Constructor initialization and const fields

In constructors, initialize member fields in the initialization list
rather than constructor body where possible.  This allows more fields
to be const, provided they are never modified.

Also initialize POD fields in constructor, unless it's obvious they
don't need to be initialized.  In that case, put a comment instead.

Remove explicit clear() in destructors on fields that are now const.

Give AudioSessionRef a default constructor, so it's immutable fields can
be marked const.

Add comment about ~TrackBase() trick.

Initialize fields in declaration order to make it easier to confirm that
all fields are set.

Move initialization of mHardwareStatus from onFirstRef() to constructor.

Use NULL not 0 to initialize raw pointers in initialization list.

Rename field mClient to mAudioFlingerClient, and getter from client()
to audioFlingerClient().

Change-Id: Ib36cf6ed32f3cd19003f40a5d84046eb4c122052

3 files changed, 72 insertions, 53 deletions

diff --git a/services/audioflinger/AudioFlinger.cpp b/services/audioflinger/AudioFlinger.cpp
index a43afacff0e3..7d87d92c24f6 100644
--- a/services/audioflinger/AudioFlinger.cpp
+++ b/services/audioflinger/AudioFlinger.cpp
@@ -160,7 +160,10 @@ static const char * const audio_interfaces[] = {
 
 AudioFlinger::AudioFlinger()
     : BnAudioFlinger(),
-        mPrimaryHardwareDev(NULL), mMasterVolume(1.0f), mMasterMute(false), mNextUniqueId(1),
+        mPrimaryHardwareDev(NULL),
+        mHardwareStatus(AUDIO_HW_IDLE), // see also onFirstRef()
+        mMasterVolume(1.0f), mMasterMute(false), mNextUniqueId(1),
+        mMode(AUDIO_MODE_INVALID),
         mBtNrecIsOff(false)
 {
 }
@@ -172,7 +175,6 @@ void AudioFlinger::onFirstRef()
     Mutex::Autolock _l(mLock);
 
     /* TODO: move all this work into an Init() function */
-    mHardwareStatus = AUDIO_HW_IDLE;
 
     for (size_t i = 0; i < ARRAY_SIZE(audio_interfaces); i++) {
         const hw_module_t *mod;
@@ -971,7 +973,8 @@ void AudioFlinger::audioConfigChanged_l(int event, int ioHandle, void *param2)
 {
     size_t size = mNotificationClients.size();
     for (size_t i = 0; i < size; i++) {
-        mNotificationClients.valueAt(i)->client()->ioConfigChanged(event, ioHandle, param2);
+        mNotificationClients.valueAt(i)->audioFlingerClient()->ioConfigChanged(event, ioHandle,
+                                                                               param2);
     }
 }
 
@@ -989,11 +992,15 @@ AudioFlinger::ThreadBase::ThreadBase(const sp<AudioFlinger>& audioFlinger, int i
         type_t type)
     :   Thread(false),
         mType(type),
-        mAudioFlinger(audioFlinger), mSampleRate(0), mFrameCount(0), mChannelCount(0),
-        mFrameSize(1), mFormat(AUDIO_FORMAT_INVALID), mStandby(false), mId(id), mExiting(false),
-        mDevice(device)
+        mAudioFlinger(audioFlinger), mSampleRate(0), mFrameCount(0),
+        // mChannelMask
+        mChannelCount(0),
+        mFrameSize(1), mFormat(AUDIO_FORMAT_INVALID),
+        mParamStatus(NO_ERROR),
+        mStandby(false), mId(id), mExiting(false),
+        mDevice(device),
+        mDeathRecipient(new PMDeathRecipient(this))
 {
-    mDeathRecipient = new PMDeathRecipient(this);
 }
 
 AudioFlinger::ThreadBase::~ThreadBase()
@@ -1377,18 +1384,21 @@ AudioFlinger::PlaybackThread::PlaybackThread(const sp<AudioFlinger>& audioFlinge
                                              uint32_t device,
                                              type_t type)
     :   ThreadBase(audioFlinger, id, device, type),
-        mMixBuffer(NULL), mSuspended(0), mBytesWritten(0), mOutput(output),
+        mMixBuffer(NULL), mSuspended(0), mBytesWritten(0),
+        // Assumes constructor is called by AudioFlinger with it's mLock held,
+        // but it would be safer to explicitly pass initial masterMute as parameter
+        mMasterMute(audioFlinger->masterMute_l()),
+        // mStreamTypes[] initialized in constructor body
+        mOutput(output),
+        // Assumes constructor is called by AudioFlinger with it's mLock held,
+        // but it would be safer to explicitly pass initial masterVolume as parameter
+        mMasterVolume(audioFlinger->masterVolume_l()),
         mLastWriteTime(0), mNumWrites(0), mNumDelayedWrites(0), mInWrite(false)
 {
     snprintf(mName, kNameLength, "AudioOut_%d", id);
 
     readOutputParameters();
 
-    // Assumes constructor is called by AudioFlinger with it's mLock held,
-    // but it would be safer to explicitly pass these as parameters
-    mMasterVolume = mAudioFlinger->masterVolume_l();
-    mMasterMute = mAudioFlinger->masterMute_l();
-
     // mStreamTypes[AUDIO_STREAM_CNT] is initialized by stream_type_t default constructor
     // There is no AUDIO_STREAM_MIN, and ++ operator does not compile
     for (audio_stream_type_t stream = (audio_stream_type_t) 0; stream < AUDIO_STREAM_CNT;
@@ -1851,10 +1861,9 @@ uint32_t AudioFlinger::PlaybackThread::activeSleepTimeUs()
 AudioFlinger::MixerThread::MixerThread(const sp<AudioFlinger>& audioFlinger, AudioStreamOut* output,
         int id, uint32_t device, type_t type)
     :   PlaybackThread(audioFlinger, output, id, device, type),
-        mAudioMixer(NULL), mPrevMixerStatus(MIXER_IDLE)
+        mAudioMixer(new AudioMixer(mFrameCount, mSampleRate)),
+        mPrevMixerStatus(MIXER_IDLE)
 {
-    mAudioMixer = new AudioMixer(mFrameCount, mSampleRate);
-
     // FIXME - Current mixer implementation only supports stereo output
     if (mChannelCount == 1) {
         ALOGE("Invalid audio hardware channel count");
@@ -2519,6 +2528,8 @@ uint32_t AudioFlinger::MixerThread::suspendSleepTimeUs()
 // ----------------------------------------------------------------------------
 AudioFlinger::DirectOutputThread::DirectOutputThread(const sp<AudioFlinger>& audioFlinger, AudioStreamOut* output, int id, uint32_t device)
     :   PlaybackThread(audioFlinger, output, id, device, DIRECT)
+        // mLeftVolFloat, mRightVolFloat
+        // mLeftVolShort, mRightVolShort
 {
 }
 
@@ -3249,13 +3260,17 @@ AudioFlinger::ThreadBase::TrackBase::TrackBase(
     :   RefBase(),
         mThread(thread),
         mClient(client),
-        mCblk(0),
+        mCblk(NULL),
+        // mBuffer
+        // mBufferEnd
         mFrameCount(0),
         mState(IDLE),
         mClientTid(-1),
         mFormat(format),
         mFlags(flags & ~SYSTEM_FLAGS_MASK),
         mSessionId(sessionId)
+        // mChannelCount
+        // mChannelMask
 {
     ALOGV_IF(sharedBuffer != 0, "sharedBuffer: %p, size: %d", sharedBuffer->pointer(), sharedBuffer->size());
 
@@ -3322,6 +3337,7 @@ AudioFlinger::ThreadBase::TrackBase::~TrackBase()
     }
     mCblkMemory.clear();            // and free the shared memory
     if (mClient != NULL) {
+        // Client destructor must run with AudioFlinger mutex locked
         Mutex::Autolock _l(mClient->audioFlinger()->mLock);
         mClient.clear();
     }
@@ -4079,13 +4095,12 @@ sp<MemoryDealer> AudioFlinger::Client::heap() const
 AudioFlinger::NotificationClient::NotificationClient(const sp<AudioFlinger>& audioFlinger,
                                                      const sp<IAudioFlingerClient>& client,
                                                      pid_t pid)
-    : mAudioFlinger(audioFlinger), mPid(pid), mClient(client)
+    : mAudioFlinger(audioFlinger), mPid(pid), mAudioFlingerClient(client)
 {
 }
 
 AudioFlinger::NotificationClient::~NotificationClient()
 {
-    mClient.clear();
 }
 
 void AudioFlinger::NotificationClient::binderDied(const wp<IBinder>& who)
@@ -4271,12 +4286,15 @@ AudioFlinger::RecordThread::RecordThread(const sp<AudioFlinger>& audioFlinger,
                                          int id,
                                          uint32_t device) :
     ThreadBase(audioFlinger, id, device, RECORD),
-    mInput(input), mTrack(NULL), mResampler(NULL), mRsmpOutBuffer(NULL), mRsmpInBuffer(NULL)
+    mInput(input), mTrack(NULL), mResampler(NULL), mRsmpOutBuffer(NULL), mRsmpInBuffer(NULL),
+    // mRsmpInIndex and mInputBytes set by readInputParameters()
+    mReqChannelCount(popcount(channels)),
+    mReqSampleRate(sampleRate)
+    // mBytesRead is only meaningful while active, and so is cleared in start()
+    // (but might be better to also clear here for dump?)
 {
     snprintf(mName, kNameLength, "AudioIn_%d", id);
 
-    mReqChannelCount = popcount(channels);
-    mReqSampleRate = sampleRate;
     readInputParameters();
 }
 
@@ -5245,12 +5263,8 @@ void AudioFlinger::acquireAudioSessionId(int audioSession)
             return;
         }
     }
-    AudioSessionRef *ref = new AudioSessionRef();
-    ref->sessionid = audioSession;
-    ref->pid = caller;
-    ref->cnt = 1;
-    mAudioSessionRefs.push(ref);
-    ALOGV(" added new entry for %d", ref->sessionid);
+    mAudioSessionRefs.push(new AudioSessionRef(audioSession, caller));
+    ALOGV(" added new entry for %d", audioSession);
 }
 
 void AudioFlinger::releaseAudioSessionId(int audioSession)
diff --git a/services/audioflinger/AudioFlinger.h b/services/audioflinger/AudioFlinger.h
index 76beeafe6579..ab5ec3468118 100644
--- a/services/audioflinger/AudioFlinger.h
+++ b/services/audioflinger/AudioFlinger.h
@@ -233,9 +233,9 @@ private:
     private:
                             Client(const Client&);
                             Client& operator = (const Client&);
-        sp<AudioFlinger>    mAudioFlinger;
-        sp<MemoryDealer>    mMemoryDealer;
-        pid_t               mPid;
+        const sp<AudioFlinger> mAudioFlinger;
+        const sp<MemoryDealer> mMemoryDealer;
+        const pid_t         mPid;
     };
 
     // --- Notification Client ---
@@ -246,7 +246,7 @@ private:
                                                 pid_t pid);
         virtual             ~NotificationClient();
 
-                sp<IAudioFlingerClient>    client() { return mClient; }
+                sp<IAudioFlingerClient> audioFlingerClient() const { return mAudioFlingerClient; }
 
                 // IBinder::DeathRecipient
                 virtual     void        binderDied(const wp<IBinder>& who);
@@ -255,9 +255,9 @@ private:
                             NotificationClient(const NotificationClient&);
                             NotificationClient& operator = (const NotificationClient&);
 
-        sp<AudioFlinger>        mAudioFlinger;
-        pid_t                   mPid;
-        sp<IAudioFlingerClient> mClient;
+        const sp<AudioFlinger>  mAudioFlinger;
+        const pid_t             mPid;
+        const sp<IAudioFlingerClient> mAudioFlingerClient;
     };
 
     class TrackHandle;
@@ -367,8 +367,8 @@ private:
             bool step();
             void reset();
 
-            wp<ThreadBase>      mThread;
-            sp<Client>          mClient;
+            const wp<ThreadBase> mThread;
+            /*const*/ sp<Client> mClient;   // see explanation at ~TrackBase() why not const
             sp<IMemory>         mCblkMemory;
             audio_track_cblk_t* mCblk;
             void*               mBuffer;
@@ -377,9 +377,9 @@ private:
             // we don't really need a lock for these
             track_state         mState;
             int                 mClientTid;
-            audio_format_t      mFormat;
+            const audio_format_t mFormat;
             uint32_t            mFlags;
-            int                 mSessionId;
+            const int           mSessionId;
             uint8_t             mChannelCount;
             uint32_t            mChannelMask;
         };
@@ -532,7 +532,7 @@ private:
 
                     const type_t            mType;
                     Condition               mWaitWorkCV;
-                    sp<AudioFlinger>        mAudioFlinger;
+                    const sp<AudioFlinger>  mAudioFlinger;
                     uint32_t                mSampleRate;
                     size_t                  mFrameCount;
                     uint32_t                mChannelMask;
@@ -553,7 +553,7 @@ private:
                     char                    mName[kNameLength];
                     sp<IPowerManager>       mPowerManager;
                     sp<IBinder>             mWakeLockToken;
-                    sp<PMDeathRecipient>    mDeathRecipient;
+                    const sp<PMDeathRecipient> mDeathRecipient;
                     // list of suspended effects per session and per type. The first vector is
                     // keyed by session ID, the second by type UUID timeLow field
                     KeyedVector< int, KeyedVector< int, sp<SuspendedSessionDesc> > >  mSuspendedSessions;
@@ -671,7 +671,7 @@ private:
                     bool        write(int16_t* data, uint32_t frames);
                     bool        bufferQueueEmpty() { return (mBufferQueue.size() == 0) ? true : false; }
                     bool        isActive() { return mActive; }
-            wp<ThreadBase>&     thread()  { return mThread; }
+            const wp<ThreadBase>& thread() { return mThread; }
 
         private:
 
@@ -688,7 +688,7 @@ private:
             Vector < Buffer* >          mBufferQueue;
             AudioBufferProvider::Buffer mOutBuffer;
             bool                        mActive;
-            DuplicatingThread*          mSourceThread;
+            DuplicatingThread* const mSourceThread; // for waitTimeMs() in write()
         };  // end of OutputTrack
 
         PlaybackThread (const sp<AudioFlinger>& audioFlinger, AudioStreamOut* output, int id,
@@ -919,7 +919,7 @@ private:
         virtual status_t onTransact(
             uint32_t code, const Parcel& data, Parcel* reply, uint32_t flags);
     private:
-        sp<PlaybackThread::Track> mTrack;
+        const sp<PlaybackThread::Track> mTrack;
     };
 
     friend class Client;
@@ -1023,8 +1023,8 @@ private:
                 int16_t                             *mRsmpInBuffer;
                 size_t                              mRsmpInIndex;
                 size_t                              mInputBytes;
-                int                                 mReqChannelCount;
-                uint32_t                            mReqSampleRate;
+                const int                           mReqChannelCount;
+                const uint32_t                      mReqSampleRate;
                 ssize_t                             mBytesRead;
     };
 
@@ -1038,7 +1038,7 @@ private:
         virtual status_t onTransact(
             uint32_t code, const Parcel& data, Parcel* reply, uint32_t flags);
     private:
-        sp<RecordThread::RecordTrack> mRecordTrack;
+        const sp<RecordThread::RecordTrack> mRecordTrack;
     };
 
     //--- Audio Effect Management
@@ -1107,7 +1107,7 @@ private:
         int16_t     *outBuffer() { return mConfig.outputCfg.buffer.s16; }
         void        setChain(const wp<EffectChain>& chain) { mChain = chain; }
         void        setThread(const wp<ThreadBase>& thread) { mThread = thread; }
-        wp<ThreadBase>& thread() { return mThread; }
+        const wp<ThreadBase>& thread() { return mThread; }
 
         status_t addHandle(const sp<EffectHandle>& handle);
         void disconnect(const wp<EffectHandle>& handle, bool unpiniflast);
@@ -1379,8 +1379,11 @@ mutable Mutex               mLock;      // mutex for process, commands and handl
     };
 
     struct AudioSessionRef {
-        int sessionid;
-        pid_t pid;
+        // FIXME rename parameter names when fields get "m" prefix
+        AudioSessionRef(int sessionid_, pid_t pid_) :
+            sessionid(sessionid_), pid(pid_), cnt(1) {}
+        const int sessionid;
+        const pid_t pid;
         int cnt;
     };
 
diff --git a/services/audioflinger/AudioMixer.cpp b/services/audioflinger/AudioMixer.cpp
index a01c6a84b22b..1f7d883068c4 100644
--- a/services/audioflinger/AudioMixer.cpp
+++ b/services/audioflinger/AudioMixer.cpp
@@ -48,9 +48,10 @@ AudioMixer::AudioMixer(size_t frameCount, uint32_t sampleRate)
     mState.enabledTracks= 0;
     mState.needsChanged = 0;
     mState.frameCount   = frameCount;
+    mState.hook         = process__nop;
     mState.outputTemp   = NULL;
     mState.resampleTemp = NULL;
-    mState.hook         = process__nop;
+    // mState.reserved
     track_t* t = mState.tracks;
     for (unsigned i=0 ; i < MAX_NUM_TRACKS ; i++) {
         t->needs = 0;
@@ -70,12 +71,13 @@ AudioMixer::AudioMixer(size_t frameCount, uint32_t sampleRate)
         t->enabled = 0;
         t->format = 16;
         t->channelMask = AUDIO_CHANNEL_OUT_STEREO;
-        t->buffer.raw = 0;
         t->bufferProvider = NULL;
+        t->buffer.raw = NULL;
+        // t->buffer.frameCount
         t->hook = NULL;
+        t->in = NULL;
         t->resampler = NULL;
         t->sampleRate = mSampleRate;
-        t->in = NULL;
         t->mainBuffer = NULL;
         t->auxBuffer = NULL;
         t++;