1 files changed, 116 insertions, 0 deletions
diff --git a/third_party/rust/wgpu-core/src/hal_api.rs b/third_party/rust/wgpu-core/src/hal_api.rs
new file mode 100644
index 0000000000..179024baed
--- /dev/null
+++ b/third_party/rust/wgpu-core/src/hal_api.rs
@@ -0,0 +1,116 @@
+use wgt::{Backend, WasmNotSendSync};
+
+use crate::{
+    global::Global,
+    hub::Hub,
+    instance::{Instance, Surface},
+};
+
+pub trait HalApi: hal::Api + 'static + WasmNotSendSync {
+    const VARIANT: Backend;
+    fn create_instance_from_hal(name: &str, hal_instance: Self::Instance) -> Instance;
+    fn instance_as_hal(instance: &Instance) -> Option<&Self::Instance>;
+    fn hub(global: &Global) -> &Hub<Self>;
+    fn get_surface(surface: &Surface) -> Option<&Self::Surface>;
+}
+
+impl HalApi for hal::api::Empty {
+    const VARIANT: Backend = Backend::Empty;
+    fn create_instance_from_hal(_: &str, _: Self::Instance) -> Instance {
+        unimplemented!("called empty api")
+    }
+    fn instance_as_hal(_: &Instance) -> Option<&Self::Instance> {
+        unimplemented!("called empty api")
+    }
+    fn hub(_: &Global) -> &Hub<Self> {
+        unimplemented!("called empty api")
+    }
+    fn get_surface(_: &Surface) -> Option<&Self::Surface> {
+        unimplemented!("called empty api")
+    }
+}
+
+#[cfg(vulkan)]
+impl HalApi for hal::api::Vulkan {
+    const VARIANT: Backend = Backend::Vulkan;
+    fn create_instance_from_hal(name: &str, hal_instance: Self::Instance) -> Instance {
+        Instance {
+            name: name.to_owned(),
+            vulkan: Some(hal_instance),
+            ..Default::default()
+        }
+    }
+    fn instance_as_hal(instance: &Instance) -> Option<&Self::Instance> {
+        instance.vulkan.as_ref()
+    }
+    fn hub(global: &Global) -> &Hub<Self> {
+        &global.hubs.vulkan
+    }
+    fn get_surface(surface: &Surface) -> Option<&Self::Surface> {
+        surface.raw.downcast_ref::<Self>()
+    }
+}
+
+#[cfg(metal)]
+impl HalApi for hal::api::Metal {
+    const VARIANT: Backend = Backend::Metal;
+    fn create_instance_from_hal(name: &str, hal_instance: Self::Instance) -> Instance {
+        Instance {
+            name: name.to_owned(),
+            metal: Some(hal_instance),
+            ..Default::default()
+        }
+    }
+    fn instance_as_hal(instance: &Instance) -> Option<&Self::Instance> {
+        instance.metal.as_ref()
+    }
+    fn hub(global: &Global) -> &Hub<Self> {
+        &global.hubs.metal
+    }
+    fn get_surface(surface: &Surface) -> Option<&Self::Surface> {
+        surface.raw.downcast_ref::<Self>()
+    }
+}
+
+#[cfg(dx12)]
+impl HalApi for hal::api::Dx12 {
+    const VARIANT: Backend = Backend::Dx12;
+    fn create_instance_from_hal(name: &str, hal_instance: Self::Instance) -> Instance {
+        Instance {
+            name: name.to_owned(),
+            dx12: Some(hal_instance),
+            ..Default::default()
+        }
+    }
+    fn instance_as_hal(instance: &Instance) -> Option<&Self::Instance> {
+        instance.dx12.as_ref()
+    }
+    fn hub(global: &Global) -> &Hub<Self> {
+        &global.hubs.dx12
+    }
+    fn get_surface(surface: &Surface) -> Option<&Self::Surface> {
+        surface.raw.downcast_ref::<Self>()
+    }
+}
+
+#[cfg(gles)]
+impl HalApi for hal::api::Gles {
+    const VARIANT: Backend = Backend::Gl;
+    fn create_instance_from_hal(name: &str, hal_instance: Self::Instance) -> Instance {
+        #[allow(clippy::needless_update)]
+        Instance {
+            name: name.to_owned(),
+            gl: Some(hal_instance),
+            ..Default::default()
+        }
+    }
+    fn instance_as_hal(instance: &Instance) -> Option<&Self::Instance> {
+        instance.gl.as_ref()
+    }
+    fn hub(global: &Global) -> &Hub<Self> {
+        &global.hubs.gl
+    }
+    fn get_surface(surface: &Surface) -> Option<&Self::Surface> {
+        surface.raw.downcast_ref::<Self>()
+    }
+}