Make default syntax for highlighting optional

src/web/highlight.rs

@@ -49,10 +49,16 @@ fn try_with_syntax(syntax: &SyntaxReference, code: &str) -> Result<String> {
     Ok(html_generator.finalize())
 }
 
-fn select_syntax(name: Option<&str>, code: &str) -> &'static SyntaxReference {
+fn select_syntax(
+    name: Option<&str>,
+    code: &str,
+    default: Option<&str>,
+) -> &'static SyntaxReference {
     name.and_then(|name| {
         if name.is_empty() {
-            return SYNTAXES.find_syntax_by_token("rust");
+            if let Some(default) = default {
+                return SYNTAXES.find_syntax_by_token(default);
+            }
         }
         SYNTAXES.find_syntax_by_token(name).or_else(|| {
             name.rsplit_once('.')
@@ -63,12 +69,12 @@ fn select_syntax(name: Option<&str>, code: &str) -> &'static SyntaxReference {
     .unwrap_or_else(|| SYNTAXES.find_syntax_plain_text())
 }
 
-pub fn try_with_lang(lang: Option<&str>, code: &str) -> Result<String> {
-    try_with_syntax(select_syntax(lang, code), code)
+pub fn try_with_lang(lang: Option<&str>, code: &str, default: Option<&str>) -> Result<String> {
+    try_with_syntax(select_syntax(lang, code, default), code)
 }
 
-pub fn with_lang(lang: Option<&str>, code: &str) -> String {
-    match try_with_lang(lang, code) {
+pub fn with_lang(lang: Option<&str>, code: &str, default: Option<&str>) -> String {
+    match try_with_lang(lang, code, default) {
         Ok(highlighted) => highlighted,
         Err(err) => {
             if err.is::<LimitsExceeded>() {
@@ -92,23 +98,29 @@ mod tests {
 
     #[test]
     fn custom_filetypes() {
-        let toml = select_syntax(Some("toml"), "");
+        let toml = select_syntax(Some("toml"), "", None);
 
-        assert_eq!(select_syntax(Some("Cargo.toml.orig"), "").name, toml.name);
-        assert_eq!(select_syntax(Some("Cargo.lock"), "").name, toml.name);
+        assert_eq!(
+            select_syntax(Some("Cargo.toml.orig"), "", None).name,
+            toml.name
+        );
+        assert_eq!(select_syntax(Some("Cargo.lock"), "", None).name, toml.name);
     }
 
     #[test]
     fn dotfile_with_extension() {
-        let toml = select_syntax(Some("toml"), "");
+        let toml = select_syntax(Some("toml"), "", None);
 
-        assert_eq!(select_syntax(Some(".rustfmt.toml"), "").name, toml.name);
+        assert_eq!(
+            select_syntax(Some(".rustfmt.toml"), "", None).name,
+            toml.name
+        );
     }
 
     #[test]
     fn limits() {
         let is_limited = |s: String| {
-            try_with_lang(Some("toml"), &s)
+            try_with_lang(Some("toml"), &s, None)
                 .unwrap_err()
                 .is::<LimitsExceeded>()
         };
@@ -119,7 +131,7 @@ mod tests {
     #[test]
     fn limited_escaped() {
         let text = "<p>\n".to_string() + "aa".repeat(PER_LINE_BYTE_LENGTH_LIMIT).as_str();
-        let highlighted = with_lang(Some("toml"), &text);
+        let highlighted = with_lang(Some("toml"), &text, None);
         assert!(highlighted.starts_with("&lt;p&gt;\n"));
     }
 }

src/web/markdown.rs

@@ -5,9 +5,9 @@ use comrak::{
 use std::collections::HashMap;
 
 #[derive(Debug)]
-struct CodeAdapter<F>(F);
+struct CodeAdapter<F>(F, Option<&'static str>);
 
-impl<F: Fn(Option<&str>, &str) -> String + Send + Sync> SyntaxHighlighterAdapter
+impl<F: Fn(Option<&str>, &str, Option<&str>) -> String + Send + Sync> SyntaxHighlighterAdapter
     for CodeAdapter<F>
 {
     fn write_highlighted(
@@ -19,7 +19,7 @@ impl<F: Fn(Option<&str>, &str) -> String + Send + Sync> SyntaxHighlighterAdapter
         // comrak does not treat `,` as an info-string delimiter, so we do that here
         // TODO: https://github.com/kivikakk/comrak/issues/246
         let lang = lang.and_then(|lang| lang.split(',').next());
-        write!(output, "{}", (self.0)(lang, code))
+        write!(output, "{}", (self.0)(lang, code, self.1))
     }
 
     fn write_pre_tag(
@@ -67,9 +67,10 @@ fn write_opening_tag(
 
 fn render_with_highlighter(
     text: &str,
-    highlighter: impl Fn(Option<&str>, &str) -> String + Send + Sync,
+    default_syntax: Option<&'static str>,
+    highlighter: impl Fn(Option<&str>, &str, Option<&str>) -> String + Send + Sync,
 ) -> String {
-    let code_adapter = CodeAdapter(highlighter);
+    let code_adapter = CodeAdapter(highlighter, default_syntax);
 
     comrak::markdown_to_html_with_plugins(
         text,
@@ -95,7 +96,11 @@ fn render_with_highlighter(
 
 /// Wrapper around the Markdown parser and renderer to render markdown
 pub fn render(text: &str) -> String {
-    render_with_highlighter(text, highlight::with_lang)
+    render_with_highlighter(text, None, highlight::with_lang)
+}
+
+pub fn render_with_default(text: &str, default: &'static str) -> String {
+    render_with_highlighter(text, Some(default), highlight::with_lang)
 }
 
 #[cfg(test)]
@@ -118,7 +123,8 @@ mod test {
                 ignore::spaces();
                 ```
             "},
-            |lang, code| {
+            None,
+            |lang, code, _| {
                 let mut highlighted = highlighted.lock().unwrap();
                 highlighted.push((lang.map(str::to_owned), code.to_owned()));
                 code.to_owned()

src/web/page/templates.rs

@@ -201,7 +201,8 @@ pub mod filters {
     }
 
     pub fn highlight(code: impl std::fmt::Display, lang: &str) -> rinja::Result<Safe<String>> {
-        let highlighted_code = crate::web::highlight::with_lang(Some(lang), &code.to_string());
+        let highlighted_code =
+            crate::web::highlight::with_lang(Some(lang), &code.to_string(), None);
         Ok(Safe(format!(
             "<pre><code>{}</code></pre>",
             highlighted_code

templates/crate/details.html

@@ -194,7 +194,7 @@
 
                 {# If there's a readme, display it #}
                 {%- if let Some(readme) = readme -%}
-                    {{ crate::web::markdown::render(readme)|safe }}
+                    {{ crate::web::markdown::render_with_default(readme, "rust")|safe }}
 
                 {# If there's not a readme then attempt to display the long description #}
                 {%- elif let Some(rustdoc) = rustdoc -%}