gtk4-macros: Support blueprint files in CompositeTemplate

Author: yuraiz

gtk4-macros/src/composite_template_derive.rs

@@ -17,12 +17,28 @@ use crate::{attribute_parser::*, util::*};
 
 fn gen_set_template(source: &TemplateSource, crate_ident: &proc_macro2::Ident) -> TokenStream {
     match source {
-        TemplateSource::File(file) => quote! {
-            #crate_ident::subclass::widget::WidgetClassSubclassExt::set_template_static(
-                klass,
-                include_bytes!(#file),
-            );
-        },
+        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::WidgetClassSubclassExt::set_template_static(
+                        klass,
+                        #template,
+                );
+            }
+        }
         TemplateSource::Resource(resource) => quote! {
             #crate_ident::subclass::widget::WidgetClassSubclassExt::set_template_from_resource(
                 klass,

gtk4-macros/src/lib.rs

@@ -15,6 +15,49 @@ use proc_macro::TokenStream;
 use proc_macro_error::proc_macro_error;
 use syn::{parse_macro_input, DeriveInput};
 
+/// That macro includes and compiles blueprint file by path relative to project rood
+///
+/// It expected to run inside composite_template_derive, not by users
+#[cfg(feature = "blueprint")]
+#[proc_macro]
+pub fn include_blueprint(input: TokenStream) -> TokenStream {
+    use quote::quote;
+
+    let tokens: Vec<_> = input.into_iter().collect();
+
+    if tokens.len() != 1 {
+        panic!("File name not found");
+    }
+
+    let root = std::env::var("CARGO_MANIFEST_DIR").unwrap_or_else(|_| ".".into());
+
+    let file_name = tokens[0].to_string();
+    let file_name = file_name.trim();
+    let file_name = &file_name[1..file_name.len() - 1];
+
+    let path = std::path::Path::new(&root).join(file_name);
+
+    if !path.exists() {
+        panic!("{path:?} not found");
+    }
+
+    let path = path.to_string_lossy().to_string();
+
+    let template = blueprint::compile_blueprint(
+        std::fs::read_to_string(&path)
+            .unwrap_or_else(|err| panic!("{err}"))
+            .as_bytes(),
+    )
+    .unwrap();
+
+    quote!({
+        // Compiler reruns macro if file changed
+        _ = include_str!(#path);
+        #template
+    })
+    .into()
+}
+
 /// Derive macro for using a composite template in a widget.
 ///
 /// The `template` attribute specifies where the template should be loaded

gtk4-macros/tests/my_widget.blp

@@ -0,0 +1,9 @@
+template MyWidget5 {
+    Label label {
+        label: 'foobar';
+    }
+
+    Label my_label2 {
+        label: 'foobaz';
+    }
+}

gtk4-macros/tests/templates.rs

@@ -256,3 +256,50 @@ glib::wrapper! {
 fn blueprint_template() {
     let _: MyWidget4 = glib::Object::new();
 }
+
+#[cfg(feature = "blueprint")]
+mod imp5 {
+    use super::*;
+
+    #[derive(Debug, Default, CompositeTemplate)]
+    #[template(file = "tests/my_widget.blp")]
+    pub struct MyWidget5 {
+        #[template_child]
+        pub label: TemplateChild<gtk::Label>,
+        #[template_child(id = "my_label2")]
+        pub label2: gtk::TemplateChild<gtk::Label>,
+    }
+
+    #[glib::object_subclass]
+    impl ObjectSubclass for MyWidget5 {
+        const NAME: &'static str = "MyWidget5";
+        type Type = super::MyWidget5;
+        type ParentType = gtk::Widget;
+        fn class_init(klass: &mut Self::Class) {
+            klass.bind_template();
+        }
+        fn instance_init(obj: &glib::subclass::InitializingObject<Self>) {
+            obj.init_template();
+        }
+    }
+
+    impl ObjectImpl for MyWidget5 {
+        fn dispose(&self) {
+            while let Some(child) = self.obj().first_child() {
+                child.unparent();
+            }
+        }
+    }
+    impl WidgetImpl for MyWidget5 {}
+}
+
+#[cfg(feature = "blueprint")]
+glib::wrapper! {
+    pub struct MyWidget5(ObjectSubclass<imp5::MyWidget5>) @extends gtk::Widget;
+}
+
+#[gtk::test]
+#[cfg(feature = "blueprint")]
+fn blueprint_file() {
+    let _: MyWidget5 = glib::Object::new();
+}