Rework device discovery API

libusb_find_devices and libusb_get_devices are no more

libusb_get_device_list obtains a list of libusb_device structures for all
known devices in the system.

Each libusb_device now has a reference count, defaulting to 1 on
instantiation. The reference count of 1 refers to the fact that it is
present in the list in this scenario.

Opening a device adds a pointer to the libusb_device structure in the
handle, so that also adds a reference. Closing the device removes that
reference.

The function to free the device list can optionally unref all the devices
inside.

In future we will make the libusb_device instances all "global" so that if
the app calls get_device_list twice it actually gets the same libusb_device
structure references back. This way we can start to track disconnects, and
we can investigate adding a unique "session ID" to each libusb_device, an
identifier guaranteed to be unique to that device until reboot.

1 files changed, 5 insertions, 1 deletions

diff --git a/TODO b/TODO
index 68adc12..c4ff9b1 100644
--- a/TODO
+++ b/TODO
@@ -8,6 +8,10 @@ API docs
 isochronous endpoint I/O
 thread safety
 abstraction for cross-platform-ness
+fallback on /proc/bus/usb on linux
+error codes
+assign session ID to each libusb_device
+share libusb_device structures in memory between all get_devices callers
 
 for 1.1 or future
 ==================
@@ -21,6 +25,6 @@ use poll() rather than select()?
 struct libusb_(bulk|control)_transfer or parameters?
 devh in general
 urbh in general (should this be a transfer handle?)
-find/get devices API
 config struct/function naming
 typedef _cb or _cb_fn or _cb_t?
+typedef as-is or pointers? libusb_dev_t rather than libusb_dev *?