Cap the memory usage in FFMpegDemuxer.

media/filters/ffmpeg_demuxer.cc

Index: media/filters/ffmpeg_demuxer.cc
diff --git a/media/filters/ffmpeg_demuxer.cc b/media/filters/ffmpeg_demuxer.cc
index 0dec8b8822229cadc076436b04304c0209a1fbfb..db9d3d62a08f19b95f0a12ee78b52088470838d2 100644
--- a/media/filters/ffmpeg_demuxer.cc
+++ b/media/filters/ffmpeg_demuxer.cc
@@ -5,6 +5,7 @@
 #include "media/filters/ffmpeg_demuxer.h"
 
 #include <algorithm>
+#include <limits>
 #include <string>
 
 #include "base/base64.h"
@@ -323,6 +324,10 @@ bool FFmpegDemuxerStream::HasAvailableCapacity() {
   return buffer_queue_.IsEmpty() || buffer_queue_.Duration() < kCapacity;
 }
 
+int FFmpegDemuxerStream::MemoryUsage() const {
+  return buffer_queue_.data_size();
+}
+
 TextKind FFmpegDemuxerStream::GetTextKind() const {
   DCHECK_EQ(type_, DemuxerStream::TEXT);
 
@@ -800,7 +805,10 @@ void FFmpegDemuxer::OnReadFrameDone(ScopedAVPacket packet, int result) {
     return;
   }
 
-  if (result < 0) {
+  // Consider the stream as ended if:
+  // - either underlying ffmpeg returned an error
+  // - or FFMpegDemuxer reached the maximum allowed memory usage.
+  if (result < 0 || IsMaxMemoryReached()) {
     // Update the duration based on the highest elapsed time across all streams
     // if it was previously unknown.
     if (!duration_known_) {
@@ -907,6 +915,23 @@ bool FFmpegDemuxer::StreamsHaveAvailableCapacity() {
   return false;
 }
 
+bool FFmpegDemuxer::IsMaxMemoryReached() {

[damienv1, 2014/02/19 00:15:09]

Better design: have a MemoryUsage function (just like we have a MemoryUsage in
FFMpegDemuxerStream), do not compare against the memory limit here.

[damienv1, 2014/02/19 00:27:13]

Done.

+  DCHECK(task_runner_->BelongsToCurrentThread());
+  // Max allowed memory usage, all streams combined.
+  const int kMemoryLimit = 150 * 1024 * 1024;
+  int memory_usage = 0;
+  StreamVector::iterator iter;

[damienv1, 2014/02/19 00:27:13]

To be removed (already in the for loop).

+  for (StreamVector::iterator iter = streams_.begin();
+       iter != streams_.end(); ++iter) {
+    if (!(*iter))
+      continue;
+    DCHECK_LE((*iter)->MemoryUsage(),
+              std::numeric_limits<int>::max() - memory_usage);
+    memory_usage += (*iter)->MemoryUsage();

[acolwell GONE FROM CHROMIUM, 2014/02/18 23:57:49]

nit: I'm a little more worried about overflow here. How about we track
memory_free instead of memory_usage and early return if ((*iter)->MemoryUsage()
> memory_free). I think that might be a little safer.

[damienv1, 2014/02/19 00:27:13]

I was a bit worried as well. So I agree and I am going to add a condition
instead of a DCHECK.

+  }
+  return (memory_usage >= kMemoryLimit);
+}
+
 void FFmpegDemuxer::StreamHasEnded() {
   DCHECK(task_runner_->BelongsToCurrentThread());
   StreamVector::iterator iter;