From baa0cd682aa219c4e16c6a7a8c3143931754ee01 Mon Sep 17 00:00:00 2001
From: Robin Krahl <robin.krahl@ireas.org>
Date: Mon, 18 Feb 2019 17:26:33 +0000
Subject: Simplify handling of GET_DESCRIPTOR requests

Previously, we used the ControlIn::accept method and copied the
generated buffer returned by HidDevice::report_descriptor to the buffer
provided by usb_device::UsbClass in get_report_descriptor.  But it is
easier to directly pass the returned buffer to ControlIn::accept_with,
so we drop the get_report_descriptor method.
---
 src/hid.rs | 21 +++------------------
 1 file changed, 3 insertions(+), 18 deletions(-)

diff --git a/src/hid.rs b/src/hid.rs
index 79ba7f0..48c683b 100644
--- a/src/hid.rs
+++ b/src/hid.rs
@@ -101,21 +101,6 @@ impl<B: UsbBus, D: HidDevice> HidClass<'_, B, D> {
         }
     }
 
-    fn get_report_descriptor(&self, index: u8, buf: &mut [u8]) -> usb_device::Result<usize> {
-        if index == 0 {
-            let report_descriptor = self.device.report_descriptor();
-            let len = report_descriptor.len();
-            if len > buf.len() {
-                Err(UsbError::BufferOverflow)
-            } else {
-                buf[0..len].copy_from_slice(report_descriptor);
-                Ok(len)
-            }
-        } else {
-            Err(UsbError::InvalidState)
-        }
-    }
-
     fn get_report(&mut self, xfer: ControlIn<B>) {
         let req = xfer.request();
         let [report_type, report_id] = req.value.to_be_bytes();
@@ -202,9 +187,9 @@ impl<B: UsbBus, D: HidDevice> UsbClass<B> for HidClass<'_, B, D> {
             (RequestType::Standard, Recipient::Interface) => {
                 if req.request == control::Request::GET_DESCRIPTOR {
                     let (dtype, index) = req.descriptor_type_index();
-                    if dtype == DescriptorType::Report.into() {
-                        xfer.accept(|mut buf| self.get_report_descriptor(index, &mut buf))
-                            .ok();
+                    if dtype == DescriptorType::Report.into() && index == 0 {
+                        let descriptor = self.device.report_descriptor();
+                        xfer.accept_with(descriptor).ok();
                     }
                 }
             }
-- 
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