Rent-A-Codec: Reference count the shared iSAC bandwidth estimation state

Now that the Rent-A-Codec no longer owns the encoders and decoders it
produces, they may outlive it. It's thus no longer correct for the
Rent-A-Codec to own the bandwidth estimation state; all of the
involved objects need to share ownership.

BUG=webrtc:5028

Review URL: https://codereview.webrtc.org/1821513003

Cr-Commit-Position: refs/heads/master@{#12159}

webrtc/modules/audio_coding/codecs/isac/audio_decoder_isac_t.h

@@ -13,6 +13,7 @@
 
 #include <vector>
 
+#include "webrtc/base/scoped_ref_ptr.h"
 #include "webrtc/modules/audio_coding/codecs/audio_decoder.h"
 #include "webrtc/modules/audio_coding/codecs/isac/locked_bandwidth_info.h"
 
@@ -22,7 +23,8 @@ template <typename T>
 class AudioDecoderIsacT final : public AudioDecoder {
  public:
   AudioDecoderIsacT();
-  explicit AudioDecoderIsacT(LockedIsacBandwidthInfo* bwinfo);
+  explicit AudioDecoderIsacT(
+      const rtc::scoped_refptr<LockedIsacBandwidthInfo>& bwinfo);
   ~AudioDecoderIsacT() override;
 
   bool HasDecodePlc() const override;
@@ -43,7 +45,7 @@ class AudioDecoderIsacT final : public AudioDecoder {
 
  private:
   typename T::instance_type* isac_state_;
-  LockedIsacBandwidthInfo* bwinfo_;
+  rtc::scoped_refptr<LockedIsacBandwidthInfo> bwinfo_;
   int decoder_sample_rate_hz_;
 
   RTC_DISALLOW_COPY_AND_ASSIGN(AudioDecoderIsacT);

webrtc/modules/audio_coding/codecs/isac/audio_decoder_isac_t_impl.h

@@ -22,7 +22,8 @@ AudioDecoderIsacT<T>::AudioDecoderIsacT()
     : AudioDecoderIsacT(nullptr) {}
 
 template <typename T>
-AudioDecoderIsacT<T>::AudioDecoderIsacT(LockedIsacBandwidthInfo* bwinfo)
+AudioDecoderIsacT<T>::AudioDecoderIsacT(
+    const rtc::scoped_refptr<LockedIsacBandwidthInfo>& bwinfo)
     : bwinfo_(bwinfo), decoder_sample_rate_hz_(-1) {
   RTC_CHECK_EQ(0, T::Create(&isac_state_));
   T::DecoderInit(isac_state_);

webrtc/modules/audio_coding/codecs/isac/audio_encoder_isac_t.h

@@ -13,6 +13,7 @@
 
 #include <vector>
 
+#include "webrtc/base/scoped_ref_ptr.h"
 #include "webrtc/modules/audio_coding/codecs/audio_encoder.h"
 #include "webrtc/modules/audio_coding/codecs/isac/locked_bandwidth_info.h"
 
@@ -30,7 +31,7 @@ class AudioEncoderIsacT final : public AudioEncoder {
   struct Config {
     bool IsOk() const;
 
-    LockedIsacBandwidthInfo* bwinfo = nullptr;
+    rtc::scoped_refptr<LockedIsacBandwidthInfo> bwinfo;
 
     int payload_type = 103;
     int sample_rate_hz = 16000;
@@ -50,8 +51,9 @@ class AudioEncoderIsacT final : public AudioEncoder {
   };
 
   explicit AudioEncoderIsacT(const Config& config);
-  explicit AudioEncoderIsacT(const CodecInst& codec_inst,
-                             LockedIsacBandwidthInfo* bwinfo);
+  explicit AudioEncoderIsacT(
+      const CodecInst& codec_inst,
+      const rtc::scoped_refptr<LockedIsacBandwidthInfo>& bwinfo);
   ~AudioEncoderIsacT() override;
 
   size_t MaxEncodedBytes() const override;
@@ -77,7 +79,7 @@ class AudioEncoderIsacT final : public AudioEncoder {
 
   Config config_;
   typename T::instance_type* isac_state_ = nullptr;
-  LockedIsacBandwidthInfo* bwinfo_ = nullptr;
+  rtc::scoped_refptr<LockedIsacBandwidthInfo> bwinfo_;
 
   // Have we accepted input but not yet emitted it in a packet?
   bool packet_in_progress_ = false;

webrtc/modules/audio_coding/codecs/isac/audio_encoder_isac_t_impl.h

@@ -21,7 +21,7 @@ namespace webrtc {
 template <typename T>
 typename AudioEncoderIsacT<T>::Config CreateIsacConfig(
     const CodecInst& codec_inst,
-    LockedIsacBandwidthInfo* bwinfo) {
+    const rtc::scoped_refptr<LockedIsacBandwidthInfo>& bwinfo) {
   typename AudioEncoderIsacT<T>::Config config;
   config.bwinfo = bwinfo;
   config.payload_type = codec_inst.pltype;
@@ -69,8 +69,9 @@ AudioEncoderIsacT<T>::AudioEncoderIsacT(const Config& config) {
 }
 
 template <typename T>
-AudioEncoderIsacT<T>::AudioEncoderIsacT(const CodecInst& codec_inst,
-                                        LockedIsacBandwidthInfo* bwinfo)
+AudioEncoderIsacT<T>::AudioEncoderIsacT(
+    const CodecInst& codec_inst,
+    const rtc::scoped_refptr<LockedIsacBandwidthInfo>& bwinfo)
     : AudioEncoderIsacT(CreateIsacConfig<T>(codec_inst, bwinfo)) {}
 
 template <typename T>

webrtc/modules/audio_coding/codecs/isac/locked_bandwidth_info.cc

@@ -12,7 +12,7 @@
 
 namespace webrtc {
 
-LockedIsacBandwidthInfo::LockedIsacBandwidthInfo() {
+LockedIsacBandwidthInfo::LockedIsacBandwidthInfo() : ref_count_(0) {
   bwinfo_.in_use = 0;
 }
 

webrtc/modules/audio_coding/codecs/isac/locked_bandwidth_info.h

@@ -11,6 +11,7 @@
 #ifndef WEBRTC_MODULES_AUDIO_CODING_CODECS_ISAC_LOCKED_BANDWIDTH_INFO_H_
 #define WEBRTC_MODULES_AUDIO_CODING_CODECS_ISAC_LOCKED_BANDWIDTH_INFO_H_
 
+#include "webrtc/base/atomicops.h"
 #include "webrtc/base/criticalsection.h"
 #include "webrtc/base/thread_annotations.h"
 #include "webrtc/modules/audio_coding/codecs/isac/bandwidth_info.h"
@@ -34,7 +35,18 @@ class LockedIsacBandwidthInfo final {
     bwinfo_ = bwinfo;
   }
 
+  int AddRef() const { return rtc::AtomicOps::Increment(&ref_count_); }
+
+  int Release() const {
+    const int count = rtc::AtomicOps::Decrement(&ref_count_);
+    if (count == 0) {
+      delete this;
+    }
+    return count;
+  }
+
  private:
+  mutable volatile int ref_count_;
   rtc::CriticalSection lock_;
   IsacBandwidthInfo bwinfo_ GUARDED_BY(lock_);
 };