summaryrefslogtreecommitdiffstats
path: root/unix/tkUnixSelect.c
blob: 896e897e76c586715cf99229534c3cc99be7ba29 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
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
/*
 * tkUnixSelect.c --
 *
 *	This file contains X specific routines for manipulating selections.
 *
 * Copyright (c) 1995-1997 Sun Microsystems, Inc.
 *
 * See the file "license.terms" for information on usage and redistribution of
 * this file, and for a DISCLAIMER OF ALL WARRANTIES.
 */

#include "tkInt.h"
#include "tkSelect.h"

typedef struct ConvertInfo {
    int offset;			/* The starting byte offset into the selection
				 * for the next chunk; -1 means all data has
				 * been transferred for this conversion. -2
				 * means only the final zero-length transfer
				 * still has to be done. Otherwise it is the
				 * offset of the next chunk of data to
				 * transfer. */
    Tcl_EncodingState state;	/* The encoding state needed across chunks. */
    char buffer[4];		/* A buffer to hold part of a UTF character
				 * that is split across chunks.*/
} ConvertInfo;

/*
 * When handling INCR-style selection retrievals, the selection owner uses the
 * following data structure to communicate between the ConvertSelection
 * function and TkSelPropProc.
 */

typedef struct IncrInfo {
    TkWindow *winPtr;		/* Window that owns selection. */
    Atom selection;		/* Selection that is being retrieved. */
    Atom *multAtoms;		/* Information about conversions to perform:
				 * one or more pairs of (target, property).
				 * This either points to a retrieved property
				 * (for MULTIPLE retrievals) or to a static
				 * array. */
    unsigned long numConversions;
				/* Number of entries in converts (same as # of
				 * pairs in multAtoms). */
    ConvertInfo *converts;	/* One entry for each pair in multAtoms. This
				 * array is malloc-ed. */
    char **tempBufs;		/* One pointer for each pair in multAtoms;
				 * each pointer is either NULL, or it points
				 * to a small bit of character data that was
				 * left over from the previous chunk. */
    Tcl_EncodingState *state;	/* One state info per pair in multAtoms: State
				 * info for encoding conversions that span
				 * multiple buffers. */
    int *flags;			/* One state flag per pair in multAtoms:
				 * Encoding flags, set to TCL_ENCODING_START
				 * at the beginning of an INCR transfer. */
    int numIncrs;		/* Number of entries in converts that aren't
				 * -1 (i.e. # of INCR-mode transfers not yet
				 * completed). */
    Tcl_TimerToken timeout;	/* Token for timer function. */
    int idleTime;		/* Number of seconds since we heard anything
				 * from the selection requestor. */
    Window reqWindow;		/* Requestor's window id. */
    Time time;			/* Timestamp corresponding to selection at
				 * beginning of request; used to abort
				 * transfer if selection changes. */
    struct IncrInfo *nextPtr;	/* Next in list of all INCR-style retrievals
				 * currently pending. */
} IncrInfo;

typedef struct ThreadSpecificData {
    IncrInfo *pendingIncrs;	/* List of all incr structures currently
				 * active. */
} ThreadSpecificData;
static Tcl_ThreadDataKey dataKey;

/*
 * Largest property that we'll accept when sending or receiving the selection:
 */

#define MAX_PROP_WORDS 100000

static TkSelRetrievalInfo *pendingRetrievals = NULL;
				/* List of all retrievals currently being
				 * waited for. */

/*
 * Forward declarations for functions defined in this file:
 */

static void		ConvertSelection(TkWindow *winPtr,
			    XSelectionRequestEvent *eventPtr);
static void		IncrTimeoutProc(ClientData clientData);
static void		SelCvtFromX32(long *propPtr, int numValues, Atom type,
			    Tk_Window tkwin, Tcl_DString *dsPtr);
static void		SelCvtFromX8(char *propPtr, int numValues, Atom type,
			    Tk_Window tkwin, Tcl_DString *dsPtr);
static long *		SelCvtToX(char *string, Atom type, Tk_Window tkwin,
			    int *numLongsPtr);
static int		SelectionSize(TkSelHandler *selPtr);
static void		SelRcvIncrProc(ClientData clientData,
			    XEvent *eventPtr);
static void		SelTimeoutProc(ClientData clientData);

/*
 *----------------------------------------------------------------------
 *
 * TkSelGetSelection --
 *
 *	Retrieve the specified selection from another process.
 *
 * Results:
 *	The return value is a standard Tcl return value. If an error occurs
 *	(such as no selection exists) then an error message is left in the
 *	interp's result.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

int
TkSelGetSelection(
    Tcl_Interp *interp,		/* Interpreter to use for reporting errors. */
    Tk_Window tkwin,		/* Window on whose behalf to retrieve the
				 * selection (determines display from which to
				 * retrieve). */
    Atom selection,		/* Selection to retrieve. */
    Atom target,		/* Desired form in which selection is to be
				 * returned. */
    Tk_GetSelProc *proc,	/* Function to call to process the selection,
				 * once it has been retrieved. */
    ClientData clientData)	/* Arbitrary value to pass to proc. */
{
    TkSelRetrievalInfo retr;
    TkWindow *winPtr = (TkWindow *) tkwin;
    TkDisplay *dispPtr = winPtr->dispPtr;

    /*
     * The selection is owned by some other process. To retrieve it, first
     * record information about the retrieval in progress. Use an internal
     * window as the requestor.
     */

    retr.interp = interp;
    if (dispPtr->clipWindow == NULL) {
	int result;

	result = TkClipInit(interp, dispPtr);
	if (result != TCL_OK) {
	    return result;
	}
    }
    retr.winPtr = (TkWindow *) dispPtr->clipWindow;
    retr.selection = selection;
    retr.property = selection;
    retr.target = target;
    retr.proc = proc;
    retr.clientData = clientData;
    retr.result = -1;
    retr.idleTime = 0;
    retr.encFlags = TCL_ENCODING_START;
    retr.nextPtr = pendingRetrievals;
    Tcl_DStringInit(&retr.buf);
    pendingRetrievals = &retr;

    /*
     * Delete the property to indicate that no parameters are supplied for
     * the conversion request.
     */

    XDeleteProperty(winPtr->display, retr.winPtr->window, retr.property);

    /*
     * Initiate the request for the selection. Note: can't use TkCurrentTime
     * for the time. If we do, and this application hasn't received any X
     * events in a long time, the current time will be way in the past and
     * could even predate the time when the selection was made; if this
     * happens, the request will be rejected.
     */

    XConvertSelection(winPtr->display, retr.selection, retr.target,
	    retr.property, retr.winPtr->window, CurrentTime);

    /*
     * Enter a loop processing X events until the selection has been retrieved
     * and processed. If no response is received within a few seconds, then
     * timeout.
     */

    retr.timeout = Tcl_CreateTimerHandler(1000, SelTimeoutProc,
	    &retr);
    while (retr.result == -1) {
	Tcl_DoOneEvent(0);
    }
    Tcl_DeleteTimerHandler(retr.timeout);

    /*
     * Unregister the information about the selection retrieval in progress.
     */

    if (pendingRetrievals == &retr) {
	pendingRetrievals = retr.nextPtr;
    } else {
	TkSelRetrievalInfo *retrPtr;

	for (retrPtr = pendingRetrievals; retrPtr != NULL;
		retrPtr = retrPtr->nextPtr) {
	    if (retrPtr->nextPtr == &retr) {
		retrPtr->nextPtr = retr.nextPtr;
		break;
	    }
	}
    }
    Tcl_DStringFree(&retr.buf);
    return retr.result;
}

/*
 *----------------------------------------------------------------------
 *
 * TkSelPropProc --
 *
 *	This function is invoked when property-change events occur on windows
 *	not known to the toolkit. Its function is to implement the sending
 *	side of the INCR selection retrieval protocol when the selection
 *	requestor deletes the property containing a part of the selection.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	If the property that is receiving the selection was just deleted, then
 *	a new piece of the selection is fetched and placed in the property,
 *	until eventually there's no more selection to fetch.
 *
 *----------------------------------------------------------------------
 */

void
TkSelPropProc(
    register XEvent *eventPtr)	/* X PropertyChange event. */
{
    register IncrInfo *incrPtr;
    register TkSelHandler *selPtr;
    int length, numItems;
    unsigned long i;
    Atom target, formatType;
    long buffer[TK_SEL_WORDS_AT_ONCE];
    TkDisplay *dispPtr = TkGetDisplay(eventPtr->xany.display);
    Tk_ErrorHandler errorHandler;
    ThreadSpecificData *tsdPtr =
	    Tcl_GetThreadData(&dataKey, sizeof(ThreadSpecificData));

    /*
     * See if this event announces the deletion of a property being used for
     * an INCR transfer. If so, then add the next chunk of data to the
     * property.
     */

    if (eventPtr->xproperty.state != PropertyDelete) {
	return;
    }
    for (incrPtr = tsdPtr->pendingIncrs; incrPtr != NULL;
	    incrPtr = incrPtr->nextPtr) {
	if (incrPtr->reqWindow != eventPtr->xproperty.window) {
	    continue;
	}

	/*
	 * For each conversion that has been requested, handle any chunks that
	 * haven't been transmitted yet.
	 */

	for (i = 0; i < incrPtr->numConversions; i++) {
	    if ((eventPtr->xproperty.atom != incrPtr->multAtoms[2*i + 1])
		    || (incrPtr->converts[i].offset == -1)) {
		continue;
	    }
	    target = incrPtr->multAtoms[2*i];
	    incrPtr->idleTime = 0;

	    /*
	     * Look for a matching selection handler.
	     */

	    for (selPtr = incrPtr->winPtr->selHandlerList; ;
		    selPtr = selPtr->nextPtr) {
		if (selPtr == NULL) {
		    /*
		     * No handlers match, so mark the conversion as done.
		     */

		    incrPtr->multAtoms[2*i + 1] = None;
		    incrPtr->converts[i].offset = -1;
		    incrPtr->numIncrs --;
		    return;
		}
		if ((selPtr->target == target)
			&& (selPtr->selection == incrPtr->selection)) {
		    break;
		}
	    }

	    /*
	     * We found a handler, so get the next chunk from it.
	     */

	    formatType = selPtr->format;
	    if (incrPtr->converts[i].offset == -2) {
		/*
		 * We already got the last chunk, so send a null chunk to
		 * indicate that we are finished.
		 */

		numItems = 0;
		length = 0;
	    } else {
		TkSelInProgress ip;

		ip.selPtr = selPtr;
		ip.nextPtr = TkSelGetInProgress();
		TkSelSetInProgress(&ip);

		/*
		 * Copy any bytes left over from a partial character at the
		 * end of the previous chunk into the beginning of the buffer.
		 * Pass the rest of the buffer space into the selection
		 * handler.
		 */

		length = strlen(incrPtr->converts[i].buffer);
		strcpy((char *)buffer, incrPtr->converts[i].buffer);

		numItems = selPtr->proc(selPtr->clientData,
			incrPtr->converts[i].offset,
			((char *) buffer) + length,
			TK_SEL_BYTES_AT_ONCE - length);
		TkSelSetInProgress(ip.nextPtr);
		if (ip.selPtr == NULL) {
		    /*
		     * The selection handler deleted itself.
		     */

		    return;
		}
		if (numItems < 0) {
		    numItems = 0;
		}
		numItems += length;
		if (numItems > TK_SEL_BYTES_AT_ONCE) {
		    Tcl_Panic("selection handler returned too many bytes");
		}
	    }
	    ((char *) buffer)[numItems] = 0;

	    errorHandler = Tk_CreateErrorHandler(eventPtr->xproperty.display,
		    -1, -1, -1, (int (*)()) NULL, NULL);

	    /*
	     * Encode the data using the proper format for each type.
	     */

	    if ((formatType == XA_STRING)
		    || (dispPtr && formatType==dispPtr->utf8Atom)
		    || (dispPtr && formatType==dispPtr->compoundTextAtom)) {
		Tcl_DString ds;
		int encodingCvtFlags;
		int srcLen, dstLen, result, srcRead, dstWrote, soFar;
		char *src, *dst;
		Tcl_Encoding encoding;

		/*
		 * Set up the encoding state based on the format and whether
		 * this is the first and/or last chunk.
		 */

		encodingCvtFlags = 0;
		if (incrPtr->converts[i].offset == 0) {
		    encodingCvtFlags |= TCL_ENCODING_START;
		}
		if (numItems < TK_SEL_BYTES_AT_ONCE) {
		    encodingCvtFlags |= TCL_ENCODING_END;
		}
		if (formatType == XA_STRING) {
		    encoding = Tcl_GetEncoding(NULL, "iso8859-1");
		} else if (dispPtr && formatType==dispPtr->utf8Atom) {
		    encoding = Tcl_GetEncoding(NULL, "utf-8");
		} else {
		    encoding = Tcl_GetEncoding(NULL, "iso2022");
		}

		/*
		 * Now convert the data.
		 */

		src = (char *)buffer;
		srcLen = numItems;
		Tcl_DStringInit(&ds);
		dst = Tcl_DStringValue(&ds);
		dstLen = ds.spaceAvl - 1;


		/*
		 * Now convert the data, growing the destination buffer as
		 * needed.
		 */

		while (1) {
		    result = Tcl_UtfToExternal(NULL, encoding, src, srcLen,
			    encodingCvtFlags, &incrPtr->converts[i].state,
			    dst, dstLen, &srcRead, &dstWrote, NULL);
		    soFar = dst + dstWrote - Tcl_DStringValue(&ds);
		    encodingCvtFlags &= ~TCL_ENCODING_START;
		    src += srcRead;
		    srcLen -= srcRead;
		    if (result != TCL_CONVERT_NOSPACE) {
			Tcl_DStringSetLength(&ds, soFar);
			break;
		    }
		    if (Tcl_DStringLength(&ds) == 0) {
			Tcl_DStringSetLength(&ds, dstLen);
		    }
		    Tcl_DStringSetLength(&ds, 2 * Tcl_DStringLength(&ds) + 1);
		    dst = Tcl_DStringValue(&ds) + soFar;
		    dstLen = Tcl_DStringLength(&ds) - soFar - 1;
		}
		Tcl_DStringSetLength(&ds, soFar);

		if (encoding) {
		    Tcl_FreeEncoding(encoding);
		}

		/*
		 * Set the property to the encoded string value.
		 */

		XChangeProperty(eventPtr->xproperty.display,
			eventPtr->xproperty.window, eventPtr->xproperty.atom,
			formatType, 8, PropModeReplace,
			(unsigned char *) Tcl_DStringValue(&ds),
			Tcl_DStringLength(&ds));

		/*
		 * Preserve any left-over bytes.
		 */

		if (srcLen > 4) {
		    Tcl_Panic("selection conversion left too many bytes unconverted");
		}
		memcpy(incrPtr->converts[i].buffer, src, (size_t) srcLen+1);
		Tcl_DStringFree(&ds);
	    } else {
		/*
		 * Set the property to the encoded string value.
		 */

		char *propPtr = (char *) SelCvtToX((char *) buffer,
			formatType, (Tk_Window) incrPtr->winPtr, &numItems);

		if (propPtr == NULL) {
		    numItems = 0;
		}
		XChangeProperty(eventPtr->xproperty.display,
			eventPtr->xproperty.window, eventPtr->xproperty.atom,
			formatType, 32, PropModeReplace,
			(unsigned char *) propPtr, numItems);
		if (propPtr != NULL) {
		    ckfree(propPtr);
		}
	    }
	    Tk_DeleteErrorHandler(errorHandler);

	    /*
	     * Compute the next offset value. If this was the last chunk, then
	     * set the offset to -2. If this was an empty chunk, then set the
	     * offset to -1 to indicate we are done.
	     */

	    if (numItems < TK_SEL_BYTES_AT_ONCE) {
		if (numItems <= 0) {
		    incrPtr->converts[i].offset = -1;
		    incrPtr->numIncrs--;
		} else {
		    incrPtr->converts[i].offset = -2;
		}
	    } else {
		/*
		 * Advance over the selection data that was consumed this
		 * time.
		 */

		incrPtr->converts[i].offset += numItems - length;
	    }
	    return;
	}
    }
}

/*
 *--------------------------------------------------------------
 *
 * TkSelEventProc --
 *
 *	This function is invoked whenever a selection-related event occurs.
 *	It does the lion's share of the work in implementing the selection
 *	protocol.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Lots: depends on the type of event.
 *
 *--------------------------------------------------------------
 */

void
TkSelEventProc(
    Tk_Window tkwin,		/* Window for which event was targeted. */
    register XEvent *eventPtr)	/* X event: either SelectionClear,
				 * SelectionRequest, or SelectionNotify. */
{
    register TkWindow *winPtr = (TkWindow *) tkwin;
    TkDisplay *dispPtr = winPtr->dispPtr;
    Tcl_Interp *interp;

    /*
     * Case #1: SelectionClear events.
     */

    if (eventPtr->type == SelectionClear) {
	TkSelClearSelection(tkwin, eventPtr);
    }

    /*
     * Case #2: SelectionNotify events. Call the relevant function to handle
     * the incoming selection.
     */

    if (eventPtr->type == SelectionNotify) {
	register TkSelRetrievalInfo *retrPtr;
	char *propInfo, **propInfoPtr = &propInfo;
	Atom type;
	int format, result;
	unsigned long numItems, bytesAfter;
	Tcl_DString ds;

	for (retrPtr = pendingRetrievals; ; retrPtr = retrPtr->nextPtr) {
	    if (retrPtr == NULL) {
		return;
	    }
	    if ((retrPtr->winPtr == winPtr)
		    && (retrPtr->selection == eventPtr->xselection.selection)
		    && (retrPtr->target == eventPtr->xselection.target)
		    && (retrPtr->result == -1)) {
		if (retrPtr->property == eventPtr->xselection.property) {
		    break;
		}
		if (eventPtr->xselection.property == None) {
		    Tcl_SetObjResult(retrPtr->interp, Tcl_ObjPrintf(
			    "%s selection doesn't exist or form \"%s\" not defined",
			    Tk_GetAtomName(tkwin, retrPtr->selection),
			    Tk_GetAtomName(tkwin, retrPtr->target)));
		    Tcl_SetErrorCode(retrPtr->interp, "TK", "SELECTION",
			    "NONE", NULL);
		    retrPtr->result = TCL_ERROR;
		    return;
		}
	    }
	}

	propInfo = NULL;
	result = XGetWindowProperty(eventPtr->xselection.display,
		eventPtr->xselection.requestor, retrPtr->property,
		0, MAX_PROP_WORDS, False, (Atom) AnyPropertyType,
		&type, &format, &numItems, &bytesAfter,
		(unsigned char **) propInfoPtr);
	if ((result != Success) || (type == None)) {
	    return;
	}
	if (bytesAfter != 0) {
	    Tcl_SetObjResult(retrPtr->interp, Tcl_NewStringObj(
		    "selection property too large", -1));
	    Tcl_SetErrorCode(retrPtr->interp, "TK", "SELECTION", "SIZE",NULL);
	    retrPtr->result = TCL_ERROR;
	    XFree(propInfo);
	    return;
	}
	if ((type == XA_STRING) || (type == dispPtr->textAtom)
		|| (type == dispPtr->compoundTextAtom)) {
	    Tcl_Encoding encoding;

	    if (format != 8) {
		Tcl_SetObjResult(retrPtr->interp, Tcl_ObjPrintf(
			"bad format for string selection: wanted \"8\", got \"%d\"",
			format));
		Tcl_SetErrorCode(retrPtr->interp, "TK", "SELECTION", "FORMAT",
			NULL);
		retrPtr->result = TCL_ERROR;
		return;
	    }
	    interp = retrPtr->interp;
	    Tcl_Preserve(interp);

	    /*
	     * Convert the X selection data into UTF before passing it to the
	     * selection callback. Note that the COMPOUND_TEXT uses a modified
	     * iso2022 encoding, not the current system encoding. For now
	     * we'll just blindly apply the iso2022 encoding. This is probably
	     * wrong, but it's a placeholder until we figure out what we're
	     * really supposed to do. For STRING, we need to use Latin-1
	     * instead. Again, it's not really the full iso8859-1 space, but
	     * this is close enough.
	     */

	    if (type == dispPtr->compoundTextAtom) {
		encoding = Tcl_GetEncoding(NULL, "iso2022");
	    } else {
		encoding = Tcl_GetEncoding(NULL, "iso8859-1");
	    }
	    Tcl_ExternalToUtfDString(encoding, propInfo, (int)numItems, &ds);
	    if (encoding) {
		Tcl_FreeEncoding(encoding);
	    }

	    retrPtr->result = retrPtr->proc(retrPtr->clientData, interp,
		    Tcl_DStringValue(&ds));
	    Tcl_DStringFree(&ds);
	    Tcl_Release(interp);
	} else if (type == dispPtr->utf8Atom) {
	    /*
	     * The X selection data is in UTF-8 format already. We can't
	     * guarantee that propInfo is NULL-terminated, so we might have to
	     * copy the string.
	     */

	    char *propData = propInfo;

	    if (format != 8) {
		Tcl_SetObjResult(retrPtr->interp, Tcl_ObjPrintf(
			"bad format for string selection: wanted \"8\", got \"%d\"",
			format));
		Tcl_SetErrorCode(retrPtr->interp, "TK", "SELECTION", "FORMAT",
			NULL);
		retrPtr->result = TCL_ERROR;
		return;
	    }

	    if (propInfo[numItems] != '\0') {
		propData = ckalloc(numItems + 1);
		strcpy(propData, propInfo);
		propData[numItems] = '\0';
	    }
	    retrPtr->result = retrPtr->proc(retrPtr->clientData,
		    retrPtr->interp, propData);
	    if (propData != propInfo) {
		ckfree(propData);
	    }

	} else if (type == dispPtr->incrAtom) {
	    /*
	     * It's a !?#@!?!! INCR-style reception. Arrange to receive the
	     * selection in pieces, using the ICCCM protocol, then hang around
	     * until either the selection is all here or a timeout occurs.
	     */

	    retrPtr->idleTime = 0;
	    Tk_CreateEventHandler(tkwin, PropertyChangeMask, SelRcvIncrProc,
		    retrPtr);
	    XDeleteProperty(Tk_Display(tkwin), Tk_WindowId(tkwin),
		    retrPtr->property);
	    while (retrPtr->result == -1) {
		Tcl_DoOneEvent(0);
	    }
	    Tk_DeleteEventHandler(tkwin, PropertyChangeMask, SelRcvIncrProc,
		    retrPtr);
	} else {
	    Tcl_DString ds;

	    if (format != 32 && format != 8) {
		Tcl_SetObjResult(retrPtr->interp, Tcl_ObjPrintf(
			"bad format for selection: wanted \"32\" or "
			"\"8\", got \"%d\"", format));
		Tcl_SetErrorCode(retrPtr->interp, "TK", "SELECTION", "FORMAT",
			NULL);
		retrPtr->result = TCL_ERROR;
		return;
	    }
	    Tcl_DStringInit(&ds);
	    if (format == 32) {
		SelCvtFromX32((long *) propInfo, (int) numItems, type,
			(Tk_Window) winPtr, &ds);
	    } else {
		SelCvtFromX8((char *) propInfo, (int) numItems, type,
			(Tk_Window) winPtr, &ds);
	    }
	    interp = retrPtr->interp;
	    Tcl_Preserve(interp);
	    retrPtr->result = retrPtr->proc(retrPtr->clientData,
		    interp, Tcl_DStringValue(&ds));
	    Tcl_Release(interp);
	    Tcl_DStringFree(&ds);
	}
	XFree(propInfo);
	return;
    }

    /*
     * Case #3: SelectionRequest events. Call ConvertSelection to do the dirty
     * work.
     */

    if (eventPtr->type == SelectionRequest) {
	ConvertSelection(winPtr, &eventPtr->xselectionrequest);
	return;
    }
}

/*
 *----------------------------------------------------------------------
 *
 * SelTimeoutProc --
 *
 *	This function is invoked once every second while waiting for the
 *	selection to be returned. After a while it gives up and aborts the
 *	selection retrieval.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	A new timer callback is created to call us again in another second,
 *	unless time has expired, in which case an error is recorded for the
 *	retrieval.
 *
 *----------------------------------------------------------------------
 */

static void
SelTimeoutProc(
    ClientData clientData)	/* Information about retrieval in progress. */
{
    register TkSelRetrievalInfo *retrPtr = clientData;

    /*
     * Make sure that the retrieval is still in progress. Then see how long
     * it's been since any sort of response was received from the other side.
     */

    if (retrPtr->result != -1) {
	return;
    }
    retrPtr->idleTime++;
    if (retrPtr->idleTime >= 5) {
	/*
	 * Use a careful function to store the error message, because the
	 * result could already be partially filled in with a partial
	 * selection return.
	 */

	Tcl_SetObjResult(retrPtr->interp, Tcl_NewStringObj(
		"selection owner didn't respond", -1));
	Tcl_SetErrorCode(retrPtr->interp, "TK", "SELECTION", "IGNORED", NULL);
	retrPtr->result = TCL_ERROR;
    } else {
	retrPtr->timeout = Tcl_CreateTimerHandler(1000, SelTimeoutProc,
		(ClientData) retrPtr);
    }
}

/*
 *----------------------------------------------------------------------
 *
 * ConvertSelection --
 *
 *	This function is invoked to handle SelectionRequest events. It
 *	responds to the requests, obeying the ICCCM protocols.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	Properties are created for the selection requestor, and a
 *	SelectionNotify event is generated for the selection requestor. In the
 *	event of long selections, this function implements INCR-mode
 *	transfers, using the ICCCM protocol.
 *
 *----------------------------------------------------------------------
 */

static void
ConvertSelection(
    TkWindow *winPtr,		/* Window that received the conversion
				 * request; may not be selection's current
				 * owner, be we set it to the current
				 * owner. */
    register XSelectionRequestEvent *eventPtr)
				/* Event describing request. */
{
	union {
		XSelectionEvent xsel;
		XEvent ev;
	} reply;	/* Used to notify requestor that selection
				 * info is ready. */
    int multiple;		/* Non-zero means a MULTIPLE request is being
				 * handled. */
    IncrInfo incr;		/* State of selection conversion. */
    Atom singleInfo[2];		/* incr.multAtoms points here except for
				 * multiple conversions. */
    unsigned long i;
    Tk_ErrorHandler errorHandler;
    TkSelectionInfo *infoPtr;
    TkSelInProgress ip;
    ThreadSpecificData *tsdPtr =
	    Tcl_GetThreadData(&dataKey, sizeof(ThreadSpecificData));

    errorHandler = Tk_CreateErrorHandler(eventPtr->display, -1, -1,-1,
	    (int (*)()) NULL, NULL);

    /*
     * Initialize the reply event.
     */

    reply.xsel.type = SelectionNotify;
    reply.xsel.serial = 0;
    reply.xsel.send_event = True;
    reply.xsel.display = eventPtr->display;
    reply.xsel.requestor = eventPtr->requestor;
    reply.xsel.selection = eventPtr->selection;
    reply.xsel.target = eventPtr->target;
    reply.xsel.property = eventPtr->property;
    if (reply.xsel.property == None) {
	reply.xsel.property = reply.xsel.target;
    }
    reply.xsel.time = eventPtr->time;

    for (infoPtr = winPtr->dispPtr->selectionInfoPtr; infoPtr != NULL;
	    infoPtr = infoPtr->nextPtr) {
	if (infoPtr->selection == eventPtr->selection) {
	    break;
	}
    }
    if (infoPtr == NULL) {
	goto refuse;
    }
    winPtr = (TkWindow *) infoPtr->owner;

    /*
     * Figure out which kind(s) of conversion to perform. If handling a
     * MULTIPLE conversion, then read the property describing which
     * conversions to perform.
     */

    incr.winPtr = winPtr;
    incr.selection = eventPtr->selection;
    if (eventPtr->target != winPtr->dispPtr->multipleAtom) {
	multiple = 0;
	singleInfo[0] = reply.xsel.target;
	singleInfo[1] = reply.xsel.property;
	incr.multAtoms = singleInfo;
	incr.numConversions = 1;
    } else {
	Atom type, **multAtomsPtr = &incr.multAtoms;
	int format, result;
	unsigned long bytesAfter;

	multiple = 1;
	incr.multAtoms = NULL;
	if (eventPtr->property == None) {
	    goto refuse;
	}
	result = XGetWindowProperty(eventPtr->display, eventPtr->requestor,
		eventPtr->property, 0, MAX_PROP_WORDS, False, XA_ATOM,
		&type, &format, &incr.numConversions, &bytesAfter,
		(unsigned char **) multAtomsPtr);
	if ((result != Success) || (bytesAfter != 0) || (format != 32)
		|| (type == None)) {
	    if (incr.multAtoms != NULL) {
		XFree((char *) incr.multAtoms);
	    }
	    goto refuse;
	}
	incr.numConversions /= 2;	/* Two atoms per conversion. */
    }

    /*
     * Loop through all of the requested conversions, and either return the
     * entire converted selection, if it can be returned in a single bunch, or
     * return INCR information only (the actual selection will be returned
     * below).
     */

    incr.converts = ckalloc(incr.numConversions * sizeof(ConvertInfo));
    incr.numIncrs = 0;
    for (i = 0; i < incr.numConversions; i++) {
	Atom target, property, type;
	long buffer[TK_SEL_WORDS_AT_ONCE];
	register TkSelHandler *selPtr;
	int numItems, format;
	char *propPtr;

	target = incr.multAtoms[2*i];
	property = incr.multAtoms[2*i + 1];
	incr.converts[i].offset = -1;
	incr.converts[i].buffer[0] = '\0';

	for (selPtr = winPtr->selHandlerList; selPtr != NULL;
		selPtr = selPtr->nextPtr) {
	    if ((selPtr->target == target)
		    && (selPtr->selection == eventPtr->selection)) {
		break;
	    }
	}

	if (selPtr == NULL) {
	    /*
	     * Nobody seems to know about this kind of request. If it's of a
	     * sort that we can handle without any help, do it. Otherwise mark
	     * the request as an errror.
	     */

	    numItems = TkSelDefaultSelection(infoPtr, target, (char *) buffer,
		    TK_SEL_BYTES_AT_ONCE, &type);
	    if (numItems < 0) {
		incr.multAtoms[2*i + 1] = None;
		continue;
	    }
	} else {
	    ip.selPtr = selPtr;
	    ip.nextPtr = TkSelGetInProgress();
	    TkSelSetInProgress(&ip);
	    type = selPtr->format;
	    numItems = selPtr->proc(selPtr->clientData, 0, (char *) buffer,
		    TK_SEL_BYTES_AT_ONCE);
	    TkSelSetInProgress(ip.nextPtr);
	    if ((ip.selPtr == NULL) || (numItems < 0)) {
		incr.multAtoms[2*i + 1] = None;
		continue;
	    }
	    if (numItems > TK_SEL_BYTES_AT_ONCE) {
		Tcl_Panic("selection handler returned too many bytes");
	    }
	    ((char *) buffer)[numItems] = '\0';
	}

	/*
	 * Got the selection; store it back on the requestor's property.
	 */

	if (numItems == TK_SEL_BYTES_AT_ONCE) {
	    /*
	     * Selection is too big to send at once; start an INCR-mode
	     * transfer.
	     */

	    incr.numIncrs++;
	    type = winPtr->dispPtr->incrAtom;
	    buffer[0] = SelectionSize(selPtr);
	    if (buffer[0] == 0) {
		incr.multAtoms[2*i + 1] = None;
		continue;
	    }
	    numItems = 1;
	    propPtr = (char *) buffer;
	    format = 32;
	    incr.converts[i].offset = 0;
	    XChangeProperty(reply.xsel.display, reply.xsel.requestor,
		    property, type, format, PropModeReplace,
		    (unsigned char *) propPtr, numItems);
	} else if (type == winPtr->dispPtr->utf8Atom) {
	    /*
	     * This matches selection requests of type UTF8_STRING, which
	     * allows us to pass our utf-8 information untouched.
	     */

	    XChangeProperty(reply.xsel.display, reply.xsel.requestor,
		    property, type, 8, PropModeReplace,
		    (unsigned char *) buffer, numItems);
	} else if ((type == XA_STRING)
		|| (type == winPtr->dispPtr->compoundTextAtom)) {
	    Tcl_DString ds;
	    Tcl_Encoding encoding;

	    /*
	     * STRING is Latin-1, COMPOUND_TEXT is an iso2022 variant. We need
	     * to convert the selection text into these external forms before
	     * modifying the property.
	     */

	    if (type == XA_STRING) {
		encoding = Tcl_GetEncoding(NULL, "iso8859-1");
	    } else {
		encoding = Tcl_GetEncoding(NULL, "iso2022");
	    }
	    Tcl_UtfToExternalDString(encoding, (char *) buffer, -1, &ds);
	    XChangeProperty(reply.xsel.display, reply.xsel.requestor,
		    property, type, 8, PropModeReplace,
		    (unsigned char *) Tcl_DStringValue(&ds),
		    Tcl_DStringLength(&ds));
	    if (encoding) {
		Tcl_FreeEncoding(encoding);
	    }
	    Tcl_DStringFree(&ds);
	} else {
	    propPtr = (char *) SelCvtToX((char *) buffer,
		    type, (Tk_Window) winPtr, &numItems);
	    if (propPtr == NULL) {
		goto refuse;
	    }
	    format = 32;
	    XChangeProperty(reply.xsel.display, reply.xsel.requestor,
		    property, type, format, PropModeReplace,
		    (unsigned char *) propPtr, numItems);
	    ckfree(propPtr);
	}
    }

    /*
     * Send an event back to the requestor to indicate that the first stage of
     * conversion is complete (everything is done except for long conversions
     * that have to be done in INCR mode).
     */

    if (incr.numIncrs > 0) {
	XSelectInput(reply.xsel.display, reply.xsel.requestor,
		PropertyChangeMask);
	incr.timeout = Tcl_CreateTimerHandler(1000, IncrTimeoutProc, &incr);
	incr.idleTime = 0;
	incr.reqWindow = reply.xsel.requestor;
	incr.time = infoPtr->time;
	incr.nextPtr = tsdPtr->pendingIncrs;
	tsdPtr->pendingIncrs = &incr;
    }
    if (multiple) {
	XChangeProperty(reply.xsel.display, reply.xsel.requestor,
		reply.xsel.property, XA_ATOM, 32, PropModeReplace,
		(unsigned char *) incr.multAtoms,
		(int) incr.numConversions*2);
    } else {
	/*
	 * Not a MULTIPLE request. The first property in "multAtoms" got set
	 * to None if there was an error in conversion.
	 */

	reply.xsel.property = incr.multAtoms[1];
    }
    XSendEvent(reply.xsel.display, reply.xsel.requestor, False, 0, &reply.ev);
    Tk_DeleteErrorHandler(errorHandler);

    /*
     * Handle any remaining INCR-mode transfers. This all happens in callbacks
     * to TkSelPropProc, so just wait until the number of uncompleted INCR
     * transfers drops to zero.
     */

    if (incr.numIncrs > 0) {
	IncrInfo *incrPtr2;

	while (incr.numIncrs > 0) {
	    Tcl_DoOneEvent(0);
	}
	Tcl_DeleteTimerHandler(incr.timeout);
	errorHandler = Tk_CreateErrorHandler(winPtr->display,
		-1, -1, -1, (int (*)()) NULL, NULL);
	XSelectInput(reply.xsel.display, reply.xsel.requestor, 0L);
	Tk_DeleteErrorHandler(errorHandler);
	if (tsdPtr->pendingIncrs == &incr) {
	    tsdPtr->pendingIncrs = incr.nextPtr;
	} else {
	    for (incrPtr2 = tsdPtr->pendingIncrs; incrPtr2 != NULL;
		    incrPtr2 = incrPtr2->nextPtr) {
		if (incrPtr2->nextPtr == &incr) {
		    incrPtr2->nextPtr = incr.nextPtr;
		    break;
		}
	    }
	}
    }

    /*
     * All done. Cleanup and return.
     */

    ckfree(incr.converts);
    if (multiple) {
	XFree((char *) incr.multAtoms);
    }
    return;

    /*
     * An error occurred. Send back a refusal message.
     */

  refuse:
    reply.xsel.property = None;
    XSendEvent(reply.xsel.display, reply.xsel.requestor, False, 0, &reply.ev);
    Tk_DeleteErrorHandler(errorHandler);
    return;
}

/*
 *----------------------------------------------------------------------
 *
 * SelRcvIncrProc --
 *
 *	This function handles the INCR protocol on the receiving side. It is
 *	invoked in response to property changes on the requestor's window
 *	(which hopefully are because a new chunk of the selection arrived).
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	If a new piece of selection has arrived, a function is invoked to deal
 *	with that piece. When the whole selection is here, a flag is left for
 *	the higher-level function that initiated the selection retrieval.
 *
 *----------------------------------------------------------------------
 */

static void
SelRcvIncrProc(
    ClientData clientData,	/* Information about retrieval. */
    register XEvent *eventPtr)	/* X PropertyChange event. */
{
    register TkSelRetrievalInfo *retrPtr = clientData;
    char *propInfo, **propInfoPtr = &propInfo;
    Atom type;
    int format, result;
    unsigned long numItems, bytesAfter;
    Tcl_Interp *interp;

    if ((eventPtr->xproperty.atom != retrPtr->property)
	    || (eventPtr->xproperty.state != PropertyNewValue)
	    || (retrPtr->result != -1)) {
	return;
    }
    propInfo = NULL;
    result = XGetWindowProperty(eventPtr->xproperty.display,
	    eventPtr->xproperty.window, retrPtr->property, 0, MAX_PROP_WORDS,
	    True, (Atom) AnyPropertyType, &type, &format, &numItems,
	    &bytesAfter, (unsigned char **) propInfoPtr);
    if ((result != Success) || (type == None)) {
	return;
    }
    if (bytesAfter != 0) {
	Tcl_SetObjResult(retrPtr->interp, Tcl_NewStringObj(
		"selection property too large", -1));
	Tcl_SetErrorCode(retrPtr->interp, "TK", "SELECTION", "SIZE", NULL);
	retrPtr->result = TCL_ERROR;
	goto done;
    }
    if ((type == XA_STRING)
	    || (type == retrPtr->winPtr->dispPtr->textAtom)
	    || (type == retrPtr->winPtr->dispPtr->utf8Atom)
	    || (type == retrPtr->winPtr->dispPtr->compoundTextAtom)) {
	char *dst, *src;
	int srcLen, dstLen, srcRead, dstWrote, soFar;
	Tcl_Encoding encoding;
	Tcl_DString *dstPtr, temp;

	if (format != 8) {
	    Tcl_SetObjResult(retrPtr->interp, Tcl_ObjPrintf(
		    "bad format for string selection: wanted \"8\", got \"%d\"",
		    format));
	    Tcl_SetErrorCode(retrPtr->interp, "TK", "SELECTION", "FORMAT",
		    NULL);
	    retrPtr->result = TCL_ERROR;
	    goto done;
	}
	interp = retrPtr->interp;
	Tcl_Preserve(interp);

	if (type == retrPtr->winPtr->dispPtr->compoundTextAtom) {
	    encoding = Tcl_GetEncoding(NULL, "iso2022");
	} else if (type == retrPtr->winPtr->dispPtr->utf8Atom) {
	    encoding = Tcl_GetEncoding(NULL, "utf-8");
	} else {
	    encoding = Tcl_GetEncoding(NULL, "iso8859-1");
	}

	/*
	 * Check to see if there is any data left over from the previous
	 * chunk. If there is, copy the old data and the new data into a new
	 * buffer.
	 */

	Tcl_DStringInit(&temp);
	if (Tcl_DStringLength(&retrPtr->buf) > 0) {
	    Tcl_DStringAppend(&temp, Tcl_DStringValue(&retrPtr->buf),
		    Tcl_DStringLength(&retrPtr->buf));
	    if (numItems > 0) {
		Tcl_DStringAppend(&temp, propInfo, (int)numItems);
	    }
	    src = Tcl_DStringValue(&temp);
	    srcLen = Tcl_DStringLength(&temp);
	} else if (numItems == 0) {
	    /*
	     * There is no new data, so we're done.
	     */

	    retrPtr->result = TCL_OK;
	    Tcl_Release(interp);
	    goto done;
	} else {
	    src = propInfo;
	    srcLen = numItems;
	}

	/*
	 * Set up the destination buffer so we can use as much space as is
	 * available.
	 */

	dstPtr = &retrPtr->buf;
	dst = Tcl_DStringValue(dstPtr);
	dstLen = dstPtr->spaceAvl - 1;

	/*
	 * Now convert the data, growing the destination buffer as needed.
	 */

	while (1) {
	    result = Tcl_ExternalToUtf(NULL, encoding, src, srcLen,
		    retrPtr->encFlags, &retrPtr->encState,
		    dst, dstLen, &srcRead, &dstWrote, NULL);
	    soFar = dst + dstWrote - Tcl_DStringValue(dstPtr);
	    retrPtr->encFlags &= ~TCL_ENCODING_START;
	    src += srcRead;
	    srcLen -= srcRead;
	    if (result != TCL_CONVERT_NOSPACE) {
		Tcl_DStringSetLength(dstPtr, soFar);
		break;
	    }
	    if (Tcl_DStringLength(dstPtr) == 0) {
		Tcl_DStringSetLength(dstPtr, dstLen);
	    }
	    Tcl_DStringSetLength(dstPtr, 2 * Tcl_DStringLength(dstPtr) + 1);
	    dst = Tcl_DStringValue(dstPtr) + soFar;
	    dstLen = Tcl_DStringLength(dstPtr) - soFar - 1;
	}
	Tcl_DStringSetLength(dstPtr, soFar);

	result = retrPtr->proc(retrPtr->clientData, interp,
		Tcl_DStringValue(dstPtr));
	Tcl_Release(interp);

	/*
	 * Copy any unused data into the destination buffer so we can pick it
	 * up next time around.
	 */

	Tcl_DStringSetLength(dstPtr, 0);
	Tcl_DStringAppend(dstPtr, src, srcLen);

	Tcl_DStringFree(&temp);
	if (encoding) {
	    Tcl_FreeEncoding(encoding);
	}
	if (result != TCL_OK) {
	    retrPtr->result = result;
	}
    } else if (numItems == 0) {
	retrPtr->result = TCL_OK;
    } else {
	Tcl_DString ds;

	if (format != 32 && format != 8) {
	    Tcl_SetObjResult(retrPtr->interp, Tcl_ObjPrintf(
		    "bad format for selection: wanted \"32\" or "
		    "\"8\", got \"%d\"", format));
	    Tcl_SetErrorCode(retrPtr->interp, "TK", "SELECTION", "FORMAT",
		    NULL);
	    retrPtr->result = TCL_ERROR;
	    goto done;
	}
	Tcl_DStringInit(&ds);
	if (format == 32) {
	    SelCvtFromX32((long *) propInfo, (int) numItems, type,
		    (Tk_Window) retrPtr->winPtr, &ds);
	} else {
	    SelCvtFromX8((char *) propInfo, (int) numItems, type,
		    (Tk_Window) retrPtr->winPtr, &ds);
	}
	interp = retrPtr->interp;
	Tcl_Preserve(interp);
	result = retrPtr->proc(retrPtr->clientData, interp,
		Tcl_DStringValue(&ds));
	Tcl_Release(interp);
	Tcl_DStringFree(&ds);
	if (result != TCL_OK) {
	    retrPtr->result = result;
	}
    }

  done:
    XFree(propInfo);
    retrPtr->idleTime = 0;
}

/*
 *----------------------------------------------------------------------
 *
 * SelectionSize --
 *
 *	This function is called when the selection is too large to send in a
 *	single buffer; it computes the total length of the selection in bytes.
 *
 * Results:
 *	The return value is the number of bytes in the selection given by
 *	selPtr.
 *
 * Side effects:
 *	The selection is retrieved from its current owner (this is the only
 *	way to compute its size).
 *
 *----------------------------------------------------------------------
 */

static int
SelectionSize(
    TkSelHandler *selPtr)	/* Information about how to retrieve the
				 * selection whose size is wanted. */
{
    char buffer[TK_SEL_BYTES_AT_ONCE+1];
    int size, chunkSize;
    TkSelInProgress ip;

    size = TK_SEL_BYTES_AT_ONCE;
    ip.selPtr = selPtr;
    ip.nextPtr = TkSelGetInProgress();
    TkSelSetInProgress(&ip);

    do {
	chunkSize = selPtr->proc(selPtr->clientData, size, (char *) buffer,
		TK_SEL_BYTES_AT_ONCE);
	if (ip.selPtr == NULL) {
	    size = 0;
	    break;
	}
	size += chunkSize;
    } while (chunkSize == TK_SEL_BYTES_AT_ONCE);

    TkSelSetInProgress(ip.nextPtr);
    return size;
}

/*
 *----------------------------------------------------------------------
 *
 * IncrTimeoutProc --
 *
 *	This function is invoked once a second while sending the selection to
 *	a requestor in INCR mode. After a while it gives up and aborts the
 *	selection operation.
 *
 * Results:
 *	None.
 *
 * Side effects:
 *	A new timeout gets registered so that this function gets called again
 *	in another second, unless too many seconds have elapsed, in which case
 *	incrPtr is marked as "all done".
 *
 *----------------------------------------------------------------------
 */

static void
IncrTimeoutProc(
    ClientData clientData)	/* Information about INCR-mode selection
				 * retrieval for which we are selection
				 * owner. */
{
    register IncrInfo *incrPtr = clientData;

    incrPtr->idleTime++;
    if (incrPtr->idleTime >= 5) {
	incrPtr->numIncrs = 0;
    } else {
	incrPtr->timeout = Tcl_CreateTimerHandler(1000, IncrTimeoutProc,
		incrPtr);
    }
}

/*
 *----------------------------------------------------------------------
 *
 * SelCvtToX --
 *
 *	Given a selection represented as a string (the normal Tcl form),
 *	convert it to the ICCCM-mandated format for X, depending on the type
 *	argument. This function and SelCvtFromX are inverses.
 *
 * Results:
 *	The return value is a malloc'ed buffer holding a value equivalent to
 *	"string", but formatted as for "type". It is the caller's
 *	responsibility to free the string when done with it. The word at
 *	*numLongsPtr is filled in with the number of 32-bit words returned in
 *	the result. If NULL is returned, the input list was not actually a
 *	list.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

static long *
SelCvtToX(
    char *string,		/* String representation of selection. */
    Atom type,			/* Atom specifying the X format that is
				 * desired for the selection. Should not be
				 * XA_STRING (if so, don't bother calling this
				 * function at all). */
    Tk_Window tkwin,		/* Window that governs atom conversion. */
    int *numLongsPtr)		/* Number of 32-bit words contained in the
				 * result. */
{
    const char **field;
    int numFields, i;
    long *propPtr;

    /*
     * The string is assumed to consist of fields separated by spaces. The
     * property gets generated by converting each field to an integer number,
     * in one of two ways:
     * 1. If type is XA_ATOM, convert each field to its corresponding atom.
     * 2. If type is anything else, convert each field from an ASCII number to
     *    a 32-bit binary number.
     */

    if (Tcl_SplitList(NULL, string, &numFields, &field) != TCL_OK) {
	return NULL;
    }
    propPtr = ckalloc(numFields * sizeof(long));

    /*
     * Convert the fields one-by-one.
     */

    for (i=0 ; i<numFields ; i++) {
	if (type == XA_ATOM) {
	    propPtr[i] = (long) Tk_InternAtom(tkwin, field[i]);
	} else {
	    char *dummy;

	    /*
	     * If this fails to parse a number, we just plunge on regardless
	     * anyway.
	     */

	    propPtr[i] = strtol(field[i], &dummy, 0);
	}
    }

    /*
     * Release the parsed list.
     */

    ckfree(field);
    *numLongsPtr = i;
    return propPtr;
}

/*
 *----------------------------------------------------------------------
 *
 * SelCvtFromX32, SelCvtFromX8 --
 *
 *	Given an X property value, formatted as a collection of 32-bit or
 *	8-bit values according to "type" and the ICCCM conventions, convert
 *	the value to a string suitable for manipulation by Tcl. These
 *	functions are the inverse of SelCvtToX.
 *
 * Results:
 *	The return value (stored in a Tcl_DString) is the string equivalent of
 *	"property". It is up to the caller to initialize and free the DString.
 *
 * Side effects:
 *	None.
 *
 *----------------------------------------------------------------------
 */

static void
SelCvtFromX32(
    register long *propPtr,	/* Property value from X. */
    int numValues,		/* Number of 32-bit values in property. */
    Atom type,			/* Type of property Should not be XA_STRING
				 * (if so, don't bother calling this function
				 * at all). */
    Tk_Window tkwin,		/* Window to use for atom conversion. */
    Tcl_DString *dsPtr)		/* Where to store the converted string. */
{
    /*
     * Convert each long in the property to a string value, which is either
     * the name of an atom (if type is XA_ATOM) or a hexadecimal string. We
     * build the list in a Tcl_DString because this is easier than trying to
     * get the quoting correct ourselves; this is tricky because atoms can
     * contain spaces in their names (encountered when the atoms are really
     * MIME types). [Bug 1353414]
     */

    for ( ; numValues > 0; propPtr++, numValues--) {
	if (type == XA_ATOM) {
	    Tcl_DStringAppendElement(dsPtr,
		    Tk_GetAtomName(tkwin, (Atom) *propPtr));
	} else {
	    char buf[12];

	    sprintf(buf, "0x%x", (unsigned int) *propPtr);
	    Tcl_DStringAppendElement(dsPtr, buf);
	}
    }
    Tcl_DStringAppend(dsPtr, " ", 1);
}

static void
SelCvtFromX8(
    register char *propPtr,	/* Property value from X. */
    int numValues,		/* Number of 8-bit values in property. */
    Atom type,			/* Type of property Should not be XA_STRING
				 * (if so, don't bother calling this function
				 * at all). */
    Tk_Window tkwin,		/* Window to use for atom conversion. */
    Tcl_DString *dsPtr)		/* Where to store the converted string. */
{
    /*
     * Convert each long in the property to a string value, which is a
     * hexadecimal string. We build the list in a Tcl_DString because this is
     * easier than trying to get the quoting correct ourselves.
     */

    for ( ; numValues > 0; propPtr++, numValues--) {
	char buf[12];

	sprintf(buf, "0x%x", (unsigned char) *propPtr);
	Tcl_DStringAppendElement(dsPtr, buf);
    }
    Tcl_DStringAppend(dsPtr, " ", 1);
}

/*
 * Local Variables:
 * mode: c
 * c-basic-offset: 4
 * fill-column: 78
 * End:
 */