Add RSID-based demuxing to RtpDemuxer

webrtc/common_types.cc

Index: webrtc/common_types.cc
diff --git a/webrtc/common_types.cc b/webrtc/common_types.cc
index b9c4737aeb511627bd1b3697269ef047d8a11ad1..961dd6f15921a0ac8ea58b34089b4068f97aa3b4 100644
--- a/webrtc/common_types.cc
+++ b/webrtc/common_types.cc
@@ -11,6 +11,7 @@
 #include "webrtc/common_types.h"
 
 #include <string.h>
+#include <algorithm>
 #include <limits>
 #include <type_traits>
 
@@ -23,9 +24,14 @@ StreamDataCounters::StreamDataCounters() : first_packet_time_ms(-1) {}
 
 constexpr size_t StreamId::kMaxSize;
 
+bool StreamId::IsLegalName(const char* data, size_t size) {
+  return (size <= kMaxSize && size > 0 &&
+          std::all_of(data, data + size, isalnum));

[danilchap, 2017/06/02 17:42:20]

may be remove () around the expression.
https://google.github.io/styleguide/cppguide.html#Return_Values

[eladalon, 2017/06/02 19:44:05]

That link seems to suggest that the parenthesis are in fact okay in here.

[danilchap, 2017/06/07 13:45:41]

yep, in this case it is ok, thus 'may be'

+}
+
 void StreamId::Set(const char* data, size_t size) {
   // If |data| contains \0, the stream id size might become less than |size|.
-  RTC_DCHECK_LE(size, kMaxSize);
+  RTC_DCHECK_LE(size, kMaxSize);  // TODO(eladalon): IsLegalName?

[danilchap, 2017/06/02 17:42:20]

probably not:
Set is called by parser too. While parser should guarantee the size, it doesn't
check if name isalnum.
of-course it can't guarantee that other side put only allowed characters into
the buffer.

[eladalon, 2017/06/02 19:44:05]

My intention with this TODO is to come back to this at a later CL and change the
CHECK_LE into a CHECK(IsLegalName()), after the necessary extra work has been
done - making sure anyone who could call StreamId would fail gracefully instead
of calling StreamId() with a disallowed RSID. Wdyt?

[danilchap, 2017/06/07 13:45:41]

I prefer to think about StreamId as a special implementation of string (and
eventually plan to replace all uses of it by string) so prefer to put as little
as possible extra logic in it.

As for users of the StreamId - I do not think it would be benefitial to
check(IsLegalName()) when receiving a packet - illegal names will be discarded
automatically when compared to configured legal names.

   memcpy(value_, data, size);
   if (size < kMaxSize)
     value_[size] = 0;