/*
 * Copyright (C) 2017 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.
 */

package android.hardware.neuralnetworks@1.0;

import IExecutionCallback;

/**
 * IPreparedModel describes a model that has been prepared for execution and
 * is used to launch executions.
 */
interface IPreparedModel {
    /**
     * Launches an asynchronous execution on a prepared model.
     *
     * The execution is performed asynchronously with respect to the caller.
     * execute must verify the inputs to the function are correct. If there is
     * an error, execute must immediately invoke the callback with the
     * appropriate ErrorStatus value, then return with the same ErrorStatus. If
     * the inputs to the function are valid and there is no error, execute must
     * launch an asynchronous task to perform the execution in the background,
     * and immediately return with ErrorStatus::NONE. If the asynchronous task
     * fails to launch, execute must immediately invoke the callback with
     * ErrorStatus::GENERAL_FAILURE, then return with
     * ErrorStatus::GENERAL_FAILURE.
     *
     * When the asynchronous task has finished its execution, it must
     * immediately invoke the callback object provided as an input to the
     * execute function. This callback must be provided with the ErrorStatus of
     * the execution.
     *
     * If the launch is successful, the caller must not change the content of
     * any data object referenced by 'request' (described by the
     * {@link DataLocation} of a {@link RequestArgument}) until the
     * asynchronous task has invoked the callback object. The asynchronous task
     * must not change the content of any of the data objects corresponding to
     * 'request' inputs.
     *
     * If the prepared model was prepared from a model wherein all tensor
     * operands have fully specified dimensions, and the inputs to the function
     * are valid, then:
     * - the execution should launch successfully (ErrorStatus::NONE): There
     *   must be no failure unless the device itself is in a bad state.
     * - if at execution time every operation's input operands have legal
     *   values, the execution should complete successfully (ErrorStatus::NONE):
     *   There must be no failure unless the device itself is in a bad state.
     *
     * Multiple threads can call the execute function on the same IPreparedModel
     * object concurrently with different requests.
     *
     * @param request The input and output information on which the prepared
     *                model is to be executed.
     * @param callback A callback object used to return the error status of
     *                 the execution. The callback object's notify function must
     *                 be called exactly once, even if the execution was
     *                 unsuccessful.
     * @return status Error status of the call, must be:
     *                - NONE if task is successfully launched
     *                - DEVICE_UNAVAILABLE if driver is offline or busy
     *                - GENERAL_FAILURE if there is an unspecified error
     *                - OUTPUT_INSUFFICIENT_SIZE if provided output buffer is
     *                  not large enough to store the resultant values
     *                - INVALID_ARGUMENT if one of the input arguments is
     *                  invalid
     */
    execute(Request request, IExecutionCallback callback)
        generates (ErrorStatus status);
};