libusb wrapper workaround for Clang constexpr fails

src/pc/protocols/wrap_libusb.cpp

@@ -0,0 +1,27 @@
+/*
+    dp::libusb - C++ wrapper for libusb-1.0 (focused on use with the XLink protocol)
+
+    Copyright 2023 Dale Phurrough
+
+    Licensed under the Apache License, Version 2.0 (the "License");
+    you may not use this file except in compliance with the License.
+    You may obtain a copy of the License at
+
+        http://www.apache.org/licenses/LICENSE-2.0
+
+    Unless required by applicable law or agreed to in writing, software
+    distributed under the License is distributed on an "AS IS" BASIS,
+    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+    See the License for the specific language governing permissions and
+    limitations under the License.
+*/
+
+#include "wrap_libusb.hpp"
+
+std::mutex dp::libusb::device_list::mtx;
+
+// definition outside class to workaround Clang constexpr failures
+constexpr int dp::libusb::device_handle::DEFAULT_CHUNK_SIZE;
+constexpr int dp::libusb::device_handle::DEFAULT_CHUNK_SIZE_USB1;
+constexpr decltype(libusb_endpoint_descriptor::wMaxPacketSize) dp::libusb::device_handle::DEFAULT_MAX_PACKET_SIZE;
+constexpr std::array<decltype(libusb_endpoint_descriptor::wMaxPacketSize), 32> dp::libusb::device_handle::DEFAULT_MAX_PACKET_ARRAY;

src/pc/protocols/wrap_libusb.hpp

@@ -21,6 +21,7 @@
 
 // project
 #define MVLOG_UNIT_NAME xLinkUsb
+#include "XLink/XLinkLog.h"
 
 // libraries
 #ifdef XLINK_LIBUSB_LOCAL
@@ -273,9 +274,6 @@ class device_list {
     pointer deviceList{};
 };
 
-// TODO move to dedicated cpp file to avoid multiple definitions
-std::mutex device_list::mtx;
-
 // wraps libusb_config_descriptor* and automatically libusb_free_config_descriptor() on destruction
 class config_descriptor : public unique_resource_ptr<libusb_config_descriptor, libusb_free_config_descriptor> {
 public:
@@ -534,7 +532,7 @@ class device_handle : public unique_resource_ptr<libusb_device_handle, libusb_cl
     int control_transfer(uint8_t requestType, uint8_t request, uint16_t value, uint16_t index, void *data, uint16_t length, std::chrono::milliseconds timeout) const noexcept(!Throw) {
         return call_log_throw<Loglevel, Throw>(__func__, __LINE__, libusb_control_transfer, get(), requestType, request, value, index, static_cast<unsigned char*>(data), length, static_cast<unsigned int>(timeout.count()));
     }
-    };
+};
 
 class usb_device : public unique_resource_ptr<libusb_device, libusb_unref_device> {
 private: