blob: f2de24c9e7677fbe341f8bd369571040e05c7d3a [file] [log] [blame]
// Copyright 2019 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Command css appends CSS styles to content/static/stylesheet.css.
// It reads from the CSS file at
// https://github.com/sindresorhus/github-markdown-css/blob/gh-pages/github-markdown.css
// and removes all styles that do not belong to a .markdown-body <tag>. The
// .markdown-body class is then replaced with .Overview-readmeContent, for use
// in the discovery codebase. The remaining properties are written to content/static/css/stylesheet.css.
package main
import (
"bufio"
"flag"
"fmt"
"io/ioutil"
"log"
"net/http"
"os"
"regexp"
"strconv"
"strings"
)
const (
cssFile = "content/static/css/readme.css"
githubStylesheet = "https://raw.githubusercontent.com/sindresorhus/github-markdown-css/gh-pages/github-markdown.css"
githubREADMEClass = ".markdown-body"
discoveryREADMEClass = ".Overview-readmeContent"
copyright = `/*
* Copyright 2019-2020 The Go Authors. All rights reserved.
* Use of this source code is governed by a BSD-style
* license that can be found in the LICENSE file.
*/
`
)
var write = flag.Bool("write", false, "append modifications to content/static/css/stylesheet.css")
func main() {
flag.Parse()
resp, err := http.Get(githubStylesheet)
if err != nil {
log.Fatalf("http.Get(%q): %v", githubStylesheet, err)
}
if resp.StatusCode != http.StatusOK {
log.Fatalf("http.Get(%q): status = %d", githubStylesheet, resp.StatusCode)
}
defer resp.Body.Close()
scanner := bufio.NewScanner(resp.Body)
var (
atPropertyStart = true
curr string
includeProperty bool
properties []string
)
for scanner.Scan() {
text := scanner.Text()
if headerString := replaceHeaderTag(text); headerString != "" {
text = headerString
}
if atPropertyStart && shouldIncludeProperty(text) {
includeProperty = true
}
if remString := replaceValueWithRems(text); remString != "" {
text = remString
}
if text == "}" {
if includeProperty {
properties = append(properties, curr+text+"\n")
}
curr = ""
includeProperty = false
atPropertyStart = true
continue
}
if includeProperty {
curr += text
curr += "\n"
}
}
if err := scanner.Err(); err != nil {
log.Fatal(err)
}
if err := ioutil.WriteFile(cssFile, []byte(copyright), 0644); err != nil {
log.Fatalf("ioutil.WriteFile(f, '', 0644): %v", err)
}
file, err := os.OpenFile(cssFile, os.O_WRONLY|os.O_APPEND, 0644)
if err != nil {
log.Fatalf("os.OpenFile(f, os.O_WRONLY|os.O_APPEND, 0644): %v", err)
}
defer func() {
if err := file.Close(); err != nil {
log.Fatalf("file.Close(): %v", err)
}
}()
if !*write {
fmt.Println("Dryrun only. Run with `-write` to write to stylesheet.css.")
} else {
fmt.Printf("Writing these properties to %q: \n", cssFile)
}
contentsToWrite := `
/* ---------- */
/*
/* The CSS classes below are generated using devtools/cmd/css/main.go
/* If the generated CSS already exists, the file is overwritten
/*
/* ---------- */`
contentsToWrite += "\n\n"
for _, p := range properties {
contentsToWrite += strings.ReplaceAll(p, githubREADMEClass, discoveryREADMEClass)
}
contentsToWrite += `
/* ---------- */
/*
/* End output from devtools/cmd/css/main.go
/*
/* ---------- */`
fmt.Println(contentsToWrite)
if _, err := file.WriteString(contentsToWrite); err != nil {
log.Fatalf("file.WriteString(%q): %v", contentsToWrite, err)
}
}
// replaceHeaderTag finds any header tags in a line of text and increases
// the header level by 2. replaceHeader tag returns the replaced string if a
// header tag is found and returns an empty string if not
func replaceHeaderTag(property string) string {
headerMap := map[string]string{
"h1": "h3", "h2": "h4", "h3": "h5", "h4": "h6", "h5": "div[aria-level=7]", "h6": "div[aria-level=8]",
}
for k, v := range headerMap {
if strings.Contains(property, k) {
return strings.ReplaceAll(property, k, v)
}
}
return ""
}
// shouldIncludeProperty reports whether this property should be included in
// the CSS file.
func shouldIncludeProperty(property string) bool {
parts := strings.Split(property, " ")
if len(parts) < 1 {
return false
}
if parts[0] != githubREADMEClass {
return false
}
for _, p := range parts[1:] {
if strings.HasPrefix(p, ".") {
return false
}
}
return true
}
// pxToRem returns the number value of a px string to a rem string.
func pxToRem(value string) string {
valueNum, err := strconv.ParseFloat(value, 32)
if err != nil {
return ""
}
valueNum = valueNum / 16
return fmt.Sprintf("%frem", valueNum)
}
// replaceValueWithRems replaces the px values in a line of css with rems.
// e.g: padding: 25px 10px => padding:
func replaceValueWithRems(line string) string {
var cssLine string
valueRegex := regexp.MustCompile(`([-+]?[0-9]*\.?[0-9]+)px`)
matches := valueRegex.FindAllStringSubmatchIndex(line, -1)
for idx, m := range matches {
// e.g: "padding: 6px 13px;" => "padding: 0.375rem 0.8125rem;"
// padding: [valueStartIdx][numStartIdx]25[numEndIdx]px[valueEndIdx] 10em;
// The value here is the full string "25px" and num is just "25".
valueStartIdx, valueEndIdx, numStartIdx, numEndIdx := m[0], m[1], m[2], m[3]
if idx == 0 {
cssLine += line[0:valueStartIdx]
}
cssLine += pxToRem(line[numStartIdx:numEndIdx])
if idx == len(matches)-1 {
cssLine += line[valueEndIdx:]
} else {
// If there are more matches for "px", add up until the start of the next match.
cssLine += line[valueEndIdx:matches[idx+1][0]]
}
}
return cssLine
}