libaudiohal: Implement simple HIDL client

This client requires both HIDL client and server to be of the same
ABI version (e.g. 32-bit).

EffectHalHidl::process and EffectHalHidl::processReverse are stubs.

Some extra warnings are logged due to unimplemented functions
in the legacy HAL.

Bug: 30222631
Change-Id: Id074131dec6d6c4f1031695abcf3ea066e92a5af
Test: Play Music (play / EQ), YouTube, Loopback RTLT, Ok Google on N5X
diff --git a/media/libaudiohal/EffectsFactoryHalHidl.h b/media/libaudiohal/EffectsFactoryHalHidl.h
new file mode 100644
index 0000000..f16db17
--- /dev/null
+++ b/media/libaudiohal/EffectsFactoryHalHidl.h
@@ -0,0 +1,67 @@
+/*
+ * Copyright (C) 2016 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.
+ */
+
+#ifndef ANDROID_HARDWARE_EFFECTS_FACTORY_HAL_HIDL_H
+#define ANDROID_HARDWARE_EFFECTS_FACTORY_HAL_HIDL_H
+
+#include <android/hardware/audio/effect/2.0/IEffectsFactory.h>
+#include <android/hardware/audio/effect/2.0/types.h>
+#include <media/audiohal/EffectsFactoryHalInterface.h>
+
+namespace android {
+
+using ::android::hardware::audio::effect::V2_0::EffectDescriptor;
+using ::android::hardware::audio::effect::V2_0::IEffectsFactory;
+using ::android::hardware::hidl_vec;
+
+class EffectsFactoryHalHidl : public EffectsFactoryHalInterface
+{
+  public:
+    // Returns the number of different effects in all loaded libraries.
+    virtual status_t queryNumberEffects(uint32_t *pNumEffects);
+
+    // Returns a descriptor of the next available effect.
+    virtual status_t getDescriptor(uint32_t index,
+            effect_descriptor_t *pDescriptor);
+
+    virtual status_t getDescriptor(const effect_uuid_t *pEffectUuid,
+            effect_descriptor_t *pDescriptor);
+
+    // Creates an effect engine of the specified type.
+    // To release the effect engine, it is necessary to release references
+    // to the returned effect object.
+    virtual status_t createEffect(const effect_uuid_t *pEffectUuid,
+            int32_t sessionId, int32_t ioId,
+            sp<EffectHalInterface> *effect);
+
+    virtual status_t dumpEffects(int fd);
+
+  private:
+    friend class EffectsFactoryHalInterface;
+
+    sp<IEffectsFactory> mEffectsFactory;
+    hidl_vec<EffectDescriptor> mLastDescriptors;
+
+    // Can not be constructed directly by clients.
+    EffectsFactoryHalHidl();
+    virtual ~EffectsFactoryHalHidl();
+
+    status_t queryAllDescriptors();
+};
+
+} // namespace android
+
+#endif // ANDROID_HARDWARE_EFFECTS_FACTORY_HAL_HIDL_H