Moved DCHECK() to prevent NULL deref of codec_context_.

media/filters/audio_file_reader.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 "media/filters/audio_file_reader.h"
 
 #include <string>
 #include "base/basictypes.h"
 #include "base/string_util.h"
 #include "base/time.h"
@@ skipping 94 matching lines @@
   codec_ = NULL;
 
   if (format_context_) {
     avformat_close_input(&format_context_);
     format_context_ = NULL;
   }
 }
 
 bool AudioFileReader::Read(const std::vector<float*>& audio_data,
                            size_t number_of_frames) {
+  DCHECK(format_context_ && codec_context_ && codec_);
+
   size_t channels = this->channels();
   DCHECK_EQ(audio_data.size(), channels);
   if (audio_data.size() != channels)
     return false;
 
-  DCHECK(format_context_ && codec_context_ && codec_);
   if (!format_context_ || !codec_context_ || !codec_) {

[Tyler Breisacher (Chromium), 2012/07/25 21:53:03]

Isn't if () redundant then? Maybe it should just say:

DCHECK(format_context_ && codec_context_ && codec_) << "AudioFileReader::Read()
: reader is not opened!";

[Kyle Horimoto, 2012/07/25 21:57:25]

If we did that, we wouldn't hit the "return false;". Don't think we should be
changing the behavior in this case.

[Tyler Breisacher (Chromium), 2012/07/25 22:14:23]

The DCHECK is saying "none of these should ever be null" and this line is saying
"if one of these is null, then do the following". Check with someone who knows
this file better, to determine whether this is something that should NEVER
happen, or not.

     DLOG(WARNING) << "AudioFileReader::Read() : reader is not opened!";
     return false;
   }
 
   // Holds decoded audio.
   scoped_ptr_malloc<AVFrame, ScopedPtrAVFree> av_frame(avcodec_alloc_frame());
 
   // Read until we hit EOF or we've read the requested number of frames.
   AVPacket packet;
   int result = 0;
@@ skipping 46 matching lines @@
       }
     }
 
     current_frame += frames_read;
   }
 
   return true;
 }
 
 }  // namespace media