CSD: extract SoundDoseManager for MEL handling

The SoundDoseManager owns the aggregator which computes the sound dose.
This is a central place for passing the sound dose properties up to the
higher layers.

Test: UT and dumpsys media.audio_flinger
Bug: 255943034

Change-Id: I2d8139b9115bdd793d4ed418f2da6bc8782d32b3
diff --git a/services/audioflinger/sounddose/SoundDoseManager.h b/services/audioflinger/sounddose/SoundDoseManager.h
new file mode 100644
index 0000000..fae5ba7
--- /dev/null
+++ b/services/audioflinger/sounddose/SoundDoseManager.h
@@ -0,0 +1,80 @@
+/*
+**
+** Copyright 2022, The Android Open Source Project
+**
+** Licensed under the Apache License, Version 2.0 (the "License");
+** you may not use this file except in compliance with the License.
+** You may obtain a copy of the License at
+**
+**     http://www.apache.org/licenses/LICENSE-2.0
+**
+** Unless required by applicable law or agreed to in writing, software
+** distributed under the License is distributed on an "AS IS" BASIS,
+** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+** See the License for the specific language governing permissions and
+** limitations under the License.
+*/
+
+#pragma once
+
+#include <audio_utils/MelProcessor.h>
+#include <audio_utils/MelAggregator.h>
+#include <mutex>
+#include <unordered_map>
+
+namespace android {
+
+/** CSD is computed with a rolling window of 7 days. */
+constexpr int64_t kCsdWindowSeconds = 604800;  // 60 * 60 * 24 * 7
+
+class SoundDoseManager {
+public:
+    SoundDoseManager() : mMelAggregator(kCsdWindowSeconds) {};
+
+    /**
+     * \brief Creates or gets the callback assigned to the streamHandle
+     *
+     * \param deviceId          id for the devices where the stream is active.
+     * \param streanHandle      handle to the stream
+     */
+    sp<audio_utils::MelProcessor::MelCallback> getOrCreateCallbackForDevice(
+        audio_port_handle_t deviceId,
+        audio_io_handle_t streamHandle);
+
+    /**
+     * \brief Removes stream callback when MEL computation is not needed anymore
+     *
+     * \param streanHandle      handle to the stream
+     */
+    void removeStreamCallback(audio_io_handle_t streamHandle);
+
+    std::string dump() const;
+
+    // used for testing
+    size_t getCachedMelRecordsSize() const;
+private:
+    /**
+     * An implementation of the MelProcessor::MelCallback that is assigned to a
+     * specific device.
+     */
+    class Callback : public audio_utils::MelProcessor::MelCallback {
+    public:
+        Callback(SoundDoseManager& soundDoseManager, audio_port_handle_t deviceHandle)
+            : mSoundDoseManager(soundDoseManager), mDeviceHandle(deviceHandle) {}
+
+        void onNewMelValues(const std::vector<float>& mels,
+                            size_t offset,
+                            size_t length) const override;
+
+        SoundDoseManager& mSoundDoseManager;
+        audio_port_handle_t mDeviceHandle;
+    };
+
+    // no need for lock since MelAggregator is thread-safe
+    audio_utils::MelAggregator mMelAggregator;
+
+    std::mutex mLock;
+    std::unordered_map<audio_io_handle_t, sp<Callback>> mActiveCallbacks GUARDED_BY(mLock);
+};
+
+}  // namespace android