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extern crate proc_macro;
use proc_macro::TokenStream;
use proc_macro2::Span;
use quote::{format_ident, quote};
use syn::{
self, parse_macro_input, Data, DeriveInput, Fields, FieldsNamed, FieldsUnnamed, GenericParam,
LitInt, TypeParamBound,
};
#[proc_macro_derive(ViewGroup)]
pub fn derive_viewgroup(input: TokenStream) -> TokenStream {
let ast = parse_macro_input!(input as DeriveInput);
let empty_vg_instance = quote!(unsafe { &embedded_layout::view_group::EMPTY_VIEW_GROUP });
let empty_vg_instance_mut =
quote!(unsafe { &mut embedded_layout::view_group::EMPTY_VIEW_GROUP });
let (
field_count_impl,
index_impl,
index_mut_impl,
translate_impl,
draw_impl,
bounds_of_impl,
translate_child_impl,
) = match &ast.data {
Data::Struct(struct_data) if matches!(&struct_data.fields, Fields::Named(_)) => {
let fields = if let Fields::Named(fields) = &struct_data.fields {
fields
} else {
panic!("Programming error: matches! should have prevent from taking this arm");
};
let field_names = fields
.named
.iter()
.map(|f| f.ident.clone().unwrap())
.collect::<Vec<_>>();
let field_count = format!("{}", field_names.len());
let field_count = LitInt::new(&field_count, Span::call_site());
let translate = field_names
.iter()
.map(|f| quote!(#f: self.#f.clone().translate(by),))
.collect::<Vec<_>>();
let draw = field_names
.iter()
.map(|f| quote!(self.#f.draw(display)?;))
.collect::<Vec<_>>();
let index = field_names
.iter()
.enumerate()
.map(|(i, f)| quote!(#i => &self.#f,))
.collect::<Vec<_>>();
let index_mut = field_names
.iter()
.enumerate()
.map(|(i, f)| quote!(#i => &mut self.#f,))
.collect::<Vec<_>>();
let bounds_of = field_names
.iter()
.enumerate()
.map(|(i, f)| quote!(#i => self.#f.bounds(),))
.collect::<Vec<_>>();
let translate_child = field_names
.iter()
.enumerate()
.map(|(i, f)| quote!(#i => self.#f.translate_impl(by),))
.collect::<Vec<_>>();
let field_count_impl = quote! {
#field_count
};
let index_impl = quote! {
match index {
#(#index)*
_ => #empty_vg_instance
}
};
let index_mut_impl = quote! {
match index {
#(#index_mut)*
_ => #empty_vg_instance_mut
}
};
let translate_impl = quote! {
Self {
#(#translate)*
}
};
let bounds_of_impl = quote! {
match index {
#(#bounds_of)*
_ => embedded_graphics::primitives::Rectangle::zero(),
}
};
let translate_child_impl = quote! {
match index {
#(#translate_child)*
_ => {}
}
};
let draw_impl = quote! {
#(#draw)*
};
(
field_count_impl,
index_impl,
index_mut_impl,
translate_impl,
draw_impl,
bounds_of_impl,
translate_child_impl,
)
}
Data::Enum(enum_data) => {
let mut enum_field_counts = Vec::new();
let mut enum_translates = Vec::new();
let mut enum_indexes = Vec::new();
let mut enum_mut_indexes = Vec::new();
let mut enum_draws = Vec::new();
let mut enum_bounds_ofs = Vec::new();
let mut enum_translate_childs = Vec::new();
enum_data.variants.iter().for_each(|variant| {
let variant_name = &variant.ident;
let (
enum_field_count,
enum_translate,
enum_index,
enum_mut_index,
enum_draw,
enum_bounds_of,
enum_translate_child,
) = match &variant.fields {
Fields::Named(FieldsNamed { named, .. }) => {
let field_idents = named
.iter()
.map(|field| field.ident.as_ref().unwrap())
.collect::<Vec<_>>();
let fields_count = named.iter().count();
let enum_field_count = quote! {
Self::#variant_name { .. } => {
#fields_count
}
};
let translate_fields = field_idents
.iter()
.map(|f| quote!(#f: #f.clone().translate(by)));
let enum_translate = quote! {
Self::#variant_name { #(#field_idents,)* } => {
Self::#variant_name {
#(#translate_fields,)*
}
}
};
let fields_index = field_idents
.iter()
.enumerate()
.map(|(i, f)| quote!(#i => #f,))
.collect::<Vec<_>>();
let enum_index = quote! {
Self::#variant_name { #(#field_idents,)* } => {
match index {
#(#fields_index)*
_ => #empty_vg_instance,
}
}
};
let enum_mut_index = quote! {
Self::#variant_name { #(#field_idents,)* } => {
match index {
#(#fields_index)*
_ => #empty_vg_instance_mut,
}
}
};
let fields_draw = field_idents.iter().map(|f| quote!(#f.draw(display)?;));
let enum_draw = quote! {
Self::#variant_name { #(#field_idents,)* } => {
#(#fields_draw)*
}
};
let fields_bounds_of = field_idents
.iter()
.enumerate()
.map(|(i, f)| quote!(#i => #f.bounds(),));
let enum_bounds_of = quote! {
Self::#variant_name { #(#field_idents,)* } => {
match index {
#(#fields_bounds_of)*
_ => embedded_graphics::primitives::Rectangle::zero(),
}
}
};
let fields_translate_child = field_idents
.iter()
.enumerate()
.map(|(i, f)| quote!(#i => #f.translate_impl(by),));
let enum_translate_child = quote! {
Self::#variant_name { #(#field_idents,)* } => {
match index {
#(#fields_translate_child)*
_ => {},
}
}
};
(
enum_field_count,
enum_translate,
enum_index,
enum_mut_index,
enum_draw,
enum_bounds_of,
enum_translate_child,
)
}
Fields::Unnamed(FieldsUnnamed { unnamed, .. }) => {
let field_idents = unnamed
.iter()
.enumerate()
.map(|(num, _)| format_ident!("__self_{}", num))
.collect::<Vec<_>>();
let fields_count = unnamed.iter().count();
let enum_field_count = quote! {
Self::#variant_name(..) => {
#fields_count
}
};
let translate_fields = field_idents
.iter()
.map(|f| quote!(#f.clone().translate(by), ));
let enum_translate = quote! {
Self::#variant_name(#(#field_idents),*) => {
Self::#variant_name(
#(#translate_fields)*
)
}
};
let fields_index = field_idents
.iter()
.enumerate()
.map(|(i, f)| quote!(#i => #f,))
.collect::<Vec<_>>();
let enum_index = quote! {
Self::#variant_name(#(#field_idents),*) => {
match index {
#(#fields_index)*
_ => #empty_vg_instance,
}
}
};
let enum_mut_index = quote! {
Self::#variant_name(#(#field_idents),*) => {
match index {
#(#fields_index)*
_ => #empty_vg_instance_mut,
}
}
};
let field_draws = field_idents.iter().map(|f| quote!(#f.draw(display)?;));
let enum_draw = quote! {
Self::#variant_name(#(#field_idents),*) => {
#(#field_draws)*
}
};
let fields_bounds_of = field_idents
.iter()
.enumerate()
.map(|(i, f)| quote!(#i => #f.bounds(),));
let enum_bounds_of = quote! {
Self::#variant_name(#(#field_idents),*) => {
match index {
#(#fields_bounds_of)*
_ => embedded_graphics::primitives::Rectangle::zero(),
}
}
};
let fields_translate_child = field_idents
.iter()
.enumerate()
.map(|(i, f)| quote!(#i => #f.translate_impl(by),));
let enum_translate_child = quote! {
Self::#variant_name(#(#field_idents),*) => {
match index {
#(#fields_translate_child)*
_ => {},
}
}
};
(
enum_field_count,
enum_translate,
enum_index,
enum_mut_index,
enum_draw,
enum_bounds_of,
enum_translate_child,
)
}
Fields::Unit => {
let enum_field_count = quote! {
Self::#variant_name => 0,
};
let enum_translate = quote! {
Self::#variant_name => Self::#variant_name,
};
let enum_index = quote! {
Self::#variant_name => {
#empty_vg_instance
}
};
let enum_mut_index = quote! {
Self::#variant_name => {
#empty_vg_instance_mut
}
};
let enum_draw = quote! {
Self::#variant_name => {}
};
let enum_bounds_of = quote! {
Self::#variant_name => {
embedded_graphics::primitives::Rectangle::zero()
}
};
let enum_translate_child = quote! {
Self::#variant_name => {}
};
(
enum_field_count,
enum_translate,
enum_index,
enum_mut_index,
enum_draw,
enum_bounds_of,
enum_translate_child,
)
}
};
enum_field_counts.push(enum_field_count);
enum_translates.push(enum_translate);
enum_indexes.push(enum_index);
enum_mut_indexes.push(enum_mut_index);
enum_draws.push(enum_draw);
enum_bounds_ofs.push(enum_bounds_of);
enum_translate_childs.push(enum_translate_child);
});
let field_count_impl = quote! {
match self {
#(#enum_field_counts)*
}
};
let index_impl = quote! {
match self {
#(#enum_indexes)*
}
};
let index_mut_impl = quote! {
match self {
#(#enum_mut_indexes)*
}
};
let translate_impl = quote! {
match self {
#(#enum_translates)*
}
};
let draw_impl = quote! {
match self {
#(#enum_draws)*
}
};
let bounds_of_impl = quote! {
match self {
#(#enum_bounds_ofs)*
}
};
let translate_child_impl = quote! {
match self {
#(#enum_translate_childs)*
}
};
(
field_count_impl,
index_impl,
index_mut_impl,
translate_impl,
draw_impl,
bounds_of_impl,
translate_child_impl,
)
}
_ => panic!("derive(ViewGroup) only supports structs with named fields and enums"),
};
let (impl_generics, ty_generics, where_clause) = ast.generics.split_for_impl();
let name = &ast.ident;
let gen_view_group = quote! {
impl #impl_generics embedded_layout::view_group::ViewGroup for #name #ty_generics #where_clause {
#[inline]
fn len(&self) -> usize {
#field_count_impl
}
#[inline]
fn at(&self, index: usize) -> &dyn embedded_layout::View {
#index_impl
}
#[inline]
fn at_mut(&mut self, index: usize) -> &mut dyn embedded_layout::View {
#index_mut_impl
}
#[inline]
fn bounds_of(&self, index: usize) -> embedded_graphics::primitives::Rectangle {
use embedded_layout::View;
#bounds_of_impl
}
#[inline]
fn translate_child(&mut self, index: usize, by: Point) {
use embedded_layout::View;
#translate_child_impl
}
}
impl #impl_generics embedded_graphics::transform::Transform for #name #ty_generics #where_clause {
#[inline]
fn translate(&self, by: Point) -> Self {
#translate_impl
}
#[inline]
fn translate_mut(&mut self, by: Point) -> &mut Self {
embedded_layout::view_group::ViewGroupHelper::translate(self, by);
self
}
}
impl #impl_generics embedded_graphics::geometry::Dimensions for #name #ty_generics #where_clause {
#[inline]
fn bounding_box(&self) -> embedded_graphics::primitives::Rectangle {
embedded_layout::view_group::ViewGroupHelper::bounds(self)
}
}
};
let pixelcolor = ast.generics.params.iter().find_map(|p| {
if let GenericParam::Type(tp) = p {
if tp.bounds.iter().any(is_type_param("PixelColor")) {
Some(tp.ident.clone())
} else {
None
}
} else {
None
}
});
let gen_drawable_impl = if let Some(pixelcolor) = pixelcolor {
quote! {
impl #impl_generics embedded_graphics::Drawable for #name #ty_generics #where_clause {
type Color = #pixelcolor;
type Output = ();
#[inline]
fn draw<D: embedded_graphics::draw_target::DrawTarget<Color = #pixelcolor>>(&self, display: &mut D) -> Result<(), D::Error> {
#draw_impl
Ok(())
}
}
}
} else {
quote!()
};
let generated = quote! {
#gen_view_group
#gen_drawable_impl
};
TokenStream::from(generated)
}
fn is_type_param(ident: &'static str) -> impl Fn(&TypeParamBound) -> bool {
move |f: &TypeParamBound| -> bool {
if let TypeParamBound::Trait(tpb) = f {
tpb.path
.segments
.iter()
.last()
.map(|segment| segment.ident == ident)
.unwrap_or(false)
} else {
false
}
}
}