ash-window: Make enumerate_required_extensions return `&[*const c_c…

…har]` (#590)

* Constify generated extension names

* Constify hand-written extension names

* Make ash-window list extensions as &[*const c_char]

This alters enumerate_required_extensions() to return the same type that
is expected by vk::InstanceCreateInfoBuilder::enabled_extension_names(),
allowing simple Vulkan apps to omit the boilerplate of mapping to an
intermediate Vec<*const c_char>.

Co-authored-by: Steve Wooster <s.f.m.wooster@gmail.com>

Changelog.md

@@ -11,6 +11,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Update Vulkan-Headers to 1.3.208 (#597)
 - Added `VK_EXT_headless_surface` instance extension (#589)
 
+### Changed
+
+- Constified extension names (#590)
+
 ## [0.36.0] - 2022-02-21
 
 ### Changed

ash-window/Changelog.md

@@ -2,6 +2,8 @@
 
 ## [Unreleased] - ReleaseDate
 
+- Make `enumerate_required_extensions()` return `&[*const c_char]` instead of `Vec<&CStr>` to match `ash::vk::InstanceCreateInfo` (#590)
+
 ## [0.9.1] - 2022-02-21
 
 ### Changed

ash-window/examples/winit.rs

@@ -17,14 +17,10 @@ fn main() -> Result<(), Box<dyn Error>> {
     unsafe {
         let entry = ash::Entry::linked();
         let surface_extensions = ash_window::enumerate_required_extensions(&window)?;
-        let instance_extensions = surface_extensions
-            .iter()
-            .map(|ext| ext.as_ptr())
-            .collect::<Vec<_>>();
         let app_desc = vk::ApplicationInfo::builder().api_version(vk::make_api_version(0, 1, 0, 0));
         let instance_desc = vk::InstanceCreateInfo::builder()
             .application_info(&app_desc)
-            .enabled_extension_names(&instance_extensions);
+            .enabled_extension_names(surface_extensions);
 
         let instance = entry.create_instance(&instance_desc, None)?;
 

ash-window/src/lib.rs

@@ -1,8 +1,9 @@
 #![warn(trivial_casts, trivial_numeric_casts)]
 
+use std::os::raw::c_char;
+
 use ash::{extensions::khr, prelude::*, vk, Entry, Instance};
 use raw_window_handle::{HasRawWindowHandle, RawWindowHandle};
-use std::ffi::CStr;
 
 #[cfg(any(target_os = "macos", target_os = "ios"))]
 use ash::extensions::ext; // portability extensions
@@ -122,10 +123,16 @@ pub unsafe fn create_surface(
 /// The returned extensions will include all extension dependencies.
 pub fn enumerate_required_extensions(
     window_handle: &dyn HasRawWindowHandle,
-) -> VkResult<Vec<&'static CStr>> {
+) -> VkResult<&'static [*const c_char]> {
     let extensions = match window_handle.raw_window_handle() {
         #[cfg(target_os = "windows")]
-        RawWindowHandle::Windows(_) => vec![khr::Surface::name(), khr::Win32Surface::name()],
+        RawWindowHandle::Windows(_) => {
+            const WINDOWS_EXTS: [*const c_char; 2] = [
+                khr::Surface::name().as_ptr(),
+                khr::Win32Surface::name().as_ptr(),
+            ];
+            &WINDOWS_EXTS
+        }
 
         #[cfg(any(
             target_os = "linux",
@@ -134,7 +141,13 @@ pub fn enumerate_required_extensions(
             target_os = "netbsd",
             target_os = "openbsd"
         ))]
-        RawWindowHandle::Wayland(_) => vec![khr::Surface::name(), khr::WaylandSurface::name()],
+        RawWindowHandle::Wayland(_) => {
+            const WAYLAND_EXTS: [*const c_char; 2] = [
+                khr::Surface::name().as_ptr(),
+                khr::WaylandSurface::name().as_ptr(),
+            ];
+            &WAYLAND_EXTS
+        }
 
         #[cfg(any(
             target_os = "linux",
@@ -143,7 +156,13 @@ pub fn enumerate_required_extensions(
             target_os = "netbsd",
             target_os = "openbsd"
         ))]
-        RawWindowHandle::Xlib(_) => vec![khr::Surface::name(), khr::XlibSurface::name()],
+        RawWindowHandle::Xlib(_) => {
+            const XLIB_EXTS: [*const c_char; 2] = [
+                khr::Surface::name().as_ptr(),
+                khr::XlibSurface::name().as_ptr(),
+            ];
+            &XLIB_EXTS
+        }
 
         #[cfg(any(
             target_os = "linux",
@@ -152,16 +171,40 @@ pub fn enumerate_required_extensions(
             target_os = "netbsd",
             target_os = "openbsd"
         ))]
-        RawWindowHandle::Xcb(_) => vec![khr::Surface::name(), khr::XcbSurface::name()],
+        RawWindowHandle::Xcb(_) => {
+            const XCB_EXTS: [*const c_char; 2] = [
+                khr::Surface::name().as_ptr(),
+                khr::XcbSurface::name().as_ptr(),
+            ];
+            &XCB_EXTS
+        }
 
         #[cfg(any(target_os = "android"))]
-        RawWindowHandle::Android(_) => vec![khr::Surface::name(), khr::AndroidSurface::name()],
+        RawWindowHandle::Android(_) => {
+            const ANDROID_EXTS: [*const c_char; 2] = [
+                khr::Surface::name().as_ptr(),
+                khr::AndroidSurface::name().as_ptr(),
+            ];
+            &ANDROID_EXTS
+        }
 
         #[cfg(any(target_os = "macos"))]
-        RawWindowHandle::MacOS(_) => vec![khr::Surface::name(), ext::MetalSurface::name()],
+        RawWindowHandle::MacOS(_) => {
+            const MACOS_EXTS: [*const c_char; 2] = [
+                khr::Surface::name().as_ptr(),
+                ext::MetalSurface::name().as_ptr(),
+            ];
+            &MACOS_EXTS
+        }
 
         #[cfg(any(target_os = "ios"))]
-        RawWindowHandle::IOS(_) => vec![khr::Surface::name(), ext::MetalSurface::name()],
+        RawWindowHandle::IOS(_) => {
+            const IOS_EXTS: [*const c_char; 2] = [
+                khr::Surface::name().as_ptr(),
+                ext::MetalSurface::name().as_ptr(),
+            ];
+            &IOS_EXTS
+        }
 
         _ => return Err(vk::Result::ERROR_EXTENSION_NOT_PRESENT),
     };

ash/src/extensions/ext/buffer_device_address.rs

@@ -26,7 +26,7 @@ impl BufferDeviceAddress {
         self.fp.get_buffer_device_address_ext(self.handle, info)
     }
 
-    pub fn name() -> &'static CStr {
+    pub const fn name() -> &'static CStr {
         vk::ExtBufferDeviceAddressFn::name()
     }
 

ash/src/extensions/ext/calibrated_timestamps.rs

@@ -51,7 +51,7 @@ impl CalibratedTimestamps {
             .result_with_success((timestamps, max_deviation))
     }
 
-    pub fn name() -> &'static CStr {
+    pub const fn name() -> &'static CStr {
         vk::ExtCalibratedTimestampsFn::name()
     }
 

ash/src/extensions/ext/debug_marker.rs

@@ -54,7 +54,7 @@ impl DebugMarker {
             .cmd_debug_marker_insert_ext(command_buffer, marker_info);
     }
 
-    pub fn name() -> &'static CStr {
+    pub const fn name() -> &'static CStr {
         vk::ExtDebugMarkerFn::name()
     }
 

ash/src/extensions/ext/debug_report.rs

@@ -50,7 +50,7 @@ impl DebugReport {
             .result_with_success(debug_cb)
     }
 
-    pub fn name() -> &'static CStr {
+    pub const fn name() -> &'static CStr {
         vk::ExtDebugReportFn::name()
     }
 

ash/src/extensions/ext/debug_utils.rs

@@ -131,7 +131,7 @@ impl DebugUtils {
         );
     }
 
-    pub fn name() -> &'static CStr {
+    pub const fn name() -> &'static CStr {
         vk::ExtDebugUtilsFn::name()
     }
 

ash/src/extensions/ext/extended_dynamic_state.rs

@@ -175,7 +175,7 @@ impl ExtendedDynamicState {
         )
     }
 
-    pub fn name() -> &'static CStr {
+    pub const fn name() -> &'static CStr {
         vk::ExtExtendedDynamicStateFn::name()
     }
 

ash/src/extensions/ext/extended_dynamic_state2.rs

@@ -66,7 +66,7 @@ impl ExtendedDynamicState2 {
             .cmd_set_primitive_restart_enable_ext(command_buffer, primitive_restart_enable.into())
     }
 
-    pub fn name() -> &'static CStr {
+    pub const fn name() -> &'static CStr {
         vk::ExtExtendedDynamicState2Fn::name()
     }
 

ash/src/extensions/ext/full_screen_exclusive.rs

@@ -70,7 +70,7 @@ impl FullScreenExclusive {
             .result_with_success(present_modes)
     }
 
-    pub fn name() -> &'static CStr {
+    pub const fn name() -> &'static CStr {
         vk::ExtFullScreenExclusiveFn::name()
     }
 

ash/src/extensions/ext/headless_surface.rs

@@ -38,7 +38,7 @@ impl HeadlessSurface {
             .result_with_success(surface)
     }
 
-    pub fn name() -> &'static CStr {
+    pub const fn name() -> &'static CStr {
         vk::ExtHeadlessSurfaceFn::name()
     }
 

ash/src/extensions/ext/metal_surface.rs

@@ -37,7 +37,7 @@ impl MetalSurface {
             .result_with_success(surface)
     }
 
-    pub fn name() -> &'static CStr {
+    pub const fn name() -> &'static CStr {
         vk::ExtMetalSurfaceFn::name()
     }
 

ash/src/extensions/ext/physical_device_drm.rs

@@ -18,7 +18,7 @@ impl PhysicalDeviceDrm {
         props_drm
     }
 
-    pub fn name() -> &'static CStr {
+    pub const fn name() -> &'static CStr {
         vk::ExtPhysicalDeviceDrmFn::name()
     }
 }

ash/src/extensions/ext/private_data.rs

@@ -86,7 +86,7 @@ impl PrivateData {
         data
     }
 
-    pub fn name() -> &'static CStr {
+    pub const fn name() -> &'static CStr {
         vk::ExtPrivateDataFn::name()
     }
 

ash/src/extensions/ext/tooling_info.rs

@@ -28,7 +28,7 @@ impl ToolingInfo {
         })
     }
 
-    pub fn name() -> &'static CStr {
+    pub const fn name() -> &'static CStr {
         vk::ExtToolingInfoFn::name()
     }
 

ash/src/extensions/khr/acceleration_structure.rs

@@ -299,7 +299,7 @@ impl AccelerationStructure {
         size_info
     }
 
-    pub fn name() -> &'static CStr {
+    pub const fn name() -> &'static CStr {
         vk::KhrAccelerationStructureFn::name()
     }
 

ash/src/extensions/khr/android_surface.rs

@@ -37,7 +37,7 @@ impl AndroidSurface {
             .result_with_success(surface)
     }
 
-    pub fn name() -> &'static CStr {
+    pub const fn name() -> &'static CStr {
         vk::KhrAndroidSurfaceFn::name()
     }
 

ash/src/extensions/khr/buffer_device_address.rs

@@ -44,7 +44,7 @@ impl BufferDeviceAddress {
             .get_device_memory_opaque_capture_address_khr(self.handle, info)
     }
 
-    pub fn name() -> &'static CStr {
+    pub const fn name() -> &'static CStr {
         vk::KhrBufferDeviceAddressFn::name()
     }
 

ash/src/extensions/khr/copy_commands2.rs

@@ -70,7 +70,7 @@ impl CopyCommands2 {
             .cmd_resolve_image2_khr(command_buffer, resolve_image_info)
     }
 
-    pub fn name() -> &'static CStr {
+    pub const fn name() -> &'static CStr {
         vk::KhrCopyCommands2Fn::name()
     }
 

ash/src/extensions/khr/create_render_pass2.rs

@@ -72,7 +72,7 @@ impl CreateRenderPass2 {
             .cmd_end_render_pass2_khr(command_buffer, subpass_end_info);
     }
 
-    pub fn name() -> &'static CStr {
+    pub const fn name() -> &'static CStr {
         vk::KhrCreateRenderpass2Fn::name()
     }
 

ash/src/extensions/khr/deferred_host_operations.rs

@@ -77,7 +77,7 @@ impl DeferredHostOperations {
             .result()
     }
 
-    pub fn name() -> &'static CStr {
+    pub const fn name() -> &'static CStr {
         vk::KhrDeferredHostOperationsFn::name()
     }
 

ash/src/extensions/khr/display.rs

@@ -125,7 +125,7 @@ impl Display {
             .result_with_success(surface.assume_init())
     }
 
-    pub fn name() -> &'static CStr {
+    pub const fn name() -> &'static CStr {
         vk::KhrDisplayFn::name()
     }
 

ash/src/extensions/khr/display_swapchain.rs

@@ -38,7 +38,7 @@ impl DisplaySwapchain {
         err_code.result_with_success(swapchains)
     }
 
-    pub fn name() -> &'static CStr {
+    pub const fn name() -> &'static CStr {
         vk::KhrDisplaySwapchainFn::name()
     }
 

ash/src/extensions/khr/draw_indirect_count.rs

@@ -60,7 +60,7 @@ impl DrawIndirectCount {
         );
     }
 
-    pub fn name() -> &'static CStr {
+    pub const fn name() -> &'static CStr {
         vk::KhrDrawIndirectCountFn::name()
     }
 

ash/src/extensions/khr/dynamic_rendering.rs

@@ -31,7 +31,7 @@ impl DynamicRendering {
         self.fp.cmd_end_rendering_khr(command_buffer)
     }
 
-    pub fn name() -> &'static CStr {
+    pub const fn name() -> &'static CStr {
         vk::KhrDynamicRenderingFn::name()
     }
 

ash/src/extensions/khr/external_fence_fd.rs

@@ -34,7 +34,7 @@ impl ExternalFenceFd {
             .result_with_success(fd)
     }
 
-    pub fn name() -> &'static CStr {
+    pub const fn name() -> &'static CStr {
         vk::KhrExternalFenceFdFn::name()
     }
 

ash/src/extensions/khr/external_fence_win32.rs

@@ -42,7 +42,7 @@ impl ExternalFenceWin32 {
             .result_with_success(handle)
     }
 
-    pub fn name() -> &'static CStr {
+    pub const fn name() -> &'static CStr {
         vk::KhrExternalFenceWin32Fn::name()
     }
 

ash/src/extensions/khr/external_memory_fd.rs

@@ -39,7 +39,7 @@ impl ExternalMemoryFd {
             .result_with_success(memory_fd_properties)
     }
 
-    pub fn name() -> &'static CStr {
+    pub const fn name() -> &'static CStr {
         vk::KhrExternalMemoryFdFn::name()
     }
 

ash/src/extensions/khr/external_memory_win32.rs

@@ -49,7 +49,7 @@ impl ExternalMemoryWin32 {
             .result_with_success(memory_win32_handle_properties)
     }
 
-    pub fn name() -> &'static CStr {
+    pub const fn name() -> &'static CStr {
         vk::KhrExternalMemoryWin32Fn::name()
     }
 

ash/src/extensions/khr/external_semaphore_fd.rs

@@ -37,7 +37,7 @@ impl ExternalSemaphoreFd {
             .result_with_success(fd)
     }
 
-    pub fn name() -> &'static CStr {
+    pub const fn name() -> &'static CStr {
         vk::KhrExternalSemaphoreFdFn::name()
     }