Import of the watch repository from Pebble

src/fw/applib/app_worker.h

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+/*
+ * Copyright 2024 Google LLC
+ *
+ * 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.
+ */
+
+#pragma once
+
+#include <stdbool.h>
+#include "util/uuid.h"
+
+//! @addtogroup Foundation
+//! @{
+//!   @addtogroup AppWorker
+//!   \brief Runs in the background, and can communicate with the foreground app.
+//!     @{
+
+
+//! Possible error codes from app_worker_launch, app_worker_kill
+typedef enum {
+  //! Success
+  APP_WORKER_RESULT_SUCCESS= 0,
+  //! No worker found for the current app
+  APP_WORKER_RESULT_NO_WORKER = 1,
+  //! A worker for a different app is already running
+  APP_WORKER_RESULT_DIFFERENT_APP = 2,
+  //! The worker is not running
+  APP_WORKER_RESULT_NOT_RUNNING = 3,
+  //! The worker is already running
+  APP_WORKER_RESULT_ALREADY_RUNNING = 4,
+  //! The user will be asked for confirmation
+  APP_WORKER_RESULT_ASKING_CONFIRMATION = 5,
+} AppWorkerResult;
+
+
+//! Generic structure of a worker message that can be sent between an app and its worker
+typedef struct {
+  uint16_t data0;
+  uint16_t data1;
+  uint16_t data2;
+} AppWorkerMessage;
+
+
+//! Determine if the worker for the current app is running
+//! @return true if running
+bool app_worker_is_running(void);
+
+//! Launch the worker for the current app. Note that this is an asynchronous operation, a result code
+//! of APP_WORKER_RESULT_SUCCESS merely means that the request was successfully queued up.
+//! @return result code
+AppWorkerResult app_worker_launch(void);
+
+//! Kill the worker for the current app. Note that this is an asynchronous operation, a result code
+//! of APP_WORKER_RESULT_SUCCESS merely means that the request was successfully queued up.
+//! @return result code
+AppWorkerResult app_worker_kill(void);
+
+
+//! Callback type for worker messages. Messages can be sent from worker to app or vice versa.
+//! @param type An application defined message type
+//! @param data pointer to message data. The receiver must know the structure of the data provided by the sender.
+typedef void (*AppWorkerMessageHandler)(uint16_t type, AppWorkerMessage *data);
+
+//! Subscribe to worker messages. Once subscribed, the handler gets called on every message emitted by the other task
+//! (either worker or app).
+//! @param handler A callback to be executed when the event is received
+//! @return true on success
+bool app_worker_message_subscribe(AppWorkerMessageHandler handler);
+
+//! Unsubscribe from worker messages. Once unsubscribed, the previously registered handler will no longer be called.
+//! @return true on success
+bool app_worker_message_unsubscribe(void);
+
+//! Send a message to the other task (either worker or app).
+//! @param type An application defined message type
+//! @param data the message data structure
+void app_worker_send_message(uint8_t type, AppWorkerMessage *data);
+
+
+//!   @} // end addtogroup AppWorker
+//! @} // end addtogroup Foundation
+
+//! @internal
+//! Register the app message service with the event service system
+void app_worker_message_init(void);
+
+