Add libaudiousecasevalidation library

This library will verify the audio attributes usage for a track
that is connected to the specified stream.

It will only update the audio attributes usage for AUDIO_USAGE_MEDIA or
AUDIO_USAGE_UNKNOWN, to AUDIO_USAGE_GAME if output flags AUDIO_OUTPUT_FLAG_FAST
or AUDIO_OUTPUT_FLAG_MMAP_NOIRQ have been set for specified stream.

Bug: 257922898
Test: atest libaudiousecasevalidation-test

Change-Id: Ic2d89fa05467538abbc97d707478df1d70901fdb
diff --git a/media/libaudiousecasevalidation/UsecaseValidator.cpp b/media/libaudiousecasevalidation/UsecaseValidator.cpp
new file mode 100644
index 0000000..3a8a9c1
--- /dev/null
+++ b/media/libaudiousecasevalidation/UsecaseValidator.cpp
@@ -0,0 +1,128 @@
+#define LOG_TAG "UsecaseValidator"
+// #define LOG_NDEBUG 0
+
+#include <inttypes.h>
+
+#include <utils/Log.h>
+
+#include "media/UsecaseValidator.h"
+#include "media/UsecaseLookup.h"
+
+namespace android {
+namespace media {
+namespace {
+
+class UsecaseValidatorImpl : public UsecaseValidator {
+ public:
+    UsecaseValidatorImpl() {}
+
+    /**
+     * Register a new mixer/stream.
+     * Called when the stream is opened at the HAL and communicates
+     * immutable stream attributes like flags, sampling rate, format.
+     */
+    status_t registerStream(audio_io_handle_t streamId,
+                            const audio_config_base_t& audioConfig __attribute__((unused)),
+                            const audio_output_flags_t outputFlags) override {
+        ALOGV("%s output: %d flags: %#x", __func__, streamId, outputFlags);
+
+        // Check if FAST or MMAP output flag has been set.
+        bool outputFlagGame = outputFlags & (AUDIO_OUTPUT_FLAG_FAST | AUDIO_OUTPUT_FLAG_MMAP_NOIRQ);
+        m_lookup.addStream(streamId, outputFlagGame);
+        return OK;
+    };
+
+    /**
+     * Unregister a stream/mixer.
+     * Called when the stream is closed.
+     */
+    status_t unregisterStream(audio_io_handle_t streamId) override {
+        ALOGV("%s output: %d", __func__, streamId);
+
+        m_lookup.removeStream(streamId);
+        return OK;
+    };
+
+    /**
+     * Indicates that some playback activity started on the stream.
+     * Called each time an audio track starts or resumes.
+     */
+    error::Result<audio_attributes_t> startClient(audio_io_handle_t streamId,
+            audio_port_handle_t portId, const content::AttributionSourceState& attributionSource,
+            const audio_attributes_t& attributes,
+            const AttributesChangedCallback *callback __attribute__((unused))) override {
+        ALOGV("%s output: %d portId: %d usage: %d pid: %d package: %s",
+                __func__, streamId, portId, attributes.usage, attributionSource.pid,
+                attributionSource.packageName.value_or("").c_str());
+
+        m_lookup.addTrack(streamId, portId);
+
+        return verifyAudioAttributes(streamId, attributionSource, attributes);
+    };
+
+    /**
+     * Indicates that some playback activity stopped on the stream.
+     * Called each time an audio track stops or pauses.
+     */
+    status_t stopClient(audio_io_handle_t streamId, audio_port_handle_t portId) override {
+        ALOGV("%s output: %d portId: %d", __func__, streamId, portId);
+
+        m_lookup.removeTrack(streamId, portId);
+        return OK;
+    };
+
+    /**
+     * Called to verify and update audio attributes for a track that is connected
+     * to the specified stream.
+     */
+    error::Result<audio_attributes_t> verifyAudioAttributes(audio_io_handle_t streamId,
+            const content::AttributionSourceState& attributionSource,
+            const audio_attributes_t& attributes) override {
+        ALOGV("%s output: %d usage: %d pid: %d package: %s",
+                __func__, streamId, attributes.usage, attributionSource.pid,
+                attributionSource.packageName.value_or("").c_str());
+
+        audio_attributes_t attrRet = attributes;
+
+        // Check if attribute usage media or unknown has been set.
+        bool isUsageValid = this->isUsageValid(attributes);
+
+        if (isUsageValid && m_lookup.isGameStream(streamId)) {
+            ALOGI("%s update usage: %d to AUDIO_USAGE_GAME for output: %d pid: %d package: %s",
+                    __func__, attributes.usage, streamId, attributionSource.pid,
+                    attributionSource.packageName.value_or("").c_str());
+            // Set attribute usage Game.
+            attrRet.usage = AUDIO_USAGE_GAME;
+        }
+
+        return {attrRet};
+    };
+
+ protected:
+    /**
+     * Check if attribute usage valid.
+     */
+    bool isUsageValid(const audio_attributes_t& attr) {
+        ALOGV("isUsageValid attr.usage: %d", attr.usage);
+        switch (attr.usage) {
+            case AUDIO_USAGE_MEDIA:
+            case AUDIO_USAGE_UNKNOWN:
+                return true;
+            default:
+                break;
+        }
+        return false;
+    }
+
+ protected:
+    UsecaseLookup m_lookup;
+};
+
+}  // namespace
+
+std::unique_ptr<UsecaseValidator> createUsecaseValidator() {
+    return std::make_unique<UsecaseValidatorImpl>();
+}
+
+}  // namespace media
+}  // namespace android