Direct SVG rendering (go-gitea#12157)

Introduce 'make svg' which calls a node script that compiles svg files
to `public/img/svg`. These files are vendored to not create a dependency
on Node for the backend build.

On the frontend side, configure webpack using `raw-loader` so SVGs can
be imported as string.

Also moved our existing SVGs to web_src/svg for consistency.

Fixes: go-gitea#11618

.gitignore

@@ -79,7 +79,6 @@ coverage.all
 /public/serviceworker.js
 /public/css
 /public/fonts
-/public/img/svg
 /web_src/fomantic/build
 /VERSION
 

Makefile

@@ -95,11 +95,13 @@ FOMANTIC_DEST_DIR := web_src/fomantic/build
 WEBPACK_SOURCES := $(shell find web_src/js web_src/less -type f) $(FOMANTIC_DEST)
 WEBPACK_CONFIGS := webpack.config.js
 WEBPACK_DEST := public/js/index.js public/css/index.css
-WEBPACK_DEST_ENTRIES := public/js public/css public/fonts public/serviceworker.js public/img/svg
+WEBPACK_DEST_ENTRIES := public/js public/css public/fonts public/serviceworker.js
 
 BINDATA_DEST := modules/public/bindata.go modules/options/bindata.go modules/templates/bindata.go
 BINDATA_HASH := $(addsuffix .hash,$(BINDATA_DEST))
 
+SVG_DEST_DIR := public/img/svg
+
 TAGS ?=
 TAGS_SPLIT := $(subst $(COMMA), ,$(TAGS))
 TAGS_EVIDENCE := $(MAKE_EVIDENCE_DIR)/tags
@@ -158,6 +160,7 @@ help:
 	@echo " - lint-backend                     lint backend files"
 	@echo " - watch-frontend                   watch frontend files and continuously rebuild"
 	@echo " - webpack                          build webpack files"
+	@echo " - svg                              build svg files"
 	@echo " - fomantic                         build fomantic files"
 	@echo " - generate                         run \"go generate\""
 	@echo " - fmt                              format the Go code"
@@ -292,8 +295,8 @@ lint: lint-backend lint-frontend
 lint-backend: golangci-lint revive vet swagger-check swagger-validate test-vendor
 
 .PHONY: lint-frontend
-lint-frontend: node_modules
-	npx eslint web_src/js webpack.config.js
+lint-frontend: node_modules svg-check
+	npx eslint web_src/js build webpack.config.js
 	npx stylelint web_src/less
 
 .PHONY: watch-frontend
@@ -605,6 +608,20 @@ $(WEBPACK_DEST): $(WEBPACK_SOURCES) $(WEBPACK_CONFIGS) package-lock.json | node_
 	npx webpack --hide-modules --display-entrypoints=false
 	@touch $(WEBPACK_DEST)
 
+.PHONY: svg
+svg: node-check | node_modules
+	rm -rf $(SVG_DEST_DIR)
+	node build/generate-svg.js
+
+.PHONY: svg-check
+svg-check: svg
+	@diff=$$(git diff $(SVG_DEST_DIR)); \
+	if [ -n "$$diff" ]; then \
+		echo "Please run 'make svg' and commit the result:"; \
+		echo "$${diff}"; \
+		exit 1; \
+	fi;
+
 .PHONY: update-translations
 update-translations:
 	mkdir -p ./translations

build/generate-svg.js

@@ -0,0 +1,63 @@
+#!/usr/bin/env node
+'use strict';
+
+const fastGlob = require('fast-glob');
+const Svgo = require('svgo');
+const {resolve, parse} = require('path');
+const {readFile, writeFile, mkdir} = require('fs').promises;
+
+const glob = (pattern) => fastGlob.sync(pattern, {cwd: resolve(__dirname), absolute: true});
+const outputDir = resolve(__dirname, '../public/img/svg');
+
+function exit(err) {
+  if (err) console.error(err);
+  process.exit(err ? 1 : 0);
+}
+
+async function processFile(file, {prefix = ''} = {}) {
+  const name = `${prefix}${parse(file).name}`;
+
+  const svgo = new Svgo({
+    plugins: [
+      {removeXMLNS: true},
+      {removeDimensions: true},
+      {
+        addClassesToSVGElement: {
+          classNames: [
+            'svg',
+            name,
+          ],
+        },
+      },
+      {
+        addAttributesToSVGElement: {
+          attributes: [
+            {'width': '16'},
+            {'height': '16'},
+            {'aria-hidden': 'true'},
+          ],
+        },
+      },
+    ],
+  });
+
+  const {data} = await svgo.optimize(await readFile(file, 'utf8'));
+  await writeFile(resolve(outputDir, `${name}.svg`), data);
+}
+
+async function main() {
+  try {
+    await mkdir(outputDir);
+  } catch {}
+
+  for (const file of glob('../node_modules/@primer/octicons/build/svg/*.svg')) {
+    await processFile(file, {prefix: 'octicon-'});
+  }
+
+  for (const file of glob('../web_src/svg/*.svg')) {
+    await processFile(file);
+  }
+}
+
+main().then(exit).catch(exit);
+

docs/content/doc/advanced/hacking-on-gitea.en-us.md

@@ -151,6 +151,10 @@ make lint-frontend
 
 Note: When working on frontend code, set `USE_SERVICE_WORKER` to `false` in `app.ini` to prevent undesirable caching of frontend assets.
 
+### Building and adding SVGs
+
+SVG icons are built using the `make svg` target which compiles the icon sources defined in `build/generate-svg.js` into the output directory `public/img/svg`. Custom icons can be added in the `web_src/svg` directory.
+
 ### Building Images
 
 To build the images, ImageMagick, `inkscape` and `zopflipng` binaries must be available in

modules/svg/discover_bindata.go

@@ -0,0 +1,32 @@
+// Copyright 2020 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+// +build bindata
+
+package svg
+
+import (
+	"path"
+	"path/filepath"
+
+	"code.gitea.io/gitea/modules/public"
+)
+
+// Discover returns a map of discovered SVG icons in bindata
+func Discover() map[string]string {
+	svgs := make(map[string]string)
+
+	for _, file := range public.AssetNames() {
+		matched, _ := filepath.Match("img/svg/*.svg", file)
+		if matched {
+			content, err := public.Asset(file)
+			if err == nil {
+				filename := path.Base(file)
+				svgs[filename[:len(filename)-4]] = string(content)
+			}
+		}
+	}
+
+	return svgs
+}

modules/svg/discover_nobindata.go

@@ -0,0 +1,31 @@
+// Copyright 2020 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+// +build !bindata
+
+package svg
+
+import (
+	"io/ioutil"
+	"path"
+	"path/filepath"
+
+	"code.gitea.io/gitea/modules/setting"
+)
+
+// Discover returns a map of discovered SVG icons in the file system
+func Discover() map[string]string {
+	svgs := make(map[string]string)
+
+	files, _ := filepath.Glob(path.Join(setting.StaticRootPath, "public", "img", "svg", "*.svg"))
+	for _, file := range files {
+		content, err := ioutil.ReadFile(file)
+		if err == nil {
+			filename := path.Base(file)
+			svgs[filename[:len(filename)-4]] = string(content)
+		}
+	}
+
+	return svgs
+}

modules/svg/svg.go

@@ -0,0 +1,13 @@
+// Copyright 2020 The Gitea Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+package svg
+
+// SVGs contains discovered SVGs
+var SVGs map[string]string
+
+// Init discovers SVGs and populates the `SVGs` variable
+func Init() {
+	SVGs = Discover()
+}

modules/templates/helper.go

@@ -30,6 +30,7 @@ import (
 	"code.gitea.io/gitea/modules/markup"
 	"code.gitea.io/gitea/modules/repository"
 	"code.gitea.io/gitea/modules/setting"
+	"code.gitea.io/gitea/modules/svg"
 	"code.gitea.io/gitea/modules/timeutil"
 	"code.gitea.io/gitea/modules/util"
 	"code.gitea.io/gitea/services/gitdiff"
@@ -439,9 +440,19 @@ func NewTextFuncMap() []texttmpl.FuncMap {
 	}}
 }
 
+var widthRe = regexp.MustCompile(`width="[0-9]+?"`)
+var heightRe = regexp.MustCompile(`height="[0-9]+?"`)
+
 // SVG render icons
 func SVG(icon string, size int) template.HTML {
-	return template.HTML(fmt.Sprintf(`<svg class="svg %s" width="%d" height="%d" aria-hidden="true"><use xlink:href="#%s" /></svg>`, icon, size, size, icon))
+	if svgStr, ok := svg.SVGs[icon]; ok {
+		if size != 16 {
+			svgStr = widthRe.ReplaceAllString(svgStr, fmt.Sprintf(`width="%d"`, size))
+			svgStr = heightRe.ReplaceAllString(svgStr, fmt.Sprintf(`height="%d"`, size))
+		}
+		return template.HTML(svgStr)
+	}
+	return template.HTML("")
 }
 
 // Safe render raw as HTML