Add VK_KHR_timeline_semaphore extension support (ash-rs#276)

* TimelineSemaphore struct added presenting `VK_KHR_timeline_semaphore` extension.

* Unused import removed.

* Empty newline added.

* TimelineSemaphore extension object now provides functions for work with timeline semaphores.

* Function pointers removed from TimelineSemaphore as no longer needed.
*_khr postfix removed from TimelineSemaphore functions to follow the same code style as in other extensions.

* Tiny code reformatting to fit Rustfmt requirements.

* Another attempt to fit Rustfmt requirements.

ash/src/extensions/khr/mod.rs

@@ -7,6 +7,7 @@ pub use self::push_descriptor::PushDescriptor;
 pub use self::ray_tracing::RayTracing;
 pub use self::surface::Surface;
 pub use self::swapchain::Swapchain;
+pub use self::timeline_semaphore::TimelineSemaphore;
 pub use self::wayland_surface::WaylandSurface;
 pub use self::win32_surface::Win32Surface;
 pub use self::xcb_surface::XcbSurface;
@@ -21,6 +22,7 @@ mod push_descriptor;
 mod ray_tracing;
 mod surface;
 mod swapchain;
+mod timeline_semaphore;
 mod wayland_surface;
 mod win32_surface;
 mod xcb_surface;

ash/src/extensions/khr/timeline_semaphore.rs

@@ -0,0 +1,87 @@
+#![allow(dead_code)]
+use crate::prelude::*;
+use crate::version::{EntryV1_0, InstanceV1_0};
+use crate::vk;
+use std::ffi::CStr;
+use std::mem;
+
+#[derive(Clone)]
+pub struct TimelineSemaphore {
+    handle: vk::Instance,
+    timeline_semaphore_fn: vk::KhrTimelineSemaphoreFn,
+}
+
+impl TimelineSemaphore {
+    pub fn new<E: EntryV1_0, I: InstanceV1_0>(entry: &E, instance: &I) -> TimelineSemaphore {
+        let timeline_semaphore_fn = vk::KhrTimelineSemaphoreFn::load(|name| unsafe {
+            mem::transmute(entry.get_instance_proc_addr(instance.handle(), name.as_ptr()))
+        });
+
+        TimelineSemaphore {
+            handle: instance.handle(),
+            timeline_semaphore_fn,
+        }
+    }
+
+    pub fn name() -> &'static CStr {
+        vk::KhrTimelineSemaphoreFn::name()
+    }
+
+    #[doc = "<https://www.khronos.org/registry/vulkan/specs/1.2-extensions/html/vkspec.html#vkGetSemaphoreCounterValueKHR>"]
+    pub unsafe fn get_semaphore_counter_value(
+        &self,
+        device: vk::Device,
+        semaphore: vk::Semaphore,
+    ) -> VkResult<u64> {
+        let mut value = 0;
+        let err_code = self
+            .timeline_semaphore_fn
+            .get_semaphore_counter_value_khr(device, semaphore, &mut value);
+
+        match err_code {
+            vk::Result::SUCCESS => Ok(value),
+            _ => Err(err_code),
+        }
+    }
+
+    #[doc = "<https://www.khronos.org/registry/vulkan/specs/1.2-extensions/html/vkspec.html#vkWaitSemaphoresKHR>"]
+    pub unsafe fn wait_semaphores(
+        &self,
+        device: vk::Device,
+        wait_info: &vk::SemaphoreWaitInfo,
+        timeout: u64,
+    ) -> VkResult<()> {
+        let err_code = self
+            .timeline_semaphore_fn
+            .wait_semaphores_khr(device, wait_info, timeout);
+
+        match err_code {
+            vk::Result::SUCCESS => Ok(()),
+            _ => Err(err_code),
+        }
+    }
+
+    #[doc = "<https://www.khronos.org/registry/vulkan/specs/1.2-extensions/html/vkspec.html#vkSignalSemaphoreKHR>"]
+    pub unsafe fn signal_semaphore(
+        &self,
+        device: vk::Device,
+        signal_info: &vk::SemaphoreSignalInfo,
+    ) -> VkResult<()> {
+        let err_code = self
+            .timeline_semaphore_fn
+            .signal_semaphore_khr(device, signal_info);
+
+        match err_code {
+            vk::Result::SUCCESS => Ok(()),
+            _ => Err(err_code),
+        }
+    }
+
+    pub fn fp(&self) -> &vk::KhrTimelineSemaphoreFn {
+        &self.timeline_semaphore_fn
+    }
+
+    pub fn instance(&self) -> vk::Instance {
+        self.handle
+    }
+}