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1 /*
2  * Copyright (C) 2007, 2008 Apple Inc. All rights reserved.
3  *           (C) 2007, 2008 Nikolas Zimmermann <zimmermann@kde.org>
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  *
14  * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
15  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
17  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
18  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
19  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
20  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
21  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
22  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
24  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25  */
26 
27 #include "config.h"
28 #include "CSSFontSelector.h"
29 
30 #include "AtomicString.h"
31 #include "CachedFont.h"
32 #include "CSSFontFace.h"
33 #include "CSSFontFaceRule.h"
34 #include "CSSFontFaceSource.h"
35 #include "CSSFontFaceSrcValue.h"
36 #include "CSSMutableStyleDeclaration.h"
37 #include "CSSPrimitiveValue.h"
38 #include "CSSPropertyNames.h"
39 #include "CSSSegmentedFontFace.h"
40 #include "CSSUnicodeRangeValue.h"
41 #include "CSSValueKeywords.h"
42 #include "CSSValueList.h"
43 #include "DocLoader.h"
44 #include "Document.h"
45 #include "FontCache.h"
46 #include "FontFamilyValue.h"
47 #include "Frame.h"
48 #include "NodeList.h"
49 #include "RenderObject.h"
50 #include "Settings.h"
51 #include "SimpleFontData.h"
52 
53 #if ENABLE(SVG)
54 #include "SVGFontFaceElement.h"
55 #include "SVGNames.h"
56 #endif
57 
58 namespace WebCore {
59 
CSSFontSelector(Document * document)60 CSSFontSelector::CSSFontSelector(Document* document)
61     : m_document(document)
62 {
63     // FIXME: An old comment used to say there was no need to hold a reference to m_document
64     // because "we are guaranteed to be destroyed before the document". But there does not
65     // seem to be any such guarantee.
66 
67     ASSERT(m_document);
68     fontCache()->addClient(this);
69 }
70 
~CSSFontSelector()71 CSSFontSelector::~CSSFontSelector()
72 {
73     fontCache()->removeClient(this);
74     deleteAllValues(m_fontFaces);
75     deleteAllValues(m_locallyInstalledFontFaces);
76     deleteAllValues(m_fonts);
77 }
78 
isEmpty() const79 bool CSSFontSelector::isEmpty() const
80 {
81     return m_fonts.isEmpty();
82 }
83 
docLoader() const84 DocLoader* CSSFontSelector::docLoader() const
85 {
86     return m_document ? m_document->docLoader() : 0;
87 }
88 
addFontFaceRule(const CSSFontFaceRule * fontFaceRule)89 void CSSFontSelector::addFontFaceRule(const CSSFontFaceRule* fontFaceRule)
90 {
91     // Obtain the font-family property and the src property.  Both must be defined.
92     const CSSMutableStyleDeclaration* style = fontFaceRule->style();
93     RefPtr<CSSValue> fontFamily = style->getPropertyCSSValue(CSSPropertyFontFamily);
94     RefPtr<CSSValue> src = style->getPropertyCSSValue(CSSPropertySrc);
95     RefPtr<CSSValue> unicodeRange = style->getPropertyCSSValue(CSSPropertyUnicodeRange);
96     if (!fontFamily || !src || !fontFamily->isValueList() || !src->isValueList() || (unicodeRange && !unicodeRange->isValueList()))
97         return;
98 
99     CSSValueList* familyList = static_cast<CSSValueList*>(fontFamily.get());
100     if (!familyList->length())
101         return;
102 
103     CSSValueList* srcList = static_cast<CSSValueList*>(src.get());
104     if (!srcList->length())
105         return;
106 
107     CSSValueList* rangeList = static_cast<CSSValueList*>(unicodeRange.get());
108 
109     unsigned traitsMask = 0;
110 
111     if (RefPtr<CSSValue> fontStyle = style->getPropertyCSSValue(CSSPropertyFontStyle)) {
112         if (fontStyle->isPrimitiveValue()) {
113             RefPtr<CSSValueList> list = CSSValueList::createCommaSeparated();
114             list->append(fontStyle);
115             fontStyle = list;
116         } else if (!fontStyle->isValueList())
117             return;
118 
119         CSSValueList* styleList = static_cast<CSSValueList*>(fontStyle.get());
120         unsigned numStyles = styleList->length();
121         if (!numStyles)
122             return;
123 
124         for (unsigned i = 0; i < numStyles; ++i) {
125             switch (static_cast<CSSPrimitiveValue*>(styleList->itemWithoutBoundsCheck(i))->getIdent()) {
126                 case CSSValueAll:
127                     traitsMask |= FontStyleMask;
128                     break;
129                 case CSSValueNormal:
130                     traitsMask |= FontStyleNormalMask;
131                     break;
132                 case CSSValueItalic:
133                 case CSSValueOblique:
134                     traitsMask |= FontStyleItalicMask;
135                     break;
136                 default:
137                     break;
138             }
139         }
140     } else
141         traitsMask |= FontStyleMask;
142 
143     if (RefPtr<CSSValue> fontWeight = style->getPropertyCSSValue(CSSPropertyFontWeight)) {
144         if (fontWeight->isPrimitiveValue()) {
145             RefPtr<CSSValueList> list = CSSValueList::createCommaSeparated();
146             list->append(fontWeight);
147             fontWeight = list;
148         } else if (!fontWeight->isValueList())
149             return;
150 
151         CSSValueList* weightList = static_cast<CSSValueList*>(fontWeight.get());
152         unsigned numWeights = weightList->length();
153         if (!numWeights)
154             return;
155 
156         for (unsigned i = 0; i < numWeights; ++i) {
157             switch (static_cast<CSSPrimitiveValue*>(weightList->itemWithoutBoundsCheck(i))->getIdent()) {
158                 case CSSValueAll:
159                     traitsMask |= FontWeightMask;
160                     break;
161                 case CSSValueBolder:
162                 case CSSValueBold:
163                 case CSSValue700:
164                     traitsMask |= FontWeight700Mask;
165                     break;
166                 case CSSValueNormal:
167                 case CSSValue400:
168                     traitsMask |= FontWeight400Mask;
169                     break;
170                 case CSSValue900:
171                     traitsMask |= FontWeight900Mask;
172                     break;
173                 case CSSValue800:
174                     traitsMask |= FontWeight800Mask;
175                     break;
176                 case CSSValue600:
177                     traitsMask |= FontWeight600Mask;
178                     break;
179                 case CSSValue500:
180                     traitsMask |= FontWeight500Mask;
181                     break;
182                 case CSSValue300:
183                     traitsMask |= FontWeight300Mask;
184                     break;
185                 case CSSValueLighter:
186                 case CSSValue200:
187                     traitsMask |= FontWeight200Mask;
188                     break;
189                 case CSSValue100:
190                     traitsMask |= FontWeight100Mask;
191                     break;
192                 default:
193                     break;
194             }
195         }
196     } else
197         traitsMask |= FontWeightMask;
198 
199     if (RefPtr<CSSValue> fontVariant = style->getPropertyCSSValue(CSSPropertyFontVariant)) {
200         if (fontVariant->isPrimitiveValue()) {
201             RefPtr<CSSValueList> list = CSSValueList::createCommaSeparated();
202             list->append(fontVariant);
203             fontVariant = list;
204         } else if (!fontVariant->isValueList())
205             return;
206 
207         CSSValueList* variantList = static_cast<CSSValueList*>(fontVariant.get());
208         unsigned numVariants = variantList->length();
209         if (!numVariants)
210             return;
211 
212         for (unsigned i = 0; i < numVariants; ++i) {
213             switch (static_cast<CSSPrimitiveValue*>(variantList->itemWithoutBoundsCheck(i))->getIdent()) {
214                 case CSSValueAll:
215                     traitsMask |= FontVariantMask;
216                     break;
217                 case CSSValueNormal:
218                     traitsMask |= FontVariantNormalMask;
219                     break;
220                 case CSSValueSmallCaps:
221                     traitsMask |= FontVariantSmallCapsMask;
222                     break;
223                 default:
224                     break;
225             }
226         }
227     } else
228         traitsMask |= FontVariantNormalMask;
229 
230     // Each item in the src property's list is a single CSSFontFaceSource. Put them all into a CSSFontFace.
231     RefPtr<CSSFontFace> fontFace;
232 
233     int srcLength = srcList->length();
234 
235     bool foundLocal = false;
236     bool foundSVGFont = false;
237 
238     for (int i = 0; i < srcLength; i++) {
239         // An item in the list either specifies a string (local font name) or a URL (remote font to download).
240         CSSFontFaceSrcValue* item = static_cast<CSSFontFaceSrcValue*>(srcList->itemWithoutBoundsCheck(i));
241         CSSFontFaceSource* source = 0;
242 
243 #if ENABLE(SVG_FONTS)
244         foundSVGFont = item->isSVGFontFaceSrc() || item->svgFontFaceElement();
245 #endif
246         if (!item->isLocal()) {
247             Settings* settings = m_document ? m_document->frame() ? m_document->frame()->settings() : 0 : 0;
248             bool allowDownloading = foundSVGFont || (settings && settings->downloadableBinaryFontsEnabled());
249             if (allowDownloading && item->isSupportedFormat() && m_document) {
250                 CachedFont* cachedFont = m_document->docLoader()->requestFont(item->resource());
251                 if (cachedFont) {
252 #if ENABLE(SVG_FONTS)
253                     if (foundSVGFont)
254                         cachedFont->setSVGFont(true);
255 #endif
256                     source = new CSSFontFaceSource(item->resource(), cachedFont);
257                 }
258             }
259         } else {
260             source = new CSSFontFaceSource(item->resource());
261             foundLocal = true;
262         }
263 
264         if (!fontFace)
265             fontFace = CSSFontFace::create(static_cast<FontTraitsMask>(traitsMask));
266 
267         if (source) {
268 #if ENABLE(SVG_FONTS)
269             source->setSVGFontFaceElement(item->svgFontFaceElement());
270 #endif
271             fontFace->addSource(source);
272         }
273     }
274 
275     ASSERT(fontFace);
276 
277     if (fontFace && !fontFace->isValid())
278         return;
279 
280     if (rangeList) {
281         unsigned numRanges = rangeList->length();
282         for (unsigned i = 0; i < numRanges; i++) {
283             CSSUnicodeRangeValue* range = static_cast<CSSUnicodeRangeValue*>(rangeList->itemWithoutBoundsCheck(i));
284             fontFace->addRange(range->from(), range->to());
285         }
286     }
287 
288     // Hash under every single family name.
289     int familyLength = familyList->length();
290     for (int i = 0; i < familyLength; i++) {
291         CSSPrimitiveValue* item = static_cast<CSSPrimitiveValue*>(familyList->itemWithoutBoundsCheck(i));
292         String familyName;
293         if (item->primitiveType() == CSSPrimitiveValue::CSS_STRING)
294             familyName = static_cast<FontFamilyValue*>(item)->familyName();
295         else if (item->primitiveType() == CSSPrimitiveValue::CSS_IDENT) {
296             // We need to use the raw text for all the generic family types, since @font-face is a way of actually
297             // defining what font to use for those types.
298             String familyName;
299             switch (item->getIdent()) {
300                 case CSSValueSerif:
301                     familyName = "-webkit-serif";
302                     break;
303                 case CSSValueSansSerif:
304                     familyName = "-webkit-sans-serif";
305                     break;
306                 case CSSValueCursive:
307                     familyName = "-webkit-cursive";
308                     break;
309                 case CSSValueFantasy:
310                     familyName = "-webkit-fantasy";
311                     break;
312                 case CSSValueMonospace:
313                     familyName = "-webkit-monospace";
314                     break;
315                 default:
316                     break;
317             }
318         }
319 
320         if (familyName.isEmpty())
321             continue;
322 
323 #if ENABLE(SVG_FONTS)
324         // SVG allows several <font> elements with the same font-family, differing only
325         // in ie. font-variant. Be sure to pick up the right one - in getFontData below.
326         if (foundSVGFont && (traitsMask & FontVariantSmallCapsMask))
327             familyName += "-webkit-svg-small-caps";
328 #endif
329 
330         Vector<RefPtr<CSSFontFace> >* familyFontFaces = m_fontFaces.get(familyName);
331         if (!familyFontFaces) {
332             familyFontFaces = new Vector<RefPtr<CSSFontFace> >;
333             m_fontFaces.set(familyName, familyFontFaces);
334 
335             ASSERT(!m_locallyInstalledFontFaces.contains(familyName));
336             Vector<RefPtr<CSSFontFace> >* familyLocallyInstalledFaces;
337 
338             Vector<unsigned> locallyInstalledFontsTraitsMasks;
339             fontCache()->getTraitsInFamily(familyName, locallyInstalledFontsTraitsMasks);
340             unsigned numLocallyInstalledFaces = locallyInstalledFontsTraitsMasks.size();
341             if (numLocallyInstalledFaces) {
342                 familyLocallyInstalledFaces = new Vector<RefPtr<CSSFontFace> >;
343                 m_locallyInstalledFontFaces.set(familyName, familyLocallyInstalledFaces);
344 
345                 for (unsigned i = 0; i < numLocallyInstalledFaces; ++i) {
346                     RefPtr<CSSFontFace> locallyInstalledFontFace = CSSFontFace::create(static_cast<FontTraitsMask>(locallyInstalledFontsTraitsMasks[i]));
347                     locallyInstalledFontFace->addSource(new CSSFontFaceSource(familyName));
348                     ASSERT(locallyInstalledFontFace->isValid());
349                     familyLocallyInstalledFaces->append(locallyInstalledFontFace);
350                 }
351             }
352         }
353 
354         familyFontFaces->append(fontFace);
355     }
356 }
357 
fontLoaded()358 void CSSFontSelector::fontLoaded()
359 {
360     if (!m_document || m_document->inPageCache() || !m_document->renderer())
361         return;
362     m_document->recalcStyle(Document::Force);
363     m_document->renderer()->setNeedsLayoutAndPrefWidthsRecalc();
364 }
365 
fontCacheInvalidated()366 void CSSFontSelector::fontCacheInvalidated()
367 {
368     if (!m_document || m_document->inPageCache() || !m_document->renderer())
369         return;
370     m_document->recalcStyle(Document::Force);
371     m_document->renderer()->setNeedsLayoutAndPrefWidthsRecalc();
372 }
373 
fontDataForGenericFamily(Document * document,const FontDescription & fontDescription,const AtomicString & familyName)374 static FontData* fontDataForGenericFamily(Document* document, const FontDescription& fontDescription, const AtomicString& familyName)
375 {
376     if (!document || !document->frame())
377         return 0;
378 
379     const Settings* settings = document->frame()->settings();
380     if (!settings)
381         return 0;
382 
383     AtomicString genericFamily;
384     if (familyName == "-webkit-serif")
385         genericFamily = settings->serifFontFamily();
386     else if (familyName == "-webkit-sans-serif")
387         genericFamily = settings->sansSerifFontFamily();
388     else if (familyName == "-webkit-cursive")
389         genericFamily = settings->cursiveFontFamily();
390     else if (familyName == "-webkit-fantasy")
391         genericFamily = settings->fantasyFontFamily();
392     else if (familyName == "-webkit-monospace")
393         genericFamily = settings->fixedFontFamily();
394     else if (familyName == "-webkit-standard")
395         genericFamily = settings->standardFontFamily();
396 
397     if (!genericFamily.isEmpty())
398         return fontCache()->getCachedFontData(fontCache()->getCachedFontPlatformData(fontDescription, genericFamily));
399 
400     return 0;
401 }
402 
403 static FontTraitsMask desiredTraitsMaskForComparison;
404 
compareFontFaces(CSSFontFace * first,CSSFontFace * second)405 static inline bool compareFontFaces(CSSFontFace* first, CSSFontFace* second)
406 {
407     FontTraitsMask firstTraitsMask = first->traitsMask();
408     FontTraitsMask secondTraitsMask = second->traitsMask();
409 
410     bool firstHasDesiredVariant = firstTraitsMask & desiredTraitsMaskForComparison & FontVariantMask;
411     bool secondHasDesiredVariant = secondTraitsMask & desiredTraitsMaskForComparison & FontVariantMask;
412 
413     if (firstHasDesiredVariant != secondHasDesiredVariant)
414         return firstHasDesiredVariant;
415 
416     bool firstHasDesiredStyle = firstTraitsMask & desiredTraitsMaskForComparison & FontStyleMask;
417     bool secondHasDesiredStyle = secondTraitsMask & desiredTraitsMaskForComparison & FontStyleMask;
418 
419     if (firstHasDesiredStyle != secondHasDesiredStyle)
420         return firstHasDesiredStyle;
421 
422     if (secondTraitsMask & desiredTraitsMaskForComparison & FontWeightMask)
423         return false;
424     if (firstTraitsMask & desiredTraitsMaskForComparison & FontWeightMask)
425         return true;
426 
427     // http://www.w3.org/TR/2002/WD-css3-webfonts-20020802/#q46 says: "If there are fewer then 9 weights in the family, the default algorithm
428     // for filling the "holes" is as follows. If '500' is unassigned, it will be assigned the same font as '400'. If any of the values '600',
429     // '700', '800', or '900' remains unassigned, they are assigned to the same face as the next darker assigned keyword, if any, or the next
430     // lighter one otherwise. If any of '300', '200', or '100' remains unassigned, it is assigned to the next lighter assigned keyword, if any,
431     // or the next darker otherwise."
432     // For '400', we made up our own rule (which then '500' follows).
433 
434     static const unsigned fallbackRuleSets = 9;
435     static const unsigned rulesPerSet = 8;
436     static const FontTraitsMask weightFallbackRuleSets[fallbackRuleSets][rulesPerSet] = {
437         { FontWeight200Mask, FontWeight300Mask, FontWeight400Mask, FontWeight500Mask, FontWeight600Mask, FontWeight700Mask, FontWeight800Mask, FontWeight900Mask },
438         { FontWeight100Mask, FontWeight300Mask, FontWeight400Mask, FontWeight500Mask, FontWeight600Mask, FontWeight700Mask, FontWeight800Mask, FontWeight900Mask },
439         { FontWeight200Mask, FontWeight100Mask, FontWeight400Mask, FontWeight500Mask, FontWeight600Mask, FontWeight700Mask, FontWeight800Mask, FontWeight900Mask },
440         { FontWeight500Mask, FontWeight300Mask, FontWeight600Mask, FontWeight200Mask, FontWeight700Mask, FontWeight100Mask, FontWeight800Mask, FontWeight900Mask },
441         { FontWeight400Mask, FontWeight300Mask, FontWeight600Mask, FontWeight200Mask, FontWeight700Mask, FontWeight100Mask, FontWeight800Mask, FontWeight900Mask },
442         { FontWeight700Mask, FontWeight800Mask, FontWeight900Mask, FontWeight500Mask, FontWeight400Mask, FontWeight300Mask, FontWeight200Mask, FontWeight100Mask },
443         { FontWeight800Mask, FontWeight900Mask, FontWeight600Mask, FontWeight500Mask, FontWeight400Mask, FontWeight300Mask, FontWeight200Mask, FontWeight100Mask },
444         { FontWeight900Mask, FontWeight700Mask, FontWeight600Mask, FontWeight500Mask, FontWeight400Mask, FontWeight300Mask, FontWeight200Mask, FontWeight100Mask },
445         { FontWeight800Mask, FontWeight700Mask, FontWeight600Mask, FontWeight500Mask, FontWeight400Mask, FontWeight300Mask, FontWeight200Mask, FontWeight100Mask }
446     };
447 
448     unsigned ruleSetIndex = 0;
449     unsigned w = FontWeight100Bit;
450     while (!(desiredTraitsMaskForComparison & (1 << w))) {
451         w++;
452         ruleSetIndex++;
453     }
454 
455     ASSERT(ruleSetIndex < fallbackRuleSets);
456     const FontTraitsMask* weightFallbackRule = weightFallbackRuleSets[ruleSetIndex];
457     for (unsigned i = 0; i < rulesPerSet; ++i) {
458         if (secondTraitsMask & weightFallbackRule[i])
459             return false;
460         if (firstTraitsMask & weightFallbackRule[i])
461             return true;
462     }
463 
464     return false;
465 }
466 
getFontData(const FontDescription & fontDescription,const AtomicString & familyName)467 FontData* CSSFontSelector::getFontData(const FontDescription& fontDescription, const AtomicString& familyName)
468 {
469     if (m_fontFaces.isEmpty()) {
470         if (familyName.startsWith("-webkit-"))
471             return fontDataForGenericFamily(m_document, fontDescription, familyName);
472         return 0;
473     }
474 
475     String family = familyName.string();
476 
477 #if ENABLE(SVG_FONTS)
478     if (fontDescription.smallCaps())
479         family += "-webkit-svg-small-caps";
480 #endif
481 
482     Vector<RefPtr<CSSFontFace> >* familyFontFaces = m_fontFaces.get(family);
483     // If no face was found, then return 0 and let the OS come up with its best match for the name.
484     if (!familyFontFaces || familyFontFaces->isEmpty()) {
485         // If we were handed a generic family, but there was no match, go ahead and return the correct font based off our
486         // settings.
487         return fontDataForGenericFamily(m_document, fontDescription, familyName);
488     }
489 
490     HashMap<unsigned, RefPtr<CSSSegmentedFontFace> >* segmentedFontFaceCache = m_fonts.get(family);
491     if (!segmentedFontFaceCache) {
492         segmentedFontFaceCache = new HashMap<unsigned, RefPtr<CSSSegmentedFontFace> >;
493         m_fonts.set(family, segmentedFontFaceCache);
494     }
495 
496     FontTraitsMask traitsMask = fontDescription.traitsMask();
497 
498     RefPtr<CSSSegmentedFontFace> face = segmentedFontFaceCache->get(traitsMask);
499 
500     if (!face) {
501         face = CSSSegmentedFontFace::create(this);
502         segmentedFontFaceCache->set(traitsMask, face);
503         // Collect all matching faces and sort them in order of preference.
504         Vector<CSSFontFace*, 32> candidateFontFaces;
505         for (int i = familyFontFaces->size() - 1; i >= 0; --i) {
506             CSSFontFace* candidate = familyFontFaces->at(i).get();
507             unsigned candidateTraitsMask = candidate->traitsMask();
508             if ((traitsMask & FontStyleNormalMask) && !(candidateTraitsMask & FontStyleNormalMask))
509                 continue;
510             if ((traitsMask & FontVariantNormalMask) && !(candidateTraitsMask & FontVariantNormalMask))
511                 continue;
512             candidateFontFaces.append(candidate);
513         }
514 
515         if (Vector<RefPtr<CSSFontFace> >* familyLocallyInstalledFontFaces = m_locallyInstalledFontFaces.get(family)) {
516             unsigned numLocallyInstalledFontFaces = familyLocallyInstalledFontFaces->size();
517             for (unsigned i = 0; i < numLocallyInstalledFontFaces; ++i) {
518                 CSSFontFace* candidate = familyLocallyInstalledFontFaces->at(i).get();
519                 unsigned candidateTraitsMask = candidate->traitsMask();
520                 if ((traitsMask & FontStyleNormalMask) && !(candidateTraitsMask & FontStyleNormalMask))
521                     continue;
522                 if ((traitsMask & FontVariantNormalMask) && !(candidateTraitsMask & FontVariantNormalMask))
523                     continue;
524                 candidateFontFaces.append(candidate);
525             }
526         }
527 
528         desiredTraitsMaskForComparison = traitsMask;
529         std::stable_sort(candidateFontFaces.begin(), candidateFontFaces.end(), compareFontFaces);
530         unsigned numCandidates = candidateFontFaces.size();
531         for (unsigned i = 0; i < numCandidates; ++i)
532             face->appendFontFace(candidateFontFaces[i]);
533     }
534 
535     // We have a face.  Ask it for a font data.  If it cannot produce one, it will fail, and the OS will take over.
536     return face->getFontData(fontDescription);
537 }
538 
539 }
540