all messages for Emacs-related lists mirrored at yhetil.org
 help / color / mirror / code / Atom feed
blob 69f63dfbc4433a2f6589765d8b7d24a02a373a4f 84196 bytes (raw)
name: lisp/erc/erc-backend.el 	 # note: path name is non-authoritative(*)

   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
 251
 252
 253
 254
 255
 256
 257
 258
 259
 260
 261
 262
 263
 264
 265
 266
 267
 268
 269
 270
 271
 272
 273
 274
 275
 276
 277
 278
 279
 280
 281
 282
 283
 284
 285
 286
 287
 288
 289
 290
 291
 292
 293
 294
 295
 296
 297
 298
 299
 300
 301
 302
 303
 304
 305
 306
 307
 308
 309
 310
 311
 312
 313
 314
 315
 316
 317
 318
 319
 320
 321
 322
 323
 324
 325
 326
 327
 328
 329
 330
 331
 332
 333
 334
 335
 336
 337
 338
 339
 340
 341
 342
 343
 344
 345
 346
 347
 348
 349
 350
 351
 352
 353
 354
 355
 356
 357
 358
 359
 360
 361
 362
 363
 364
 365
 366
 367
 368
 369
 370
 371
 372
 373
 374
 375
 376
 377
 378
 379
 380
 381
 382
 383
 384
 385
 386
 387
 388
 389
 390
 391
 392
 393
 394
 395
 396
 397
 398
 399
 400
 401
 402
 403
 404
 405
 406
 407
 408
 409
 410
 411
 412
 413
 414
 415
 416
 417
 418
 419
 420
 421
 422
 423
 424
 425
 426
 427
 428
 429
 430
 431
 432
 433
 434
 435
 436
 437
 438
 439
 440
 441
 442
 443
 444
 445
 446
 447
 448
 449
 450
 451
 452
 453
 454
 455
 456
 457
 458
 459
 460
 461
 462
 463
 464
 465
 466
 467
 468
 469
 470
 471
 472
 473
 474
 475
 476
 477
 478
 479
 480
 481
 482
 483
 484
 485
 486
 487
 488
 489
 490
 491
 492
 493
 494
 495
 496
 497
 498
 499
 500
 501
 502
 503
 504
 505
 506
 507
 508
 509
 510
 511
 512
 513
 514
 515
 516
 517
 518
 519
 520
 521
 522
 523
 524
 525
 526
 527
 528
 529
 530
 531
 532
 533
 534
 535
 536
 537
 538
 539
 540
 541
 542
 543
 544
 545
 546
 547
 548
 549
 550
 551
 552
 553
 554
 555
 556
 557
 558
 559
 560
 561
 562
 563
 564
 565
 566
 567
 568
 569
 570
 571
 572
 573
 574
 575
 576
 577
 578
 579
 580
 581
 582
 583
 584
 585
 586
 587
 588
 589
 590
 591
 592
 593
 594
 595
 596
 597
 598
 599
 600
 601
 602
 603
 604
 605
 606
 607
 608
 609
 610
 611
 612
 613
 614
 615
 616
 617
 618
 619
 620
 621
 622
 623
 624
 625
 626
 627
 628
 629
 630
 631
 632
 633
 634
 635
 636
 637
 638
 639
 640
 641
 642
 643
 644
 645
 646
 647
 648
 649
 650
 651
 652
 653
 654
 655
 656
 657
 658
 659
 660
 661
 662
 663
 664
 665
 666
 667
 668
 669
 670
 671
 672
 673
 674
 675
 676
 677
 678
 679
 680
 681
 682
 683
 684
 685
 686
 687
 688
 689
 690
 691
 692
 693
 694
 695
 696
 697
 698
 699
 700
 701
 702
 703
 704
 705
 706
 707
 708
 709
 710
 711
 712
 713
 714
 715
 716
 717
 718
 719
 720
 721
 722
 723
 724
 725
 726
 727
 728
 729
 730
 731
 732
 733
 734
 735
 736
 737
 738
 739
 740
 741
 742
 743
 744
 745
 746
 747
 748
 749
 750
 751
 752
 753
 754
 755
 756
 757
 758
 759
 760
 761
 762
 763
 764
 765
 766
 767
 768
 769
 770
 771
 772
 773
 774
 775
 776
 777
 778
 779
 780
 781
 782
 783
 784
 785
 786
 787
 788
 789
 790
 791
 792
 793
 794
 795
 796
 797
 798
 799
 800
 801
 802
 803
 804
 805
 806
 807
 808
 809
 810
 811
 812
 813
 814
 815
 816
 817
 818
 819
 820
 821
 822
 823
 824
 825
 826
 827
 828
 829
 830
 831
 832
 833
 834
 835
 836
 837
 838
 839
 840
 841
 842
 843
 844
 845
 846
 847
 848
 849
 850
 851
 852
 853
 854
 855
 856
 857
 858
 859
 860
 861
 862
 863
 864
 865
 866
 867
 868
 869
 870
 871
 872
 873
 874
 875
 876
 877
 878
 879
 880
 881
 882
 883
 884
 885
 886
 887
 888
 889
 890
 891
 892
 893
 894
 895
 896
 897
 898
 899
 900
 901
 902
 903
 904
 905
 906
 907
 908
 909
 910
 911
 912
 913
 914
 915
 916
 917
 918
 919
 920
 921
 922
 923
 924
 925
 926
 927
 928
 929
 930
 931
 932
 933
 934
 935
 936
 937
 938
 939
 940
 941
 942
 943
 944
 945
 946
 947
 948
 949
 950
 951
 952
 953
 954
 955
 956
 957
 958
 959
 960
 961
 962
 963
 964
 965
 966
 967
 968
 969
 970
 971
 972
 973
 974
 975
 976
 977
 978
 979
 980
 981
 982
 983
 984
 985
 986
 987
 988
 989
 990
 991
 992
 993
 994
 995
 996
 997
 998
 999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
 
;;; erc-backend.el --- Backend network communication for ERC  -*- lexical-binding:t -*-

;; Copyright (C) 2004-2021 Free Software Foundation, Inc.

;; Filename: erc-backend.el
;; Author: Lawrence Mitchell <wence@gmx.li>
;; Maintainer: Amin Bandali <bandali@gnu.org>
;; Created: 2004-05-7
;; Keywords: comm, IRC, chat, client, internet

;; This file is part of GNU Emacs.

;; GNU Emacs is free software: you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation, either version 3 of the License, or
;; (at your option) any later version.

;; GNU Emacs is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;; GNU General Public License for more details.

;; You should have received a copy of the GNU General Public License
;; along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.

;;; Commentary:

;; This file defines backend network communication handlers for ERC.
;;
;; How things work:
;;
;; You define a new handler with `define-erc-response-handler'.  This
;; defines a function, a corresponding hook variable, and populates a
;; global hash table `erc-server-responses' with a map from response
;; to hook variable.  See the function documentation for more
;; information.
;;
;; Upon receiving a line from the server, `erc-parse-server-response'
;; is called on it.
;;
;; A line generally looks like:
;;
;; LINE := ':' SENDER ' ' COMMAND ' ' (COMMAND-ARGS ' ')* ':' CONTENTS
;; SENDER := Not ':' | ' '
;; COMMAND := Not ':' | ' '
;; COMMAND-ARGS := Not ':' | ' '
;;
;; This gets parsed and stuffed into an `erc-response' struct.  You
;; can access the fields of the struct with:
;;
;; COMMAND --- `erc-response.command'
;; COMMAND-ARGS --- `erc-response.command-args'
;; CONTENTS --- `erc-response.contents'
;; SENDER --- `erc-response.sender'
;; LINE --- `erc-response.unparsed'
;; TAGS --- `erc-response.tags'
;;
;; WARNING, WARNING!!
;; It's probably not a good idea to destructively modify the list
;; of command-args in your handlers, since other functions down the
;; line may well need to access the arguments too.
;;
;; That is, unless you're /absolutely/ sure that your handler doesn't
;; invoke some other function that needs to use COMMAND-ARGS, don't do
;; something like
;;
;; (while (erc-response.command-args parsed)
;;   (let ((a (pop (erc-response.command-args parsed))))
;;     ...))
;;
;; The parsed response is handed over to
;; `erc-handle-parsed-server-response', which checks whether it should
;; carry out duplicate suppression, and then runs `erc-call-hooks'.
;; `erc-call-hooks' retrieves the relevant hook variable from
;; `erc-server-responses' and runs it.
;;
;; Most handlers then destructure the parsed response in some way
;; (depending on what the handler is, the arguments have different
;; meanings), and generally display something, usually using
;; `erc-display-message'.

;;; TODO:

;; o Generalize the display-line code so that we can use it to
;;   display the stuff we send, as well as the stuff we receive.
;;   Then, move all display-related code into another backend-like
;;   file, erc-display.el, say.
;;
;; o Clean up the handlers using new display code (has to be written
;;   first).

;;; History:

;; 2004/05/10 -- Handler bodies taken out of erc.el and ported to new
;;               interface.

;; 2005-08-13 -- Moved sending commands from erc.el.

;;; Code:

(eval-when-compile (require 'cl-lib))
;; There's a fairly strong mutual dependency between erc.el and erc-backend.el.
;; Luckily, erc.el does not need erc-backend.el for macroexpansion whereas the
;; reverse is true:
(provide 'erc-backend)
(require 'erc)

;;;; Variables and options

(defvar erc-server-responses (make-hash-table :test #'equal)
  "Hash table mapping server responses to their handler hooks.")

(cl-defstruct (erc-response (:conc-name erc-response.))
  (unparsed "" :type string)
  (sender "" :type string)
  (command "" :type string)
  (command-args '() :type list)
  (contents "" :type string)
  (tags '() :type list))

;;; User data

(defvar-local erc-server-current-nick nil
  "Nickname on the current server.
Use `erc-current-nick' to access this.")

;;; Server attributes

(defvar-local erc-server-process nil
  "The process object of the corresponding server connection.")

(defvar-local erc-session-server nil
  "The server name used to connect to for this session.")

(defvar-local erc-session-connector nil
  "The function used to connect to this session (nil for the default).")

(defvar-local erc-session-port nil
  "The port used to connect to.")

(defvar-local erc-session-client-certificate nil
  "TLS client certificate used when connecting over TLS.
If non-nil, should either be a list where the first element is
the certificate key file name, and the second element is the
certificate file name itself, or t, which means that
`auth-source' will be queried for the key and the certificate.")

(defvar-local erc-server-announced-name nil
  "The name the server announced to use.")

(defvar-local erc-server-version nil
  "The name and version of the server's ircd.")

(defvar-local erc-server-parameters nil
  "Alist listing the supported server parameters.

This is only set if the server sends 005 messages saying what is
supported on the server.

Entries are of the form:
  (PARAMETER . VALUE)
or
  (PARAMETER) if no value is provided.

Some examples of possible parameters sent by servers:
CHANMODES=b,k,l,imnpst - list of supported channel modes
CHANNELLEN=50 - maximum length of channel names
CHANTYPES=#&!+ - supported channel prefixes
CHARMAPPING=rfc1459 - character mapping used for nickname and channels
KICKLEN=160 - maximum allowed kick message length
MAXBANS=30 - maximum number of bans per channel
MAXCHANNELS=10 - maximum number of channels allowed to join
NETWORK=EFnet -  the network identifier
NICKLEN=9 - maximum allowed length of nicknames
PREFIX=(ov)@+ - list of channel modes and the user prefixes if user has mode
RFC2812 - server supports RFC 2812 features
SILENCE=10 - supports the SILENCE command, maximum allowed number of entries
TOPICLEN=160 - maximum allowed topic length
WALLCHOPS - supports sending messages to all operators in a channel")

;;; Server and connection state

(defvar erc-server-ping-timer-alist nil
  "Mapping of server buffers to their specific ping timer.")

(defvar-local erc-server-connected nil
  "Non-nil if the current buffer has been used by ERC to establish
an IRC connection.

If you wish to determine whether an IRC connection is currently
active, use the `erc-server-process-alive' function instead.")

(defvar-local erc-server-reconnect-count 0
  "Number of times we have failed to reconnect to the current server.")

(defvar-local erc-server-quitting nil
  "Non-nil if the user requests a quit.")

(defvar-local erc-server-reconnecting nil
  "Non-nil if the user requests an explicit reconnect, and the
current IRC process is still alive.")
(make-obsolete-variable 'erc-server-reconnecting
                        "see `erc--server-reconnecting'" "29.1")

(defvar-local erc--server-reconnecting nil
  "Non-nil when reconnecting.")

(defvar-local erc-server-timed-out nil
  "Non-nil if the IRC server failed to respond to a ping.")

(defvar-local erc-server-banned nil
  "Non-nil if the user is denied access because of a server ban.")

(defvar-local erc-server-error-occurred nil
  "Non-nil if the user triggers some server error.")

(defvar-local erc-server-lines-sent nil
  "Line counter.")

(defvar-local erc-server-last-peers '(nil . nil)
  "Last peers used, both sender and receiver.
Those are used for /MSG destination shortcuts.")

(defvar-local erc-server-last-sent-time nil
  "Time the message was sent.
This is useful for flood protection.")

(defvar-local erc-server-last-ping-time nil
  "Time the last ping was sent.
This is useful for flood protection.")

(defvar-local erc-server-last-received-time nil
  "Time the last message was received from the server.
This is useful for detecting hung connections.")

(defvar-local erc-server-lag nil
  "Calculated server lag time in seconds.
This variable is only set in a server buffer.")

(defvar-local erc-server-filter-data nil
  "The data that arrived from the server but has not been processed yet.")

(defvar-local erc-server-duplicates (make-hash-table :test 'equal)
  "Internal variable used to track duplicate messages.")

;; From Circe
(defvar-local erc-server-processing-p nil
  "Non-nil when we're currently processing a message.

When ERC receives a private message, it sets up a new buffer for
this query.  These in turn, though, do start flyspell.  This
involves starting an external process, in which case Emacs will
wait - and when it waits, it does accept other stuff from, say,
network exceptions.  So, if someone sends you two messages
quickly after each other, ispell is started for the first, but
might take long enough for the second message to be processed
first.")

(defvar-local erc-server-flood-last-message 0
  "When we sent the last message.
See `erc-server-flood-margin' for an explanation of the flood
protection algorithm.")

(defvar-local erc-server-flood-queue nil
  "The queue of messages waiting to be sent to the server.
See `erc-server-flood-margin' for an explanation of the flood
protection algorithm.")

(defvar-local erc-server-flood-timer nil
  "The timer to resume sending.")

;;; IRC protocol and misc options

(defgroup erc-server nil
  "Parameters for dealing with IRC servers."
  :group 'erc)

(defcustom erc-server-auto-reconnect t
  "Non-nil means that ERC will attempt to reestablish broken connections.

Reconnection will happen automatically for any unexpected disconnection."
  :type 'boolean)

(defcustom erc-server-reconnect-attempts 2
  "Number of times that ERC will attempt to reestablish a broken connection.
If t, always attempt to reconnect.

This only has an effect if `erc-server-auto-reconnect' is non-nil."
  :type '(choice (const :tag "Always reconnect" t)
                 integer))

(defcustom erc-server-reconnect-timeout 1
  "Number of seconds to wait between successive reconnect attempts.

If a key is pressed while ERC is waiting, it will stop waiting."
  :type 'number)

(defcustom erc-split-line-length 440
  "The maximum length of a single message.
If a message exceeds this size, it is broken into multiple ones.

IRC allows for lines up to 512 bytes.  Two of them are CR LF.
And a typical message looks like this:

  :nicky!uhuser@host212223.dialin.fnordisp.net PRIVMSG #lazybastards :Hello!

You can limit here the maximum length of the \"Hello!\" part.
Good luck."
  :type 'integer)

(defcustom erc-coding-system-precedence '(utf-8 undecided)
  "List of coding systems to be preferred when receiving a string from the server.
This will only be consulted if the coding system in
`erc-server-coding-system' is `undecided'."
  :version "24.1"
  :type '(repeat coding-system))

(defcustom erc-server-coding-system (if (and (fboundp 'coding-system-p)
                                             (coding-system-p 'undecided)
                                             (coding-system-p 'utf-8))
                                        '(utf-8 . undecided)
                                      nil)
  "The default coding system for incoming and outgoing text.
This is either a coding system, a cons, a function, or nil.

If a cons, the encoding system for outgoing text is in the car
and the decoding system for incoming text is in the cdr.  The most
interesting use for this is to put `undecided' in the cdr.  This
means that `erc-coding-system-precedence' will be consulted, and the
first match there will be used.

If a function, it is called with the argument `target' and should
return a coding system or a cons as described above.

If you need to send non-ASCII text to people not using a client that
does decoding on its own, you must tell ERC what encoding to use.
Emacs cannot guess it, since it does not know what the people on the
other end of the line are using."
  :type '(choice (const :tag "None" nil)
                 coding-system
                 (cons (coding-system :tag "encoding" :value utf-8)
                       (coding-system :tag "decoding" :value undecided))
                 function))

(defcustom erc-encoding-coding-alist nil
  "Alist of target regexp and coding-system pairs to use.
This overrides `erc-server-coding-system' depending on the
current target as returned by `erc-default-target'.

Example: If you know that the channel #linux-ru uses the coding-system
`cyrillic-koi8', then add (\"#linux-ru\" . cyrillic-koi8) to the
alist."
  :type '(repeat (cons (regexp :tag "Target")
                       coding-system)))

(defcustom erc-server-connect-function #'erc-open-network-stream
  "Function used to initiate a connection.
It should take same arguments as `open-network-stream' does."
  :type 'function)

(defcustom erc-server-prevent-duplicates '("301")
  "Either nil or a list of strings.
Each string is a IRC message type, like PRIVMSG or NOTICE.
All Message types in that list of subjected to duplicate prevention."
  :type '(choice (const nil) (list string)))

(defcustom erc-server-duplicate-timeout 60
  "The time allowed in seconds between duplicate messages.

If two identical messages arrive within this value of one another, the second
isn't displayed."
  :type 'integer)

(defcustom erc-server-timestamp-format "%Y-%m-%d %T"
  "Timestamp format used with server response messages.
This string is processed using `format-time-string'."
  :version "24.3"
  :type 'string)

;;; Flood-related

;; Most of this is courtesy of Jorgen Schaefer and Circe
;; (https://www.nongnu.org/circe)

(defcustom erc-server-flood-margin 10
  "A margin on how much excess data we send.
The flood protection algorithm of ERC works like the one
detailed in RFC 2813, section 5.8 \"Flood control of clients\".

  * If `erc-server-flood-last-message' is less than the current
    time, set it equal.
  * While `erc-server-flood-last-message' is less than
    `erc-server-flood-margin' seconds ahead of the current
    time, send a message, and increase
    `erc-server-flood-last-message' by
    `erc-server-flood-penalty' for each message."
  :type 'integer)

(defcustom erc-server-flood-penalty 3
  "How much we penalize a message.
See `erc-server-flood-margin' for an explanation of the flood
protection algorithm."
  :type 'integer)

;; Ping handling

(defcustom erc-server-send-ping-interval 30
  "Interval of sending pings to the server, in seconds.
If this is set to nil, pinging the server is disabled."
  :type '(choice (const :tag "Disabled" nil)
                 (integer :tag "Seconds")))

(defcustom erc-server-send-ping-timeout 120
  "If the time between ping and response is greater than this, reconnect.
The time is in seconds.

This must be greater than or equal to the value for
`erc-server-send-ping-interval'.

If this is set to nil, never try to reconnect."
  :type '(choice (const :tag "Disabled" nil)
                 (integer :tag "Seconds")))

(defvar-local erc-server-ping-handler nil
  "This variable holds the periodic ping timer.")

;;;; Helper functions

;; From Circe
(defun erc-split-line (longline)
  "Return a list of lines which are not too long for IRC.
The length is specified in `erc-split-line-length'.

Currently this is called by `erc-send-input'."
  (let* ((coding (erc-coding-system-for-target nil))
         (charset (if (consp coding) (car coding) coding)))
    (with-temp-buffer
      (insert longline)
      ;; The line lengths are in octets, not characters (because these
      ;; are server protocol limits), so we have to first make the
      ;; text into bytes, then fold the bytes on "word" boundaries,
      ;; and then make the bytes into text again.
      (encode-coding-region (point-min) (point-max) charset)
      (let ((fill-column erc-split-line-length))
        (fill-region (point-min) (point-max)
                     nil t))
      (decode-coding-region (point-min) (point-max) charset)
      (split-string (buffer-string) "\n"))))

(defun erc-forward-word ()
  "Move forward one word, ignoring any subword settings.
If no `subword-mode' is active, then this is (forward-word)."
  (skip-syntax-forward "^w")
  (> (skip-syntax-forward "w") 0))

(defun erc-word-at-arg-p (pos)
  "Report whether the char after a given POS has word syntax.
If POS is out of range, the value is nil."
  (let ((c (char-after pos)))
    (if c
        (eq ?w (char-syntax c))
      nil)))

(defun erc-bounds-of-word-at-point ()
  "Return the bounds of word at point, or nil if we're not at a word.
If no `subword-mode' is active, then this is
\(bounds-of-thing-at-point 'word)."
  (if (or (erc-word-at-arg-p (point))
          (erc-word-at-arg-p (1- (point))))
      (save-excursion
        (let* ((start (progn (skip-syntax-backward "w") (point)))
               (end   (progn (skip-syntax-forward  "w") (point))))
          (cons start end)))
    nil))

;; Used by CTCP functions
(defun erc-upcase-first-word (str)
  "Upcase the first word in STR."
  (with-temp-buffer
    (insert str)
    (goto-char (point-min))
    (upcase-region (point) (progn (erc-forward-word) (point)))
    (buffer-string)))

(defun erc-server-setup-periodical-ping (buffer)
  "Set up a timer to periodically ping the current server.
The current buffer is given by BUFFER."
  (with-current-buffer buffer
    (when erc-server-ping-handler
      (cancel-timer erc-server-ping-handler))
    (when erc-server-send-ping-interval
      (setq erc-server-ping-handler (run-with-timer
                                     4 erc-server-send-ping-interval
                                     #'erc-server-send-ping
                                     buffer))

      ;; I check the timer alist for an existing timer. If one exists,
      ;; I get rid of it
      (let ((timer-tuple (assq buffer erc-server-ping-timer-alist)))
        (if timer-tuple
            ;; this buffer already has a timer. Cancel it and set the new one
            (progn
              (cancel-timer (cdr timer-tuple))
              (setf (cdr (assq buffer erc-server-ping-timer-alist)) erc-server-ping-handler))

          ;; no existing timer for this buffer. Add new one
          (add-to-list 'erc-server-ping-timer-alist
                       (cons buffer erc-server-ping-handler)))))))

(defun erc-server-process-alive (&optional buffer)
  "Return non-nil when BUFFER has an `erc-server-process' open or running."
  (with-current-buffer (or buffer (current-buffer))
    (and erc-server-process
         (processp erc-server-process)
         (memq (process-status erc-server-process) '(run open)))))

;;;; Connecting to a server
(defun erc-open-network-stream (name buffer host service &rest parameters)
  "Like `open-network-stream', but does non-blocking IO."
  (let ((p (plist-put parameters :nowait t)))
    (apply #'open-network-stream name buffer host service p)))

(defun erc-server-connect (server port buffer &optional client-certificate)
  "Perform the connection and login using the specified SERVER and PORT.
We will store server variables in the buffer given by BUFFER.
CLIENT-CERTIFICATE may optionally be used to specify a TLS client
certificate to use for authentication when connecting over
TLS (see `erc-session-client-certificate' for more details)."
  (let ((msg (erc-format-message 'connect ?S server ?p port)) process
        (args `(,(format "erc-%s-%s" server port) nil ,server ,port)))
    (when client-certificate
      (setq args `(,@args :client-certificate ,client-certificate)))
    (message "%s" msg)
    (setq process (apply erc-server-connect-function args))
    (unless (processp process)
      (error "Connection attempt failed"))
    ;; Misc server variables
    (with-current-buffer buffer
      (setq erc-server-process process)
      (setq erc-server-quitting nil)
      (setq erc-server-reconnecting nil
            erc--server-reconnecting nil)
      (setq erc-server-timed-out nil)
      (setq erc-server-banned nil)
      (setq erc-server-error-occurred nil)
      (let ((time (erc-current-time)))
        (setq erc-server-last-sent-time time)
        (setq erc-server-last-ping-time time)
        (setq erc-server-last-received-time time))
      (setq erc-server-lines-sent 0)
      ;; last peers (sender and receiver)
      (setq erc-server-last-peers '(nil . nil)))
    ;; we do our own encoding and decoding
    (when (fboundp 'set-process-coding-system)
      (set-process-coding-system process 'raw-text))
    ;; process handlers
    (set-process-sentinel process #'erc-process-sentinel)
    (set-process-filter process #'erc-server-filter-function)
    (set-process-buffer process buffer)
    (erc-log "\n\n\n********************************************\n")
    (message "%s" (erc-format-message
                   'login ?n
                   (with-current-buffer buffer (erc-current-nick))))
    ;; wait with script loading until we receive a confirmation (first
    ;; MOTD line)
    (if (eq (process-status process) 'connect)
        ;; waiting for a non-blocking connect - keep the user informed
        (erc-display-message nil nil buffer "Opening connection..\n")
      (message "%s...done" msg)
      (erc-login)) ))

(defun erc-server-reconnect ()
  "Reestablish the current IRC connection.
Make sure you are in an ERC buffer when running this."
  (let ((buffer (erc-server-buffer)))
    (unless (buffer-live-p buffer)
      (if (eq major-mode 'erc-mode)
          (setq buffer (current-buffer))
        (error "Reconnect must be run from an ERC buffer")))
    (with-current-buffer buffer
      (erc-update-mode-line)
      (erc-set-active-buffer (current-buffer))
      (setq erc-server-last-sent-time 0)
      (setq erc-server-lines-sent 0)
      (let ((erc-server-connect-function (or erc-session-connector
                                             #'erc-open-network-stream)))
        (erc-open erc-session-server erc-session-port erc-server-current-nick
                  erc-session-user-full-name t erc-session-password)))))

(defun erc-server-delayed-reconnect (buffer)
  (if (buffer-live-p buffer)
    (with-current-buffer buffer
      (erc-server-reconnect))))

(defun erc-server-filter-function (process string)
  "The process filter for the ERC server."
  (with-current-buffer (process-buffer process)
    (setq erc-server-last-received-time (erc-current-time))
    ;; If you think this is written in a weird way - please refer to the
    ;; docstring of `erc-server-processing-p'
    (if erc-server-processing-p
        (setq erc-server-filter-data
              (if erc-server-filter-data
                  (concat erc-server-filter-data string)
                string))
      ;; This will be true even if another process is spawned!
      (let ((erc-server-processing-p t))
        (setq erc-server-filter-data (if erc-server-filter-data
                                           (concat erc-server-filter-data
                                                   string)
                                         string))
        (while (and erc-server-filter-data
                    (string-match "[\n\r]+" erc-server-filter-data))
          (let ((line (substring erc-server-filter-data
                                 0 (match-beginning 0))))
            (setq erc-server-filter-data
                  (if (= (match-end 0)
                         (length erc-server-filter-data))
                      nil
                    (substring erc-server-filter-data
                               (match-end 0))))
            (erc-log-irc-protocol line nil)
            (erc-parse-server-response process line)))))))

(defun erc--server-reconnect-p (event)
  "Return non-nil when ERC should attempt to reconnect.
EVENT is the message received from the closed connection process."
  (and erc-server-auto-reconnect
       (not erc-server-banned)
       ;; make sure we don't infinitely try to reconnect, unless the
       ;; user wants that
       (or (eq erc-server-reconnect-attempts t)
           (and (integerp erc-server-reconnect-attempts)
                (< erc-server-reconnect-count
                   erc-server-reconnect-attempts)))
       (or erc-server-timed-out
           (not (string-match "^deleted" event)))
       ;; open-network-stream-nowait error for connection refused
       (if (string-match "^failed with code 111" event) 'nonblocking t)))

(defun erc-server-reconnect-p (event)
  "Return non-nil if ERC should attempt to reconnect automatically.
EVENT is the message received from the closed connection process."
  (declare (obsolete "see `erc--server-reconnect-p'" "29.1"))
  (or (with-suppressed-warnings ((obsolete erc-server-reconnecting))
        erc-server-reconnecting)
      (erc--server-reconnect-p event)))

(defun erc-process-sentinel-2 (event buffer)
  "Called when `erc-process-sentinel-1' has detected an unexpected disconnect."
  (if (not (buffer-live-p buffer))
      (erc-update-mode-line)
    (with-current-buffer buffer
      (let ((reconnect-p (erc--server-reconnect-p event)) message delay)
        (setq message (if reconnect-p 'disconnected 'disconnected-noreconnect))
        (erc-display-message nil 'error (current-buffer) message)
        (if (not reconnect-p)
            ;; terminate, do not reconnect
            (progn
              (setq erc--server-reconnecting nil)
              (erc-display-message nil 'error (current-buffer)
                                   'terminated ?e event)
              ;; Update mode line indicators
              (erc-update-mode-line)
              (set-buffer-modified-p nil))
          ;; reconnect
          (condition-case nil
              (progn
                (setq erc-server-reconnecting nil
                      erc--server-reconnecting t
                      erc-server-reconnect-count (1+ erc-server-reconnect-count))
                (setq delay erc-server-reconnect-timeout)
                (run-at-time delay nil
                             #'erc-server-delayed-reconnect buffer))
            (error (unless (integerp erc-server-reconnect-attempts)
                     (message "%s ... %s"
                              "Reconnecting until we succeed"
                              "kill the ERC server buffer to stop"))
                   (erc-server-delayed-reconnect buffer))))))))

(defun erc-process-sentinel-1 (event buffer)
  "Called when `erc-process-sentinel' has decided that we're disconnecting.
Determine whether user has quit or whether erc has been terminated.
Conditionally try to reconnect and take appropriate action."
  (with-current-buffer buffer
    (if erc-server-quitting
        ;; normal quit
        (progn
          (erc-display-message nil 'error (current-buffer) 'finished)
          ;; Update mode line indicators
          (erc-update-mode-line)
          ;; Kill server buffer if user wants it
          (set-buffer-modified-p nil)
          (when erc-kill-server-buffer-on-quit
            (kill-buffer (current-buffer))))
      ;; unexpected disconnect
      (erc-process-sentinel-2 event buffer))))

(defun erc-process-sentinel (cproc event)
  "Sentinel function for ERC process."
  (let ((buf (process-buffer cproc)))
    (when (buffer-live-p buf)
      (with-current-buffer buf
        (erc-log (format
                  "SENTINEL: proc: %S    status: %S  event: %S (quitting: %S)"
                  cproc (process-status cproc) event erc-server-quitting))
        (if (string-match "^open" event)
            ;; newly opened connection (no wait)
            (erc-login)
          ;; assume event is 'failed
          (erc-with-all-buffers-of-server cproc nil
                                          (setq erc-server-connected nil))
          (when erc-server-ping-handler
            (progn (cancel-timer erc-server-ping-handler)
                   (setq erc-server-ping-handler nil)))
          (run-hook-with-args 'erc-disconnected-hook
                              (erc-current-nick) (system-name) "")
          (dolist (buf (erc-buffer-filter (lambda () (boundp 'erc-channel-users)) cproc))
            (with-current-buffer buf
              (setq erc-channel-users (make-hash-table :test 'equal))))
          ;; Remove the prompt
          (goto-char (or (marker-position erc-input-marker) (point-max)))
          (forward-line 0)
          (erc-remove-text-properties-region (point) (point-max))
          (delete-region (point) (point-max))
          ;; Decide what to do with the buffer
          ;; Restart if disconnected
          (erc-process-sentinel-1 event buf))))))

;;;; Sending messages

(defun erc-coding-system-for-target (target)
  "Return the coding system or cons cell appropriate for TARGET.
This is determined via `erc-encoding-coding-alist' or
`erc-server-coding-system'."
  (unless target (setq target (erc-default-target)))
  (or (when target
        (let ((case-fold-search t))
          (catch 'match
            (dolist (pat erc-encoding-coding-alist)
              (when (string-match (car pat) target)
                (throw 'match (cdr pat)))))))
      (and (functionp erc-server-coding-system)
           (funcall erc-server-coding-system target))
      erc-server-coding-system))

(defun erc-decode-string-from-target (str target)
  "Decode STR as appropriate for TARGET.
This is indicated by `erc-encoding-coding-alist', defaulting to the
value of `erc-server-coding-system'."
  (unless (stringp str)
    (setq str ""))
  (let ((coding (erc-coding-system-for-target target)))
    (when (consp coding)
      (setq coding (cdr coding)))
    (when (eq coding 'undecided)
      (let ((codings (detect-coding-string str))
            (precedence erc-coding-system-precedence))
        (while (and precedence
                    (not (memq (car precedence) codings)))
          (pop precedence))
        (when precedence
          (setq coding (car precedence)))))
    (decode-coding-string str coding t)))

;; proposed name, not used by anything yet
(defun erc-send-line (text display-fn)
  "Send TEXT to the current server.  Wrapping and flood control apply.
Use DISPLAY-FN to show the results."
  (mapc (lambda (line)
          (erc-server-send line)
          (funcall display-fn))
        (erc-split-line text)))

;; From Circe, with modifications
(defun erc-server-send (string &optional forcep target)
  "Send STRING to the current server.
If FORCEP is non-nil, no flood protection is done - the string is
sent directly.  This might cause the messages to arrive in a wrong
order.

If TARGET is specified, look up encoding information for that
channel in `erc-encoding-coding-alist' or
`erc-server-coding-system'.

See `erc-server-flood-margin' for an explanation of the flood
protection algorithm."
  (erc-log (concat "erc-server-send: " string "(" (buffer-name) ")"))
  (setq erc-server-last-sent-time (erc-current-time))
  (let ((encoding (erc-coding-system-for-target target)))
    (when (consp encoding)
      (setq encoding (car encoding)))
    (if (erc-server-process-alive)
        (erc-with-server-buffer
          (let ((str (concat string "\r\n")))
            (if forcep
                (progn
                  (setq erc-server-flood-last-message
                        (+ erc-server-flood-penalty
                           erc-server-flood-last-message))
                  (erc-log-irc-protocol str 'outbound)
                  (condition-case nil
                      (progn
                        ;; Set encoding just before sending the string
                        (when (fboundp 'set-process-coding-system)
                          (set-process-coding-system erc-server-process
                                                     'raw-text encoding))
                        (process-send-string erc-server-process str))
                    ;; See `erc-server-send-queue' for full
                    ;; explanation of why we need this condition-case
                    (error nil)))
              (setq erc-server-flood-queue
                    (append erc-server-flood-queue
                            (list (cons str encoding))))
              (erc-server-send-queue (current-buffer))))
          t)
      (message "ERC: No process running")
      nil)))

(defun erc-server-send-ping (buf)
  "Send a ping to the IRC server buffer in BUF.
Additionally, detect whether the IRC process has hung."
  (if (and (buffer-live-p buf)
           (with-current-buffer buf
             erc-server-last-received-time))
      (with-current-buffer buf
        (if (and erc-server-send-ping-timeout
                 (time-less-p
                  erc-server-send-ping-timeout
                  (time-since erc-server-last-received-time)))
            (progn
              ;; if the process is hung, kill it
              (setq erc-server-timed-out t)
              (delete-process erc-server-process))
          (erc-server-send (format "PING %.0f" (erc-current-time)))))
    ;; remove timer if the server buffer has been killed
    (let ((timer (assq buf erc-server-ping-timer-alist)))
      (when timer
        (cancel-timer (cdr timer))
        (setcdr timer nil)))))

;; From Circe
(defun erc-server-send-queue (buffer)
  "Send messages in `erc-server-flood-queue'.
See `erc-server-flood-margin' for an explanation of the flood
protection algorithm."
  (when (buffer-live-p buffer)
    (with-current-buffer buffer
      (let ((now (current-time)))
        (when erc-server-flood-timer
          (cancel-timer erc-server-flood-timer)
          (setq erc-server-flood-timer nil))
        (when (time-less-p erc-server-flood-last-message now)
          (setq erc-server-flood-last-message (erc-emacs-time-to-erc-time now)))
        (while (and erc-server-flood-queue
                    (time-less-p erc-server-flood-last-message
                                 (time-add now erc-server-flood-margin)))
          (let ((msg (caar erc-server-flood-queue))
                (encoding (cdar erc-server-flood-queue)))
            (setq erc-server-flood-queue (cdr erc-server-flood-queue)
                  erc-server-flood-last-message
                  (+ erc-server-flood-last-message
                     erc-server-flood-penalty))
            (erc-log-irc-protocol msg 'outbound)
            (erc-log (concat "erc-server-send-queue: "
                             msg "(" (buffer-name buffer) ")"))
            (when (erc-server-process-alive)
              (condition-case nil
                  ;; Set encoding just before sending the string
                  (progn
                    (when (fboundp 'set-process-coding-system)
                      (set-process-coding-system erc-server-process
                                                 'raw-text encoding))
                    (process-send-string erc-server-process msg))
                ;; Sometimes the send can occur while the process is
                ;; being killed, which results in a weird SIGPIPE error.
                ;; Catch this and ignore it.
                (error nil)))))
        (when erc-server-flood-queue
          (setq erc-server-flood-timer
                (run-at-time (+ 0.2 erc-server-flood-penalty)
                             nil #'erc-server-send-queue buffer)))))))

(defun erc-message (message-command line &optional force)
  "Send LINE to the server as a privmsg or a notice.
MESSAGE-COMMAND should be either \"PRIVMSG\" or \"NOTICE\".
If the target is \",\", the last person you've got a message from will
be used.  If the target is \".\", the last person you've sent a message
to will be used."
  (cond
   ((string-match "^\\s-*\\(\\S-+\\) ?\\(.*\\)" line)
    (let ((tgt (match-string 1 line))
          (s (match-string 2 line)))
      (erc-log (format "cmd: MSG(%s): [%s] %s" message-command tgt s))
      (cond
       ((string= tgt ",")
        (if (car erc-server-last-peers)
            (setq tgt (car erc-server-last-peers))
          (setq tgt nil)))
       ((string= tgt ".")
        (if (cdr erc-server-last-peers)
            (setq tgt (cdr erc-server-last-peers))
          (setq tgt nil))))
      (cond
       (tgt
        (setcdr erc-server-last-peers tgt)
        (erc-server-send (format "%s %s :%s" message-command tgt s)
                         force))
       (t
        (erc-display-message nil 'error (current-buffer) 'no-target))))
    t)
   (t nil)))

;;; CTCP

(defun erc-send-ctcp-message (tgt l &optional force)
  "Send CTCP message L to TGT.

If TGT is nil the message is not sent.
The command must contain neither a prefix nor a trailing `\\n'.

See also `erc-server-send'."
  (let ((l (erc-upcase-first-word l)))
    (cond
     (tgt
      (erc-log (format "erc-send-CTCP-message: [%s] %s" tgt l))
      (erc-server-send (format "PRIVMSG %s :\C-a%s\C-a" tgt l)
                       force)))))

(defun erc-send-ctcp-notice (tgt l &optional force)
  "Send CTCP notice L to TGT.

If TGT is nil the message is not sent.
The command must contain neither a prefix nor a trailing `\\n'.

See also `erc-server-send'."
  (let ((l (erc-upcase-first-word l)))
    (cond
     (tgt
      (erc-log (format "erc-send-CTCP-notice: [%s] %s" tgt l))
      (erc-server-send (format "NOTICE %s :\C-a%s\C-a" tgt l)
                       force)))))

;;;; Handling responses

(defun erc-parse-tags (string)
  "Parse IRCv3 tags list in STRING to a (tag . value) alist."
  (let ((tags)
        (tag-strings (split-string string ";")))
    (dolist (tag-string tag-strings tags)
      (let ((pair (split-string tag-string "=")))
        (push (if (consp pair)
                  pair
                `(,pair))
              tags)))))

(defun erc-parse-server-response (proc string)
  "Parse and act upon a complete line from an IRC server.
PROC is the process (connection) from which STRING was received.
PROCs `process-buffer' is `current-buffer' when this function is called."
  (unless (string= string "") ;; Ignore empty strings
    (save-match-data
      (let* ((tag-list (when (eq (aref string 0) ?@)
                         (substring string 1
                                    (if (>= emacs-major-version 28)
                                        (string-search " " string)
                                      (string-match " " string)))))
             (msg (make-erc-response :unparsed string :tags (when tag-list
                                                              (erc-parse-tags
                                                               tag-list))))
             (string (if tag-list
                         (substring string (+ 1 (if (>= emacs-major-version 28)
                                                    (string-search " " string)
                                                  (string-match " " string))))
                       string))
             (posn (if (eq (aref string 0) ?:)
                       (if (>= emacs-major-version 28)
                           (string-search " " string)
                         (string-match " " string))
                     0)))

        (setf (erc-response.sender msg)
              (if (eq posn 0)
                  erc-session-server
                (substring string 1 posn)))

        (setf (erc-response.command msg)
              (let* ((bposn (string-match "[^ \n]" string posn))
                     (eposn (if (>= emacs-major-version 28)
                                (string-search " " string bposn)
                              (string-match " " string bposn))))
                (setq posn (and eposn
                                (string-match "[^ \n]" string eposn)))
                (substring string bposn eposn)))

        (while (and posn
                    (not (eq (aref string posn) ?:)))
          (push (let* ((bposn posn)
                       (eposn (if (>= emacs-major-version 28)
                                  (string-search " " string bposn)
                                (string-match " " string bposn))))
                  (setq posn (and eposn
                                  (string-match "[^ \n]" string eposn)))
                  (substring string bposn eposn))
                (erc-response.command-args msg)))
        (when posn
      (let ((str (substring string (1+ posn))))
        (push str (erc-response.command-args msg))))

    (setf (erc-response.contents msg)
          (car (erc-response.command-args msg)))

    (setf (erc-response.command-args msg)
          (nreverse (erc-response.command-args msg)))

    (erc-decode-parsed-server-response msg)

    (erc-handle-parsed-server-response proc msg)))))

(defun erc-decode-parsed-server-response (parsed-response)
  "Decode a pre-parsed PARSED-RESPONSE before it can be handled.

If there is a channel name in `erc-response.command-args', decode
`erc-response' according to this channel name and
`erc-encoding-coding-alist', or use `erc-server-coding-system'
for decoding."
  (let ((args (erc-response.command-args parsed-response))
        (decode-target nil)
        (decoded-args ()))
    (dolist (arg args nil)
      (when (string-match "^[#&].*" arg)
        (setq decode-target arg)))
    (when (stringp decode-target)
      (setq decode-target (erc-decode-string-from-target decode-target nil)))
    (setf (erc-response.unparsed parsed-response)
          (erc-decode-string-from-target
           (erc-response.unparsed parsed-response)
           decode-target))
    (setf (erc-response.sender parsed-response)
          (erc-decode-string-from-target
           (erc-response.sender parsed-response)
           decode-target))
    (setf (erc-response.command parsed-response)
          (erc-decode-string-from-target
           (erc-response.command parsed-response)
           decode-target))
    (dolist (arg (nreverse args) nil)
      (push (erc-decode-string-from-target arg decode-target)
            decoded-args))
    (setf (erc-response.command-args parsed-response) decoded-args)
    (setf (erc-response.contents parsed-response)
          (erc-decode-string-from-target
           (erc-response.contents parsed-response)
           decode-target))))

(defun erc-handle-parsed-server-response (process parsed-response)
  "Handle a pre-parsed PARSED-RESPONSE from PROCESS.

Hands off to helper functions via `erc-call-hooks'."
  (if (member (erc-response.command parsed-response)
              erc-server-prevent-duplicates)
      (let ((m (erc-response.unparsed parsed-response)))
        ;; duplicate suppression
        (if (time-less-p (or (gethash m erc-server-duplicates) 0)
                         (time-since erc-server-duplicate-timeout))
            (erc-call-hooks process parsed-response))
        (puthash m (erc-current-time) erc-server-duplicates))
    ;; Hand off to the relevant handler.
    (erc-call-hooks process parsed-response)))

(defun erc-get-hook (command)
  "Return the hook variable associated with COMMAND.

See also `erc-server-responses'."
  (gethash (format (if (numberp command) "%03i" "%s") command)
           erc-server-responses))

(defun erc-call-hooks (process message)
  "Call hooks associated with MESSAGE in PROCESS.

Finds hooks by looking in the `erc-server-responses' hash table."
  (let ((hook (or (erc-get-hook (erc-response.command message))
                  'erc-default-server-functions)))
    (run-hook-with-args-until-success hook process message)
    (erc-with-server-buffer
      (run-hook-with-args 'erc-timer-hook (erc-current-time)))))

(add-hook 'erc-default-server-functions #'erc-handle-unknown-server-response)

(defun erc-handle-unknown-server-response (proc parsed)
  "Display unknown server response's message."
  (let ((line (concat (erc-response.sender parsed)
                      " "
                      (erc-response.command parsed)
                      " "
                      (mapconcat #'identity (erc-response.command-args parsed)
                                 " "))))
    (erc-display-message parsed 'notice proc line)))


(cl-defmacro define-erc-response-handler ((name &rest aliases)
                                          &optional extra-fn-doc extra-var-doc
                                          &rest fn-body)
  "Define an ERC handler hook/function pair.
NAME is the response name as sent by the server (see the IRC RFC for
meanings).

This creates:
 - a hook variable `erc-server-NAME-functions' initialized to
   `erc-server-NAME'.
 - a function `erc-server-NAME' with body FN-BODY.

If ALIASES is non-nil, each alias in ALIASES is `defalias'ed to
`erc-server-NAME'.
Alias hook variables are created as `erc-server-ALIAS-functions' and
initialized to the same default value as `erc-server-NAME-functions'.

FN-BODY is the body of `erc-server-NAME' it may refer to the two
function arguments PROC and PARSED.

If EXTRA-FN-DOC is non-nil, it is inserted at the beginning of the
defined function's docstring.

If EXTRA-VAR-DOC is non-nil, it is inserted at the beginning of the
defined variable's docstring.

As an example:

  (define-erc-response-handler (311 WHOIS WI)
    \"Some non-generic function documentation.\"
    \"Some non-generic variable documentation.\"
    (do-stuff-with-whois proc parsed))

Would expand to:

  (prog2
      (defvar erc-server-311-functions \\='erc-server-311
        \"Some non-generic variable documentation.

  Hook called upon receiving a 311 server response.
  Each function is called with two arguments, the process associated
  with the response and the parsed response.
  See also `erc-server-311'.\")

      (defun erc-server-311 (proc parsed)
        \"Some non-generic function documentation.

  Handler for a 311 server response.
  PROC is the server process which returned the response.
  PARSED is the actual response as an `erc-response' struct.
  If you want to add responses don't modify this function, but rather
  add things to `erc-server-311-functions' instead.\"
        (do-stuff-with-whois proc parsed))

    (puthash \"311\" \\='erc-server-311-functions erc-server-responses)
    (puthash \"WHOIS\" \\='erc-server-WHOIS-functions erc-server-responses)
    (puthash \"WI\" \\='erc-server-WI-functions erc-server-responses)

    (defalias \\='erc-server-WHOIS \\='erc-server-311)
    (defvar erc-server-WHOIS-functions \\='erc-server-311
      \"Some non-generic variable documentation.

  Hook called upon receiving a WHOIS server response.

  Each function is called with two arguments, the process associated
  with the response and the parsed response.  If the function returns
  non-nil, stop processing the hook.  Otherwise, continue.

  See also `erc-server-311'.\")

    (defalias \\='erc-server-WI \\='erc-server-311)
    (defvar erc-server-WI-functions \\='erc-server-311
      \"Some non-generic variable documentation.

  Hook called upon receiving a WI server response.
  Each function is called with two arguments, the process associated
  with the response and the parsed response.  If the function returns
  non-nil, stop processing the hook.  Otherwise, continue.

  See also `erc-server-311'.\"))

\(fn (NAME &rest ALIASES) &optional EXTRA-FN-DOC EXTRA-VAR-DOC &rest FN-BODY)"
  (declare (debug (&define [&name "erc-response-handler@"
                                  (symbolp &rest symbolp)]
                           &optional sexp sexp def-body))
           (indent defun))
  (if (numberp name) (setq name (intern (format "%03i" name))))
  (setq aliases (mapcar (lambda (a)
                          (if (numberp a)
                              (format "%03i" a)
                            a))
                        aliases))
  (let* ((hook-name (intern (format "erc-server-%s-functions" name)))
         (fn-name (intern (format "erc-server-%s" name)))
         (hook-doc (format-message "\
%sHook called upon receiving a %%s server response.
Each function is called with two arguments, the process associated
with the response and the parsed response.  If the function returns
non-nil, stop processing the hook.  Otherwise, continue.

See also `%s'."
                           (if extra-var-doc
                               (concat extra-var-doc "\n\n")
                             "")
                           fn-name))
         (fn-doc (format-message "\
%sHandler for a %s server response.
PROC is the server process which returned the response.
PARSED is the actual response as an `erc-response' struct.
If you want to add responses don't modify this function, but rather
add things to `%s' instead."
                         (if extra-fn-doc
                             (concat extra-fn-doc "\n\n")
                           "")
                         name hook-name))
         (fn-alternates
          (cl-loop for alias in aliases
                   collect (intern (format "erc-server-%s" alias))))
         (var-alternates
          (cl-loop for alias in aliases
                   collect (intern (format "erc-server-%s-functions" alias)))))
    `(prog2
         ;; Normal hook variable.  The variable may already have a
         ;; value at this point, so I default to nil, and (add-hook)
         ;; unconditionally
         (defvar ,hook-name nil ,(format hook-doc name))
         (add-hook ',hook-name #',fn-name)
         ;; Handler function
         (defun ,fn-name (proc parsed)
           ,fn-doc
           (ignore proc parsed)
           ,@fn-body)

       ;; Make find-function and find-variable find them
       (put ',fn-name 'definition-name ',name)
       (put ',hook-name 'definition-name ',name)

       ;; Hash table map of responses to hook variables
       ,@(cl-loop for response in (cons name aliases)
                  for var in (cons hook-name var-alternates)
                  collect `(puthash ,(format "%s" response) ',var
                                    erc-server-responses))
       ;; Alternates.
       ;; Functions are defaliased, hook variables are defvared so we
       ;; can add hooks to one alias, but not another.
       ,@(cl-loop for fn in fn-alternates
                  for var in var-alternates
                  for a in aliases
                  nconc (list `(defalias ',fn #',fn-name)
                              `(defvar ,var #',fn-name ,(format hook-doc a))
                              `(put ',var 'definition-name ',hook-name))))))

(define-erc-response-handler (ERROR)
  "Handle an ERROR command from the server." nil
  (setq erc-server-error-occurred t)
  (erc-display-message
   parsed 'error nil 'ERROR
   ?s (erc-response.sender parsed) ?c (erc-response.contents parsed)))

(define-erc-response-handler (INVITE)
  "Handle invitation messages."
  nil
  (let ((target (car (erc-response.command-args parsed)))
        (chnl (erc-response.contents parsed)))
    (pcase-let ((`(,nick ,login ,host)
                 (erc-parse-user (erc-response.sender parsed))))
      (setq erc-invitation chnl)
      (when (string= target (erc-current-nick))
        (erc-display-message
         parsed 'notice 'active
         'INVITE ?n nick ?u login ?h host ?c chnl)))))

(define-erc-response-handler (JOIN)
  "Handle join messages."
  nil
  (let ((chnl (erc-response.contents parsed))
        (buffer nil))
    (pcase-let ((`(,nick ,login ,host)
                 (erc-parse-user (erc-response.sender parsed))))
      ;; strip the stupid combined JOIN facility (IRC 2.9)
      (if (string-match "^\\(.*\\)\^g.*$" chnl)
          (setq chnl (match-string 1 chnl)))
      (save-excursion
        (let* ((str (cond
                     ;; If I have joined a channel
                     ((erc-current-nick-p nick)
                      (setq buffer (erc-open erc-session-server erc-session-port
                                             nick erc-session-user-full-name
                                             nil nil
                                             (list chnl) chnl
                                             erc-server-process))
                      (when buffer
                        (set-buffer buffer)
                        (erc-add-default-channel chnl)
                        (erc-server-send (format "MODE %s" chnl)))
                      (erc-with-buffer (chnl proc)
                        (erc-channel-begin-receiving-names))
                      (erc-update-mode-line)
                      (run-hooks 'erc-join-hook)
                      (erc-make-notice
                       (erc-format-message 'JOIN-you ?c chnl)))
                     (t
                      (setq buffer (erc-get-buffer chnl proc))
                      (erc-make-notice
                       (erc-format-message
                        'JOIN ?n nick ?u login ?h host ?c chnl))))))
          (when buffer (set-buffer buffer))
          (erc-update-channel-member chnl nick nick t nil nil nil nil nil host login)
          ;; on join, we want to stay in the new channel buffer
          ;;(set-buffer ob)
          (erc-display-message parsed nil buffer str))))))

(define-erc-response-handler (KICK)
  "Handle kick messages received from the server." nil
  (let* ((ch (nth 0 (erc-response.command-args parsed)))
         (tgt (nth 1 (erc-response.command-args parsed)))
         (reason (erc-trim-string (erc-response.contents parsed)))
         (buffer (erc-get-buffer ch proc)))
    (pcase-let ((`(,nick ,login ,host)
                 (erc-parse-user (erc-response.sender parsed))))
      (erc-remove-channel-member buffer tgt)
      (cond
       ((string= tgt (erc-current-nick))
        (erc-display-message
         parsed 'notice buffer
         'KICK-you ?n nick ?u login ?h host ?c ch ?r reason)
        (run-hook-with-args 'erc-kick-hook buffer)
        (erc-with-buffer
            (buffer)
          (erc-remove-channel-users))
        (erc-delete-default-channel ch buffer)
        (erc-update-mode-line buffer))
       ((string= nick (erc-current-nick))
        (erc-display-message
         parsed 'notice buffer
         'KICK-by-you ?k tgt ?c ch ?r reason))
       (t (erc-display-message
             parsed 'notice buffer
             'KICK ?k tgt ?n nick ?u login ?h host ?c ch ?r reason))))))

(define-erc-response-handler (MODE)
  "Handle server mode changes." nil
  (let ((tgt (car (erc-response.command-args parsed)))
        (mode (mapconcat #'identity (cdr (erc-response.command-args parsed))
                         " ")))
    (pcase-let ((`(,nick ,login ,host)
                 (erc-parse-user (erc-response.sender parsed))))
      (erc-log (format "MODE: %s -> %s: %s" nick tgt mode))
      ;; dirty hack
      (let ((buf (cond ((erc-channel-p tgt)
                        (erc-get-buffer tgt proc))
                       ((string= tgt (erc-current-nick)) nil)
                       ((erc-active-buffer) (erc-active-buffer))
                       (t (erc-get-buffer tgt)))))
        (with-current-buffer (or buf
                                 (current-buffer))
          (erc-update-modes tgt mode nick host login))
          (if (or (string= login "") (string= host ""))
              (erc-display-message parsed 'notice buf
                                   'MODE-nick ?n nick
                                   ?t tgt ?m mode)
            (erc-display-message parsed 'notice buf
                                 'MODE ?n nick ?u login
                                 ?h host ?t tgt ?m mode)))
      (erc-banlist-update proc parsed))))

(define-erc-response-handler (NICK)
  "Handle nick change messages." nil
  (let ((nn (erc-response.contents parsed))
        bufs)
    (pcase-let ((`(,nick ,login ,host)
                 (erc-parse-user (erc-response.sender parsed))))
      (setq bufs (erc-buffer-list-with-nick nick proc))
      (erc-log (format "NICK: %s -> %s" nick nn))
      ;; if we had a query with this user, make sure future messages will be
      ;; sent to the correct nick. also add to bufs, since the user will want
      ;; to see the nick change in the query, and if it's a newly begun query,
      ;; erc-channel-users won't contain it
      (erc-buffer-filter
       (lambda ()
         (when (equal (erc-default-target) nick)
           (setq erc-default-recipients
                 (cons nn (cdr erc-default-recipients)))
           (rename-buffer nn t)         ; bug#12002
           (erc-update-mode-line)
           (cl-pushnew (current-buffer) bufs))))
      (erc-update-user-nick nick nn host nil nil login)
      (cond
       ((string= nick (erc-current-nick))
        (cl-pushnew (erc-server-buffer) bufs)
        (erc-set-current-nick nn)
        (erc-update-mode-line)
        (setq erc-nick-change-attempt-count 0)
        (setq erc-default-nicks (if (consp erc-nick) erc-nick (list erc-nick)))
        (erc-display-message
         parsed 'notice bufs
         'NICK-you ?n nick ?N nn)
        (run-hook-with-args 'erc-nick-changed-functions nn nick))
       (t
        (erc-handle-user-status-change 'nick (list nick login host) (list nn))
        (erc-display-message parsed 'notice bufs 'NICK ?n nick
                             ?u login ?h host ?N nn))))))

(define-erc-response-handler (PART)
  "Handle part messages." nil
  (let* ((chnl (car (erc-response.command-args parsed)))
         (reason (erc-trim-string (erc-response.contents parsed)))
         (buffer (erc-get-buffer chnl proc)))
    (pcase-let ((`(,nick ,login ,host)
                 (erc-parse-user (erc-response.sender parsed))))
      (erc-remove-channel-member buffer nick)
      (erc-display-message parsed 'notice buffer
                           'PART ?n nick ?u login
                           ?h host ?c chnl ?r (or reason ""))
      (when (string= nick (erc-current-nick))
        (run-hook-with-args 'erc-part-hook buffer)
        (erc-with-buffer
            (buffer)
          (erc-remove-channel-users))
        (erc-delete-default-channel chnl buffer)
        (erc-update-mode-line buffer)
        (when erc-kill-buffer-on-part
          (kill-buffer buffer))))))

(define-erc-response-handler (PING)
  "Handle ping messages." nil
  (let ((pinger (car (erc-response.command-args parsed))))
    (erc-log (format "PING: %s" pinger))
    ;; ping response to the server MUST be forced, or you can lose big
    (erc-server-send (format "PONG :%s" pinger) t)
    (when erc-verbose-server-ping
      (erc-display-message
       parsed 'error proc
       'PING ?s (erc-time-diff erc-server-last-ping-time (erc-current-time))))
    (setq erc-server-last-ping-time (erc-current-time))))

(define-erc-response-handler (PONG)
  "Handle pong messages." nil
  (let ((time (string-to-number (erc-response.contents parsed))))
    (when (> time 0)
      (setq erc-server-lag (erc-time-diff time nil))
      (when erc-verbose-server-ping
        (erc-display-message
         parsed 'notice proc 'PONG
         ?h (car (erc-response.command-args parsed)) ?i erc-server-lag
         ?s (if (/= erc-server-lag 1) "s" "")))
      (erc-update-mode-line))))

(define-erc-response-handler (PRIVMSG NOTICE)
  "Handle private messages, including messages in channels." nil
  (let ((sender-spec (erc-response.sender parsed))
        (cmd (erc-response.command parsed))
        (tgt (car (erc-response.command-args parsed)))
        (msg (erc-response.contents parsed)))
    (if (or (erc-ignored-user-p sender-spec)
            (erc-ignored-reply-p msg tgt proc))
        (when erc-minibuffer-ignored
          (message "Ignored %s from %s to %s" cmd sender-spec tgt))
      (let* ((sndr (erc-parse-user sender-spec))
             (nick (nth 0 sndr))
             (login (nth 1 sndr))
             (host (nth 2 sndr))
             (msgp (string= cmd "PRIVMSG"))
             (noticep (string= cmd "NOTICE"))
             ;; S.B. downcase *both* tgt and current nick
             (privp (erc-current-nick-p tgt))
             s buffer
             fnick)
        (setf (erc-response.contents parsed) msg)
        (setq buffer (erc-get-buffer (if privp nick tgt) proc))
        (when buffer
          (with-current-buffer buffer
            ;; update the chat partner info.  Add to the list if private
            ;; message.  We will accumulate private identities indefinitely
            ;; at this point.
            (erc-update-channel-member (if privp nick tgt) nick nick
                                       privp nil nil nil nil nil host login nil nil t)
            (let ((cdata (erc-get-channel-user nick)))
              (setq fnick (funcall erc-format-nick-function
                                   (car cdata) (cdr cdata))))))
        (cond
         ((erc-is-message-ctcp-p msg)
          (setq s (if msgp
                      (erc-process-ctcp-query proc parsed nick login host)
                    (erc-process-ctcp-reply proc parsed nick login host
                                            (match-string 1 msg)))))
         (t
          (setcar erc-server-last-peers nick)
          (setq s (erc-format-privmessage
                   (or fnick nick) msg
                   ;; If buffer is a query buffer,
                   ;; format the nick as for a channel.
                   (and (not (and buffer
                                  (erc-query-buffer-p buffer)
                                  erc-format-query-as-channel-p))
                        privp)
                   msgp))))
        (when s
          (if (and noticep privp)
              (progn
                (run-hook-with-args 'erc-echo-notice-always-hook
                                    s parsed buffer nick)
                (run-hook-with-args-until-success
                 'erc-echo-notice-hook s parsed buffer nick))
            (erc-display-message parsed nil buffer s)))
        (when (string= cmd "PRIVMSG")
          (erc-auto-query proc parsed))))))

;; FIXME: need clean way of specifying extra hooks in
;; define-erc-response-handler.
(add-hook 'erc-server-PRIVMSG-functions #'erc-auto-query)

(define-erc-response-handler (QUIT)
  "Another user has quit IRC." nil
  (let ((reason (erc-response.contents parsed))
        bufs)
    (pcase-let ((`(,nick ,login ,host)
                 (erc-parse-user (erc-response.sender parsed))))
      (setq bufs (erc-buffer-list-with-nick nick proc))
      (erc-remove-user nick)
      (setq reason (erc-wash-quit-reason reason nick login host))
      (erc-display-message parsed 'notice bufs
                           'QUIT ?n nick ?u login
                           ?h host ?r reason))))

(define-erc-response-handler (TOPIC)
  "The channel topic has changed." nil
  (let* ((ch (car (erc-response.command-args parsed)))
         (topic (erc-trim-string (erc-response.contents parsed)))
         (time (format-time-string erc-server-timestamp-format)))
    (pcase-let ((`(,nick ,login ,host)
                 (erc-parse-user (erc-response.sender parsed))))
      (erc-update-channel-member ch nick nick nil nil nil nil nil nil host login)
      (erc-update-channel-topic ch (format "%s\C-o (%s, %s)" topic nick time))
      (erc-display-message parsed 'notice (erc-get-buffer ch proc)
                           'TOPIC ?n nick ?u login ?h host
                           ?c ch ?T topic))))

(define-erc-response-handler (WALLOPS)
  "Display a WALLOPS message." nil
  (let ((message (erc-response.contents parsed)))
    (pcase-let ((`(,nick ,_login ,_host)
                 (erc-parse-user (erc-response.sender parsed))))
      (erc-display-message
       parsed 'notice nil
       'WALLOPS ?n nick ?m message))))

(define-erc-response-handler (001)
  "Set `erc-server-current-nick' to reflect server settings.
Then display the welcome message."
  nil
  (erc-set-current-nick (car (erc-response.command-args parsed)))
  (erc-update-mode-line)                ; needed here?
  (setq erc-nick-change-attempt-count 0)
  (setq erc-default-nicks (if (consp erc-nick) erc-nick (list erc-nick)))
  (erc-display-message
   parsed 'notice 'active (erc-response.contents parsed)))

(define-erc-response-handler (MOTD 002 003 371 372 374 375)
  "Display the server's message of the day." nil
  (erc-handle-login)
  (erc-display-message
   parsed 'notice (if erc-server-connected 'active proc)
   (erc-response.contents parsed)))

(define-erc-response-handler (376 422)
  "End of MOTD/MOTD is missing." nil
  (erc-server-MOTD proc parsed)
  (erc-connection-established proc parsed))

(define-erc-response-handler (004)
  "Display the server's identification." nil
  (pcase-let ((`(,server-name ,server-version)
               (cdr (erc-response.command-args parsed))))
    (setq erc-server-version server-version)
    (setq erc-server-announced-name server-name)
    (erc-update-mode-line-buffer (process-buffer proc))
    (erc-display-message
     parsed 'notice proc
     's004 ?s server-name ?v server-version
     ?U (nth 3 (erc-response.command-args parsed))
     ?C (nth 4 (erc-response.command-args parsed)))))

(define-erc-response-handler (005)
  "Set the variable `erc-server-parameters' and display the received message.

According to RFC 2812, suggests alternate servers on the network.
Many servers, however, use this code to show which parameters they have set,
for example, the network identifier, maximum allowed topic length, whether
certain commands are accepted and more.  See documentation for
`erc-server-parameters' for more information on the parameters sent.

A server may send more than one 005 message."
  nil
  (let ((line (mapconcat #'identity
                         (setf (erc-response.command-args parsed)
                               (cdr (erc-response.command-args parsed)))
                         " ")))
    (while (erc-response.command-args parsed)
      (let ((section (pop (erc-response.command-args parsed))))
        ;; fill erc-server-parameters
        (when (string-match "^\\([A-Z]+\\)=\\(.*\\)$\\|^\\([A-Z]+\\)$"
                            section)
          (add-to-list 'erc-server-parameters
                       `(,(or (match-string 1 section)
                              (match-string 3 section))
                         .
                         ,(match-string 2 section))))))
    (erc-display-message parsed 'notice proc line)))

(define-erc-response-handler (221)
  "Display the current user modes." nil
  (let* ((nick (car (erc-response.command-args parsed)))
         (modes (mapconcat #'identity
                           (cdr (erc-response.command-args parsed)) " ")))
    (erc-set-modes nick modes)
    (erc-display-message parsed 'notice 'active 's221 ?n nick ?m modes)))

(define-erc-response-handler (252)
  "Display the number of IRC operators online." nil
  (erc-display-message parsed 'notice 'active 's252
                       ?i (cadr (erc-response.command-args parsed))))

(define-erc-response-handler (253)
  "Display the number of unknown connections." nil
  (erc-display-message parsed 'notice 'active 's253
                       ?i (cadr (erc-response.command-args parsed))))

(define-erc-response-handler (254)
  "Display the number of channels formed." nil
  (erc-display-message parsed 'notice 'active 's254
                       ?i (cadr (erc-response.command-args parsed))))

(define-erc-response-handler (250 251 255 256 257 258 259 265 266 377 378)
  "Generic display of server messages as notices.

See `erc-display-server-message'." nil
  (erc-display-server-message proc parsed))

(define-erc-response-handler (275)
  "Display secure connection message." nil
  (pcase-let ((`(,nick ,_user ,_message)
               (cdr (erc-response.command-args parsed))))
    (erc-display-message
     parsed 'notice 'active 's275
     ?n nick
     ?m (mapconcat #'identity (cddr (erc-response.command-args parsed))
                   " "))))

(define-erc-response-handler (290)
  "Handle dancer-ircd CAPAB messages." nil nil)

(define-erc-response-handler (301)
  "AWAY notice." nil
  (erc-display-message parsed 'notice 'active 's301
                       ?n (cadr (erc-response.command-args parsed))
                       ?r (erc-response.contents parsed)))

(define-erc-response-handler (303)
  "ISON reply" nil
  (erc-display-message parsed 'notice 'active 's303
                       ?n (cadr (erc-response.command-args parsed))))

(define-erc-response-handler (305)
  "Return from AWAYness." nil
  (erc-process-away proc nil)
  (erc-display-message parsed 'notice 'active
                       's305 ?m (erc-response.contents parsed)))

(define-erc-response-handler (306)
  "Set AWAYness." nil
  (erc-process-away proc t)
  (erc-display-message parsed 'notice 'active
                       's306 ?m (erc-response.contents parsed)))

(define-erc-response-handler (307)
  "Display nick-identified message." nil
  (pcase-let ((`(,nick ,_user ,_message)
               (cdr (erc-response.command-args parsed))))
    (erc-display-message
     parsed 'notice 'active 's307
     ?n nick
     ?m (mapconcat #'identity (cddr (erc-response.command-args parsed))
                   " "))))

(define-erc-response-handler (311 314)
  "WHOIS/WHOWAS notices." nil
  (let ((fname (erc-response.contents parsed))
        (catalog-entry (intern (format "s%s" (erc-response.command parsed)))))
    (pcase-let ((`(,nick ,user ,host)
                 (cdr (erc-response.command-args parsed))))
      (erc-update-user-nick nick nick host nil fname user)
      (erc-display-message
       parsed 'notice 'active catalog-entry
       ?n nick ?f fname ?u user ?h host))))

(define-erc-response-handler (312)
  "Server name response in WHOIS." nil
  (pcase-let ((`(,nick ,server-host)
              (cdr (erc-response.command-args parsed))))
    (erc-display-message
     parsed 'notice 'active 's312
     ?n nick ?s server-host ?c (erc-response.contents parsed))))

(define-erc-response-handler (313)
  "IRC Operator response in WHOIS." nil
  (erc-display-message
   parsed 'notice 'active 's313
   ?n (cadr (erc-response.command-args parsed))))

(define-erc-response-handler (315 318 323 369)
  ;; 315 - End of WHO
  ;; 318 - End of WHOIS list
  ;; 323 - End of channel LIST
  ;; 369 - End of WHOWAS
  "End of WHO/WHOIS/LIST/WHOWAS notices." nil
  (ignore proc parsed))

(define-erc-response-handler (317)
  "IDLE notice." nil
  (pcase-let ((`(,nick ,seconds-idle ,on-since ,time)
               (cdr (erc-response.command-args parsed))))
    (setq time (when on-since
                 (format-time-string erc-server-timestamp-format
                                     (string-to-number on-since))))
    (erc-update-user-nick nick nick nil nil nil
                          (and time (format "on since %s" time)))
    (if time
        (erc-display-message
         parsed 'notice 'active 's317-on-since
         ?n nick ?i (erc-sec-to-time (string-to-number seconds-idle)) ?t time)
      (erc-display-message
       parsed 'notice 'active 's317
       ?n nick ?i (erc-sec-to-time (string-to-number seconds-idle))))))

(define-erc-response-handler (319)
  "Channel names in WHOIS response." nil
  (erc-display-message
   parsed 'notice 'active 's319
   ?n (cadr (erc-response.command-args parsed))
   ?c (erc-response.contents parsed)))

(define-erc-response-handler (320)
  "Identified user in WHOIS." nil
  (erc-display-message
   parsed 'notice 'active 's320
   ?n (cadr (erc-response.command-args parsed))))

(define-erc-response-handler (321)
  "LIST header." nil
  (setq erc-channel-list nil))

(defun erc-server-321-message (proc parsed)
  "Display a message for the 321 event."
  (erc-display-message parsed 'notice proc 's321)
  nil)
(add-hook 'erc-server-321-functions #'erc-server-321-message t)

(define-erc-response-handler (322)
  "LIST notice." nil
  (let ((topic (erc-response.contents parsed)))
    (pcase-let ((`(,channel ,_num-users)
                 (cdr (erc-response.command-args parsed))))
      (add-to-list 'erc-channel-list (list channel))
      (erc-update-channel-topic channel topic))))

(defun erc-server-322-message (proc parsed)
  "Display a message for the 322 event."
  (let ((topic (erc-response.contents parsed)))
    (pcase-let ((`(,channel ,num-users)
                 (cdr (erc-response.command-args parsed))))
      (erc-display-message
       parsed 'notice proc 's322
       ?c channel ?u num-users ?t (or topic "")))))
(add-hook 'erc-server-322-functions #'erc-server-322-message t)

(define-erc-response-handler (324)
  "Channel or nick modes." nil
  (let ((channel (cadr (erc-response.command-args parsed)))
        (modes (mapconcat #'identity (cddr (erc-response.command-args parsed))
                          " ")))
    (erc-set-modes channel modes)
    (erc-display-message
     parsed 'notice (erc-get-buffer channel proc)
     's324 ?c channel ?m modes)))

(define-erc-response-handler (328)
  "Channel URL." nil
  (let ((channel (cadr (erc-response.command-args parsed)))
        (url (erc-response.contents parsed)))
    (erc-display-message parsed 'notice (erc-get-buffer channel proc)
                         's328 ?c channel ?u url)))

(define-erc-response-handler (329)
  "Channel creation date." nil
  (let ((channel (cadr (erc-response.command-args parsed)))
        (time (string-to-number
               (nth 2 (erc-response.command-args parsed)))))
    (erc-display-message
     parsed 'notice (erc-get-buffer channel proc)
     's329 ?c channel ?t (format-time-string erc-server-timestamp-format
                                             time))))

(define-erc-response-handler (330)
  "Nick is authed as (on Quakenet network)." nil
  ;; FIXME: I don't know what the magic numbers mean.  Mummy, make
  ;; the magic numbers go away.
  ;; No seriously, I have no clue about the format of this command,
  ;; and don't sit on Quakenet, so can't test.  Originally we had:
  ;; nick == (aref parsed 3)
  ;; authaccount == (aref parsed 4)
  ;; authmsg == (aref parsed 5)
  ;; The guesses below are, well, just that. -- Lawrence 2004/05/10
  (let ((nick (cadr (erc-response.command-args parsed)))
        (authaccount (nth 2 (erc-response.command-args parsed)))
        (authmsg (erc-response.contents parsed)))
    (erc-display-message parsed 'notice 'active 's330
                         ?n nick ?a authmsg ?i authaccount)))

(define-erc-response-handler (331)
  "No topic set for channel." nil
  (let ((channel (cadr (erc-response.command-args parsed))))
    (erc-display-message parsed 'notice (erc-get-buffer channel proc)
                         's331 ?c channel)))

(define-erc-response-handler (332)
  "TOPIC notice." nil
  (let ((channel (cadr (erc-response.command-args parsed)))
        (topic (erc-response.contents parsed)))
    (erc-update-channel-topic channel topic)
    (erc-display-message parsed 'notice (erc-get-buffer channel proc)
                         's332 ?c channel ?T topic)))

(define-erc-response-handler (333)
  "Who set the topic, and when." nil
  (pcase-let ((`(,channel ,nick ,time)
               (cdr (erc-response.command-args parsed))))
    (setq time (format-time-string erc-server-timestamp-format
                                   (string-to-number time)))
    (erc-update-channel-topic channel
                              (format "\C-o (%s, %s)" nick time)
                              'append)
    (erc-display-message parsed 'notice (erc-get-buffer channel proc)
                         's333 ?c channel ?n nick ?t time)))

(define-erc-response-handler (341)
  "Let user know when an INVITE attempt has been sent successfully."
  nil
  (pcase-let ((`(,nick ,channel)
               (cdr (erc-response.command-args parsed))))
    (erc-display-message parsed 'notice (erc-get-buffer channel proc)
                         's341 ?n nick ?c channel)))

(define-erc-response-handler (352)
  "WHO notice." nil
  (pcase-let ((`(,channel ,user ,host ,_server ,nick ,away-flag)
               (cdr (erc-response.command-args parsed))))
    (let ((full-name (erc-response.contents parsed)))
      (when (string-match "\\(^[0-9]+ \\)\\(.*\\)$" full-name)
        (setq full-name (match-string 2 full-name)))
      (erc-update-channel-member channel nick nick nil nil nil nil nil nil host user full-name)
      (erc-display-message parsed 'notice 'active 's352
                           ?c channel ?n nick ?a away-flag
                           ?u user ?h host ?f full-name))))

(define-erc-response-handler (353)
  "NAMES notice." nil
  (let ((channel (nth 2 (erc-response.command-args parsed)))
        (users (erc-response.contents parsed)))
    (erc-display-message parsed 'notice (or (erc-get-buffer channel proc)
                                            'active)
                         's353 ?c channel ?u users)
    (erc-with-buffer (channel proc)
      (erc-channel-receive-names users))))

(define-erc-response-handler (366)
  "End of NAMES." nil
  (erc-with-buffer ((cadr (erc-response.command-args parsed)) proc)
    (erc-channel-end-receiving-names)))

(define-erc-response-handler (367)
  "Channel ban list entries." nil
  (pcase-let ((`(,channel ,banmask ,setter ,time)
               (cdr (erc-response.command-args parsed))))
    ;; setter and time are not standard
    (if setter
        (erc-display-message parsed 'notice 'active 's367-set-by
                             ?c channel
                             ?b banmask
                             ?s setter
                             ?t (or time ""))
      (erc-display-message parsed 'notice 'active 's367
                           ?c channel
                           ?b banmask))))

(define-erc-response-handler (368)
  "End of channel ban list." nil
  (let ((channel (cadr (erc-response.command-args parsed))))
    (erc-display-message parsed 'notice 'active 's368
                         ?c channel)))

(define-erc-response-handler (379)
  "Forwarding to another channel." nil
  ;; FIXME: Yet more magic numbers in original code, I'm guessing this
  ;; command takes two arguments, and doesn't have any "contents". --
  ;; Lawrence 2004/05/10
  (pcase-let ((`(,from ,to)
               (cdr (erc-response.command-args parsed))))
    (erc-display-message parsed 'notice 'active
                         's379 ?c from ?f to)))

(define-erc-response-handler (391)
  "Server's time string." nil
  (erc-display-message
   parsed 'notice 'active
   's391 ?s (cadr (erc-response.command-args parsed))
   ?t (nth 2 (erc-response.command-args parsed))))

(define-erc-response-handler (401)
  "No such nick/channel." nil
  (let ((nick/channel (cadr (erc-response.command-args parsed))))
    (when erc-whowas-on-nosuchnick
      (erc-log (format "cmd: WHOWAS: %s" nick/channel))
      (erc-server-send (format "WHOWAS %s 1" nick/channel)))
    (erc-display-message parsed '(notice error) 'active
                         's401 ?n nick/channel)))

(define-erc-response-handler (403)
  "No such channel." nil
  (erc-display-message parsed '(notice error) 'active
                       's403 ?c (cadr (erc-response.command-args parsed))))

(define-erc-response-handler (404)
  "Cannot send to channel." nil
  (erc-display-message parsed '(notice error) 'active
                       's404 ?c (cadr (erc-response.command-args parsed))))


(define-erc-response-handler (405)
  "Can't join that many channels." nil
  (erc-display-message parsed '(notice error) 'active
                       's405 ?c (cadr (erc-response.command-args parsed))))

(define-erc-response-handler (406)
  "No such nick." nil
  (erc-display-message parsed '(notice error) 'active
                       's406 ?n (cadr (erc-response.command-args parsed))))

(define-erc-response-handler (412)
  "No text to send." nil
  (erc-display-message parsed '(notice error) 'active 's412))

(define-erc-response-handler (421)
  "Unknown command." nil
  (erc-display-message parsed '(notice error) 'active 's421
                       ?c (cadr (erc-response.command-args parsed))))

(define-erc-response-handler (432)
  "Bad nick." nil
  (erc-display-message parsed '(notice error) 'active 's432
                       ?n (cadr (erc-response.command-args parsed))))

(define-erc-response-handler (433)
  "Login-time \"nick in use\"." nil
  (erc-nickname-in-use (cadr (erc-response.command-args parsed))
                       "already in use"))

(define-erc-response-handler (437)
  "Nick temporarily unavailable (on IRCnet)." nil
  (let ((nick/channel (cadr (erc-response.command-args parsed))))
    (unless (erc-channel-p nick/channel)
      (erc-nickname-in-use nick/channel "temporarily unavailable"))))

(define-erc-response-handler (442)
  "Not on channel." nil
  (erc-display-message parsed '(notice error) 'active 's442
                       ?c (cadr (erc-response.command-args parsed))))

(define-erc-response-handler (461)
  "Not enough parameters for command." nil
  (erc-display-message parsed '(notice error)  'active 's461
                       ?c (cadr (erc-response.command-args parsed))
                       ?m (erc-response.contents parsed)))

(define-erc-response-handler (465)
  "You are banned from this server." nil
  (setq erc-server-banned t)
  ;; show the server's message, as a reason might be provided
  (erc-display-error-notice
   parsed
   (erc-response.contents parsed)))

(define-erc-response-handler (474)
  "Banned from channel errors." nil
  (erc-display-message parsed '(notice error) nil
                       (intern (format "s%s"
                                       (erc-response.command parsed)))
                       ?c (cadr (erc-response.command-args parsed))))

(define-erc-response-handler (475)
  "Channel key needed." nil
  (erc-display-message parsed '(notice error) nil 's475
                       ?c (cadr (erc-response.command-args parsed)))
  (when erc-prompt-for-channel-key
    (let ((channel (cadr (erc-response.command-args parsed)))
          (key (read-from-minibuffer
                (format "Channel %s is mode +k.  Enter key (RET to cancel): "
                        (cadr (erc-response.command-args parsed))))))
      (when (and key (> (length key) 0))
          (erc-cmd-JOIN channel key)))))

(define-erc-response-handler (477)
  "Channel doesn't support modes." nil
  (let ((channel (cadr (erc-response.command-args parsed)))
        (message (erc-response.contents parsed)))
    (erc-display-message parsed 'notice (erc-get-buffer channel proc)
                         (format "%s: %s" channel message))))

(define-erc-response-handler (482)
  "You need to be a channel operator to do that." nil
  (let ((channel (cadr (erc-response.command-args parsed)))
        (message (erc-response.contents parsed)))
    (erc-display-message parsed '(notice error) 'active 's482
                         ?c channel ?m message)))

(define-erc-response-handler (671)
  "Secure connection response in WHOIS." nil
  (let ((nick (cadr (erc-response.command-args parsed)))
        (securemsg (erc-response.contents parsed)))
    (erc-display-message parsed 'notice 'active 's671
                         ?n nick ?a securemsg)))

(define-erc-response-handler (431 445 446 451 462 463 464 481 483 484 485
                                  491 501 502)
  ;; 431 - No nickname given
  ;; 445 - SUMMON has been disabled
  ;; 446 - USERS has been disabled
  ;; 451 - You have not registered
  ;; 462 - Unauthorized command (already registered)
  ;; 463 - Your host isn't among the privileged
  ;; 464 - Password incorrect
  ;; 481 - Need IRCop privileges
  ;; 483 - You can't kill a server!
  ;; 484 - Your connection is restricted!
  ;; 485 - You're not the original channel operator
  ;; 491 - No O-lines for your host
  ;; 501 - Unknown MODE flag
  ;; 502 - Cannot change mode for other users
  "Generic display of server error messages.

See `erc-display-error-notice'." nil
  (erc-display-error-notice
   parsed
   (intern (format "s%s" (erc-response.command parsed)))))

;; FIXME: These are yet to be implemented, they're just stubs for now
;; -- Lawrence 2004/05/12

;; response numbers left here for reference

;; (define-erc-response-handler (323 364 365 381 382 392 393 394 395
;;                               200 201 202 203 204 205 206 208 209 211 212 213
;;                               214 215 216 217 218 219 241 242 243 244 249 261
;;                               262 302 342 351 402 407 409 411 413 414 415
;;                               423 424 436 441 443 444 467 471 472 473 KILL)
;;   nil nil
;;   (ignore proc parsed))

(provide 'erc-backend)

;;; erc-backend.el ends here

debug log:

solving 69f63dfbc4 ...
found 69f63dfbc4 in https://git.savannah.gnu.org/cgit/emacs.git

(*) Git path names are given by the tree(s) the blob belongs to.
    Blobs themselves have no identifier aside from the hash of its contents.^

Code repositories for project(s) associated with this external index

	https://git.savannah.gnu.org/cgit/emacs.git
	https://git.savannah.gnu.org/cgit/emacs/org-mode.git

This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.