mirror of
https://github.com/slint-ui/slint.git
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a1724602e6
Because re-generating the Skia image is slow and there is no point storing both the image buffer and the SkiaImage in the cache as it is basically the same information.
783 lines
31 KiB
Rust
783 lines
31 KiB
Rust
// Copyright © SixtyFPS GmbH <info@slint-ui.com>
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// SPDX-License-Identifier: GPL-3.0-only OR LicenseRef-Slint-commercial
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// cSpell: ignore asyncness constness containee defaultness impls qself supertraits vref
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/*!
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Implementation detail for the vtable crate
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*/
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extern crate proc_macro;
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use proc_macro::TokenStream;
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use quote::quote;
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use syn::parse::Parser;
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use syn::spanned::Spanned;
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use syn::*;
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/// Returns true if the type `ty` is "Container<Containee>"
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fn match_generic_type(ty: &Type, container: &str, containee: &Ident) -> bool {
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if let Type::Path(pat) = ty {
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if let Some(seg) = pat.path.segments.last() {
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if seg.ident != container {
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return false;
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}
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if let PathArguments::AngleBracketed(args) = &seg.arguments {
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if let Some(GenericArgument::Type(Type::Path(arg))) = args.args.last() {
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return Some(containee) == arg.path.get_ident();
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}
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}
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}
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}
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false
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}
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/// Returns Some(type) if the type is `Pin<type>`
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fn is_pin(ty: &Type) -> Option<&Type> {
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if let Type::Path(pat) = ty {
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if let Some(seg) = pat.path.segments.last() {
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if seg.ident != "Pin" {
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return None;
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}
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if let PathArguments::AngleBracketed(args) = &seg.arguments {
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if let Some(GenericArgument::Type(t)) = args.args.last() {
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return Some(t);
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}
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}
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}
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}
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None
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}
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/**
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This macro needs to be applied to a VTable structure
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The design choice is that it is applied to a VTable and not to a trait so that cbindgen
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can see the actual vtable struct.
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This macro needs to be applied to a struct whose name ends with "VTable", and which
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contains members which are function pointers.
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For example, if it is applied to `struct MyTraitVTable`, it will create:
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- The `MyTrait` trait with all the functions.
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- The `MyTraitConsts` trait for the associated constants, if any
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- `MyTraitVTable_static!` macro.
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It will also implement the `VTableMeta` and `VTableMetaDrop` traits so that VRef and so on can work,
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allowing to access methods from the trait directly from VRef.
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This macro does the following transformation:
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For function type fields:
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- The ABI of each functions is changed to `extern "C"`
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- `unsafe` is added to the signature, since it is unsafe to call these functions directly from
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the vtable without having a valid pointer to the actual object. But if the original function was
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marked unsafe, the unsafety is forwarded to the trait.
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- If a field is called `drop`, then it is understood that this is the destructor for a VBox.
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It must have the type `fn(VRefMut<MyVTable>)`
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- If two fields called `drop_in_place` and `dealloc` are present, then they are understood to be
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in-place destructors and deallocation functions. `drop_in_place` must have the signature
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`fn(VRefMut<MyVTable> -> Layout`, and `dealloc` must have the signature
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`fn(&MyVTable, ptr: *mut u8, layout: Layout)`.
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`drop_in_place` is responsible for destructing the object and returning the memory layout that
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was used for the initial allocation. It will be passed to `dealloc`, which is responsible for releasing
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the memory. These two functions are used to enable the use of `VRc` and `VWeak`.
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- If the first argument of the function is `VRef<MyVTable>` or `VRefMut<MyVTable>`, then it is
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understood as a `&self` or `&mut self` argument in the trait.
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- Similarly, if it is a `Pin<VRef<MyVTable>>` or `Pin<VRefMut<MyVTable>>`, self is mapped
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to `Pin<&Self>` or `Pin<&mut Self>`
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For the other fields:
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- They are considered associated constants of the MyTraitConsts trait.
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- If they are annotated with the `#[field_offset(FieldType)]` attribute, the type of the field must be `usize`,
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and the associated const in the trait will be of type `FieldOffset<Self, FieldType>`, and an accessor to
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the field reference and reference mut will be added to the Target of VRef and VRefMut.
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The VRef/VRefMut/VBox structure will dereference to a type which has the following associated items:
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- The functions from the vtable that have a VRef or VRefMut first parameter for self.
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- For each `#[field_offset]` attributes, a corresponding getter returns a reference
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to that field, and mutable accessor that ends with `_mut` returns a mutable reference.
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- `as_ptr` returns a `*mut u8`
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- `get_vtable` Return a reference to the VTable so one can access the associated consts.
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The VTable struct gets a `new` associated function that creates a vtable for any type
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that implements the generated traits.
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## Example
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```
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use vtable::*;
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// we are going to declare a VTable structure for an Animal trait
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#[vtable]
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#[repr(C)]
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struct AnimalVTable {
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/// Pointer to a function that make noise.
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/// `unsafe` and `extern "C"` will automatically be added
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make_noise: fn(VRef<AnimalVTable>, i32) -> i32,
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/// if there is a 'drop' member, it is considered as the destructor
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drop: fn(VRefMut<AnimalVTable>),
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/// Associated constant.
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LEG_NUMBER: i8,
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/// There exist a `bool` field in the structure and this is an offset
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#[field_offset(bool)]
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IS_HUNGRY: usize,
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}
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#[repr(C)]
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struct Dog{ strength: i32, is_hungry: bool };
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// The #[vtable] macro created the Animal Trait
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impl Animal for Dog {
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fn make_noise(&self, intensity: i32) -> i32 {
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println!("Wof!");
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return self.strength * intensity;
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}
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}
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// The #[vtable] macro created the AnimalConsts Trait
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impl AnimalConsts for Dog {
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const LEG_NUMBER: i8 = 4;
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const IS_HUNGRY: vtable::FieldOffset<Self, bool> = unsafe { vtable::FieldOffset::new_from_offset(4) };
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}
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// The #[vtable] macro also exposed a macro to create a vtable
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AnimalVTable_static!(static DOG_VT for Dog);
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// with that, it is possible to instantiate a vtable::VRefMut
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let mut dog = Dog { strength: 100, is_hungry: false };
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{
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let mut animal_vref = VRefMut::<AnimalVTable>::new(&mut dog);
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// access to the vtable through the get_vtable() function
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assert_eq!(animal_vref.get_vtable().LEG_NUMBER, 4);
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// functions are also added for the #[field_offset] member
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assert_eq!(*animal_vref.IS_HUNGRY(), false);
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*animal_vref.IS_HUNGRY_mut() = true;
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}
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assert_eq!(dog.is_hungry, true);
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```
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*/
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#[proc_macro_attribute]
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pub fn vtable(_attr: TokenStream, item: TokenStream) -> TokenStream {
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let mut input = parse_macro_input!(item as ItemStruct);
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let fields = if let Fields::Named(fields) = &mut input.fields {
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fields
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} else {
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return Error::new(
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proc_macro2::Span::call_site(),
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"Only supported for structure with named fields",
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)
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.to_compile_error()
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.into();
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};
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let vtable_name = input.ident.to_string();
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if !vtable_name.ends_with("VTable") {
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return Error::new(input.ident.span(), "The structure does not ends in 'VTable'")
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.to_compile_error()
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.into();
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}
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let trait_name = Ident::new(&vtable_name[..vtable_name.len() - 6], input.ident.span());
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let to_name = quote::format_ident!("{}TO", trait_name);
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let module_name = quote::format_ident!("{}_vtable_mod", trait_name);
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let static_vtable_macro_name = quote::format_ident!("{}_static", vtable_name);
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let vtable_name = input.ident.clone();
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let mut drop_impls = vec![];
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let mut generated_trait = ItemTrait {
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attrs: input
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.attrs
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.iter()
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.filter(|a| a.path.get_ident().as_ref().map(|i| *i == "doc").unwrap_or(false))
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.cloned()
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.collect(),
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vis: Visibility::Public(VisPublic { pub_token: Default::default() }),
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unsafety: None,
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auto_token: None,
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trait_token: Default::default(),
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ident: trait_name.clone(),
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generics: Generics::default(),
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colon_token: None,
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supertraits: Default::default(),
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brace_token: Default::default(),
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items: Default::default(),
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};
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let additional_doc = format!(
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"\nNote: Was generated from the [`#[vtable]`](vtable) macro on [`{}`]",
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vtable_name
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);
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generated_trait
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.attrs
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.append(&mut Attribute::parse_outer.parse2(quote!(#[doc = #additional_doc])).unwrap());
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let mut generated_trait_assoc_const = None;
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let mut generated_to_fn_trait = vec![];
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let mut generated_type_assoc_fn = vec![];
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let mut vtable_ctor = vec![];
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for field in &mut fields.named {
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// The vtable can only be accessed in unsafe code, so it is ok if all its fields are Public
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field.vis = Visibility::Public(VisPublic { pub_token: Default::default() });
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let ident = field.ident.as_ref().unwrap();
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let mut some = None;
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let func_ty = if let Type::BareFn(f) = &mut field.ty {
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Some(f)
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} else if let Type::Path(pat) = &mut field.ty {
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pat.path.segments.last_mut().and_then(|seg| {
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if seg.ident == "Option" {
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some = Some(quote!(Some));
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if let PathArguments::AngleBracketed(args) = &mut seg.arguments {
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if let Some(GenericArgument::Type(Type::BareFn(f))) = args.args.first_mut()
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{
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Some(f)
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} else {
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None
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}
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} else {
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None
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}
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} else {
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None
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}
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})
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} else {
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None
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};
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if let Some(f) = func_ty {
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let mut sig = Signature {
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constness: None,
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asyncness: None,
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unsafety: f.unsafety,
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abi: None,
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fn_token: f.fn_token,
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ident: ident.clone(),
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generics: Default::default(),
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paren_token: f.paren_token,
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inputs: Default::default(),
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variadic: None,
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output: f.output.clone(),
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};
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let mut sig_extern = sig.clone();
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sig_extern.abi = Some(parse_str("extern \"C\"").unwrap());
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sig_extern.generics = parse_str(&format!("<T : {}>", trait_name)).unwrap();
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// check parameters
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let mut call_code = None;
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let mut self_call = None;
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let mut forward_code = None;
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#[derive(Default)]
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struct SelfInfo {}
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let mut has_self = false;
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for param in &f.inputs {
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let arg_name = quote::format_ident!("_{}", sig_extern.inputs.len());
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let typed_arg = FnArg::Typed(PatType {
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attrs: param.attrs.clone(),
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pat: Box::new(Pat::Path(syn::PatPath {
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attrs: Default::default(),
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qself: None,
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path: arg_name.clone().into(),
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})),
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colon_token: Default::default(),
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ty: Box::new(param.ty.clone()),
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});
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sig_extern.inputs.push(typed_arg.clone());
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// check for the vtable
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if let Type::Ptr(TypePtr { mutability, elem, .. })
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| Type::Reference(TypeReference { mutability, elem, .. }) = ¶m.ty
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{
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if let Type::Path(p) = &**elem {
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if let Some(pointer_to) = p.path.get_ident() {
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if pointer_to == &vtable_name {
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if mutability.is_some() {
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return Error::new(p.span(), "VTable cannot be mutable")
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.to_compile_error()
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.into();
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}
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if call_code.is_some() || !sig.inputs.is_empty() {
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return Error::new(
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p.span(),
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"VTable pointer need to be the first",
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)
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.to_compile_error()
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.into();
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}
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call_code = Some(quote!(vtable as _,));
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continue;
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}
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}
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}
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}
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let (is_pin, self_ty) = match is_pin(¶m.ty) {
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Some(t) => (true, t),
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None => (false, ¶m.ty),
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};
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// check for self
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if let (true, mutability) = if match_generic_type(self_ty, "VRef", &vtable_name) {
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(true, None)
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} else if match_generic_type(self_ty, "VRefMut", &vtable_name) {
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(true, Some(Default::default()))
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} else {
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(false, None)
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} {
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if !sig.inputs.is_empty() {
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return Error::new(param.span(), "Self pointer need to be the first")
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.to_compile_error()
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.into();
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}
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let const_or_mut = mutability.map_or_else(|| quote!(const), |x| quote!(#x));
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has_self = true;
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if !is_pin {
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sig.inputs.push(FnArg::Receiver(Receiver {
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attrs: param.attrs.clone(),
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reference: Some(Default::default()),
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mutability,
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self_token: Default::default(),
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}));
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call_code =
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Some(quote!(#call_code <#self_ty>::from_raw(self.vtable, self.ptr),));
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self_call =
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Some(quote!(&#mutability (*(#arg_name.as_ptr() as *#const_or_mut T)),));
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} else {
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// Pinned
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sig.inputs.push(FnArg::Typed(PatType {
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attrs: param.attrs.clone(),
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pat: Box::new(parse2(quote!(self)).unwrap()),
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colon_token: Default::default(),
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ty: parse2(quote!(core::pin::Pin<& #mutability Self>)).unwrap(),
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}));
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call_code = Some(
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quote!(#call_code core::pin::Pin::new_unchecked(<#self_ty>::from_raw(self.vtable, self.ptr)),),
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);
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self_call = Some(
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quote!(core::pin::Pin::new_unchecked(&#mutability (*(#arg_name.as_ptr() as *#const_or_mut T))),),
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);
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}
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continue;
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}
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sig.inputs.push(typed_arg);
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call_code = Some(quote!(#call_code #arg_name,));
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forward_code = Some(quote!(#forward_code #arg_name,));
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}
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// Add unsafe: The function are not safe to call unless the self parameter is of the correct type
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f.unsafety = Some(Default::default());
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// Add extern "C" if it isn't there
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if let Some(a) = &f.abi {
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if !a.name.as_ref().map(|s| s.value() == "C").unwrap_or(false) {
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return Error::new(a.span(), "invalid ABI").to_compile_error().into();
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}
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} else {
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f.abi = sig_extern.abi.clone();
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}
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let mut wrap_trait_call = None;
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if !has_self {
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sig.generics = Generics {
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where_clause: Some(parse_str("where Self : Sized").unwrap()),
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..Default::default()
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};
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// Check if this is a constructor functions
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if let ReturnType::Type(_, ret) = &f.output {
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if match_generic_type(&**ret, "VBox", &vtable_name) {
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// Change VBox<VTable> to Self
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sig.output = parse_str("-> Self").unwrap();
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wrap_trait_call = Some(quote! {
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let wrap_trait_call = |x| unsafe {
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// Put the object on the heap and get a pointer to it
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let ptr = core::ptr::NonNull::from(Box::leak(Box::new(x)));
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VBox::<#vtable_name>::from_raw(vtable, ptr.cast())
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};
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wrap_trait_call
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});
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}
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}
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}
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if ident == "drop" {
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vtable_ctor.push(quote!(#ident: {
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#sig_extern {
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unsafe {
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::core::mem::drop(Box::from_raw((#self_call).0 as *mut _));
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}
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}
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#ident::<T>
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},));
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drop_impls.push(quote! {
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unsafe impl VTableMetaDrop for #vtable_name {
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unsafe fn drop(ptr: *mut #to_name) {
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// Safety: The vtable is valid and inner is a type corresponding to the vtable,
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// which was allocated such that drop is expected.
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unsafe {
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let ptr = &*ptr;
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(ptr.vtable.as_ref().#ident)(VRefMut::from_raw(ptr.vtable, ptr.ptr)) }
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}
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fn new_box<X: HasStaticVTable<#vtable_name>>(value: X) -> VBox<#vtable_name> {
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// Put the object on the heap and get a pointer to it
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let ptr = core::ptr::NonNull::from(Box::leak(Box::new(value)));
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unsafe { VBox::from_raw(core::ptr::NonNull::from(X::static_vtable()), ptr.cast()) }
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}
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}
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});
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continue;
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}
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if ident == "drop_in_place" {
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vtable_ctor.push(quote!(#ident: {
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#[allow(unsafe_code)]
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#sig_extern {
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#[allow(unused_unsafe)]
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unsafe { ::core::ptr::drop_in_place((#self_call).0 as *mut T) };
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::core::alloc::Layout::new::<T>().into()
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}
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#ident::<T>
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},));
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drop_impls.push(quote! {
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#[allow(unsafe_code)]
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unsafe impl VTableMetaDropInPlace for #vtable_name {
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unsafe fn #ident(vtable: &Self::VTable, ptr: *mut u8) -> vtable::Layout {
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// Safety: The vtable is valid and ptr is a type corresponding to the vtable,
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(vtable.#ident)(VRefMut::from_raw(core::ptr::NonNull::from(vtable), core::ptr::NonNull::new_unchecked(ptr).cast()))
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}
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unsafe fn dealloc(vtable: &Self::VTable, ptr: *mut u8, layout: vtable::Layout) {
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(vtable.dealloc)(vtable, ptr, layout)
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}
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}
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});
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continue;
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}
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if ident == "dealloc" {
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vtable_ctor.push(quote!(#ident: {
|
|
#[allow(unsafe_code)]
|
|
unsafe extern "C" fn #ident(_: &#vtable_name, ptr: *mut u8, layout: vtable::Layout) {
|
|
use ::core::convert::TryInto;
|
|
vtable::internal::dealloc(ptr, layout.try_into().unwrap())
|
|
}
|
|
#ident
|
|
},));
|
|
continue;
|
|
}
|
|
|
|
generated_trait.items.push(TraitItem::Method(TraitItemMethod {
|
|
attrs: field.attrs.clone(),
|
|
sig: sig.clone(),
|
|
default: None,
|
|
semi_token: Some(Default::default()),
|
|
}));
|
|
|
|
generated_to_fn_trait.push(ImplItemMethod {
|
|
attrs: field.attrs.clone(),
|
|
vis: Visibility::Public(VisPublic { pub_token: Default::default() }),
|
|
defaultness: None,
|
|
sig: sig.clone(),
|
|
block: parse2(if has_self {
|
|
quote!({
|
|
// Safety: this rely on the vtable being valid, and the ptr being a valid instance for this vtable
|
|
#[allow(unsafe_code)]
|
|
unsafe {
|
|
let vtable = self.vtable.as_ref();
|
|
if let #some(func) = vtable.#ident {
|
|
func (#call_code)
|
|
} else {
|
|
panic!("Called a not-implemented method")
|
|
}
|
|
}
|
|
})
|
|
} else {
|
|
// This should never happen: nobody should be able to access the Trait Object directly.
|
|
quote!({ panic!("Calling Sized method on a Trait Object") })
|
|
})
|
|
.unwrap(),
|
|
});
|
|
|
|
if !has_self {
|
|
sig.inputs.insert(
|
|
0,
|
|
FnArg::Receiver(Receiver {
|
|
attrs: Default::default(),
|
|
reference: Some(Default::default()),
|
|
mutability: None,
|
|
self_token: Default::default(),
|
|
}),
|
|
);
|
|
sig.output = sig_extern.output.clone();
|
|
generated_type_assoc_fn.push(ImplItemMethod {
|
|
attrs: field.attrs.clone(),
|
|
vis: generated_trait.vis.clone(),
|
|
defaultness: None,
|
|
sig,
|
|
block: parse2(quote!({
|
|
let vtable = self;
|
|
// Safety: this rely on the vtable being valid, and the ptr being a valid instance for this vtable
|
|
#[allow(unsafe_code)]
|
|
unsafe { (self.#ident)(#call_code) }
|
|
}))
|
|
.unwrap(),
|
|
});
|
|
|
|
vtable_ctor.push(quote!(#ident: {
|
|
#sig_extern {
|
|
// This is safe since the self must be a instance of our type
|
|
#[allow(unused)]
|
|
#[allow(unsafe_code)]
|
|
let vtable = unsafe { core::ptr::NonNull::from(&*_0) };
|
|
#wrap_trait_call(T::#ident(#self_call #forward_code))
|
|
}
|
|
#some(#ident::<T>)
|
|
},));
|
|
} else {
|
|
let erase_return_type_lifetime = match &sig_extern.output {
|
|
ReturnType::Default => quote!(),
|
|
// If the return type contains a implicit lifetime, it is safe to erase it while returning it
|
|
// because a sound implementation of the trait wouldn't allow unsound things here
|
|
ReturnType::Type(_, r) => quote!(core::mem::transmute::<#r, #r>),
|
|
};
|
|
vtable_ctor.push(quote!(#ident: {
|
|
#sig_extern {
|
|
// This is safe since the self must be a instance of our type
|
|
#[allow(unsafe_code)]
|
|
unsafe { #erase_return_type_lifetime(T::#ident(#self_call #forward_code)) }
|
|
}
|
|
#ident::<T>
|
|
},));
|
|
}
|
|
} else {
|
|
// associated constant
|
|
|
|
let generated_trait_assoc_const =
|
|
generated_trait_assoc_const.get_or_insert_with(|| ItemTrait {
|
|
attrs: Attribute::parse_outer.parse_str(&format!(
|
|
"/** Trait containing the associated constant relative to the trait {}.\n{} */",
|
|
trait_name, additional_doc
|
|
)).unwrap(),
|
|
ident: quote::format_ident!("{}Consts", trait_name),
|
|
items: vec![],
|
|
..generated_trait.clone()
|
|
});
|
|
|
|
let const_type = if let Some(o) = field
|
|
.attrs
|
|
.iter()
|
|
.position(|a| a.path.get_ident().map(|a| a == "field_offset").unwrap_or(false))
|
|
{
|
|
let a = field.attrs.remove(o);
|
|
let member_type = match parse2::<Type>(a.tokens) {
|
|
Err(e) => return e.to_compile_error().into(),
|
|
Ok(ty) => ty,
|
|
};
|
|
|
|
match &field.ty {
|
|
Type::Path(p) if p.path.get_ident().map(|i| i == "usize").unwrap_or(false) => {}
|
|
ty => {
|
|
return Error::new(
|
|
ty.span(),
|
|
"The type of an #[field_offset] member in the vtable must be 'usize'",
|
|
)
|
|
.to_compile_error()
|
|
.into()
|
|
}
|
|
}
|
|
|
|
// add `: Sized` to the trait in case it does not have it
|
|
if generated_trait_assoc_const.supertraits.is_empty() {
|
|
generated_trait_assoc_const.colon_token = Some(Default::default());
|
|
generated_trait_assoc_const.supertraits.push(parse2(quote!(Sized)).unwrap());
|
|
}
|
|
|
|
let offset_type =
|
|
parse2::<Type>(quote!(vtable::FieldOffset<Self, #member_type>)).unwrap();
|
|
|
|
vtable_ctor.push(quote!(#ident: T::#ident.get_byte_offset(),));
|
|
|
|
let attrs = &field.attrs;
|
|
|
|
let vis = &field.vis;
|
|
generated_to_fn_trait.push(
|
|
parse2(quote! {
|
|
#(#attrs)*
|
|
#vis fn #ident(&self) -> &#member_type {
|
|
unsafe {
|
|
&*(self.ptr.as_ptr().add(self.vtable.as_ref().#ident) as *const #member_type)
|
|
}
|
|
}
|
|
})
|
|
.unwrap(),
|
|
);
|
|
let ident_mut = quote::format_ident!("{}_mut", ident);
|
|
generated_to_fn_trait.push(
|
|
parse2(quote! {
|
|
#(#attrs)*
|
|
#vis fn #ident_mut(&mut self) -> &mut #member_type {
|
|
unsafe {
|
|
&mut *(self.ptr.as_ptr().add(self.vtable.as_ref().#ident) as *mut #member_type)
|
|
}
|
|
}
|
|
})
|
|
.unwrap(),
|
|
);
|
|
|
|
offset_type
|
|
} else {
|
|
vtable_ctor.push(quote!(#ident: T::#ident,));
|
|
field.ty.clone()
|
|
};
|
|
|
|
generated_trait_assoc_const.items.push(TraitItem::Const(TraitItemConst {
|
|
attrs: field.attrs.clone(),
|
|
const_token: Default::default(),
|
|
ident: ident.clone(),
|
|
colon_token: Default::default(),
|
|
ty: const_type,
|
|
default: None,
|
|
semi_token: Default::default(),
|
|
}));
|
|
};
|
|
}
|
|
|
|
let vis = input.vis;
|
|
input.vis = Visibility::Public(VisPublic { pub_token: Default::default() });
|
|
|
|
let new_trait_extra = generated_trait_assoc_const.as_ref().map(|x| {
|
|
let i = &x.ident;
|
|
quote!(+ #i)
|
|
});
|
|
|
|
let static_vtable_macro_doc = format!(
|
|
r"Instantiate a static {vtable} for a given type and implements `vtable::HasStaticVTable<{vtable}>` for it.
|
|
|
|
```ignore
|
|
// The preview above is misleading because of rust-lang/rust#45939, so it is reproduced below
|
|
macro_rules! {macro} {{
|
|
($(#[$meta:meta])* $vis:vis static $ident:ident for $ty:ty) => {{ ... }}
|
|
}}
|
|
```
|
|
|
|
Given a type `MyType` that implements the trait `{trait} {trait_extra}`,
|
|
create a static variable of type {vtable},
|
|
and implements HasStaticVTable for it.
|
|
|
|
```ignore
|
|
struct Foo {{ ... }}
|
|
impl {trait} for Foo {{ ... }}
|
|
{macro}!(static FOO_VTABLE for Foo);
|
|
// now VBox::new can be called
|
|
let vbox = VBox::new(Foo{{ ... }});
|
|
```
|
|
|
|
{extra}",
|
|
vtable = vtable_name,
|
|
trait = trait_name,
|
|
trait_extra = new_trait_extra.as_ref().map(|x| x.to_string()).unwrap_or_default(),
|
|
macro = static_vtable_macro_name,
|
|
extra = additional_doc,
|
|
);
|
|
|
|
let result = quote!(
|
|
#[allow(non_snake_case)]
|
|
#[macro_use]
|
|
/// This private module is generated by the `vtable` macro
|
|
mod #module_name {
|
|
#![allow(unused_parens)]
|
|
#[allow(unused)]
|
|
use super::*;
|
|
use ::vtable::*;
|
|
use ::vtable::internal::*;
|
|
#input
|
|
|
|
impl #vtable_name {
|
|
// unfortunately cannot be const in stable rust because of the bounds (depends on rfc 2632)
|
|
/// Create a vtable suitable for a given type implementing the trait.
|
|
pub /*const*/ fn new<T: #trait_name #new_trait_extra>() -> Self {
|
|
Self {
|
|
#(#vtable_ctor)*
|
|
}
|
|
}
|
|
#(#generated_type_assoc_fn)*
|
|
}
|
|
|
|
#generated_trait
|
|
#generated_trait_assoc_const
|
|
|
|
/// Invariant, same as vtable::Inner: vtable and ptr has to be valid and ptr an instance matching the vtable
|
|
#[doc(hidden)]
|
|
#[repr(C)]
|
|
pub struct #to_name {
|
|
vtable: core::ptr::NonNull<#vtable_name>,
|
|
ptr: core::ptr::NonNull<u8>,
|
|
}
|
|
impl #to_name {
|
|
#(#generated_to_fn_trait)*
|
|
|
|
/// Returns a reference to the VTable
|
|
pub fn get_vtable(&self) -> &#vtable_name {
|
|
unsafe { self.vtable.as_ref() }
|
|
}
|
|
|
|
/// Return a raw pointer to the object
|
|
pub fn as_ptr(&self) -> *const u8 {
|
|
self.ptr.as_ptr()
|
|
}
|
|
}
|
|
|
|
unsafe impl VTableMeta for #vtable_name {
|
|
type VTable = #vtable_name;
|
|
type Target = #to_name;
|
|
}
|
|
|
|
#(#drop_impls)*
|
|
}
|
|
#[doc(inline)]
|
|
#[macro_use]
|
|
#vis use #module_name::*;
|
|
|
|
#[macro_export]
|
|
#[doc = #static_vtable_macro_doc]
|
|
macro_rules! #static_vtable_macro_name {
|
|
($(#[$meta:meta])* $vis:vis static $ident:ident for $ty:ty) => {
|
|
$(#[$meta])* $vis static $ident : #vtable_name = {
|
|
use vtable::*;
|
|
type T = $ty;
|
|
#vtable_name {
|
|
#(#vtable_ctor)*
|
|
}
|
|
};
|
|
#[allow(unsafe_code)]
|
|
unsafe impl vtable::HasStaticVTable<#vtable_name> for $ty {
|
|
fn static_vtable() -> &'static #vtable_name {
|
|
&$ident
|
|
}
|
|
}
|
|
}
|
|
}
|
|
);
|
|
//println!("{}", result);
|
|
result.into()
|
|
}
|