aboutsummaryrefslogtreecommitdiffhomepage
path: root/src/core/SkGlyphCache.cpp
blob: 9f0dfba4272f185cc5740f13c9e4eae33dd68ef2 (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

/*
 * Copyright 2006 The Android Open Source Project
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */


#include "SkGlyphCache.h"
#include "SkGraphics.h"
#include "SkPaint.h"
#include "SkTemplates.h"

//#define SPEW_PURGE_STATUS
//#define USE_CACHE_HASH
//#define RECORD_HASH_EFFICIENCY

bool gSkSuppressFontCachePurgeSpew;

///////////////////////////////////////////////////////////////////////////////

#ifdef RECORD_HASH_EFFICIENCY
    static uint32_t gHashSuccess;
    static uint32_t gHashCollision;

    static void RecordHashSuccess() {
        gHashSuccess += 1;
    }

    static void RecordHashCollisionIf(bool pred) {
        if (pred) {
            gHashCollision += 1;

            uint32_t total = gHashSuccess + gHashCollision;
            SkDebugf("Font Cache Hash success rate: %d%%\n",
                     100 * gHashSuccess / total);
        }
    }
#else
    #define RecordHashSuccess() (void)0
    #define RecordHashCollisionIf(pred) (void)0
#endif
#define RecordHashCollision() RecordHashCollisionIf(true)

///////////////////////////////////////////////////////////////////////////////

#define kMinGlphAlloc       (sizeof(SkGlyph) * 64)
#define kMinImageAlloc      (24 * 64)   // should be pointsize-dependent

#define METRICS_RESERVE_COUNT  128  // so we don't grow this array a lot

SkGlyphCache::SkGlyphCache(const SkDescriptor* desc)
        : fGlyphAlloc(kMinGlphAlloc), fImageAlloc(kMinImageAlloc) {
    fPrev = fNext = NULL;

    fDesc = desc->copy();
    fScalerContext = SkScalerContext::Create(desc);
    fScalerContext->getFontMetrics(NULL, &fFontMetricsY);

    // init to 0 so that all of the pointers will be null
    memset(fGlyphHash, 0, sizeof(fGlyphHash));
    // init with 0xFF so that the charCode field will be -1, which is invalid
    memset(fCharToGlyphHash, 0xFF, sizeof(fCharToGlyphHash));

    fMemoryUsed = sizeof(*this) + kMinGlphAlloc + kMinImageAlloc;

    fGlyphArray.setReserve(METRICS_RESERVE_COUNT);

    fMetricsCount = 0;
    fAdvanceCount = 0;
    fAuxProcList = NULL;
}

SkGlyphCache::~SkGlyphCache() {
    SkGlyph**   gptr = fGlyphArray.begin();
    SkGlyph**   stop = fGlyphArray.end();
    while (gptr < stop) {
        SkPath* path = (*gptr)->fPath;
        if (path) {
            SkDELETE(path);
        }
        gptr += 1;
    }
    SkDescriptor::Free(fDesc);
    SkDELETE(fScalerContext);
    this->invokeAndRemoveAuxProcs();
}

///////////////////////////////////////////////////////////////////////////////

#ifdef SK_DEBUG
#define VALIDATE()  AutoValidate av(this)
#else
#define VALIDATE()
#endif

uint16_t SkGlyphCache::unicharToGlyph(SkUnichar charCode) {
    VALIDATE();
    uint32_t id = SkGlyph::MakeID(charCode);
    const CharGlyphRec& rec = fCharToGlyphHash[ID2HashIndex(id)];

    if (rec.fID == id) {
        return rec.fGlyph->getGlyphID();
    } else {
        return fScalerContext->charToGlyphID(charCode);
    }
}

SkUnichar SkGlyphCache::glyphToUnichar(uint16_t glyphID) {
    return fScalerContext->glyphIDToChar(glyphID);
}

unsigned SkGlyphCache::getGlyphCount() {
    return fScalerContext->getGlyphCount();
}

///////////////////////////////////////////////////////////////////////////////

const SkGlyph& SkGlyphCache::getUnicharAdvance(SkUnichar charCode) {
    VALIDATE();
    uint32_t id = SkGlyph::MakeID(charCode);
    CharGlyphRec* rec = &fCharToGlyphHash[ID2HashIndex(id)];

    if (rec->fID != id) {
        // this ID is based on the UniChar
        rec->fID = id;
        // this ID is based on the glyph index
        id = SkGlyph::MakeID(fScalerContext->charToGlyphID(charCode));
        rec->fGlyph = this->lookupMetrics(id, kJustAdvance_MetricsType);
    }
    return *rec->fGlyph;
}

const SkGlyph& SkGlyphCache::getGlyphIDAdvance(uint16_t glyphID) {
    VALIDATE();
    uint32_t id = SkGlyph::MakeID(glyphID);
    unsigned index = ID2HashIndex(id);
    SkGlyph* glyph = fGlyphHash[index];

    if (NULL == glyph || glyph->fID != id) {
        glyph = this->lookupMetrics(glyphID, kJustAdvance_MetricsType);
        fGlyphHash[index] = glyph;
    }
    return *glyph;
}

///////////////////////////////////////////////////////////////////////////////

const SkGlyph& SkGlyphCache::getUnicharMetrics(SkUnichar charCode) {
    VALIDATE();
    uint32_t id = SkGlyph::MakeID(charCode);
    CharGlyphRec* rec = &fCharToGlyphHash[ID2HashIndex(id)];

    if (rec->fID != id) {
        RecordHashCollisionIf(rec->fGlyph != NULL);
        // this ID is based on the UniChar
        rec->fID = id;
        // this ID is based on the glyph index
        id = SkGlyph::MakeID(fScalerContext->charToGlyphID(charCode));
        rec->fGlyph = this->lookupMetrics(id, kFull_MetricsType);
    } else {
        RecordHashSuccess();
        if (rec->fGlyph->isJustAdvance()) {
            fScalerContext->getMetrics(rec->fGlyph);
        }
    }
    SkASSERT(rec->fGlyph->isFullMetrics());
    return *rec->fGlyph;
}

const SkGlyph& SkGlyphCache::getUnicharMetrics(SkUnichar charCode,
                                               SkFixed x, SkFixed y) {
    VALIDATE();
    uint32_t id = SkGlyph::MakeID(charCode, x, y);
    CharGlyphRec* rec = &fCharToGlyphHash[ID2HashIndex(id)];

    if (rec->fID != id) {
        RecordHashCollisionIf(rec->fGlyph != NULL);
        // this ID is based on the UniChar
        rec->fID = id;
        // this ID is based on the glyph index
        id = SkGlyph::MakeID(fScalerContext->charToGlyphID(charCode), x, y);
        rec->fGlyph = this->lookupMetrics(id, kFull_MetricsType);
    } else {
        RecordHashSuccess();
        if (rec->fGlyph->isJustAdvance()) {
            fScalerContext->getMetrics(rec->fGlyph);
        }
    }
    SkASSERT(rec->fGlyph->isFullMetrics());
    return *rec->fGlyph;
}

const SkGlyph& SkGlyphCache::getGlyphIDMetrics(uint16_t glyphID) {
    VALIDATE();
    uint32_t id = SkGlyph::MakeID(glyphID);
    unsigned index = ID2HashIndex(id);
    SkGlyph* glyph = fGlyphHash[index];

    if (NULL == glyph || glyph->fID != id) {
        RecordHashCollisionIf(glyph != NULL);
        glyph = this->lookupMetrics(glyphID, kFull_MetricsType);
        fGlyphHash[index] = glyph;
    } else {
        RecordHashSuccess();
        if (glyph->isJustAdvance()) {
            fScalerContext->getMetrics(glyph);
        }
    }
    SkASSERT(glyph->isFullMetrics());
    return *glyph;
}

const SkGlyph& SkGlyphCache::getGlyphIDMetrics(uint16_t glyphID,
                                               SkFixed x, SkFixed y) {
    VALIDATE();
    uint32_t id = SkGlyph::MakeID(glyphID, x, y);
    unsigned index = ID2HashIndex(id);
    SkGlyph* glyph = fGlyphHash[index];

    if (NULL == glyph || glyph->fID != id) {
        RecordHashCollisionIf(glyph != NULL);
        glyph = this->lookupMetrics(id, kFull_MetricsType);
        fGlyphHash[index] = glyph;
    } else {
        RecordHashSuccess();
        if (glyph->isJustAdvance()) {
            fScalerContext->getMetrics(glyph);
        }
    }
    SkASSERT(glyph->isFullMetrics());
    return *glyph;
}

SkGlyph* SkGlyphCache::lookupMetrics(uint32_t id, MetricsType mtype) {
    SkGlyph* glyph;

    int     hi = 0;
    int     count = fGlyphArray.count();

    if (count) {
        SkGlyph**   gptr = fGlyphArray.begin();
        int     lo = 0;

        hi = count - 1;
        while (lo < hi) {
            int mid = (hi + lo) >> 1;
            if (gptr[mid]->fID < id) {
                lo = mid + 1;
            } else {
                hi = mid;
            }
        }
        glyph = gptr[hi];
        if (glyph->fID == id) {
            if (kFull_MetricsType == mtype && glyph->isJustAdvance()) {
                fScalerContext->getMetrics(glyph);
            }
            return glyph;
        }

        // check if we need to bump hi before falling though to the allocator
        if (glyph->fID < id) {
            hi += 1;
        }
    }

    // not found, but hi tells us where to inser the new glyph
    fMemoryUsed += sizeof(SkGlyph);

    glyph = (SkGlyph*)fGlyphAlloc.alloc(sizeof(SkGlyph),
                                        SkChunkAlloc::kThrow_AllocFailType);
    glyph->init(id);
    *fGlyphArray.insert(hi) = glyph;

    if (kJustAdvance_MetricsType == mtype) {
        fScalerContext->getAdvance(glyph);
        fAdvanceCount += 1;
    } else {
        SkASSERT(kFull_MetricsType == mtype);
        fScalerContext->getMetrics(glyph);
        fMetricsCount += 1;
    }

    return glyph;
}

const void* SkGlyphCache::findImage(const SkGlyph& glyph) {
    if (glyph.fWidth > 0 && glyph.fWidth < kMaxGlyphWidth) {
        if (glyph.fImage == NULL) {
            size_t  size = glyph.computeImageSize();
            const_cast<SkGlyph&>(glyph).fImage = fImageAlloc.alloc(size,
                                        SkChunkAlloc::kReturnNil_AllocFailType);
            // check that alloc() actually succeeded
            if (glyph.fImage) {
                fScalerContext->getImage(glyph);
                // TODO: the scaler may have changed the maskformat during
                // getImage (e.g. from AA or LCD to BW) which means we may have
                // overallocated the buffer. Check if the new computedImageSize
                // is smaller, and if so, strink the alloc size in fImageAlloc.
                fMemoryUsed += size;
            }
        }
    }
    return glyph.fImage;
}

const SkPath* SkGlyphCache::findPath(const SkGlyph& glyph) {
    if (glyph.fWidth) {
        if (glyph.fPath == NULL) {
            const_cast<SkGlyph&>(glyph).fPath = SkNEW(SkPath);
            fScalerContext->getPath(glyph, glyph.fPath);
            fMemoryUsed += sizeof(SkPath) +
                    glyph.fPath->getPoints(NULL, 0x7FFFFFFF) * sizeof(SkPoint);
        }
    }
    return glyph.fPath;
}

///////////////////////////////////////////////////////////////////////////////

bool SkGlyphCache::getAuxProcData(void (*proc)(void*), void** dataPtr) const {
    const AuxProcRec* rec = fAuxProcList;
    while (rec) {
        if (rec->fProc == proc) {
            if (dataPtr) {
                *dataPtr = rec->fData;
            }
            return true;
        }
        rec = rec->fNext;
    }
    return false;
}

void SkGlyphCache::setAuxProc(void (*proc)(void*), void* data) {
    if (proc == NULL) {
        return;
    }

    AuxProcRec* rec = fAuxProcList;
    while (rec) {
        if (rec->fProc == proc) {
            rec->fData = data;
            return;
        }
        rec = rec->fNext;
    }
    // not found, create a new rec
    rec = SkNEW(AuxProcRec);
    rec->fProc = proc;
    rec->fData = data;
    rec->fNext = fAuxProcList;
    fAuxProcList = rec;
}

void SkGlyphCache::removeAuxProc(void (*proc)(void*)) {
    AuxProcRec* rec = fAuxProcList;
    AuxProcRec* prev = NULL;
    while (rec) {
        AuxProcRec* next = rec->fNext;
        if (rec->fProc == proc) {
            if (prev) {
                prev->fNext = next;
            } else {
                fAuxProcList = next;
            }
            SkDELETE(rec);
            return;
        }
        prev = rec;
        rec = next;
    }
}

void SkGlyphCache::invokeAndRemoveAuxProcs() {
    AuxProcRec* rec = fAuxProcList;
    while (rec) {
        rec->fProc(rec->fData);
        AuxProcRec* next = rec->fNext;
        SkDELETE(rec);
        rec = next;
    }
}

///////////////////////////////////////////////////////////////////////////////
///////////////////////////////////////////////////////////////////////////////

#ifdef USE_CACHE_HASH
    #define HASH_BITCOUNT   6
    #define HASH_COUNT      (1 << HASH_BITCOUNT)
    #define HASH_MASK       (HASH_COUNT - 1)

    static unsigned desc_to_hashindex(const SkDescriptor* desc)
    {
        SkASSERT(HASH_MASK < 256);  // since our munging reduces to 8 bits

        uint32_t n = *(const uint32_t*)desc;    //desc->getChecksum();
        SkASSERT(n == desc->getChecksum());

        // don't trust that the low bits of checksum vary enough, so...
        n ^= (n >> 24) ^ (n >> 16) ^ (n >> 8) ^ (n >> 30);

        return n & HASH_MASK;
    }
#endif

#include "SkThread.h"

class SkGlyphCache_Globals {
public:
    SkGlyphCache_Globals() {
        fHead = NULL;
        fTotalMemoryUsed = 0;
#ifdef USE_CACHE_HASH
        sk_bzero(fHash, sizeof(fHash));
#endif
    }

    SkMutex         fMutex;
    SkGlyphCache*   fHead;
    size_t          fTotalMemoryUsed;
#ifdef USE_CACHE_HASH
    SkGlyphCache*   fHash[HASH_COUNT];
#endif

#ifdef SK_DEBUG
    void validate() const;
#else
    void validate() const {}
#endif
};

static SkGlyphCache_Globals& getGlobals() {
    // we leak this, so we don't incur any shutdown cost of the destructor
    static SkGlyphCache_Globals* gGlobals = new SkGlyphCache_Globals;
    return *gGlobals;
}

void SkGlyphCache::VisitAllCaches(bool (*proc)(SkGlyphCache*, void*),
                                  void* context) {
    SkGlyphCache_Globals& globals = getGlobals();
    SkAutoMutexAcquire    ac(globals.fMutex);
    SkGlyphCache*         cache;

    globals.validate();

    for (cache = globals.fHead; cache != NULL; cache = cache->fNext) {
        if (proc(cache, context)) {
            break;
        }
    }

    globals.validate();
}

/*  This guy calls the visitor from within the mutext lock, so the visitor
    cannot:
    - take too much time
    - try to acquire the mutext again
    - call a fontscaler (which might call into the cache)
*/
SkGlyphCache* SkGlyphCache::VisitCache(const SkDescriptor* desc,
                              bool (*proc)(const SkGlyphCache*, void*),
                              void* context) {
    SkASSERT(desc);

    SkGlyphCache_Globals& globals = getGlobals();
    SkAutoMutexAcquire    ac(globals.fMutex);
    SkGlyphCache*         cache;
    bool                  insideMutex = true;

    globals.validate();

#ifdef USE_CACHE_HASH
    SkGlyphCache** hash = globals.fHash;
    unsigned index = desc_to_hashindex(desc);
    cache = hash[index];
    if (cache && *cache->fDesc == *desc) {
        cache->detach(&globals.fHead);
        goto FOUND_IT;
    }
#endif

    for (cache = globals.fHead; cache != NULL; cache = cache->fNext) {
        if (cache->fDesc->equals(*desc)) {
            cache->detach(&globals.fHead);
            goto FOUND_IT;
        }
    }

    /* Release the mutex now, before we create a new entry (which might have
        side-effects like trying to access the cache/mutex (yikes!)
    */
    ac.release();           // release the mutex now
    insideMutex = false;    // can't use globals anymore

    cache = SkNEW_ARGS(SkGlyphCache, (desc));

FOUND_IT:

    AutoValidate av(cache);

    if (proc(cache, context)) {   // stay detached
        if (insideMutex) {
            SkASSERT(globals.fTotalMemoryUsed >= cache->fMemoryUsed);
            globals.fTotalMemoryUsed -= cache->fMemoryUsed;
#ifdef USE_CACHE_HASH
            hash[index] = NULL;
#endif
        }
    } else {                        // reattach
        if (insideMutex) {
            cache->attachToHead(&globals.fHead);
#ifdef USE_CACHE_HASH
            hash[index] = cache;
#endif
        } else {
            AttachCache(cache);
        }
        cache = NULL;
    }
    return cache;
}

void SkGlyphCache::AttachCache(SkGlyphCache* cache) {
    SkASSERT(cache);
    SkASSERT(cache->fNext == NULL);

    SkGlyphCache_Globals& globals = getGlobals();
    SkAutoMutexAcquire    ac(globals.fMutex);

    globals.validate();
    cache->validate();

    // if we have a fixed budget for our cache, do a purge here
    {
        size_t allocated = globals.fTotalMemoryUsed + cache->fMemoryUsed;
        size_t budgeted = SkGraphics::GetFontCacheLimit();
        if (allocated > budgeted) {
            (void)InternalFreeCache(&globals, allocated - budgeted);
        }
    }

    cache->attachToHead(&globals.fHead);
    globals.fTotalMemoryUsed += cache->fMemoryUsed;

#ifdef USE_CACHE_HASH
    unsigned index = desc_to_hashindex(cache->fDesc);
    SkASSERT(globals.fHash[index] != cache);
    globals.fHash[index] = cache;
#endif

    globals.validate();
}

size_t SkGlyphCache::GetCacheUsed() {
    SkGlyphCache_Globals& globals = getGlobals();
    SkAutoMutexAcquire  ac(globals.fMutex);

    return SkGlyphCache::ComputeMemoryUsed(globals.fHead);
}

bool SkGlyphCache::SetCacheUsed(size_t bytesUsed) {
    size_t curr = SkGlyphCache::GetCacheUsed();

    if (curr > bytesUsed) {
        SkGlyphCache_Globals& globals = getGlobals();
        SkAutoMutexAcquire  ac(globals.fMutex);

        return InternalFreeCache(&globals, curr - bytesUsed) > 0;
    }
    return false;
}

///////////////////////////////////////////////////////////////////////////////

SkGlyphCache* SkGlyphCache::FindTail(SkGlyphCache* cache) {
    if (cache) {
        while (cache->fNext) {
            cache = cache->fNext;
        }
    }
    return cache;
}

size_t SkGlyphCache::ComputeMemoryUsed(const SkGlyphCache* head) {
    size_t size = 0;

    while (head != NULL) {
        size += head->fMemoryUsed;
        head = head->fNext;
    }
    return size;
}

#ifdef SK_DEBUG
void SkGlyphCache_Globals::validate() const {
    size_t computed = SkGlyphCache::ComputeMemoryUsed(fHead);
    if (fTotalMemoryUsed != computed) {
        printf("total %d, computed %d\n", (int)fTotalMemoryUsed, (int)computed);
    }
    SkASSERT(fTotalMemoryUsed == computed);
}
#endif

size_t SkGlyphCache::InternalFreeCache(SkGlyphCache_Globals* globals,
                                       size_t bytesNeeded) {
    globals->validate();

    size_t  bytesFreed = 0;
    int     count = 0;

    // don't do any "small" purges
    size_t minToPurge = globals->fTotalMemoryUsed >> 2;
    if (bytesNeeded < minToPurge)
        bytesNeeded = minToPurge;

    SkGlyphCache* cache = FindTail(globals->fHead);
    while (cache != NULL && bytesFreed < bytesNeeded) {
        SkGlyphCache* prev = cache->fPrev;
        bytesFreed += cache->fMemoryUsed;

#ifdef USE_CACHE_HASH
        unsigned index = desc_to_hashindex(cache->fDesc);
        if (cache == globals->fHash[index]) {
            globals->fHash[index] = NULL;
        }
#endif

        cache->detach(&globals->fHead);
        SkDELETE(cache);
        cache = prev;
        count += 1;
    }

    SkASSERT(bytesFreed <= globals->fTotalMemoryUsed);
    globals->fTotalMemoryUsed -= bytesFreed;
    globals->validate();

#ifdef SPEW_PURGE_STATUS
    if (count && !gSkSuppressFontCachePurgeSpew) {
        SkDebugf("purging %dK from font cache [%d entries]\n",
                 (int)(bytesFreed >> 10), count);
    }
#endif

    return bytesFreed;
}

///////////////////////////////////////////////////////////////////////////////
#ifdef SK_DEBUG

void SkGlyphCache::validate() const {
    int count = fGlyphArray.count();
    for (int i = 0; i < count; i++) {
        const SkGlyph* glyph = fGlyphArray[i];
        SkASSERT(glyph);
        SkASSERT(fGlyphAlloc.contains(glyph));
        if (glyph->fImage) {
            SkASSERT(fImageAlloc.contains(glyph->fImage));
        }
    }
}

#endif