Optimize Content::has, Introspector::query_label, and MetaElem (#2759)

crates/typst-macros/src/elem.rs

@@ -738,6 +738,27 @@ fn create_native_elem_impl(element: &Elem) -> TokenStream {
         }
     });
 
+    // Fields that can be checked using the `has` method.
+    let field_has_matches = element.visible_fields().map(|field| {
+        let elem = &element.ident;
+        let name = &field.enum_ident;
+        let field_ident = &field.ident;
+
+        if field.ghost {
+            quote! {
+                <#elem as #foundations::ElementFields>::Fields::#name => false,
+            }
+        } else if field.inherent() {
+            quote! {
+                <#elem as #foundations::ElementFields>::Fields::#name => true,
+            }
+        } else {
+            quote! {
+                <#elem as #foundations::ElementFields>::Fields::#name => self.#field_ident.is_some(),
+            }
+        }
+    });
+
     // Fields that can be set using the `set_field` method.
     let field_set_matches = element
         .visible_fields()
@@ -888,6 +909,10 @@ fn create_native_elem_impl(element: &Elem) -> TokenStream {
         })
         .unwrap_or_else(|| quote! { None });
 
+    let label_has_field = element
+        .unless_capability("Unlabellable", || quote! { self.label().is_some() })
+        .unwrap_or_else(|| quote! { false });
+
     let mark_prepared = element
         .unless_capability("Unlabellable", || quote! { self.prepared = true; })
         .unwrap_or_else(|| quote! {});
@@ -1026,6 +1051,18 @@ fn create_native_elem_impl(element: &Elem) -> TokenStream {
                 }
             }
 
+            fn has(&self, id: u8) -> bool {
+                let Ok(id) = <#ident as #foundations::ElementFields>::Fields::try_from(id) else {
+                    return false;
+                };
+
+                match id {
+                    <#ident as #foundations::ElementFields>::Fields::Label => #label_has_field,
+                    #(#field_has_matches)*
+                    _ => false,
+                }
+            }
+
             fn fields(&self) -> #foundations::Dict {
                 let mut fields = #foundations::Dict::new();
                 #(#field_dict)*

crates/typst/src/foundations/content.rs

@@ -535,7 +535,7 @@ impl Content {
             return false;
         };
 
-        self.get(id).is_some()
+        self.0.has(id)
     }
 
     /// Access the specified field on the content. Returns the default value if

crates/typst/src/foundations/element.rs

@@ -265,6 +265,9 @@ pub trait NativeElement: Debug + Repr + Construct + Set + Send + Sync + 'static
     /// Get the field with the given field ID.
     fn field(&self, id: u8) -> Option<Value>;
 
+    /// Whether the element has the given field set.
+    fn has(&self, id: u8) -> bool;
+
     /// Set the field with the given ID.
     fn set_field(&mut self, id: u8, value: Value) -> StrResult<()>;
 

crates/typst/src/introspection/introspector.rs

@@ -195,13 +195,13 @@ impl Introspector {
     }
 
     /// Query for a unique element with the label.
-    pub fn query_label(&self, label: Label) -> StrResult<Prehashed<Content>> {
+    pub fn query_label(&self, label: Label) -> StrResult<&Prehashed<Content>> {
         let mut found = None;
         for elem in self.all().filter(|elem| elem.label() == Some(label)) {
             if found.is_some() {
                 bail!("label `{}` occurs multiple times in the document", label.repr());
             }
-            found = Some(elem.clone());
+            found = Some(elem);
         }
         found.ok_or_else(|| {
             eco_format!("label `{}` does not exist in the document", label.repr())

crates/typst/src/introspection/mod.rs

@@ -27,6 +27,7 @@ use smallvec::SmallVec;
 
 use crate::foundations::{
     cast, category, elem, ty, Behave, Behaviour, Category, Content, Repr, Scope,
+    Unlabellable,
 };
 use crate::layout::PdfPageLabel;
 use crate::model::{Destination, Numbering};
@@ -53,7 +54,7 @@ pub fn define(global: &mut Scope) {
 }
 
 /// Hosts metadata and ensures metadata is produced even for empty elements.
-#[elem(Behave)]
+#[elem(Behave, Unlabellable)]
 pub struct MetaElem {
     /// Metadata that should be attached to all elements affected by this style
     /// property.
@@ -61,6 +62,8 @@ pub struct MetaElem {
     pub data: SmallVec<[Meta; 1]>,
 }
 
+impl Unlabellable for MetaElem {}
+
 impl Behave for MetaElem {
     fn behaviour(&self) -> Behaviour {
         Behaviour::Invisible

crates/typst/src/model/footnote.rs

@@ -1,8 +1,6 @@
 use std::num::NonZeroUsize;
 use std::str::FromStr;
 
-use comemo::Prehashed;
-
 use crate::diag::{bail, At, SourceResult, StrResult};
 use crate::engine::Engine;
 use crate::foundations::{
@@ -111,8 +109,7 @@ impl FootnoteElem {
     pub fn declaration_location(&self, engine: &Engine) -> StrResult<Location> {
         match self.body() {
             FootnoteBody::Reference(label) => {
-                let element: Prehashed<Content> =
-                    engine.introspector.query_label(*label)?;
+                let element = engine.introspector.query_label(*label)?;
                 let footnote = element
                     .to::<FootnoteElem>()
                     .ok_or("referenced element should be a footnote")?;

crates/typst/src/model/reference.rs

@@ -148,7 +148,7 @@ impl Synthesize for RefElem {
 
         let target = *self.target();
         if !BibliographyElem::has(engine, target) {
-            if let Ok(elem) = engine.introspector.query_label(target) {
+            if let Ok(elem) = engine.introspector.query_label(target).cloned() {
                 self.push_element(Some(elem.into_inner()));
                 return Ok(());
             }
@@ -180,6 +180,7 @@ impl Show for RefElem {
                 return Ok(FootnoteElem::with_label(target).spanned(span).pack());
             }
 
+            let elem = elem.clone();
             let refable = elem
                 .with::<dyn Refable>()
                 .ok_or_else(|| {
@@ -213,17 +214,16 @@ impl Show for RefElem {
                 ))
                 .at(span)?;
 
+            let loc = elem.location().unwrap();
             let numbers = refable
                 .counter()
-                .at(engine, elem.location().unwrap())?
+                .at(engine, loc)?
                 .display(engine, &numbering.trimmed())?;
 
             let supplement = match self.supplement(styles).as_ref() {
                 Smart::Auto => refable.supplement(),
                 Smart::Custom(None) => Content::empty(),
-                Smart::Custom(Some(supplement)) => {
-                    supplement.resolve(engine, [(*elem).clone()])?
-                }
+                Smart::Custom(Some(supplement)) => supplement.resolve(engine, [elem])?,
             };
 
             let mut content = numbers;
@@ -231,7 +231,7 @@ impl Show for RefElem {
                 content = supplement + TextElem::packed("\u{a0}") + content;
             }
 
-            Ok(content.linked(Destination::Location(elem.location().unwrap())))
+            Ok(content.linked(Destination::Location(loc)))
         }))
     }
 }

crates/typst/src/realize/mod.rs

@@ -134,7 +134,7 @@ pub fn realize(
             let span = elem.span();
             let meta = Meta::Elem(elem.clone());
             return Ok(Some(
-                (elem + MetaElem::new().pack().spanned(span))
+                (elem + MetaElem::new().spanned(span).pack())
                     .styled(MetaElem::set_data(smallvec![meta])),
             ));
         }
@@ -758,6 +758,6 @@ impl<'a> CiteGroupBuilder<'a> {
 
     fn finish(self) -> (Content, StyleChain<'a>) {
         let span = self.items.first().map(|cite| cite.span()).unwrap_or(Span::detached());
-        (CiteGroup::new(self.items).pack().spanned(span), self.styles)
+        (CiteGroup::new(self.items).spanned(span).pack(), self.styles)
     }
 }