aboutsummaryrefslogtreecommitdiffhomepage
path: root/src/ports/SkFontMgr_fontconfig.cpp
blob: be4b17dd12f9ff6ae960717221c8257df0835574 (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
/*
 * Copyright 2014 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#include "SkAdvancedTypefaceMetrics.h"
#include "SkDataTable.h"
#include "SkFixed.h"
#include "SkFontDescriptor.h"
#include "SkFontHost_FreeType_common.h"
#include "SkFontMgr.h"
#include "SkFontStyle.h"
#include "SkMakeUnique.h"
#include "SkMath.h"
#include "SkMutex.h"
#include "SkOSFile.h"
#include "SkRefCnt.h"
#include "SkStream.h"
#include "SkString.h"
#include "SkTDArray.h"
#include "SkTemplates.h"
#include "SkTypeface.h"
#include "SkTypefaceCache.h"
#include "SkTypes.h"

#include <fontconfig/fontconfig.h>
#include <string.h>

class SkData;

// FC_POSTSCRIPT_NAME was added with b561ff20 which ended up in 2.10.92
// Ubuntu 12.04 is on 2.8.0, 13.10 is on 2.10.93
// Debian 7 is on 2.9.0, 8 is on 2.11
// OpenSUSE 12.2 is on 2.9.0, 12.3 is on 2.10.2, 13.1 2.11.0
// Fedora 19 is on 2.10.93
#ifndef FC_POSTSCRIPT_NAME
#    define FC_POSTSCRIPT_NAME  "postscriptname"
#endif

#ifdef SK_DEBUG
#    include "SkTLS.h"
#endif

/** Since FontConfig is poorly documented, this gives a high level overview:
 *
 *  FcConfig is a handle to a FontConfig configuration instance. Each 'configuration' is independent
 *  from any others which may exist. There exists a default global configuration which is created
 *  and destroyed by FcInit and FcFini, but this default should not normally be used.
 *  Instead, one should use FcConfigCreate and FcInit* to have a named local state.
 *
 *  FcPatterns are {objectName -> [element]} (maps from object names to a list of elements).
 *  Each element is some internal data plus an FcValue which is a variant (a union with a type tag).
 *  Lists of elements are not typed, except by convention. Any collection of FcValues must be
 *  assumed to be heterogeneous by the code, but the code need not do anything particularly
 *  interesting if the values go against convention.
 *
 *  Somewhat like DirectWrite, FontConfig supports synthetics through FC_EMBOLDEN and FC_MATRIX.
 *  Like all synthetic information, such information must be passed with the font data.
 */

namespace {

// Fontconfig is not threadsafe before 2.10.91. Before that, we lock with a global mutex.
// See https://bug.skia.org/1497 for background.
SK_DECLARE_STATIC_MUTEX(gFCMutex);

#ifdef SK_DEBUG
void* CreateThreadFcLocked() { return new bool(false); }
void DeleteThreadFcLocked(void* v) { delete static_cast<bool*>(v); }
#   define THREAD_FC_LOCKED \
        static_cast<bool*>(SkTLS::Get(CreateThreadFcLocked, DeleteThreadFcLocked))
#endif

struct FCLocker {
    // Assume FcGetVersion() has always been thread safe.

    FCLocker() {
        if (FcGetVersion() < 21091) {
            gFCMutex.acquire();
        } else {
            SkDEBUGCODE(bool* threadLocked = THREAD_FC_LOCKED);
            SkASSERT(false == *threadLocked);
            SkDEBUGCODE(*threadLocked = true);
        }
    }

    ~FCLocker() {
        AssertHeld();
        if (FcGetVersion() < 21091) {
            gFCMutex.release();
        } else {
            SkDEBUGCODE(*THREAD_FC_LOCKED = false);
        }
    }

    static void AssertHeld() { SkDEBUGCODE(
        if (FcGetVersion() < 21091) {
            gFCMutex.assertHeld();
        } else {
            SkASSERT(true == *THREAD_FC_LOCKED);
        }
    ) }
};

} // namespace

template<typename T, void (*D)(T*)> void FcTDestroy(T* t) {
    FCLocker::AssertHeld();
    D(t);
}
template <typename T, T* (*C)(), void (*D)(T*)> class SkAutoFc
    : public SkAutoTCallVProc<T, FcTDestroy<T, D> > {
public:
    SkAutoFc() : SkAutoTCallVProc<T, FcTDestroy<T, D> >(C()) {
        T* obj = this->operator T*();
        SkASSERT_RELEASE(nullptr != obj);
    }
    explicit SkAutoFc(T* obj) : SkAutoTCallVProc<T, FcTDestroy<T, D> >(obj) {}
};

typedef SkAutoFc<FcCharSet, FcCharSetCreate, FcCharSetDestroy> SkAutoFcCharSet;
typedef SkAutoFc<FcConfig, FcConfigCreate, FcConfigDestroy> SkAutoFcConfig;
typedef SkAutoFc<FcFontSet, FcFontSetCreate, FcFontSetDestroy> SkAutoFcFontSet;
typedef SkAutoFc<FcLangSet, FcLangSetCreate, FcLangSetDestroy> SkAutoFcLangSet;
typedef SkAutoFc<FcObjectSet, FcObjectSetCreate, FcObjectSetDestroy> SkAutoFcObjectSet;
typedef SkAutoFc<FcPattern, FcPatternCreate, FcPatternDestroy> SkAutoFcPattern;

static bool get_bool(FcPattern* pattern, const char object[], bool missing = false) {
    FcBool value;
    if (FcPatternGetBool(pattern, object, 0, &value) != FcResultMatch) {
        return missing;
    }
    return value;
}

static int get_int(FcPattern* pattern, const char object[], int missing) {
    int value;
    if (FcPatternGetInteger(pattern, object, 0, &value) != FcResultMatch) {
        return missing;
    }
    return value;
}

static const char* get_string(FcPattern* pattern, const char object[], const char* missing = "") {
    FcChar8* value;
    if (FcPatternGetString(pattern, object, 0, &value) != FcResultMatch) {
        return missing;
    }
    return (const char*)value;
}

static const FcMatrix* get_matrix(FcPattern* pattern, const char object[]) {
    FcMatrix* matrix;
    if (FcPatternGetMatrix(pattern, object, 0, &matrix) != FcResultMatch) {
        return nullptr;
    }
    return matrix;
}

enum SkWeakReturn {
    kIsWeak_WeakReturn,
    kIsStrong_WeakReturn,
    kNoId_WeakReturn
};
/** Ideally there  would exist a call like
 *  FcResult FcPatternIsWeak(pattern, object, id, FcBool* isWeak);
 *
 *  However, there is no such call and as of Fc 2.11.0 even FcPatternEquals ignores the weak bit.
 *  Currently, the only reliable way of finding the weak bit is by its effect on matching.
 *  The weak bit only affects the matching of FC_FAMILY and FC_POSTSCRIPT_NAME object values.
 *  A element with the weak bit is scored after FC_LANG, without the weak bit is scored before.
 *  Note that the weak bit is stored on the element, not on the value it holds.
 */
static SkWeakReturn is_weak(FcPattern* pattern, const char object[], int id) {
    FCLocker::AssertHeld();

    FcResult result;

    // Create a copy of the pattern with only the value 'pattern'['object'['id']] in it.
    // Internally, FontConfig pattern objects are linked lists, so faster to remove from head.
    SkAutoFcObjectSet requestedObjectOnly(FcObjectSetBuild(object, nullptr));
    SkAutoFcPattern minimal(FcPatternFilter(pattern, requestedObjectOnly));
    FcBool hasId = true;
    for (int i = 0; hasId && i < id; ++i) {
        hasId = FcPatternRemove(minimal, object, 0);
    }
    if (!hasId) {
        return kNoId_WeakReturn;
    }
    FcValue value;
    result = FcPatternGet(minimal, object, 0, &value);
    if (result != FcResultMatch) {
        return kNoId_WeakReturn;
    }
    while (hasId) {
        hasId = FcPatternRemove(minimal, object, 1);
    }

    // Create a font set with two patterns.
    // 1. the same 'object' as minimal and a lang object with only 'nomatchlang'.
    // 2. a different 'object' from minimal and a lang object with only 'matchlang'.
    SkAutoFcFontSet fontSet;

    SkAutoFcLangSet strongLangSet;
    FcLangSetAdd(strongLangSet, (const FcChar8*)"nomatchlang");
    SkAutoFcPattern strong(FcPatternDuplicate(minimal));
    FcPatternAddLangSet(strong, FC_LANG, strongLangSet);

    SkAutoFcLangSet weakLangSet;
    FcLangSetAdd(weakLangSet, (const FcChar8*)"matchlang");
    SkAutoFcPattern weak;
    FcPatternAddString(weak, object, (const FcChar8*)"nomatchstring");
    FcPatternAddLangSet(weak, FC_LANG, weakLangSet);

    FcFontSetAdd(fontSet, strong.release());
    FcFontSetAdd(fontSet, weak.release());

    // Add 'matchlang' to the copy of the pattern.
    FcPatternAddLangSet(minimal, FC_LANG, weakLangSet);

    // Run a match against the copy of the pattern.
    // If the 'id' was weak, then we should match the pattern with 'matchlang'.
    // If the 'id' was strong, then we should match the pattern with 'nomatchlang'.

    // Note that this config is only used for FcFontRenderPrepare, which we don't even want.
    // However, there appears to be no way to match/sort without it.
    SkAutoFcConfig config;
    FcFontSet* fontSets[1] = { fontSet };
    SkAutoFcPattern match(FcFontSetMatch(config, fontSets, SK_ARRAY_COUNT(fontSets),
                                         minimal, &result));

    FcLangSet* matchLangSet;
    FcPatternGetLangSet(match, FC_LANG, 0, &matchLangSet);
    return FcLangEqual == FcLangSetHasLang(matchLangSet, (const FcChar8*)"matchlang")
                        ? kIsWeak_WeakReturn : kIsStrong_WeakReturn;
}

/** Removes weak elements from either FC_FAMILY or FC_POSTSCRIPT_NAME objects in the property.
 *  This can be quite expensive, and should not be used more than once per font lookup.
 *  This removes all of the weak elements after the last strong element.
 */
static void remove_weak(FcPattern* pattern, const char object[]) {
    FCLocker::AssertHeld();

    SkAutoFcObjectSet requestedObjectOnly(FcObjectSetBuild(object, nullptr));
    SkAutoFcPattern minimal(FcPatternFilter(pattern, requestedObjectOnly));

    int lastStrongId = -1;
    int numIds;
    SkWeakReturn result;
    for (int id = 0; ; ++id) {
        result = is_weak(minimal, object, 0);
        if (kNoId_WeakReturn == result) {
            numIds = id;
            break;
        }
        if (kIsStrong_WeakReturn == result) {
            lastStrongId = id;
        }
        SkAssertResult(FcPatternRemove(minimal, object, 0));
    }

    // If they were all weak, then leave the pattern alone.
    if (lastStrongId < 0) {
        return;
    }

    // Remove everything after the last strong.
    for (int id = lastStrongId + 1; id < numIds; ++id) {
        SkAssertResult(FcPatternRemove(pattern, object, lastStrongId + 1));
    }
}

static int map_range(SkFixed value,
                     SkFixed old_min, SkFixed old_max,
                     SkFixed new_min, SkFixed new_max)
{
    SkASSERT(old_min < old_max);
    SkASSERT(new_min <= new_max);
    return new_min + SkMulDiv(value - old_min, new_max - new_min, old_max - old_min);
}

struct MapRanges {
    SkFixed old_val;
    SkFixed new_val;
};

static SkFixed map_ranges_fixed(SkFixed val, MapRanges const ranges[], int rangesCount) {
    // -Inf to [0]
    if (val < ranges[0].old_val) {
        return ranges[0].new_val;
    }

    // Linear from [i] to [i+1]
    for (int i = 0; i < rangesCount - 1; ++i) {
        if (val < ranges[i+1].old_val) {
            return map_range(val, ranges[i].old_val, ranges[i+1].old_val,
                                  ranges[i].new_val, ranges[i+1].new_val);
        }
    }

    // From [n] to +Inf
    // if (fcweight < Inf)
    return ranges[rangesCount-1].new_val;
}

static int map_ranges(int val, MapRanges const ranges[], int rangesCount) {
    return SkFixedRoundToInt(map_ranges_fixed(SkIntToFixed(val), ranges, rangesCount));
}

template<int n> struct SkTFixed {
    static_assert(-32768 <= n && n <= 32767, "SkTFixed_n_not_in_range");
    static const SkFixed value = static_cast<SkFixed>(n << 16);
};

static SkFontStyle skfontstyle_from_fcpattern(FcPattern* pattern) {
    typedef SkFontStyle SkFS;

    static const MapRanges weightRanges[] = {
        { SkTFixed<FC_WEIGHT_THIN>::value,       SkTFixed<SkFS::kThin_Weight>::value },
        { SkTFixed<FC_WEIGHT_EXTRALIGHT>::value, SkTFixed<SkFS::kExtraLight_Weight>::value },
        { SkTFixed<FC_WEIGHT_LIGHT>::value,      SkTFixed<SkFS::kLight_Weight>::value },
        { SkTFixed<FC_WEIGHT_REGULAR>::value,    SkTFixed<SkFS::kNormal_Weight>::value },
        { SkTFixed<FC_WEIGHT_MEDIUM>::value,     SkTFixed<SkFS::kMedium_Weight>::value },
        { SkTFixed<FC_WEIGHT_DEMIBOLD>::value,   SkTFixed<SkFS::kSemiBold_Weight>::value },
        { SkTFixed<FC_WEIGHT_BOLD>::value,       SkTFixed<SkFS::kBold_Weight>::value },
        { SkTFixed<FC_WEIGHT_EXTRABOLD>::value,  SkTFixed<SkFS::kExtraBold_Weight>::value },
        { SkTFixed<FC_WEIGHT_BLACK>::value,      SkTFixed<SkFS::kBlack_Weight>::value },
        { SkTFixed<FC_WEIGHT_EXTRABLACK>::value, SkTFixed<SkFS::kExtraBlack_Weight>::value },
    };
    int weight = map_ranges(get_int(pattern, FC_WEIGHT, FC_WEIGHT_REGULAR),
                            weightRanges, SK_ARRAY_COUNT(weightRanges));

    static const MapRanges widthRanges[] = {
        { SkTFixed<FC_WIDTH_ULTRACONDENSED>::value, SkTFixed<SkFS::kUltraCondensed_Width>::value },
        { SkTFixed<FC_WIDTH_EXTRACONDENSED>::value, SkTFixed<SkFS::kExtraCondensed_Width>::value },
        { SkTFixed<FC_WIDTH_CONDENSED>::value,      SkTFixed<SkFS::kCondensed_Width>::value },
        { SkTFixed<FC_WIDTH_SEMICONDENSED>::value,  SkTFixed<SkFS::kSemiCondensed_Width>::value },
        { SkTFixed<FC_WIDTH_NORMAL>::value,         SkTFixed<SkFS::kNormal_Width>::value },
        { SkTFixed<FC_WIDTH_SEMIEXPANDED>::value,   SkTFixed<SkFS::kSemiExpanded_Width>::value },
        { SkTFixed<FC_WIDTH_EXPANDED>::value,       SkTFixed<SkFS::kExpanded_Width>::value },
        { SkTFixed<FC_WIDTH_EXTRAEXPANDED>::value,  SkTFixed<SkFS::kExtraExpanded_Width>::value },
        { SkTFixed<FC_WIDTH_ULTRAEXPANDED>::value,  SkTFixed<SkFS::kUltraExpanded_Width>::value },
    };
    int width = map_ranges(get_int(pattern, FC_WIDTH, FC_WIDTH_NORMAL),
                           widthRanges, SK_ARRAY_COUNT(widthRanges));

    SkFS::Slant slant = SkFS::kUpright_Slant;
    switch (get_int(pattern, FC_SLANT, FC_SLANT_ROMAN)) {
        case FC_SLANT_ROMAN:   slant = SkFS::kUpright_Slant; break;
        case FC_SLANT_ITALIC : slant = SkFS::kItalic_Slant ; break;
        case FC_SLANT_OBLIQUE: slant = SkFS::kOblique_Slant; break;
        default: SkASSERT(false); break;
    }

    return SkFontStyle(weight, width, slant);
}

static void fcpattern_from_skfontstyle(SkFontStyle style, FcPattern* pattern) {
    FCLocker::AssertHeld();

    typedef SkFontStyle SkFS;

    static const MapRanges weightRanges[] = {
        { SkTFixed<SkFS::kThin_Weight>::value,       SkTFixed<FC_WEIGHT_THIN>::value },
        { SkTFixed<SkFS::kExtraLight_Weight>::value, SkTFixed<FC_WEIGHT_EXTRALIGHT>::value },
        { SkTFixed<SkFS::kLight_Weight>::value,      SkTFixed<FC_WEIGHT_LIGHT>::value },
        { SkTFixed<SkFS::kNormal_Weight>::value,     SkTFixed<FC_WEIGHT_REGULAR>::value },
        { SkTFixed<SkFS::kMedium_Weight>::value,     SkTFixed<FC_WEIGHT_MEDIUM>::value },
        { SkTFixed<SkFS::kSemiBold_Weight>::value,   SkTFixed<FC_WEIGHT_DEMIBOLD>::value },
        { SkTFixed<SkFS::kBold_Weight>::value,       SkTFixed<FC_WEIGHT_BOLD>::value },
        { SkTFixed<SkFS::kExtraBold_Weight>::value,  SkTFixed<FC_WEIGHT_EXTRABOLD>::value },
        { SkTFixed<SkFS::kBlack_Weight>::value,      SkTFixed<FC_WEIGHT_BLACK>::value },
        { SkTFixed<SkFS::kExtraBlack_Weight>::value, SkTFixed<FC_WEIGHT_EXTRABLACK>::value },
    };
    int weight = map_ranges(style.weight(), weightRanges, SK_ARRAY_COUNT(weightRanges));

    static const MapRanges widthRanges[] = {
        { SkTFixed<SkFS::kUltraCondensed_Width>::value, SkTFixed<FC_WIDTH_ULTRACONDENSED>::value },
        { SkTFixed<SkFS::kExtraCondensed_Width>::value, SkTFixed<FC_WIDTH_EXTRACONDENSED>::value },
        { SkTFixed<SkFS::kCondensed_Width>::value,      SkTFixed<FC_WIDTH_CONDENSED>::value },
        { SkTFixed<SkFS::kSemiCondensed_Width>::value,  SkTFixed<FC_WIDTH_SEMICONDENSED>::value },
        { SkTFixed<SkFS::kNormal_Width>::value,         SkTFixed<FC_WIDTH_NORMAL>::value },
        { SkTFixed<SkFS::kSemiExpanded_Width>::value,   SkTFixed<FC_WIDTH_SEMIEXPANDED>::value },
        { SkTFixed<SkFS::kExpanded_Width>::value,       SkTFixed<FC_WIDTH_EXPANDED>::value },
        { SkTFixed<SkFS::kExtraExpanded_Width>::value,  SkTFixed<FC_WIDTH_EXTRAEXPANDED>::value },
        { SkTFixed<SkFS::kUltraExpanded_Width>::value,  SkTFixed<FC_WIDTH_ULTRAEXPANDED>::value },
    };
    int width = map_ranges(style.width(), widthRanges, SK_ARRAY_COUNT(widthRanges));

    int slant = FC_SLANT_ROMAN;
    switch (style.slant()) {
        case SkFS::kUpright_Slant: slant = FC_SLANT_ROMAN  ; break;
        case SkFS::kItalic_Slant : slant = FC_SLANT_ITALIC ; break;
        case SkFS::kOblique_Slant: slant = FC_SLANT_OBLIQUE; break;
        default: SkASSERT(false); break;
    }

    FcPatternAddInteger(pattern, FC_WEIGHT, weight);
    FcPatternAddInteger(pattern, FC_WIDTH , width);
    FcPatternAddInteger(pattern, FC_SLANT , slant);
}

class SkTypeface_stream : public SkTypeface_FreeType {
public:
    /** @param data takes ownership of the font data.*/
    SkTypeface_stream(std::unique_ptr<SkFontData> data,
                      SkString familyName, const SkFontStyle& style, bool fixedWidth)
        : INHERITED(style, fixedWidth)
        , fFamilyName(std::move(familyName))
        , fData(std::move(data))
    { }

    void onGetFamilyName(SkString* familyName) const override {
        *familyName = fFamilyName;
    }

    void onGetFontDescriptor(SkFontDescriptor* desc, bool* serialize) const override {
        *serialize = true;
    }

    SkStreamAsset* onOpenStream(int* ttcIndex) const override {
        *ttcIndex = fData->getIndex();
        return fData->getStream()->duplicate();
    }

    std::unique_ptr<SkFontData> onMakeFontData() const override {
        return skstd::make_unique<SkFontData>(*fData);
    }

private:
    SkString fFamilyName;
    const std::unique_ptr<const SkFontData> fData;

    typedef SkTypeface_FreeType INHERITED;
};

class SkTypeface_fontconfig : public SkTypeface_FreeType {
public:
    /** @param pattern takes ownership of the reference. */
    static SkTypeface_fontconfig* Create(FcPattern* pattern) {
        return new SkTypeface_fontconfig(pattern);
    }
    mutable SkAutoFcPattern fPattern;

    void onGetFamilyName(SkString* familyName) const override {
        *familyName = get_string(fPattern, FC_FAMILY);
    }

    void onGetFontDescriptor(SkFontDescriptor* desc, bool* serialize) const override {
        FCLocker lock;
        desc->setFamilyName(get_string(fPattern, FC_FAMILY));
        desc->setFullName(get_string(fPattern, FC_FULLNAME));
        desc->setPostscriptName(get_string(fPattern, FC_POSTSCRIPT_NAME));
        desc->setStyle(this->fontStyle());
        *serialize = false;
    }

    SkStreamAsset* onOpenStream(int* ttcIndex) const override {
        FCLocker lock;
        *ttcIndex = get_int(fPattern, FC_INDEX, 0);
        return SkStream::MakeFromFile(get_string(fPattern, FC_FILE)).release();
    }

    void onFilterRec(SkScalerContextRec* rec) const override {
        const FcMatrix* fcMatrix = get_matrix(fPattern, FC_MATRIX);
        if (fcMatrix) {
            // fPost2x2 is column-major, left handed (y down).
            // FcMatrix is column-major, right handed (y up).
            SkMatrix fm;
            fm.setAll(fcMatrix->xx,-fcMatrix->xy, 0,
                     -fcMatrix->yx, fcMatrix->yy, 0,
                      0           , 0           , 1);

            SkMatrix sm;
            rec->getMatrixFrom2x2(&sm);

            sm.preConcat(fm);
            rec->fPost2x2[0][0] = sm.getScaleX();
            rec->fPost2x2[0][1] = sm.getSkewX();
            rec->fPost2x2[1][0] = sm.getSkewY();
            rec->fPost2x2[1][1] = sm.getScaleY();
        }
        if (get_bool(fPattern, FC_EMBOLDEN)) {
            rec->fFlags |= SkScalerContext::kEmbolden_Flag;
        }
        this->INHERITED::onFilterRec(rec);
    }

    std::unique_ptr<SkAdvancedTypefaceMetrics> onGetAdvancedMetrics() const override {
        std::unique_ptr<SkAdvancedTypefaceMetrics> info =
            this->INHERITED::onGetAdvancedMetrics();

        // Simulated fonts shouldn't be considered to be of the type of their data.
        if (get_matrix(fPattern, FC_MATRIX) || get_bool(fPattern, FC_EMBOLDEN)) {
            info->fType = SkAdvancedTypefaceMetrics::kOther_Font;
        }
        return info;
    }

    ~SkTypeface_fontconfig() override {
        // Hold the lock while unrefing the pattern.
        FCLocker lock;
        fPattern.reset();
    }

private:
    /** @param pattern takes ownership of the reference. */
    SkTypeface_fontconfig(FcPattern* pattern)
        : INHERITED(skfontstyle_from_fcpattern(pattern),
                    FC_PROPORTIONAL != get_int(pattern, FC_SPACING, FC_PROPORTIONAL))
        , fPattern(pattern)
    { }

    typedef SkTypeface_FreeType INHERITED;
};

class SkFontMgr_fontconfig : public SkFontMgr {
    mutable SkAutoFcConfig fFC;
    sk_sp<SkDataTable> fFamilyNames;
    SkTypeface_FreeType::Scanner fScanner;

    class StyleSet : public SkFontStyleSet {
    public:
        /** @param parent does not take ownership of the reference.
         *  @param fontSet takes ownership of the reference.
         */
        StyleSet(const SkFontMgr_fontconfig* parent, FcFontSet* fontSet)
            : fFontMgr(SkRef(parent)), fFontSet(fontSet)
        { }

        ~StyleSet() override {
            // Hold the lock while unrefing the font set.
            FCLocker lock;
            fFontSet.reset();
        }

        int count() override { return fFontSet->nfont; }

        void getStyle(int index, SkFontStyle* style, SkString* styleName) override {
            if (index < 0 || fFontSet->nfont <= index) {
                return;
            }

            FCLocker lock;
            if (style) {
                *style = skfontstyle_from_fcpattern(fFontSet->fonts[index]);
            }
            if (styleName) {
                *styleName = get_string(fFontSet->fonts[index], FC_STYLE);
            }
        }

        SkTypeface* createTypeface(int index) override {
            FCLocker lock;

            FcPattern* match = fFontSet->fonts[index];
            return fFontMgr->createTypefaceFromFcPattern(match);
        }

        SkTypeface* matchStyle(const SkFontStyle& style) override {
            FCLocker lock;

            SkAutoFcPattern pattern;
            fcpattern_from_skfontstyle(style, pattern);
            FcConfigSubstitute(fFontMgr->fFC, pattern, FcMatchPattern);
            FcDefaultSubstitute(pattern);

            FcResult result;
            FcFontSet* fontSets[1] = { fFontSet };
            SkAutoFcPattern match(FcFontSetMatch(fFontMgr->fFC,
                                                 fontSets, SK_ARRAY_COUNT(fontSets),
                                                 pattern, &result));
            if (nullptr == match) {
                return nullptr;
            }

            return fFontMgr->createTypefaceFromFcPattern(match);
        }

    private:
        sk_sp<const SkFontMgr_fontconfig> fFontMgr;
        SkAutoFcFontSet fFontSet;
    };

    static bool FindName(const SkTDArray<const char*>& list, const char* str) {
        int count = list.count();
        for (int i = 0; i < count; ++i) {
            if (!strcmp(list[i], str)) {
                return true;
            }
        }
        return false;
    }

    static sk_sp<SkDataTable> GetFamilyNames(FcConfig* fcconfig) {
        FCLocker lock;

        SkTDArray<const char*> names;
        SkTDArray<size_t> sizes;

        static const FcSetName fcNameSet[] = { FcSetSystem, FcSetApplication };
        for (int setIndex = 0; setIndex < (int)SK_ARRAY_COUNT(fcNameSet); ++setIndex) {
            // Return value of FcConfigGetFonts must not be destroyed.
            FcFontSet* allFonts(FcConfigGetFonts(fcconfig, fcNameSet[setIndex]));
            if (nullptr == allFonts) {
                continue;
            }

            for (int fontIndex = 0; fontIndex < allFonts->nfont; ++fontIndex) {
                FcPattern* current = allFonts->fonts[fontIndex];
                for (int id = 0; ; ++id) {
                    FcChar8* fcFamilyName;
                    FcResult result = FcPatternGetString(current, FC_FAMILY, id, &fcFamilyName);
                    if (FcResultNoId == result) {
                        break;
                    }
                    if (FcResultMatch != result) {
                        continue;
                    }
                    const char* familyName = reinterpret_cast<const char*>(fcFamilyName);
                    if (familyName && !FindName(names, familyName)) {
                        *names.append() = familyName;
                        *sizes.append() = strlen(familyName) + 1;
                    }
                }
            }
        }

        return SkDataTable::MakeCopyArrays((void const *const *)names.begin(),
                                           sizes.begin(), names.count());
    }

    static bool FindByFcPattern(SkTypeface* cached, void* ctx) {
        SkTypeface_fontconfig* cshFace = static_cast<SkTypeface_fontconfig*>(cached);
        FcPattern* ctxPattern = static_cast<FcPattern*>(ctx);
        return FcTrue == FcPatternEqual(cshFace->fPattern, ctxPattern);
    }

    mutable SkMutex fTFCacheMutex;
    mutable SkTypefaceCache fTFCache;
    /** Creates a typeface using a typeface cache.
     *  @param pattern a complete pattern from FcFontRenderPrepare.
     */
    SkTypeface* createTypefaceFromFcPattern(FcPattern* pattern) const {
        FCLocker::AssertHeld();
        SkAutoMutexAcquire ama(fTFCacheMutex);
        SkTypeface* face = fTFCache.findByProcAndRef(FindByFcPattern, pattern);
        if (nullptr == face) {
            FcPatternReference(pattern);
            face = SkTypeface_fontconfig::Create(pattern);
            if (face) {
                fTFCache.add(face);
            }
        }
        return face;
    }

public:
    /** Takes control of the reference to 'config'. */
    explicit SkFontMgr_fontconfig(FcConfig* config)
        : fFC(config ? config : FcInitLoadConfigAndFonts())
        , fFamilyNames(GetFamilyNames(fFC)) { }

    ~SkFontMgr_fontconfig() override {
        // Hold the lock while unrefing the config.
        FCLocker lock;
        fFC.reset();
    }

protected:
    int onCountFamilies() const override {
        return fFamilyNames->count();
    }

    void onGetFamilyName(int index, SkString* familyName) const override {
        familyName->set(fFamilyNames->atStr(index));
    }

    SkFontStyleSet* onCreateStyleSet(int index) const override {
        return this->onMatchFamily(fFamilyNames->atStr(index));
    }

    /** True if any string object value in the font is the same
     *         as a string object value in the pattern.
     */
    static bool AnyMatching(FcPattern* font, FcPattern* pattern, const char* object) {
        FcChar8* fontString;
        FcChar8* patternString;
        FcResult result;
        // Set an arbitrary limit on the number of pattern object values to consider.
        // TODO: re-write this to avoid N*M
        static const int maxId = 16;
        for (int patternId = 0; patternId < maxId; ++patternId) {
            result = FcPatternGetString(pattern, object, patternId, &patternString);
            if (FcResultNoId == result) {
                break;
            }
            if (FcResultMatch != result) {
                continue;
            }
            for (int fontId = 0; fontId < maxId; ++fontId) {
                result = FcPatternGetString(font, object, fontId, &fontString);
                if (FcResultNoId == result) {
                    break;
                }
                if (FcResultMatch != result) {
                    continue;
                }
                if (0 == FcStrCmpIgnoreCase(patternString, fontString)) {
                    return true;
                }
            }
        }
        return false;
    }

    static bool FontAccessible(FcPattern* font) {
        // FontConfig can return fonts which are unreadable.
        const char* filename = get_string(font, FC_FILE, nullptr);
        if (nullptr == filename) {
            return false;
        }
        return sk_exists(filename, kRead_SkFILE_Flag);
    }

    static bool FontFamilyNameMatches(FcPattern* font, FcPattern* pattern) {
        return AnyMatching(font, pattern, FC_FAMILY);
    }

    static bool FontContainsCharacter(FcPattern* font, uint32_t character) {
        FcResult result;
        FcCharSet* matchCharSet;
        for (int charSetId = 0; ; ++charSetId) {
            result = FcPatternGetCharSet(font, FC_CHARSET, charSetId, &matchCharSet);
            if (FcResultNoId == result) {
                break;
            }
            if (FcResultMatch != result) {
                continue;
            }
            if (FcCharSetHasChar(matchCharSet, character)) {
                return true;
            }
        }
        return false;
    }

    SkFontStyleSet* onMatchFamily(const char familyName[]) const override {
        if (!familyName) {
            return nullptr;
        }
        FCLocker lock;

        SkAutoFcPattern pattern;
        FcPatternAddString(pattern, FC_FAMILY, (FcChar8*)familyName);
        FcConfigSubstitute(fFC, pattern, FcMatchPattern);
        FcDefaultSubstitute(pattern);

        FcPattern* matchPattern;
        SkAutoFcPattern strongPattern(nullptr);
        if (familyName) {
            strongPattern.reset(FcPatternDuplicate(pattern));
            remove_weak(strongPattern, FC_FAMILY);
            matchPattern = strongPattern;
        } else {
            matchPattern = pattern;
        }

        SkAutoFcFontSet matches;
        // TODO: Some families have 'duplicates' due to symbolic links.
        // The patterns are exactly the same except for the FC_FILE.
        // It should be possible to collapse these patterns by normalizing.
        static const FcSetName fcNameSet[] = { FcSetSystem, FcSetApplication };
        for (int setIndex = 0; setIndex < (int)SK_ARRAY_COUNT(fcNameSet); ++setIndex) {
            // Return value of FcConfigGetFonts must not be destroyed.
            FcFontSet* allFonts(FcConfigGetFonts(fFC, fcNameSet[setIndex]));
            if (nullptr == allFonts) {
                continue;
            }

            for (int fontIndex = 0; fontIndex < allFonts->nfont; ++fontIndex) {
                FcPattern* font = allFonts->fonts[fontIndex];
                if (FontAccessible(font) && FontFamilyNameMatches(font, matchPattern)) {
                    FcFontSetAdd(matches, FcFontRenderPrepare(fFC, pattern, font));
                }
            }
        }

        return new StyleSet(this, matches.release());
    }

    virtual SkTypeface* onMatchFamilyStyle(const char familyName[],
                                           const SkFontStyle& style) const override
    {
        FCLocker lock;

        SkAutoFcPattern pattern;
        FcPatternAddString(pattern, FC_FAMILY, (FcChar8*)familyName);
        fcpattern_from_skfontstyle(style, pattern);
        FcConfigSubstitute(fFC, pattern, FcMatchPattern);
        FcDefaultSubstitute(pattern);

        // We really want to match strong (prefered) and same (acceptable) only here.
        // If a family name was specified, assume that any weak matches after the last strong match
        // are weak (default) and ignore them.
        // The reason for is that after substitution the pattern for 'sans-serif' looks like
        // "wwwwwwwwwwwwwwswww" where there are many weak but preferred names, followed by defaults.
        // So it is possible to have weakly matching but preferred names.
        // In aliases, bindings are weak by default, so this is easy and common.
        // If no family name was specified, we'll probably only get weak matches, but that's ok.
        FcPattern* matchPattern;
        SkAutoFcPattern strongPattern(nullptr);
        if (familyName) {
            strongPattern.reset(FcPatternDuplicate(pattern));
            remove_weak(strongPattern, FC_FAMILY);
            matchPattern = strongPattern;
        } else {
            matchPattern = pattern;
        }

        FcResult result;
        SkAutoFcPattern font(FcFontMatch(fFC, pattern, &result));
        if (nullptr == font || !FontAccessible(font) || !FontFamilyNameMatches(font, matchPattern)) {
            return nullptr;
        }

        return createTypefaceFromFcPattern(font);
    }

    virtual SkTypeface* onMatchFamilyStyleCharacter(const char familyName[],
                                                    const SkFontStyle& style,
                                                    const char* bcp47[],
                                                    int bcp47Count,
                                                    SkUnichar character) const override
    {
        FCLocker lock;

        SkAutoFcPattern pattern;
        if (familyName) {
            FcValue familyNameValue;
            familyNameValue.type = FcTypeString;
            familyNameValue.u.s = reinterpret_cast<const FcChar8*>(familyName);
            FcPatternAddWeak(pattern, FC_FAMILY, familyNameValue, FcFalse);
        }
        fcpattern_from_skfontstyle(style, pattern);

        SkAutoFcCharSet charSet;
        FcCharSetAddChar(charSet, character);
        FcPatternAddCharSet(pattern, FC_CHARSET, charSet);

        if (bcp47Count > 0) {
            SkASSERT(bcp47);
            SkAutoFcLangSet langSet;
            for (int i = bcp47Count; i --> 0;) {
                FcLangSetAdd(langSet, (const FcChar8*)bcp47[i]);
            }
            FcPatternAddLangSet(pattern, FC_LANG, langSet);
        }

        FcConfigSubstitute(fFC, pattern, FcMatchPattern);
        FcDefaultSubstitute(pattern);

        FcResult result;
        SkAutoFcPattern font(FcFontMatch(fFC, pattern, &result));
        if (nullptr == font || !FontAccessible(font) || !FontContainsCharacter(font, character)) {
            return nullptr;
        }

        return createTypefaceFromFcPattern(font);
    }

    virtual SkTypeface* onMatchFaceStyle(const SkTypeface* typeface,
                                         const SkFontStyle& style) const override
    {
        //TODO: should the SkTypeface_fontconfig know its family?
        const SkTypeface_fontconfig* fcTypeface =
                static_cast<const SkTypeface_fontconfig*>(typeface);
        return this->matchFamilyStyle(get_string(fcTypeface->fPattern, FC_FAMILY), style);
    }

    SkTypeface* onCreateFromStream(SkStreamAsset* bareStream, int ttcIndex) const override {
        std::unique_ptr<SkStreamAsset> stream(bareStream);
        const size_t length = stream->getLength();
        if (length <= 0 || (1u << 30) < length) {
            return nullptr;
        }

        SkString name;
        SkFontStyle style;
        bool isFixedWidth = false;
        if (!fScanner.scanFont(stream.get(), ttcIndex, &name, &style, &isFixedWidth, nullptr)) {
            return nullptr;
        }

        auto data = skstd::make_unique<SkFontData>(std::move(stream), ttcIndex, nullptr, 0);
        return new SkTypeface_stream(std::move(data), std::move(name), style, isFixedWidth);
    }

    SkTypeface* onCreateFromStream(SkStreamAsset* s, const SkFontArguments& args) const override {
        using Scanner = SkTypeface_FreeType::Scanner;
        std::unique_ptr<SkStreamAsset> stream(s);
        bool isFixedPitch;
        SkFontStyle style;
        SkString name;
        Scanner::AxisDefinitions axisDefinitions;
        if (!fScanner.scanFont(stream.get(), args.getCollectionIndex(),
                               &name, &style, &isFixedPitch, &axisDefinitions))
        {
            return nullptr;
        }

        SkAutoSTMalloc<4, SkFixed> axisValues(axisDefinitions.count());
        Scanner::computeAxisValues(axisDefinitions, args.getVariationDesignPosition(),
                                   axisValues, name);

        auto data = skstd::make_unique<SkFontData>(std::move(stream), args.getCollectionIndex(),
                                                   axisValues.get(), axisDefinitions.count());
        return new SkTypeface_stream(std::move(data), std::move(name), style, isFixedPitch);
    }

    SkTypeface* onCreateFromData(SkData* data, int ttcIndex) const override {
        return this->createFromStream(new SkMemoryStream(sk_ref_sp(data)), ttcIndex);
    }

    SkTypeface* onCreateFromFile(const char path[], int ttcIndex) const override {
        return this->createFromStream(SkStream::MakeFromFile(path).release(), ttcIndex);
    }

    SkTypeface* onCreateFromFontData(std::unique_ptr<SkFontData> fontData) const override {
        SkStreamAsset* stream(fontData->getStream());
        const size_t length = stream->getLength();
        if (length <= 0 || (1u << 30) < length) {
            return nullptr;
        }

        const int ttcIndex = fontData->getIndex();
        SkString name;
        SkFontStyle style;
        bool isFixedWidth = false;
        if (!fScanner.scanFont(stream, ttcIndex, &name, &style, &isFixedWidth, nullptr)) {
            return nullptr;
        }

        return new SkTypeface_stream(std::move(fontData), std::move(name), style, isFixedWidth);
    }

    SkTypeface* onLegacyCreateTypeface(const char familyName[], SkFontStyle style) const override {
        sk_sp<SkTypeface> typeface(this->matchFamilyStyle(familyName, style));
        if (typeface.get()) {
            return typeface.release();
        }

        return this->matchFamilyStyle(nullptr, style);
    }
};

SK_API sk_sp<SkFontMgr> SkFontMgr_New_FontConfig(FcConfig* fc) {
    return sk_make_sp<SkFontMgr_fontconfig>(fc);
}