Make handle fields const (#1468)

.github/readme.md

@@ -75,16 +75,18 @@ features = [
 Make use of any Windows APIs as needed.
 
 ```rust
-use windows_sys::{Win32::Foundation::*, Win32::System::Threading::*, Win32::UI::WindowsAndMessaging::*};
+use windows_sys::{
+    Win32::Foundation::*, Win32::System::Threading::*, Win32::UI::WindowsAndMessaging::*,
+};
 
 fn main() {
     unsafe {
-        let event = CreateEventW(std::ptr::null_mut(), 1, 0, std::ptr::null_mut());
+        let event = CreateEventW(std::ptr::null(), 1, 0, std::ptr::null());
         SetEvent(event);
         WaitForSingleObject(event, 0);
         CloseHandle(event);
 
-        MessageBoxA(0, b"Text\0".as_ptr() as _, b"Caption\0".as_ptr() as _, MB_OK);
+        MessageBoxA(0, b"Text\0".as_ptr(), b"Caption\0".as_ptr(), MB_OK);
     }
 }
 ```

crates/libs/bindgen/src/functions.rs

@@ -38,7 +38,7 @@ pub fn gen_function(def: &MethodDef, gen: &Gen) -> TokenStream {
     }
 }
 
-fn gen_function_if(entry: &Vec<ElementType>, gen: &Gen) -> TokenStream {
+fn gen_function_if(entry: &[ElementType], gen: &Gen) -> TokenStream {
     let mut tokens = TokenStream::new();
 
     for def in entry {

crates/libs/bindgen/src/gen.rs

@@ -116,10 +116,8 @@ impl Gen<'_> {
     }
 
     fn add_namespace(&self, namespace: &'static str, namespaces: &mut BTreeSet<&'static str>) {
-        if !namespace.is_empty() && namespace != self.namespace {
-            if !self.namespace.starts_with(format!("{}.", namespace).as_str()) {
-                namespaces.insert(namespace);
-            }
+        if !namespace.is_empty() && namespace != self.namespace && !self.namespace.starts_with(format!("{}.", namespace).as_str()) {
+            namespaces.insert(namespace);
         }
     }
 

crates/libs/bindgen/src/handles.rs

@@ -79,6 +79,10 @@ pub fn gen_win_handle(def: &TypeDef, gen: &Gen) -> TokenStream {
 }
 
 fn gen_signature(def: &TypeDef, gen: &Gen) -> TokenStream {
-    let signature = def.fields().next().map(|field| field.signature(Some(def))).unwrap();
+    let mut signature = def.fields().next().map(|field| field.signature(Some(def))).unwrap();
+    // Handle fields don't need to be mutable and it's easier to work with handles when
+    // they're `*const` rather than `*mut`. This mainly affects string handle types
+    // like PWSTR/PSTR/BSTR.
+    signature.is_const = true;
     gen_sig(&signature, gen)
 }

crates/libs/bindgen/src/implements.rs

@@ -102,6 +102,7 @@ pub fn gen(def: &TypeDef, gen: &Gen) -> TokenStream {
 
     for method in def.methods() {
         let name = method_names.add(&method);
+        // TODO: can we use core::ptr::addr_of to avoid the need for const_fn_fn_ptr_basics?
         methods.combine(&quote! { #name: #name::<#(#generics)* Identity, Impl, OFFSET>, });
     }
 

crates/libs/bindgen/src/replacements/bstr.rs

@@ -3,7 +3,7 @@ use super::*;
 pub fn gen() -> TokenStream {
     quote! {
         #[repr(transparent)]
-        pub struct BSTR(*mut u16);
+        pub struct BSTR(*const u16);
         impl BSTR {
             pub fn new() -> Self {
                 Self(core::ptr::null_mut())
@@ -28,7 +28,7 @@ pub fn gen() -> TokenStream {
 
                 unsafe {
                     SysAllocStringLen(
-                        PWSTR(value.as_ptr() as *mut _),
+                        PWSTR(value.as_ptr()),
                         value.len() as u32,
                     )
                 }
@@ -39,7 +39,7 @@ pub fn gen() -> TokenStream {
                     return &[];
                 }
 
-                unsafe { ::core::slice::from_raw_parts(self.0 as *const u16, self.len()) }
+                unsafe { ::core::slice::from_raw_parts(self.0, self.len()) }
             }
         }
         impl ::core::clone::Clone for BSTR {
@@ -133,7 +133,6 @@ pub fn gen() -> TokenStream {
         unsafe impl ::windows::core::Abi for BSTR {
             type Abi = ::core::mem::ManuallyDrop<Self>;
         }
-        pub type BSTR_abi = *mut u16;
         #[cfg(feature = "alloc")]
         impl<'a> ::windows::core::IntoParam<'a, BSTR> for &str {
             fn into_param(self) -> ::windows::core::Param<'a, BSTR> {

crates/libs/bindgen/src/replacements/pstr.rs

@@ -4,7 +4,7 @@ use super::*;
 pub fn gen() -> TokenStream {
     quote! {
         #[repr(transparent)]
-        pub struct PSTR(pub *mut u8);
+        pub struct PSTR(pub *const u8);
         impl PSTR {
             pub fn is_null(&self) -> bool {
                 self.0.is_null()
@@ -39,7 +39,7 @@ pub fn gen() -> TokenStream {
             unsafe fn drop_param(param: &mut ::windows::core::Param<'_, Self>) {
                 if let ::windows::core::Param::Boxed(value) = param {
                     if !value.is_null() {
-                        ::windows::core::alloc::boxed::Box::from_raw(value.0);
+                        ::windows::core::alloc::boxed::Box::from_raw(value.0 as *mut u8);
                     }
                 }
             }

crates/libs/bindgen/src/replacements/pwstr.rs

@@ -4,7 +4,7 @@ use super::*;
 pub fn gen() -> TokenStream {
     quote! {
         #[repr(transparent)]
-        pub struct PWSTR(pub *mut u16);
+        pub struct PWSTR(pub *const u16);
         impl PWSTR {
             pub fn is_null(&self) -> bool {
                 self.0.is_null()
@@ -39,7 +39,7 @@ pub fn gen() -> TokenStream {
             unsafe fn drop_param(param: &mut ::windows::core::Param<'_, Self>) {
                 if let ::windows::core::Param::Boxed(value) = param {
                     if !value.is_null() {
-                        ::windows::core::alloc::boxed::Box::from_raw(value.0);
+                        ::windows::core::alloc::boxed::Box::from_raw(value.0 as *mut u16);
                     }
                 }
             }

crates/libs/sys/src/Windows/Win32/Foundation/mod.rs

@@ -121,7 +121,7 @@ impl ::core::clone::Clone for APP_LOCAL_DEVICE_ID {
 pub const APP_LOCAL_DEVICE_ID_SIZE: u32 = 32u32;
 pub type BOOL = i32;
 pub type BOOLEAN = u8;
-pub type BSTR = *mut u16;
+pub type BSTR = *const u16;
 #[doc = "*Required features: 'Win32_Foundation'*"]
 pub const BT_E_SPURIOUS_ACTIVATION: ::windows_sys::core::HRESULT = -2146958592i32;
 #[doc = "*Required features: 'Win32_Foundation'*"]
@@ -4836,8 +4836,8 @@ pub const PSINK_E_LARGE_ATTACHMENT: ::windows_sys::core::HRESULT = -2147215470i3
 pub const PSINK_E_QUERY_ONLY: ::windows_sys::core::HRESULT = -2147215472i32;
 #[doc = "*Required features: 'Win32_Foundation'*"]
 pub const PSINK_S_LARGE_WORD: ::windows_sys::core::HRESULT = 268179i32;
-pub type PSTR = *mut u8;
-pub type PWSTR = *mut u16;
+pub type PSTR = *const u8;
+pub type PWSTR = *const u16;
 #[doc = "*Required features: 'Win32_Foundation'*"]
 pub const QPARSE_E_EXPECTING_BRACE: ::windows_sys::core::HRESULT = -2147215770i32;
 #[doc = "*Required features: 'Win32_Foundation'*"]

crates/libs/sys/src/Windows/Win32/System/Threading/mod.rs

@@ -869,7 +869,7 @@ impl ::core::clone::Clone for IO_COUNTERS {
 }
 #[doc = "*Required features: 'Win32_System_Threading'*"]
 pub type LPFIBER_START_ROUTINE = ::core::option::Option<unsafe extern "system" fn(lpfiberparameter: *mut ::core::ffi::c_void)>;
-pub type LPPROC_THREAD_ATTRIBUTE_LIST = *mut ::core::ffi::c_void;
+pub type LPPROC_THREAD_ATTRIBUTE_LIST = *const ::core::ffi::c_void;
 #[doc = "*Required features: 'Win32_System_Threading'*"]
 pub type LPTHREAD_START_ROUTINE = ::core::option::Option<unsafe extern "system" fn(lpthreadparameter: *mut ::core::ffi::c_void) -> u32>;
 #[doc = "*Required features: 'Win32_System_Threading'*"]

crates/libs/windows/src/Windows/Win32/Foundation/mod.rs

@@ -232,7 +232,7 @@ unsafe impl ::windows::core::Abi for BOOLEAN {
     type Abi = Self;
 }
 #[repr(transparent)]
-pub struct BSTR(*mut u16);
+pub struct BSTR(*const u16);
 impl BSTR {
     pub fn new() -> Self {
         Self(core::ptr::null_mut())
@@ -251,13 +251,13 @@ impl BSTR {
         if value.is_empty() {
             return Self(::core::ptr::null_mut());
         }
-        unsafe { SysAllocStringLen(PWSTR(value.as_ptr() as *mut _), value.len() as u32) }
+        unsafe { SysAllocStringLen(PWSTR(value.as_ptr()), value.len() as u32) }
     }
     pub fn as_wide(&self) -> &[u16] {
         if self.0.is_null() {
             return &[];
         }
-        unsafe { ::core::slice::from_raw_parts(self.0 as *const u16, self.len()) }
+        unsafe { ::core::slice::from_raw_parts(self.0, self.len()) }
     }
 }
 impl ::core::clone::Clone for BSTR {
@@ -348,7 +348,6 @@ impl ::core::ops::Drop for BSTR {
 unsafe impl ::windows::core::Abi for BSTR {
     type Abi = ::core::mem::ManuallyDrop<Self>;
 }
-pub type BSTR_abi = *mut u16;
 #[cfg(feature = "alloc")]
 impl<'a> ::windows::core::IntoParam<'a, BSTR> for &str {
     fn into_param(self) -> ::windows::core::Param<'a, BSTR> {
@@ -5885,7 +5884,7 @@ pub const PSINK_E_QUERY_ONLY: ::windows::core::HRESULT = ::windows::core::HRESUL
 #[doc = "*Required features: 'Win32_Foundation'*"]
 pub const PSINK_S_LARGE_WORD: ::windows::core::HRESULT = ::windows::core::HRESULT(268179i32);
 #[repr(transparent)]
-pub struct PSTR(pub *mut u8);
+pub struct PSTR(pub *const u8);
 impl PSTR {
     pub fn is_null(&self) -> bool {
         self.0.is_null()
@@ -5919,7 +5918,7 @@ unsafe impl ::windows::core::Abi for PSTR {
     unsafe fn drop_param(param: &mut ::windows::core::Param<'_, Self>) {
         if let ::windows::core::Param::Boxed(value) = param {
             if !value.is_null() {
-                ::windows::core::alloc::boxed::Box::from_raw(value.0);
+                ::windows::core::alloc::boxed::Box::from_raw(value.0 as *mut u8);
             }
         }
     }
@@ -5937,7 +5936,7 @@ impl<'a> ::windows::core::IntoParam<'a, PSTR> for ::windows::core::alloc::string
     }
 }
 #[repr(transparent)]
-pub struct PWSTR(pub *mut u16);
+pub struct PWSTR(pub *const u16);
 impl PWSTR {
     pub fn is_null(&self) -> bool {
         self.0.is_null()
@@ -5971,7 +5970,7 @@ unsafe impl ::windows::core::Abi for PWSTR {
     unsafe fn drop_param(param: &mut ::windows::core::Param<'_, Self>) {
         if let ::windows::core::Param::Boxed(value) = param {
             if !value.is_null() {
-                ::windows::core::alloc::boxed::Box::from_raw(value.0);
+                ::windows::core::alloc::boxed::Box::from_raw(value.0 as *mut u16);
             }
         }
     }

crates/libs/windows/src/Windows/Win32/System/Threading/mod.rs

@@ -2735,7 +2735,7 @@ pub unsafe fn IsWow64Process2<'a, Param0: ::windows::core::IntoParam<'a, super::
 pub type LPFIBER_START_ROUTINE = ::core::option::Option<unsafe extern "system" fn(lpfiberparameter: *mut ::core::ffi::c_void)>;
 #[repr(transparent)]
 #[derive(:: core :: cmp :: PartialEq, :: core :: cmp :: Eq)]
-pub struct LPPROC_THREAD_ATTRIBUTE_LIST(pub *mut ::core::ffi::c_void);
+pub struct LPPROC_THREAD_ATTRIBUTE_LIST(pub *const ::core::ffi::c_void);
 impl LPPROC_THREAD_ATTRIBUTE_LIST {
     pub fn is_invalid(&self) -> bool {
         *self == unsafe { ::core::mem::zeroed() }

crates/libs/windows/src/core/bindings.rs

@@ -1176,7 +1176,7 @@ impl<'a> ::windows::core::IntoParam<'a, BOOL> for bool {
     }
 }
 #[repr(transparent)]
-pub struct BSTR(*mut u16);
+pub struct BSTR(*const u16);
 impl BSTR {
     pub fn new() -> Self {
         Self(core::ptr::null_mut())
@@ -1195,13 +1195,13 @@ impl BSTR {
         if value.is_empty() {
             return Self(::core::ptr::null_mut());
         }
-        unsafe { SysAllocStringLen(PWSTR(value.as_ptr() as *mut _), value.len() as u32) }
+        unsafe { SysAllocStringLen(PWSTR(value.as_ptr()), value.len() as u32) }
     }
     pub fn as_wide(&self) -> &[u16] {
         if self.0.is_null() {
             return &[];
         }
-        unsafe { ::core::slice::from_raw_parts(self.0 as *const u16, self.len()) }
+        unsafe { ::core::slice::from_raw_parts(self.0, self.len()) }
     }
 }
 impl ::core::clone::Clone for BSTR {
@@ -1292,7 +1292,6 @@ impl ::core::ops::Drop for BSTR {
 unsafe impl ::windows::core::Abi for BSTR {
     type Abi = ::core::mem::ManuallyDrop<Self>;
 }
-pub type BSTR_abi = *mut u16;
 #[cfg(feature = "alloc")]
 impl<'a> ::windows::core::IntoParam<'a, BSTR> for &str {
     fn into_param(self) -> ::windows::core::Param<'a, BSTR> {
@@ -1410,7 +1409,7 @@ unsafe impl ::windows::core::Abi for HINSTANCE {
     type Abi = Self;
 }
 #[repr(transparent)]
-pub struct PSTR(pub *mut u8);
+pub struct PSTR(pub *const u8);
 impl PSTR {
     pub fn is_null(&self) -> bool {
         self.0.is_null()
@@ -1444,7 +1443,7 @@ unsafe impl ::windows::core::Abi for PSTR {
     unsafe fn drop_param(param: &mut ::windows::core::Param<'_, Self>) {
         if let ::windows::core::Param::Boxed(value) = param {
             if !value.is_null() {
-                ::windows::core::alloc::boxed::Box::from_raw(value.0);
+                ::windows::core::alloc::boxed::Box::from_raw(value.0 as *mut u8);
             }
         }
     }
@@ -1462,7 +1461,7 @@ impl<'a> ::windows::core::IntoParam<'a, PSTR> for ::windows::core::alloc::string
     }
 }
 #[repr(transparent)]
-pub struct PWSTR(pub *mut u16);
+pub struct PWSTR(pub *const u16);
 impl PWSTR {
     pub fn is_null(&self) -> bool {
         self.0.is_null()
@@ -1496,7 +1495,7 @@ unsafe impl ::windows::core::Abi for PWSTR {
     unsafe fn drop_param(param: &mut ::windows::core::Param<'_, Self>) {
         if let ::windows::core::Param::Boxed(value) = param {
             if !value.is_null() {
-                ::windows::core::alloc::boxed::Box::from_raw(value.0);
+                ::windows::core::alloc::boxed::Box::from_raw(value.0 as *mut u16);
             }
         }
     }

crates/samples/create_window/src/main.rs

@@ -10,7 +10,7 @@ fn main() -> Result<()> {
         let wc = WNDCLASSA {
             hCursor: LoadCursorW(None, IDC_ARROW),
             hInstance: instance,
-            lpszClassName: PSTR(b"window\0".as_ptr() as _),
+            lpszClassName: PSTR(b"window\0".as_ptr()),
 
             style: CS_HREDRAW | CS_VREDRAW,
             lpfnWndProc: Some(wndproc),

crates/samples/create_window_sys/src/main.rs

@@ -5,7 +5,7 @@ fn main() {
         let instance = GetModuleHandleA(std::ptr::null_mut());
         debug_assert!(instance != 0);
 
-        let window_class = b"window\0".as_ptr() as _;
+        let window_class = b"window\0".as_ptr();
 
         let wc = WNDCLASSA {
             hCursor: LoadCursorW(0, IDC_ARROW),
@@ -23,7 +23,7 @@ fn main() {
         let atom = RegisterClassA(&wc);
         debug_assert!(atom != 0);
 
-        CreateWindowExA(0, window_class, b"This is a sample window".as_ptr() as _, WS_OVERLAPPEDWINDOW | WS_VISIBLE, CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, 0, 0, instance, std::ptr::null_mut());
+        CreateWindowExA(0, window_class, b"This is a sample window\0".as_ptr(), WS_OVERLAPPEDWINDOW | WS_VISIBLE, CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, 0, 0, instance, std::ptr::null_mut());
 
         let mut message = std::mem::zeroed();
 

crates/samples/direct2d/src/main.rs

@@ -315,7 +315,7 @@ impl Window {
             let wc = WNDCLASSA {
                 hCursor: LoadCursorW(None, IDC_HAND),
                 hInstance: instance,
-                lpszClassName: PSTR(b"window\0".as_ptr() as _),
+                lpszClassName: PSTR(b"window\0".as_ptr()),
 
                 style: CS_HREDRAW | CS_VREDRAW,
                 lpfnWndProc: Some(Self::wndproc),
@@ -325,7 +325,7 @@ impl Window {
             let atom = RegisterClassA(&wc);
             debug_assert!(atom != 0);
 
-            let handle = CreateWindowExA(Default::default(), PSTR(b"window\0".as_ptr() as _), PSTR(b"Sample Window\0".as_ptr() as _), WS_OVERLAPPEDWINDOW | WS_VISIBLE, CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, None, None, instance, self as *mut _ as _);
+            let handle = CreateWindowExA(Default::default(), PSTR(b"window\0".as_ptr()), PSTR(b"Sample Window\0".as_ptr()), WS_OVERLAPPEDWINDOW | WS_VISIBLE, CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, CW_USEDEFAULT, None, None, instance, self as *mut _ as _);
 
             debug_assert!(handle.0 != 0);
             debug_assert!(handle == self.handle);

crates/samples/direct3d12/src/main.rs

@@ -53,7 +53,7 @@ where
         lpfnWndProc: Some(wndproc::<S>),
         hInstance: instance,
         hCursor: unsafe { LoadCursorW(None, IDC_ARROW) },
-        lpszClassName: PSTR(b"RustWindowClass\0".as_ptr() as _),
+        lpszClassName: PSTR(b"RustWindowClass\0".as_ptr()),
         ..Default::default()
     };
 
@@ -459,7 +459,7 @@ mod d3d12_hello_triangle {
 
         let mut input_element_descs: [D3D12_INPUT_ELEMENT_DESC; 2] = [
             D3D12_INPUT_ELEMENT_DESC {
-                SemanticName: PSTR(b"POSITION\0".as_ptr() as _),
+                SemanticName: PSTR(b"POSITION\0".as_ptr()),
                 SemanticIndex: 0,
                 Format: DXGI_FORMAT_R32G32B32_FLOAT,
                 InputSlot: 0,
@@ -468,7 +468,7 @@ mod d3d12_hello_triangle {
                 InstanceDataStepRate: 0,
             },
             D3D12_INPUT_ELEMENT_DESC {
-                SemanticName: PSTR(b"COLOR\0".as_ptr() as _),
+                SemanticName: PSTR(b"COLOR\0".as_ptr()),
                 SemanticIndex: 0,
                 Format: DXGI_FORMAT_R32G32B32A32_FLOAT,
                 InputSlot: 0,