gtk4_macros/
composite_template_derive.rs

1// Take a look at the license at the top of the repository in the LICENSE file.
2
3#[cfg(feature = "xml_validation")]
4use std::collections::HashMap;
5
6use proc_macro2::{Span, TokenStream};
7#[cfg(feature = "xml_validation")]
8use quick_xml::name::QName;
9use quote::quote;
10use syn::{Data, Error, Result};
11
12#[cfg(feature = "blueprint")]
13use crate::blueprint::*;
14use crate::{attribute_parser::*, util::*};
15
16fn gen_set_template(source: &TemplateSource, crate_ident: &proc_macro2::Ident) -> TokenStream {
17    match source {
18        TemplateSource::File(file) => {
19            let template = if file.ends_with(".blp") {
20                if cfg!(feature = "blueprint") {
21                    let Some(local_file) = Span::call_site().local_file() else {
22                        return Error::new(Span::call_site(), "File not found")
23                            .into_compile_error();
24                    };
25                    let local_file = local_file.to_str();
26                    quote! {
27                        #crate_ident::gtk4_macros::include_blueprint!(#local_file, #file).as_bytes()
28                    }
29                } else {
30                    panic!("blueprint feature is disabled")
31                }
32            } else {
33                quote! {
34                    include_bytes!(#file)
35                }
36            };
37
38            quote! {
39                #crate_ident::subclass::widget::WidgetClassExt::set_template_static(
40                        klass,
41                        #template,
42                );
43            }
44        }
45        TemplateSource::Resource(resource) => quote! {
46            #crate_ident::subclass::widget::WidgetClassExt::set_template_from_resource(
47                klass,
48                &#resource,
49            );
50        },
51        TemplateSource::Xml(template) => quote! {
52            #crate_ident::subclass::widget::WidgetClassExt::set_template_static(
53                klass,
54                #template.as_bytes(),
55            );
56        },
57        #[cfg(feature = "blueprint")]
58        TemplateSource::Blueprint(blueprint) => {
59            let template =
60                compile_blueprint(blueprint.as_bytes()).expect("can't compile blueprint");
61
62            quote! {
63                #crate_ident::subclass::widget::WidgetClassExt::set_template_static(
64                    klass,
65                    #template.as_bytes(),
66                );
67            }
68        }
69    }
70}
71
72#[cfg(feature = "xml_validation")]
73fn check_template_fields(source: &TemplateSource, fields: &[AttributedField]) -> Result<()> {
74    #[allow(unused_assignments)]
75    let xml = match source {
76        TemplateSource::Xml(template) => template,
77        _ => return Ok(()),
78    };
79
80    let mut reader = quick_xml::Reader::from_str(xml);
81    let mut ids_left = fields
82        .iter()
83        .map(|field| match field.attr.ty {
84            FieldAttributeType::TemplateChild => (field.id(), field.id_span()),
85        })
86        .collect::<HashMap<_, _>>();
87
88    loop {
89        use quick_xml::events::Event;
90
91        let event = reader.read_event();
92        let elem = match &event {
93            Ok(Event::Start(e)) => Some(e),
94            Ok(Event::Empty(e)) => Some(e),
95            Ok(Event::Eof) => break,
96            Err(e) => {
97                return Err(Error::new(
98                    Span::call_site(),
99                    format!(
100                        "Failed reading template XML at position {}: {:?}",
101                        reader.buffer_position(),
102                        e
103                    ),
104                ));
105            }
106            _ => None,
107        };
108        if let Some(e) = elem {
109            let name = e.name();
110            if name == QName(b"object") || name == QName(b"template") {
111                let id = e
112                    .attributes()
113                    .find_map(|a| a.ok().and_then(|a| (a.key == QName(b"id")).then_some(a)));
114                let id = id.as_ref().and_then(|a| std::str::from_utf8(&a.value).ok());
115                if let Some(id) = id {
116                    ids_left.remove(id);
117                }
118            }
119        }
120    }
121
122    if let Some((name, span)) = ids_left.into_iter().next() {
123        return Err(Error::new(
124            span,
125            format!("Template child with id `{name}` not found in template XML",),
126        ));
127    }
128
129    Ok(())
130}
131
132fn gen_template_child_bindings(fields: &[AttributedField]) -> TokenStream {
133    let crate_ident = crate_ident_new();
134
135    let recurse = fields.iter().map(|field| match field.attr.ty {
136        FieldAttributeType::TemplateChild => {
137            let mut value_id = &field.ident.to_string();
138            let ident = &field.ident;
139            let mut value_internal = false;
140            field.attr.args.iter().for_each(|arg| match arg {
141                FieldAttributeArg::Id(value, _) => {
142                    value_id = value;
143                }
144                FieldAttributeArg::Internal(internal) => {
145                    value_internal = *internal;
146                }
147            });
148
149            quote! {
150                klass.bind_template_child_with_offset(
151                    &#value_id,
152                    #value_internal,
153                    #crate_ident::offset_of!(Self => #ident),
154                );
155            }
156        }
157    });
158
159    quote! {
160        #(#recurse)*
161    }
162}
163
164fn gen_template_child_type_checks(fields: &[AttributedField]) -> TokenStream {
165    let crate_ident = crate_ident_new();
166
167    let recurse = fields.iter().map(|field| match field.attr.ty {
168        FieldAttributeType::TemplateChild => {
169            let ty = &field.ty;
170            let ident = &field.ident;
171            let type_err = format!("Template child with id `{}` has incompatible type. XML has {{:?}}, struct has {{:?}}", field.id());
172            quote! {
173                let ty = <<#ty as ::std::ops::Deref>::Target as #crate_ident::glib::prelude::StaticType>::static_type();
174                let child_ty = #crate_ident::glib::prelude::ObjectExt::type_(::std::ops::Deref::deref(&imp.#ident));
175                if !child_ty.is_a(ty) {
176                    panic!(#type_err, child_ty, ty);
177                }
178            }
179        }
180    });
181
182    quote! {
183        #(#recurse)*
184    }
185}
186
187pub fn impl_composite_template(input: &syn::DeriveInput) -> Result<TokenStream> {
188    let name = &input.ident;
189    let crate_ident = crate_ident_new();
190
191    let template = match parse_template_source(input) {
192        Ok(v) => Some(v),
193        Err(e) => {
194            return Err(Error::new(
195                Span::call_site(),
196                format!(
197                    "{e}: derive(CompositeTemplate) requires #[template(...)] to specify 'file', 'resource', or 'string'"
198                ),
199            ));
200        }
201    };
202
203    let allow_without_attribute = template
204        .as_ref()
205        .map(|t| t.allow_template_child_without_attribute)
206        .unwrap_or(false);
207    let source = template.as_ref().map(|t| &t.source);
208
209    let set_template = source.map(|s| gen_set_template(s, &crate_ident));
210
211    let fields = match input.data {
212        Data::Struct(ref s) => Some(&s.fields),
213        _ => {
214            return Err(Error::new(
215                Span::call_site(),
216                "derive(CompositeTemplate) only supports structs",
217            ));
218        }
219    };
220
221    let attributed_fields = match fields.map(|f| parse_fields(f, allow_without_attribute)) {
222        Some(fields) => fields?,
223        None => vec![],
224    };
225
226    #[cfg(feature = "xml_validation")]
227    {
228        if let Some(source) = source {
229            check_template_fields(source, &attributed_fields)?;
230        }
231    }
232    let template_children = gen_template_child_bindings(&attributed_fields);
233    let checks = gen_template_child_type_checks(&attributed_fields);
234
235    Ok(quote! {
236        impl #crate_ident::subclass::widget::CompositeTemplate for #name {
237            fn bind_template(klass: &mut Self::Class) {
238                #set_template
239
240                unsafe {
241                    #template_children
242                }
243            }
244            fn check_template_children(widget: &<Self as #crate_ident::glib::subclass::prelude::ObjectSubclass>::Type) {
245                let imp = #crate_ident::subclass::prelude::ObjectSubclassIsExt::imp(widget);
246                #checks
247            }
248        }
249    })
250}
gtk4_macros/composite_template_derive.rs

gtk4_macros/
composite_template_derive.rs
