summaryrefslogtreecommitdiff
path: root/vendor/golang.org/x/net/dict/dict.go
blob: 93e65c03cfd971fea5ec9daf660621030c933476 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
// 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.

// Package dict implements the Dictionary Server Protocol
// as defined in RFC 2229.
package dict // import "golang.org/x/net/dict"

import (
	"net/textproto"
	"strconv"
	"strings"
)

// A Client represents a client connection to a dictionary server.
type Client struct {
	text *textproto.Conn
}

// Dial returns a new client connected to a dictionary server at
// addr on the given network.
func Dial(network, addr string) (*Client, error) {
	text, err := textproto.Dial(network, addr)
	if err != nil {
		return nil, err
	}
	_, _, err = text.ReadCodeLine(220)
	if err != nil {
		text.Close()
		return nil, err
	}
	return &Client{text: text}, nil
}

// Close closes the connection to the dictionary server.
func (c *Client) Close() error {
	return c.text.Close()
}

// A Dict represents a dictionary available on the server.
type Dict struct {
	Name string // short name of dictionary
	Desc string // long description
}

// Dicts returns a list of the dictionaries available on the server.
func (c *Client) Dicts() ([]Dict, error) {
	id, err := c.text.Cmd("SHOW DB")
	if err != nil {
		return nil, err
	}

	c.text.StartResponse(id)
	defer c.text.EndResponse(id)

	_, _, err = c.text.ReadCodeLine(110)
	if err != nil {
		return nil, err
	}
	lines, err := c.text.ReadDotLines()
	if err != nil {
		return nil, err
	}
	_, _, err = c.text.ReadCodeLine(250)

	dicts := make([]Dict, len(lines))
	for i := range dicts {
		d := &dicts[i]
		a, _ := fields(lines[i])
		if len(a) < 2 {
			return nil, textproto.ProtocolError("invalid dictionary: " + lines[i])
		}
		d.Name = a[0]
		d.Desc = a[1]
	}
	return dicts, err
}

// A Defn represents a definition.
type Defn struct {
	Dict Dict   // Dict where definition was found
	Word string // Word being defined
	Text []byte // Definition text, typically multiple lines
}

// Define requests the definition of the given word.
// The argument dict names the dictionary to use,
// the Name field of a Dict returned by Dicts.
//
// The special dictionary name "*" means to look in all the
// server's dictionaries.
// The special dictionary name "!" means to look in all the
// server's dictionaries in turn, stopping after finding the word
// in one of them.
func (c *Client) Define(dict, word string) ([]*Defn, error) {
	id, err := c.text.Cmd("DEFINE %s %q", dict, word)
	if err != nil {
		return nil, err
	}

	c.text.StartResponse(id)
	defer c.text.EndResponse(id)

	_, line, err := c.text.ReadCodeLine(150)
	if err != nil {
		return nil, err
	}
	a, _ := fields(line)
	if len(a) < 1 {
		return nil, textproto.ProtocolError("malformed response: " + line)
	}
	n, err := strconv.Atoi(a[0])
	if err != nil {
		return nil, textproto.ProtocolError("invalid definition count: " + a[0])
	}
	def := make([]*Defn, n)
	for i := 0; i < n; i++ {
		_, line, err = c.text.ReadCodeLine(151)
		if err != nil {
			return nil, err
		}
		a, _ := fields(line)
		if len(a) < 3 {
			// skip it, to keep protocol in sync
			i--
			n--
			def = def[0:n]
			continue
		}
		d := &Defn{Word: a[0], Dict: Dict{a[1], a[2]}}
		d.Text, err = c.text.ReadDotBytes()
		if err != nil {
			return nil, err
		}
		def[i] = d
	}
	_, _, err = c.text.ReadCodeLine(250)
	return def, err
}

// Fields returns the fields in s.
// Fields are space separated unquoted words
// or quoted with single or double quote.
func fields(s string) ([]string, error) {
	var v []string
	i := 0
	for {
		for i < len(s) && (s[i] == ' ' || s[i] == '\t') {
			i++
		}
		if i >= len(s) {
			break
		}
		if s[i] == '"' || s[i] == '\'' {
			q := s[i]
			// quoted string
			var j int
			for j = i + 1; ; j++ {
				if j >= len(s) {
					return nil, textproto.ProtocolError("malformed quoted string")
				}
				if s[j] == '\\' {
					j++
					continue
				}
				if s[j] == q {
					j++
					break
				}
			}
			v = append(v, unquote(s[i+1:j-1]))
			i = j
		} else {
			// atom
			var j int
			for j = i; j < len(s); j++ {
				if s[j] == ' ' || s[j] == '\t' || s[j] == '\\' || s[j] == '"' || s[j] == '\'' {
					break
				}
			}
			v = append(v, s[i:j])
			i = j
		}
		if i < len(s) {
			c := s[i]
			if c != ' ' && c != '\t' {
				return nil, textproto.ProtocolError("quotes not on word boundaries")
			}
		}
	}
	return v, nil
}

func unquote(s string) string {
	if strings.Index(s, "\\") < 0 {
		return s
	}
	b := []byte(s)
	w := 0
	for r := 0; r < len(b); r++ {
		c := b[r]
		if c == '\\' {
			r++
			c = b[r]
		}
		b[w] = c
		w++
	}
	return string(b[0:w])
}