Add expand feature for code blocks

Author: GuillaumeGomez

src/librustdoc/html/highlight.rs

@@ -82,8 +82,8 @@ crate fn render_with_highlighting<'a>(
     }
 
     write_header(out, class, extra_content);
-    write_code(out, src, edition, context_info);
-    write_footer(out, playground_button);
+    let expand = write_code(out, src, edition, context_info);
+    write_footer(out, playground_button, expand);
 }
 
 fn write_header(out: &mut Buffer, class: Option<&str>, extra_content: Option<Buffer>) {
@@ -115,46 +115,55 @@ fn write_code(
     src: impl Iterator<Item = Line<'a>>,
     edition: Edition,
     context_info: Option<ContextInfo<'_, '_, '_>>,
-) {
+) -> bool {
     let mut iter = src.peekable();
+    let mut expand = false;
 
     // For each `Line`, we replace DOS backlines with '\n'. This replace allows to fix how the code
     // source with DOS backline characters is displayed.
     while let Some(line) = iter.next() {
-        match line {
+        let (before, text, after) = match line {
             Line::Hidden(text) => {
-                write!(
-                    out,
-                    "<span class=\"hidden\">{}{}</span>",
-                    Escape(&text.replace("\r\n", "\n")),
-                    if iter.peek().is_some() && !text.ends_with('\n') { "\n" } else { "" },
-                );
-            }
-            Line::Shown(text) => {
-                Classifier::new(&text.replace("\r\n", "\n"), edition, context_info.as_ref().map(|c| c.file_span).unwrap_or(DUMMY_SP)).highlight(&mut |highlight| {
-                    match highlight {
-                        Highlight::Token { text, class } => string(out, Escape(text), class),
-                        Highlight::EnterSpan { class } => enter_span(out, class),
-                        Highlight::ExitSpan => exit_span(out),
-                    };
-                });
-                if iter.peek().is_some() && !text.ends_with('\n') {
-                    write!(out, "\n");
-                }
+                expand = true;
+                ("<span class=\"hidden\">", text.replace("\r\n", "\n"), "</span>")
             }
+            Line::Shown(text) => ("", text.replace("\r\n", "\n"), ""),
+        };
+        if !before.is_empty() {
+            out.push_str(before);
+        }
+        Classifier::new(
+            &text.replace("\r\n", "\n"),
+            edition,
+            context_info.as_ref().map(|c| c.file_span).unwrap_or(DUMMY_SP),
+        )
+        .highlight(&mut |highlight| {
+            match highlight {
+                Highlight::Token { text, class } => string(out, Escape(text), class, context_info),
+                Highlight::EnterSpan { class } => enter_span(out, class),
+                Highlight::ExitSpan => exit_span(out),
+            };
+        });
+        if iter.peek().is_some() && !text.ends_with('\n') {
+            out.push_str("\n");
+        }
+        if !after.is_empty() {
+            out.push_str(after);
         }
     }
+    expand
 }
 
-fn write_footer(out: &mut Buffer, playground_button: Option<&str>) {
+fn write_footer(out: &mut Buffer, playground_button: Option<&str>, expand: bool) {
     writeln!(
         out,
         "</code></pre>\
          <div class=\"code-buttons\">\
-             {}<button class=\"copy-code\" onclick=\"copyCode(this)\"></button>\
+             {}{}<button class=\"copy-code\" onclick=\"copyCode(this)\"></button>\
          </div>\
         </div>",
-        playground_button.unwrap_or_default()
+        playground_button.unwrap_or_default(),
+        if expand { "<button class=\"expand\" onclick=\"expandCode(this)\"></button>" } else { "" },
     );
 }
 

src/librustdoc/html/render/write_shared.rs

@@ -179,6 +179,7 @@ pub(super) fn write_shared(
         cx.write_shared(SharedResource::InvocationSpecific { basename: p }, content, &options.emit)
     };
 
+    // This is required because the name of the image changes based on the current toolchain.
     fn add_background_image_to_css(
         cx: &Context<'_>,
         css: &mut String,
@@ -218,6 +219,12 @@ pub(super) fn write_shared(
 
     // Add all the static files. These may already exist, but we just
     // overwrite them anyway to make sure that they're fresh and up-to-date.
+    let mut rustdoc_css = static_files::RUSTDOC_CSS.to_owned();
+    add_background_image_to_css(cx, &mut rustdoc_css, ".copy-code", "clipboard.svg");
+    add_background_image_to_css(cx, &mut rustdoc_css, ".expand", "eye.svg");
+    add_background_image_to_css(cx, &mut rustdoc_css, ".collapse", "eye-slash.svg");
+    write_minify("rustdoc.css", rustdoc_css, cx, options)?;
+
     write_minify("settings.css", static_files::SETTINGS_CSS, cx, options)?;
     write_minify("noscript.css", static_files::NOSCRIPT_CSS, cx, options)?;
 
@@ -259,6 +266,8 @@ pub(super) fn write_shared(
     write_toolchain("down-arrow.svg", static_files::DOWN_ARROW_SVG)?;
     write_toolchain("toggle-minus.svg", static_files::TOGGLE_MINUS_PNG)?;
     write_toolchain("toggle-plus.svg", static_files::TOGGLE_PLUS_PNG)?;
+    write_toolchain("eye.svg", static_files::EXPAND_SVG)?;
+    write_toolchain("eye-slash.svg", static_files::COLLAPSE_SVG)?;
 
     let mut themes: Vec<&String> = themes.iter().collect();
     themes.sort();

src/librustdoc/html/static/css/noscript.css

@@ -9,7 +9,7 @@ rules.
 	margin-left: 0 !important;
 }
 
-#copy-path, .copy-code {
+#copy-path, .copy-code, .expand, .collapse {
 	/* It requires JS to work so no need to display it in this case. */
 	display: none;
 }

src/librustdoc/html/static/css/rustdoc.css

@@ -1056,8 +1056,7 @@ a.test-arrow {
 a.test-arrow:hover{
 	text-decoration: none;
 }
-.copy-code {
-	background-image: url(clipboard1.55.0.svg);
+.copy-code, .expand, .collapse {
 	width: 21px;
 	background-size: contain;
 	background-color: transparent;

src/librustdoc/html/static/css/themes/ayu.css

@@ -336,11 +336,11 @@ a.test-arrow:hover {
 	color: #c5c5c5;
 }
 
-.copy-code {
+.copy-code, .expand, .collapse {
 	filter: invert(70%);
 	color: #fff;
 }
-.copy-code:hover {
+.copy-code:hover, .expand:hover, .collapse:hover {
 	filter: invert(100%);
 }
 

src/librustdoc/html/static/css/themes/dark.css

@@ -190,11 +190,11 @@ body.source .example-wrap pre.rust a {
 a.test-arrow {
 	color: #dedede;
 }
-.copy-code {
+.copy-code, .expand, .collapse {
 	filter: invert(50%);
 	color: #999;
 }
-.copy-code:hover {
+.copy-code:hover, .expand:hover, .collapse:hover {
 	filter: invert(65%);
 }
 

src/librustdoc/html/static/css/themes/light.css

@@ -185,11 +185,11 @@ body.source .example-wrap pre.rust a {
 a.test-arrow {
 	color: #f5f5f5;
 }
-.copy-code {
+.copy-code, .expand, .collapse {
 	filter: invert(50%);
 	color: #999;
 }
-.copy-code:hover {
+.copy-code:hover, .expand:hover, .collapse:hover {
 	filter: invert(35%);
 }