1 files changed, 168 insertions, 0 deletions
diff --git a/webrtc/video/call_stats.cc b/webrtc/video/call_stats.cc
new file mode 100644
index 0000000000..69ea1a3d78
--- /dev/null
+++ b/webrtc/video/call_stats.cc
@@ -0,0 +1,168 @@
+/*
+ *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "webrtc/video/call_stats.h"
+
+#include <assert.h>
+
+#include <algorithm>
+
+#include "webrtc/modules/rtp_rtcp/include/rtp_rtcp_defines.h"
+#include "webrtc/system_wrappers/include/critical_section_wrapper.h"
+#include "webrtc/system_wrappers/include/tick_util.h"
+
+namespace webrtc {
+namespace {
+// Time interval for updating the observers.
+const int64_t kUpdateIntervalMs = 1000;
+// Weight factor to apply to the average rtt.
+const float kWeightFactor = 0.3f;
+
+void RemoveOldReports(int64_t now, std::list<CallStats::RttTime>* reports) {
+  // A rtt report is considered valid for this long.
+  const int64_t kRttTimeoutMs = 1500;
+  while (!reports->empty() &&
+         (now - reports->front().time) > kRttTimeoutMs) {
+    reports->pop_front();
+  }
+}
+
+int64_t GetMaxRttMs(std::list<CallStats::RttTime>* reports) {
+  int64_t max_rtt_ms = 0;
+  for (std::list<CallStats::RttTime>::const_iterator it = reports->begin();
+       it != reports->end(); ++it) {
+    max_rtt_ms = std::max(it->rtt, max_rtt_ms);
+  }
+  return max_rtt_ms;
+}
+
+int64_t GetAvgRttMs(std::list<CallStats::RttTime>* reports) {
+  if (reports->empty()) {
+    return 0;
+  }
+  int64_t sum = 0;
+  for (std::list<CallStats::RttTime>::const_iterator it = reports->begin();
+       it != reports->end(); ++it) {
+    sum += it->rtt;
+  }
+  return sum / reports->size();
+}
+
+void UpdateAvgRttMs(std::list<CallStats::RttTime>* reports, int64_t* avg_rtt) {
+  uint32_t cur_rtt_ms = GetAvgRttMs(reports);
+  if (cur_rtt_ms == 0) {
+    // Reset.
+    *avg_rtt = 0;
+    return;
+  }
+  if (*avg_rtt == 0) {
+    // Initialize.
+    *avg_rtt = cur_rtt_ms;
+    return;
+  }
+  *avg_rtt = *avg_rtt * (1.0f - kWeightFactor) + cur_rtt_ms * kWeightFactor;
+}
+}  // namespace
+
+class RtcpObserver : public RtcpRttStats {
+ public:
+  explicit RtcpObserver(CallStats* owner) : owner_(owner) {}
+  virtual ~RtcpObserver() {}
+
+  virtual void OnRttUpdate(int64_t rtt) {
+    owner_->OnRttUpdate(rtt);
+  }
+
+  // Returns the average RTT.
+  virtual int64_t LastProcessedRtt() const {
+    return owner_->avg_rtt_ms();
+  }
+
+ private:
+  CallStats* owner_;
+
+  RTC_DISALLOW_COPY_AND_ASSIGN(RtcpObserver);
+};
+
+CallStats::CallStats(Clock* clock)
+    : clock_(clock),
+      crit_(CriticalSectionWrapper::CreateCriticalSection()),
+      rtcp_rtt_stats_(new RtcpObserver(this)),
+      last_process_time_(clock_->TimeInMilliseconds()),
+      max_rtt_ms_(0),
+      avg_rtt_ms_(0) {}
+
+CallStats::~CallStats() {
+  assert(observers_.empty());
+}
+
+int64_t CallStats::TimeUntilNextProcess() {
+  return last_process_time_ + kUpdateIntervalMs - clock_->TimeInMilliseconds();
+}
+
+int32_t CallStats::Process() {
+  CriticalSectionScoped cs(crit_.get());
+  int64_t now = clock_->TimeInMilliseconds();
+  if (now < last_process_time_ + kUpdateIntervalMs)
+    return 0;
+
+  last_process_time_ = now;
+
+  RemoveOldReports(now, &reports_);
+  max_rtt_ms_ = GetMaxRttMs(&reports_);
+  UpdateAvgRttMs(&reports_, &avg_rtt_ms_);
+
+  // If there is a valid rtt, update all observers with the max rtt.
+  // TODO(asapersson): Consider changing this to report the average rtt.
+  if (max_rtt_ms_ > 0) {
+    for (std::list<CallStatsObserver*>::iterator it = observers_.begin();
+         it != observers_.end(); ++it) {
+      (*it)->OnRttUpdate(avg_rtt_ms_, max_rtt_ms_);
+    }
+  }
+  return 0;
+}
+
+int64_t CallStats::avg_rtt_ms() const {
+  CriticalSectionScoped cs(crit_.get());
+  return avg_rtt_ms_;
+}
+
+RtcpRttStats* CallStats::rtcp_rtt_stats() const {
+  return rtcp_rtt_stats_.get();
+}
+
+void CallStats::RegisterStatsObserver(CallStatsObserver* observer) {
+  CriticalSectionScoped cs(crit_.get());
+  for (std::list<CallStatsObserver*>::iterator it = observers_.begin();
+       it != observers_.end(); ++it) {
+    if (*it == observer)
+      return;
+  }
+  observers_.push_back(observer);
+}
+
+void CallStats::DeregisterStatsObserver(CallStatsObserver* observer) {
+  CriticalSectionScoped cs(crit_.get());
+  for (std::list<CallStatsObserver*>::iterator it = observers_.begin();
+       it != observers_.end(); ++it) {
+    if (*it == observer) {
+      observers_.erase(it);
+      return;
+    }
+  }
+}
+
+void CallStats::OnRttUpdate(int64_t rtt) {
+  CriticalSectionScoped cs(crit_.get());
+  reports_.push_back(RttTime(rtt, clock_->TimeInMilliseconds()));
+}
+
+}  // namespace webrtc