1 files changed, 133 insertions, 0 deletions
diff --git a/evdev.c b/evdev.c
new file mode 100644
index 0000000..2d179d2
--- /dev/null
+++ b/evdev.c
@@ -0,0 +1,133 @@
+#define _GNU_SOURCE
+
+#include <stdint.h>
+#include <stdbool.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <fcntl.h>
+
+#include <sys/ioctl.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+
+#include <linux/input.h>
+
+#include <pthread.h>
+
+#include <jack/ringbuffer.h>
+
+#include "evdev.h"
+
+typedef struct applause_evdev {
+	int			fd;
+	jack_ringbuffer_t	*buffer;
+	pthread_t		thread;
+} applause_evdev;
+
+char *
+applause_evdev_getname(const char *node)
+{
+	int rc, fd;
+
+	fd = open(node, O_RDONLY);
+	if (fd < 0)
+		return NULL;
+
+	char name[256];
+	rc = ioctl(fd, EVIOCGNAME(sizeof(name)), name);
+	close(fd);
+
+	return rc < 0 ? NULL : strdup(name);
+}
+
+static void *
+applause_evdev_thread_cb(void *userdata)
+{
+	applause_evdev *evdev = userdata;
+
+	for (;;) {
+		struct input_event event;
+		applause_evdev_sample sample;
+
+		/*
+		 * FIXME: How to detect thread cancellation reliably?
+		 */
+		if (read(evdev->fd, &event, sizeof(event)) != sizeof(event))
+			break;
+
+		/*
+		 * FIXME: Why do we get one "empty" event after each successful read?
+		 */
+		if (event.type == 0)
+			continue;
+
+		sample.type = event.type;
+		sample.code = event.code;
+		sample.value = event.value;
+		jack_ringbuffer_write(evdev->buffer, (const char *)&sample, sizeof(sample));
+	}
+
+	/* never reached */
+	return NULL;
+}
+
+applause_evdev *
+applause_evdev_new(const char *node, bool grab)
+{
+	applause_evdev *evdev = calloc(1, sizeof(applause_evdev));
+	if (!evdev)
+		return NULL;
+
+	evdev->fd = open(node, O_RDONLY);
+	if (evdev->fd < 0)
+		goto error;
+
+	/*
+	 * This will fail if the device is already grabbed
+	 * which makes sense since you cannot receive events for such a device.
+	 */
+	if (grab && ioctl(evdev->fd, EVIOCGRAB, true))
+		goto error;
+
+	evdev->buffer = jack_ringbuffer_create(sizeof(applause_evdev_sample)*1024);
+	if (!evdev->buffer)
+		goto error;
+
+	if (pthread_create(&evdev->thread, NULL, applause_evdev_thread_cb, evdev))
+		goto error;
+
+	return evdev;
+
+error:
+	if (evdev->buffer)
+		jack_ringbuffer_free(evdev->buffer);
+	if (evdev->fd > 0)
+		close(evdev->fd);
+	free(evdev);
+	return NULL;
+}
+
+void
+applause_evdev_pull(applause_evdev *evdev, applause_evdev_sample *sample)
+{
+	memset(sample, 0, sizeof(*sample));
+	jack_ringbuffer_read(evdev->buffer, (char *)sample, sizeof(*sample));
+}
+
+void
+applause_evdev_free(applause_evdev *evdev)
+{
+	/*
+	 * NOTE: It's important to support evdev == NULL so that applause_evdev_free()
+	 * can be passed safely to ffi.gc().
+	 */
+	if (!evdev)
+		return;
+
+	pthread_cancel(evdev->thread);
+	pthread_join(evdev->thread, NULL);
+	jack_ringbuffer_free(evdev->buffer);
+	close(evdev->fd);
+	free(evdev);
+}