Refactor before implementing per stream suspension.

webrtc/call/bitrate_allocator.cc

 /*
  *  Copyright (c) 2015 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/call/bitrate_allocator.h"
 
 #include <algorithm>
 #include <utility>
 
+#include "webrtc/base/checks.h"
 #include "webrtc/modules/bitrate_controller/include/bitrate_controller.h"
 
 namespace webrtc {
 
 // Allow packets to be transmitted in up to 2 times max video bitrate if the
 // bandwidth estimate allows it.
 const int kTransmissionMaxBitrateMultiplier = 2;
 const int kDefaultBitrateBps = 300000;
 
 BitrateAllocator::BitrateAllocator()
-    : bitrate_observers_(),
-      bitrate_observers_modified_(false),
+    : bitrate_observer_configs_(),
       enforce_min_bitrate_(true),
       last_bitrate_bps_(kDefaultBitrateBps),
       last_fraction_loss_(0),
       last_rtt_(0) {}
 
 uint32_t BitrateAllocator::OnNetworkChanged(uint32_t bitrate,
                                             uint8_t fraction_loss,
                                             int64_t rtt) {
   rtc::CritScope lock(&crit_sect_);
   last_bitrate_bps_ = bitrate;
   last_fraction_loss_ = fraction_loss;
   last_rtt_ = rtt;
+
   uint32_t allocated_bitrate_bps = 0;
-  ObserverBitrateMap allocation = AllocateBitrates();
+  ObserverAllocation allocation = AllocateBitrates();
   for (const auto& kv : allocation) {
     kv.first->OnBitrateUpdated(kv.second, last_fraction_loss_, last_rtt_);
     allocated_bitrate_bps += kv.second;
   }
   return allocated_bitrate_bps;
 }
 
-BitrateAllocator::ObserverBitrateMap BitrateAllocator::AllocateBitrates() {
-  if (bitrate_observers_.empty())
-    return ObserverBitrateMap();
-
-  uint32_t sum_min_bitrates = 0;
-  for (const auto& observer : bitrate_observers_)
-    sum_min_bitrates += observer.second.min_bitrate;
-  if (last_bitrate_bps_ == 0)
-    return ZeroRateAllocation();
-  else if (last_bitrate_bps_ <= sum_min_bitrates)
-    return LowRateAllocation(last_bitrate_bps_);
-  else
-    return NormalRateAllocation(last_bitrate_bps_, sum_min_bitrates);
-}
-
 int BitrateAllocator::AddObserver(BitrateAllocatorObserver* observer,
                                   uint32_t min_bitrate_bps,
-                                  uint32_t max_bitrate_bps) {
+                                  uint32_t max_bitrate_bps,
+                                  bool enforce_min_bitrate) {
   rtc::CritScope lock(&crit_sect_);
+  // TODO(mflodman): Enforce this per observer.
+  EnforceMinBitrate(enforce_min_bitrate);
 
-  BitrateObserverConfList::iterator it =
-      FindObserverConfigurationPair(observer);
+  auto it = FindObserverConfig(observer);
 
   // Allow the max bitrate to be exceeded for FEC and retransmissions.
   // TODO(holmer): We have to get rid of this hack as it makes it difficult to
   // properly allocate bitrate. The allocator should instead distribute any
   // extra bitrate after all streams have maxed out.
   max_bitrate_bps *= kTransmissionMaxBitrateMultiplier;
-  if (it != bitrate_observers_.end()) {
+  if (it != bitrate_observer_configs_.end()) {
     // Update current configuration.
-    it->second.min_bitrate = min_bitrate_bps;
-    it->second.max_bitrate = max_bitrate_bps;
+    it->min_bitrate_bps = min_bitrate_bps;
+    it->max_bitrate_bps = max_bitrate_bps;
   } else {
     // Add new settings.
-    bitrate_observers_.push_back(BitrateObserverConfiguration(
-        observer, BitrateConfiguration(min_bitrate_bps, max_bitrate_bps)));
-    bitrate_observers_modified_ = true;
+    bitrate_observer_configs_.push_back(ObserverConfig(
+        observer, min_bitrate_bps, max_bitrate_bps, enforce_min_bitrate));
   }
 
-  ObserverBitrateMap allocation = AllocateBitrates();
+  ObserverAllocation allocation = AllocateBitrates();
   int new_observer_bitrate_bps = 0;
   for (auto& kv : allocation) {
     kv.first->OnBitrateUpdated(kv.second, last_fraction_loss_, last_rtt_);
     if (kv.first == observer)
       new_observer_bitrate_bps = kv.second;
   }
   return new_observer_bitrate_bps;
 }
 
 void BitrateAllocator::RemoveObserver(BitrateAllocatorObserver* observer) {
   rtc::CritScope lock(&crit_sect_);
-  BitrateObserverConfList::iterator it =
-      FindObserverConfigurationPair(observer);
-  if (it != bitrate_observers_.end()) {
-    bitrate_observers_.erase(it);
-    bitrate_observers_modified_ = true;
+  auto it = FindObserverConfig(observer);
+  if (it != bitrate_observer_configs_.end()) {
+    bitrate_observer_configs_.erase(it);
   }
 }
 
-BitrateAllocator::BitrateObserverConfList::iterator
-BitrateAllocator::FindObserverConfigurationPair(
-    const BitrateAllocatorObserver* observer) {
-  for (auto it = bitrate_observers_.begin(); it != bitrate_observers_.end();
-       ++it) {
-    if (it->first == observer)
-      return it;
-  }
-  return bitrate_observers_.end();
-}
-
 void BitrateAllocator::EnforceMinBitrate(bool enforce_min_bitrate) {
-  rtc::CritScope lock(&crit_sect_);
   enforce_min_bitrate_ = enforce_min_bitrate;
 }
 
-BitrateAllocator::ObserverBitrateMap BitrateAllocator::NormalRateAllocation(
+BitrateAllocator::ObserverConfigList::iterator
+BitrateAllocator::FindObserverConfig(
+    const BitrateAllocatorObserver* observer) {
+  for (auto it = bitrate_observer_configs_.begin();
+       it != bitrate_observer_configs_.end(); ++it) {
+    if (it->observer == observer)
+      return it;
+  }
+  return bitrate_observer_configs_.end();
+}
+
+BitrateAllocator::ObserverAllocation BitrateAllocator::AllocateBitrates() {
+  if (bitrate_observer_configs_.empty())
+    return ObserverAllocation();
+
+  if (last_bitrate_bps_ == 0)
+    return ZeroRateAllocation();
+
+  uint32_t sum_min_bitrates = 0;
+  for (const auto& observer_config : bitrate_observer_configs_)
+    sum_min_bitrates += observer_config.min_bitrate_bps;
+  if (last_bitrate_bps_ <= sum_min_bitrates)
+    return LowRateAllocation(last_bitrate_bps_);
+
+  return NormalRateAllocation(last_bitrate_bps_, sum_min_bitrates);
+}
+
+BitrateAllocator::ObserverAllocation BitrateAllocator::NormalRateAllocation(
     uint32_t bitrate,
     uint32_t sum_min_bitrates) {
-  uint32_t number_of_observers =
-      static_cast<uint32_t>(bitrate_observers_.size());
+  uint32_t num_remaining_observers =
+      static_cast<uint32_t>(bitrate_observer_configs_.size());
+  RTC_DCHECK_GT(num_remaining_observers, 0u);
+
   uint32_t bitrate_per_observer =
-      (bitrate - sum_min_bitrates) / number_of_observers;
+      (bitrate - sum_min_bitrates) / num_remaining_observers;
   // Use map to sort list based on max bitrate.
   ObserverSortingMap list_max_bitrates;
-  for (const auto& observer : bitrate_observers_) {
-    list_max_bitrates.insert(std::pair<uint32_t, ObserverConfiguration>(
-        observer.second.max_bitrate,
-        ObserverConfiguration(observer.first, observer.second.min_bitrate)));
+  for (const auto& config : bitrate_observer_configs_) {
+    list_max_bitrates.insert(std::pair<uint32_t, const ObserverConfig*>(
+        config.max_bitrate_bps, &config));
   }
-  ObserverBitrateMap allocation;
+
+  ObserverAllocation allocation;
   ObserverSortingMap::iterator max_it = list_max_bitrates.begin();
   while (max_it != list_max_bitrates.end()) {
-    number_of_observers--;
+    num_remaining_observers--;
     uint32_t observer_allowance =
-        max_it->second.min_bitrate + bitrate_per_observer;
+        max_it->second->min_bitrate_bps + bitrate_per_observer;
     if (max_it->first < observer_allowance) {
       // We have more than enough for this observer.
       // Carry the remainder forward.
       uint32_t remainder = observer_allowance - max_it->first;
-      if (number_of_observers != 0) {
-        bitrate_per_observer += remainder / number_of_observers;
-      }
-      allocation[max_it->second.observer] = max_it->first;
+      if (num_remaining_observers != 0)
+        bitrate_per_observer += remainder / num_remaining_observers;
+      allocation[max_it->second->observer] = max_it->first;
     } else {
-      allocation[max_it->second.observer] = observer_allowance;
+      allocation[max_it->second->observer] = observer_allowance;
     }
     list_max_bitrates.erase(max_it);
     // Prepare next iteration.
     max_it = list_max_bitrates.begin();
   }
   return allocation;
 }
 
-BitrateAllocator::ObserverBitrateMap BitrateAllocator::ZeroRateAllocation() {
-  ObserverBitrateMap allocation;
+BitrateAllocator::ObserverAllocation BitrateAllocator::ZeroRateAllocation() {
+  ObserverAllocation allocation;
   // Zero bitrate to all observers.
-  for (const auto& observer : bitrate_observers_)
-    allocation[observer.first] = 0;
+  for (const auto& observer_config : bitrate_observer_configs_)
+    allocation[observer_config.observer] = 0;
   return allocation;
 }
 
-BitrateAllocator::ObserverBitrateMap BitrateAllocator::LowRateAllocation(
+BitrateAllocator::ObserverAllocation BitrateAllocator::LowRateAllocation(
     uint32_t bitrate) {
-  ObserverBitrateMap allocation;
+  ObserverAllocation allocation;
   if (enforce_min_bitrate_) {
     // Min bitrate to all observers.
-    for (const auto& observer : bitrate_observers_)
-      allocation[observer.first] = observer.second.min_bitrate;
+    for (const auto& observer_config : bitrate_observer_configs_)
+      allocation[observer_config.observer] = observer_config.min_bitrate_bps;
   } else {
-    // Allocate up to |min_bitrate| to one observer at a time, until
+    // Allocate up to |min_bitrate_bps| to one observer at a time, until
     // |bitrate| is depleted.
     uint32_t remainder = bitrate;
-    for (const auto& observer : bitrate_observers_) {
+    for (const auto& observer_config : bitrate_observer_configs_) {
       uint32_t allocated_bitrate =
-          std::min(remainder, observer.second.min_bitrate);
-      allocation[observer.first] = allocated_bitrate;
+          std::min(remainder, observer_config.min_bitrate_bps);
+      allocation[observer_config.observer] = allocated_bitrate;
       remainder -= allocated_bitrate;
     }
   }
   return allocation;
 }
 }  // namespace webrtc