blob: 1f7850ebb5fda7ddeb9e1a297bcef0c87ab3aa43 [file] [log] [blame]
// Copyright 2013 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.
//go:build go1.16
// +build go1.16
package web
import (
"bytes"
"fmt"
"html/template"
"io/fs"
"log"
"path"
"regexp"
"strings"
"golang.org/x/website/internal/history"
"golang.org/x/website/internal/texthtml"
)
func (s *Site) initDocFuncs() {
s.docFuncs = template.FuncMap{
"code": s.code,
"releases": func() []*history.Major { return history.Majors },
}
}
func (s *Site) code(file string, arg ...interface{}) (_ template.HTML, err error) {
defer func() {
if r := recover(); r != nil {
err = fmt.Errorf("%v", r)
}
}()
file = path.Clean(strings.TrimPrefix(file, "/"))
btext, err := fs.ReadFile(s.fs, file)
if err != nil {
return "", err
}
text := string(btext)
var command string
switch len(arg) {
case 0:
// text is already whole file.
command = fmt.Sprintf("code %q", file)
case 1:
command = fmt.Sprintf("code %q %s", file, stringFor(arg[0]))
text = s.oneLine(file, text, arg[0])
case 2:
command = fmt.Sprintf("code %q %s %s", file, stringFor(arg[0]), stringFor(arg[1]))
text = s.multipleLines(file, text, arg[0], arg[1])
default:
return "", fmt.Errorf("incorrect code invocation: code %q [%v, ...] (%d arguments)", file, arg[0], len(arg))
}
// Trim spaces from output.
text = strings.Trim(text, "\n")
// Replace tabs by spaces, which work better in HTML.
text = strings.Replace(text, "\t", " ", -1)
var buf bytes.Buffer
// HTML-escape text and syntax-color comments like elsewhere.
buf.Write(texthtml.Format([]byte(text), texthtml.Config{GoComments: true}))
// Include the command as a comment.
text = fmt.Sprintf("<pre><!--{{%s}}\n-->%s</pre>", command, buf.Bytes())
return template.HTML(text), nil
}
// Functions in this file panic on error, but the panic is recovered
// to an error by 'code'.
// stringFor returns a textual representation of the arg, formatted according to its nature.
func stringFor(arg interface{}) string {
switch arg := arg.(type) {
case int:
return fmt.Sprintf("%d", arg)
case string:
if len(arg) > 2 && arg[0] == '/' && arg[len(arg)-1] == '/' {
return fmt.Sprintf("%#q", arg)
}
return fmt.Sprintf("%q", arg)
default:
log.Panicf("unrecognized argument: %v type %T", arg, arg)
}
return ""
}
// oneLine returns the single line generated by a two-argument code invocation.
func (s *Site) oneLine(file, text string, arg interface{}) string {
lines := strings.SplitAfter(text, "\n")
line, pattern, isInt := parseArg(arg, file, len(lines))
if isInt {
return lines[line-1]
}
return lines[match(file, 0, lines, pattern)-1]
}
// multipleLines returns the text generated by a three-argument code invocation.
func (s *Site) multipleLines(file, text string, arg1, arg2 interface{}) string {
lines := strings.SplitAfter(text, "\n")
line1, pattern1, isInt1 := parseArg(arg1, file, len(lines))
line2, pattern2, isInt2 := parseArg(arg2, file, len(lines))
if !isInt1 {
line1 = match(file, 0, lines, pattern1)
}
if !isInt2 {
line2 = match(file, line1, lines, pattern2)
} else if line2 < line1 {
log.Panicf("lines out of order for %q: %d %d", file, line1, line2)
}
for k := line1 - 1; k < line2; k++ {
if strings.HasSuffix(lines[k], "OMIT\n") {
lines[k] = ""
}
}
return strings.Join(lines[line1-1:line2], "")
}
// parseArg returns the integer or string value of the argument and tells which it is.
func parseArg(arg interface{}, file string, max int) (ival int, sval string, isInt bool) {
switch n := arg.(type) {
case int:
if n <= 0 || n > max {
log.Panicf("%q:%d is out of range", file, n)
}
return n, "", true
case string:
return 0, n, false
}
log.Panicf("unrecognized argument %v type %T", arg, arg)
return
}
// match identifies the input line that matches the pattern in a code invocation.
// If start>0, match lines starting there rather than at the beginning.
// The return value is 1-indexed.
func match(file string, start int, lines []string, pattern string) int {
// $ matches the end of the file.
if pattern == "$" {
if len(lines) == 0 {
log.Panicf("%q: empty file", file)
}
return len(lines)
}
// /regexp/ matches the line that matches the regexp.
if len(pattern) > 2 && pattern[0] == '/' && pattern[len(pattern)-1] == '/' {
re, err := regexp.Compile(pattern[1 : len(pattern)-1])
if err != nil {
log.Panic(err)
}
for i := start; i < len(lines); i++ {
if re.MatchString(lines[i]) {
return i + 1
}
}
log.Panicf("%s: no match for %#q", file, pattern)
}
log.Panicf("unrecognized pattern: %q", pattern)
return 0
}