项目地址：github.com/gfx-rs/meta…

Rust 表达 Objective-C new操作

pub enum MTLHeapDescriptor {}foreign_obj_type! {type CType = MTLHeapDescriptor;pub struct HeapDescriptor;pub struct HeapDescriptorRef;
}impl HeapDescriptor {pub fn new() -> Self {unsafe {let class = class!(MTLHeapDescriptor);msg_send![class, new]}}
}impl HeapDescriptorRef {pub fn cpu_cache_mode(&self) -> MTLCPUCacheMode {unsafe { msg_send![self, cpuCacheMode] }}pub fn set_cpu_cache_mode(&self, mode: MTLCPUCacheMode) {unsafe { msg_send![self, setCpuCacheMode: mode] }}pub fn storage_mode(&self) -> MTLStorageMode {unsafe { msg_send![self, storageMode] }}pub fn set_storage_mode(&self, mode: MTLStorageMode) {unsafe { msg_send![self, setStorageMode: mode] }}pub fn size(&self) -> NSUInteger {unsafe { msg_send![self, size] }}pub fn set_size(&self, size: NSUInteger) {unsafe {msg_send![self, setSize: size];}}
}
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Rust 表达 Objective-C 继承关系

父类CAMetalDrawable继承自NSObject，用Rust表达如下。

pub enum MTLDrawable {}foreign_obj_type! {type CType = MTLDrawable;pub struct Drawable;pub struct DrawableRef;
}impl DrawableRef {pub fn present(&self) {unsafe {msg_send![self, present]}}
}
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子类CAMetalDrawable用Rust表达如下。

pub enum CAMetalDrawable {}foreign_obj_type! {type CType = CAMetalDrawable;pub struct CoreAnimationDrawable;pub struct CoreAnimationDrawableRef;type ParentType = DrawableRef;
}impl CoreAnimationDrawableRef {pub fn texture(&self) -> &TextureRef {unsafe { msg_send![self, texture] }}
}
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工具宏

macro_rules! foreign_obj_type {{type CType = $raw_ident:ident;pub struct $owned_ident:ident;pub struct $ref_ident:ident;type ParentType = $parent_ref:ident;} => {foreign_obj_type! {type CType = $raw_ident;pub struct $owned_ident;pub struct $ref_ident;}impl ::std::ops::Deref for $ref_ident {type Target = $parent_ref;fn deref(&self) -> &$parent_ref {unsafe { &*(self as *const $ref_ident as *const $parent_ref)  }}}};{type CType = $raw_ident:ident;pub struct $owned_ident:ident;pub struct $ref_ident:ident;} => {foreign_type! {type CType = $raw_ident;fn drop = ::obj_drop;fn clone = ::obj_clone;pub struct $owned_ident;pub struct $ref_ident;}unsafe impl ::objc::Message for $raw_ident {}unsafe impl ::objc::Message for $ref_ident {}impl ::std::fmt::Debug for $ref_ident {fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {unsafe {use ::objc_foundation::INSString;// TODO: might leak, not 100% sure...let string: &::objc_foundation::NSString = msg_send![self, debugDescription];write!(f, "{}", string.as_str())}}}impl ::std::fmt::Debug for $owned_ident {fn fmt(&self, f: &mut ::std::fmt::Formatter) -> ::std::fmt::Result {::std::ops::Deref::deref(self).fmt(f)}}};
}
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辅助项目

上述操作依赖如下项目：

• foreign-types
• rust-objc