Add hotplug support.

The internal API is changing as follows:
 - Adding two new functions. usbi_connect_device, and usbi_disconnect_device.
   Backends must call these functions to add them to the context's device list
   at one of two places: initial enumeration (done at init), and on device
   attach and removal. These functions need to be called once per context.
 - Backends that support hotplug should not provide a get_device_list funtion.
   This function is now deprecated and will likely be removed once all backends
   support hotplug.

The external API is changing as follows:
 - Two new functions have been added to register and deregister callbacks for
   hotplug notification: libusb_hotplug_register_callback(),
   libusb_hotplug_deregister_callback(). Hotplug callbacks are called by
   libusb_handle_events(). Details of the new API can be found in libusb.h.
 - A new capability check has been added to check for hotplug support. See
   LIBUSB_CAP_HAS_HOTPLUG.

Aa suggested by Xiaofan add new example has been added to show how to use
the new external hotplug API. See examples/hotplugtest.c.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>

1 files changed, 9 insertions, 0 deletions

diff --git a/libusb/libusbi.h b/libusb/libusbi.h
index b0cc53e..1b59175 100644
--- a/libusb/libusbi.h
+++ b/libusb/libusbi.h
@@ -224,6 +224,11 @@ struct libusb_context {
 	struct list_head open_devs;
 	usbi_mutex_t open_devs_lock;
 
+	/* A list of registered hotplug callbacks */
+	struct list_head hotplug_cbs;
+	usbi_mutex_t hotplug_cbs_lock;
+	int hotplug_pipe[2];
+
 	/* this is a list of in-flight transfer handles, sorted by timeout
 	 * expiration. URBs to timeout the soonest are placed at the beginning of
 	 * the list, URBs that will time out later are placed after, and urbs with
@@ -290,6 +295,7 @@ struct libusb_device {
 	unsigned long session_data;
 
 	struct libusb_device_descriptor device_descriptor;
+	int attached;
 
 	unsigned char os_priv[0];
 };
@@ -401,6 +407,9 @@ int usbi_device_cache_descriptor(libusb_device *dev);
 int usbi_get_config_index_by_value(struct libusb_device *dev,
 	uint8_t bConfigurationValue, int *idx);
 
+void usbi_connect_device (struct libusb_device *dev);
+void usbi_disconnect_device (struct libusb_device *dev);
+
 /* Internal abstraction for poll (needs struct usbi_transfer on Windows) */
 #if defined(OS_LINUX) || defined(OS_DARWIN) || defined(OS_OPENBSD)
 #include <unistd.h>