Import of the watch repository from Pebble

src/fw/kernel/task_timer_manager.h

@@ -0,0 +1,57 @@
+/*
+ * 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 "task_timer.h"
+
+//! Internal state object. Each task that wants to execute timers should allocate their own
+//! instance of this object.
+typedef struct TaskTimerManager {
+  PebbleMutex *mutex;
+
+  //! List of timers that are currently running
+  ListNode *running_timers;
+  //! List of timers that are allocated but unscheduled
+  ListNode *idle_timers;
+
+  //! The next ID to assign to a new timer.
+  TaskTimerID next_id;
+
+  //! Externally provided semaphore that is given whenever the next timer to expire has changed.
+  SemaphoreHandle_t semaphore;
+
+  //! The callback we're currently executing, useful for debugging.
+  void *current_cb;
+} TaskTimerManager;
+
+
+//! Initialize a passed in manager object.
+//! @param[in] semaphore a sempahore the TaskTimerManager should give if the next expiring timer
+//!                      has changed. The task event loop should block on this same semphore to
+//!                      handle timer updates in a timely fashion.
+void task_timer_manager_init(TaskTimerManager *manager, SemaphoreHandle_t semaphore);
+
+//! Execute any timers that are currently expired.
+//! @return the number of ticks until the next timer expires. If there are no timers running,
+//!         returns portMAX_DELAY.
+TickType_t task_timer_manager_execute_expired_timers(TaskTimerManager *manager);
+
+//! Debugging interface to help understand why the task_timer exuction is stuck and what
+//! its stuck on.
+//! @return A pointer to the current callback that's running, NULL if no callback
+//!         is currently running.
+void* task_timer_manager_get_current_cb(const TaskTimerManager *manager);