Add copy button to markdown code blocks

Done mostly in JS because I think it's better not to try getting buttons
past the markup sanitizer.

Author: silverwind

modules/markup/markdown/markdown.go

@@ -107,26 +107,19 @@ func actualRender(ctx *markup.RenderContext, input io.Reader, output io.Writer)
 
 							languageStr := string(language)
 
-							preClasses := []string{}
+							preClasses := []string{"code-block"}
 							if languageStr == "mermaid" {
 								preClasses = append(preClasses, "is-loading")
 							}
 
-							if len(preClasses) > 0 {
-								_, err := w.WriteString(`<pre class="` + strings.Join(preClasses, " ") + `">`)
-								if err != nil {
-									return
-								}
-							} else {
-								_, err := w.WriteString(`<pre>`)
-								if err != nil {
-									return
-								}
+							_, err := w.WriteString(`<pre class="` + strings.Join(preClasses, " ") + `">`)
+							if err != nil {
+								return
 							}
 
 							// include language-x class as part of commonmark spec
-							_, err := w.WriteString(`<code class="chroma language-` + string(language) + `">`)
-							if err != nil {
+							_, err2 := w.WriteString(`<code class="chroma language-` + string(language) + `">`)
+							if err2 != nil {
 								return
 							}
 						} else {

modules/markup/sanitizer.go

@@ -52,6 +52,10 @@ func InitializeSanitizer() {
 
 func createDefaultPolicy() *bluemonday.Policy {
 	policy := bluemonday.UGCPolicy()
+
+	// For JS code copy
+	policy.AllowAttrs("class").Matching(regexp.MustCompile(`^code-block$`)).OnElements("pre")
+
 	// For Chroma markdown plugin
 	policy.AllowAttrs("class").Matching(regexp.MustCompile(`^is-loading$`)).OnElements("pre")
 	policy.AllowAttrs("class").Matching(regexp.MustCompile(`^(chroma )?language-[\w-]+$`)).OnElements("code")

options/locale/locale_en-US.ini

@@ -932,7 +932,7 @@ copy_link_error = Use ⌘C or Ctrl-C to copy
 copy_branch = Copy
 copy_branch_success = Branch name has been copied
 copy_branch_error = Use ⌘C or Ctrl-C to copy
-copied = Copied OK
+copied = Copied
 unwatch = Unwatch
 watch = Watch
 unstar = Unstar

templates/base/head.tmpl

@@ -47,6 +47,11 @@
 			{{end}}
 			mermaidMaxSourceCharacters: {{MermaidMaxSourceCharacters}},
 		};
+
+		window.i18n = {
+			copied: '{{.i18n.Tr "repo.copied"}}',
+			copy_link_error: '{{.i18n.Tr "repo.copy_link_error"}}',
+		};
 	</script>
 	<link rel="icon" href="{{AssetUrlPrefix}}/img/logo.svg" type="image/svg+xml">
 	<link rel="alternate icon" href="{{AssetUrlPrefix}}/img/favicon.png" type="image/png">

web_src/js/features/clipboard.js

@@ -1,21 +1,18 @@
 // For all DOM elements with [data-clipboard-target] or [data-clipboard-text], this copy-to-clipboard will work for them
 
-// TODO: replace these with toast-style notifications
 function onSuccess(btn) {
-  if (!btn.dataset.content) return;
   $(btn).popup('destroy');
   const oldContent = btn.dataset.content;
   btn.dataset.content = btn.dataset.success;
   $(btn).popup('show');
-  btn.dataset.content = oldContent;
+  btn.dataset.content = oldContent || '';
 }
 function onError(btn) {
-  if (!btn.dataset.content) return;
   const oldContent = btn.dataset.content;
   $(btn).popup('destroy');
   btn.dataset.content = btn.dataset.error;
   $(btn).popup('show');
-  btn.dataset.content = oldContent;
+  btn.dataset.content = oldContent || '';
 }
 
 /**

web_src/js/markup/codecopy.js

@@ -0,0 +1,21 @@
+import {svgNode} from '../svg.js';
+const {copied, copy_link_error} = window.i18n;
+
+// els refers to the code elements
+export function renderCodeCopy() {
+  const els = document.querySelectorAll('.markup .code-block code');
+  if (!els?.length) return;
+
+  const button = document.createElement('button');
+  button.classList.add('code-copy', 'ui', 'button');
+  button.setAttribute('data-success', copied);
+  button.setAttribute('data-error', copy_link_error);
+  button.setAttribute('data-variation', 'inverted tiny');
+  button.appendChild(svgNode('octicon-copy'));
+
+  for (const el of els) {
+    const btn = button.cloneNode(true);
+    btn.setAttribute('data-clipboard-text', el.textContent);
+    el.after(btn);
+  }
+}

web_src/js/markup/content.js

@@ -1,9 +1,11 @@
 import {renderMermaid} from './mermaid.js';
+import {renderCodeCopy} from './codecopy.js';
 import {initMarkupTasklist} from './tasklist.js';
 
 // code that runs for all markup content
 export function initMarkupContent() {
-  const _promise = renderMermaid(document.querySelectorAll('code.language-mermaid'));
+  renderMermaid();
+  renderCodeCopy();
 }
 
 // code that only runs for comments

web_src/js/markup/mermaid.js

@@ -8,8 +8,9 @@ function displayError(el, err) {
   el.closest('pre').before(errorNode);
 }
 
-export async function renderMermaid(els) {
-  if (!els || !els.length) return;
+export async function renderMermaid() {
+  const els = document.querySelectorAll('.markup code.language-mermaid');
+  if (!els?.length) return;
 
   const {default: mermaid} = await import(/* webpackChunkName: "mermaid" */'mermaid');
 

web_src/js/svg.js

@@ -1,5 +1,6 @@
 import octiconChevronDown from '../../public/img/svg/octicon-chevron-down.svg';
 import octiconChevronRight from '../../public/img/svg/octicon-chevron-right.svg';
+import octiconCopy from '../../public/img/svg/octicon-copy.svg';
 import octiconGitMerge from '../../public/img/svg/octicon-git-merge.svg';
 import octiconGitPullRequest from '../../public/img/svg/octicon-git-pull-request.svg';
 import octiconIssueClosed from '../../public/img/svg/octicon-issue-closed.svg';
@@ -20,6 +21,7 @@ import Vue from 'vue';
 export const svgs = {
   'octicon-chevron-down': octiconChevronDown,
   'octicon-chevron-right': octiconChevronRight,
+  'octicon-copy': octiconCopy,
   'octicon-git-merge': octiconGitMerge,
   'octicon-git-pull-request': octiconGitPullRequest,
   'octicon-issue-closed': octiconIssueClosed,
@@ -38,18 +40,33 @@ export const svgs = {
 
 const parser = new DOMParser();
 const serializer = new XMLSerializer();
+const parsedSvgs = new Map();
 
-// retrieve a HTML string for given SVG icon name, size and additional classes
-export function svg(name, size = 16, className = '') {
+function getParsedSvg(name) {
+  if (parsedSvgs.has(name)) return parsedSvgs.get(name);
+  const root = parser.parseFromString(svgs[name], 'text/html');
+  const svgNode = root.querySelector('svg');
+  parsedSvgs.set(name, svgNode);
+  return svgNode;
+}
+
+function applyAttributes(node, size, className) {
+  if (size !== 16) node.setAttribute('width', String(size));
+  if (size !== 16) node.setAttribute('height', String(size));
+  if (className) node.classList.add(...className.split(/\s+/));
+  return node;
+}
+
+// returns a SVG node for given SVG icon name, size and additional classes
+export function svgNode(name, size = 16, className = '') {
+  return applyAttributes(getParsedSvg(name), size, className);
+}
+
+// returns a HTML string for given SVG icon name, size and additional classes
+export function svg(name, size, className) {
   if (!(name in svgs)) return '';
   if (size === 16 && !className) return svgs[name];
-
-  const document = parser.parseFromString(svgs[name], 'image/svg+xml');
-  const svgNode = document.firstChild;
-  if (size !== 16) svgNode.setAttribute('width', String(size));
-  if (size !== 16) svgNode.setAttribute('height', String(size));
-  if (className) svgNode.classList.add(...className.split(/\s+/));
-  return serializer.serializeToString(svgNode);
+  return serializer.serializeToString(svgNode(name, size, className));
 }
 
 export const SvgIcon = Vue.component('SvgIcon', {

web_src/less/animations.less

@@ -0,0 +1,17 @@
+@keyframes fadein {
+  0% {
+    opacity: 0;
+  }
+  100% {
+    opacity: 1;
+  }
+}
+
+@keyframes fadeout {
+  0% {
+    opacity: 1;
+  }
+  100% {
+    opacity: 0;
+  }
+}

web_src/less/index.less

@@ -1,6 +1,7 @@
 @import "font-awesome/css/font-awesome.css";
 
 @import "./variables.less";
+@import "./animations.less";
 @import "./shared/issuelist.less";
 @import "./features/animations.less";
 @import "./features/dropzone.less";
@@ -11,6 +12,7 @@
 @import "./features/projects.less";
 @import "./markup/content.less";
 @import "./markup/mermaid.less";
+@import "./markup/codecopy.less";
 @import "./code/linebutton.less";
 
 @import "./chroma/base.less";

web_src/less/markup/codecopy.less

@@ -0,0 +1,25 @@
+.markup .code-block {
+  position: relative;
+}
+
+.markup .code-copy {
+  position: absolute;
+  top: .5rem;
+  right: .5rem;
+  padding: 10px;
+  visibility: hidden;
+  animation: fadeout .2s both;
+}
+
+.markup .code-copy:hover {
+  background: var(--color-secondary) !important;
+}
+
+.markup .code-copy:active {
+  background: var(--color-secondary-dark-1) !important;
+}
+
+.markup .code-block:hover .code-copy {
+  visibility: visible;
+  animation: fadein .2s both;
+}