Rollup merge of #77213 - ijackson:wip-rustdoc-settings, r=jyn514,GuillaumeGomez

rustdoc options to set default theme (and other settings)

Hi.  This is the MR I promised in #77024

It is a little more general than I envisaged there.  Once I had found the settings-handling machinery it seemed foolish to add this feature just for the theme.

Closes #77024

8 files changed, 109 insertions, 25 deletions

diff --git a/src/librustdoc/config.rs b/src/librustdoc/config.rs
index a5fc0757816..02885f51936 100644
--- a/src/librustdoc/config.rs
+++ b/src/librustdoc/config.rs
@@ -1,4 +1,4 @@
-use std::collections::BTreeMap;
+use std::collections::{BTreeMap, HashMap};
 use std::convert::TryFrom;
 use std::ffi::OsStr;
 use std::fmt;
@@ -216,6 +216,9 @@ pub struct RenderOptions {
     pub extension_css: Option<PathBuf>,
     /// A map of crate names to the URL to use instead of querying the crate's `html_root_url`.
     pub extern_html_root_urls: BTreeMap<String, String>,
+    /// A map of the default settings (values are as for DOM storage API). Keys should lack the
+    /// `rustdoc-` prefix.
+    pub default_settings: HashMap<String, String>,
     /// If present, suffix added to CSS/JavaScript files when referencing them in generated pages.
     pub resource_suffix: String,
     /// Whether to run the static CSS/JavaScript through a minifier when outputting them. `true` by
@@ -374,6 +377,32 @@ impl Options {
             }
         };
 
+        let default_settings: Vec<Vec<(String, String)>> = vec![
+            matches
+                .opt_str("default-theme")
+                .iter()
+                .map(|theme| {
+                    vec![
+                        ("use-system-theme".to_string(), "false".to_string()),
+                        ("theme".to_string(), theme.to_string()),
+                    ]
+                })
+                .flatten()
+                .collect(),
+            matches
+                .opt_strs("default-setting")
+                .iter()
+                .map(|s| {
+                    let mut kv = s.splitn(2, '=');
+                    // never panics because `splitn` always returns at least one element
+                    let k = kv.next().unwrap().to_string();
+                    let v = kv.next().unwrap_or("true").to_string();
+                    (k, v)
+                })
+                .collect(),
+        ];
+        let default_settings = default_settings.into_iter().flatten().collect();
+
         let test_args = matches.opt_strs("test-args");
         let test_args: Vec<String> =
             test_args.iter().flat_map(|s| s.split_whitespace()).map(|s| s.to_string()).collect();
@@ -596,6 +625,7 @@ impl Options {
                 themes,
                 extension_css,
                 extern_html_root_urls,
+                default_settings,
                 resource_suffix,
                 enable_minification,
                 enable_index_page,
diff --git a/src/librustdoc/html/layout.rs b/src/librustdoc/html/layout.rs
index 7239b3c5ba2..b089bcb0862 100644
--- a/src/librustdoc/html/layout.rs
+++ b/src/librustdoc/html/layout.rs
@@ -1,3 +1,4 @@
+use std::collections::HashMap;
 use std::path::PathBuf;
 
 use crate::externalfiles::ExternalHtml;
@@ -10,6 +11,7 @@ pub struct Layout {
     pub logo: String,
     pub favicon: String,
     pub external_html: ExternalHtml,
+    pub default_settings: HashMap<String, String>,
     pub krate: String,
     /// The given user css file which allow to customize the generated
     /// documentation theme.
@@ -53,6 +55,7 @@ pub fn render<T: Print, S: Print>(
     <link rel=\"stylesheet\" type=\"text/css\" href=\"{static_root_path}rustdoc{suffix}.css\" \
           id=\"mainThemeStyle\">\
     {style_files}\
+    <script id=\"default-settings\"{default_settings}></script>\
     <script src=\"{static_root_path}storage{suffix}.js\"></script>\
     <noscript><link rel=\"stylesheet\" href=\"{static_root_path}noscript{suffix}.css\"></noscript>\
     {css_extension}\
@@ -172,6 +175,11 @@ pub fn render<T: Print, S: Print>(
         after_content = layout.external_html.after_content,
         sidebar = Buffer::html().to_display(sidebar),
         krate = layout.krate,
+        default_settings = layout
+            .default_settings
+            .iter()
+            .map(|(k, v)| format!(r#" data-{}="{}""#, k.replace('-', "_"), Escape(v)))
+            .collect::<String>(),
         style_files = style_files
             .iter()
             .filter_map(|t| {
diff --git a/src/librustdoc/html/markdown.rs b/src/librustdoc/html/markdown.rs
index 2fd06d7e573..ca8b811681c 100644
--- a/src/librustdoc/html/markdown.rs
+++ b/src/librustdoc/html/markdown.rs
@@ -1228,6 +1228,7 @@ fn init_id_map() -> FxHashMap<String, usize> {
     map.insert("render-detail".to_owned(), 1);
     map.insert("toggle-all-docs".to_owned(), 1);
     map.insert("all-types".to_owned(), 1);
+    map.insert("default-settings".to_owned(), 1);
     // This is the list of IDs used by rustdoc sections.
     map.insert("fields".to_owned(), 1);
     map.insert("variants".to_owned(), 1);
diff --git a/src/librustdoc/html/render/mod.rs b/src/librustdoc/html/render/mod.rs
index 1726093c6fa..0621eafd913 100644
--- a/src/librustdoc/html/render/mod.rs
+++ b/src/librustdoc/html/render/mod.rs
@@ -392,6 +392,7 @@ impl FormatRenderer for Context {
             playground_url,
             sort_modules_alphabetically,
             themes: style_files,
+            default_settings,
             extension_css,
             resource_suffix,
             static_root_path,
@@ -415,6 +416,7 @@ impl FormatRenderer for Context {
             logo: String::new(),
             favicon: String::new(),
             external_html,
+            default_settings,
             krate: krate.name.clone(),
             css_file_extension: extension_css,
             generate_search_filter,
diff --git a/src/librustdoc/html/static/main.js b/src/librustdoc/html/static/main.js
index e382e5aa234..28bd1ba5247 100644
--- a/src/librustdoc/html/static/main.js
+++ b/src/librustdoc/html/static/main.js
@@ -89,7 +89,7 @@ function defocusSearchBar() {
                      "derive",
                      "traitalias"];
 
-    var disableShortcuts = getCurrentValue("rustdoc-disable-shortcuts") === "true";
+    var disableShortcuts = getSettingValue("disable-shortcuts") === "true";
     var search_input = getSearchInput();
     var searchTimeout = null;
     var toggleAllDocsId = "toggle-all-docs";
@@ -1580,7 +1580,7 @@ function defocusSearchBar() {
         function showResults(results) {
             var search = getSearchElement();
             if (results.others.length === 1
-                && getCurrentValue("rustdoc-go-to-only-result") === "true"
+                && getSettingValue("go-to-only-result") === "true"
                 // By default, the search DOM element is "empty" (meaning it has no children not
                 // text content). Once a search has been run, it won't be empty, even if you press
                 // ESC or empty the search input (which also "cancels" the search).
@@ -2296,7 +2296,7 @@ function defocusSearchBar() {
     function autoCollapse(pageId, collapse) {
         if (collapse) {
             toggleAllDocs(pageId, true);
-        } else if (getCurrentValue("rustdoc-auto-hide-trait-implementations") !== "false") {
+        } else if (getSettingValue("auto-hide-trait-implementations") !== "false") {
             var impl_list = document.getElementById("trait-implementations-list");
 
             if (impl_list !== null) {
@@ -2370,8 +2370,8 @@ function defocusSearchBar() {
         }
 
         var toggle = createSimpleToggle(false);
-        var hideMethodDocs = getCurrentValue("rustdoc-auto-hide-method-docs") === "true";
-        var hideImplementors = getCurrentValue("rustdoc-auto-collapse-implementors") !== "false";
+        var hideMethodDocs = getSettingValue("auto-hide-method-docs") === "true";
+        var hideImplementors = getSettingValue("auto-collapse-implementors") !== "false";
         var pageId = getPageId();
 
         var func = function(e) {
@@ -2487,7 +2487,7 @@ function defocusSearchBar() {
                 });
             }
         }
-        var showItemDeclarations = getCurrentValue("rustdoc-auto-hide-" + className);
+        var showItemDeclarations = getSettingValue("auto-hide-" + className);
         if (showItemDeclarations === null) {
             if (className === "enum" || className === "macro") {
                 showItemDeclarations = "false";
@@ -2495,7 +2495,7 @@ function defocusSearchBar() {
                 showItemDeclarations = "true";
             } else {
                 // In case we found an unknown type, we just use the "parent" value.
-                showItemDeclarations = getCurrentValue("rustdoc-auto-hide-declarations");
+                showItemDeclarations = getSettingValue("auto-hide-declarations");
             }
         }
         showItemDeclarations = showItemDeclarations === "false";
@@ -2569,7 +2569,7 @@ function defocusSearchBar() {
         onEachLazy(document.getElementsByClassName("sub-variant"), buildToggleWrapper);
         var pageId = getPageId();
 
-        autoCollapse(pageId, getCurrentValue("rustdoc-collapse") === "true");
+        autoCollapse(pageId, getSettingValue("collapse") === "true");
 
         if (pageId !== null) {
             expandSection(pageId);
@@ -2592,7 +2592,7 @@ function defocusSearchBar() {
     (function() {
         // To avoid checking on "rustdoc-item-attributes" value on every loop...
         var itemAttributesFunc = function() {};
-        if (getCurrentValue("rustdoc-auto-hide-attributes") !== "false") {
+        if (getSettingValue("auto-hide-attributes") !== "false") {
             itemAttributesFunc = function(x) {
                 collapseDocs(x.previousSibling.childNodes[0], "toggle");
             };
@@ -2611,7 +2611,7 @@ function defocusSearchBar() {
     (function() {
         // To avoid checking on "rustdoc-line-numbers" value on every loop...
         var lineNumbersFunc = function() {};
-        if (getCurrentValue("rustdoc-line-numbers") === "true") {
+        if (getSettingValue("line-numbers") === "true") {
             lineNumbersFunc = function(x) {
                 var count = x.textContent.split("\n").length;
                 var elems = [];
@@ -2768,7 +2768,7 @@ function defocusSearchBar() {
             }
             return 0;
         });
-        var savedCrate = getCurrentValue("rustdoc-saved-filter-crate");
+        var savedCrate = getSettingValue("saved-filter-crate");
         for (var i = 0; i < crates_text.length; ++i) {
             var option = document.createElement("option");
             option.value = crates_text[i];
diff --git a/src/librustdoc/html/static/settings.js b/src/librustdoc/html/static/settings.js
index 00a01ac30bc..da3378ccf0d 100644
--- a/src/librustdoc/html/static/settings.js
+++ b/src/librustdoc/html/static/settings.js
@@ -14,10 +14,6 @@
         }
     }
 
-    function getSettingValue(settingName) {
-        return getCurrentValue("rustdoc-" + settingName);
-    }
-
     function setEvents() {
         var elems = {
             toggles: document.getElementsByClassName("slider"),
diff --git a/src/librustdoc/html/static/storage.js b/src/librustdoc/html/static/storage.js
index ef734f260af..d081781f14b 100644
--- a/src/librustdoc/html/static/storage.js
+++ b/src/librustdoc/html/static/storage.js
@@ -1,10 +1,37 @@
 // From rust:
-/* global resourcesSuffix */
+/* global resourcesSuffix, getSettingValue */
 
 var darkThemes = ["dark", "ayu"];
 var currentTheme = document.getElementById("themeStyle");
 var mainTheme = document.getElementById("mainThemeStyle");
-var localStoredTheme = getCurrentValue("rustdoc-theme");
+
+var settingsDataset = (function () {
+    var settingsElement = document.getElementById("default-settings");
+    if (settingsElement === null) {
+        return null;
+    }
+    var dataset = settingsElement.dataset;
+    if (dataset === undefined) {
+        return null;
+    }
+    return dataset;
+})();
+
+function getSettingValue(settingName) {
+    var current = getCurrentValue('rustdoc-' + settingName);
+    if (current !== null) {
+        return current;
+    }
+    if (settingsDataset !== null) {
+        var def = settingsDataset[settingName.replace(/-/g,'_')];
+        if (def !== undefined) {
+            return def;
+        }
+    }
+    return null;
+}
+
+var localStoredTheme = getSettingValue("theme");
 
 var savedHref = [];
 
@@ -156,9 +183,9 @@ var updateSystemTheme = (function() {
 
     function handlePreferenceChange(mql) {
         // maybe the user has disabled the setting in the meantime!
-        if (getCurrentValue("rustdoc-use-system-theme") !== "false") {
-            var lightTheme = getCurrentValue("rustdoc-preferred-light-theme") || "light";
-            var darkTheme = getCurrentValue("rustdoc-preferred-dark-theme") || "dark";
+        if (getSettingValue("use-system-theme") !== "false") {
+            var lightTheme = getSettingValue("preferred-light-theme") || "light";
+            var darkTheme = getSettingValue("preferred-dark-theme") || "dark";
 
             if (mql.matches) {
                 // prefers a dark theme
@@ -181,11 +208,11 @@ var updateSystemTheme = (function() {
     };
 })();
 
-if (getCurrentValue("rustdoc-use-system-theme") !== "false" && window.matchMedia) {
+if (getSettingValue("use-system-theme") !== "false" && window.matchMedia) {
     // update the preferred dark theme if the user is already using a dark theme
     // See https://github.com/rust-lang/rust/pull/77809#issuecomment-707875732
-    if (getCurrentValue("rustdoc-use-system-theme") === null
-        && getCurrentValue("rustdoc-preferred-dark-theme") === null
+    if (getSettingValue("use-system-theme") === null
+        && getSettingValue("preferred-dark-theme") === null
         && darkThemes.indexOf(localStoredTheme) >= 0) {
         updateLocalStorage("rustdoc-preferred-dark-theme", localStoredTheme);
     }
@@ -196,7 +223,7 @@ if (getCurrentValue("rustdoc-use-system-theme") !== "false" && window.matchMedia
     switchTheme(
         currentTheme,
         mainTheme,
-        getCurrentValue("rustdoc-theme") || "light",
+        getSettingValue("theme") || "light",
         false
     );
 }
diff --git a/src/librustdoc/lib.rs b/src/librustdoc/lib.rs
index 616f0efcd75..7efbca5c6c3 100644
--- a/src/librustdoc/lib.rs
+++ b/src/librustdoc/lib.rs
@@ -269,6 +269,26 @@ fn opts() -> Vec<RustcOptGroup> {
                 "sort modules by where they appear in the program, rather than alphabetically",
             )
         }),
+        unstable("default-theme", |o| {
+            o.optopt(
+                "",
+                "default-theme",
+                "Set the default theme. THEME should be the theme name, generally lowercase. \
+                 If an unknown default theme is specified, the builtin default is used. \
+                 The set of themes, and the rustdoc built-in default is not stable.",
+                "THEME",
+            )
+        }),
+        unstable("default-setting", |o| {
+            o.optmulti(
+                "",
+                "default-setting",
+                "Default value for a rustdoc setting (used when \"rustdoc-SETTING\" is absent \
+                 from web browser Local Storage). If VALUE is not supplied, \"true\" is used. \
+                 Supported SETTINGs and VALUEs are not documented and not stable.",
+                "SETTING[=VALUE]",
+            )
+        }),
         stable("theme", |o| {
             o.optmulti(
                 "",