Clean up handling of style files in rustdoc

Disable all themes other than `light.css` to prevent rule conflicts

src/librustdoc/config.rs

@@ -20,6 +20,7 @@ use crate::core::new_handler;
 use crate::externalfiles::ExternalHtml;
 use crate::html;
 use crate::html::markdown::IdMap;
+use crate::html::render::StylePath;
 use crate::html::static_files;
 use crate::opts;
 use crate::passes::{self, Condition, DefaultPassOption};
@@ -207,7 +208,7 @@ pub struct RenderOptions {
     pub sort_modules_alphabetically: bool,
     /// List of themes to extend the docs with. Original argument name is included to assist in
     /// displaying errors if it fails a theme check.
-    pub themes: Vec<PathBuf>,
+    pub themes: Vec<StylePath>,
     /// If present, CSS file that contains rules to add to the default CSS.
     pub extension_css: Option<PathBuf>,
     /// A map of crate names to the URL to use instead of querying the crate's `html_root_url`.
@@ -410,7 +411,7 @@ impl Options {
                     ))
                     .emit();
                 }
-                themes.push(theme_file);
+                themes.push(StylePath { path: theme_file, disabled: true });
             }
         }
 

src/librustdoc/html/layout.rs

@@ -3,7 +3,7 @@ use std::path::PathBuf;
 use crate::externalfiles::ExternalHtml;
 use crate::html::escape::Escape;
 use crate::html::format::{Buffer, Print};
-use crate::html::render::ensure_trailing_slash;
+use crate::html::render::{ensure_trailing_slash, StylePath};
 
 #[derive(Clone)]
 pub struct Layout {
@@ -36,7 +36,7 @@ pub fn render<T: Print, S: Print>(
     page: &Page<'_>,
     sidebar: S,
     t: T,
-    themes: &[PathBuf],
+    style_files: &[StylePath],
 ) -> String {
     let static_root_path = page.static_root_path.unwrap_or(page.root_path);
     format!(
@@ -52,10 +52,7 @@ pub fn render<T: Print, S: Print>(
     <link rel=\"stylesheet\" type=\"text/css\" href=\"{static_root_path}normalize{suffix}.css\">\
     <link rel=\"stylesheet\" type=\"text/css\" href=\"{static_root_path}rustdoc{suffix}.css\" \
           id=\"mainThemeStyle\">\
-    {themes}\
+    {style_files}\
-    <link rel=\"stylesheet\" type=\"text/css\" href=\"{static_root_path}dark{suffix}.css\">\
-    <link rel=\"stylesheet\" type=\"text/css\" href=\"{static_root_path}light{suffix}.css\" \
-          id=\"themeStyle\">\
     <script src=\"{static_root_path}storage{suffix}.js\"></script>\
     <noscript><link rel=\"stylesheet\" href=\"{static_root_path}noscript{suffix}.css\"></noscript>\
     {css_extension}\
@@ -172,13 +169,19 @@ pub fn render<T: Print, S: Print>(
         after_content = layout.external_html.after_content,
         sidebar = Buffer::html().to_display(sidebar),
         krate = layout.krate,
-        themes = themes
+        style_files = style_files
             .iter()
-            .filter_map(|t| t.file_stem())
+            .filter_map(|t| {
-            .filter_map(|t| t.to_str())
+                if let Some(stem) = t.path.file_stem() { Some((stem, t.disabled)) } else { None }
+            })
+            .filter_map(|t| {
+                if let Some(path) = t.0.to_str() { Some((path, t.1)) } else { None }
+            })
             .map(|t| format!(
-                r#"<link rel="stylesheet" type="text/css" href="{}.css">"#,
+                r#"<link rel="stylesheet" type="text/css" href="{}.css" {} {}>"#,
-                Escape(&format!("{}{}{}", static_root_path, t, page.resource_suffix))
+                Escape(&format!("{}{}{}", static_root_path, t.0, page.resource_suffix)),
+                if t.1 { "disabled" } else { "" },
+                if t.0 == "light" { "id=\"themeStyle\"" } else { "" }
             ))
             .collect::<String>(),
         suffix = page.resource_suffix,

src/librustdoc/html/render.rs

@@ -187,8 +187,8 @@ crate struct SharedContext {
     /// This flag indicates whether listings of modules (in the side bar and documentation itself)
     /// should be ordered alphabetically or in order of appearance (in the source code).
     pub sort_modules_alphabetically: bool,
-    /// Additional themes to be added to the generated docs.
+    /// Additional CSS files to be added to the generated docs.
-    pub themes: Vec<PathBuf>,
+    pub style_files: Vec<StylePath>,
     /// Suffix to be added on resource files (if suffix is "-v2" then "light.css" becomes
     /// "light-v2.css").
     pub resource_suffix: String,
@@ -417,6 +417,14 @@ impl Serialize for TypeWithKind {
     }
 }
 
+#[derive(Debug, Clone)]
+pub struct StylePath {
+    /// The path to the theme
+    pub path: PathBuf,
+    /// What the `disabled` attribute should be set to in the HTML tag
+    pub disabled: bool,
+}
+
 thread_local!(static CACHE_KEY: RefCell<Arc<Cache>> = Default::default());
 thread_local!(pub static CURRENT_DEPTH: Cell<usize> = Cell::new(0));
 
@@ -460,7 +468,7 @@ pub fn run(
         id_map,
         playground_url,
         sort_modules_alphabetically,
-        themes,
+        themes: style_files,
         extension_css,
         extern_html_root_urls,
         resource_suffix,
@@ -530,7 +538,7 @@ pub fn run(
         layout,
         created_dirs: Default::default(),
         sort_modules_alphabetically,
-        themes,
+        style_files,
         resource_suffix,
         static_root_path,
         fs: DocFS::new(&errors),
@@ -539,6 +547,18 @@ pub fn run(
         playground,
     };
 
+    // Add the default themes to the `Vec` of stylepaths
+    //
+    // Note that these must be added before `sources::render` is called
+    // so that the resulting source pages are styled
+    //
+    // `light.css` is not disabled because it is the stylesheet that stays loaded
+    // by the browser as the theme stylesheet. The theme system (hackily) works by
+    // changing the href to this stylesheet. All other themes are disabled to
+    // prevent rule conflicts
+    scx.style_files.push(StylePath { path: PathBuf::from("light.css"), disabled: false });
+    scx.style_files.push(StylePath { path: PathBuf::from("dark.css"), disabled: true });
+
     let dst = output;
     scx.ensure_dir(&dst)?;
     krate = sources::render(&dst, &mut scx, krate)?;
@@ -615,11 +635,34 @@ fn write_shared(
     // then we'll run over the "official" styles.
     let mut themes: FxHashSet<String> = FxHashSet::default();
 
-    for entry in &cx.shared.themes {
+    for entry in &cx.shared.style_files {
-        let content = try_err!(fs::read(&entry), &entry);
+        let theme = try_none!(try_none!(entry.path.file_stem(), &entry.path).to_str(), &entry.path);
-        let theme = try_none!(try_none!(entry.file_stem(), &entry).to_str(), &entry);
+        let extension =
-        let extension = try_none!(try_none!(entry.extension(), &entry).to_str(), &entry);
+            try_none!(try_none!(entry.path.extension(), &entry.path).to_str(), &entry.path);
-        cx.shared.fs.write(cx.path(&format!("{}.{}", theme, extension)), content.as_slice())?;
+
+        // Handle the official themes
+        match theme {
+            "light" => write_minify(
+                &cx.shared.fs,
+                cx.path("light.css"),
+                static_files::themes::LIGHT,
+                options.enable_minification,
+            )?,
+            "dark" => write_minify(
+                &cx.shared.fs,
+                cx.path("dark.css"),
+                static_files::themes::DARK,
+                options.enable_minification,
+            )?,
+            _ => {
+                // Handle added third-party themes
+                let content = try_err!(fs::read(&entry.path), &entry.path);
+                cx.shared
+                    .fs
+                    .write(cx.path(&format!("{}.{}", theme, extension)), content.as_slice())?;
+            }
+        };
+
         themes.insert(theme.to_owned());
     }
 
@@ -633,20 +676,6 @@ fn write_shared(
     write(cx.path("brush.svg"), static_files::BRUSH_SVG)?;
     write(cx.path("wheel.svg"), static_files::WHEEL_SVG)?;
     write(cx.path("down-arrow.svg"), static_files::DOWN_ARROW_SVG)?;
-    write_minify(
-        &cx.shared.fs,
-        cx.path("light.css"),
-        static_files::themes::LIGHT,
-        options.enable_minification,
-    )?;
-    themes.insert("light".to_owned());
-    write_minify(
-        &cx.shared.fs,
-        cx.path("dark.css"),
-        static_files::themes::DARK,
-        options.enable_minification,
-    )?;
-    themes.insert("dark".to_owned());
 
     let mut themes: Vec<&String> = themes.iter().collect();
     themes.sort();
@@ -957,7 +986,7 @@ themePicker.onblur = handleThemeButtonsBlur;
                     })
                     .collect::<String>()
             );
-            let v = layout::render(&cx.shared.layout, &page, "", content, &cx.shared.themes);
+            let v = layout::render(&cx.shared.layout, &page, "", content, &cx.shared.style_files);
             cx.shared.fs.write(&dst, v.as_bytes())?;
         }
     }
@@ -1375,7 +1404,7 @@ impl Context {
             &page,
             sidebar,
             |buf: &mut Buffer| all.print(buf),
-            &self.shared.themes,
+            &self.shared.style_files,
         );
         self.shared.fs.write(&final_file, v.as_bytes())?;
 
@@ -1384,9 +1413,9 @@ impl Context {
         page.description = "Settings of Rustdoc";
         page.root_path = "./";
 
-        let mut themes = self.shared.themes.clone();
+        let mut style_files = self.shared.style_files.clone();
         let sidebar = "<p class='location'>Settings</p><div class='sidebar-elems'></div>";
-        themes.push(PathBuf::from("settings.css"));
+        style_files.push(StylePath { path: PathBuf::from("settings.css"), disabled: false });
         let v = layout::render(
             &self.shared.layout,
             &page,
@@ -1395,7 +1424,7 @@ impl Context {
                 self.shared.static_root_path.as_deref().unwrap_or("./"),
                 &self.shared.resource_suffix,
             ),
-            &themes,
+            &style_files,
         );
         self.shared.fs.write(&settings_file, v.as_bytes())?;
 
@@ -1457,7 +1486,7 @@ impl Context {
                 &page,
                 |buf: &mut _| print_sidebar(self, it, buf),
                 |buf: &mut _| print_item(self, it, buf),
-                &self.shared.themes,
+                &self.shared.style_files,
             )
         } else {
             let mut url = self.root_path();

src/librustdoc/html/sources.rs

@@ -123,7 +123,7 @@ impl<'a> SourceCollector<'a> {
             &page,
             "",
             |buf: &mut _| print_src(buf, &contents),
-            &self.scx.themes,
+            &self.scx.style_files,
         );
         self.scx.fs.write(&cur, v.as_bytes())?;
         self.scx.local_sources.insert(p, href);