reduced the number of #[cfg] attributes by using cfg-if

Cargo.toml

@@ -42,6 +42,7 @@ windows-native = [
 
 [dependencies]
 libc = "0.2"
+cfg-if = "1"
 
 [target.'cfg(target_os = "linux")'.dependencies]
 udev = { version = "0.7", optional = true }

src/lib.rs

@@ -58,44 +58,68 @@
 //! [`HidDevice`] handles can access the same physical device. For backward compatibility this is
 //! an opt-in that can be enabled with the `macos-shared-device` feature flag.
 
-#[cfg(target_os = "windows")]
-use windows_sys::core::GUID;
-
 mod error;
 mod ffi;
 
-#[cfg(hidapi)]
-mod hidapi;
-
-#[cfg(all(feature = "linux-native", target_os = "linux"))]
-#[cfg_attr(docsrs, doc(cfg(all(feature = "linux-native", target_os = "linux"))))]
-mod linux_native;
-#[cfg(target_os = "macos")]
-#[cfg_attr(docsrs, doc(cfg(target_os = "macos")))]
-mod macos;
-#[cfg(target_os = "windows")]
-#[cfg_attr(docsrs, doc(cfg(target_os = "windows")))]
-mod windows;
-
-#[cfg(feature = "windows-native")]
-#[cfg_attr(docsrs, doc(cfg(all(feature = "windows-native", target_os = "windows"))))]
-mod windows_native;
-
 use libc::wchar_t;
 use std::ffi::CStr;
 use std::ffi::CString;
 use std::fmt;
 use std::fmt::Debug;
 use std::sync::Mutex;
+use cfg_if::cfg_if;
 
 pub use error::HidError;
 
-#[cfg(hidapi)]
-use crate::hidapi::HidApiBackend;
-#[cfg(all(feature = "linux-native", target_os = "linux"))]
-use linux_native::HidApiBackend;
-#[cfg(all(feature = "windows-native", target_os = "windows"))]
-use windows_native::HidApiBackend;
+cfg_if! {
+    if #[cfg(all(feature = "linux-native", target_os = "linux"))] {
+        //#[cfg_attr(docsrs, doc(cfg(all(feature = "linux-native", target_os = "linux"))))]
+        mod linux_native;
+        use linux_native::HidApiBackend;
+    } else if #[cfg(all(feature = "windows-native", target_os = "windows"))] {
+        //#[cfg_attr(docsrs, doc(cfg(all(feature = "windows-native", target_os = "windows"))))]
+        mod windows_native;
+        use windows_native::HidApiBackend;
+    } else if #[cfg(hidapi)] {
+        mod hidapi;
+        use hidapi::HidApiBackend;
+    } else {
+        compile_error!("No backend selected");
+    }
+}
+
+// Automatically implement the top trait
+cfg_if! {
+    if #[cfg(target_os = "windows")] {
+        #[cfg_attr(docsrs, doc(cfg(target_os = "windows")))]
+        mod windows;
+        use windows::GUID;
+        /// A trait with the extra methods that are available on Windows
+        trait HidDeviceBackendWindows {
+            /// Get the container ID for a HID device
+            fn get_container_id(&self) -> HidResult<GUID>;
+        }
+        trait HidDeviceBackend: HidDeviceBackendBase + HidDeviceBackendWindows + Send {}
+        impl<T> HidDeviceBackend for T where T: HidDeviceBackendBase + HidDeviceBackendWindows + Send {}
+    } else if #[cfg(target_os = "macos")] {
+        #[cfg_attr(docsrs, doc(cfg(target_os = "macos")))]
+        mod macos;
+        /// A trait with the extra methods that are available on macOS
+        trait HidDeviceBackendMacos {
+            /// Get the location ID for a [`HidDevice`] device.
+            fn get_location_id(&self) -> HidResult<u32>;
+
+            /// Check if the device was opened in exclusive mode.
+            fn is_open_exclusive(&self) -> HidResult<bool>;
+        }
+        trait HidDeviceBackend: HidDeviceBackendBase + HidDeviceBackendMacos + Send {}
+        impl<T> HidDeviceBackend for T where T: HidDeviceBackendBase + HidDeviceBackendMacos + Send {}
+    } else {
+        trait HidDeviceBackend: HidDeviceBackendBase + Send {}
+        impl<T> HidDeviceBackend for T where T: HidDeviceBackendBase + Send {}
+    }
+}
+
 
 pub type HidResult<T> = Result<T, HidError>;
 pub const MAX_REPORT_DESCRIPTOR_SIZE: usize = 4096;
@@ -463,42 +487,6 @@ trait HidDeviceBackendBase {
     }
 }
 
-/// A trait with the extra methods that are available on macOS
-#[cfg(target_os = "macos")]
-trait HidDeviceBackendMacos {
-    /// Get the location ID for a [`HidDevice`] device.
-    fn get_location_id(&self) -> HidResult<u32>;
-
-    /// Check if the device was opened in exclusive mode.
-    fn is_open_exclusive(&self) -> HidResult<bool>;
-}
-
-/// A trait with the extra methods that are available on macOS
-#[cfg(target_os = "windows")]
-trait HidDeviceBackendWindows {
-    /// Get the container ID for a HID device
-    fn get_container_id(&self) -> HidResult<GUID>;
-}
-
-#[cfg(not(any(target_os = "macos", target_os = "windows")))]
-trait HidDeviceBackend: HidDeviceBackendBase + Send {}
-#[cfg(target_os = "macos")]
-trait HidDeviceBackend: HidDeviceBackendBase + HidDeviceBackendMacos + Send {}
-#[cfg(target_os = "windows")]
-trait HidDeviceBackend: HidDeviceBackendBase + HidDeviceBackendWindows + Send {}
-
-/// Automatically implement the top trait
-#[cfg(not(any(target_os = "macos", target_os = "windows")))]
-impl<T> HidDeviceBackend for T where T: HidDeviceBackendBase + Send {}
-
-/// Automatically implement the top trait
-#[cfg(target_os = "macos")]
-impl<T> HidDeviceBackend for T where T: HidDeviceBackendBase + HidDeviceBackendMacos + Send {}
-
-/// Automatically implement the top trait
-#[cfg(target_os = "windows")]
-impl<T> HidDeviceBackend for T where T: HidDeviceBackendBase + HidDeviceBackendWindows + Send {}
-
 pub struct HidDevice {
     inner: Box<dyn HidDeviceBackend>,
 }

src/windows.rs

@@ -1,4 +1,4 @@
-use windows_sys::core::GUID;
+pub use windows_sys::core::GUID;
 use crate::{HidDevice, HidResult};
 
 impl HidDevice {

src/windows_native/descriptor/mod.rs

@@ -8,7 +8,6 @@ mod tests;
 use std::collections::HashMap;
 use std::ffi::c_void;
 use std::slice;
-use crate::ensure;
 use encoder::encode_descriptor;
 use typedefs::{Caps, HidpPreparsedData, LinkCollectionNode};
 use types::{BitRange, ItemNodeType, MainItemNode, MainItems, ReportType};

src/windows_native/dev_node.rs

@@ -1,6 +1,5 @@
 use std::ptr::null_mut;
 use windows_sys::Win32::Devices::DeviceAndDriverInstallation::{CM_Get_DevNode_PropertyW, CM_Get_Parent, CM_LOCATE_DEVNODE_NORMAL, CM_Locate_DevNodeW, CR_BUFFER_SMALL, CR_SUCCESS};
-use crate::ensure;
 use super::error::{check_config, WinError, WinResult};
 use super::string::U16Str;
 use super::types::{DeviceProperty, PropertyKey};

src/windows_native/hid.rs

@@ -2,7 +2,6 @@ use std::ffi::c_void;
 use std::mem::{size_of, zeroed};
 use windows_sys::core::GUID;
 use windows_sys::Win32::Devices::HumanInterfaceDevice::{HIDD_ATTRIBUTES, HidD_FreePreparsedData, HidD_GetAttributes, HidD_GetHidGuid, HidD_GetPreparsedData, HIDP_CAPS, HidP_GetCaps, HIDP_STATUS_SUCCESS};
-use crate::ensure;
 use super::error::{check_boolean, WinError, WinResult};
 use super::types::Handle;
 

src/windows_native/interfaces.rs

@@ -1,7 +1,6 @@
 use std::ptr::{null, null_mut};
 use windows_sys::core::GUID;
 use windows_sys::Win32::Devices::DeviceAndDriverInstallation::{CM_GET_DEVICE_INTERFACE_LIST_PRESENT, CM_Get_Device_Interface_List_SizeW, CM_Get_Device_Interface_ListW, CM_Get_Device_Interface_PropertyW, CR_BUFFER_SMALL, CR_SUCCESS};
-use crate::ensure;
 use super::error::{check_config, WinError, WinResult};
 use super::hid::get_interface_guid;
 use super::string::{U16Str, U16StringList};

src/windows_native/mod.rs

@@ -1,4 +1,12 @@
-//! The implementation which uses the C library to perform operations
+//! The implementation which directly uses the win32 api to perform operations
+
+macro_rules! ensure {
+    ($cond:expr, $result:expr) => {
+        if !($cond) {
+            return $result;
+        }
+    };
+}
 
 mod types;
 mod error;
@@ -35,16 +43,6 @@ use types::{Handle, Overlapped};
 
 const STRING_BUF_LEN: usize = 128;
 
-#[macro_export]
-macro_rules! ensure {
-    ($cond:expr, $result:expr) => {
-        if !($cond) {
-            return $result;
-        }
-    };
-}
-
-
 pub struct HidApiBackend;
 impl HidApiBackend {
     pub fn get_hid_device_info_vector(vid: u16, pid: u16) -> HidResult<Vec<DeviceInfo>> {

src/windows_native/types.rs

@@ -6,7 +6,7 @@ use windows_sys::Win32::Foundation::{CloseHandle, FALSE, HANDLE, INVALID_HANDLE_
 use windows_sys::Win32::System::IO::{GetOverlappedResultEx, OVERLAPPED};
 use windows_sys::Win32::System::Threading::{CreateEventW, INFINITE};
 use windows_sys::Win32::UI::Shell::PropertiesSystem::PROPERTYKEY;
-use crate::{BusType, ensure};
+use crate::BusType;
 use super::error::{WinError, WinResult};
 
 #[allow(clippy::missing_safety_doc)]