Make Escape and EscapeBodyText support lazy processing

Author: yotamofek

src/librustdoc/html/escape.rs

@@ -7,7 +7,7 @@ use std::fmt;
 
 use unicode_segmentation::UnicodeSegmentation;
 
-#[inline(always)]
+#[inline]
 fn escape(s: &str, mut w: impl fmt::Write, escape_quotes: bool) -> fmt::Result {
     // Because the internet is always right, turns out there's not that many
     // characters to escape: http://stackoverflow.com/questions/7381974
@@ -35,13 +35,30 @@ fn escape(s: &str, mut w: impl fmt::Write, escape_quotes: bool) -> fmt::Result {
     Ok(())
 }
 
+struct WriteEscaped<W: fmt::Write> {
+    writer: W,
+    escape_quotes: bool,
+}
+
+impl<W: fmt::Write> fmt::Write for WriteEscaped<W> {
+    #[inline]
+    fn write_str(&mut self, s: &str) -> fmt::Result {
+        escape(s, &mut self.writer, self.escape_quotes)
+    }
+}
+
 /// Wrapper struct which will emit the HTML-escaped version of the contained
 /// string when passed to a format string.
-pub(crate) struct Escape<'a>(pub &'a str);
+pub(crate) struct Escape<T>(pub T);
 
-impl fmt::Display for Escape<'_> {
+impl<T: fmt::Display> fmt::Display for Escape<T> {
+    #[inline]
     fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
-        escape(self.0, fmt, true)
+        self.0.fmt(
+            &mut fmt
+                .options()
+                .create_formatter(&mut WriteEscaped { writer: fmt, escape_quotes: true }),
+        )
     }
 }
 
@@ -51,11 +68,15 @@ impl fmt::Display for Escape<'_> {
 /// This is only safe to use for text nodes. If you need your output to be
 /// safely contained in an attribute, use [`Escape`]. If you don't know the
 /// difference, use [`Escape`].
-pub(crate) struct EscapeBodyText<'a>(pub &'a str);
+pub(crate) struct EscapeBodyText<T>(pub T);
 
-impl fmt::Display for EscapeBodyText<'_> {
+impl<T: fmt::Display> fmt::Display for EscapeBodyText<T> {
     fn fmt(&self, fmt: &mut fmt::Formatter<'_>) -> fmt::Result {
-        escape(self.0, fmt, false)
+        self.0.fmt(
+            &mut fmt
+                .options()
+                .create_formatter(&mut WriteEscaped { writer: fmt, escape_quotes: false }),
+        )
     }
 }
 

src/librustdoc/html/escape/tests.rs

@@ -1,3 +1,11 @@
+use std::iter;
+
+#[test]
+fn escape() {
+    use super::Escape as E;
+    assert_eq!(format!("<Hello> {}", E("<World>")), "<Hello> &lt;World&gt;");
+}
+
 // basic examples
 #[test]
 fn escape_body_text_with_wbr() {

src/librustdoc/html/format.rs

@@ -853,7 +853,7 @@ pub(crate) fn anchor<'a: 'cx, 'cx>(
                 f,
                 r#"<a class="{short_ty}" href="{url}" title="{short_ty} {path}">{text}</a>"#,
                 path = join_with_double_colon(&fqp),
-                text = EscapeBodyText(text.as_str()),
+                text = EscapeBodyText(text),
             )
         } else {
             f.write_str(text.as_str())

src/librustdoc/html/render/mod.rs

@@ -720,7 +720,7 @@ fn short_item_info(
             }
             DeprecatedSince::Future => String::from("Deprecating in a future version"),
             DeprecatedSince::NonStandard(since) => {
-                format!("Deprecated since {}", Escape(since.as_str()))
+                format!("Deprecated since {}", Escape(since))
             }
             DeprecatedSince::Unspecified | DeprecatedSince::Err => String::from("Deprecated"),
         };
@@ -1519,7 +1519,7 @@ pub(crate) fn notable_traits_button<'a, 'tcx>(
             write!(
                 f,
                 " <a href=\"#\" class=\"tooltip\" data-notable-ty=\"{ty}\">ⓘ</a>",
-                ty = Escape(&format!("{:#}", ty.print(cx))),
+                ty = Escape(ty.print(cx)),
             )
         })
     })

src/librustdoc/html/render/print_item.rs

@@ -534,12 +534,16 @@ fn extra_info_tags<'a, 'tcx: 'a>(
     import_def_id: Option<DefId>,
 ) -> impl Display + 'a + Captures<'tcx> {
     fmt::from_fn(move |f| {
-        fn tag_html<'a>(class: &'a str, title: &'a str, contents: &'a str) -> impl Display + 'a {
+        fn tag_html<'a>(
+            class: impl fmt::Display + 'a,
+            title: impl fmt::Display + 'a,
+            contents: impl fmt::Display + 'a,
+        ) -> impl Display + 'a {
             fmt::from_fn(move |f| {
                 write!(
                     f,
                     r#"<wbr><span class="stab {class}" title="{title}">{contents}</span>"#,
-                    title = Escape(title),
+                    title = Escape(&title),
                 )
             })
         }

src/librustdoc/lib.rs

@@ -8,6 +8,7 @@
 #![feature(debug_closure_helpers)]
 #![feature(file_buffered)]
 #![feature(format_args_nl)]
+#![feature(formatting_options)]
 #![feature(if_let_guard)]
 #![feature(impl_trait_in_assoc_type)]
 #![feature(iter_intersperse)]