Remove global list of SRTP sessions.

talk/session/media/srtpfilter.cc

Index: talk/session/media/srtpfilter.cc
diff --git a/talk/session/media/srtpfilter.cc b/talk/session/media/srtpfilter.cc
index 079ddfb57ee553474c2a42470c2de446d4b9c390..06ce7119ea39ef0db914141d2581890ddbf6b3fd 100644
--- a/talk/session/media/srtpfilter.cc
+++ b/talk/session/media/srtpfilter.cc
@@ -481,7 +481,7 @@ bool SrtpFilter::ParseKeyParams(const std::string& key_params,
 
 bool SrtpSession::inited_ = false;
 
-// This lock protects SrtpSession::inited_ and SrtpSession::sessions_.
+// This lock protects SrtpSession::inited_.
 rtc::GlobalLockPod SrtpSession::lock_;
 
 SrtpSession::SrtpSession()
@@ -490,19 +490,12 @@ SrtpSession::SrtpSession()
       rtcp_auth_tag_len_(0),
       srtp_stat_(new SrtpStat()),
       last_send_seq_num_(-1) {
-  {
-    rtc::GlobalLockScope ls(&lock_);
-    sessions()->push_back(this);
-  }
   SignalSrtpError.repeat(srtp_stat_->SignalSrtpError);
 }
 
 SrtpSession::~SrtpSession() {
-  {
-    rtc::GlobalLockScope ls(&lock_);
-    sessions()->erase(std::find(sessions()->begin(), sessions()->end(), this));
-  }
   if (session_) {
+    session_->user_data = nullptr;
     srtp_dealloc(session_);
   }
 }
@@ -717,7 +710,7 @@ bool SrtpSession::SetKey(int type,
     return false;
   }
 
-
+  session_->user_data = this;
   rtp_auth_tag_len_ = policy.rtp.auth_tag_len;
   rtcp_auth_tag_len_ = policy.rtcp.auth_tag_len;
   return true;
@@ -786,22 +779,12 @@ void SrtpSession::HandleEvent(const srtp_event_data_t* ev) {
 }
 
 void SrtpSession::HandleEventThunk(srtp_event_data_t* ev) {
-  rtc::GlobalLockScope ls(&lock_);
-
-  for (std::list<SrtpSession*>::iterator it = sessions()->begin();
-       it != sessions()->end(); ++it) {
-    if ((*it)->session_ == ev->session) {
-      (*it)->HandleEvent(ev);
-      break;
-    }
+  SrtpSession* session = static_cast<SrtpSession*>(ev->session->user_data);

[juberti, 2015/11/10 01:25:59]

Do we know what thread this gets invoked from? Would be good to document it to
ensure proper locking.

[joachim, 2015/11/10 16:59:56]

Done.

+  if (session) {
+    session->HandleEvent(ev);
   }
 }
 
-std::list<SrtpSession*>* SrtpSession::sessions() {
-  RTC_DEFINE_STATIC_LOCAL(std::list<SrtpSession*>, sessions, ());
-  return &sessions;
-}
-
 #else   // !HAVE_SRTP
 
 // On some systems, SRTP is not (yet) available.