Fix docs

Author: lambda-fairy

docs/src/bin/build_nav.rs

@@ -1,7 +1,7 @@
 use comrak::{self, nodes::AstNode, Arena};
 use docs::{
     page::{Page, COMRAK_OPTIONS},
-    string_writer::StringWriter,
+    text_writer::TextWriter,
 };
 use std::{env, error::Error, fs, io, path::Path, str};
 
@@ -51,7 +51,7 @@ fn load_page_title<'a>(
     let page = Page::load(arena, path)?;
     let title = page.title.map(|title| {
         let mut buffer = String::new();
-        comrak::format_commonmark(title, &COMRAK_OPTIONS, &mut StringWriter(&mut buffer)).unwrap();
+        comrak::format_commonmark(title, &COMRAK_OPTIONS, &mut TextWriter(&mut buffer)).unwrap();
         buffer
     });
     Ok(title)

docs/src/lib.rs

@@ -1,5 +1,5 @@
 #![feature(once_cell)]
 
 pub mod page;
-pub mod string_writer;
+pub mod text_writer;
 pub mod views;

docs/src/string_writer.rs

@@ -0,0 +1,18 @@
+use std::{fmt, io, str};
+
+pub struct TextWriter<T>(pub T);
+
+impl<T: fmt::Write> io::Write for TextWriter<T> {
+    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
+        let s =
+            str::from_utf8(buf).map_err(|err| io::Error::new(io::ErrorKind::InvalidData, err))?;
+        self.0
+            .write_str(s)
+            .map_err(|err| io::Error::new(io::ErrorKind::Other, err))?;
+        Ok(buf.len())
+    }
+
+    fn flush(&mut self) -> io::Result<()> {
+        Ok(())
+    }
+}

docs/src/text_writer.rs

@@ -1,30 +1,37 @@
 use comrak::nodes::AstNode;
-use maud::{html, Markup, PreEscaped, Render, DOCTYPE};
+use maud::{html, Html, ToHtml, DOCTYPE};
 use std::str;
 
 use crate::{
     page::{Page, COMRAK_OPTIONS},
-    string_writer::StringWriter,
+    text_writer::TextWriter,
 };
 
 struct Comrak<'a>(&'a AstNode<'a>);
 
-impl<'a> Render for Comrak<'a> {
-    fn render_to(&self, buffer: &mut String) {
-        comrak::format_html(self.0, &COMRAK_OPTIONS, &mut StringWriter(buffer)).unwrap();
+impl<'a> ToHtml for Comrak<'a> {
+    fn html(&self, buffer: &mut Html) {
+        // XSS-Safety: The input Markdown comes from docs, which are trusted.
+        comrak::format_html(
+            self.0,
+            &COMRAK_OPTIONS,
+            &mut TextWriter(buffer.as_mut_string_unchecked()),
+        )
+        .unwrap();
     }
 }
 
 /// Hack! Comrak wraps a single line of input in `<p>` tags, which is great in
 /// general but not suitable for links in the navigation bar.
 struct ComrakRemovePTags<'a>(&'a AstNode<'a>);
 
-impl<'a> Render for ComrakRemovePTags<'a> {
-    fn render(&self) -> Markup {
+impl<'a> ToHtml for ComrakRemovePTags<'a> {
+    fn to_html(&self) -> Html {
         let mut buffer = String::new();
-        comrak::format_html(self.0, &COMRAK_OPTIONS, &mut StringWriter(&mut buffer)).unwrap();
+        comrak::format_html(self.0, &COMRAK_OPTIONS, &mut TextWriter(&mut buffer)).unwrap();
         assert!(buffer.starts_with("<p>") && buffer.ends_with("</p>\n"));
-        PreEscaped(
+        // XSS-Safety: The input Markdown comes from docs, which are trusted.
+        Html::from_unchecked(
             buffer
                 .trim_start_matches("<p>")
                 .trim_end_matches("</p>\n")
@@ -35,9 +42,9 @@ impl<'a> Render for ComrakRemovePTags<'a> {
 
 struct ComrakText<'a>(&'a AstNode<'a>);
 
-impl<'a> Render for ComrakText<'a> {
-    fn render_to(&self, buffer: &mut String) {
-        comrak::format_commonmark(self.0, &COMRAK_OPTIONS, &mut StringWriter(buffer)).unwrap();
+impl<'a> ToHtml for ComrakText<'a> {
+    fn html(&self, buffer: &mut Html) {
+        comrak::format_commonmark(self.0, &COMRAK_OPTIONS, &mut TextWriter(buffer)).unwrap();
     }
 }
 
@@ -47,7 +54,7 @@ pub fn main<'a>(
     nav: &[(&str, &'a AstNode<'a>)],
     version: &str,
     hash: &str,
-) -> Markup {
+) -> Html {
     html! {
         (DOCTYPE)
         meta charset="utf-8";