Add "copy to clipboard" button for all codeblocks

Author: GuillaumeGomez

src/librustdoc/html/highlight.rs

@@ -9,15 +9,17 @@ use crate::clean::PrimitiveType;
 use crate::html::escape::Escape;
 use crate::html::render::Context;
 
-use std::fmt::{Display, Write};
-use std::iter::Peekable;
+use std::borrow::Cow;
+use std::fmt::{Debug, Display, Write};
+use std::iter::{once, Peekable};
 
 use rustc_lexer::{LiteralKind, TokenKind};
 use rustc_span::edition::Edition;
 use rustc_span::symbol::Symbol;
 use rustc_span::{BytePos, Span, DUMMY_SP};
 
 use super::format::{self, Buffer};
+use super::markdown::Line;
 use super::render::LinkFromSrc;
 
 /// This type is needed in case we want to render links on items to allow to go to their definition.
@@ -31,7 +33,7 @@ crate struct ContextInfo<'a, 'b, 'c> {
 }
 
 /// Highlights `src`, returning the HTML output.
-crate fn render_with_highlighting(
+crate fn render_source_with_highlighting(
     src: &str,
     out: &mut Buffer,
     class: Option<&str>,
@@ -41,7 +43,31 @@ crate fn render_with_highlighting(
     extra_content: Option<Buffer>,
     context_info: Option<ContextInfo<'_, '_, '_>>,
 ) {
-    debug!("highlighting: ================\n{}\n==============", src);
+    render_with_highlighting(
+        once(Line::Shown(Cow::Borrowed(src))),
+        out,
+        class,
+        playground_button,
+        tooltip,
+        edition,
+        extra_content,
+        context_info,
+    )
+}
+
+/// Highlights `src` containing potential hidden lines, returning the HTML output. If you don't have
+/// hidden lines, use [`render_source_with_highlighting`] instead.
+crate fn render_with_highlighting<'a>(
+    src: impl Iterator<Item = Line<'a>> + Debug,
+    out: &mut Buffer,
+    class: Option<&str>,
+    playground_button: Option<&str>,
+    tooltip: Option<(Option<Edition>, &str)>,
+    edition: Edition,
+    extra_content: Option<Buffer>,
+    context_info: Option<ContextInfo<'_, '_, '_>>,
+) {
+    debug!("highlighting: ================\n{:?}\n==============", src);
     if let Some((edition_info, class)) = tooltip {
         write!(
             out,
@@ -56,7 +82,7 @@ crate fn render_with_highlighting(
     }
 
     write_header(out, class, extra_content);
-    write_code(out, &src, edition, context_info);
+    write_code(out, src, edition, context_info);
     write_footer(out, playground_button);
 }
 
@@ -86,24 +112,50 @@ fn write_header(out: &mut Buffer, class: Option<&str>, extra_content: Option<Buf
 /// More explanations about spans and how we use them here are provided in the
 fn write_code(
     out: &mut Buffer,
-    src: &str,
+    src: impl Iterator<Item = Line<'a>>,
     edition: Edition,
     context_info: Option<ContextInfo<'_, '_, '_>>,
 ) {
-    // This replace allows to fix how the code source with DOS backline characters is displayed.
-    let src = src.replace("\r\n", "\n");
-    Classifier::new(&src, 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),
-            };
-        });
+    let mut iter = src.peekable();
+
+    // 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 {
+            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");
+                }
+            }
+        }
+    }
 }
 
 fn write_footer(out: &mut Buffer, playground_button: Option<&str>) {
-    writeln!(out, "</code></pre>{}</div>", playground_button.unwrap_or_default());
+    writeln!(
+        out,
+        "</code></pre>\
+         <div class=\"code-buttons\">\
+             {}<button class=\"copy-code\" onclick=\"copyCode(this)\"></button>\
+         </div>\
+        </div>",
+        playground_button.unwrap_or_default()
+    );
 }
 
 /// How a span of text is classified. Mostly corresponds to token kinds.

src/librustdoc/html/highlight/tests.rs

@@ -1,9 +1,13 @@
 use super::write_code;
 use crate::html::format::Buffer;
+use crate::html::markdown::Line;
 use expect_test::expect_file;
 use rustc_span::create_default_session_globals_then;
 use rustc_span::edition::Edition;
 
+use std::borrow::Cow;
+use std::iter::once;
+
 const STYLE: &str = r#"
 <style>
 .kw { color: #8959A8; }
@@ -20,6 +24,7 @@ const STYLE: &str = r#"
 fn test_html_highlighting() {
     create_default_session_globals_then(|| {
         let src = include_str!("fixtures/sample.rs");
+        let src = once(Line::Shown(Cow::Borrowed(src)));
         let html = {
             let mut out = Buffer::new();
             write_code(&mut out, src, Edition::Edition2018, None);
@@ -35,6 +40,7 @@ fn test_dos_backline() {
         let src = "pub fn foo() {\r\n\
     println!(\"foo\");\r\n\
 }\r\n";
+        let src = once(Line::Shown(Cow::Borrowed(src)));
         let mut html = Buffer::new();
         write_code(&mut html, src, Edition::Edition2018, None);
         expect_file!["fixtures/dos_line.html"].assert_eq(&html.into_inner());

src/librustdoc/html/markdown.rs

@@ -123,20 +123,14 @@ impl ErrorCodes {
 /// Controls whether a line will be hidden or shown in HTML output.
 ///
 /// All lines are used in documentation tests.
-enum Line<'a> {
+#[derive(Debug)]
+crate enum Line<'a> {
     Hidden(&'a str),
     Shown(Cow<'a, str>),
 }
 
 impl<'a> Line<'a> {
-    fn for_html(self) -> Option<Cow<'a, str>> {
-        match self {
-            Line::Shown(l) => Some(l),
-            Line::Hidden(_) => None,
-        }
-    }
-
-    fn for_code(self) -> Cow<'a, str> {
+    crate fn for_code(self) -> Cow<'a, str> {
         match self {
             Line::Shown(l) => l,
             Line::Hidden(l) => Cow::Borrowed(l),
@@ -229,8 +223,7 @@ impl<'a, I: Iterator<Item = Event<'a>>> Iterator for CodeBlocks<'_, 'a, I> {
                 _ => {}
             }
         }
-        let lines = origtext.lines().filter_map(|l| map_line(l).for_html());
-        let text = lines.collect::<Vec<Cow<'_, str>>>().join("\n");
+        let lines = origtext.lines().map(map_line);
 
         let parse_result = match kind {
             CodeBlockKind::Fenced(ref lang) => {
@@ -243,7 +236,7 @@ impl<'a, I: Iterator<Item = Event<'a>>> Iterator for CodeBlocks<'_, 'a, I> {
                                  <pre class=\"language-{}\"><code>{}</code></pre>\
                              </div>",
                             lang,
-                            Escape(&text),
+                            Escape(&origtext),
                         )
                         .into(),
                     ));
@@ -326,7 +319,7 @@ impl<'a, I: Iterator<Item = Event<'a>>> Iterator for CodeBlocks<'_, 'a, I> {
         let mut s = Buffer::new();
         s.push_str("\n");
         highlight::render_with_highlighting(
-            &text,
+            lines,
             &mut s,
             Some(&format!(
                 "rust-example-rendered{}",

src/librustdoc/html/render/print_item.rs

@@ -1115,7 +1115,7 @@ fn item_enum(w: &mut Buffer, cx: &Context<'_>, it: &clean::Item, e: &clean::Enum
 
 fn item_macro(w: &mut Buffer, cx: &Context<'_>, it: &clean::Item, t: &clean::Macro) {
     wrap_into_docblock(w, |w| {
-        highlight::render_with_highlighting(
+        highlight::render_source_with_highlighting(
             &t.source,
             w,
             Some("macro"),

src/librustdoc/html/sources.rs

@@ -264,7 +264,7 @@ fn print_src(
         writeln!(line_numbers, "<span id=\"{0}\">{0:1$}</span>", i, cols);
     }
     line_numbers.write_str("</pre>");
-    highlight::render_with_highlighting(
+    highlight::render_source_with_highlighting(
         s,
         buf,
         None,

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

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

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

@@ -190,7 +190,8 @@ details.undocumented > summary::before,
 div.impl-items > div:not(.docblock):not(.item-info),
 .content ul.crate a.crate, a.srclink,
 /* This selector is for the items listed in the "all items" page. */
-#main > ul.docblock > li > a {
+#main > ul.docblock > li > a,
+.copy-code {
 	font-family: "Fira Sans", Arial, sans-serif;
 }
 
@@ -240,7 +241,7 @@ details:not(.rustdoc-toggle) summary {
 	margin-bottom: .6em;
 }
 
-code, pre, a.test-arrow, .code-header {
+code, pre, div.code-buttons, .code-header {
 	font-family: "Source Code Pro", monospace;
 }
 .docblock code, .docblock-short code {
@@ -1039,19 +1040,34 @@ pre.rust .question-mark {
 	font-weight: bold;
 }
 
-a.test-arrow {
-	display: inline-block;
+.code-buttons {
+	display: flex;
 	position: absolute;
-	padding: 5px 10px 5px 10px;
-	border-radius: 5px;
-	font-size: 130%;
 	top: 5px;
 	right: 5px;
 	z-index: 1;
+	font-size: 130%;
+}
+a.test-arrow {
+	border-radius: 5px;
+	padding: 5px 10px 5px 10px;
+	display: inline-block;
 }
 a.test-arrow:hover{
 	text-decoration: none;
 }
+.copy-code {
+	background-image: url(clipboard1.55.0.svg);
+	width: 21px;
+	background-size: contain;
+	background-color: transparent;
+	background-repeat: no-repeat;
+	border: 0;
+	background-position: center;
+	border-radius: 4px;
+	cursor: pointer;
+	margin-left: 7px;
+}
 
 .section-header:hover a:before {
 	position: absolute;

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

@@ -331,12 +331,19 @@ a.test-arrow {
 	border-radius: 4px;
 	background-color: rgba(57, 175, 215, 0.09);
 }
-
 a.test-arrow:hover {
 	background-color: rgba(57, 175, 215, 0.368);
 	color: #c5c5c5;
 }
 
+.copy-code {
+	filter: invert(70%);
+	color: #fff;
+}
+.copy-code:hover {
+	filter: invert(100%);
+}
+
 .toggle-label,
 .code-attribute {
 	color: #999;

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

@@ -190,6 +190,13 @@ body.source .example-wrap pre.rust a {
 a.test-arrow {
 	color: #dedede;
 }
+.copy-code {
+	filter: invert(50%);
+	color: #999;
+}
+.copy-code:hover {
+	filter: invert(65%);
+}
 
 details.rustdoc-toggle > summary.hideme > span,
 details.rustdoc-toggle > summary::before,

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

@@ -185,6 +185,13 @@ body.source .example-wrap pre.rust a {
 a.test-arrow {
 	color: #f5f5f5;
 }
+.copy-code {
+	filter: invert(50%);
+	color: #999;
+}
+.copy-code:hover {
+	filter: invert(35%);
+}
 
 details.rustdoc-toggle > summary.hideme > span,
 details.rustdoc-toggle > summary::before,