APM: support querying of audio playback routing

  Add support for querying the audio devices used for playback
routing for the given audio attributes.
  Take into account registered dynamic policies but disregard
secondary output descriptors as they are used for playback
capture.

Bug: 144440677
Test: atest AudioServiceHostTest
Change-Id: I102c57b432b044dc6b0ead49e0a30d8e9094411d
diff --git a/media/libaudioclient/AudioSystem.cpp b/media/libaudioclient/AudioSystem.cpp
index 941cf54..0742091 100644
--- a/media/libaudioclient/AudioSystem.cpp
+++ b/media/libaudioclient/AudioSystem.cpp
@@ -1017,6 +1017,16 @@
     return aps->getDevicesForStream(stream);
 }
 
+status_t AudioSystem::getDevicesForAttributes(const AudioAttributes &aa,
+                                              AudioDeviceTypeAddrVector *devices) {
+    if (devices == nullptr) {
+        return BAD_VALUE;
+    }
+    const sp<IAudioPolicyService>& aps = AudioSystem::get_audio_policy_service();
+    if (aps == 0) return PERMISSION_DENIED;
+    return aps->getDevicesForAttributes(aa, devices);
+}
+
 audio_io_handle_t AudioSystem::getOutputForEffect(const effect_descriptor_t *desc)
 {
     const sp<IAudioPolicyService>& aps = AudioSystem::get_audio_policy_service();
diff --git a/media/libaudioclient/IAudioPolicyService.cpp b/media/libaudioclient/IAudioPolicyService.cpp
index b9e6e33..87802a1 100644
--- a/media/libaudioclient/IAudioPolicyService.cpp
+++ b/media/libaudioclient/IAudioPolicyService.cpp
@@ -109,6 +109,7 @@
     SET_PREFERRED_DEVICE_FOR_PRODUCT_STRATEGY,
     REMOVE_PREFERRED_DEVICE_FOR_PRODUCT_STRATEGY,
     GET_PREFERRED_DEVICE_FOR_PRODUCT_STRATEGY,
+    GET_DEVICES_FOR_ATTRIBUTES,
 };
 
 #define MAX_ITEMS_PER_LIST 1024
@@ -1348,6 +1349,41 @@
         }
         return static_cast<status_t>(reply.readInt32());
     }
+
+    virtual status_t getDevicesForAttributes(const AudioAttributes &aa,
+            AudioDeviceTypeAddrVector *devices) const
+    {
+        if (devices == nullptr) {
+            return BAD_VALUE;
+        }
+        Parcel data, reply;
+        data.writeInterfaceToken(IAudioPolicyService::getInterfaceDescriptor());
+        status_t status = aa.writeToParcel(&data);
+        if (status != NO_ERROR) {
+            return status;
+        }
+        status = remote()->transact(GET_DEVICES_FOR_ATTRIBUTES, data, &reply);
+        if (status != NO_ERROR) {
+            // transaction failed, return error
+            return status;
+        }
+        status = static_cast<status_t>(reply.readInt32());
+        if (status != NO_ERROR) {
+            // APM method call failed, return error
+            return status;
+        }
+
+        const size_t numberOfDevices = (size_t)reply.readInt32();
+        for (size_t i = 0; i < numberOfDevices; i++) {
+            AudioDeviceTypeAddr device;
+            if (device.readFromParcel((Parcel*)&reply) == NO_ERROR) {
+                devices->push_back(device);
+            } else {
+                return FAILED_TRANSACTION;
+            }
+        }
+        return NO_ERROR;
+    }
 };
 
 IMPLEMENT_META_INTERFACE(AudioPolicyService, "android.media.IAudioPolicyService");
@@ -1414,7 +1450,8 @@
         case IS_CALL_SCREEN_MODE_SUPPORTED:
         case SET_PREFERRED_DEVICE_FOR_PRODUCT_STRATEGY:
         case REMOVE_PREFERRED_DEVICE_FOR_PRODUCT_STRATEGY:
-        case GET_PREFERRED_DEVICE_FOR_PRODUCT_STRATEGY: {
+        case GET_PREFERRED_DEVICE_FOR_PRODUCT_STRATEGY:
+        case GET_DEVICES_FOR_ATTRIBUTES: {
             if (!isServiceUid(IPCThreadState::self()->getCallingUid())) {
                 ALOGW("%s: transaction %d received from PID %d unauthorized UID %d",
                       __func__, code, IPCThreadState::self()->getCallingPid(),
@@ -2473,6 +2510,37 @@
             return NO_ERROR;
         }
 
+        case GET_DEVICES_FOR_ATTRIBUTES: {
+            CHECK_INTERFACE(IAudioPolicyService, data, reply);
+            AudioAttributes attributes;
+            status_t status = attributes.readFromParcel(&data);
+            if (status != NO_ERROR) {
+                return status;
+            }
+            AudioDeviceTypeAddrVector devices;
+            status = getDevicesForAttributes(attributes.getAttributes(), &devices);
+            // reply data formatted as:
+            //  - (int32) method call result from APM
+            //  - (int32) number of devices (n) if method call returned NO_ERROR
+            //  - n AudioDeviceTypeAddr         if method call returned NO_ERROR
+            reply->writeInt32(status);
+            if (status != NO_ERROR) {
+                return NO_ERROR;
+            }
+            status = reply->writeInt32(devices.size());
+            if (status != NO_ERROR) {
+                return status;
+            }
+            for (const auto& device : devices) {
+                status = device.writeToParcel(reply);
+                if (status != NO_ERROR) {
+                    return status;
+                }
+            }
+
+            return NO_ERROR;
+        }
+
         default:
             return BBinder::onTransact(code, data, reply, flags);
     }
diff --git a/media/libaudioclient/include/media/AudioSystem.h b/media/libaudioclient/include/media/AudioSystem.h
index c4b528e..ae8b59c 100644
--- a/media/libaudioclient/include/media/AudioSystem.h
+++ b/media/libaudioclient/include/media/AudioSystem.h
@@ -279,6 +279,8 @@
 
     static uint32_t getStrategyForStream(audio_stream_type_t stream);
     static audio_devices_t getDevicesForStream(audio_stream_type_t stream);
+    static status_t getDevicesForAttributes(const AudioAttributes &aa,
+                                            AudioDeviceTypeAddrVector *devices);
 
     static audio_io_handle_t getOutputForEffect(const effect_descriptor_t *desc);
     static status_t registerEffect(const effect_descriptor_t *desc,
diff --git a/media/libaudioclient/include/media/IAudioPolicyService.h b/media/libaudioclient/include/media/IAudioPolicyService.h
index 6623061..742762d 100644
--- a/media/libaudioclient/include/media/IAudioPolicyService.h
+++ b/media/libaudioclient/include/media/IAudioPolicyService.h
@@ -108,6 +108,8 @@
 
     virtual uint32_t getStrategyForStream(audio_stream_type_t stream) = 0;
     virtual audio_devices_t getDevicesForStream(audio_stream_type_t stream) = 0;
+    virtual status_t getDevicesForAttributes(const AudioAttributes &aa,
+            AudioDeviceTypeAddrVector *devices) const = 0;
     virtual audio_io_handle_t getOutputForEffect(const effect_descriptor_t *desc) = 0;
     virtual status_t registerEffect(const effect_descriptor_t *desc,
                                     audio_io_handle_t io,