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// Copyright 2009 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.
// Godoc comment -> HTML formatting
package comment
import (
"fmt";
"io";
"template";
)
// Split bytes into lines.
func split(text []byte) [][]byte {
// count lines
n := 0;
last := 0;
for i, c := range text {
if c == '\n' {
last = i+1;
n++;
}
}
if last < len(text) {
n++;
}
// split
out := make([][]byte, n);
last = 0;
n = 0;
for i, c := range text {
if c == '\n' {
out[n] = text[last : i+1];
last = i+1;
n++;
}
}
if last < len(text) {
out[n] = text[last : len(text)];
}
return out;
}
var (
ldquo = io.StringBytes("&ldquo;");
rdquo = io.StringBytes("&rdquo;");
)
// Escape comment text for HTML.
// Also, turn `` into &ldquo; and '' into &rdquo;.
func commentEscape(w io.Write, s []byte) {
last := 0;
for i := 0; i < len(s)-1; i++ {
if s[i] == s[i+1] && (s[i] == '`' || s[i] == '\'') {
template.HtmlEscape(w, s[last : i]);
last = i+2;
switch s[i] {
case '`':
w.Write(ldquo);
case '\'':
w.Write(rdquo);
}
i++; // loop will add one more
}
}
template.HtmlEscape(w, s[last : len(s)]);
}
var (
html_p = io.StringBytes("<p>\n");
html_endp = io.StringBytes("</p>\n");
html_pre = io.StringBytes("<pre>");
html_endpre = io.StringBytes("</pre>\n");
)
func indentLen(s []byte) int {
i := 0;
for i < len(s) && (s[i] == ' ' || s[i] == '\t') {
i++;
}
return i;
}
func isBlank(s []byte) bool {
return len(s) == 0 || (len(s) == 1 && s[0] == '\n')
}
func commonPrefix(a, b []byte) []byte {
i := 0;
for i < len(a) && i < len(b) && a[i] == b[i] {
i++;
}
return a[0 : i];
}
func unindent(block [][]byte) {
if len(block) == 0 {
return;
}
// compute maximum common white prefix
prefix := block[0][0 : indentLen(block[0])];
for i, line := range block {
if !isBlank(line) {
prefix = commonPrefix(prefix, line[0 : indentLen(line)]);
}
}
n := len(prefix);
// remove
for i, line := range block {
if !isBlank(line) {
block[i] = line[n : len(line)];
}
}
}
// Convert comment text to formatted HTML.
// The comment was prepared by DocReader,
// so it is known not to have leading, trailing blank lines
// nor to have trailing spaces at the end of lines.
// The comment markers have already been removed.
//
// Turn each run of multiple \n into </p><p>
// Turn each run of indented lines into <pre> without indent.
//
// TODO(rsc): I'd like to pass in an array of variable names []string
// and then italicize those strings when they appear as words.
func ToHtml(w io.Write, s []byte) {
inpara := false;
/* TODO(rsc): 6g cant generate code for these
close := func() {
if inpara {
w.Write(html_endp);
inpara = false;
}
};
open := func() {
if !inpara {
w.Write(html_p);
inpara = true;
}
};
*/
lines := split(s);
unindent(lines);
for i := 0; i < len(lines); {
line := lines[i];
if isBlank(line) {
// close paragraph
if inpara {
w.Write(html_endp);
inpara = false;
}
i++;
continue;
}
if indentLen(line) > 0 {
// close paragraph
if inpara {
w.Write(html_endp);
inpara = false;
}
// count indented or blank lines
j := i+1;
for j < len(lines) && (isBlank(lines[j]) || indentLen(lines[j]) > 0) {
j++;
}
// but not trailing blank lines
for j > i && isBlank(lines[j-1]) {
j--;
}
block := lines[i : j];
i = j;
unindent(block);
// put those lines in a pre block.
// they don't get the nice text formatting,
// just html escaping
w.Write(html_pre);
for k, line := range block {
template.HtmlEscape(w, line);
}
w.Write(html_endpre);
continue;
}
// open paragraph
if !inpara {
w.Write(html_p);
inpara = true;
}
commentEscape(w, lines[i]);
i++;
}
if inpara {
w.Write(html_endp);
inpara = false;
}
}