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
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
|
"""URL / email matching helpers for the GFM autolink extension.
Ported from the Rust ``gfm_autolinks`` crate.
"""
from __future__ import annotations
import unicodedata
# ---------------------------------------------------------------------------
# Character classification helpers
# ---------------------------------------------------------------------------
_VALID_PREV_CHARS = frozenset(" \t\r\n*_~(")
def check_prev(ch: str) -> bool:
"""Return ``True`` if *ch* is a valid preceding character for an autolink."""
return ch in _VALID_PREV_CHARS
def _is_valid_hostchar(ch: str) -> bool:
"""Return ``True`` if *ch* is valid inside a domain label (not whitespace/punctuation)."""
if ch.isspace():
return False
cat = unicodedata.category(ch)
# Unicode punctuation categories: Pc, Pd, Pe, Pf, Pi, Po, Ps
return not cat.startswith("P")
# Characters that terminate a URL (before autolink_delim trimming).
_SPACE_CHARS = frozenset(" \t\r\n\x00\x0b\x0c")
def _isspace(ch: str) -> bool:
return ch in _SPACE_CHARS
_LINK_END_ASSORTMENT = frozenset("?!.,:*_~'\"[]")
def _autolink_delim(data: str, link_end: int) -> int:
"""Trim trailing punctuation from a URL according to GFM rules."""
# Truncate at first '<'
for i, ch in enumerate(data[:link_end]):
if ch == "<":
link_end = i
break
while link_end > 0:
cclose = data[link_end - 1]
copen = "(" if cclose == ")" else None
if cclose in _LINK_END_ASSORTMENT:
link_end -= 1
elif cclose == ";":
new_end = link_end - 2
while new_end > 0 and data[new_end].isalpha():
new_end -= 1
if new_end < link_end - 2 and data[new_end] == "&":
link_end = new_end
else:
link_end -= 1
elif copen is not None:
opening = data[:link_end].count(copen)
closing = data[:link_end].count(cclose)
if closing <= opening:
break
link_end -= 1
else:
break
return link_end
# ---------------------------------------------------------------------------
# Domain validation
# ---------------------------------------------------------------------------
def _check_domain(data: str, allow_short: bool) -> int | None:
"""Validate a domain name and return the length consumed, or ``None``."""
if not data:
return None
np = 0
uscore1 = 0
uscore2 = 0
for i, ch in enumerate(data):
if ch == "_":
uscore2 += 1
elif ch == ".":
uscore1 = uscore2
uscore2 = 0
np += 1
elif not _is_valid_hostchar(ch) and ch != "-":
if uscore1 == 0 and uscore2 == 0 and (allow_short or np > 0):
return i
return None
# else: valid hostchar or '-'
if (uscore1 > 0 or uscore2 > 0) and np <= 10:
return None
if allow_short or np > 0:
return len(data)
return None
# ---------------------------------------------------------------------------
# www matching
# ---------------------------------------------------------------------------
_EMAIL_OK = frozenset(".+-_")
def match_www(text: str) -> tuple[str, int] | None:
"""Match a bare ``www.`` URL at the start of *text*.
Returns ``(url_with_scheme, char_count)`` or ``None``.
"""
if not text.startswith("www."):
return None
link_end = _check_domain(text[4:], False)
if link_end is None:
return None
# link_end is offset from position 4
link_end += 4
# extend to the end of non-space characters
while link_end < len(text) and not _isspace(text[link_end]):
link_end += 1
link_end = _autolink_delim(text, link_end)
matched = text[:link_end]
url = "http://" + matched
return url, len(matched)
# ---------------------------------------------------------------------------
# http(s):// matching
# ---------------------------------------------------------------------------
def match_http(text: str) -> tuple[str, int] | None:
"""Match an ``http://`` or ``https://`` URL at the start of *text*.
Returns ``(url, char_count)`` or ``None``.
"""
if text.startswith("http://"):
prefix_len = 7
elif text.startswith("https://"):
prefix_len = 8
else:
return None
link_end = _check_domain(text[prefix_len:], True)
if link_end is None:
return None
link_end += prefix_len
while link_end < len(text) and not _isspace(text[link_end]):
link_end += 1
link_end = _autolink_delim(text, link_end)
url = text[:link_end]
return url, len(url)
# ---------------------------------------------------------------------------
# Email matching
# ---------------------------------------------------------------------------
def match_email(text: str) -> tuple[str, int] | None:
"""Match an email address (optionally prefixed by ``mailto:``/``xmpp:``)."""
pos = 0
protocol: str | None = None
if text.startswith("mailto:"):
protocol = "mailto"
pos = 7
elif text.startswith("xmpp:"):
protocol = "xmpp"
pos = 5
return match_any_email(text, pos, protocol)
def match_any_email(
text: str, pos: int, protocol: str | None
) -> tuple[str, int] | None:
"""Match an email address in *text* starting the local-part scan at *pos*.
*protocol* is ``"mailto"``, ``"xmpp"``, or ``None`` (bare address).
Returns ``(url, char_count)`` or ``None``.
"""
size = len(text)
# scan local part (before @)
start_pos = pos
while pos < size:
ch = text[pos]
if ch.isascii() and (ch.isalnum() or ch in _EMAIL_OK):
pos += 1
continue
if ch == "@":
break
return None
if pos == start_pos:
return None
# scan domain (after @)
link_end = pos + 1
np = 0
num_slash = 0
while link_end < size:
ch = text[link_end]
if ch.isascii() and ch.isalnum():
pass
elif ch == "@":
if protocol != "xmpp":
return None
elif (
ch == "."
and link_end < size - 1
and text[link_end + 1].isascii()
and text[link_end + 1].isalnum()
):
np += 1
elif ch == "/" and protocol == "xmpp" and num_slash == 0:
num_slash += 1
elif ch != "-" and ch != "_":
break
link_end += 1
if link_end < 2 or np == 0:
return None
last_ch = text[link_end - 1]
if not (last_ch.isascii() and last_ch.isalpha()) and last_ch != ".":
return None
url = "mailto:" + text[:link_end] if protocol is None else text[:link_end]
return url, link_end
|
