Android 8 声音调整过程

记录Android 8声音调整过程。

frameworks\base\services\core\java\com\android\server\policy\PhoneWindowManager.java
    private void dispatchDirectAudioEvent(KeyEvent event) {
        if (event.getAction() != KeyEvent.ACTION_DOWN) {
            return;
        }
        int keyCode = event.getKeyCode();
        int flags = AudioManager.FLAG_SHOW_UI | AudioManager.FLAG_PLAY_SOUND
                | AudioManager.FLAG_FROM_KEY;
        String pkgName = mContext.getOpPackageName();
        switch (keyCode) {
            case KeyEvent.KEYCODE_VOLUME_UP:
                try {
                    getAudioService().adjustSuggestedStreamVolume(AudioManager.ADJUST_RAISE,
                            AudioManager.USE_DEFAULT_STREAM_TYPE, flags, pkgName, TAG);
                } catch (Exception e) {
                    Log.e(TAG, "Error dispatching volume up in dispatchTvAudioEvent.", e);
                }
                break;
            case KeyEvent.KEYCODE_VOLUME_DOWN:
                try {
                    getAudioService().adjustSuggestedStreamVolume(AudioManager.ADJUST_LOWER,
                            AudioManager.USE_DEFAULT_STREAM_TYPE, flags, pkgName, TAG);
                } catch (Exception e) {
                    Log.e(TAG, "Error dispatching volume down in dispatchTvAudioEvent.", e);
                }
                break;
            case KeyEvent.KEYCODE_VOLUME_MUTE:
                try {
                    if (event.getRepeatCount() == 0) {
                        getAudioService().adjustSuggestedStreamVolume(
                                AudioManager.ADJUST_TOGGLE_MUTE,
                                AudioManager.USE_DEFAULT_STREAM_TYPE, flags, pkgName, TAG);
                    }
                } catch (Exception e) {
                    Log.e(TAG, "Error dispatching mute in dispatchTvAudioEvent.", e);
                }
                break;
        }
    }

frameworks\base\services\core\java\com\android\server\audio\AudioService.java
	   /** @see AudioManager#adjustVolume(int, int) */
    public void adjustSuggestedStreamVolume(int direction, int suggestedStreamType, int flags,
            String callingPackage, String caller) {
        adjustSuggestedStreamVolume(direction, suggestedStreamType, flags, callingPackage,
                caller, Binder.getCallingUid());
    }

    private void adjustSuggestedStreamVolume(int direction, int suggestedStreamType, int flags,
            String callingPackage, String caller, int uid) {
        mVolumeLogger.log(new VolumeEvent(VolumeEvent.VOL_ADJUST_SUGG_VOL, suggestedStreamType,
                direction/*val1*/, flags/*val2*/, new StringBuilder(callingPackage)
                        .append("/").append(caller).append(" uid:").append(uid).toString()));
        final int streamType;
        synchronized (mForceControlStreamLock) {
            if (DEBUG_VOL) Log.d(TAG, "adjustSuggestedStreamVolume() stream=" + suggestedStreamType
                    + ", flags=" + flags + ", caller=" + caller
                    + ", volControlStream=" + mVolumeControlStream
                    + ", userSelect=" + mUserSelectedVolumeControlStream);
            if (mUserSelectedVolumeControlStream) { // implies mVolumeControlStream != -1
                streamType = mVolumeControlStream;
            } else {
                // 获取当前StreamType类型，传入的是AudioManager.USE_DEFAULT_STREAM_TYPE
                // AudioSystem.STREAM_MUSIC
                final int maybeActiveStreamType = getActiveStreamType(suggestedStreamType);
                final boolean activeForReal;
                if (maybeActiveStreamType == AudioSystem.STREAM_MUSIC) {
                    // 判断AudioFlinger当前是否是用AudioSystem.STREAM_MUSIC
                    activeForReal = isAfMusicActiveRecently(0);
                } else {
                    activeForReal = AudioSystem.isStreamActive(maybeActiveStreamType, 0);
                }
                // 获取声音类型, 就是前面getActiveStreamType得到的AudioSystem.STREAM_MUSIC
                if (activeForReal || mVolumeControlStream == -1) {
                    streamType = maybeActiveStreamType;
                } else {
                    streamType = mVolumeControlStream;
                }
            }
        }
        // 判断是否是MUTE操作
        final boolean isMute = isMuteAdjust(direction);
        // 判断类型是否合法
        ensureValidStreamType(streamType);
        final int resolvedStream = mStreamVolumeAlias[streamType];
        // RING类型声音处理
        // Play sounds on STREAM_RING only.
        if ((flags & AudioManager.FLAG_PLAY_SOUND) != 0 &&
                resolvedStream != AudioSystem.STREAM_RING) {
            flags &= ~AudioManager.FLAG_PLAY_SOUND;
        }
        // 通知或者电话，显示UI,但是不进行MUTE操作
        // For notifications/ring, show the ui before making any adjustments
        // Don't suppress mute/unmute requests
        if (mVolumeController.suppressAdjustment(resolvedStream, flags, isMute)) {
            direction = 0;
            // 将相应的位清零
            flags &= ~AudioManager.FLAG_PLAY_SOUND;
            flags &= ~AudioManager.FLAG_VIBRATE;
            if (DEBUG_VOL) Log.d(TAG, "Volume controller suppressed adjustment");
        }

        adjustStreamVolume(streamType, direction, flags, callingPackage, caller, uid);
    }

    /** @see AudioManager#adjustStreamVolume(int, int, int) */
    public void adjustStreamVolume(int streamType, int direction, int flags,
            String callingPackage) {
        if ((streamType == AudioManager.STREAM_ACCESSIBILITY) && !canChangeAccessibilityVolume()) {
            Log.w(TAG, "Trying to call adjustStreamVolume() for a11y without"
                    + "CHANGE_ACCESSIBILITY_VOLUME / callingPackage=" + callingPackage);
            return;
        }
        mVolumeLogger.log(new VolumeEvent(VolumeEvent.VOL_ADJUST_STREAM_VOL, streamType,
                direction/*val1*/, flags/*val2*/, callingPackage));
        adjustStreamVolume(streamType, direction, flags, callingPackage, callingPackage,
                Binder.getCallingUid());
    }

    private void adjustStreamVolume(int streamType, int direction, int flags,
            String callingPackage, String caller, int uid) {
        if (mUseFixedVolume) {
            return;
        }
        if (DEBUG_VOL) Log.d(TAG, "adjustStreamVolume() stream=" + streamType + ", dir=" + direction
                + ", flags=" + flags + ", caller=" + caller);
        // 判断参数是否合法
        ensureValidDirection(direction);
        ensureValidStreamType(streamType);

        boolean isMuteAdjust = isMuteAdjust(direction);
        // 判断声音是否受MUTE影响
        if (isMuteAdjust && !isStreamAffectedByMute(streamType)) {
            return;
        }

        // use stream type alias here so that streams with same alias have the same behavior,
        // including with regard to silent mode control (e.g the use of STREAM_RING below and in
        // checkForRingerModeChange() in place of STREAM_RING or STREAM_NOTIFICATION)
        // 获取声音类型的别名
        int streamTypeAlias = mStreamVolumeAlias[streamType];

        VolumeStreamState streamState = mStreamStates[streamTypeAlias];
        // 获取声音对应的device
        final int device = getDeviceForStream(streamTypeAlias);

        int aliasIndex = streamState.getIndex(device);
        boolean adjustVolume = true;
        int step;
        // 跳过蓝牙请求，如果对应的设备不是蓝牙
        // skip a2dp absolute volume control request when the device
        // is not an a2dp device
        if ((device & AudioSystem.DEVICE_OUT_ALL_A2DP) == 0 &&
            (flags & AudioManager.FLAG_BLUETOOTH_ABS_VOLUME) != 0) {
            return;
        }
        // 获取UID
        // If we are being called by the system (e.g. hardware keys) check for current user
        // so we handle user restrictions correctly.
        if (uid == android.os.Process.SYSTEM_UID) {
            uid = UserHandle.getUid(getCurrentUserId(), UserHandle.getAppId(uid));
        }
        if (mAppOps.noteOp(STREAM_VOLUME_OPS[streamTypeAlias], uid, callingPackage)
                != AppOpsManager.MODE_ALLOWED) {
            return;
        }

        // reset any pending volume command
        synchronized (mSafeMediaVolumeState) {
            mPendingVolumeCommand = null;
        }

        flags &= ~AudioManager.FLAG_FIXED_VOLUME;
        if ((streamTypeAlias == AudioSystem.STREAM_MUSIC) &&
               ((device & mFixedVolumeDevices) != 0)) {
            flags |= AudioManager.FLAG_FIXED_VOLUME;

            // Always toggle between max safe volume and 0 for fixed volume devices where safe
            // volume is enforced, and max and 0 for the others.
            // This is simulated by stepping by the full allowed volume range
            if (mSafeMediaVolumeState == SAFE_MEDIA_VOLUME_ACTIVE &&
                    (device & mSafeMediaVolumeDevices) != 0) {
                step = safeMediaVolumeIndex(device);
            } else {
                step = streamState.getMaxIndex();
            }
            if (aliasIndex != 0) {
                aliasIndex = step;
            }
        } else {
            // 更改UI上的显示，增加/减少一格
            // convert one UI step (+/-1) into a number of internal units on the stream alias
            step = rescaleIndex(10, streamType, streamTypeAlias);
        }
        // 对与RINGER_MODES有关的声音组处理
        // If either the client forces allowing ringer modes for this adjustment,
        // or the stream type is one that is affected by ringer modes
        if (((flags & AudioManager.FLAG_ALLOW_RINGER_MODES) != 0) ||
                (streamTypeAlias == getUiSoundsStreamType())) {
            int ringerMode = getRingerModeInternal();
            // do not vibrate if already in vibrate mode
            if (ringerMode == AudioManager.RINGER_MODE_VIBRATE) {
                flags &= ~AudioManager.FLAG_VIBRATE;
            }
            // Check if the ringer mode handles this adjustment. If it does we don't
            // need to adjust the volume further.
            final int result = checkForRingerModeChange(aliasIndex, direction, step,
                    streamState.mIsMuted, callingPackage, flags);
            adjustVolume = (result & FLAG_ADJUST_VOLUME) != 0;
            // If suppressing a volume adjustment in silent mode, display the UI hint
            if ((result & AudioManager.FLAG_SHOW_SILENT_HINT) != 0) {
                flags |= AudioManager.FLAG_SHOW_SILENT_HINT;
            }
            // If suppressing a volume down adjustment in vibrate mode, display the UI hint
            if ((result & AudioManager.FLAG_SHOW_VIBRATE_HINT) != 0) {
                flags |= AudioManager.FLAG_SHOW_VIBRATE_HINT;
            }
        }
        // If the ringermode is suppressing media, prevent changes
        if (!volumeAdjustmentAllowedByDnd(streamTypeAlias, flags)) {
            adjustVolume = false;
        }
        int oldIndex = mStreamStates[streamType].getIndex(device);

        if (adjustVolume && (direction != AudioManager.ADJUST_SAME)) {
            mAudioHandler.removeMessages(MSG_UNMUTE_STREAM);
            // 判断是否要更新蓝牙的音量
            // Check if volume update should be send to AVRCP
            if (streamTypeAlias == AudioSystem.STREAM_MUSIC &&
                (device & AudioSystem.DEVICE_OUT_ALL_A2DP) != 0 &&
                (flags & AudioManager.FLAG_BLUETOOTH_ABS_VOLUME) == 0) {
                synchronized (mA2dpAvrcpLock) {
                    if (mA2dp != null && mAvrcpAbsVolSupported) {
                        mA2dp.adjustAvrcpAbsoluteVolume(direction);
                    }
                }
            }

            if (isMuteAdjust) {
                boolean state;
                if (direction == AudioManager.ADJUST_TOGGLE_MUTE) {
                    state = !streamState.mIsMuted;
                } else {
                    state = direction == AudioManager.ADJUST_MUTE;
                }
                if (streamTypeAlias == AudioSystem.STREAM_MUSIC) {
                    setSystemAudioMute(state);
                }
                for (int stream = 0; stream < mStreamStates.length; stream++) {
                    if (streamTypeAlias == mStreamVolumeAlias[stream]) {
                        if (!(readCameraSoundForced()
                                    && (mStreamStates[stream].getStreamType()
                                        == AudioSystem.STREAM_SYSTEM_ENFORCED))) {
                            mStreamStates[stream].mute(state);
                        }
                    }
                }
            } else if ((direction == AudioManager.ADJUST_RAISE) &&
                    !checkSafeMediaVolume(streamTypeAlias, aliasIndex + step, device)) {
                Log.e(TAG, "adjustStreamVolume() safe volume index = " + oldIndex);
                mVolumeController.postDisplaySafeVolumeWarning(flags);
            } else if (streamState.adjustIndex(direction * step, device, caller)
                    || streamState.mIsMuted) {
                // Post message to set system volume (it in turn will post a
                // message to persist).
                if (streamState.mIsMuted) {
                    // 静音的情况下先unmute设备
                    // Unmute the stream if it was previously muted
                    if (direction == AudioManager.ADJUST_RAISE) {
                        // unmute immediately for volume up
                        streamState.mute(false);
                    } else if (direction == AudioManager.ADJUST_LOWER) {
                        if (mIsSingleVolume) {
                            sendMsg(mAudioHandler, MSG_UNMUTE_STREAM, SENDMSG_QUEUE,
                                    streamTypeAlias, flags, null, UNMUTE_STREAM_DELAY);
                        }
                    }
                }
				// 调整声音大小，并保存声音的数据
                sendMsg(mAudioHandler,
                        MSG_SET_DEVICE_VOLUME,
                        SENDMSG_QUEUE,
                        device,
                        0,
                        streamState,
                        0);
            }

            // Check if volume update should be sent to Hdmi system audio.
            int newIndex = mStreamStates[streamType].getIndex(device);
            if (streamTypeAlias == AudioSystem.STREAM_MUSIC) {
                setSystemAudioVolume(oldIndex, newIndex, getStreamMaxVolume(streamType), flags);
            }
            if (mHdmiManager != null) {
                synchronized (mHdmiManager) {
                    // mHdmiCecSink true => mHdmiPlaybackClient != null
                    if (mHdmiCecSink &&
                            streamTypeAlias == AudioSystem.STREAM_MUSIC &&
                            oldIndex != newIndex) {
                        synchronized (mHdmiPlaybackClient) {
                            int keyCode = (direction == -1) ? KeyEvent.KEYCODE_VOLUME_DOWN :
                                    KeyEvent.KEYCODE_VOLUME_UP;
                            final long ident = Binder.clearCallingIdentity();
                            try {
                                mHdmiPlaybackClient.sendKeyEvent(keyCode, true);
                                mHdmiPlaybackClient.sendKeyEvent(keyCode, false);
                            } finally {
                                Binder.restoreCallingIdentity(ident);
                            }
                        }
                    }
                }
            }
        }
        int index = mStreamStates[streamType].getIndex(device);
        sendVolumeUpdate(streamType, oldIndex, index, flags);		//更新UI显示
    }

frameworks\base\services\core\java\com\android\server\audio\AudioService.java
	 private class AudioHandler extends Handler {

	         @Override
        public void handleMessage(Message msg) {
            switch (msg.what) {

                case MSG_SET_DEVICE_VOLUME:
                    setDeviceVolume((VolumeStreamState) msg.obj, msg.arg1);
                    break;

                case MSG_SET_ALL_VOLUMES:
                    setAllVolumes((VolumeStreamState) msg.obj);
                    break;

                case MSG_PERSIST_VOLUME:
                    persistVolume((VolumeStreamState) msg.obj, msg.arg1);
                    break;

                case MSG_PERSIST_RINGER_MODE:
                    // note that the value persisted is the current ringer mode, not the
                    // value of ringer mode as of the time the request was made to persist
                    persistRingerMode(getRingerModeInternal());
                    break;

       private void setDeviceVolume(VolumeStreamState streamState, int device) {

            synchronized (VolumeStreamState.class) {
                // Apply volume
                streamState.applyDeviceVolume_syncVSS(device);				// 将声音的数据写到底层

                // Apply change to all streams using this one as alias
                int numStreamTypes = AudioSystem.getNumStreamTypes();
                for (int streamType = numStreamTypes - 1; streamType >= 0; streamType--) {
                    if (streamType != streamState.mStreamType &&
                            mStreamVolumeAlias[streamType] == streamState.mStreamType) {
                        // Make sure volume is also maxed out on A2DP device for aliased stream
                        // that may have a different device selected
                        int streamDevice = getDeviceForStream(streamType);
                        if ((device != streamDevice) && mAvrcpAbsVolSupported &&
                                ((device & AudioSystem.DEVICE_OUT_ALL_A2DP) != 0)) {
                            mStreamStates[streamType].applyDeviceVolume_syncVSS(device);
                        }
                        mStreamStates[streamType].applyDeviceVolume_syncVSS(streamDevice);
                    }
                }
            }
            // Post a persist volume msg
            sendMsg(mAudioHandler,
                    MSG_PERSIST_VOLUME,
                    SENDMSG_QUEUE,
                    device,
                    0,
                    streamState,
                    PERSIST_DELAY);

        }

		  private void persistVolume(VolumeStreamState streamState, int device) {
            if (mUseFixedVolume) {
                return;
            }
            if (mIsSingleVolume && (streamState.mStreamType != AudioSystem.STREAM_MUSIC)) {
                return;
            }
            if (streamState.hasValidSettingsName()) {
                // 将参数保存
                System.putIntForUser(mContentResolver,
                        streamState.getSettingNameForDevice(device),
                        (streamState.getIndex(device) + 5)/ 10,
                        UserHandle.USER_CURRENT);
            }
        }