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1 /*
2  * Copyright 2016 Google Inc.
3  *
4  * Use of this source code is governed by a BSD-style license that can be
5  * found in the LICENSE file.
6  */
7 
8 #include "modules/skshaper/include/SkShaper_harfbuzz.h"
9 
10 #include "include/core/SkData.h"
11 #include "include/core/SkFont.h"
12 #include "include/core/SkFontArguments.h"
13 #include "include/core/SkFontMetrics.h"
14 #include "include/core/SkFontMgr.h"
15 #include "include/core/SkFontTypes.h"
16 #include "include/core/SkPaint.h"
17 #include "include/core/SkPoint.h"
18 #include "include/core/SkRect.h"
19 #include "include/core/SkRefCnt.h"
20 #include "include/core/SkScalar.h"
21 #include "include/core/SkSpan.h"
22 #include "include/core/SkStream.h"
23 #include "include/core/SkString.h"
24 #include "include/core/SkTypeface.h"
25 #include "include/core/SkTypes.h"
26 #include "include/private/base/SkDebug.h"
27 #include "include/private/base/SkMalloc.h"
28 #include "include/private/base/SkMutex.h"
29 #include "include/private/base/SkTArray.h"
30 #include "include/private/base/SkTemplates.h"
31 #include "include/private/base/SkTo.h"
32 #include "include/private/base/SkTypeTraits.h"
33 #include "modules/skshaper/include/SkShaper.h"
34 #include "modules/skunicode/include/SkUnicode.h"
35 #include "src/base/SkTDPQueue.h"
36 #include "src/base/SkUTF.h"
37 #include "src/core/SkLRUCache.h"
38 
39 #if !defined(SK_DISABLE_LEGACY_SKSHAPER_FUNCTIONS)
40 #include "modules/skshaper/include/SkShaper_skunicode.h"
41 #endif
42 
43 #include <hb-ot.h>
44 #include <hb.h>
45 
46 #include <cstdint>
47 #include <cstring>
48 #include <memory>
49 #include <type_traits>
50 #include <utility>
51 
52 using namespace skia_private;
53 
54 // HB_FEATURE_GLOBAL_START and HB_FEATURE_GLOBAL_END were not added until HarfBuzz 2.0
55 // They would have always worked, they just hadn't been named yet.
56 #if !defined(HB_FEATURE_GLOBAL_START)
57 #  define HB_FEATURE_GLOBAL_START 0
58 #endif
59 #if !defined(HB_FEATURE_GLOBAL_END)
60 # define HB_FEATURE_GLOBAL_END ((unsigned int) -1)
61 #endif
62 
63 namespace {
64 using HBBlob   = std::unique_ptr<hb_blob_t  , SkFunctionObject<hb_blob_destroy>  >;
65 using HBFace   = std::unique_ptr<hb_face_t  , SkFunctionObject<hb_face_destroy>  >;
66 using HBFont   = std::unique_ptr<hb_font_t  , SkFunctionObject<hb_font_destroy>  >;
67 using HBBuffer = std::unique_ptr<hb_buffer_t, SkFunctionObject<hb_buffer_destroy>>;
68 
69 using SkUnicodeBreak = std::unique_ptr<SkBreakIterator>;
70 
skhb_position(SkScalar value)71 hb_position_t skhb_position(SkScalar value) {
72     // Treat HarfBuzz hb_position_t as 16.16 fixed-point.
73     constexpr int kHbPosition1 = 1 << 16;
74     return SkScalarRoundToInt(value * kHbPosition1);
75 }
76 
skhb_glyph(hb_font_t * hb_font,void * font_data,hb_codepoint_t unicode,hb_codepoint_t variation_selector,hb_codepoint_t * glyph,void * user_data)77 hb_bool_t skhb_glyph(hb_font_t* hb_font,
78                      void* font_data,
79                      hb_codepoint_t unicode,
80                      hb_codepoint_t variation_selector,
81                      hb_codepoint_t* glyph,
82                      void* user_data) {
83 #ifdef ENABLE_TEXT_ENHANCE
84     RSFont& font = *reinterpret_cast<RSFont*>(font_data);
85     *glyph = font.UnicharToGlyph(unicode);
86 #else
87     SkFont& font = *reinterpret_cast<SkFont*>(font_data);
88     *glyph = font.unicharToGlyph(unicode);
89 #endif
90     return *glyph != 0;
91 }
92 
skhb_nominal_glyph(hb_font_t * hb_font,void * font_data,hb_codepoint_t unicode,hb_codepoint_t * glyph,void * user_data)93 hb_bool_t skhb_nominal_glyph(hb_font_t* hb_font,
94                              void* font_data,
95                              hb_codepoint_t unicode,
96                              hb_codepoint_t* glyph,
97                              void* user_data) {
98   return skhb_glyph(hb_font, font_data, unicode, 0, glyph, user_data);
99 }
100 
skhb_nominal_glyphs(hb_font_t * hb_font,void * font_data,unsigned int count,const hb_codepoint_t * unicodes,unsigned int unicode_stride,hb_codepoint_t * glyphs,unsigned int glyph_stride,void * user_data)101 unsigned skhb_nominal_glyphs(hb_font_t *hb_font, void *font_data,
102                              unsigned int count,
103                              const hb_codepoint_t *unicodes,
104                              unsigned int unicode_stride,
105                              hb_codepoint_t *glyphs,
106                              unsigned int glyph_stride,
107                              void *user_data) {
108 #ifdef ENABLE_TEXT_ENHANCE
109     RSFont& font = *reinterpret_cast<RSFont*>(font_data);
110 #else
111     SkFont& font = *reinterpret_cast<SkFont*>(font_data);
112 #endif
113 
114     // Batch call textToGlyphs since entry cost is not cheap.
115     // Copy requred because textToGlyphs is dense and hb is strided.
116     AutoSTMalloc<256, SkUnichar> unicode(count);
117     for (unsigned i = 0; i < count; i++) {
118         unicode[i] = *unicodes;
119         unicodes = SkTAddOffset<const hb_codepoint_t>(unicodes, unicode_stride);
120     }
121     AutoSTMalloc<256, SkGlyphID> glyph(count);
122 #ifdef ENABLE_TEXT_ENHANCE
123     font.TextToGlyphs(unicode.get(), count * sizeof(SkUnichar), RSDrawing::TextEncoding::UTF32,
124                       glyph.get(), count);
125 #else
126     font.textToGlyphs(unicode.get(), count * sizeof(SkUnichar), SkTextEncoding::kUTF32,
127                         glyph.get(), count);
128 #endif
129 
130     // Copy the results back to the sparse array.
131     unsigned int done;
132     for (done = 0; done < count && glyph[done] != 0; done++) {
133         *glyphs = glyph[done];
134         glyphs = SkTAddOffset<hb_codepoint_t>(glyphs, glyph_stride);
135     }
136     // return 'done' to allow HarfBuzz to synthesize with NFC and spaces, return 'count' to avoid
137     return done;
138 }
139 
skhb_glyph_h_advance(hb_font_t * hb_font,void * font_data,hb_codepoint_t hbGlyph,void * user_data)140 hb_position_t skhb_glyph_h_advance(hb_font_t* hb_font,
141                                    void* font_data,
142                                    hb_codepoint_t hbGlyph,
143                                    void* user_data) {
144 #ifdef ENABLE_TEXT_ENHANCE
145     RSFont& font = *reinterpret_cast<RSFont*>(font_data);
146 #else
147     SkFont& font = *reinterpret_cast<SkFont*>(font_data);
148 #endif
149 
150     SkScalar advance;
151     SkGlyphID skGlyph = SkTo<SkGlyphID>(hbGlyph);
152 
153 #ifdef ENABLE_TEXT_ENHANCE
154     font.GetWidths(&skGlyph, 1, &advance);
155     if (!font.IsSubpixel()) {
156         advance = SkScalarRoundToInt(advance);
157     }
158 #else
159     font.getWidths(&skGlyph, 1, &advance);
160     if (!font.isSubpixel()) {
161         advance = SkScalarRoundToInt(advance);
162     }
163 #endif
164     return skhb_position(advance);
165 }
166 
skhb_glyph_h_advances(hb_font_t * hb_font,void * font_data,unsigned count,const hb_codepoint_t * glyphs,unsigned int glyph_stride,hb_position_t * advances,unsigned int advance_stride,void * user_data)167 void skhb_glyph_h_advances(hb_font_t* hb_font,
168                            void* font_data,
169                            unsigned count,
170                            const hb_codepoint_t* glyphs,
171                            unsigned int glyph_stride,
172                            hb_position_t* advances,
173                            unsigned int advance_stride,
174                            void* user_data) {
175 #ifdef ENABLE_TEXT_ENHANCE
176     RSFont& font = *reinterpret_cast<RSFont*>(font_data);
177 #else
178     SkFont& font = *reinterpret_cast<SkFont*>(font_data);
179 #endif
180 
181     // Batch call getWidths since entry cost is not cheap.
182     // Copy requred because getWidths is dense and hb is strided.
183     AutoSTMalloc<256, SkGlyphID> glyph(count);
184     for (unsigned i = 0; i < count; i++) {
185         glyph[i] = *glyphs;
186         glyphs = SkTAddOffset<const hb_codepoint_t>(glyphs, glyph_stride);
187     }
188     AutoSTMalloc<256, SkScalar> advance(count);
189 #ifdef ENABLE_TEXT_ENHANCE
190     font.GetWidths(glyph.get(), count, advance.get());
191 #else
192     font.getWidths(glyph.get(), count, advance.get());
193 #endif
194 
195 #ifdef ENABLE_TEXT_ENHANCE
196     if (!font.IsSubpixel()) {
197 #else
198     if (!font.isSubpixel()) {
199 #endif
200         for (unsigned i = 0; i < count; i++) {
201             advance[i] = SkScalarRoundToInt(advance[i]);
202         }
203     }
204 
205     // Copy the results back to the sparse array.
206     for (unsigned i = 0; i < count; i++) {
207         *advances = skhb_position(advance[i]);
208         advances = SkTAddOffset<hb_position_t>(advances, advance_stride);
209     }
210 }
211 
212 // HarfBuzz callback to retrieve glyph extents, mainly used by HarfBuzz for
213 // fallback mark positioning, i.e. the situation when the font does not have
214 // mark anchors or other mark positioning rules, but instead HarfBuzz is
215 // supposed to heuristically place combining marks around base glyphs. HarfBuzz
216 // does this by measuring "ink boxes" of glyphs, and placing them according to
217 // Unicode mark classes. Above, below, centered or left or right, etc.
218 hb_bool_t skhb_glyph_extents(hb_font_t* hb_font,
219                              void* font_data,
220                              hb_codepoint_t hbGlyph,
221                              hb_glyph_extents_t* extents,
222                              void* user_data) {
223 #ifdef ENABLE_TEXT_ENHANCE
224     RSFont& font = *reinterpret_cast<RSFont*>(font_data);
225 #else
226     SkFont& font = *reinterpret_cast<SkFont*>(font_data);
227 #endif
228     SkASSERT(extents);
229 
230 #ifdef ENABLE_TEXT_ENHANCE
231     RSRect bounds;
232     SkGlyphID skGlyph = SkTo<SkGlyphID>(hbGlyph);
233 
234     font.GetWidths(&skGlyph, 1, nullptr, &bounds);
235     if (!font.IsSubpixel()) {
236         bounds = RSRect(bounds.RoundOut());
237     }
238 
239     // Skia is y-down but HarfBuzz is y-up.
240     extents->x_bearing = skhb_position(bounds.left_);
241     extents->y_bearing = skhb_position(-bounds.top_);
242     extents->width = skhb_position(bounds.GetWidth());
243     extents->height = skhb_position(-bounds.GetHeight());
244 #else
245     SkRect sk_bounds;
246     SkGlyphID skGlyph = SkTo<SkGlyphID>(hbGlyph);
247 
248     font.getWidths(&skGlyph, 1, nullptr, &sk_bounds);
249     if (!font.isSubpixel()) {
250         sk_bounds.set(sk_bounds.roundOut());
251     }
252 
253     // Skia is y-down but HarfBuzz is y-up.
254     extents->x_bearing = skhb_position(sk_bounds.fLeft);
255     extents->y_bearing = skhb_position(-sk_bounds.fTop);
256     extents->width = skhb_position(sk_bounds.width());
257     extents->height = skhb_position(-sk_bounds.height());
258 #endif
259     return true;
260 }
261 
262 #define SK_HB_VERSION_CHECK(x, y, z) \
263     (HB_VERSION_MAJOR >  (x)) || \
264     (HB_VERSION_MAJOR == (x) && HB_VERSION_MINOR >  (y)) || \
265     (HB_VERSION_MAJOR == (x) && HB_VERSION_MINOR == (y) && HB_VERSION_MICRO >= (z))
266 
267 hb_font_funcs_t* skhb_get_font_funcs() {
268     static hb_font_funcs_t* const funcs = []{
269         // HarfBuzz will use the default (parent) implementation if they aren't set.
270         hb_font_funcs_t* const funcs = hb_font_funcs_create();
271         hb_font_funcs_set_variation_glyph_func(funcs, skhb_glyph, nullptr, nullptr);
272         hb_font_funcs_set_nominal_glyph_func(funcs, skhb_nominal_glyph, nullptr, nullptr);
273 #if SK_HB_VERSION_CHECK(2, 0, 0)
274         hb_font_funcs_set_nominal_glyphs_func(funcs, skhb_nominal_glyphs, nullptr, nullptr);
275 #else
276         sk_ignore_unused_variable(skhb_nominal_glyphs);
277 #endif
278         hb_font_funcs_set_glyph_h_advance_func(funcs, skhb_glyph_h_advance, nullptr, nullptr);
279 #if SK_HB_VERSION_CHECK(1, 8, 6)
280         hb_font_funcs_set_glyph_h_advances_func(funcs, skhb_glyph_h_advances, nullptr, nullptr);
281 #else
282         sk_ignore_unused_variable(skhb_glyph_h_advances);
283 #endif
284         hb_font_funcs_set_glyph_extents_func(funcs, skhb_glyph_extents, nullptr, nullptr);
285         hb_font_funcs_make_immutable(funcs);
286         return funcs;
287     }();
288     SkASSERT(funcs);
289     return funcs;
290 }
291 
292 hb_blob_t* skhb_get_table(hb_face_t* face, hb_tag_t tag, void* user_data) {
293 #ifdef ENABLE_TEXT_ENHANCE
294     RSTypeface& typeface = *reinterpret_cast<RSTypeface*>(user_data);
295 
296     auto size = typeface.GetTableSize(tag);
297     if (!size) {
298         return nullptr;
299     }
300     auto data = std::make_unique<char[]>(size);
301     if (!data) {
302         return nullptr;
303     }
304     auto relTableSize = typeface.GetTableData(tag, 0, size, data.get());
305     if (relTableSize != size) {
306         return nullptr;
307     }
308 
309     auto rawData = data.release();
310     return hb_blob_create(rawData, size,
311                           HB_MEMORY_MODE_READONLY, rawData, [](void* ctx) {
312                               std::unique_ptr<char[]>((char*)ctx);
313                           });
314 #else
315     SkTypeface& typeface = *reinterpret_cast<SkTypeface*>(user_data);
316 
317     auto data = typeface.copyTableData(tag);
318     if (!data) {
319         return nullptr;
320     }
321     SkData* rawData = data.release();
322     return hb_blob_create(reinterpret_cast<char*>(rawData->writable_data()), rawData->size(),
323                           HB_MEMORY_MODE_READONLY, rawData, [](void* ctx) {
324                               SkSafeUnref(((SkData*)ctx));
325                           });
326 #endif
327 }
328 
329 #ifdef ENABLE_TEXT_ENHANCE
330 HBFace create_hb_face(const RSTypeface& typeface) {
331     int index = 0;
332     HBFace face;
333     if (!face) {
334         face.reset(hb_face_create_for_tables(
335             skhb_get_table,
336             const_cast<RSTypeface*>(std::make_unique<RSTypeface>(typeface).release()),
337             [](void* user_data){ std::unique_ptr<RSTypeface>(reinterpret_cast<RSTypeface*>(user_data)); }));
338         hb_face_set_index(face.get(), (unsigned)index);
339     }
340     SkASSERT(face);
341     if (!face) {
342         return nullptr;
343     }
344     hb_face_set_upem(face.get(), typeface.GetUnitsPerEm());
345 
346     return face;
347 }
348 #else
349 HBBlob stream_to_blob(std::unique_ptr<SkStreamAsset> asset) {
350     size_t size = asset->getLength();
351     HBBlob blob;
352     if (const void* base = asset->getMemoryBase()) {
353         blob.reset(hb_blob_create((const char*)base, SkToUInt(size),
354                                   HB_MEMORY_MODE_READONLY, asset.release(),
355                                   [](void* p) { delete (SkStreamAsset*)p; }));
356     } else {
357         // SkDebugf("Extra SkStreamAsset copy\n");
358         void* ptr = size ? sk_malloc_throw(size) : nullptr;
359         asset->read(ptr, size);
360         blob.reset(hb_blob_create((char*)ptr, SkToUInt(size),
361                                   HB_MEMORY_MODE_READONLY, ptr, sk_free));
362     }
363     SkASSERT(blob);
364     hb_blob_make_immutable(blob.get());
365     return blob;
366 }
367 
368 SkDEBUGCODE(static hb_user_data_key_t gDataIdKey;)
369 
370 HBFace create_hb_face(const SkTypeface& typeface) {
371     int index = 0;
372     std::unique_ptr<SkStreamAsset> typefaceAsset = typeface.openExistingStream(&index);
373     HBFace face;
374     if (typefaceAsset && typefaceAsset->getMemoryBase()) {
375         HBBlob blob(stream_to_blob(std::move(typefaceAsset)));
376         // hb_face_create always succeeds. Check that the format is minimally recognized first.
377         // hb_face_create_for_tables may still create a working hb_face.
378         // See https://github.com/harfbuzz/harfbuzz/issues/248 .
379         unsigned int num_hb_faces = hb_face_count(blob.get());
380         if (0 < num_hb_faces && (unsigned)index < num_hb_faces) {
381             face.reset(hb_face_create(blob.get(), (unsigned)index));
382             // Check the number of glyphs as a basic sanitization step.
383             if (face && hb_face_get_glyph_count(face.get()) == 0) {
384                 face.reset();
385             }
386         }
387     }
388     if (!face) {
389         face.reset(hb_face_create_for_tables(
390             skhb_get_table,
391             const_cast<SkTypeface*>(SkRef(&typeface)),
392             [](void* user_data){ SkSafeUnref(reinterpret_cast<SkTypeface*>(user_data)); }));
393         hb_face_set_index(face.get(), (unsigned)index);
394     }
395     SkASSERT(face);
396     if (!face) {
397         return nullptr;
398     }
399     hb_face_set_upem(face.get(), typeface.getUnitsPerEm());
400 
401     SkDEBUGCODE(
402         hb_face_set_user_data(face.get(), &gDataIdKey, const_cast<SkTypeface*>(&typeface),
403                               nullptr, false);
404     )
405 
406     return face;
407 }
408 #endif
409 
410 #ifdef ENABLE_TEXT_ENHANCE
411 HBFont create_typeface_hb_font(const RSTypeface& typeface) {
412 #else
413 HBFont create_typeface_hb_font(const SkTypeface& typeface) {
414 #endif
415     HBFace face(create_hb_face(typeface));
416     if (!face) {
417         return nullptr;
418     }
419 
420     HBFont otFont(hb_font_create(face.get()));
421     SkASSERT(otFont);
422     if (!otFont) {
423         return nullptr;
424     }
425     hb_ot_font_set_funcs(otFont.get());
426 #ifndef ENABLE_TEXT_ENHANCE
427     int axis_count = typeface.getVariationDesignPosition(nullptr, 0);
428     if (axis_count > 0) {
429         AutoSTMalloc<4, SkFontArguments::VariationPosition::Coordinate> axis_values(axis_count);
430         if (typeface.getVariationDesignPosition(axis_values, axis_count) == axis_count) {
431             hb_font_set_variations(otFont.get(),
432                                    reinterpret_cast<hb_variation_t*>(axis_values.get()),
433                                    axis_count);
434         }
435     }
436 #endif
437 
438     return otFont;
439 }
440 
441 #ifdef ENABLE_TEXT_ENHANCE
442 HBFont create_sub_hb_font(const RSFont& font, const HBFont& typefaceFont) {
443     // Creating a sub font means that non-available functions
444     // are found from the parent.
445     HBFont skFont(hb_font_create_sub_font(typefaceFont.get()));
446     hb_font_set_funcs(skFont.get(), skhb_get_font_funcs(),
447                       reinterpret_cast<void *>(std::make_unique<RSFont>(font).release()),
448                       [](void* user_data){ std::unique_ptr<RSFont>(reinterpret_cast<RSFont*>(user_data)); });
449     int scale = skhb_position(font.GetSize());
450     hb_font_set_scale(skFont.get(), scale, scale);
451 
452     return skFont;
453 }
454 #else
455 HBFont create_sub_hb_font(const SkFont& font, const HBFont& typefaceFont) {
456     SkDEBUGCODE(
457         hb_face_t* face = hb_font_get_face(typefaceFont.get());
458         void* dataId = hb_face_get_user_data(face, &gDataIdKey);
459         SkASSERT(dataId == font.getTypeface());
460     )
461 
462     // Creating a sub font means that non-available functions
463     // are found from the parent.
464     HBFont skFont(hb_font_create_sub_font(typefaceFont.get()));
465     hb_font_set_funcs(skFont.get(), skhb_get_font_funcs(),
466                       reinterpret_cast<void *>(new SkFont(font)),
467                       [](void* user_data){ delete reinterpret_cast<SkFont*>(user_data); });
468     int scale = skhb_position(font.getSize());
469     hb_font_set_scale(skFont.get(), scale, scale);
470 
471     return skFont;
472 }
473 #endif
474 
475 /** Replaces invalid utf-8 sequences with REPLACEMENT CHARACTER U+FFFD. */
476 static inline SkUnichar utf8_next(const char** ptr, const char* end) {
477     SkUnichar val = SkUTF::NextUTF8(ptr, end);
478     return val < 0 ? 0xFFFD : val;
479 }
480 
481 class SkUnicodeHbScriptRunIterator final: public SkShaper::ScriptRunIterator {
482 public:
483     SkUnicodeHbScriptRunIterator(const char* utf8,
484                                  size_t utf8Bytes,
485                                  hb_script_t defaultScript)
486             : fCurrent(utf8)
487             , fBegin(utf8)
488             , fEnd(fCurrent + utf8Bytes)
489             , fCurrentScript(defaultScript) {}
490     hb_script_t hb_script_for_unichar(SkUnichar u) {
491          return hb_unicode_script(hb_unicode_funcs_get_default(), u);
492     }
493     void consume() override {
494         SkASSERT(fCurrent < fEnd);
495         SkUnichar u = utf8_next(&fCurrent, fEnd);
496         fCurrentScript = hb_script_for_unichar(u);
497         while (fCurrent < fEnd) {
498             const char* prev = fCurrent;
499             u = utf8_next(&fCurrent, fEnd);
500             const hb_script_t script = hb_script_for_unichar(u);
501             if (script != fCurrentScript) {
502                 if (fCurrentScript == HB_SCRIPT_INHERITED || fCurrentScript == HB_SCRIPT_COMMON) {
503                     fCurrentScript = script;
504                 } else if (script == HB_SCRIPT_INHERITED || script == HB_SCRIPT_COMMON) {
505                     continue;
506                 } else {
507                     fCurrent = prev;
508                     break;
509                 }
510             }
511         }
512         if (fCurrentScript == HB_SCRIPT_INHERITED) {
513             fCurrentScript = HB_SCRIPT_COMMON;
514         }
515     }
516     size_t endOfCurrentRun() const override {
517         return fCurrent - fBegin;
518     }
519     bool atEnd() const override {
520         return fCurrent == fEnd;
521     }
522 
523     SkFourByteTag currentScript() const override {
524         return SkSetFourByteTag(HB_UNTAG(fCurrentScript));
525     }
526 private:
527     char const * fCurrent;
528     char const * const fBegin;
529     char const * const fEnd;
530     hb_script_t fCurrentScript;
531 };
532 
533 class RunIteratorQueue {
534 public:
535     void insert(SkShaper::RunIterator* runIterator, int priority) {
536         fEntries.insert({runIterator, priority});
537     }
538 
539     bool advanceRuns() {
540         const SkShaper::RunIterator* leastRun = fEntries.peek().runIterator;
541         if (leastRun->atEnd()) {
542             SkASSERT(this->allRunsAreAtEnd());
543             return false;
544         }
545         const size_t leastEnd = leastRun->endOfCurrentRun();
546         SkShaper::RunIterator* currentRun = nullptr;
547         SkDEBUGCODE(size_t previousEndOfCurrentRun);
548         while ((currentRun = fEntries.peek().runIterator)->endOfCurrentRun() <= leastEnd) {
549             int priority = fEntries.peek().priority;
550             fEntries.pop();
551             SkDEBUGCODE(previousEndOfCurrentRun = currentRun->endOfCurrentRun());
552             currentRun->consume();
553             SkASSERT(previousEndOfCurrentRun < currentRun->endOfCurrentRun());
554             fEntries.insert({currentRun, priority});
555         }
556         return true;
557     }
558 
559     size_t endOfCurrentRun() const {
560         return fEntries.peek().runIterator->endOfCurrentRun();
561     }
562 
563 private:
564     bool allRunsAreAtEnd() const {
565         for (int i = 0; i < fEntries.count(); ++i) {
566             if (!fEntries.at(i).runIterator->atEnd()) {
567                 return false;
568             }
569         }
570         return true;
571     }
572 
573     struct Entry {
574         SkShaper::RunIterator* runIterator;
575         int priority;
576     };
577     static bool CompareEntry(Entry const& a, Entry const& b) {
578         size_t aEnd = a.runIterator->endOfCurrentRun();
579         size_t bEnd = b.runIterator->endOfCurrentRun();
580         return aEnd  < bEnd || (aEnd == bEnd && a.priority < b.priority);
581     }
582     SkTDPQueue<Entry, CompareEntry> fEntries;
583 };
584 
585 struct ShapedGlyph {
586     SkGlyphID fID;
587     uint32_t fCluster;
588     SkPoint fOffset;
589     SkVector fAdvance;
590     bool fMayLineBreakBefore;
591     bool fMustLineBreakBefore;
592     bool fHasVisual;
593     bool fGraphemeBreakBefore;
594     bool fUnsafeToBreak;
595 };
596 
597 #ifdef ENABLE_TEXT_ENHANCE
598 struct ShapedRun {
599     ShapedRun(SkShaper::RunHandler::Range utf8Range, const RSFont& font, SkBidiIterator::Level level,
600               std::unique_ptr<ShapedGlyph[]> glyphs, size_t numGlyphs, SkVector advance = {0, 0})
601         : fUtf8Range(utf8Range), fFont(font), fLevel(level),
602             fGlyphs(std::move(glyphs)), fNumGlyphs(numGlyphs), fAdvance(advance)
603     {}
604 
605     SkShaper::RunHandler::Range fUtf8Range;
606     RSFont fFont;
607     SkBidiIterator::Level fLevel;
608     std::unique_ptr<ShapedGlyph[]> fGlyphs;
609     size_t fNumGlyphs;
610     SkVector fAdvance;
611 };
612 #else
613 struct ShapedRun {
614     ShapedRun(SkShaper::RunHandler::Range utf8Range, const SkFont& font, SkBidiIterator::Level level,
615               std::unique_ptr<ShapedGlyph[]> glyphs, size_t numGlyphs, SkVector advance = {0, 0})
616         : fUtf8Range(utf8Range), fFont(font), fLevel(level)
617         , fGlyphs(std::move(glyphs)), fNumGlyphs(numGlyphs), fAdvance(advance)
618     {}
619 
620     SkShaper::RunHandler::Range fUtf8Range;
621     SkFont fFont;
622     SkBidiIterator::Level fLevel;
623     std::unique_ptr<ShapedGlyph[]> fGlyphs;
624     size_t fNumGlyphs;
625     SkVector fAdvance;
626 
627     static_assert(::sk_is_trivially_relocatable<decltype(fUtf8Range)>::value);
628     static_assert(::sk_is_trivially_relocatable<decltype(fFont)>::value);
629     static_assert(::sk_is_trivially_relocatable<decltype(fLevel)>::value);
630     static_assert(::sk_is_trivially_relocatable<decltype(fGlyphs)>::value);
631     static_assert(::sk_is_trivially_relocatable<decltype(fAdvance)>::value);
632 
633     using sk_is_trivially_relocatable = std::true_type;
634 };
635 #endif
636 struct ShapedLine {
637     TArray<ShapedRun> runs;
638     SkVector fAdvance = { 0, 0 };
639 };
640 
641 constexpr bool is_LTR(SkBidiIterator::Level level) {
642     return (level & 1) == 0;
643 }
644 
645 void append(SkShaper::RunHandler* handler, const SkShaper::RunHandler::RunInfo& runInfo,
646                    const ShapedRun& run, size_t startGlyphIndex, size_t endGlyphIndex) {
647     SkASSERT(startGlyphIndex <= endGlyphIndex);
648     const size_t glyphLen = endGlyphIndex - startGlyphIndex;
649 
650     const auto buffer = handler->runBuffer(runInfo);
651     SkASSERT(buffer.glyphs);
652     SkASSERT(buffer.positions);
653 
654     SkVector advance = {0,0};
655     for (size_t i = 0; i < glyphLen; i++) {
656         // Glyphs are in logical order, but output ltr since PDF readers seem to expect that.
657         const ShapedGlyph& glyph = run.fGlyphs[is_LTR(run.fLevel) ? startGlyphIndex + i
658                                                                   : endGlyphIndex - 1 - i];
659         buffer.glyphs[i] = glyph.fID;
660         if (buffer.offsets) {
661             buffer.positions[i] = advance + buffer.point;
662             buffer.offsets[i] = glyph.fOffset;
663         } else {
664             buffer.positions[i] = advance + buffer.point + glyph.fOffset;
665         }
666         if (buffer.clusters) {
667 #ifdef ENABLE_TEXT_ENHANCE
668             // Specail handle for Rtl language's cluster index overall offset
669             size_t clusterUpdatePos = is_LTR(run.fLevel) ? i : i + 1;
670             buffer.clusters[clusterUpdatePos] = glyph.fCluster;
671 #else
672             buffer.clusters[i] = glyph.fCluster;
673 #endif
674         }
675 #ifdef ENABLE_TEXT_ENHANCE
676         if (buffer.advances) {
677             buffer.advances[i] = glyph.fAdvance;
678         }
679 #endif
680         advance += glyph.fAdvance;
681     }
682     handler->commitRunBuffer(runInfo);
683 }
684 
685 void emit(SkUnicode* unicode, const ShapedLine& line, SkShaper::RunHandler* handler) {
686     // Reorder the runs and glyphs per line and write them out.
687     handler->beginLine();
688 
689     int numRuns = line.runs.size();
690     AutoSTMalloc<4, SkBidiIterator::Level> runLevels(numRuns);
691     for (int i = 0; i < numRuns; ++i) {
692         runLevels[i] = line.runs[i].fLevel;
693     }
694     AutoSTMalloc<4, int32_t> logicalFromVisual(numRuns);
695     unicode->reorderVisual(runLevels, numRuns, logicalFromVisual);
696 
697     for (int i = 0; i < numRuns; ++i) {
698         int logicalIndex = logicalFromVisual[i];
699 
700         const auto& run = line.runs[logicalIndex];
701         const SkShaper::RunHandler::RunInfo info = {
702             run.fFont,
703             run.fLevel,
704             run.fAdvance,
705             run.fNumGlyphs,
706             run.fUtf8Range
707         };
708         handler->runInfo(info);
709     }
710     handler->commitRunInfo();
711     for (int i = 0; i < numRuns; ++i) {
712         int logicalIndex = logicalFromVisual[i];
713 
714         const auto& run = line.runs[logicalIndex];
715         const SkShaper::RunHandler::RunInfo info = {
716             run.fFont,
717             run.fLevel,
718             run.fAdvance,
719             run.fNumGlyphs,
720             run.fUtf8Range
721         };
722         append(handler, info, run, 0, run.fNumGlyphs);
723     }
724 
725     handler->commitLine();
726 }
727 
728 struct ShapedRunGlyphIterator {
729     ShapedRunGlyphIterator(const TArray<ShapedRun>& origRuns)
730         : fRuns(&origRuns), fRunIndex(0), fGlyphIndex(0)
731     { }
732 
733     ShapedRunGlyphIterator(const ShapedRunGlyphIterator& that) = default;
734     ShapedRunGlyphIterator& operator=(const ShapedRunGlyphIterator& that) = default;
735     bool operator==(const ShapedRunGlyphIterator& that) const {
736         return fRuns == that.fRuns &&
737                fRunIndex == that.fRunIndex &&
738                fGlyphIndex == that.fGlyphIndex;
739     }
740     bool operator!=(const ShapedRunGlyphIterator& that) const {
741         return fRuns != that.fRuns ||
742                fRunIndex != that.fRunIndex ||
743                fGlyphIndex != that.fGlyphIndex;
744     }
745 
746     ShapedGlyph* next() {
747         const TArray<ShapedRun>& runs = *fRuns;
748         SkASSERT(fRunIndex < runs.size());
749         SkASSERT(fGlyphIndex < runs[fRunIndex].fNumGlyphs);
750 
751         ++fGlyphIndex;
752         if (fGlyphIndex == runs[fRunIndex].fNumGlyphs) {
753             fGlyphIndex = 0;
754             ++fRunIndex;
755 #ifdef ENABLE_TEXT_ENHANCE
756             if (static_cast<size_t>(fRunIndex) >= runs.size()) {
757 #else
758             if (fRunIndex >= runs.size()) {
759 #endif
760                 return nullptr;
761             }
762         }
763         return &runs[fRunIndex].fGlyphs[fGlyphIndex];
764     }
765 
766     ShapedGlyph* current() {
767         const TArray<ShapedRun>& runs = *fRuns;
768 #ifdef ENABLE_TEXT_ENHANCE
769         if (static_cast<size_t>(fRunIndex) >= runs.size()) {
770 #else
771         if (fRunIndex >= runs.size()) {
772 #endif
773             return nullptr;
774         }
775         return &runs[fRunIndex].fGlyphs[fGlyphIndex];
776     }
777 
778     const TArray<ShapedRun>* fRuns;
779     int fRunIndex;
780     size_t fGlyphIndex;
781 };
782 
783 class ShaperHarfBuzz : public SkShaper {
784 public:
785     ShaperHarfBuzz(sk_sp<SkUnicode>,
786                    HBBuffer,
787 #ifdef ENABLE_TEXT_ENHANCE
788                    std::shared_ptr<RSFontMgr>);
789 #else
790                    sk_sp<SkFontMgr>);
791 #endif
792 
793 protected:
794     sk_sp<SkUnicode> fUnicode;
795 
796     ShapedRun shape(const char* utf8, size_t utf8Bytes,
797                     const char* utf8Start,
798                     const char* utf8End,
799                     const BiDiRunIterator&,
800                     const LanguageRunIterator&,
801                     const ScriptRunIterator&,
802                     const FontRunIterator&,
803                     const Feature*, size_t featuresSize) const;
804 private:
805 #ifdef ENABLE_TEXT_ENHANCE
806     const std::shared_ptr<RSFontMgr> fFontMgr;
807 #else
808     const sk_sp<SkFontMgr> fFontMgr; // for fallback
809 #endif
810     HBBuffer               fBuffer;
811     hb_language_t          fUndefinedLanguage;
812 
813 #if !defined(SK_DISABLE_LEGACY_SKSHAPER_FUNCTIONS)
814     void shape(const char* utf8, size_t utf8Bytes,
815 #ifdef ENABLE_TEXT_ENHANCE
816                const RSFont&,
817 #else
818                const SkFont&,
819 #endif
820                bool leftToRight,
821                SkScalar width,
822                RunHandler*) const override;
823 
824     void shape(const char* utf8Text, size_t textBytes,
825                FontRunIterator&,
826                BiDiRunIterator&,
827                ScriptRunIterator&,
828                LanguageRunIterator&,
829                SkScalar width,
830                RunHandler*) const override;
831 #endif
832 
833     void shape(const char* utf8Text, size_t textBytes,
834                FontRunIterator&,
835                BiDiRunIterator&,
836                ScriptRunIterator&,
837                LanguageRunIterator&,
838                const Feature*, size_t featuresSize,
839                SkScalar width,
840                RunHandler*) const override;
841 
842     virtual void wrap(char const * const utf8, size_t utf8Bytes,
843                       const BiDiRunIterator&,
844                       const LanguageRunIterator&,
845                       const ScriptRunIterator&,
846                       const FontRunIterator&,
847                       RunIteratorQueue& runSegmenter,
848                       const Feature*, size_t featuresSize,
849                       SkScalar width,
850                       RunHandler*) const = 0;
851 };
852 
853 class ShaperDrivenWrapper : public ShaperHarfBuzz {
854 public:
855     using ShaperHarfBuzz::ShaperHarfBuzz;
856 private:
857     void wrap(char const * const utf8, size_t utf8Bytes,
858               const BiDiRunIterator&,
859               const LanguageRunIterator&,
860               const ScriptRunIterator&,
861               const FontRunIterator&,
862               RunIteratorQueue& runSegmenter,
863               const Feature*, size_t featuresSize,
864               SkScalar width,
865               RunHandler*) const override;
866 };
867 
868 class ShapeThenWrap : public ShaperHarfBuzz {
869 public:
870     using ShaperHarfBuzz::ShaperHarfBuzz;
871 private:
872     void wrap(char const * const utf8, size_t utf8Bytes,
873               const BiDiRunIterator&,
874               const LanguageRunIterator&,
875               const ScriptRunIterator&,
876               const FontRunIterator&,
877               RunIteratorQueue& runSegmenter,
878               const Feature*, size_t featuresSize,
879               SkScalar width,
880               RunHandler*) const override;
881 };
882 
883 class ShapeDontWrapOrReorder : public ShaperHarfBuzz {
884 public:
885     using ShaperHarfBuzz::ShaperHarfBuzz;
886 private:
887     void wrap(char const * const utf8, size_t utf8Bytes,
888               const BiDiRunIterator&,
889               const LanguageRunIterator&,
890               const ScriptRunIterator&,
891               const FontRunIterator&,
892               RunIteratorQueue& runSegmenter,
893               const Feature*, size_t featuresSize,
894               SkScalar width,
895               RunHandler*) const override;
896 };
897 
898 
899 ShaperHarfBuzz::ShaperHarfBuzz(sk_sp<SkUnicode> unicode,
900 #ifdef ENABLE_TEXT_ENHANCE
901                                HBBuffer buffer, std::shared_ptr<RSFontMgr> fallback) : fUnicode(unicode),
902                                fFontMgr(fallback ? std::move(fallback) : RSFontMgr::CreateDefaultFontMgr()),
903 #else
904                                HBBuffer buffer, sk_sp<SkFontMgr> fallback) : fUnicode(unicode),
905                                fFontMgr(fallback ? std::move(fallback) : SkFontMgr::RefEmpty()),
906 #endif
907                                fBuffer(std::move(buffer)),
908                                fUndefinedLanguage(hb_language_from_string("und", -1))
909 {
910 #if defined(SK_DISABLE_LEGACY_SKSHAPER_FUNCTIONS)
911     SkASSERT(fUnicode);
912 #endif
913 }
914 
915 #if !defined(SK_DISABLE_LEGACY_SKSHAPER_FUNCTIONS)
916 void ShaperHarfBuzz::shape(const char* utf8,
917                            size_t utf8Bytes,
918 #ifdef ENABLE_TEXT_ENHANCE
919                            const RSFont& srcFont,
920 #else
921                            const SkFont& srcFont,
922 #endif
923                            bool leftToRight,
924                            SkScalar width,
925                            RunHandler* handler) const {
926     SkBidiIterator::Level defaultLevel = leftToRight ? SkBidiIterator::kLTR : SkBidiIterator::kRTL;
927     std::unique_ptr<BiDiRunIterator> bidi(
928             SkShapers::unicode::BidiRunIterator(fUnicode, utf8, utf8Bytes, defaultLevel));
929 
930     if (!bidi) {
931         return;
932     }
933 
934     std::unique_ptr<LanguageRunIterator> language(MakeStdLanguageRunIterator(utf8, utf8Bytes));
935     if (!language) {
936         return;
937     }
938 
939     std::unique_ptr<ScriptRunIterator> script(SkShapers::HB::ScriptRunIterator(utf8, utf8Bytes));
940     if (!script) {
941         return;
942     }
943 
944     std::unique_ptr<FontRunIterator> font(
945                 MakeFontMgrRunIterator(utf8, utf8Bytes, srcFont, fFontMgr));
946     if (!font) {
947         return;
948     }
949 
950     this->shape(utf8, utf8Bytes, *font, *bidi, *script, *language, width, handler);
951 }
952 
953 void ShaperHarfBuzz::shape(const char* utf8,
954                            size_t utf8Bytes,
955                            FontRunIterator& font,
956                            BiDiRunIterator& bidi,
957                            ScriptRunIterator& script,
958                            LanguageRunIterator& language,
959                            SkScalar width,
960                            RunHandler* handler) const {
961     this->shape(utf8, utf8Bytes, font, bidi, script, language, nullptr, 0, width, handler);
962 }
963 #endif  // !defined(SK_DISABLE_LEGACY_SKSHAPER_FUNCTIONS)
964 
965 void ShaperHarfBuzz::shape(const char* utf8,
966                            size_t utf8Bytes,
967                            FontRunIterator& font,
968                            BiDiRunIterator& bidi,
969                            ScriptRunIterator& script,
970                            LanguageRunIterator& language,
971                            const Feature* features,
972                            size_t featuresSize,
973                            SkScalar width,
974                            RunHandler* handler) const {
975     SkASSERT(handler);
976     RunIteratorQueue runSegmenter;
977     runSegmenter.insert(&font,     3); // The font iterator is always run last in case of tie.
978     runSegmenter.insert(&bidi,     2);
979     runSegmenter.insert(&script,   1);
980     runSegmenter.insert(&language, 0);
981 
982     this->wrap(utf8, utf8Bytes, bidi, language, script, font, runSegmenter,
983                features, featuresSize, width, handler);
984 }
985 
986 void ShaperDrivenWrapper::wrap(char const * const utf8, size_t utf8Bytes,
987                                const BiDiRunIterator& bidi,
988                                const LanguageRunIterator& language,
989                                const ScriptRunIterator& script,
990                                const FontRunIterator& font,
991                                RunIteratorQueue& runSegmenter,
992                                const Feature* features, size_t featuresSize,
993                                SkScalar width,
994                                RunHandler* handler) const
995 {
996     ShapedLine line;
997 
998     const char* utf8Start = nullptr;
999     const char* utf8End = utf8;
1000     SkUnicodeBreak lineBreakIterator;
1001     SkString currentLanguage;
1002     while (runSegmenter.advanceRuns()) {  // For each item
1003         utf8Start = utf8End;
1004         utf8End = utf8 + runSegmenter.endOfCurrentRun();
1005 
1006 #ifdef ENABLE_TEXT_ENHANCE
1007         ShapedRun model(RunHandler::Range(), RSFont(), 0, nullptr, 0);
1008 #else
1009         ShapedRun model(RunHandler::Range(), SkFont(), 0, nullptr, 0);
1010 #endif
1011         bool modelNeedsRegenerated = true;
1012         int modelGlyphOffset = 0;
1013 
1014         struct TextProps {
1015             int glyphLen = 0;
1016             SkVector advance = {0, 0};
1017         };
1018         // map from character position to [safe to break, glyph position, advance]
1019         std::unique_ptr<TextProps[]> modelText;
1020         int modelTextOffset = 0;
1021         SkVector modelAdvanceOffset = {0, 0};
1022 
1023         while (utf8Start < utf8End) {  // While there are still code points left in this item
1024             size_t utf8runLength = utf8End - utf8Start;
1025             if (modelNeedsRegenerated) {
1026                 model = shape(utf8, utf8Bytes,
1027                               utf8Start, utf8End,
1028                               bidi, language, script, font,
1029                               features, featuresSize);
1030                 modelGlyphOffset = 0;
1031 
1032                 SkVector advance = {0, 0};
1033                 modelText = std::make_unique<TextProps[]>(utf8runLength + 1);
1034                 size_t modelStartCluster = utf8Start - utf8;
1035                 size_t previousCluster = 0;
1036                 for (size_t i = 0; i < model.fNumGlyphs; ++i) {
1037                     SkASSERT(modelStartCluster <= model.fGlyphs[i].fCluster);
1038                     SkASSERT(                     model.fGlyphs[i].fCluster < (size_t)(utf8End - utf8));
1039                     if (!model.fGlyphs[i].fUnsafeToBreak) {
1040                         // Store up to the first glyph in the cluster.
1041                         size_t currentCluster = model.fGlyphs[i].fCluster - modelStartCluster;
1042                         if (previousCluster != currentCluster) {
1043                             previousCluster  = currentCluster;
1044                             modelText[currentCluster].glyphLen = i;
1045                             modelText[currentCluster].advance = advance;
1046                         }
1047                     }
1048                     advance += model.fGlyphs[i].fAdvance;
1049                 }
1050                 // Assume it is always safe to break after the end of an item
1051                 modelText[utf8runLength].glyphLen = model.fNumGlyphs;
1052                 modelText[utf8runLength].advance = model.fAdvance;
1053                 modelTextOffset = 0;
1054                 modelAdvanceOffset = {0, 0};
1055                 modelNeedsRegenerated = false;
1056             }
1057 
1058             // TODO: break iterator per item, but just reset position if needed?
1059             // Maybe break iterator with model?
1060             if (!lineBreakIterator || !currentLanguage.equals(language.currentLanguage())) {
1061                 currentLanguage = language.currentLanguage();
1062                 lineBreakIterator = fUnicode->makeBreakIterator(currentLanguage.c_str(),
1063                                                                 SkUnicode::BreakType::kLines);
1064                 if (!lineBreakIterator) {
1065                     return;
1066                 }
1067             }
1068             if (!lineBreakIterator->setText(utf8Start, utf8runLength)) {
1069                 return;
1070             }
1071             SkBreakIterator& breakIterator = *lineBreakIterator;
1072 
1073 #ifdef ENABLE_TEXT_ENHANCE
1074             ShapedRun best(RunHandler::Range(), RSFont(), 0, nullptr, 0,
1075                            { SK_ScalarNegativeInfinity, SK_ScalarNegativeInfinity });
1076 #else
1077             ShapedRun best(RunHandler::Range(), SkFont(), 0, nullptr, 0,
1078                            { SK_ScalarNegativeInfinity, SK_ScalarNegativeInfinity });
1079 #endif
1080             bool bestIsInvalid = true;
1081             bool bestUsesModelForGlyphs = false;
1082             SkScalar widthLeft = width - line.fAdvance.fX;
1083 
1084             for (int32_t breakIteratorCurrent = breakIterator.next();
1085                  !breakIterator.isDone();
1086                  breakIteratorCurrent = breakIterator.next())
1087             {
1088                 // TODO: if past a safe to break, future safe to break will be at least as long
1089 
1090                 // TODO: adjust breakIteratorCurrent by ignorable whitespace
1091                 bool candidateUsesModelForGlyphs = false;
1092                 ShapedRun candidate = [&](const TextProps& props){
1093                     if (props.glyphLen) {
1094                         candidateUsesModelForGlyphs = true;
1095                         return ShapedRun(RunHandler::Range(utf8Start - utf8, breakIteratorCurrent),
1096                                          font.currentFont(), bidi.currentLevel(),
1097                                          std::unique_ptr<ShapedGlyph[]>(),
1098                                          props.glyphLen - modelGlyphOffset,
1099                                          props.advance - modelAdvanceOffset);
1100                     } else {
1101                         return shape(utf8, utf8Bytes,
1102                                      utf8Start, utf8Start + breakIteratorCurrent,
1103                                      bidi, language, script, font,
1104                                      features, featuresSize);
1105                     }
1106                 }(modelText[breakIteratorCurrent + modelTextOffset]);
1107                 auto score = [widthLeft](const ShapedRun& run) -> SkScalar {
1108                     if (run.fAdvance.fX < widthLeft) {
1109                         return run.fUtf8Range.size();
1110                     } else {
1111                         return widthLeft - run.fAdvance.fX;
1112                     }
1113                 };
1114                 if (bestIsInvalid || score(best) < score(candidate)) {
1115                     best = std::move(candidate);
1116                     bestIsInvalid = false;
1117                     bestUsesModelForGlyphs = candidateUsesModelForGlyphs;
1118                 }
1119             }
1120 
1121             // If nothing fit (best score is negative) and the line is not empty
1122             if (width < line.fAdvance.fX + best.fAdvance.fX && !line.runs.empty()) {
1123                 emit(fUnicode.get(), line, handler);
1124                 line.runs.clear();
1125                 line.fAdvance = {0, 0};
1126             } else {
1127                 if (bestUsesModelForGlyphs) {
1128                     best.fGlyphs = std::make_unique<ShapedGlyph[]>(best.fNumGlyphs);
1129                     memcpy(best.fGlyphs.get(), model.fGlyphs.get() + modelGlyphOffset,
1130                            best.fNumGlyphs * sizeof(ShapedGlyph));
1131                     modelGlyphOffset += best.fNumGlyphs;
1132                     modelTextOffset += best.fUtf8Range.size();
1133                     modelAdvanceOffset += best.fAdvance;
1134                 } else {
1135                     modelNeedsRegenerated = true;
1136                 }
1137                 utf8Start += best.fUtf8Range.size();
1138                 line.fAdvance += best.fAdvance;
1139                 line.runs.emplace_back(std::move(best));
1140 
1141                 // If item broken, emit line (prevent remainder from accidentally fitting)
1142                 if (utf8Start != utf8End) {
1143                     emit(fUnicode.get(), line, handler);
1144                     line.runs.clear();
1145                     line.fAdvance = {0, 0};
1146                 }
1147             }
1148         }
1149     }
1150     emit(fUnicode.get(), line, handler);
1151 }
1152 
1153 void ShapeThenWrap::wrap(char const * const utf8, size_t utf8Bytes,
1154                          const BiDiRunIterator& bidi,
1155                          const LanguageRunIterator& language,
1156                          const ScriptRunIterator& script,
1157                          const FontRunIterator& font,
1158                          RunIteratorQueue& runSegmenter,
1159                          const Feature* features, size_t featuresSize,
1160                          SkScalar width,
1161                          RunHandler* handler) const
1162 {
1163     TArray<ShapedRun> runs;
1164 {
1165     SkString currentLanguage;
1166     SkUnicodeBreak lineBreakIterator;
1167     SkUnicodeBreak graphemeBreakIterator;
1168     bool needIteratorInit = true;
1169     const char* utf8Start = nullptr;
1170     const char* utf8End = utf8;
1171     while (runSegmenter.advanceRuns()) {
1172         utf8Start = utf8End;
1173         utf8End = utf8 + runSegmenter.endOfCurrentRun();
1174 
1175         runs.emplace_back(shape(utf8, utf8Bytes,
1176                                 utf8Start, utf8End,
1177                                 bidi, language, script, font,
1178                                 features, featuresSize));
1179         ShapedRun& run = runs.back();
1180 
1181         if (needIteratorInit || !currentLanguage.equals(language.currentLanguage())) {
1182             currentLanguage = language.currentLanguage();
1183             lineBreakIterator = fUnicode->makeBreakIterator(currentLanguage.c_str(),
1184                                                             SkUnicode::BreakType::kLines);
1185             if (!lineBreakIterator) {
1186                 return;
1187             }
1188             graphemeBreakIterator = fUnicode->makeBreakIterator(currentLanguage.c_str(),
1189                                                                 SkUnicode::BreakType::kGraphemes);
1190             if (!graphemeBreakIterator) {
1191                 return;
1192             }
1193             needIteratorInit = false;
1194         }
1195         size_t utf8runLength = utf8End - utf8Start;
1196         if (!lineBreakIterator->setText(utf8Start, utf8runLength)) {
1197             return;
1198         }
1199         if (!graphemeBreakIterator->setText(utf8Start, utf8runLength)) {
1200             return;
1201         }
1202 
1203         uint32_t previousCluster = 0xFFFFFFFF;
1204         for (size_t i = 0; i < run.fNumGlyphs; ++i) {
1205             ShapedGlyph& glyph = run.fGlyphs[i];
1206             int32_t glyphCluster = glyph.fCluster;
1207 
1208             int32_t lineBreakIteratorCurrent = lineBreakIterator->current();
1209             while (!lineBreakIterator->isDone() && lineBreakIteratorCurrent < glyphCluster)
1210             {
1211                 lineBreakIteratorCurrent = lineBreakIterator->next();
1212             }
1213             glyph.fMayLineBreakBefore = glyph.fCluster != previousCluster &&
1214                                         lineBreakIteratorCurrent == glyphCluster;
1215 
1216             int32_t graphemeBreakIteratorCurrent = graphemeBreakIterator->current();
1217             while (!graphemeBreakIterator->isDone() && graphemeBreakIteratorCurrent < glyphCluster)
1218             {
1219                 graphemeBreakIteratorCurrent = graphemeBreakIterator->next();
1220             }
1221             glyph.fGraphemeBreakBefore = glyph.fCluster != previousCluster &&
1222                                          graphemeBreakIteratorCurrent == glyphCluster;
1223 
1224             previousCluster = glyph.fCluster;
1225         }
1226     }
1227 }
1228 
1229 // Iterate over the glyphs in logical order to find potential line lengths.
1230 {
1231     /** The position of the beginning of the line. */
1232     ShapedRunGlyphIterator beginning(runs);
1233 
1234     /** The position of the candidate line break. */
1235     ShapedRunGlyphIterator candidateLineBreak(runs);
1236     SkScalar candidateLineBreakWidth = 0;
1237 
1238     /** The position of the candidate grapheme break. */
1239     ShapedRunGlyphIterator candidateGraphemeBreak(runs);
1240     SkScalar candidateGraphemeBreakWidth = 0;
1241 
1242     /** The position of the current location. */
1243     ShapedRunGlyphIterator current(runs);
1244     SkScalar currentWidth = 0;
1245     while (ShapedGlyph* glyph = current.current()) {
1246         // 'Break' at graphemes until a line boundary, then only at line boundaries.
1247         // Only break at graphemes if no line boundary is valid.
1248         if (current != beginning) {
1249             if (glyph->fGraphemeBreakBefore || glyph->fMayLineBreakBefore) {
1250                 // TODO: preserve line breaks <= grapheme breaks
1251                 // and prevent line breaks inside graphemes
1252                 candidateGraphemeBreak = current;
1253                 candidateGraphemeBreakWidth = currentWidth;
1254                 if (glyph->fMayLineBreakBefore) {
1255                     candidateLineBreak = current;
1256                     candidateLineBreakWidth = currentWidth;
1257                 }
1258             }
1259         }
1260 
1261         SkScalar glyphWidth = glyph->fAdvance.fX;
1262         // Break when overwidth, the glyph has a visual representation, and some space is used.
1263         if (width < currentWidth + glyphWidth && glyph->fHasVisual && candidateGraphemeBreakWidth > 0){
1264             if (candidateLineBreak != beginning) {
1265                 beginning = candidateLineBreak;
1266                 currentWidth -= candidateLineBreakWidth;
1267                 candidateGraphemeBreakWidth -= candidateLineBreakWidth;
1268                 candidateLineBreakWidth = 0;
1269             } else if (candidateGraphemeBreak != beginning) {
1270                 beginning = candidateGraphemeBreak;
1271                 candidateLineBreak = beginning;
1272                 currentWidth -= candidateGraphemeBreakWidth;
1273                 candidateGraphemeBreakWidth = 0;
1274                 candidateLineBreakWidth = 0;
1275             } else {
1276                 SK_ABORT("");
1277             }
1278 
1279             if (width < currentWidth) {
1280                 if (width < candidateGraphemeBreakWidth) {
1281                     candidateGraphemeBreak = candidateLineBreak;
1282                     candidateGraphemeBreakWidth = candidateLineBreakWidth;
1283                 }
1284                 current = candidateGraphemeBreak;
1285                 currentWidth = candidateGraphemeBreakWidth;
1286             }
1287 
1288             glyph = beginning.current();
1289             if (glyph) {
1290                 glyph->fMustLineBreakBefore = true;
1291             }
1292 
1293         } else {
1294             current.next();
1295             currentWidth += glyphWidth;
1296         }
1297     }
1298 }
1299 
1300 // Reorder the runs and glyphs per line and write them out.
1301 {
1302     ShapedRunGlyphIterator previousBreak(runs);
1303     ShapedRunGlyphIterator glyphIterator(runs);
1304     int previousRunIndex = -1;
1305     while (glyphIterator.current()) {
1306         const ShapedRunGlyphIterator current = glyphIterator;
1307         ShapedGlyph* nextGlyph = glyphIterator.next();
1308 
1309         if (previousRunIndex != current.fRunIndex) {
1310 #ifdef ENABLE_TEXT_ENHANCE
1311             RSFontMetrics metrics;
1312             runs[current.fRunIndex].fFont.GetMetrics(&metrics);
1313 #else
1314             SkFontMetrics metrics;
1315             runs[current.fRunIndex].fFont.getMetrics(&metrics);
1316 #endif
1317             previousRunIndex = current.fRunIndex;
1318         }
1319 
1320         // Nothing can be written until the baseline is known.
1321         if (!(nextGlyph == nullptr || nextGlyph->fMustLineBreakBefore)) {
1322             continue;
1323         }
1324 
1325         int numRuns = current.fRunIndex - previousBreak.fRunIndex + 1;
1326         AutoSTMalloc<4, SkBidiIterator::Level> runLevels(numRuns);
1327         for (int i = 0; i < numRuns; ++i) {
1328             runLevels[i] = runs[previousBreak.fRunIndex + i].fLevel;
1329         }
1330         AutoSTMalloc<4, int32_t> logicalFromVisual(numRuns);
1331         fUnicode->reorderVisual(runLevels, numRuns, logicalFromVisual);
1332 
1333         // step through the runs in reverse visual order and the glyphs in reverse logical order
1334         // until a visible glyph is found and force them to the end of the visual line.
1335 
1336         handler->beginLine();
1337 
1338         struct SubRun { const ShapedRun& run; size_t startGlyphIndex; size_t endGlyphIndex; };
1339         auto makeSubRun = [&runs, &previousBreak, &current, &logicalFromVisual](size_t visualIndex){
1340             int logicalIndex = previousBreak.fRunIndex + logicalFromVisual[visualIndex];
1341             const auto& run = runs[logicalIndex];
1342             size_t startGlyphIndex = (logicalIndex == previousBreak.fRunIndex)
1343                                    ? previousBreak.fGlyphIndex
1344                                    : 0;
1345             size_t endGlyphIndex = (logicalIndex == current.fRunIndex)
1346                                  ? current.fGlyphIndex + 1
1347                                  : run.fNumGlyphs;
1348             return SubRun{ run, startGlyphIndex, endGlyphIndex };
1349         };
1350         auto makeRunInfo = [](const SubRun& sub) {
1351             uint32_t startUtf8 = sub.run.fGlyphs[sub.startGlyphIndex].fCluster;
1352             uint32_t endUtf8 = (sub.endGlyphIndex < sub.run.fNumGlyphs)
1353                              ? sub.run.fGlyphs[sub.endGlyphIndex].fCluster
1354                              : sub.run.fUtf8Range.end();
1355 
1356             SkVector advance = SkVector::Make(0, 0);
1357             for (size_t i = sub.startGlyphIndex; i < sub.endGlyphIndex; ++i) {
1358                 advance += sub.run.fGlyphs[i].fAdvance;
1359             }
1360 
1361             return RunHandler::RunInfo{
1362                 sub.run.fFont,
1363                 sub.run.fLevel,
1364                 advance,
1365                 sub.endGlyphIndex - sub.startGlyphIndex,
1366                 RunHandler::Range(startUtf8, endUtf8 - startUtf8)
1367             };
1368         };
1369 
1370         for (int i = 0; i < numRuns; ++i) {
1371             handler->runInfo(makeRunInfo(makeSubRun(i)));
1372         }
1373         handler->commitRunInfo();
1374         for (int i = 0; i < numRuns; ++i) {
1375             SubRun sub = makeSubRun(i);
1376             append(handler, makeRunInfo(sub), sub.run, sub.startGlyphIndex, sub.endGlyphIndex);
1377         }
1378 
1379         handler->commitLine();
1380 
1381         previousRunIndex = -1;
1382         previousBreak = glyphIterator;
1383     }
1384 }
1385 }
1386 
1387 void ShapeDontWrapOrReorder::wrap(char const * const utf8, size_t utf8Bytes,
1388                                   const BiDiRunIterator& bidi,
1389                                   const LanguageRunIterator& language,
1390                                   const ScriptRunIterator& script,
1391                                   const FontRunIterator& font,
1392                                   RunIteratorQueue& runSegmenter,
1393                                   const Feature* features, size_t featuresSize,
1394                                   SkScalar width,
1395                                   RunHandler* handler) const
1396 {
1397     sk_ignore_unused_variable(width);
1398     TArray<ShapedRun> runs;
1399 
1400     const char* utf8Start = nullptr;
1401     const char* utf8End = utf8;
1402     while (runSegmenter.advanceRuns()) {
1403         utf8Start = utf8End;
1404         utf8End = utf8 + runSegmenter.endOfCurrentRun();
1405 
1406         runs.emplace_back(shape(utf8, utf8Bytes,
1407                                 utf8Start, utf8End,
1408                                 bidi, language, script, font,
1409                                 features, featuresSize));
1410     }
1411 
1412     handler->beginLine();
1413     for (const auto& run : runs) {
1414         const RunHandler::RunInfo info = {
1415             run.fFont,
1416             run.fLevel,
1417             run.fAdvance,
1418             run.fNumGlyphs,
1419             run.fUtf8Range
1420         };
1421         handler->runInfo(info);
1422     }
1423     handler->commitRunInfo();
1424     for (const auto& run : runs) {
1425         const RunHandler::RunInfo info = {
1426             run.fFont,
1427             run.fLevel,
1428             run.fAdvance,
1429             run.fNumGlyphs,
1430             run.fUtf8Range
1431         };
1432         append(handler, info, run, 0, run.fNumGlyphs);
1433     }
1434     handler->commitLine();
1435 }
1436 
1437 class HBLockedFaceCache {
1438 public:
1439     HBLockedFaceCache(SkLRUCache<SkTypefaceID, HBFont>& lruCache, SkMutex& mutex)
1440         : fLRUCache(lruCache), fMutex(mutex)
1441     {
1442         fMutex.acquire();
1443     }
1444     HBLockedFaceCache(const HBLockedFaceCache&) = delete;
1445     HBLockedFaceCache& operator=(const HBLockedFaceCache&) = delete;
1446     HBLockedFaceCache& operator=(HBLockedFaceCache&&) = delete;
1447 
1448     ~HBLockedFaceCache() {
1449         fMutex.release();
1450     }
1451 
1452     HBFont* find(SkTypefaceID fontId) {
1453         return fLRUCache.find(fontId);
1454     }
1455     HBFont* insert(SkTypefaceID fontId, HBFont hbFont) {
1456         return fLRUCache.insert(fontId, std::move(hbFont));
1457     }
1458     void reset() {
1459         fLRUCache.reset();
1460     }
1461 private:
1462     SkLRUCache<SkTypefaceID, HBFont>& fLRUCache;
1463     SkMutex& fMutex;
1464 };
1465 static HBLockedFaceCache get_hbFace_cache() {
1466     static SkMutex gHBFaceCacheMutex;
1467     static SkLRUCache<SkTypefaceID, HBFont> gHBFaceCache(100);
1468     return HBLockedFaceCache(gHBFaceCache, gHBFaceCacheMutex);
1469 }
1470 
1471 ShapedRun ShaperHarfBuzz::shape(char const * const utf8,
1472                                   size_t const utf8Bytes,
1473                                   char const * const utf8Start,
1474                                   char const * const utf8End,
1475                                   const BiDiRunIterator& bidi,
1476                                   const LanguageRunIterator& language,
1477                                   const ScriptRunIterator& script,
1478                                   const FontRunIterator& font,
1479                                   Feature const * const features, size_t const featuresSize) const
1480 {
1481     size_t utf8runLength = utf8End - utf8Start;
1482     ShapedRun run(RunHandler::Range(utf8Start - utf8, utf8runLength),
1483                   font.currentFont(), bidi.currentLevel(), nullptr, 0);
1484 
1485     hb_buffer_t* buffer = fBuffer.get();
1486     SkAutoTCallVProc<hb_buffer_t, hb_buffer_clear_contents> autoClearBuffer(buffer);
1487     hb_buffer_set_content_type(buffer, HB_BUFFER_CONTENT_TYPE_UNICODE);
1488     hb_buffer_set_cluster_level(buffer, HB_BUFFER_CLUSTER_LEVEL_MONOTONE_CHARACTERS);
1489 
1490     // Documentation for HB_BUFFER_FLAG_BOT/EOT at 763e5466c0a03a7c27020e1e2598e488612529a7.
1491     // Currently BOT forces a dotted circle when first codepoint is a mark; EOT has no effect.
1492     // Avoid adding dotted circle, re-evaluate if BOT/EOT change. See https://skbug.com/9618.
1493     // hb_buffer_set_flags(buffer, HB_BUFFER_FLAG_BOT | HB_BUFFER_FLAG_EOT);
1494 
1495     // Add precontext.
1496     hb_buffer_add_utf8(buffer, utf8, utf8Start - utf8, utf8Start - utf8, 0);
1497 
1498     // Populate the hb_buffer directly with utf8 cluster indexes.
1499     const char* utf8Current = utf8Start;
1500     while (utf8Current < utf8End) {
1501         unsigned int cluster = utf8Current - utf8;
1502         hb_codepoint_t u = utf8_next(&utf8Current, utf8End);
1503         hb_buffer_add(buffer, u, cluster);
1504     }
1505 
1506     // Add postcontext.
1507     hb_buffer_add_utf8(buffer, utf8Current, utf8 + utf8Bytes - utf8Current, 0, 0);
1508 
1509     hb_direction_t direction = is_LTR(bidi.currentLevel()) ? HB_DIRECTION_LTR:HB_DIRECTION_RTL;
1510     hb_buffer_set_direction(buffer, direction);
1511     hb_buffer_set_script(buffer, hb_script_from_iso15924_tag((hb_tag_t)script.currentScript()));
1512     // Buffers with HB_LANGUAGE_INVALID race since hb_language_get_default is not thread safe.
1513     // The user must provide a language, but may provide data hb_language_from_string cannot use.
1514     // Use "und" for the undefined language in this case (RFC5646 4.1 5).
1515     hb_language_t hbLanguage = hb_language_from_string(language.currentLanguage(), -1);
1516     if (hbLanguage == HB_LANGUAGE_INVALID) {
1517         hbLanguage = fUndefinedLanguage;
1518     }
1519     hb_buffer_set_language(buffer, hbLanguage);
1520     hb_buffer_guess_segment_properties(buffer);
1521 
1522     // TODO: better cache HBFace (data) / hbfont (typeface)
1523     // An HBFace is expensive (it sanitizes the bits).
1524     // An HBFont is fairly inexpensive.
1525     // An HBFace is actually tied to the data, not the typeface.
1526     // The size of 100 here is completely arbitrary and used to match libtxt.
1527     HBFont hbFont;
1528     {
1529         HBLockedFaceCache cache = get_hbFace_cache();
1530 #ifdef ENABLE_TEXT_ENHANCE
1531         uint32_t dataId = const_cast<RSFont&>(font.currentFont()).GetTypeface()->GetUniqueID();
1532 #else
1533         SkTypefaceID dataId = font.currentFont().getTypeface()->uniqueID();
1534 #endif
1535         HBFont* typefaceFontCached = cache.find(dataId);
1536         if (!typefaceFontCached) {
1537 #ifdef ENABLE_TEXT_ENHANCE
1538             HBFont typefaceFont(create_typeface_hb_font(*const_cast<RSFont&>(font.currentFont()).GetTypeface()));
1539 #else
1540             HBFont typefaceFont(create_typeface_hb_font(*font.currentFont().getTypeface()));
1541 #endif
1542             typefaceFontCached = cache.insert(dataId, std::move(typefaceFont));
1543         }
1544         hbFont = create_sub_hb_font(font.currentFont(), *typefaceFontCached);
1545     }
1546     if (!hbFont) {
1547         return run;
1548     }
1549 
1550     STArray<32, hb_feature_t> hbFeatures;
1551     for (const auto& feature : SkSpan(features, featuresSize)) {
1552         if (feature.end < SkTo<size_t>(utf8Start - utf8) ||
1553                           SkTo<size_t>(utf8End   - utf8)  <= feature.start)
1554         {
1555             continue;
1556         }
1557         if (feature.start <= SkTo<size_t>(utf8Start - utf8) &&
1558                              SkTo<size_t>(utf8End   - utf8) <= feature.end)
1559         {
1560             hbFeatures.push_back({ (hb_tag_t)feature.tag, feature.value,
1561                                    HB_FEATURE_GLOBAL_START, HB_FEATURE_GLOBAL_END});
1562         } else {
1563             hbFeatures.push_back({ (hb_tag_t)feature.tag, feature.value,
1564                                    SkTo<unsigned>(feature.start), SkTo<unsigned>(feature.end)});
1565         }
1566     }
1567 
1568     hb_shape(hbFont.get(), buffer, hbFeatures.data(), hbFeatures.size());
1569     unsigned len = hb_buffer_get_length(buffer);
1570     if (len == 0) {
1571         return run;
1572     }
1573 
1574     if (direction == HB_DIRECTION_RTL) {
1575         // Put the clusters back in logical order.
1576         // Note that the advances remain ltr.
1577         hb_buffer_reverse(buffer);
1578     }
1579     hb_glyph_info_t* info = hb_buffer_get_glyph_infos(buffer, nullptr);
1580     hb_glyph_position_t* pos = hb_buffer_get_glyph_positions(buffer, nullptr);
1581 
1582     run = ShapedRun(RunHandler::Range(utf8Start - utf8, utf8runLength),
1583                     font.currentFont(), bidi.currentLevel(),
1584                     std::unique_ptr<ShapedGlyph[]>(new ShapedGlyph[len]), len);
1585 
1586     // Undo skhb_position with (1.0/(1<<16)) and scale as needed.
1587     AutoSTArray<32, SkGlyphID> glyphIDs(len);
1588     for (unsigned i = 0; i < len; i++) {
1589         glyphIDs[i] = info[i].codepoint;
1590     }
1591 #ifdef ENABLE_TEXT_ENHANCE
1592     AutoSTArray<32, RSRect> glyphBounds(len);
1593     run.fFont.GetWidths(glyphIDs.get(), len, nullptr, glyphBounds.get());
1594 #else
1595     AutoSTArray<32, SkRect> glyphBounds(len);
1596     SkPaint p;
1597     run.fFont.getBounds(glyphIDs.get(), len, glyphBounds.get(), &p);
1598 #endif
1599 
1600 #ifdef ENABLE_TEXT_ENHANCE
1601     double SkScalarFromHBPosX = +(1.52587890625e-5) * run.fFont.GetScaleX();
1602 #else
1603     double SkScalarFromHBPosX = +(1.52587890625e-5) * run.fFont.getScaleX();
1604 #endif
1605     double SkScalarFromHBPosY = -(1.52587890625e-5);  // HarfBuzz y-up, Skia y-down
1606     SkVector runAdvance = { 0, 0 };
1607     for (unsigned i = 0; i < len; i++) {
1608         ShapedGlyph& glyph = run.fGlyphs[i];
1609         glyph.fID = info[i].codepoint;
1610         glyph.fCluster = info[i].cluster;
1611         glyph.fOffset.fX = pos[i].x_offset * SkScalarFromHBPosX;
1612         glyph.fOffset.fY = pos[i].y_offset * SkScalarFromHBPosY;
1613         glyph.fAdvance.fX = pos[i].x_advance * SkScalarFromHBPosX;
1614         glyph.fAdvance.fY = pos[i].y_advance * SkScalarFromHBPosY;
1615 
1616 #ifdef ENABLE_TEXT_ENHANCE
1617         glyph.fHasVisual = !glyphBounds[i].IsEmpty(); //!font->currentTypeface()->glyphBoundsAreZero(glyph.fID);
1618 #else
1619         glyph.fHasVisual = !glyphBounds[i].isEmpty(); //!font->currentTypeface()->glyphBoundsAreZero(glyph.fID);
1620 #endif
1621 #if SK_HB_VERSION_CHECK(1, 5, 0)
1622         glyph.fUnsafeToBreak = info[i].mask & HB_GLYPH_FLAG_UNSAFE_TO_BREAK;
1623 #else
1624         glyph.fUnsafeToBreak = false;
1625 #endif
1626         glyph.fMustLineBreakBefore = false;
1627 
1628         runAdvance += glyph.fAdvance;
1629     }
1630     run.fAdvance = runAdvance;
1631 
1632     return run;
1633 }
1634 }  // namespace
1635 
1636 #if !defined(SK_DISABLE_LEGACY_SKSHAPER_FUNCTIONS)
1637 
1638 #if defined(SK_UNICODE_ICU_IMPLEMENTATION)
1639 #include "modules/skunicode/include/SkUnicode_icu.h"
1640 #endif
1641 
1642 #if defined(SK_UNICODE_LIBGRAPHEME_IMPLEMENTATION)
1643 #include "modules/skunicode/include/SkUnicode_libgrapheme.h"
1644 #endif
1645 
1646 #if defined(SK_UNICODE_ICU4X_IMPLEMENTATION)
1647 #include "modules/skunicode/include/SkUnicode_icu4x.h"
1648 #endif
1649 
1650 static sk_sp<SkUnicode> get_unicode() {
1651 #if defined(SK_UNICODE_ICU_IMPLEMENTATION)
1652     if (auto unicode = SkUnicodes::ICU::Make()) {
1653         return unicode;
1654     }
1655 #endif  // defined(SK_UNICODE_ICU_IMPLEMENTATION)
1656 #if defined(SK_UNICODE_LIBGRAPHEME_IMPLEMENTATION)
1657     if (auto unicode = SkUnicodes::Libgrapheme::Make()) {
1658         return unicode;
1659     }
1660 #endif
1661 #if defined(SK_UNICODE_ICU4X_IMPLEMENTATION)
1662     if (auto unicode = SkUnicodes::ICU4X::Make()) {
1663         return unicode;
1664     }
1665 #endif
1666     return nullptr;
1667 }
1668 
1669 #ifdef ENABLE_DRAWING_ADAPTER
1670 namespace SkiaRsText {
1671 #endif
1672 std::unique_ptr<SkShaper::ScriptRunIterator>
1673 SkShaper::MakeHbIcuScriptRunIterator(const char* utf8, size_t utf8Bytes) {
1674     return SkShapers::HB::ScriptRunIterator(utf8, utf8Bytes);
1675 }
1676 
1677 std::unique_ptr<SkShaper::ScriptRunIterator>
1678 SkShaper::MakeSkUnicodeHbScriptRunIterator(const char* utf8, size_t utf8Bytes) {
1679     return SkShapers::HB::ScriptRunIterator(utf8, utf8Bytes);
1680 }
1681 
1682 std::unique_ptr<SkShaper::ScriptRunIterator> SkShaper::MakeSkUnicodeHbScriptRunIterator(
1683         const char* utf8, size_t utf8Bytes, SkFourByteTag script) {
1684     return SkShapers::HB::ScriptRunIterator(utf8, utf8Bytes, script);
1685 }
1686 
1687 #ifdef ENABLE_TEXT_ENHANCE
1688 std::unique_ptr<SkShaper> SkShaper::MakeShaperDrivenWrapper(std::shared_ptr<RSFontMgr> fontmgr) {
1689     return SkShapers::HB::ShaperDrivenWrapper(get_unicode(), fontmgr);
1690 }
1691 
1692 std::unique_ptr<SkShaper> SkShaper::MakeShapeThenWrap(std::shared_ptr<RSFontMgr> fontmgr) {
1693     return SkShapers::HB::ShapeThenWrap(get_unicode(), fontmgr);
1694 }
1695 #else
1696 std::unique_ptr<SkShaper> SkShaper::MakeShaperDrivenWrapper(sk_sp<SkFontMgr> fontmgr) {
1697     return SkShapers::HB::ShaperDrivenWrapper(get_unicode(), fontmgr);
1698 }
1699 
1700 std::unique_ptr<SkShaper> SkShaper::MakeShapeThenWrap(sk_sp<SkFontMgr> fontmgr) {
1701     return SkShapers::HB::ShapeThenWrap(get_unicode(), fontmgr);
1702 }
1703 #endif // ENABLE_TEXT_ENHANCE
1704 
1705 void SkShaper::PurgeHarfBuzzCache() { SkShapers::HB::PurgeCaches(); }
1706 #endif  // !defined(SK_DISABLE_LEGACY_SKSHAPER_FUNCTIONS)
1707 
1708 namespace SkShapers::HB {
1709 #ifdef ENABLE_TEXT_ENHANCE
1710 std::unique_ptr<SkShaper> ShaperDrivenWrapper(sk_sp<SkUnicode> unicode,
1711                                               std::shared_ptr<RSFontMgr> fallback) {
1712 #else
1713 std::unique_ptr<SkShaper> ShaperDrivenWrapper(sk_sp<SkUnicode> unicode,
1714                                               sk_sp<SkFontMgr> fallback) {
1715 #endif
1716     if (!unicode) {
1717         return nullptr;
1718     }
1719     HBBuffer buffer(hb_buffer_create());
1720     if (!buffer) {
1721         SkDEBUGF("Could not create hb_buffer");
1722         return nullptr;
1723     }
1724     return std::make_unique<::ShaperDrivenWrapper>(
1725             unicode, std::move(buffer), std::move(fallback));
1726 }
1727 
1728 #ifdef ENABLE_TEXT_ENHANCE
1729 std::unique_ptr<SkShaper> ShapeThenWrap(sk_sp<SkUnicode> unicode,
1730                                         std::shared_ptr<RSFontMgr> fallback) {
1731 
1732 #else
1733 std::unique_ptr<SkShaper> ShapeThenWrap(sk_sp<SkUnicode> unicode,
1734                                         sk_sp<SkFontMgr> fallback) {
1735 #endif
1736     if (!unicode) {
1737         return nullptr;
1738     }
1739     HBBuffer buffer(hb_buffer_create());
1740     if (!buffer) {
1741         SkDEBUGF("Could not create hb_buffer");
1742         return nullptr;
1743     }
1744     return std::make_unique<::ShapeThenWrap>(
1745             unicode, std::move(buffer), std::move(fallback));
1746 }
1747 
1748 #ifdef ENABLE_TEXT_ENHANCE
1749 std::unique_ptr<SkShaper> ShapeDontWrapOrReorder(sk_sp<SkUnicode> unicode,
1750                                                  std::shared_ptr<RSFontMgr> fallback) {
1751 #else
1752 std::unique_ptr<SkShaper> ShapeDontWrapOrReorder(sk_sp<SkUnicode> unicode,
1753                                                  sk_sp<SkFontMgr> fallback) {
1754 #endif
1755     if (!unicode) {
1756         return nullptr;
1757     }
1758     HBBuffer buffer(hb_buffer_create());
1759     if (!buffer) {
1760         SkDEBUGF("Could not create hb_buffer");
1761         return nullptr;
1762     }
1763     return std::make_unique<::ShapeDontWrapOrReorder>(
1764             unicode, std::move(buffer), std::move(fallback));
1765 }
1766 
1767 std::unique_ptr<SkShaper::ScriptRunIterator> ScriptRunIterator(const char* utf8, size_t utf8Bytes) {
1768     return std::make_unique<SkUnicodeHbScriptRunIterator>(utf8, utf8Bytes, HB_SCRIPT_UNKNOWN);
1769 }
1770 std::unique_ptr<SkShaper::ScriptRunIterator> ScriptRunIterator(const char* utf8,
1771                                                                size_t utf8Bytes,
1772                                                                SkFourByteTag script) {
1773     return std::make_unique<SkUnicodeHbScriptRunIterator>(
1774             utf8, utf8Bytes, hb_script_from_iso15924_tag((hb_tag_t)script));
1775 }
1776 
1777 void PurgeCaches() {
1778     HBLockedFaceCache cache = get_hbFace_cache();
1779     cache.reset();
1780 }
1781 }  // namespace SkShapers::HB
1782 #ifdef ENABLE_DRAWING_ADAPTER
1783 } // namespace SkiaRsText
1784 #endif // ENABLE_DRAWING_ADAPTER