Allow user data pointer to be passed through pollfd notification API

3 files changed, 16 insertions, 6 deletions

diff --git a/libusb/io.c b/libusb/io.c
index f2de833..ef6ad9f 100644
--- a/libusb/io.c
+++ b/libusb/io.c
@@ -1634,13 +1634,17 @@ API_EXPORTED int libusb_get_next_timeout(libusb_context *ctx,
  * \param ctx the context to operate on, or NULL for the default context
  * \param added_cb pointer to function for addition notifications
  * \param removed_cb pointer to function for removal notifications
+ * \param user_data User data to be passed back to callbacks (useful for
+ * passing context information)
  */
 API_EXPORTED void libusb_set_pollfd_notifiers(libusb_context *ctx,
-	libusb_pollfd_added_cb added_cb, libusb_pollfd_removed_cb removed_cb)
+	libusb_pollfd_added_cb added_cb, libusb_pollfd_removed_cb removed_cb,
+	void *user_data)
 {
 	USBI_GET_CONTEXT(ctx);
 	ctx->fd_added_cb = added_cb;
 	ctx->fd_removed_cb = removed_cb;
+	ctx->fd_cb_user_data = user_data;
 }
 
 /* Add a file descriptor to the list of file descriptors to be monitored.
@@ -1660,7 +1664,7 @@ int usbi_add_pollfd(struct libusb_context *ctx, int fd, short events)
 	pthread_mutex_unlock(&ctx->pollfds_lock);
 
 	if (ctx->fd_added_cb)
-		ctx->fd_added_cb(fd, events);
+		ctx->fd_added_cb(fd, events, ctx->fd_cb_user_data);
 	return 0;
 }
 
@@ -1688,7 +1692,7 @@ void usbi_remove_pollfd(struct libusb_context *ctx, int fd)
 	pthread_mutex_unlock(&ctx->pollfds_lock);
 	free(ipollfd);
 	if (ctx->fd_removed_cb)
-		ctx->fd_removed_cb(fd);
+		ctx->fd_removed_cb(fd, ctx->fd_cb_user_data);
 }
 
 /** \ingroup poll
diff --git a/libusb/libusb.h b/libusb/libusb.h
index 20d1988..685a1c8 100644
--- a/libusb/libusb.h
+++ b/libusb/libusb.h
@@ -1166,22 +1166,27 @@ struct libusb_pollfd {
  * \param fd the new file descriptor
  * \param events events to monitor for, see \ref libusb_pollfd for a
  * description
+ * \param user_data User data pointer specified in
+ * libusb_set_pollfd_notifiers() call
  * \see libusb_set_pollfd_notifiers()
  */
-typedef void (*libusb_pollfd_added_cb)(int fd, short events);
+typedef void (*libusb_pollfd_added_cb)(int fd, short events, void *user_data);
 
 /** \ingroup poll
  * Callback function, invoked when a file descriptor should be removed from
  * the set of file descriptors being monitored for events. After returning
  * from this callback, do not use that file descriptor again.
  * \param fd the file descriptor to stop monitoring
+ * \param user_data User data pointer specified in
+ * libusb_set_pollfd_notifiers() call
  * \see libusb_set_pollfd_notifiers()
  */
-typedef void (*libusb_pollfd_removed_cb)(int fd);
+typedef void (*libusb_pollfd_removed_cb)(int fd, void *user_data);
 
 const struct libusb_pollfd **libusb_get_pollfds(libusb_context *ctx);
 void libusb_set_pollfd_notifiers(libusb_context *ctx,
-	libusb_pollfd_added_cb added_cb, libusb_pollfd_removed_cb removed_cb);
+	libusb_pollfd_added_cb added_cb, libusb_pollfd_removed_cb removed_cb,
+	void *user_data);
 
 #ifdef __cplusplus
 }
diff --git a/libusb/libusbi.h b/libusb/libusbi.h
index 8eb4c5c..ec79a20 100644
--- a/libusb/libusbi.h
+++ b/libusb/libusbi.h
@@ -166,6 +166,7 @@ struct libusb_context {
 	/* user callbacks for pollfd changes */
 	libusb_pollfd_added_cb fd_added_cb;
 	libusb_pollfd_removed_cb fd_removed_cb;
+	void *fd_cb_user_data;
 
 	/* ensures that only one thread is handling events at any one time */
 	pthread_mutex_t events_lock;