summaryrefslogtreecommitdiff
path: root/luaotfload-database.lua
blob: 8268283cbf022e4ecfc3132c80282b4588500224 (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
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
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
2271
2272
2273
2274
2275
2276
2277
2278
2279
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
2292
2293
2294
2295
2296
2297
2298
2299
2300
2301
2302
2303
2304
2305
2306
2307
2308
2309
2310
2311
2312
2313
2314
2315
2316
2317
2318
2319
2320
2321
2322
2323
2324
2325
2326
2327
2328
2329
2330
2331
2332
2333
2334
2335
2336
2337
2338
2339
2340
2341
2342
2343
2344
2345
2346
2347
2348
2349
2350
2351
2352
2353
2354
2355
2356
2357
2358
2359
2360
2361
2362
2363
2364
2365
2366
2367
2368
2369
2370
2371
2372
2373
2374
2375
2376
2377
2378
2379
2380
2381
2382
2383
2384
2385
2386
2387
2388
2389
2390
2391
2392
2393
2394
2395
2396
2397
2398
2399
2400
2401
2402
2403
2404
2405
2406
2407
2408
2409
2410
2411
2412
2413
2414
2415
2416
2417
2418
2419
2420
2421
2422
2423
2424
2425
2426
2427
2428
2429
2430
2431
2432
2433
2434
2435
2436
2437
2438
2439
2440
2441
2442
2443
2444
2445
2446
2447
2448
2449
2450
2451
2452
2453
2454
2455
2456
2457
2458
2459
2460
2461
2462
2463
2464
2465
2466
2467
2468
2469
2470
2471
2472
2473
2474
2475
2476
2477
2478
2479
2480
2481
2482
2483
2484
2485
2486
2487
2488
2489
2490
2491
2492
2493
2494
2495
2496
2497
2498
2499
2500
2501
2502
2503
2504
2505
2506
2507
2508
2509
2510
2511
2512
2513
2514
2515
2516
2517
2518
2519
2520
2521
2522
2523
2524
2525
2526
2527
2528
2529
2530
2531
2532
2533
2534
2535
2536
2537
2538
2539
2540
2541
2542
2543
2544
2545
2546
2547
2548
2549
2550
2551
2552
2553
2554
2555
2556
2557
2558
2559
2560
2561
2562
2563
2564
2565
2566
2567
2568
2569
2570
2571
2572
2573
2574
2575
2576
2577
2578
2579
2580
2581
2582
2583
2584
2585
2586
2587
2588
2589
2590
2591
2592
2593
2594
2595
2596
2597
2598
2599
2600
2601
2602
2603
2604
2605
2606
2607
2608
2609
2610
2611
2612
2613
2614
2615
2616
2617
2618
2619
2620
2621
2622
2623
2624
2625
2626
2627
2628
2629
2630
2631
2632
2633
2634
2635
2636
2637
2638
2639
2640
2641
2642
2643
2644
2645
2646
2647
2648
2649
2650
2651
2652
2653
2654
2655
2656
2657
2658
2659
2660
2661
2662
2663
2664
2665
2666
2667
2668
2669
2670
2671
2672
2673
2674
2675
2676
2677
2678
2679
2680
2681
2682
2683
2684
2685
2686
2687
2688
2689
2690
2691
2692
2693
2694
2695
2696
2697
2698
2699
2700
2701
2702
2703
2704
2705
2706
2707
2708
2709
2710
2711
2712
2713
2714
2715
2716
2717
2718
2719
2720
2721
2722
2723
2724
2725
2726
2727
2728
2729
2730
2731
2732
2733
2734
2735
2736
2737
2738
2739
2740
2741
2742
2743
2744
2745
2746
2747
2748
2749
2750
2751
2752
2753
2754
2755
2756
2757
2758
2759
2760
2761
2762
2763
2764
2765
2766
2767
2768
2769
2770
2771
2772
2773
2774
2775
2776
2777
2778
2779
2780
2781
2782
2783
2784
2785
2786
2787
2788
2789
2790
2791
2792
2793
2794
2795
2796
2797
2798
2799
2800
2801
2802
2803
2804
2805
2806
2807
2808
2809
2810
2811
2812
2813
2814
2815
2816
2817
2818
2819
2820
2821
2822
2823
2824
2825
2826
2827
2828
2829
2830
2831
2832
2833
2834
2835
2836
2837
2838
2839
2840
2841
2842
2843
2844
2845
2846
2847
2848
2849
2850
2851
2852
2853
2854
2855
2856
2857
2858
2859
2860
2861
2862
2863
2864
2865
2866
2867
2868
2869
2870
2871
2872
2873
2874
2875
2876
2877
2878
2879
2880
2881
2882
2883
2884
2885
2886
2887
2888
2889
2890
2891
2892
2893
2894
2895
2896
2897
2898
2899
2900
2901
2902
2903
2904
2905
2906
2907
2908
2909
2910
2911
2912
2913
2914
2915
2916
2917
2918
2919
2920
2921
2922
2923
2924
2925
2926
2927
2928
2929
2930
2931
2932
2933
2934
2935
2936
2937
2938
2939
2940
2941
2942
2943
2944
2945
2946
2947
2948
2949
2950
2951
2952
2953
2954
2955
2956
2957
2958
2959
2960
2961
2962
2963
2964
2965
2966
2967
2968
2969
2970
2971
2972
2973
2974
2975
2976
2977
2978
2979
2980
2981
2982
2983
2984
2985
2986
2987
2988
2989
2990
2991
2992
2993
2994
2995
2996
2997
2998
2999
3000
3001
3002
3003
3004
3005
3006
3007
3008
3009
3010
3011
3012
3013
3014
3015
3016
3017
3018
3019
3020
3021
3022
3023
3024
3025
3026
3027
3028
3029
3030
3031
3032
3033
3034
3035
3036
3037
3038
3039
3040
3041
3042
3043
3044
3045
3046
3047
3048
3049
3050
3051
3052
3053
3054
3055
3056
3057
3058
3059
3060
3061
3062
3063
3064
3065
3066
3067
3068
3069
3070
3071
3072
3073
3074
3075
3076
3077
3078
if not modules then modules = { } end modules ['luaotfload-database'] = {
    version   = "2.3b",
    comment   = "companion to luaotfload.lua",
    author    = "Khaled Hosny, Elie Roux, Philipp Gesang",
    copyright = "Luaotfload Development Team",
    license   = "GNU GPL v2"
}

--- TODO: if the specification is an absolute filename with a font not in the
--- database, add the font to the database and load it. There is a small
--- difficulty with the filenames of the TEXMF tree that are referenced as
--- relative paths...

local lpeg = require "lpeg"

local P, R, S, lpegmatch
    = lpeg.P, lpeg.R, lpeg.S, lpeg.match

local C, Cc, Cf, Cg, Cs, Ct
    = lpeg.C, lpeg.Cc, lpeg.Cf, lpeg.Cg, lpeg.Cs, lpeg.Ct

--- Luatex builtins
local load                    = load
local next                    = next
local pcall                   = pcall
local require                 = require
local tonumber                = tonumber
local unpack                  = table.unpack

local fontloaderinfo          = fontloader.info
local fontloaderclose         = fontloader.close
local fontloaderopen          = fontloader.open
local fontloaderto_table      = fontloader.to_table
local iolines                 = io.lines
local ioopen                  = io.open
local kpseexpand_path         = kpse.expand_path
local kpseexpand_var          = kpse.expand_var
local kpsefind_file           = kpse.find_file
local kpselookup              = kpse.lookup
local kpsereadable_file       = kpse.readable_file
local lfsattributes           = lfs.attributes
local lfschdir                = lfs.chdir
local lfscurrentdir           = lfs.currentdir
local lfsdir                  = lfs.dir
local mathabs                 = math.abs
local mathmin                 = math.min
local osgettimeofday          = os.gettimeofday
local osremove                = os.remove
local stringfind              = string.find
local stringformat            = string.format
local stringgmatch            = string.gmatch
local stringgsub              = string.gsub
local stringlower             = string.lower
local stringsub               = string.sub
local stringupper             = string.upper
local tableconcat             = table.concat
local tablesort               = table.sort
local texiowrite_nl           = texio.write_nl
local utf8gsub                = unicode.utf8.gsub
local utf8lower               = unicode.utf8.lower

--- these come from Lualibs/Context
local getwritablepath         = caches.getwritablepath
local filebasename            = file.basename
local filecollapsepath        = file.collapsepath or file.collapse_path
local filedirname             = file.dirname
local fileextname             = file.extname
local fileiswritable          = file.iswritable
local filejoin                = file.join
local filenameonly            = file.nameonly
local filereplacesuffix       = file.replacesuffix
local filesplitpath           = file.splitpath or file.split_path
local filesuffix              = file.suffix
local lfsisdir                = lfs.isdir
local lfsisfile               = lfs.isfile
local lfsmkdirs               = lfs.mkdirs
local stringis_empty          = string.is_empty
local stringsplit             = string.split
local stringstrip             = string.strip
local tableappend             = table.append
local tablecopy               = table.copy
local tablefastcopy           = table.fastcopy
local tabletofile             = table.tofile
local tabletohash             = table.tohash

--- the font loader namespace is “fonts”, same as in Context
--- we need to put some fallbacks into place for when running
--- as a script
fonts                = fonts          or { }
fonts.names          = fonts.names    or { }
fonts.definers       = fonts.definers or { }

local names          = fonts.names

config                         = config or { }
config.luaotfload              = config.luaotfload or { }
config.luaotfload.resolver     = config.luaotfload.resolver or "normal"
config.luaotfload.formats      = config.luaotfload.formats or "otf,ttf,ttc,dfont"

if config.luaotfload.update_live ~= false then
    --- this option allows for disabling updates
    --- during a TeX run
    config.luaotfload.update_live = true
end

names.version        = 2.4
names.data           = nil      --- contains the loaded database
names.lookups        = nil      --- contains the lookup cache

names.path           = { index = { }, lookups = { } }
names.path.globals   = {
    prefix           = "", --- writable_path/names_dir
    names_dir        = config.luaotfload.names_dir or "names",
    index_file       = config.luaotfload.index_file
                    or "luaotfload-names.lua",
    lookups_file     = "luaotfload-lookup-cache.lua",
}

--- string -> (string * string)
local make_luanames = function (path)
    return filereplacesuffix(path, "lua"),
           filereplacesuffix(path, "luc")
end

local report = logs.names_report

names.patterns          = { }
local patterns          = names.patterns

local trailingslashes   = P"/"^1 * P(-1)
local stripslashes      = C((1 - trailingslashes)^0)
patterns.stripslashes   = stripslashes

local comma             = P","
local noncomma          = 1-comma
local splitcomma        = Ct((C(noncomma^1) + comma)^1)
patterns.splitcomma     = splitcomma

--[[doc--
    We use the functions in the cache.* namespace that come with the
    fontloader (see luat-basics-gen). it’s safe to use for the most part
    since most checks and directory creations are already done. It
    uses TEXMFCACHE or TEXMFVAR as starting points.

    There is one quirk, though: ``getwritablepath()`` will always
    assume that files in subdirectories of the cache tree are writable.
    It gives no feedback at all if it fails to open a file in write
    mode. This may cause trouble when the index or lookup cache were
    created by different user.
--doc]]--

if caches then
    local globals   = names.path.globals
    local names_dir = globals.names_dir

    prefix = getwritablepath (names_dir, "")
    if not prefix then
        luaotfload.error
            ("Impossible to find a suitable writeable cache...")
    else
        prefix = lpegmatch (stripslashes, prefix)
        report ("log", 0, "db",
                "root cache directory is " .. prefix)
    end

    globals.prefix     = prefix
    local lookups      = names.path.lookups
    local index        = names.path.index
    local lookups_file = filejoin (prefix, globals.lookups_file)
    local index_file   = filejoin (prefix, globals.index_file)
    lookups.lua, lookups.luc = make_luanames (lookups_file)
    index.lua, index.luc     = make_luanames (index_file)
else --- running as script, inject some dummies
    caches = { }
    logs   = { report = function () end }
end


--[[doc--
Auxiliary functions
--doc]]--

--- fontnames contain all kinds of garbage; as a precaution we
--- lowercase and strip them of non alphanumerical characters

--- string -> string

local invalidchars = "[^%a%d]"

local sanitize_fontname = function (str)
    if str ~= nil then
        str = utf8gsub (utf8lower (str), invalidchars, "")
        return str
    end
    return nil
end

local sanitize_fontnames = function (rawnames)
    local result = { }
    for category, namedata in next, rawnames do

        if type (namedata) == "string" then
            result [category] = utf8gsub (utf8lower (namedata),
                                          invalidchars,
                                          "")
        else
            local target = { }
            for field, name in next, namedata do
                target [field] = utf8gsub (utf8lower (name),
                                        invalidchars,
                                        "")
            end
            result [category] = target
        end
    end
    return result
end

local find_files_indeed
find_files_indeed = function (acc, dirs, filter)
    if not next (dirs) then --- done
        return acc
    end

    local pwd   = lfscurrentdir ()
    local dir   = dirs[#dirs]
    dirs[#dirs] = nil

    if lfschdir (dir) then
        lfschdir (pwd)

        local newfiles = { }
        for ent in lfsdir (dir) do
            if ent ~= "." and ent ~= ".." then
                local fullpath = dir .. "/" .. ent
                if filter (fullpath) == true then
                    if lfsisdir (fullpath) then
                        dirs[#dirs+1] = fullpath
                    elseif lfsisfile (fullpath) then
                        newfiles[#newfiles+1] = fullpath
                    end
                end
            end
        end
        return find_files_indeed (tableappend (acc, newfiles),
                                  dirs, filter)
    end
    --- could not cd into, so we skip it
    return find_files_indeed (acc, dirs, filter)
end

local dummyfilter = function () return true end

--- the optional filter function receives the full path of a file
--- system entity. a filter applies if the first argument it returns is
--- true.

--- string -> function? -> string list
local find_files = function (root, filter)
    if lfsisdir (root) then
        return find_files_indeed ({}, { root }, filter or dummyfilter)
    end
end


--[[doc--
This is a sketch of the luaotfload db:

    type dbobj = {
        families    : familytable;
        filenames   : filemap;
        status      : filestatus;
        mappings    : fontentry list;
        meta        : metadata;
        names       : namedata; // TODO: check for relevance after db is finalized
    }
    and familytable = {
        local  : (format, familyentry) hash; // specified with include dir
        texmf  : (format, familyentry) hash;
        system : (format, familyentry) hash;
    }
    and familyentry = {
        regular     : sizes;
        italic      : sizes;
        bold        : sizes;
        bolditalic  : sizes;
    }
    and sizes = {
        default : int;              // points into mappings or names
        optical : (int, int) list;  // design size -> index entry
    }
    and metadata = {
        formats     : string list; // { "otf", "ttf", "ttc", "dfont" }
        statistics  : TODO;
        version     : float;
    }
    and filemap = {
        base : {
            local  : (string, int) hash; // basename -> idx
            system : (string, int) hash;
            texmf  : (string, int) hash;
        };
        bare : {
            local  : (string, (string, int) hash) hash; // location -> (barename -> idx)
            system : (string, (string, int) hash) hash;
            texmf  : (string, (string, int) hash) hash;
        };
        full : (int, string) hash; // idx -> full path
    }
    and fontentry = {
        barename    : string;
        familyname  : string;
        filename    : string;
        fontname    : string; // <- metadata
        fullname    : string; // <- metadata
        sanitized   : {
            family         : string;
            fontstyle_name : string; // <- new in 2.4
            fontname       : string; // <- metadata
            fullname       : string; // <- namedata.names
            metafamily     : string;
            pfullname      : string;
            prefmodifiers  : string;
            psname         : string;
            subfamily      : string;
        };
        size         : int list;
        slant        : int;
        subfont      : int;
        location     : local | system | texmf;
        weight       : int;
        width        : int;
        units_per_em : int;         // mainly 1000, but also 2048 or 256
    }
    and filestatus = (string,       // fullname
                      { index       : int list; // pointer into mappings
                        timestamp   : int;      }) dict

beware that this is a reconstruction and may be incomplete.

mtx-fonts has in names.tma:

    type names = {
        cache_uuid    : uuid;
        cache_version : float;
        datastate     : uuid list;
        fallbacks     : (filetype, (basename, int) hash) hash;
        families      : (basename, int list) hash;
        files         : (filename, fullname) hash;
        indices       : (fullname, int) hash;
        mappings      : (filetype, (basename, int) hash) hash;
        names         : ? (empty hash) ?;
        rejected      : (basename, int) hash;
        specifications: fontentry list;
    }
    and fontentry = {
        designsize    : int;
        familyname    : string;
        filename      : string;
        fontname      : string;
        format        : string;
        fullname      : string;
        maxsize       : int;
        minsize       : int;
        modification  : int;
        rawname       : string;
        style         : string;
        subfamily     : string;
        variant       : string;
        weight        : string;
        width         : string;
    }

--doc]]--

local initialize_namedata = function (formats) --- returns dbobj
    return {
        families        = {
            ["local"]  = { },
            system     = { },
            texmf      = { },
        },
        status          = { }, -- was: status; map abspath -> mapping
        mappings        = { }, -- TODO: check if still necessary after rewrite
        names           = { },
--      filenames       = { }, -- created later
        meta            = {
            formats    = formats,
            statistics = { },
            version    = names.version,
        },
    }
end

--- When loading a lua file we try its binary complement first, which
--- is assumed to be located at an identical path, carrying the suffix
--- .luc.

--- string -> (string * table)
local load_lua_file = function (path)
    local foundname = filereplacesuffix(path, "luc")

    local fh = ioopen(foundname, "rb") -- try bin first
    if fh then
        local chunk = fh:read"*all"
        fh:close()
        code = load(chunk, "b")
    end

    if not code then --- fall back to text file
        foundname = filereplacesuffix(path, "lua")
        fh = ioopen(foundname, "rb")
        if fh then
            local chunk = fh:read"*all"
            fh:close()
            code = load(chunk, "t")
        end
    end

    if not code then return nil, nil end
    return foundname, code()
end

--- define locals in scope
local crude_file_lookup
local crude_file_lookup_verbose
local find_closest
local flush_lookup_cache
local ot_fullinfo
local t1_fullinfo
local load_names
local load_lookups
local read_blacklist
local read_fonts_conf
local reload_db
local resolve
local resolve_cached
local resolve_fullpath
local save_names
local save_lookups
local update_names
local get_font_filter
local set_font_filter

--- state of the database
local fonts_loaded   = false
local fonts_reloaded = false

--- limit output when approximate font matching (luaotfload-tool -F)
local fuzzy_limit = 1 --- display closest only

--- bool? -> dbobj
load_names = function (dry_run)
    local starttime = osgettimeofday ()
    local foundname, data = load_lua_file (names.path.index.lua)

    if data then
        report ("both", 2, "db",
                "Font names database loaded", "%s", foundname)
        report ("info", 3, "db", "Loading took %0.f ms",
                1000 * (osgettimeofday () - starttime))

        local db_version, nms_version = data.meta.version, names.version
        if db_version ~= nms_version then
            report ("both", 0, "db",
                    [[Version mismatch; expected %4.3f, got %4.3f]],
                    nms_version, db_version)
            if not fonts_reloaded then
                report ("both", 0, "db", [[Force rebuild]])
                data = update_names ({ }, true, false)
                if not data then
                    report ("both", 0, "db",
                            "Database creation unsuccessful.")
                end
            end
        end
    else
        report ("both", 0, "db",
                [[Font names database not found, generating new one.]])
        report ("both", 0, "db",
                [[This can take several minutes; please be patient.]])
        data = update_names (initialize_namedata (get_font_filter ()),
                             nil, dry_run)
        if not success then
            report ("both", 0, "db", "Database creation unsuccessful.")
        end
    end
    fonts_loaded = true
    return data
end

--- unit -> dbobj
load_lookups = function ( )
    local foundname, data = load_lua_file(names.path.lookups.lua)
    if data then
        report("both", 3, "cache",
               "Lookup cache loaded (%s)", foundname)
    else
        report("both", 1, "cache",
               "No lookup cache, creating empty.")
        data = { }
    end
    return data
end

local style_synonyms = { set = { } }
do
    local combine = function (ta, tb)
        local result = { }
        for i=1, #ta do
            for j=1, #tb do
                result[#result+1] = ta[i] .. tb[j]
            end
        end
        return result
    end

    --- read this: http://blogs.adobe.com/typblography/2008/05/indesign_font_conflicts.html
    --- tl;dr: font style synonyms are unreliable.
    ---
    --- Context matches font names against lists of known identifiers
    --- for weight, style, width, and variant, so that including
    --- the family name there are five dimensions for choosing a
    --- match. The sad thing is, while this is a decent heuristic it
    --- makes no sense to imitate it in luaotfload because the user
    --- interface must fit into the much more limited Xetex scheme that
    --- distinguishes between merely four style categories (variants):
    --- “regular”, “italic”, “bold”, and “bolditalic”. As a result,
    --- some of the styles are lumped together although they can differ
    --- significantly (like “medium” and “bold”).

    --- Xetex (XeTeXFontMgr.cpp) appears to recognize only “plain”,
    --- “normal”, and “roman” as synonyms for “regular”.
    local list = {
        regular    = { "normal",         "roman",
                       "plain",          "book",
                       "light",          "extralight",
                       "ultralight", },
        bold       = { "demi",           "demibold",
                       "semibold",       "boldregular",
                       "medium",         "mediumbold",
                       "ultrabold",      "extrabold",
                       "heavy",          "black",
                       "bold", },
        italic     = { "regularitalic",  "normalitalic",
                       "oblique",        "slanted",
                       "italic", },
    }

    list.bolditalic     = combine(list.bold, list.italic)
    style_synonyms.list = list

    for category, synonyms in next, style_synonyms.list do
        style_synonyms.set[category] = tabletohash(synonyms, true)
    end
end

local type1_formats = { "tfm", "ofm", }

local dummy_findfile = resolvers.findfile -- from basics-gen

--- filemap -> string -> string -> (string | bool)
local verbose_lookup = function (data, kind, filename)
    local found = data[kind][filename]
    if found ~= nil then
        found = data.full[found]
        if found == nil then --> texmf
            report("info", 0, "db",
                "Crude file lookup: req=%s; hit=%s => kpse",
                filename, kind)
            found = dummy_findfile(filename)
        else
            report("info", 0, "db",
                "Crude file lookup: req=%s; hit=%s; ret=%s",
                filename, kind, found)
        end
        return found
    end
    return false
end

--- string -> (string * string * bool)
crude_file_lookup_verbose = function (filename)
    if not names.data then names.data = load_names() end
    local data      = names.data
    local mappings  = data.mappings
    local filenames = data.filenames
    local found

    --- look up in db first ...
    found = verbose_lookup(filenames, "bare", filename)
    if found then
        return found, nil, true
    end
    found = verbose_lookup(filenames, "base", filename)
    if found then
        return found, nil, true
    end

    --- ofm and tfm, returns pair
    for i=1, #type1_formats do
        local format = type1_formats[i]
        if resolvers.findfile(filename, format) then
            return file.addsuffix(filename, format), format, true
        end
    end
    return filename, nil, false
end

--- string -> (string * string * bool)
crude_file_lookup = function (filename)
    if not names.data then names.data = load_names() end
    local data      = names.data
    local mappings  = data.mappings
    local filenames = data.filenames

    local found

    found = filenames.base[filename]
         or filenames.bare[filename]

    if found then
        found = filenames.full[found]
        if found == nil then
            found = dummy_findfile(filename)
        end
        return found or filename, nil, true
    end

    for i=1, #type1_formats do
        local format = type1_formats[i]
        if resolvers.findfile(filename, format) then
            return file.addsuffix(filename, format), format, true
        end
    end

    return filename, nil, false
end

--[[doc--
Existence of the resolved file name is verified differently depending
on whether the index entry has a texmf flag set.
--doc]]--

local get_font_file = function (fullnames, entry)
    local basename = entry.basename
    if entry.location == "texmf" then
        if kpselookup(basename) then
            return true, basename, entry.subfont
        end
    else
        local fullname = fullnames[entry.index]
        if lfsisfile(fullname) then
            return true, basename, entry.subfont
        end
    end
    return false
end

--[[doc--
We need to verify if the result of a cached lookup actually exists in
the texmf or filesystem.
--doc]]--

local verify_font_file = function (basename)
    if not names.data then names.data = load_names() end
    local filenames = names.data.filenames
    local idx = filenames.base[basename]
    if not idx then
        return false
    end

    --- firstly, check filesystem
    local fullname = filenames.full[idx]
    if fullname and lfsisfile(fullname) then
        return true
    end

    --- secondly, locate via kpathsea
    if kpsefind_file(basename) then
        return true
    end

    return false
end

--[[doc--
Lookups can be quite costly, more so the less specific they are.
Even if we find a matching font eventually, the next time the
user compiles Eir document E will have to stand through the delay
again.
Thus, some caching of results -- even between runs -- is in order.
We’ll just store successful name: lookups in a separate cache file.

type lookup_cache = (string, (string * num)) dict

Complete, needs testing:
 ×  1) add cache to dbobj
 ×  2) wrap lookups in cached versions
 ×  3) make caching optional (via the config table) for debugging
 ×  4) make names_update() cache aware (nil if “force”)
 ×  5) add logging
 ×  6) add cache control to luaotfload-tool
 ×  7) incr db version (now 2.203)
 ×  8) save cache only at the end of a run

The spec is modified in place (ugh), so we’ll have to catalogue what
fields actually influence its behavior.

Idk what the “spec” resolver is for.

        lookup      inspects            modifies
        file:       name                forced, name
        name:*      name, style, sub,   resolved, sub, name, forced
                    optsize, size
        spec:       name, sub           resolved, sub, name, forced

* name: contains both the name resolver from luatex-fonts and resolve()
  below

From my reading of font-def.lua, what a resolver does is
basically rewrite the “name” field of the specification record
with the resolution.
Also, the fields “resolved”, “sub”, “force” etc. influence the outcome.

--doc]]--

local concat_char = "#"
local hash_fields = {
    --- order is important
    "specification", "style", "sub", "optsize", "size",
}
local n_hash_fields = #hash_fields

--- spec -> string
local hash_request = function (specification)
    local key = { } --- segments of the hash
    for i=1, n_hash_fields do
        local field = specification[hash_fields[i]]
        if field then
            key[#key+1] = field
        end
    end
    return tableconcat(key, concat_char)
end

--- 'a -> 'a -> table -> (string * int|boolean * boolean)
resolve_cached = function (_, _, specification)
    if not names.lookups then names.lookups = load_lookups() end
    local request = hash_request(specification)
    report("both", 4, "cache", "Looking for %q in cache ...",
           request)

    local found = names.lookups[request]

    --- case 1) cache positive ----------------------------------------
    if found then --- replay fields from cache hit
        report("info", 4, "cache", "Found!")
        local basename = found[1]
        --- check the presence of the file in case it’s been removed
        local success = verify_font_file(basename)
        if success == true then
            return basename, found[2], true
        end
        report("both", 4, "cache", "Cached file not found; resolving again")
    else
        report("both", 4, "cache", "Not cached; resolving")
    end

    --- case 2) cache negative ----------------------------------------
    --- first we resolve normally ...
    local filename, subfont, success = resolve(nil, nil, specification)
    if not success then return filename, subfont, false end
    --- ... then we add the fields to the cache ... ...
    local entry = { filename, subfont }
    report("both", 4, "cache", "New entry: %s", request)
    names.lookups[request] = entry

    --- obviously, the updated cache needs to be stored.
    --- TODO this should trigger a save only once the
    ---      document is compiled (finish_pdffile callback?)
    report("both", 5, "cache", "Saving updated cache")
    local success = save_lookups()
    if not success then --- sad, but not critical
        report("both", 0, "cache", "Could not write to cache")
    end
    return filename, subfont, true
end

--- this used to be inlined; with the lookup cache we don’t
--- have to be parsimonious wrt function calls anymore
--- “found” is the match accumulator
local add_to_match = function (found, size, face)

    local continue = true

    local optsize = face.size

    if optsize and next (optsize) then
        local dsnsize, maxsize, minsize
        dsnsize = optsize[1]
        maxsize = optsize[2]
        minsize = optsize[3]

        if size ~= nil
        and (dsnsize == size or (size > minsize and size <= maxsize))
        then
            found[1] = face
            continue = false ---> break
        else
            found[#found+1] = face
        end
    else
        found[1] = face
        continue = false ---> break
    end

    return found, continue
end

--[[doc--

Luatex-fonts, the font-loader package luaotfload imports, comes with
basic file location facilities (see luatex-fonts-syn.lua).
However, not only does the builtin functionality rely on Context’s font
name database, it is also too limited to be of more than basic use.
For this reason, luaotfload supplies its own resolvers that accesses
the font database created by the luaotfload-tool script.

--doc]]--


---
--- the request specification has the fields:
---
---   · features: table
---     · normal: set of { ccmp clig itlc kern liga locl mark mkmk rlig }
---     · ???
---   · forced:   string
---   · lookup:   "name"
---   · method:   string
---   · name:     string
---   · resolved: string
---   · size:     int
---   · specification: string (== <lookup> ":" <name>)
---   · sub:      string
---
--- The “size” field deserves special attention: if its value is
--- negative, then it actually specifies a scalefactor of the
--- design size of the requested font. This happens e.g. if a font is
--- requested without an explicit “at size”. If the font is part of a
--- larger collection with different design sizes, this complicates
--- matters a bit: Normally, the resolver prefers fonts that have a
--- design size as close as possible to the requested size. If no
--- size specified, then the design size is implied. But which design
--- size should that be? Xetex appears to pick the “normal” (unmarked)
--- size: with Adobe fonts this would be the one that is neither
--- “caption” nor “subhead” nor “display” &c ... For fonts by Adobe this
--- seems to be the one that does not receive a “prefmodifiers” field.
--- (IOW Adobe uses the “prefmodifiers” field to encode the design size
--- in more or less human readable format.) However, this is not true
--- of LM and EB Garamond. As this matters only where there are
--- multiple design sizes to a given font/style combination, we put a
--- workaround in place that chooses that unmarked version.

---
--- the first return value of “resolve” is the file name of the
--- requested font (string)
--- the second is of type bool or string and indicates the subfont of a
--- ttc
---
--- 'a -> 'a -> table -> (string * string | bool * bool)
---

resolve = function (_, _, specification) -- the 1st two parameters are used by ConTeXt
    if not fonts_loaded then names.data = load_names() end
    local data = names.data

    local name  = sanitize_fontname (specification.name)
    local style = sanitize_fontname (specification.style) or "regular"

    local askedsize

    if specification.optsize then
        askedsize = tonumber(specification.optsize)
    else
        local specsize = specification.size
        if specsize and specsize >= 0 then
            askedsize = specsize / 65536
        end
    end

    if type(data) ~= "table" then
         --- this catches a case where load_names() doesn’t
         --- return a database object, which can happen only
         --- in case there is valid Lua code in the database,
         --- but it’s not a table, e.g. it contains an integer.
        if not fonts_reloaded then
            return reload_db("invalid database; not a table",
                             resolve, nil, nil, specification)
        end
        --- unsucessfully reloaded; bail
        return specification.name, false, false
    end

    if not data.mappings then
        if not fonts_reloaded then
            return reload_db("invalid database; missing font mapping",
                             resolve, nil, nil, specification)
        end
        return specification.name, false, false
    end

    local synonym_set       = style_synonyms.set
    local stylesynonyms     = synonym_set[style]
    local regularsynonyms   = synonym_set.regular

    local exact      = { } --> collect exact style matches
    local synonymous = { } --> collect matching style synonyms
    local fallback         --> e.g. non-matching style (fontspec is anal about this)
    local candidates = { } --> secondary results, incomplete matches

    for n, face in next, data.mappings do
        local family, metafamily
        local prefmodifiers, fontstyle_name, subfamily
        local psname, fullname, fontname, pfullname

        local facenames = face.sanitized
        if facenames then
            family          = facenames.family
            subfamily       = facenames.subfamily
            fontstyle_name  = facenames.fontstyle_name
            prefmodifiers   = facenames.prefmodifiers or fontstyle_name or subfamily
            fullname        = facenames.fullname
            psname          = facenames.psname
            fontname        = facenames.fontname
            pfullname       = facenames.pfullname
            metafamily      = facenames.metafamily
        end
        fontname    = fontname  or sanitize_fontname (face.fontname)
        pfullname   = pfullname or sanitize_fontname (face.fullname)

        if     name == family
            or name == metafamily
        then
            if     style == prefmodifiers
                or style == fontstyle_name
            then
                local continue
                exact, continue = add_to_match(exact, askedsize, face)
                if continue == false then break end
            elseif style == subfamily then
                exact = add_to_match(exact, askedsize, face)
            elseif stylesynonyms and stylesynonyms[prefmodifiers]
                or regularsynonyms[prefmodifiers]
            then
                --- treat synonyms for prefmodifiers as first-class
                --- (needed to prioritize DejaVu Book over Condensed)
                exact = add_to_match(exact, askedsize, face)
            elseif name == fullname
                or name == pfullname
                or name == fontname
                or name == psname
            then
                synonymous = add_to_match(synonymous, askedsize, face)
            elseif stylesynonyms and stylesynonyms[subfamily]
                or regularsynonyms[subfamily]
            then
                synonymous = add_to_match(synonymous, askedsize, face)
            elseif prefmodifiers == "regular"
                or subfamily     == "regular" then
                fallback = face
            else --- mark as last straw but continue
                candidates[#candidates+1] = face
            end
        else
            if name == fullname
            or name == pfullname
            or name == fontname
            or name == psname then
                local continue
                exact, continue = add_to_match(exact, askedsize, face)
                if continue == false then break end
            end
        end
    end

    local found
    if next(exact) then
        found = exact
    else
        found = synonymous
    end

    --- this is a monster
    if #found == 1 then
        --- “found” is really synonymous with “registered in the db”.
        local entry = found[1]
        local success, filename, subfont
            = get_font_file(data.filenames.full, entry)
        if success == true then
            report("log", 0, "resolve",
                "Font family='%s', subfamily='%s' found: %s",
                name, style, filename
            )
            return filename, subfont, true
        end

    elseif #found > 1 then
        -- we found matching font(s) but not in the requested optical
        -- sizes, so we loop through the matches to find the one with
        -- least difference from the requested size.
        local match

        if askedsize then  --- choose by design size
            local closest
            local least = math.huge -- initial value is infinity

            for i, face in next, found do
                local dsnsize = face.size and face.size [1] or 0
                local difference = mathabs (dsnsize - askedsize)
                if difference < least then
                    closest = face
                    least   = difference
                end
            end

            match = closest
        else --- choose “unmarked” match, for Adobe fonts this
             --- is the one without a “prefmodifiers” field.
            match = found [1] --- fallback
            for i, face in next, found do
                if not face.sanitized.prefmodifiers then
                    match = face
                    break
                end
            end
        end

        local success, filename, subfont
            = get_font_file(data.filenames.full, match)
        if success == true then
            report("log", 0, "resolve",
                "Font family='%s', subfamily='%s' found: %s",
                name, style, filename
            )
            return filename, subfont, true
        end

    elseif fallback then
        local success, filename, subfont
            = get_font_file(data.filenames.full, fallback)
        if success == true then
            report("log", 0, "resolve",
                "No exact match for request %s; using fallback",
                specification.specification
            )
            report("log", 0, "resolve",
                "Font family='%s', subfamily='%s' found: %s",
                name, style, filename
            )
            return filename, subfont, true
        end
    elseif next(candidates) then
        --- pick the first candidate encountered
        local entry = candidates[1]
        local success, filename, subfont
            = get_font_file(data.filenames.full, entry)
        if success == true then
            report("log", 0, "resolve",
                "Font family='%s', subfamily='%s' found: %s",
                name, style, filename
            )
            return filename, subfont, true
        end
    end

    --- no font found so far
    if not fonts_reloaded then
        --- last straw: try reloading the database
        return reload_db(
            "unresolved font name: '" .. name .. "'",
            resolve, nil, nil, specification
        )
    end

    --- else, default to requested name
    return specification.name, false, false
end --- resolve()

resolve_fullpath = function (fontname, ext) --- getfilename()
    if not fonts_loaded then
        names.data = load_names()
    end
    local filenames = names.data.filenames
    local idx = filenames.base[fontname]
             or filenames.bare[fontname]
    if idx then
        return filenames.full[idx]
    end
    return ""
end

--- when reload is triggered we update the database
--- and then re-run the caller with the arg list

--- string -> ('a -> 'a) -> 'a list -> 'a
reload_db = function (why, caller, ...)
    local namedata  = names.data
    local formats   = tableconcat (namedata.meta.formats, ",")

    report ("both", 1, "db",
            "Reload initiated (formats: %s); reason: %q",
            formats, why)

    set_font_filter (formats)
    namedata = update_names (namedata, false, false)

    if namedata then
        fonts_reloaded = true
        names.data = namedata
        return caller (...)
    end

    report ("both", 0, "db", "Database update unsuccessful.")
end

--- string -> string -> int
local iterative_levenshtein = function (s1, s2)

  local costs = { }
  local len1, len2 = #s1, #s2

  for i = 0, len1 do
    local last = i
    for j = 0, len2 do
      if i == 0 then
        costs[j] = j
      else
        if j > 0 then
          local current = costs[j-1]
          if stringsub(s1, i, i) ~= stringsub(s2, j, j) then
            current = mathmin(current, last, costs[j]) + 1
          end
          costs[j-1] = last
          last = current
        end
      end
    end
    if i > 0 then costs[len2] = last end
  end

  return costs[len2]--- lower right has the distance
end

--- string -> int -> bool
find_closest = function (name, limit)
    local name     = sanitize_fontname (name)
    limit          = limit or fuzzy_limit

    if not fonts_loaded then names.data = load_names() end

    local data = names.data

    if type(data) ~= "table" then
        if not fonts_reloaded then
            return reload_db("no database", find_closest, name)
        end
        return false
    end
    local by_distance   = { } --- (int, string list) dict
    local distances     = { } --- int list
    local cached        = { } --- (string, int) dict
    local mappings      = data.mappings
    local n_fonts       = #mappings

    for n = 1, n_fonts do
        local current    = mappings[n]
        local cnames     = current.sanitized
        --[[
            This is simplistic but surpisingly fast.
            Matching is performed against the “fullname” field
            of a db record in preprocessed form. We then store the
            raw “fullname” at its edit distance.
            We should probably do some weighting over all the
            font name categories as well as whatever agrep
            does.
        --]]
        if cnames then
            local fullname, sfullname = current.fullname, cnames.fullname

            local dist = cached[sfullname]--- maybe already calculated
            if not dist then
                dist = iterative_levenshtein(name, sfullname)
                cached[sfullname] = dist
            end
            local namelst = by_distance[dist]
            if not namelst then --- first entry
                namelst = { fullname }
                distances[#distances+1] = dist
            else --- append
                namelst[#namelst+1] = fullname
            end
            by_distance[dist] = namelst
        end
    end

    --- print the matches according to their distance
    local n_distances = #distances
    if n_distances > 0 then --- got some data
        tablesort(distances)
        limit = mathmin(n_distances, limit)
        report(false, 1, "query",
               "Displaying %d distance levels", limit)

        for i = 1, limit do
            local dist     = distances[i]
            local namelst  = by_distance[dist]
            report(false, 0, "query",
                   "Distance from \"" .. name .. "\": " .. dist
                .. "\n    " .. tableconcat(namelst, "\n    ")
            )
        end

        return true
    end
    return false
end --- find_closest()

local load_font_file = function (filename, subfont)
    local rawfont, _msg = fontloaderopen (filename, subfont)
    if not rawfont then
        report ("log", 1, "db", "ERROR: failed to open %s", filename)
        return
    end

    local metadata = fontloaderto_table (rawfont)
    fontloaderclose (rawfont)

    metadata.glyphs     = nil
    metadata.subfonts   = nil
    metadata.gpos       = nil
    metadata.gsub       = nil
    metadata.lookups    = nil

    collectgarbage "collect"

    return metadata
end

--- rawdata -> (int * int * int | bool)

local get_size_info = function (metadata)
    local design_size         = metadata.design_size
    local design_range_top    = metadata.design_range_top
    local design_range_bottom = metadata.design_range_bottom

    local fallback_size = design_size         ~= 0 and design_size
                       or design_range_bottom ~= 0 and design_range_bottom
                       or design_range_top    ~= 0 and design_range_top

    if fallback_size then
        design_size         = (design_size         or fallback_size) / 10
        design_range_top    = (design_range_top    or fallback_size) / 10
        design_range_bottom = (design_range_bottom or fallback_size) / 10
        return {
            design_size, design_range_top, design_range_bottom,
        }
    end

    return false
end

local get_english_names = function (names, basename)

    local english_names

    if names then
        for _, raw_namedata in next, names do
            if raw_namedata.lang == "English (US)" then
                english_names = raw_namedata.names
            end
        end
    else
        -- no names table, probably a broken font
        report("log", 1, "db",
               "Broken font %s rejected due to missing names table.",
               basename)
        return nil
    end

    return english_names
end

local organize_namedata = function (metadata,
                                    english_names,
                                    basename,
                                    info)

    --print (english_names.family, "<>", english_names.preffamilyname)
    local fontnames = {
        --- see
        --- https://developer.apple.com/fonts/TTRefMan/RM06/Chap6name.html
        --- http://www.microsoft.com/typography/OTSPEC/name.htm#NameIDs
        english = {
            --- where a “compatfull” field is given, the value of “fullname” is
            --- either identical or differs by separating the style
            --- with a hyphen and omitting spaces. (According to the
            --- spec, “compatfull” is “Macintosh only”.)
            --- Of the three “fullname” fields, this one appears to be the one
            --- with the entire name given in a legible,
            --- non-abbreviated fashion, for most fonts at any rate.
            --- However, in some fonts (e.g. CMU) all three fields are
            --- identical.
            fullname      = english_names.compatfull
                         or english_names.fullname,
            --- we keep both the “preferred family” and the “family”
            --- values around since both are valid but can turn out
            --- quite differently, e.g. with Latin Modern:
            ---     preffamily: “Latin Modern Sans”,
            ---     family:     “LM Sans 10”
            preffamily    = english_names.preffamilyname,
            family        = english_names.family,
            prefmodifiers = english_names.prefmodifiers,
            subfamily     = english_names.subfamily,
            psname        = english_names.postscriptname,
        },

        metadata = {
            fullname      = metadata.fullname,
            fontname      = metadata.fontname,
            metafamily    = metadata.familyname,
        },

        info = {
            fullname      = info.fullname,
            familyname    = info.familyname,
            fontname      = info.fontname,
        },
    }

--    print (fontnames.english.fullname,
--           fontnames.metadata.fullname,
--           fontnames.info.fullname)

    if metadata.fontstyle_name then
        --- not present in all fonts, often differs from the preferred
        --- subfamily as well as subfamily fields, e.g. with LMSans10-BoldOblique:
        ---     subfamily:      “Bold Italic”
        ---     prefmodifiers:  “10 Bold Oblique”
        ---     fontstyle_name: “Bold Oblique”
        for _, name in next, metadata.fontstyle_name do
            if name.lang == 1033 then --- I hate magic numbers
                fontnames.fontstyle_name = name.name
            end
        end

        --print (fontnames.metadata.fontname, "|>", english_names.subfamily, "<>", english_names.prefmodifiers)
        --print (fontnames.metadata.fontname, "|>", english_names.subfamily, "<>", fontnames.fontstyle_name)
    end

    return {
        sanitized     = sanitize_fontnames (fontnames),
        fontname      = metadata.fontname,
        fullname      = metadata.fullname,
        familyname    = metadata.familyname,
    }

end

local organize_styledata = function (metadata, english_names, info)
    local pfminfo   = metadata.pfminfo
    local names     = metadata.names

--    print (">", pfminfo.avgwidth,
--            (metadata.italicangle == info.italicangle) and "T" or
--            string.format ("%f / %f", metadata.italicangle, info.italicangle),
--            pfminfo.width, pfminfo.weight, info.weight)
    return {
    -- see http://www.microsoft.com/typography/OTSPEC/features_pt.htm#size
        size            = get_size_info (metadata),
        weight          = {
            pfminfo.weight,                     -- integer (multiple of 100?)
            sanitize_fontname (info.weight),    -- style name
        },
        width           = pfminfo.width,
        italicangle     = metadata.italicangle,
--        italicangle     = {
--            metadata.italicangle,   -- float
--            info.italicangle,       -- truncated to integer point size?
--        },
    --- this is for querying, see www.ntg.nl/maps/40/07.pdf for details
        units_per_em    = metadata.units_per_em,
        version         = metadata.version,
    }
end

--[[doc--
The data inside an Opentype font file can be quite heterogeneous.
Thus in order to get the relevant information, parts of the original
table as returned by the font file reader need to be relocated.
--doc]]--

--- string -> int -> bool -> string -> fontentry

ot_fullinfo = function (filename,
                        subfont,
                        location,
                        basename,
                        format,
                        info)

    local metadata = load_font_file (filename, subfont)
    if not metadata then
        return nil
    end

    local english_names = get_english_names (metadata.names, basename)
    local namedata      = organize_namedata (metadata,
                                             english_names,
                                             basename,
                                             info)
    local style         = organize_styledata (metadata,
                                              english_names,
                                              info)

    return {
        file            = { base        = basename,
                            full        = filename,
                            subfont     = subfont,
                            location    = location or "system" },
        format          = format,
        names           = namedata,
        style           = style,
        units_per_em    = metadata.units_per_em,
        version         = metadata.version,
    }
end

--[[doc--

    Type1 font inspector. In comparison with OTF, PFB’s contain a good
    deal less name fields which makes it tricky in some parts to find a
    meaningful representation for the database.

    Good read: http://www.adobe.com/devnet/font/pdfs/5004.AFM_Spec.pdf

--doc]]--

--- string -> int -> bool -> string -> fontentry

t1_fullinfo = function (filename, _subfont, location, basename, format)
    local namedata = { }
    local metadata = load_font_file (filename)

    local fontname      = metadata.fontname
    local fullname      = metadata.fullname
    local familyname    = metadata.familyname
    local italicangle   = metadata.italicangle
    local weight        = metadata.weight --- string identifier

    --- we have to improvise and detect whether we deal with
    --- italics since pfb fonts don’t come with a “subfamily”
    --- field
    local style
    if italicangle == 0 then
        style = false
    else
        style = "italic"
    end

    local style_synonyms_set = style_synonyms.set
    if weight then
        weight = sanitize_fontname (weight)
        local tmp = ""
        if style_synonyms_set.bold[weight] then
            tmp = "bold"
        end
        if style then
            style = tmp .. style
        else
            if style_synonyms_set.regular[weight] then
                style = "regular"
            else
                style = tmp
            end
        end
    end

    if not style or style == "" then
        style = "regular"
        --- else italic
    end

    namedata.sanitized = sanitize_fontnames ({
        fontname        = fontname,
        psname          = fullname,
        pfullname       = fullname,
        metafamily      = family,
        family          = familyname,
        subfamily       = weight,
        prefmodifiers   = style,
    })

    namedata.fontname      = fontname
    namedata.fullname      = fullname
    namedata.familyname    = familyname

    namedata.slant         = italicangle
    namedata.units_per_em  = 1000 --- ps fonts standard
    namedata.version       = metadata.version
    namedata.weight        = metadata.pfminfo.weight --- integer
    namedata.width         = metadata.pfminfo.width

    namedata.size          = false

    namedata.filename      = filename --> sys
    namedata.basename      = basename --> texmf
    namedata.format        = format
    namedata.location      = location or "system"
    namedata.subfont       = false

    return namedata
end

local loaders = {
    dfont   = ot_fullinfo,
    otf     = ot_fullinfo,
    ttc     = ot_fullinfo,
    ttf     = ot_fullinfo,

    pfb     = t1_fullinfo,
    pfa     = t1_fullinfo,
}

--- not side-effect free!

local compare_timestamps = function (fullname,
                                     currentstatus,
                                     currententrystatus,
                                     currentmappings,
                                     targetstatus,
                                     targetentrystatus,
                                     targetmappings)

    local currenttimestamp = currententrystatus
                         and currententrystatus.timestamp
    local targettimestamp  = lfsattributes (fullname, "modification")

    if targetentrystatus ~= nil
    and targetentrystatus.timestamp == targettimestamp then
        report ("log", 3, "db", "Font %q already read.", fullname)
        return false
    end

    targetentrystatus.timestamp = targettimestamp
    targetentrystatus.index     = targetentrystatus.index or { }

    if  currenttimestamp == targettimestamp
    and not targetentrystatus.index [1]
    then

        --- copy old namedata into new

        for _, currentindex in next, currententrystatus.index do

            local targetindex   = #targetentrystatus.index
            local fullinfo      = currentmappings [currentindex]
            local location      = #targetmappings + 1

            targetmappings [location]                 = fullinfo
            targetentrystatus.index [targetindex + 1] = location
        end

        report ("log", 3, "db", "Font %q already indexed.", fullname)

        return false
    end

    return true
end

local insert_fullinfo = function (fullname,
                                  basename,
                                  n_font,
                                  loader,
                                  format,
                                  location,
                                  targetmappings,
                                  targetentrystatus,
                                  info)

    local subfont = n_font and n_font - 1 or false

    local fullinfo = loader (fullname, subfont,
                             location, basename,
                             format, info)

    if not fullinfo then
        return false
    end

    local index = targetentrystatus.index [n_font]

    if not index then
        index = #targetmappings + 1
    end

    targetmappings [index]            = fullinfo
    targetentrystatus.index [n_font]  = index

    return true
end



--- we return true if the font is new or re-indexed
--- string -> dbobj -> dbobj -> bool

local read_font_names = function (fullname,
                                  currentnames,
                                  targetnames,
                                  location)

    local targetmappings        = targetnames.mappings
    local targetstatus          = targetnames.status --- by full path
    local targetentrystatus     = targetstatus [fullname]

    if targetentrystatus == nil then
        targetentrystatus        = { }
        targetstatus [fullname]  = targetentrystatus
    end

    local currentmappings       = currentnames.mappings
    local currentstatus         = currentnames.status
    local currententrystatus    = currentstatus [fullname]

    local basename              = filebasename (fullname)
    local barename              = filenameonly (fullname)
    local entryname             = fullname

    if location == "texmf" then
        entryname = basename
    end

    --- 1) skip if blacklisted

    if names.blacklist[fullname] or names.blacklist[basename] then
        report("log", 2, "db",
               "Ignoring blacklisted font %q", fullname)
        return false
    end

    --- 2) skip if known with same timestamp

    if not compare_timestamps (fullname,
                               currentstatus,
                               currententrystatus,
                               currentmappings,
                               targetstatus,
                               targetentrystatus,
                               targetmappings)
    then
        return false
    end

    --- 3) new font; choose a loader, abort if unknown

    local format    = stringlower (filesuffix (basename))
    local loader    = loaders [format] --- ot_fullinfo, t1_fullinfo

    if not loader then
        report ("both", 0, "db",
                "Unknown format: %q, skipping.", format)
        return false
    end

    --- 4) get basic info, abort if fontloader can’t read it

    local info = fontloaderinfo (fullname)

    if not info then
        report ("log", 1, "db",
                "Failed to read basic information from %q", basename)
        return false
    end


    --- 5) check for subfonts and process each of them

    if type (info) == "table" and #info > 1 then --- ttc

        local success = false --- true if at least one subfont got read

        for n_font = 1, #info do
            if insert_fullinfo (fullname, basename, n_font,
                                loader, format, location,
                                targetmappings, targetentrystatus,
                                info)
            then
                success = true
            end
        end

        return success
    end

    return insert_fullinfo (fullname, basename, false,
                            loader, format, location,
                            targetmappings, targetentrystatus,
                            info)
end

local path_normalize
do
    --- os.type and os.name are constants so we
    --- choose a normalization function in advance
    --- instead of testing with every call
    local os_type, os_name = os.type, os.name
    local filecollapsepath = filecollapsepath
    local lfsreadlink      = lfs.readlink

    --- windows and dos
    if os_type == "windows" or os_type == "msdos" then
        --- ms platfom specific stuff
        path_normalize = function (path)
            path = stringgsub(path, '\\', '/')
            path = stringlower(path)
            path = filecollapsepath(path)
            return path
        end
--[[doc--
    The special treatment for cygwin was removed with a patch submitted
    by Ken Brown.
    Reference: http://cygwin.com/ml/cygwin/2013-05/msg00006.html
--doc]]--

    else -- posix
        path_normalize = function (path)
            local dest = lfsreadlink(path)
            if dest then
                if kpsereadable_file(dest) then
                    path = dest
                elseif kpsereadable_file(filejoin(filedirname(path), dest)) then
                    path = filejoin(file.dirname(path), dest)
                else
                    -- broken symlink?
                end
            end
            path = filecollapsepath(path)
            return path
        end
    end
end

fonts.path_normalize = path_normalize

names.blacklist = { }

local blacklist   = names.blacklist
local p_blacklist --- prefixes of dirs

--- string list -> string list
local collapse_prefixes = function (lst)
    --- avoid redundancies in blacklist
    if #lst < 2 then
        return lst
    end

    tablesort(lst)
    local cur = lst[1]
    local result = { cur }
    for i=2, #lst do
        local elm = lst[i]
        if stringsub(elm, 1, #cur) ~= cur then
            --- different prefix
            cur = elm
            result[#result+1] = cur
        end
    end
    return result
end

--- string list -> string list -> (string, bool) hash_t
local create_blacklist = function (blacklist, whitelist)
    local result = { }
    local dirs   = { }

    report("info", 2, "db", "Blacklisting %d files and directories",
           #blacklist)
    for i=1, #blacklist do
        local entry = blacklist[i]
        if lfsisdir(entry) then
            dirs[#dirs+1] = entry
        else
            result[blacklist[i]] = true
        end
    end

    report("info", 2, "db", "Whitelisting %d files", #whitelist)
    for i=1, #whitelist do
        result[whitelist[i]] = nil
    end

    dirs = collapse_prefixes(dirs)

    --- build the disjunction of the blacklisted directories
    for i=1, #dirs do
        local p_dir = P(dirs[i])
        if p_blacklist then
            p_blacklist = p_blacklist + p_dir
        else
            p_blacklist = p_dir
        end
    end

    if p_blacklist == nil then
        --- always return false
        p_blacklist = Cc(false)
    end

    return result
end

--- unit -> unit
read_blacklist = function ()
    local files = {
        kpselookup ("luaotfload-blacklist.cnf",
                    {all=true, format="tex"})
    }
    local blacklist = { }
    local whitelist = { }

    if files and type(files) == "table" then
        for _,v in next, files do
            for line in iolines(v) do
                line = stringstrip(line) -- to get rid of lines like " % foo"
                local first_chr = stringsub(line, 1, 1) --- faster than find
                if first_chr == "%" or stringis_empty(line) then
                    -- comment or empty line
                elseif first_chr == "-" then
                    whitelist[#whitelist+1] = stringsub(line, 2, -1)
                else
                    local cmt = stringfind(line, "%%")
                    if cmt then
                        line = stringsub(line, 1, cmt - 1)
                    end
                    line = stringstrip(line)
                    report("log", 2, "db", "Blacklisted file %q", line)
                    blacklist[#blacklist+1] = line
                end
            end
        end
    end
    names.blacklist = create_blacklist(blacklist, whitelist)
end

local p_font_filter

do
    local current_formats = { }

    local extension_pattern = function (list)
        local pat
        for i=#list, 1, -1 do
            local e = list[i]
            if not pat then
                pat = P(e)
            else
                pat = pat + P(e)
            end
        end
        pat = pat * P(-1)
        return (1 - pat)^1 * pat
    end

    --- small helper to adjust the font filter pattern (--formats
    --- option)

    set_font_filter = function (formats)

        if not formats or type (formats) ~= "string" then
            return
        end

        if stringsub (formats, 1, 1) == "+" then -- add
            formats = lpegmatch (splitcomma, stringsub (formats, 2))
            if formats then
                current_formats = tableappend (current_formats, formats)
            end
        elseif stringsub (formats, 1, 1) == "-" then -- add
            formats = lpegmatch (splitcomma, stringsub (formats, 2))
            if formats then
                local newformats = { }
                for i = 1, #current_formats do
                    local fmt     = current_formats[i]
                    local include = true
                    for j = 1, #formats do
                        if current_formats[i] == formats[j] then
                            include = false
                            goto skip
                        end
                    end
                    newformats[#newformats+1] = fmt
                    ::skip::
                end
                current_formats = newformats
            end
        else -- set
            formats = lpegmatch (splitcomma, formats)
            if formats then
                current_formats = formats
            end
        end

        p_font_filter = extension_pattern (current_formats)
    end

    get_font_filter = function (formats)
        return tablefastcopy (current_formats)
    end

    --- initialize
    set_font_filter (config.luaotfload.formats)
end

local process_dir_tree
process_dir_tree = function (acc, dirs)
    if not next (dirs) then --- done
        return acc
    end

    local pwd   = lfscurrentdir ()
    local dir   = dirs[#dirs]
    dirs[#dirs] = nil

    if lfschdir (dir) then
        lfschdir (pwd)

        local newfiles = { }
        local blacklist = names.blacklist
        for ent in lfsdir (dir) do
            --- filter right away
            if ent ~= "." and ent ~= ".." and not blacklist[ent] then
                local fullpath = dir .. "/" .. ent
                if lfsisdir (fullpath)
                and not lpegmatch (p_blacklist, fullpath)
                then
                    dirs[#dirs+1] = fullpath
                elseif lfsisfile (fullpath) then
                    ent = stringlower (ent)

                    if lpegmatch (p_font_filter, ent) then
                        if filesuffix (ent) == "afm" then
                            --- fontloader.open() will load the afm
                            --- iff both files are in the same directory
                            local pfbpath = filereplacesuffix
                                                    (fullpath, "pfb")
                            if lfsisfile (pfbpath) then
                                newfiles[#newfiles+1] = pfbpath
                            end
                        else
                            newfiles[#newfiles+1] = fullpath
                        end
                    end

                end
            end
        end
        return process_dir_tree (tableappend (acc, newfiles), dirs)
    end
    --- cannot cd; skip
    return process_dir_tree (acc, dirs)
end

local process_dir = function (dir)
    local pwd = lfscurrentdir ()
    if lfschdir (dir) then
        lfschdir (pwd)

        local files = { }
        local blacklist = names.blacklist
        for ent in lfsdir (dir) do
            if ent ~= "." and ent ~= ".." and not blacklist[ent] then
                local fullpath = dir .. "/" .. ent
                if lfsisfile (fullpath) then
                    ent = stringlower (ent)
                    if lpegmatch (p_font_filter, ent)
                    then
                        if filesuffix (ent) == "afm" then
                            --- fontloader.open() will load the afm
                            --- iff both files are in the same
                            --- directory
                            local pfbpath = filereplacesuffix
                                                    (fullpath, "pfb")
                            if lfsisfile (pfbpath) then
                                files[#files+1] = pfbpath
                            end
                        else
                            files[#files+1] = fullpath
                        end
                    end
                end
            end
        end
        return files
    end
    return { }
end

--- string -> bool -> string list
local find_font_files = function (root, recurse)
    if lfsisdir (root) then
        if recurse == true then
            return process_dir_tree ({}, { root })
        else --- kpathsea already delivered the necessary subdirs
            return process_dir (root)
        end
    end
end

--[[doc--

    scan_dir() scans a directory and populates the list of fonts
    with all the fonts it finds.

        · dirname       : name of the directory to scan
        · currentnames  : current font db object
        · targetnames   : font db object to fill
        · dry_run       : don’t touch anything

--doc]]--

--- string -> dbobj -> dbobj -> bool -> bool -> (int * int)

local scan_dir = function (dirname, currentnames, targetnames,
                           dry_run, location)
    if lpegmatch (p_blacklist, dirname) then
        report ("both", 4, "db",
                "Skipping blacklisted directory %s", dirname)
        --- ignore
        return 0, 0
    end
    local found = find_font_files (dirname, location ~= "texmf")
    if not found then
        report ("both", 4, "db",
                "No such directory: %q; skipping.", dirname)
        return 0, 0
    end
    report ("both", 4, "db", "Scanning directory %s", dirname)

    local n_new = 0   --- total of fonts collected
    local n_found = #found
    report ("both", 5, "db", "%d font files detected", n_found)
    for j=1, n_found do
        local fullname = found[j]
        fullname = path_normalize(fullname)
        local new
        if dry_run == true then
            report ("both", 1, "db",
                    "Would have been extracting metadata from %q",
                    fullname)
        else
            report ("both", 5, "db",
                    "Extracting metadata from font %q", fullname)
            local new = read_font_names (fullname, currentnames,
                                         targetnames, location)
            if new == true then
                n_new = n_new + 1
            end
        end
    end

    report("both", 5, "db", "%d fonts found in '%s'", n_found, dirname)
    return n_found, n_new
end

--- string list -> string list
local filter_out_pwd = function (dirs)
    local result = { }
    local pwd = path_normalize (lpegmatch (stripslashes,
                                           lfscurrentdir ()))
    for i = 1, #dirs do
        --- better safe than sorry
        local dir = path_normalize (lpegmatch (stripslashes, dirs[i]))
        if not (dir == "." or dir == pwd) then
            result[#result+1] = dir
        end
    end
    return result
end

local path_separator = ostype == "windows" and ";" or ":"

--[[doc--
    scan_texmf_fonts() scans all fonts in the texmf tree through the
    kpathsea variables OPENTYPEFONTS and TTFONTS of texmf.cnf.
    The current working directory comes as “.” (texlive) or absolute
    path (miktex) and will always be filtered out.
--doc]]--

--- dbobj -> dbobj -> bool? -> (int * int)

local scan_texmf_fonts = function (currentnames, targetnames, dry_run)

    local n_scanned, n_new, fontdirs = 0, 0
    local osfontdir = kpseexpand_path "$OSFONTDIR"

    if stringis_empty (osfontdir) then
        report ("info", 2, "db", "Scanning TEXMF fonts...")
    else
        report ("info", 2, "db", "Scanning TEXMF and OS fonts...")
        if logs.get_loglevel () > 3 then
            local osdirs = filesplitpath (osfontdir)
            report ("info", 0, "db",
                    "$OSFONTDIR has %d entries:", #osdirs)
            for i = 1, #osdirs do
                report ("info", 0, "db", "[%d] %s", i, osdirs[i])
            end
        end
    end

    fontdirs = kpseexpand_path "$OPENTYPEFONTS"
    fontdirs = fontdirs .. path_separator .. kpseexpand_path "$TTFONTS"
    fontdirs = fontdirs .. path_separator .. kpseexpand_path "$T1FONTS"

    if not stringis_empty (fontdirs) then
        local tasks = filter_out_pwd (filesplitpath (fontdirs))
        report ("info", 3, "db",
                "Initiating scan of %d directories.", #tasks)
        for _, d in next, tasks do
            local found, new = scan_dir (d, currentnames, targetnames,
                                         dry_run, "texmf")
            n_scanned = n_scanned + found
            n_new     = n_new     + new
        end
    end

    return n_scanned, n_new
end

--[[
  For the OS fonts, there are several options:
   - if OSFONTDIR is set (which is the case under windows by default but
     not on the other OSs), it scans it at the same time as the texmf tree,
     in the scan_texmf_fonts.
   - if not:
     - under Windows and Mac OSX, we take a look at some hardcoded directories
     - under Unix, we read /etc/fonts/fonts.conf and read the directories in it

  This means that if you have fonts in fancy directories, you need to set them
  in OSFONTDIR.
]]

local read_fonts_conf
do --- closure for read_fonts_conf()

    local alpha             = R("az", "AZ")
    local digit             = R"09"
    local tag_name          = C(alpha^1)
    local whitespace        = S" \n\r\t\v"
    local ws                = whitespace^1
    local comment           = P"<!--" * (1 - P"--")^0 * P"-->"

    ---> header specifica
    local xml_declaration   = P"<?xml" * (1 - P"?>")^0 * P"?>"
    local xml_doctype       = P"<!DOCTYPE" * ws
                            * "fontconfig" * (1 - P">")^0 * P">"
    local header            = xml_declaration^-1
                            * (xml_doctype + comment + ws)^0

    ---> enforce root node
    local root_start        = P"<"  * ws^-1 * P"fontconfig" * ws^-1 * P">"
    local root_stop         = P"</" * ws^-1 * P"fontconfig" * ws^-1 * P">"

    local dquote, squote    = P[["]], P"'"
    local xml_namestartchar = S":_" + alpha --- ascii only, funk the rest
    local xml_namechar      = S":._" + alpha + digit
    local xml_name          = ws^-1
                            * C(xml_namestartchar * xml_namechar^0)
    local xml_attvalue      = dquote * C((1 - S[[%&"]])^1) * dquote * ws^-1
                            + squote * C((1 - S[[%&']])^1) * squote * ws^-1
    local xml_attr          = Cg(xml_name * P"=" * xml_attvalue)
    local xml_attr_list     = Cf(Ct"" * xml_attr^1, rawset)

    --[[doc--
         scan_node creates a parser for a given xml tag.
    --doc]]--
    --- string -> bool -> lpeg_t
    local scan_node = function (tag)
        --- Node attributes go into a table with the index “attributes”
        --- (relevant for “prefix="xdg"” and the likes).
        local p_tag = P(tag)
        local with_attributes   = P"<" * p_tag
                                * Cg(xml_attr_list, "attributes")^-1
                                * ws^-1
                                * P">"
        local plain             = P"<" * p_tag * ws^-1 * P">"
        local node_start        = plain + with_attributes
        local node_stop         = P"</" * p_tag * ws^-1 * P">"
        --- there is no nesting, the earth is flat ...
        local node              = node_start
                                * Cc(tag) * C(comment + (1 - node_stop)^1)
                                * node_stop
        return Ct(node) -- returns {string, string [, attributes = { key = val }] }
    end

    --[[doc--
         At the moment, the interesting tags are “dir” for
         directory declarations, and “include” for including
         further configuration files.

         spec: http://freedesktop.org/software/fontconfig/fontconfig-user.html
    --doc]]--
    local include_node        = scan_node"include"
    local dir_node            = scan_node"dir"

    local element             = dir_node
                              + include_node
                              + comment         --> ignore
                              + P(1-root_stop)  --> skip byte

    local root                = root_start * Ct(element^0) * root_stop
    local p_cheapxml          = header * root

    --lpeg.print(p_cheapxml) ---> 757 rules with v0.10

    --[[doc--
         fonts_conf_scanner() handles configuration files.
         It is called on an abolute path to a config file (e.g.
         /home/luser/.config/fontconfig/fonts.conf) and returns a list
         of the nodes it managed to extract from the file.
    --doc]]--
    --- string -> path list
    local fonts_conf_scanner = function (path)
        local fh = ioopen(path, "r")
        if not fh then
            report("both", 3, "db", "Cannot open fontconfig file %s", path)
            return
        end
        local raw = fh:read"*all"
        fh:close()

        local confdata = lpegmatch(p_cheapxml, raw)
        if not confdata then
            report("both", 3, "db", "Cannot scan fontconfig file %s", path)
            return
        end
        return confdata
    end

    local p_conf   = P".conf" * P(-1)
    local p_filter = (1 - p_conf)^1 * p_conf

    local conf_filter = function (path)
        if lpegmatch (p_filter, path) then
            return true
        end
        return false
    end

    --[[doc--
         read_fonts_conf_indeed() is called with six arguments; the
         latter three are tables that represent the state and are
         always returned.
         The first three are
             · the path to the file
             · the expanded $HOME
             · the expanded $XDG_CONFIG_DIR
    --doc]]--
    --- string -> string -> string -> tab -> tab -> (tab * tab * tab)
    local read_fonts_conf_indeed
    read_fonts_conf_indeed = function (start, home, xdg_home,
                                       acc, done, dirs_done)

        local paths = fonts_conf_scanner(start)
        if not paths then --- nothing to do
            return acc, done, dirs_done
        end

        for i=1, #paths do
            local pathobj = paths[i]
            local kind, path = pathobj[1], pathobj[2]
            local attributes = pathobj.attributes
            if attributes and attributes.prefix == "xdg" then
                --- this prepends the xdg root (usually ~/.config)
                path = filejoin(xdg_home, path)
            end

            if kind == "dir" then
                if stringsub(path, 1, 1) == "~" then
                    path = filejoin(home, stringsub(path, 2))
                end
                --- We exclude paths with texmf in them, as they should be
                --- found anyway; also duplicates are ignored by checking
                --- if they are elements of dirs_done.
                ---
                --- FIXME does this mean we cannot access paths from
                --- distributions (e.g. Context minimals) installed
                --- separately?
                if not (stringfind(path, "texmf") or dirs_done[path]) then
                    acc[#acc+1] = path
                    dirs_done[path] = true
                end

            elseif kind == "include" then
                --- here the path can be four things: a directory or a file,
                --- in absolute or relative path.
                if stringsub(path, 1, 1) == "~" then
                    path = filejoin(home, stringsub(path, 2))
                elseif --- if the path is relative, we make it absolute
                    not ( lfsisfile(path) or lfsisdir(path) )
                then
                    path = filejoin(filedirname(start), path)
                end
                if  lfsisfile(path)
                    and kpsereadable_file(path)
                    and not done[path]
                then
                    --- we exclude path with texmf in them, as they should
                    --- be found otherwise
                    acc = read_fonts_conf_indeed(
                                path, home, xdg_home,
                                acc,  done, dirs_done)
                elseif lfsisdir(path) then --- arrow code ahead
                    local config_files = find_files (path, conf_filter)
                    for _, filename in next, config_files do
                        if not done[filename] then
                            acc = read_fonts_conf_indeed(
                            filename, home, xdg_home,
                            acc,      done, dirs_done)
                        end
                    end
                end --- match “kind”
            end --- iterate paths
        end

        --inspect(acc)
        --inspect(done)
        return acc, done, dirs_done
    end --- read_fonts_conf_indeed()

    --[[doc--
         read_fonts_conf() sets up an accumulator and two sets
         for tracking what’s been done.

         Also, the environment variables HOME and XDG_CONFIG_HOME --
         which are constants anyways -- are expanded so don’t have to
         repeat that over and over again as with the old parser.
         Now they’re just passed on to every call of
         read_fonts_conf_indeed().

         read_fonts_conf() is also the only reference visible outside
         the closure.
    --doc]]--
    --- list -> list
    read_fonts_conf = function (path_list)
        local home      = kpseexpand_path"~" --- could be os.getenv"HOME"
        local xdg_home  = kpseexpand_path"$XDG_CONFIG_HOME"
        if xdg_home == "" then xdg_home = filejoin(home, ".config") end
        local acc       = { } ---> list: paths collected
        local done      = { } ---> set:  files inspected
        local dirs_done = { } ---> set:  dirs in list
        for i=1, #path_list do --- we keep the state between files
            acc, done, dirs_done = read_fonts_conf_indeed(
                                     path_list[i], home, xdg_home,
                                     acc, done, dirs_done)
        end
        return acc
    end
end --- read_fonts_conf closure

--- TODO stuff those paths into some writable table
--- unit -> string list
local function get_os_dirs ()
    if os.name == 'macosx' then
        return {
            filejoin(kpseexpand_path('~'), "Library/Fonts"),
            "/Library/Fonts",
            "/System/Library/Fonts",
            "/Network/Library/Fonts",
        }
    elseif os.type == "windows" or os.type == "msdos" then
        local windir = os.getenv("WINDIR")
        return { filejoin(windir, 'Fonts') }
    else
        local fonts_conves = { --- plural, much?
            "/usr/local/etc/fonts/fonts.conf",
            "/etc/fonts/fonts.conf",
        }
        local os_dirs = read_fonts_conf(fonts_conves)
        return os_dirs
    end
    return {}
end

--[[doc--

    scan_os_fonts() scans the OS fonts through
      - fontconfig for Unix (reads the fonts.conf file[s] and scans the
        directories)
      - a static set of directories for Windows and MacOSX

    **NB**: If $OSFONTDIR is nonempty, as it appears to be by default
            on Windows setups, the system fonts will have already been
            processed while scanning the TEXMF. Thus, this function is
            never called.

--doc]]--

--- dbobj -> dbobj -> bool? -> (int * int)
local scan_os_fonts = function (currentnames,
                                targetnames,
                                dry_run)

    local n_scanned, n_new = 0, 0
    report ("info", 2, "db", "Scanning OS fonts...")
    report ("info", 3, "db",
            "Searching in static system directories...")

    for _, d in next, get_os_dirs () do
        local found, new = scan_dir (d, currentnames,
                                     targetnames, dry_run)
        n_scanned = n_scanned + found
        n_new     = n_new     + new
    end

    return n_scanned, n_new
end

--- unit -> (bool, lookup_cache)
flush_lookup_cache = function ()
    if not names.lookups then names.lookups = load_lookups() end
    names.lookups = { }
    collectgarbage "collect"
    return true, names.lookups
end


--- fontentry list -> filemap

local generate_filedata = function (mappings)

    report ("both", 2, "db", "Creating filename map")

    local nmappings  = #mappings

    local filenames  = {
        bare = {
            ["local"]   = { },
            system      = { }, --- mapped to mapping format -> index in full
            texmf       = { }, --- mapped to mapping format -> “true”
        },
        base = {
            ["local"]   = { },
            system      = { }, --- mapped to index in “full”
            texmf       = { }, --- set; all values are “true”
        },
        full = { }, --- non-texmf
    }

    local base = filenames.base
    local bare = filenames.bare
    local full = filenames.full

    local conflicts = {
        basenames = 0,
        barenames = 0,
    }

    for index = 1, nmappings do
        local entry    = mappings [index]

        local filedata = entry.file

        local format   = entry.format   --- otf, afm, ...
        local location = filedata.location --- texmf, system, ...

        local fullname = filedata.full
        local basename = filedata.base
        local barename = filenameonly (fullname)
        local subfont  = filedata.subfont

        entry.index    = index

        --- 1) add to basename table

        local inbase = base [location] --- no format since the suffix is known

        if inbase then
            local present = inbase [basename]
            if present then
                report ("both", 4, "db",
                        "Conflicting basename: %q already indexed \z
                         in category %s, ignoring.",
                        barename, location)
                conflicts.basenames = conflicts.basenames + 1

                --- track conflicts per font
                local conflictdata = entry.conflicts

                if not conflictdata then
                    entry.conflicts = { basename = present }
                else -- some conflicts already detected
                    conflictdata.basename = present
                end

            else
                inbase [basename] = index
            end
        else
            inbase = { basename = index }
            base [location] = inbase
        end

        --- 2) add to barename table

        local inbare = bare [location] [format]

        if inbare then
            local present = inbare [barename]
            if present then
                report ("both", 4, "db",
                        "Conflicting barename: %q already indexed \z
                         in category %s/%s, ignoring.",
                        barename, location, format)
                conflicts.barenames = conflicts.barenames + 1

                --- track conflicts per font
                local conflictdata = entry.conflicts

                if not conflictdata then
                    entry.conflicts = { barename = present }
                else -- some conflicts already detected
                    conflictdata.barename = present
                end

            else
                inbare [barename] = index
            end
        else
            inbare = { barename = index }
            bare [location] [format] = inbare
        end

        --- 3) add to fullname map

        full [index] = fullname
    end

    --- TODO adapt to new mechanism!
--    if config.luaotfload.prioritize == "texmf" then
--        report("both", 2, "db", "Preferring texmf fonts")
--        addmap(sys)
--        addmap(texmf)
--    else --- sys
--        addmap(texmf)
--        addmap(sys)
--    end

    return filenames
end


local retrieve_namedata = function (currentnames,
                                    targetnames,
                                    dry_run,
                                    n_rawnames,
                                    n_newnames)
    local rawnames, new = scan_texmf_fonts (currentnames,
                                            targetnames,
                                            dry_run)

    n_rawnames    = n_rawnames + rawnames
    n_newnames    = n_newnames + new

    rawnames, new = scan_os_fonts (currentnames, targetnames, dry_run)

    n_rawnames    = n_rawnames + rawnames
    n_newnames    = n_newnames + new

    return n_rawnames, n_newnames
end


--- dbobj -> stats

local collect_statistics = function (mappings)
    local sum_dsnsize, n_dsnsize = 0, 0

    local fullname, family, families = { }, { }, { }
    local subfamily, prefmodifiers, fontstyle_name = { }, { }, { }

    local addtohash = function (hash, item)
        if item then
            local times = hash [item]
            if times then
                hash [item] = times + 1
            else
                hash [item] = 1
            end
        end
    end

    local appendtohash = function (hash, key, value)
        if key and value then
            local entry = hash [key]
            if entry then
                entry [#entry + 1] = value
            else
                hash [key] = { value }
            end
        end
    end

    local addtoset = function (hash, key, value)
        if key and value then
            local set = hash [key]
            if set then
                set [value] = true
            else
                hash [key] = { [value] = true }
            end
        end
    end

    local setsize = function (set)
        local n = 0
        for _, _ in next, set do
            n = n + 1
        end
        return n
    end

    local hashsum = function (hash)
        local n = 0
        for _, m in next, hash do
            n = n + m
        end
        return n
    end

    for _, entry in next, mappings do
        local style        = entry.style
        local names        = entry.names.sanitized
        local englishnames = names.english

        addtohash (fullname,        englishnames.fullname)
        addtohash (family,          englishnames.family)
        addtohash (subfamily,       englishnames.subfamily)
        addtohash (prefmodifiers,   englishnames.prefmodifiers)
        addtohash (fontstyle_name,  names.fontstyle_name)

        addtoset (families, englishnames.family, englishnames.fullname)

        local sizeinfo = entry.style.size
        if sizeinfo then
            sum_dsnsize = sum_dsnsize + sizeinfo [1]
            n_dsnsize = n_dsnsize + 1
        end
    end

    --inspect (families)

    local n_fullname = setsize (fullname)
    local n_family   = setsize (family)

    if logs.get_loglevel () > 1 then
        local pprint_top = function (hash, n, set)

            local freqs = { }
            local items = { }

            for item, value in next, hash do
                if set then
                    freq = setsize (value)
                else
                    freq = value
                end
                local ifreq = items [freq]
                if ifreq then
                    ifreq [#ifreq + 1] = item
                else
                    items [freq] = { item }
                    freqs [#freqs + 1] = freq
                end
            end

            tablesort (freqs)

            local from = #freqs
            local to   = from - (n - 1)
            if to < 1 then
                to = 1
            end

            for i = from, to, -1 do
                local freq     = freqs [i]
                local itemlist = items [freq]

                if type (itemlist) == "table" then
                    itemlist = tableconcat (itemlist, ", ")
                end

                report ("both", 0, "db",
                        "       · %4d × %s.",
                        freq, itemlist)
            end
        end

        report ("both", 0, "", "~~~~ font index statistics ~~~~")
        report ("both", 0, "db",
                "   · Collected %d fonts (%d names) in %d families.",
                #mappings, n_fullname, n_family)
        pprint_top (families, 4, true)

        report ("both", 0, "db",
                "   · %d different “subfamily” kinds",
                setsize (subfamily))
        pprint_top (subfamily, 4)

        report ("both", 0, "db",
                "   · %d different “prefmodifiers” kinds",
                setsize (prefmodifiers))
        pprint_top (prefmodifiers, 4)

        report ("both", 0, "db",
                "   · %d different “fontstyle_name” kinds",
                setsize (fontstyle_name))
        pprint_top (fontstyle_name, 4)
    end

    local mean_dsnsize = 0
    if n_dsnsize > 0 then
        mean_dsnsize = sum_dsnsize / n_dsnsize
    end

    return {
        mean_dsnsize = mean_dsnsize,
        names = {
            fullname = n_fullname,
            families = n_family,
        },
--        style = {
--            subfamily = subfamily,
--            prefmodifiers = prefmodifiers,
--            fontstyle_name = fontstyle_name,
--        },
    }
end

--- force:      dictate rebuild from scratch
--- dry_dun:    don’t write to the db, just scan dirs

--- dbobj? -> bool? -> bool? -> dbobj
update_names = function (currentnames, force, dry_run)

    if config.luaotfload.update_live == false then
        report ("info", 2, "db",
                "Skipping database update")
        --- skip all db updates
        return currentnames or names.data
    end

    local starttime                 = osgettimeofday ()
    local n_rawnames, n_newnames    = 0, 0

    --[[
    The main function, scans everything
    - “targetnames” is the final table to return
    - force is whether we rebuild it from scratch or not
    ]]
    report ("both", 2, "db", "Updating the font names database"
                          .. (force and " forcefully" or ""))

    if force then
        currentnames = initialize_namedata (get_font_filter ())
    else
        if not currentnames then
            currentnames = load_names (dry_run)
        end
        if currentnames.meta.version ~= names.version then
            report ("both", 1, "db", "No font names database or old "
                                  .. "one found; generating new one")
            currentnames = initialize_namedata (get_font_filter ())
        end
    end

    local targetnames = initialize_namedata (get_font_filter ())

    read_blacklist ()

    local n_rawnames, n_newnames = retrieve_namedata (currentnames,
                                                      targetnames,
                                                      dry_run,
                                                      n_rawnames,
                                                      n_newnames)
    targetnames.meta.statistics = collect_statistics (targetnames.mappings)

    --- we always generate the file lookup tables because
    --- non-texmf entries are redirected there and the mapping
    --- needs to be 100% consistent

    targetnames.files = generate_filedata (targetnames.mappings)

    --- stats:
    ---            before rewrite   | after rewrite
    ---   partial:         804 ms   |   701 ms
    ---   forced:        45384 ms   | 44714 ms
    report ("info", 3, "db",
            "Scanned %d font files; %d new entries.",
            n_rawnames, n_newnames)
    report ("info", 3, "db",
            "Rebuilt in %0.f ms.",
            1000 * (osgettimeofday () - starttime))
    names.data = targetnames

    if dry_run ~= true then

        save_names ()

        local success, _lookups = flush_lookup_cache ()
        if success then
            local success = names.save_lookups ()
            if success then
                logs.names_report ("info", 2, "cache",
                                   "Lookup cache emptied")
                return targetnames
            end
        end
    end
    return targetnames
end

--- unit -> bool
save_lookups = function ( )
    local lookups = names.lookups
    local path    = names.path.lookups
    local luaname, lucname = path.lua, path.luc
    if fileiswritable (luaname) and fileiswritable (lucname) then
        tabletofile (luaname, lookups, true)
        osremove (lucname)
        caches.compile (lookups, luaname, lucname)
        --- double check ...
        if lfsisfile (luaname) and lfsisfile (lucname) then
            report ("both", 3, "cache", "Lookup cache saved")
            return true
        end
        report ("info", 0, "cache", "Could not compile lookup cache")
        return false
    end
    report ("info", 0, "cache", "Lookup cache file not writable")
    if not fileiswritable (luaname) then
        report ("info", 0, "cache", "Failed to write %s", luaname)
    end
    if not fileiswritable (lucname) then
        report ("info", 0, "cache", "Failed to write %s", lucname)
    end
    return false
end

--- save_names() is usually called without the argument
--- dbobj? -> bool
save_names = function (currentnames)
    if not currentnames then
        currentnames = names.data
    end
    local path = names.path.index
    local luaname, lucname = path.lua, path.luc
    if fileiswritable (luaname) and fileiswritable (lucname) then
        tabletofile (luaname, currentnames, true)
        osremove (lucname)
        caches.compile (currentnames, luaname, lucname)
        if lfsisfile (luaname) and lfsisfile (lucname) then
            report ("info", 1, "db", "Font index saved")
            report ("info", 3, "db", "Text: " .. luaname)
            report ("info", 3, "db", "Byte: " .. lucname)
            return true
        end
        report ("info", 0, "db", "Could not compile font index")
        return false
    end
    report ("info", 0, "db", "Index file not writable")
    if not fileiswritable (luaname) then
        report ("info", 0, "db", "Failed to write %s", luaname)
    end
    if not fileiswritable (lucname) then
        report ("info", 0, "db", "Failed to write %s", lucname)
    end
    return false
end

--[[doc--

    Below set of functions is modeled after mtx-cache.

--doc]]--

--- string -> string -> string list -> string list -> string list -> unit
local print_cache = function (category, path, luanames, lucnames, rest)
    local report_indeed = function (...)
        report("info", 0, "cache", ...)
    end
    report_indeed("Luaotfload cache: %s", category)
    report_indeed("location: %s", path)
    report_indeed("[raw]       %4i", #luanames)
    report_indeed("[compiled]  %4i", #lucnames)
    report_indeed("[other]     %4i", #rest)
    report_indeed("[total]     %4i", #luanames + #lucnames + #rest)
end

--- string -> string -> string list -> bool -> bool
local purge_from_cache = function (category, path, list, all)
    report("info", 2, "cache", "Luaotfload cache: %s %s",
        (all and "erase" or "purge"), category)
    report("info", 2, "cache", "location: %s",path)
    local n = 0
    for i=1,#list do
        local filename = list[i]
        if stringfind(filename,"luatex%-cache") then -- safeguard
            if all then
                report("info", 5, "cache", "removing %s", filename)
                osremove(filename)
                n = n + 1
            else
                local suffix = filesuffix(filename)
                if suffix == "lua" then
                    local checkname = file.replacesuffix(
                        filename, "lua", "luc")
                    if lfsisfile(checkname) then
                        report("info", 5, "cache", "Removing %s", filename)
                        osremove(filename)
                        n = n + 1
                    end
                end
            end
        end
    end
    report("info", 2, "cache", "Removed lua files : %i", n)
    return true
end

--- string -> string list -> int -> string list -> string list -> string list ->
---     (string list * string list * string list * string list)
local collect_cache collect_cache = function (path, all, n, luanames,
                                              lucnames, rest)
    if not all then
        local all = find_files (path)

        local luanames, lucnames, rest = { }, { }, { }
        return collect_cache(nil, all, 1, luanames, lucnames, rest)
    end

    local filename = all[n]
    if filename then
        local suffix = filesuffix(filename)
        if suffix == "lua" then
            luanames[#luanames+1] = filename
        elseif suffix == "luc" then
            lucnames[#lucnames+1] = filename
        else
            rest[#rest+1] = filename
        end
        return collect_cache(nil, all, n+1, luanames, lucnames, rest)
    end
    return luanames, lucnames, rest, all
end

local getwritablecachepath = function ( )
    --- fonts.handlers.otf doesn’t exist outside a Luatex run,
    --- so we have to improvise
    local writable = getwritablepath (config.luaotfload.cache_dir)
    if writable then
        return writable
    end
end

local getreadablecachepaths = function ( )
    local readables = caches.getreadablepaths
                        (config.luaotfload.cache_dir)
    local result    = { }
    if readables then
        for i=1, #readables do
            local readable = readables[i]
            if lfsisdir (readable) then
                result[#result+1] = readable
            end
        end
    end
    return result
end

--- unit -> unit
local purge_cache = function ( )
    local writable_path = getwritablecachepath ()
    local luanames, lucnames, rest = collect_cache(writable_path)
    if logs.get_loglevel() > 1 then
        print_cache("writable path", writable_path, luanames, lucnames, rest)
    end
    local success = purge_from_cache("writable path", writable_path, luanames, false)
    return success
end

--- unit -> unit
local erase_cache = function ( )
    local writable_path = getwritablecachepath ()
    local luanames, lucnames, rest, all = collect_cache(writable_path)
    if logs.get_loglevel() > 1 then
        print_cache("writable path", writable_path, luanames, lucnames, rest)
    end
    local success = purge_from_cache("writable path", writable_path, all, true)
    return success
end

local separator = function ( )
    report("info", 0, string.rep("-", 67))
end

--- unit -> unit
local show_cache = function ( )
    local readable_paths = getreadablecachepaths ()
    local writable_path  = getwritablecachepath ()
    local luanames, lucnames, rest = collect_cache(writable_path)

    separator ()
    print_cache ("writable path", writable_path,
                 luanames, lucnames, rest)
    texiowrite_nl""
    for i=1,#readable_paths do
        local readable_path = readable_paths[i]
        if readable_path ~= writable_path then
            local luanames, lucnames = collect_cache (readable_path)
            print_cache ("readable path",
                         readable_path, luanames, lucnames, rest)
        end
    end
    separator()
    return true
end

-----------------------------------------------------------------------
--- export functionality to the namespace “fonts.names”
-----------------------------------------------------------------------

names.scan_dir                    = scan_dir
names.set_font_filter             = set_font_filter
names.flush_lookup_cache          = flush_lookup_cache
names.save_lookups                = save_lookups
names.load                        = load_names
names.save                        = save_names
names.update                      = update_names
names.crude_file_lookup           = crude_file_lookup
names.crude_file_lookup_verbose   = crude_file_lookup_verbose
names.read_blacklist              = read_blacklist
names.sanitize_fontname           = sanitize_fontname
names.getfilename                 = resolve_fullpath

--- font cache
names.purge_cache    = purge_cache
names.erase_cache    = erase_cache
names.show_cache     = show_cache

--- replace the resolver from luatex-fonts
if config.luaotfload.resolver == "cached" then
    report("both", 2, "cache", "caching of name: lookups active")
    names.resolve     = resolve_cached
    names.resolvespec = resolve_cached
else
    names.resolve     = resolve
    names.resolvespec = resolve
end

names.find_closest = find_closest

-- for testing purpose
names.read_fonts_conf = read_fonts_conf

-- vim:tw=71:sw=4:ts=4:expandtab