524 lines
11 KiB
Go
524 lines
11 KiB
Go
|
// Copyright 2010 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.
|
||
|
|
|
||
|
|
// The /doc/codewalk/ tree is synthesized from codewalk descriptions,
|
||
|
|
// files named $GOROOT/doc/codewalk/*.xml.
|
||
|
|
// For an example and a description of the format, see
|
||
|
|
// http://golang.org/doc/codewalk/codewalk or run godoc -http=:6060
|
||
|
|
// and see http://localhost:6060/doc/codewalk/codewalk .
|
||
|
|
// That page is itself a codewalk; the source code for it is
|
||
|
|
// $GOROOT/doc/codewalk/codewalk.xml.
|
||
|
|
|
||
|
|
package main
|
||
|
|
|
||
|
|
import (
|
||
|
|
"bytes"
|
||
|
|
"encoding/xml"
|
||
|
|
"errors"
|
||
|
|
"fmt"
|
||
|
|
"io"
|
||
|
|
"log"
|
||
|
|
"net/http"
|
||
|
|
"os"
|
||
|
|
pathpkg "path"
|
||
|
|
"regexp"
|
||
|
|
"sort"
|
||
|
|
"strconv"
|
||
|
|
"strings"
|
||
|
|
"text/template"
|
||
|
|
"unicode/utf8"
|
||
|
|
|
||
|
|
"golang.org/x/tools/godoc"
|
||
|
|
"golang.org/x/tools/godoc/vfs"
|
||
|
|
)
|
||
|
|
|
||
|
|
var codewalkHTML, codewalkdirHTML *template.Template
|
||
|
|
|
||
|
|
// Handler for /doc/codewalk/ and below.
|
||
|
|
func codewalk(w http.ResponseWriter, r *http.Request) {
|
||
|
|
relpath := r.URL.Path[len("/doc/codewalk/"):]
|
||
|
|
abspath := r.URL.Path
|
||
|
|
|
||
|
|
r.ParseForm()
|
||
|
|
if f := r.FormValue("fileprint"); f != "" {
|
||
|
|
codewalkFileprint(w, r, f)
|
||
|
|
return
|
||
|
|
}
|
||
|
|
|
||
|
|
// If directory exists, serve list of code walks.
|
||
|
|
dir, err := fs.Lstat(abspath)
|
||
|
|
if err == nil && dir.IsDir() {
|
||
|
|
codewalkDir(w, r, relpath, abspath)
|
||
|
|
return
|
||
|
|
}
|
||
|
|
|
||
|
|
// If file exists, serve using standard file server.
|
||
|
|
if err == nil {
|
||
|
|
pres.ServeFile(w, r)
|
||
|
|
return
|
||
|
|
}
|
||
|
|
|
||
|
|
// Otherwise append .xml and hope to find
|
||
|
|
// a codewalk description, but before trim
|
||
|
|
// the trailing /.
|
||
|
|
abspath = strings.TrimRight(abspath, "/")
|
||
|
|
cw, err := loadCodewalk(abspath + ".xml")
|
||
|
|
if err != nil {
|
||
|
|
log.Print(err)
|
||
|
|
pres.ServeError(w, r, relpath, err)
|
||
|
|
return
|
||
|
|
}
|
||
|
|
|
||
|
|
// Canonicalize the path and redirect if changed
|
||
|
|
if redir(w, r) {
|
||
|
|
return
|
||
|
|
}
|
||
|
|
|
||
|
|
pres.ServePage(w, godoc.Page{
|
||
|
|
Title: "Codewalk: " + cw.Title,
|
||
|
|
Tabtitle: cw.Title,
|
||
|
|
Body: applyTemplate(codewalkHTML, "codewalk", cw),
|
||
|
|
})
|
||
|
|
}
|
||
|
|
|
||
|
|
func redir(w http.ResponseWriter, r *http.Request) (redirected bool) {
|
||
|
|
canonical := pathpkg.Clean(r.URL.Path)
|
||
|
|
if !strings.HasSuffix(canonical, "/") {
|
||
|
|
canonical += "/"
|
||
|
|
}
|
||
|
|
if r.URL.Path != canonical {
|
||
|
|
url := *r.URL
|
||
|
|
url.Path = canonical
|
||
|
|
http.Redirect(w, r, url.String(), http.StatusMovedPermanently)
|
||
|
|
redirected = true
|
||
|
|
}
|
||
|
|
return
|
||
|
|
}
|
||
|
|
|
||
|
|
func applyTemplate(t *template.Template, name string, data interface{}) []byte {
|
||
|
|
var buf bytes.Buffer
|
||
|
|
if err := t.Execute(&buf, data); err != nil {
|
||
|
|
log.Printf("%s.Execute: %s", name, err)
|
||
|
|
}
|
||
|
|
return buf.Bytes()
|
||
|
|
}
|
||
|
|
|
||
|
|
// A Codewalk represents a single codewalk read from an XML file.
|
||
|
|
type Codewalk struct {
|
||
|
|
Title string `xml:"title,attr"`
|
||
|
|
File []string `xml:"file"`
|
||
|
|
Step []*Codestep `xml:"step"`
|
||
|
|
}
|
||
|
|
|
||
|
|
// A Codestep is a single step in a codewalk.
|
||
|
|
type Codestep struct {
|
||
|
|
// Filled in from XML
|
||
|
|
Src string `xml:"src,attr"`
|
||
|
|
Title string `xml:"title,attr"`
|
||
|
|
XML string `xml:",innerxml"`
|
||
|
|
|
||
|
|
// Derived from Src; not in XML.
|
||
|
|
Err error
|
||
|
|
File string
|
||
|
|
Lo int
|
||
|
|
LoByte int
|
||
|
|
Hi int
|
||
|
|
HiByte int
|
||
|
|
Data []byte
|
||
|
|
}
|
||
|
|
|
||
|
|
// String method for printing in template.
|
||
|
|
// Formats file address nicely.
|
||
|
|
func (st *Codestep) String() string {
|
||
|
|
s := st.File
|
||
|
|
if st.Lo != 0 || st.Hi != 0 {
|
||
|
|
s += fmt.Sprintf(":%d", st.Lo)
|
||
|
|
if st.Lo != st.Hi {
|
||
|
|
s += fmt.Sprintf(",%d", st.Hi)
|
||
|
|
}
|
||
|
|
}
|
||
|
|
return s
|
||
|
|
}
|
||
|
|
|
||
|
|
// loadCodewalk reads a codewalk from the named XML file.
|
||
|
|
func loadCodewalk(filename string) (*Codewalk, error) {
|
||
|
|
f, err := fs.Open(filename)
|
||
|
|
if err != nil {
|
||
|
|
return nil, err
|
||
|
|
}
|
||
|
|
defer f.Close()
|
||
|
|
cw := new(Codewalk)
|
||
|
|
d := xml.NewDecoder(f)
|
||
|
|
d.Entity = xml.HTMLEntity
|
||
|
|
err = d.Decode(cw)
|
||
|
|
if err != nil {
|
||
|
|
return nil, &os.PathError{Op: "parsing", Path: filename, Err: err}
|
||
|
|
}
|
||
|
|
|
||
|
|
// Compute file list, evaluate line numbers for addresses.
|
||
|
|
m := make(map[string]bool)
|
||
|
|
for _, st := range cw.Step {
|
||
|
|
i := strings.Index(st.Src, ":")
|
||
|
|
if i < 0 {
|
||
|
|
i = len(st.Src)
|
||
|
|
}
|
||
|
|
filename := st.Src[0:i]
|
||
|
|
data, err := vfs.ReadFile(fs, filename)
|
||
|
|
if err != nil {
|
||
|
|
st.Err = err
|
||
|
|
continue
|
||
|
|
}
|
||
|
|
if i < len(st.Src) {
|
||
|
|
lo, hi, err := addrToByteRange(st.Src[i+1:], 0, data)
|
||
|
|
if err != nil {
|
||
|
|
st.Err = err
|
||
|
|
continue
|
||
|
|
}
|
||
|
|
// Expand match to line boundaries.
|
||
|
|
for lo > 0 && data[lo-1] != '\n' {
|
||
|
|
lo--
|
||
|
|
}
|
||
|
|
for hi < len(data) && (hi == 0 || data[hi-1] != '\n') {
|
||
|
|
hi++
|
||
|
|
}
|
||
|
|
st.Lo = byteToLine(data, lo)
|
||
|
|
st.Hi = byteToLine(data, hi-1)
|
||
|
|
}
|
||
|
|
st.Data = data
|
||
|
|
st.File = filename
|
||
|
|
m[filename] = true
|
||
|
|
}
|
||
|
|
|
||
|
|
// Make list of files
|
||
|
|
cw.File = make([]string, len(m))
|
||
|
|
i := 0
|
||
|
|
for f := range m {
|
||
|
|
cw.File[i] = f
|
||
|
|
i++
|
||
|
|
}
|
||
|
|
sort.Strings(cw.File)
|
||
|
|
|
||
|
|
return cw, nil
|
||
|
|
}
|
||
|
|
|
||
|
|
// codewalkDir serves the codewalk directory listing.
|
||
|
|
// It scans the directory for subdirectories or files named *.xml
|
||
|
|
// and prepares a table.
|
||
|
|
func codewalkDir(w http.ResponseWriter, r *http.Request, relpath, abspath string) {
|
||
|
|
type elem struct {
|
||
|
|
Name string
|
||
|
|
Title string
|
||
|
|
}
|
||
|
|
|
||
|
|
dir, err := fs.ReadDir(abspath)
|
||
|
|
if err != nil {
|
||
|
|
log.Print(err)
|
||
|
|
pres.ServeError(w, r, relpath, err)
|
||
|
|
return
|
||
|
|
}
|
||
|
|
var v []interface{}
|
||
|
|
for _, fi := range dir {
|
||
|
|
name := fi.Name()
|
||
|
|
if fi.IsDir() {
|
||
|
|
v = append(v, &elem{name + "/", ""})
|
||
|
|
} else if strings.HasSuffix(name, ".xml") {
|
||
|
|
cw, err := loadCodewalk(abspath + "/" + name)
|
||
|
|
if err != nil {
|
||
|
|
continue
|
||
|
|
}
|
||
|
|
v = append(v, &elem{name[0 : len(name)-len(".xml")], cw.Title})
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
pres.ServePage(w, godoc.Page{
|
||
|
|
Title: "Codewalks",
|
||
|
|
Body: applyTemplate(codewalkdirHTML, "codewalkdir", v),
|
||
|
|
})
|
||
|
|
}
|
||
|
|
|
||
|
|
// codewalkFileprint serves requests with ?fileprint=f&lo=lo&hi=hi.
|
||
|
|
// The filename f has already been retrieved and is passed as an argument.
|
||
|
|
// Lo and hi are the numbers of the first and last line to highlight
|
||
|
|
// in the response. This format is used for the middle window pane
|
||
|
|
// of the codewalk pages. It is a separate iframe and does not get
|
||
|
|
// the usual godoc HTML wrapper.
|
||
|
|
func codewalkFileprint(w http.ResponseWriter, r *http.Request, f string) {
|
||
|
|
abspath := f
|
||
|
|
data, err := vfs.ReadFile(fs, abspath)
|
||
|
|
if err != nil {
|
||
|
|
log.Print(err)
|
||
|
|
pres.ServeError(w, r, f, err)
|
||
|
|
return
|
||
|
|
}
|
||
|
|
lo, _ := strconv.Atoi(r.FormValue("lo"))
|
||
|
|
hi, _ := strconv.Atoi(r.FormValue("hi"))
|
||
|
|
if hi < lo {
|
||
|
|
hi = lo
|
||
|
|
}
|
||
|
|
lo = lineToByte(data, lo)
|
||
|
|
hi = lineToByte(data, hi+1)
|
||
|
|
|
||
|
|
// Put the mark 4 lines before lo, so that the iframe
|
||
|
|
// shows a few lines of context before the highlighted
|
||
|
|
// section.
|
||
|
|
n := 4
|
||
|
|
mark := lo
|
||
|
|
for ; mark > 0 && n > 0; mark-- {
|
||
|
|
if data[mark-1] == '\n' {
|
||
|
|
if n--; n == 0 {
|
||
|
|
break
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
io.WriteString(w, `<style type="text/css">@import "/doc/codewalk/codewalk.css";</style><pre>`)
|
||
|
|
template.HTMLEscape(w, data[0:mark])
|
||
|
|
io.WriteString(w, "<a name='mark'></a>")
|
||
|
|
template.HTMLEscape(w, data[mark:lo])
|
||
|
|
if lo < hi {
|
||
|
|
io.WriteString(w, "<div class='codewalkhighlight'>")
|
||
|
|
template.HTMLEscape(w, data[lo:hi])
|
||
|
|
io.WriteString(w, "</div>")
|
||
|
|
}
|
||
|
|
template.HTMLEscape(w, data[hi:])
|
||
|
|
io.WriteString(w, "</pre>")
|
||
|
|
}
|
||
|
|
|
||
|
|
// addrToByte evaluates the given address starting at offset start in data.
|
||
|
|
// It returns the lo and hi byte offset of the matched region within data.
|
||
|
|
// See http://plan9.bell-labs.com/sys/doc/sam/sam.html Table II
|
||
|
|
// for details on the syntax.
|
||
|
|
func addrToByteRange(addr string, start int, data []byte) (lo, hi int, err error) {
|
||
|
|
var (
|
||
|
|
dir byte
|
||
|
|
prevc byte
|
||
|
|
charOffset bool
|
||
|
|
)
|
||
|
|
lo = start
|
||
|
|
hi = start
|
||
|
|
for addr != "" && err == nil {
|
||
|
|
c := addr[0]
|
||
|
|
switch c {
|
||
|
|
default:
|
||
|
|
err = errors.New("invalid address syntax near " + string(c))
|
||
|
|
case ',':
|
||
|
|
if len(addr) == 1 {
|
||
|
|
hi = len(data)
|
||
|
|
} else {
|
||
|
|
_, hi, err = addrToByteRange(addr[1:], hi, data)
|
||
|
|
}
|
||
|
|
return
|
||
|
|
|
||
|
|
case '+', '-':
|
||
|
|
if prevc == '+' || prevc == '-' {
|
||
|
|
lo, hi, err = addrNumber(data, lo, hi, prevc, 1, charOffset)
|
||
|
|
}
|
||
|
|
dir = c
|
||
|
|
|
||
|
|
case '$':
|
||
|
|
lo = len(data)
|
||
|
|
hi = len(data)
|
||
|
|
if len(addr) > 1 {
|
||
|
|
dir = '+'
|
||
|
|
}
|
||
|
|
|
||
|
|
case '#':
|
||
|
|
charOffset = true
|
||
|
|
|
||
|
|
case '0', '1', '2', '3', '4', '5', '6', '7', '8', '9':
|
||
|
|
var i int
|
||
|
|
for i = 1; i < len(addr); i++ {
|
||
|
|
if addr[i] < '0' || addr[i] > '9' {
|
||
|
|
break
|
||
|
|
}
|
||
|
|
}
|
||
|
|
var n int
|
||
|
|
n, err = strconv.Atoi(addr[0:i])
|
||
|
|
if err != nil {
|
||
|
|
break
|
||
|
|
}
|
||
|
|
lo, hi, err = addrNumber(data, lo, hi, dir, n, charOffset)
|
||
|
|
dir = 0
|
||
|
|
charOffset = false
|
||
|
|
prevc = c
|
||
|
|
addr = addr[i:]
|
||
|
|
continue
|
||
|
|
|
||
|
|
case '/':
|
||
|
|
var i, j int
|
||
|
|
Regexp:
|
||
|
|
for i = 1; i < len(addr); i++ {
|
||
|
|
switch addr[i] {
|
||
|
|
case '\\':
|
||
|
|
i++
|
||
|
|
case '/':
|
||
|
|
j = i + 1
|
||
|
|
break Regexp
|
||
|
|
}
|
||
|
|
}
|
||
|
|
if j == 0 {
|
||
|
|
j = i
|
||
|
|
}
|
||
|
|
pattern := addr[1:i]
|
||
|
|
lo, hi, err = addrRegexp(data, lo, hi, dir, pattern)
|
||
|
|
prevc = c
|
||
|
|
addr = addr[j:]
|
||
|
|
continue
|
||
|
|
}
|
||
|
|
prevc = c
|
||
|
|
addr = addr[1:]
|
||
|
|
}
|
||
|
|
|
||
|
|
if err == nil && dir != 0 {
|
||
|
|
lo, hi, err = addrNumber(data, lo, hi, dir, 1, charOffset)
|
||
|
|
}
|
||
|
|
if err != nil {
|
||
|
|
return 0, 0, err
|
||
|
|
}
|
||
|
|
return lo, hi, nil
|
||
|
|
}
|
||
|
|
|
||
|
|
// addrNumber applies the given dir, n, and charOffset to the address lo, hi.
|
||
|
|
// dir is '+' or '-', n is the count, and charOffset is true if the syntax
|
||
|
|
// used was #n. Applying +n (or +#n) means to advance n lines
|
||
|
|
// (or characters) after hi. Applying -n (or -#n) means to back up n lines
|
||
|
|
// (or characters) before lo.
|
||
|
|
// The return value is the new lo, hi.
|
||
|
|
func addrNumber(data []byte, lo, hi int, dir byte, n int, charOffset bool) (int, int, error) {
|
||
|
|
switch dir {
|
||
|
|
case 0:
|
||
|
|
lo = 0
|
||
|
|
hi = 0
|
||
|
|
fallthrough
|
||
|
|
|
||
|
|
case '+':
|
||
|
|
if charOffset {
|
||
|
|
pos := hi
|
||
|
|
for ; n > 0 && pos < len(data); n-- {
|
||
|
|
_, size := utf8.DecodeRune(data[pos:])
|
||
|
|
pos += size
|
||
|
|
}
|
||
|
|
if n == 0 {
|
||
|
|
return pos, pos, nil
|
||
|
|
}
|
||
|
|
break
|
||
|
|
}
|
||
|
|
// find next beginning of line
|
||
|
|
if hi > 0 {
|
||
|
|
for hi < len(data) && data[hi-1] != '\n' {
|
||
|
|
hi++
|
||
|
|
}
|
||
|
|
}
|
||
|
|
lo = hi
|
||
|
|
if n == 0 {
|
||
|
|
return lo, hi, nil
|
||
|
|
}
|
||
|
|
for ; hi < len(data); hi++ {
|
||
|
|
if data[hi] != '\n' {
|
||
|
|
continue
|
||
|
|
}
|
||
|
|
switch n--; n {
|
||
|
|
case 1:
|
||
|
|
lo = hi + 1
|
||
|
|
case 0:
|
||
|
|
return lo, hi + 1, nil
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
case '-':
|
||
|
|
if charOffset {
|
||
|
|
// Scan backward for bytes that are not UTF-8 continuation bytes.
|
||
|
|
pos := lo
|
||
|
|
for ; pos > 0 && n > 0; pos-- {
|
||
|
|
if data[pos]&0xc0 != 0x80 {
|
||
|
|
n--
|
||
|
|
}
|
||
|
|
}
|
||
|
|
if n == 0 {
|
||
|
|
return pos, pos, nil
|
||
|
|
}
|
||
|
|
break
|
||
|
|
}
|
||
|
|
// find earlier beginning of line
|
||
|
|
for lo > 0 && data[lo-1] != '\n' {
|
||
|
|
lo--
|
||
|
|
}
|
||
|
|
hi = lo
|
||
|
|
if n == 0 {
|
||
|
|
return lo, hi, nil
|
||
|
|
}
|
||
|
|
for ; lo >= 0; lo-- {
|
||
|
|
if lo > 0 && data[lo-1] != '\n' {
|
||
|
|
continue
|
||
|
|
}
|
||
|
|
switch n--; n {
|
||
|
|
case 1:
|
||
|
|
hi = lo
|
||
|
|
case 0:
|
||
|
|
return lo, hi, nil
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
return 0, 0, errors.New("address out of range")
|
||
|
|
}
|
||
|
|
|
||
|
|
// addrRegexp searches for pattern in the given direction starting at lo, hi.
|
||
|
|
// The direction dir is '+' (search forward from hi) or '-' (search backward from lo).
|
||
|
|
// Backward searches are unimplemented.
|
||
|
|
func addrRegexp(data []byte, lo, hi int, dir byte, pattern string) (int, int, error) {
|
||
|
|
re, err := regexp.Compile(pattern)
|
||
|
|
if err != nil {
|
||
|
|
return 0, 0, err
|
||
|
|
}
|
||
|
|
if dir == '-' {
|
||
|
|
// Could implement reverse search using binary search
|
||
|
|
// through file, but that seems like overkill.
|
||
|
|
return 0, 0, errors.New("reverse search not implemented")
|
||
|
|
}
|
||
|
|
m := re.FindIndex(data[hi:])
|
||
|
|
if len(m) > 0 {
|
||
|
|
m[0] += hi
|
||
|
|
m[1] += hi
|
||
|
|
} else if hi > 0 {
|
||
|
|
// No match. Wrap to beginning of data.
|
||
|
|
m = re.FindIndex(data)
|
||
|
|
}
|
||
|
|
if len(m) == 0 {
|
||
|
|
return 0, 0, errors.New("no match for " + pattern)
|
||
|
|
}
|
||
|
|
return m[0], m[1], nil
|
||
|
|
}
|
||
|
|
|
||
|
|
// lineToByte returns the byte index of the first byte of line n.
|
||
|
|
// Line numbers begin at 1.
|
||
|
|
func lineToByte(data []byte, n int) int {
|
||
|
|
if n <= 1 {
|
||
|
|
return 0
|
||
|
|
}
|
||
|
|
n--
|
||
|
|
for i, c := range data {
|
||
|
|
if c == '\n' {
|
||
|
|
if n--; n == 0 {
|
||
|
|
return i + 1
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|
||
|
|
return len(data)
|
||
|
|
}
|
||
|
|
|
||
|
|
// byteToLine returns the number of the line containing the byte at index i.
|
||
|
|
func byteToLine(data []byte, i int) int {
|
||
|
|
l := 1
|
||
|
|
for j, c := range data {
|
||
|
|
if j == i {
|
||
|
|
return l
|
||
|
|
}
|
||
|
|
if c == '\n' {
|
||
|
|
l++
|
||
|
|
}
|
||
|
|
}
|
||
|
|
return l
|
||
|
|
}
|