Merge "MediaMetrics: Retain previous audio state a limited time." into rvc-dev

static constexpr const auto LOG_LEVEL = android::base::VERBOSE;

static constexpr int PREVIOUS_STATE_EXPIRE_SEC = 60 * 60; // 1 hour.

/*

 * For logging purposes, we list all of the MediaMetrics atom fields,

 * which can then be associated with consecutive arguments to the statsd write.

                // to end of full expression.

                mAnalyticsState->clear();  // TODO: filter the analytics state.

                // Perhaps report this.

                // Set up a timer to expire the previous audio state to save space.

                // Use the transaction log size as a cookie to see if it is the

                // same as before.  A benign race is possible where a state is cleared early.

                const size_t size = mPreviousAnalyticsState->transactionLog().size();

                mTimedAction.postIn(

                        std::chrono::seconds(PREVIOUS_STATE_EXPIRE_SEC), [this, size](){

                    if (mPreviousAnalyticsState->transactionLog().size() == size) {

                        ALOGD("expiring previous audio state after %d seconds.",

                                PREVIOUS_STATE_EXPIRE_SEC);

                        mPreviousAnalyticsState->clear();  // removes data from the state.

                    }

                });

            }));

    // Handle device use record statistics

    // AnalyticsState is individually locked, and we use SharedPtrWrap

    // to allow safe access even if the shared pointer changes underneath.

    // These wrap pointers always point to a valid state object.

    SharedPtrWrap<AnalyticsState> mAnalyticsState;

    SharedPtrWrap<AnalyticsState> mPreviousAnalyticsState;