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Add DeviceHandle::into_raw()
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As exotic as it may be, libusbredir requires to give the device handle
ownership to the library. This function helps to achieve this, without
having to leak the a DeviceHandle with mem::forget.

Signed-off-by: Marc-André Lureau <[email protected]>
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@elmarco
elmarco committed Aug 1, 2021
1 parent 009254b commit eaac734
Showing 1 changed file with 39 additions and 25 deletions.
64 changes: 39 additions & 25 deletions src/device_handle.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -107,7 +107,7 @@ impl<'a> Iterator for ClaimedInterfacesIter<'a> {
#[derive(Eq, PartialEq)]
pub struct DeviceHandle<T: UsbContext> {
context: T,
handle: NonNull<libusb_device_handle>,
handle: Option<NonNull<libusb_device_handle>>,
interfaces: ClaimedInterfaces,
}

Expand All @@ -116,10 +116,12 @@ impl<T: UsbContext> Drop for DeviceHandle<T> {
fn drop(&mut self) {
unsafe {
for iface in self.interfaces.iter() {
libusb_release_interface(self.handle.as_ptr(), iface as c_int);
libusb_release_interface(self.as_raw(), iface as c_int);
}

libusb_close(self.handle.as_ptr());
if self.handle.is_some() {
libusb_close(self.as_raw());
}
}
}
}
Expand All @@ -143,7 +145,19 @@ impl<T: UsbContext> DeviceHandle<T> {
/// This structure tracks claimed interfaces, and will get out if sync if interfaces are
/// manipulated externally. Use only libusb endpoint IO functions.
pub fn as_raw(&self) -> *mut libusb_device_handle {
self.handle.as_ptr()
// Safety: handle is Some() after initialization
self.handle.unwrap().as_ptr()
}

/// Consumes the `DeviceHandle`, returning the raw libusb_device_handle
/// pointer, for advanced use in unsafe code.
///
/// # Safety
///
/// Panics if you have any claimed interfaces on this handle.
pub fn into_raw(mut self) -> *mut libusb_device_handle {
assert_eq!(self.interfaces.size(), 0);
self.handle.take().unwrap().as_ptr()
}

/// Get the context associated with this device
Expand All @@ -156,7 +170,7 @@ impl<T: UsbContext> DeviceHandle<T> {
unsafe {
device::Device::from_libusb(
self.context.clone(),
std::ptr::NonNull::new_unchecked(libusb_get_device(self.handle.as_ptr())),
std::ptr::NonNull::new_unchecked(libusb_get_device(self.as_raw())),
)
}
}
Expand All @@ -171,7 +185,7 @@ impl<T: UsbContext> DeviceHandle<T> {
) -> DeviceHandle<T> {
DeviceHandle {
context,
handle,
handle: Some(handle),
interfaces: ClaimedInterfaces::new(),
}
}
Expand All @@ -181,7 +195,7 @@ impl<T: UsbContext> DeviceHandle<T> {
let mut config = mem::MaybeUninit::<c_int>::uninit();

try_unsafe!(libusb_get_configuration(
self.handle.as_ptr(),
self.as_raw(),
config.as_mut_ptr()
));
Ok(unsafe { config.assume_init() } as u8)
Expand All @@ -190,35 +204,35 @@ impl<T: UsbContext> DeviceHandle<T> {
/// Sets the device's active configuration.
pub fn set_active_configuration(&mut self, config: u8) -> crate::Result<()> {
try_unsafe!(libusb_set_configuration(
self.handle.as_ptr(),
self.as_raw(),
c_int::from(config)
));
Ok(())
}

/// Puts the device in an unconfigured state.
pub fn unconfigure(&mut self) -> crate::Result<()> {
try_unsafe!(libusb_set_configuration(self.handle.as_ptr(), -1));
try_unsafe!(libusb_set_configuration(self.as_raw(), -1));
Ok(())
}

/// Resets the device.
pub fn reset(&mut self) -> crate::Result<()> {
try_unsafe!(libusb_reset_device(self.handle.as_ptr()));
try_unsafe!(libusb_reset_device(self.as_raw()));
Ok(())
}

/// Clear the halt/stall condition for an endpoint.
pub fn clear_halt(&mut self, endpoint: u8) -> crate::Result<()> {
try_unsafe!(libusb_clear_halt(self.handle.as_ptr(), endpoint));
try_unsafe!(libusb_clear_halt(self.as_raw(), endpoint));
Ok(())
}

/// Indicates whether the device has an attached kernel driver.
///
/// This method is not supported on all platforms.
pub fn kernel_driver_active(&self, iface: u8) -> crate::Result<bool> {
match unsafe { libusb_kernel_driver_active(self.handle.as_ptr(), c_int::from(iface)) } {
match unsafe { libusb_kernel_driver_active(self.as_raw(), c_int::from(iface)) } {
0 => Ok(false),
1 => Ok(true),
err => Err(error::from_libusb(err)),
Expand All @@ -230,7 +244,7 @@ impl<T: UsbContext> DeviceHandle<T> {
/// This method is not supported on all platforms.
pub fn detach_kernel_driver(&mut self, iface: u8) -> crate::Result<()> {
try_unsafe!(libusb_detach_kernel_driver(
self.handle.as_ptr(),
self.as_raw(),
c_int::from(iface)
));
Ok(())
Expand All @@ -241,7 +255,7 @@ impl<T: UsbContext> DeviceHandle<T> {
/// This method is not supported on all platforms.
pub fn attach_kernel_driver(&mut self, iface: u8) -> crate::Result<()> {
try_unsafe!(libusb_attach_kernel_driver(
self.handle.as_ptr(),
self.as_raw(),
c_int::from(iface)
));
Ok(())
Expand All @@ -258,7 +272,7 @@ impl<T: UsbContext> DeviceHandle<T> {
/// this function was never called.
pub fn set_auto_detach_kernel_driver(&mut self, auto_detach: bool) -> crate::Result<()> {
try_unsafe!(libusb_set_auto_detach_kernel_driver(
self.handle.as_ptr(),
self.as_raw(),
auto_detach.into()
));
Ok(())
Expand All @@ -270,7 +284,7 @@ impl<T: UsbContext> DeviceHandle<T> {
/// when the device handle goes out of scope.
pub fn claim_interface(&mut self, iface: u8) -> crate::Result<()> {
try_unsafe!(libusb_claim_interface(
self.handle.as_ptr(),
self.as_raw(),
c_int::from(iface)
));
self.interfaces.insert(iface);
Expand All @@ -280,7 +294,7 @@ impl<T: UsbContext> DeviceHandle<T> {
/// Releases a claimed interface.
pub fn release_interface(&mut self, iface: u8) -> crate::Result<()> {
try_unsafe!(libusb_release_interface(
self.handle.as_ptr(),
self.as_raw(),
c_int::from(iface)
));
self.interfaces.remove(iface);
Expand All @@ -290,7 +304,7 @@ impl<T: UsbContext> DeviceHandle<T> {
/// Sets an interface's active setting.
pub fn set_alternate_setting(&mut self, iface: u8, setting: u8) -> crate::Result<()> {
try_unsafe!(libusb_set_interface_alt_setting(
self.handle.as_ptr(),
self.as_raw(),
c_int::from(iface),
c_int::from(setting)
));
Expand Down Expand Up @@ -331,7 +345,7 @@ impl<T: UsbContext> DeviceHandle<T> {
let mut transferred = mem::MaybeUninit::<c_int>::uninit();
unsafe {
match libusb_interrupt_transfer(
self.handle.as_ptr(),
self.as_raw(),
endpoint,
buf.as_mut_ptr() as *mut c_uchar,
buf.len() as c_int,
Expand Down Expand Up @@ -384,7 +398,7 @@ impl<T: UsbContext> DeviceHandle<T> {
let mut transferred = mem::MaybeUninit::<c_int>::uninit();
unsafe {
match libusb_interrupt_transfer(
self.handle.as_ptr(),
self.as_raw(),
endpoint,
buf.as_ptr() as *mut c_uchar,
buf.len() as c_int,
Expand Down Expand Up @@ -439,7 +453,7 @@ impl<T: UsbContext> DeviceHandle<T> {
let mut transferred = mem::MaybeUninit::<c_int>::uninit();
unsafe {
match libusb_bulk_transfer(
self.handle.as_ptr(),
self.as_raw(),
endpoint,
buf.as_mut_ptr() as *mut c_uchar,
buf.len() as c_int,
Expand Down Expand Up @@ -487,7 +501,7 @@ impl<T: UsbContext> DeviceHandle<T> {
let mut transferred = mem::MaybeUninit::<c_int>::uninit();
unsafe {
match libusb_bulk_transfer(
self.handle.as_ptr(),
self.as_raw(),
endpoint,
buf.as_ptr() as *mut c_uchar,
buf.len() as c_int,
Expand Down Expand Up @@ -549,7 +563,7 @@ impl<T: UsbContext> DeviceHandle<T> {
}
let res = unsafe {
libusb_control_transfer(
self.handle.as_ptr(),
self.as_raw(),
request_type,
request,
value,
Expand Down Expand Up @@ -607,7 +621,7 @@ impl<T: UsbContext> DeviceHandle<T> {
}
let res = unsafe {
libusb_control_transfer(
self.handle.as_ptr(),
self.as_raw(),
request_type,
request,
value,
Expand Down Expand Up @@ -668,7 +682,7 @@ impl<T: UsbContext> DeviceHandle<T> {
let capacity = buf.capacity() as i32;

let res = unsafe {
libusb_get_string_descriptor_ascii(self.handle.as_ptr(), index, ptr, capacity)
libusb_get_string_descriptor_ascii(self.as_raw(), index, ptr, capacity)
};

if res < 0 {
Expand Down

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