cam: event_loop: Add support for file descriptor events

Extend the EventLoop class to support watching file descriptors for
read and write events.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>
Reviewed-by: Paul Elder <paul.elder@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Reviewed-by: Umang Jain <umang.jain@ideasonboard.com>

1 files changed, 20 insertions, 0 deletions

diff --git a/src/cam/event_loop.h b/src/cam/event_loop.h
index ba3ba3a4..57bb6fb3 100644
--- a/src/cam/event_loop.h
+++ b/src/cam/event_loop.h
@@ -8,6 +8,7 @@
 #define __CAM_EVENT_LOOP_H__
 
 #include <functional>
+#include <memory>
 #include <list>
 #include <mutex>
 
@@ -18,6 +19,11 @@ struct event_base;
 class EventLoop
 {
 public:
+	enum EventType {
+		Read = 1,
+		Write = 2,
+	};
+
 	EventLoop();
 	~EventLoop();
 
@@ -28,13 +34,27 @@ public:
 
 	void callLater(const std::function<void()> &func);
 
+	void addEvent(int fd, EventType type,
+		      const std::function<void()> &handler);
+
 private:
+	struct Event {
+		Event(const std::function<void()> &callback);
+		~Event();
+
+		static void dispatch(int fd, short events, void *arg);
+
+		std::function<void()> callback_;
+		struct event *event_;
+	};
+
 	static EventLoop *instance_;
 
 	struct event_base *base_;
 	int exitCode_;
 
 	std::list<std::function<void()>> calls_;
+	std::list<std::unique_ptr<Event>> events_;
 	std::mutex lock_;
 
 	static void dispatchCallback(evutil_socket_t fd, short flags,