Add support for generic events using Linux eventfd

Signed-off-by: Joachim Nilsson <troglobit@gmail.com>

src/event.c

@@ -0,0 +1,106 @@
+/* libuEv - Micro event loop library
+ *
+ * Copyright (c) 2012       Flemming Madsen <flemming!madsen()madsensoft!dk>
+ * Copyright (c) 2013-2017  Joachim Nilsson <troglobit()gmail!com>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include <errno.h>
+#include <sys/eventfd.h>
+#include <unistd.h>		/* close(), read() */
+
+#include "uev.h"
+
+
+/**
+ * Create a generic event watcher
+ * @param ctx    A valid libuEv context
+ * @param w      Pointer to an uev_t watcher
+ * @param cb     Callback when an event is posted
+ * @param arg    Optional callback argument
+ *
+ * @return POSIX OK(0) or non-zero with @param errno set on error.
+ */
+int uev_event_init(uev_ctx_t *ctx, uev_t *w, uev_cb_t *cb, void *arg)
+{
+	int fd;
+
+	if (!w || !ctx) {
+		errno = EINVAL;
+		return -1;
+	}
+	w->fd = -1;
+
+	fd = eventfd(0, EFD_NONBLOCK | EFD_CLOEXEC);
+	if (fd < 0)
+		return -1;
+
+	return _uev_watcher_init(ctx, w, UEV_EVENT_TYPE, cb, arg, fd, UEV_READ)
+		|| _uev_watcher_start(w);
+}
+
+/**
+ * Post a generic event
+ * @param w  Watcher to post to
+ *
+ * @return POSIX OK(0) or non-zero with @param errno set on error.
+ */
+int uev_event_post(uev_t *w)
+{
+	uint64_t val = 1;
+
+	if (!w || -1 == w->fd) {
+		errno = EINVAL;
+		return -1;
+	}
+
+
+	if (write(w->fd, &val, sizeof(val)) != sizeof(val))
+		return -1;
+
+	return 0;
+}
+
+/**
+ * Stop a generic event watcher
+ * @param w  Watcher to stop
+ *
+ * @return POSIX OK(0) or non-zero with @param errno set on error.
+ */
+int uev_event_stop(uev_t *w)
+{
+	if (!_uev_watcher_active(w))
+		return 0;
+
+	if (_uev_watcher_stop(w))
+		return -1;
+
+	close(w->fd);
+	w->fd = -1;
+
+	return 0;
+}
+
+/**
+ * Local Variables:
+ *  indent-tabs-mode: t
+ *  c-file-style: "linux"
+ * End:
+ */