gtk4_macros/
composite_template_derive.rs#[cfg(feature = "xml_validation")]
use std::collections::HashMap;
use proc_macro2::{Span, TokenStream};
#[cfg(feature = "xml_validation")]
use quick_xml::name::QName;
use quote::quote;
use syn::{Data, Error, Result};
#[cfg(feature = "blueprint")]
use crate::blueprint::*;
use crate::{attribute_parser::*, util::*};
fn gen_set_template(source: &TemplateSource, crate_ident: &proc_macro2::Ident) -> TokenStream {
match source {
TemplateSource::File(file) => {
let template = if file.ends_with(".blp") {
if cfg!(feature = "blueprint") {
quote! {
#crate_ident::gtk4_macros::include_blueprint!(#file).as_bytes()
}
} else {
panic!("blueprint feature is disabled")
}
} else {
quote! {
include_bytes!(#file)
}
};
quote! {
#crate_ident::subclass::widget::WidgetClassExt::set_template_static(
klass,
#template,
);
}
}
TemplateSource::Resource(resource) => quote! {
#crate_ident::subclass::widget::WidgetClassExt::set_template_from_resource(
klass,
&#resource,
);
},
TemplateSource::Xml(template) => quote! {
#crate_ident::subclass::widget::WidgetClassExt::set_template_static(
klass,
#template.as_bytes(),
);
},
#[cfg(feature = "blueprint")]
TemplateSource::Blueprint(blueprint) => {
let template =
compile_blueprint(blueprint.as_bytes()).expect("can't compile blueprint");
quote! {
#crate_ident::subclass::widget::WidgetClassExt::set_template_static(
klass,
#template.as_bytes(),
);
}
}
}
}
#[cfg(feature = "xml_validation")]
fn check_template_fields(source: &TemplateSource, fields: &[AttributedField]) -> Result<()> {
#[allow(unused_assignments)]
let xml = match source {
TemplateSource::Xml(template) => template,
_ => return Ok(()),
};
let mut reader = quick_xml::Reader::from_str(xml);
let mut ids_left = fields
.iter()
.map(|field| match field.attr.ty {
FieldAttributeType::TemplateChild => (field.id(), field.id_span()),
})
.collect::<HashMap<_, _>>();
loop {
use quick_xml::events::Event;
let event = reader.read_event();
let elem = match &event {
Ok(Event::Start(e)) => Some(e),
Ok(Event::Empty(e)) => Some(e),
Ok(Event::Eof) => break,
Err(e) => {
return Err(Error::new(
Span::call_site(),
format!(
"Failed reading template XML at position {}: {:?}",
reader.buffer_position(),
e
),
));
}
_ => None,
};
if let Some(e) = elem {
let name = e.name();
if name == QName(b"object") || name == QName(b"template") {
let id = e
.attributes()
.find_map(|a| a.ok().and_then(|a| (a.key == QName(b"id")).then_some(a)));
let id = id.as_ref().and_then(|a| std::str::from_utf8(&a.value).ok());
if let Some(id) = id {
ids_left.remove(id);
}
}
}
}
if let Some((name, span)) = ids_left.into_iter().next() {
return Err(Error::new(
span,
format!("Template child with id `{name}` not found in template XML",),
));
}
Ok(())
}
fn gen_template_child_bindings(fields: &[AttributedField]) -> TokenStream {
let crate_ident = crate_ident_new();
let recurse = fields.iter().map(|field| match field.attr.ty {
FieldAttributeType::TemplateChild => {
let mut value_id = &field.ident.to_string();
let ident = &field.ident;
let mut value_internal = false;
field.attr.args.iter().for_each(|arg| match arg {
FieldAttributeArg::Id(value, _) => {
value_id = value;
}
FieldAttributeArg::Internal(internal) => {
value_internal = *internal;
}
});
quote! {
klass.bind_template_child_with_offset(
&#value_id,
#value_internal,
#crate_ident::offset_of!(Self => #ident),
);
}
}
});
quote! {
#(#recurse)*
}
}
fn gen_template_child_type_checks(fields: &[AttributedField]) -> TokenStream {
let crate_ident = crate_ident_new();
let recurse = fields.iter().map(|field| match field.attr.ty {
FieldAttributeType::TemplateChild => {
let ty = &field.ty;
let ident = &field.ident;
let type_err = format!("Template child with id `{}` has incompatible type. XML has {{:?}}, struct has {{:?}}", field.id());
quote! {
let ty = <<#ty as ::std::ops::Deref>::Target as #crate_ident::glib::prelude::StaticType>::static_type();
let child_ty = #crate_ident::glib::prelude::ObjectExt::type_(::std::ops::Deref::deref(&imp.#ident));
if !child_ty.is_a(ty) {
panic!(#type_err, child_ty, ty);
}
}
}
});
quote! {
#(#recurse)*
}
}
pub fn impl_composite_template(input: &syn::DeriveInput) -> Result<TokenStream> {
let name = &input.ident;
let crate_ident = crate_ident_new();
let template = match parse_template_source(input) {
Ok(v) => Some(v),
Err(e) => {
return Err(Error::new(
Span::call_site(),
format!("{}: derive(CompositeTemplate) requires #[template(...)] to specify 'file', 'resource', or 'string'",
e)
));
}
};
let allow_without_attribute = template
.as_ref()
.map(|t| t.allow_template_child_without_attribute)
.unwrap_or(false);
let source = template.as_ref().map(|t| &t.source);
let set_template = source.map(|s| gen_set_template(s, &crate_ident));
let fields = match input.data {
Data::Struct(ref s) => Some(&s.fields),
_ => {
return Err(Error::new(
Span::call_site(),
"derive(CompositeTemplate) only supports structs",
));
}
};
let attributed_fields = match fields.map(|f| parse_fields(f, allow_without_attribute)) {
Some(fields) => fields?,
None => vec![],
};
#[cfg(feature = "xml_validation")]
{
if let Some(source) = source {
check_template_fields(source, &attributed_fields)?;
}
}
let template_children = gen_template_child_bindings(&attributed_fields);
let checks = gen_template_child_type_checks(&attributed_fields);
Ok(quote! {
impl #crate_ident::subclass::widget::CompositeTemplate for #name {
fn bind_template(klass: &mut Self::Class) {
#set_template
unsafe {
#template_children
}
}
fn check_template_children(widget: &<Self as #crate_ident::glib::subclass::prelude::ObjectSubclass>::Type) {
let imp = #crate_ident::subclass::prelude::ObjectSubclassIsExt::imp(widget);
#checks
}
}
})
}