt32(&tag);
         if (i > 0 && tag <= tags_and_lengths_[i-1].first) {
           if (tag == tags_and_lengths_[i-1].first) {
             return QUIC_CRYPTO_DUPLICATE_TAG;
           }
           return QUIC_CRYPTO_TAGS_OUT_OF_ORDER;
         }
 
         uint32 end_offset;
         reader.ReadUInt32(&end_offset);
 
         if (end_offset < last_end_offset) {
           return QUIC_CRYPTO_TAGS_OUT_OF_ORDER;
         }
         tags_and_lengths_.push_back(
             make_pair(tag, static_cast<size_t>(end_offset - last_end_offset)));
         last_end_offset = end_offset;
       }
       values_len_ = last_end_offset;
       state_ = STATE_READING_VALUES;
+      FALLTHROUGH_INTENDED;
     }
     case STATE_READING_VALUES:
       if (reader.BytesRemaining() < values_len_) {
         break;
       }
       for (vector<pair<QuicTag, size_t> >::const_iterator
            it = tags_and_lengths_.begin(); it != tags_and_lengths_.end();
            it++) {
         StringPiece value;
         reader.ReadStringPiece(&value, it->second);
@@ skipping 19 matching lines @@
   }
   *end_offset += pad_length;
   if (!writer->WriteUInt32(*end_offset)) {
     DCHECK(false) << "Failed to write end offset.";
     return false;
   }
   return true;
 }
 
 }  // namespace net