*

ODrive-fw-v0.5.6/Firmware/fibre-cpp/include/fibre/event_loop.hpp

@@ -0,0 +1,74 @@
+#ifndef __FIBRE_EVENT_LOOP_HPP
+#define __FIBRE_EVENT_LOOP_HPP
+
+#include "callback.hpp"
+#include <stdint.h>
+
+namespace fibre {
+
+struct EventLoopTimer;
+
+/**
+ * @brief Base class for event loops.
+ * 
+ * Thread-safety: The public functions of this class except for post() must not
+ * be assumed to be thread-safe.
+ * Generally the functions of an event loop are only safe to be called from the
+ * event loop's thread itself.
+ */
+class EventLoop {
+public:
+    /**
+     * @brief Registers a callback for immediate execution on the event loop
+     * thread.
+     * 
+     * This function must be thread-safe.
+     */
+    virtual bool post(Callback<void> callback) = 0;
+
+    /**
+     * @brief Registers the given file descriptor on this event loop.
+     * 
+     * This function is only implemented on Unix-like systems.
+     * 
+     * @param fd: A waitable Unix file descriptor on which to listen for events.
+     * @param events: A bitfield that specifies the events to listen for.
+     *        For instance EPOLLIN or EPOLLOUT.
+     * @param callback: The callback to invoke every time the event triggers.
+     *        A bitfield is passed to the callback to indicate which events were
+     *        triggered. This callback must remain valid until
+     *        deregister_event() is called for the same file descriptor.
+     */
+    virtual bool register_event(int fd, uint32_t events, Callback<void, uint32_t> callback) = 0;
+
+    /**
+     * @brief Deregisters the given event.
+     * 
+     * Once this function returns, the associated callback will no longer be
+     * invoked and its resources can be freed.
+     */
+    virtual bool deregister_event(int fd) = 0;
+
+    /**
+     * @brief Registers a callback to be called at a later point in time.
+     * 
+     * This returns an opaque handler which can be used to cancel the timer.
+     * 
+     * @param delay: The delay from now in seconds.
+     *               TOOD: specify if OS sleep time is counted in.
+     */
+    virtual struct EventLoopTimer* call_later(float delay, Callback<void> callback) = 0;
+
+    /**
+     * @brief Cancels a timer which was previously started by call_later().
+     * 
+     * Must not be called after invokation of the callback has started.
+     * This also means that cancel_timer() must not be called from within the
+     * callback of the timer itself.
+     */
+    virtual bool cancel_timer(EventLoopTimer* timer) = 0;
+};
+
+}
+
+#endif // __FIBRE_EVENT_LOOP_HPP