hotplug: Added libusb_hotplug_get_user_data()

Closes #380

[dickens] Fixed up API version in doxygen, whitespace issues, function
visibility annotation (can't use API_EXPORTED for pointer values) and
added new function to libusb-1.0.defs

Signed-off-by: Chris Dickens <christopher.a.dickens@gmail.com>

1 files changed, 27 insertions, 0 deletions

diff --git a/libusb/hotplug.c b/libusb/hotplug.c
index a4320bc..3ccdc2f 100644
--- a/libusb/hotplug.c
+++ b/libusb/hotplug.c
@@ -356,6 +356,33 @@ void API_EXPORTED libusb_hotplug_deregister_callback(struct libusb_context *ctx,
 	}
 }
 
+DEFAULT_VISIBILITY
+void * LIBUSB_CALL libusb_hotplug_get_user_data(struct libusb_context *ctx,
+	libusb_hotplug_callback_handle callback_handle)
+{
+	struct libusb_hotplug_callback *hotplug_cb;
+	void *user_data = NULL;
+
+	/* check for hotplug support */
+	if (!libusb_has_capability(LIBUSB_CAP_HAS_HOTPLUG)) {
+		return NULL;
+	}
+
+	USBI_GET_CONTEXT(ctx);
+
+	usbi_dbg("get hotplug user data %d", callback_handle);
+
+	usbi_mutex_lock(&ctx->hotplug_cbs_lock);
+	list_for_each_entry(hotplug_cb, &ctx->hotplug_cbs, list, struct libusb_hotplug_callback) {
+		if (callback_handle == hotplug_cb->handle) {
+			user_data = hotplug_cb->user_data;
+		}
+	}
+	usbi_mutex_unlock(&ctx->hotplug_cbs_lock);
+
+	return user_data;
+}
+
 void usbi_hotplug_deregister(struct libusb_context *ctx, int forced)
 {
 	struct libusb_hotplug_callback *hotplug_cb, *next;