Add a working SkFontMgr_fontconfig.

src/ports/SkFontMgr_fontconfig.cpp

+/*
+ * Copyright 2014 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#include "SkDataTable.h"
+#include "SkFontDescriptor.h"
+#include "SkFontHost_FreeType_common.h"
+#include "SkFontMgr.h"
+#include "SkFontStyle.h"
+#include "SkMath.h"
+#include "SkString.h"
+#include "SkStream.h"
+#include "SkTDArray.h"
+#include "SkThread.h"
+#include "SkTypefaceCache.h"
+#include "SkOSFile.h"
+
+#include <fontconfig/fontconfig.h>
+
+// FC_POSTSCRIPT_NAME was added with b561ff20 which ended up in 2.10.92
+// Ubuntu 12.04 is on 2.8.0, 13.10 is on 2.10.93
+// Debian 7 is on 2.9.0, 8 is on 2.11
+// OpenSUSE 12.2 is on 2.9.0, 12.3 is on 2.10.2, 13.1 2.11.0
+// Fedora 19 is on 2.10.93
+#ifndef FC_POSTSCRIPT_NAME
+#    define FC_POSTSCRIPT_NAME  "postscriptname"
+#endif
+
+#ifdef SK_DEBUG
+#    include "SkTLS.h"
+#endif
+
+/** Since FontConfig is poorly documented, this gives a high level overview:
+ *
+ *  FcConfig is a handle to a FontConfig configuration instance. Each 'configuration' is independent
+ *  from any others which may exist. There exists a default global configuration which is created
+ *  and destroyed by FcInit and FcFini, but this default should not normally be used.
+ *  Instead, one should use FcConfigCreate and FcInit* to have a named local state.
+ *
+ *  FcPatterns are {objectName -> [element]} (maps from object names to a list of elements).
+ *  Each element is some internal data plus an FcValue which is a variant (a union with a type tag).
+ *  Lists of elements are not typed, except by convention. Any collection of FcValues must be
+ *  assumed to be heterogeneous by the code, but the code need not do anything particularly
+ *  interesting if the values go against convention.
+ *
+ *  Somewhat like DirectWrite, FontConfig supports synthetics through FC_EMBOLDEN and FC_MATRIX.
+ *  Like all synthetic information, such information must be passed with the font data.
+ */
+
+namespace {
+
+// Fontconfig is not threadsafe before 2.10.91. Before that, we lock with a global mutex.
+// See http://skbug.com/1497 for background.
+SK_DECLARE_STATIC_MUTEX(gFCMutex);
+
+#ifdef SK_DEBUG
+    void *CreateThreadFcLocked() { return SkNEW(bool); }
+    void DeleteThreadFcLocked(void* v) { SkDELETE(static_cast<bool*>(v)); }
+#   define THREAD_FC_LOCKED \
+        static_cast<bool*>(SkTLS::Get(CreateThreadFcLocked, DeleteThreadFcLocked))
+#endif
+
+struct FCLocker {
+    // Assume FcGetVersion() has always been thread safe.
+
+    FCLocker() {
+        if (FcGetVersion() < 21091) {
+            gFCMutex.acquire();
+        } else {
+            SkDEBUGCODE(bool* threadLocked = THREAD_FC_LOCKED);
+            SkASSERT(false == *threadLocked);
+            SkDEBUGCODE(*threadLocked = true);
+        }
+    }
+
+    ~FCLocker() {
+        AssertHeld();
+        if (FcGetVersion() < 21091) {
+            gFCMutex.release();
+        } else {
+            SkDEBUGCODE(*THREAD_FC_LOCKED = false);
+        }
+    }
+
+    static void AssertHeld() { SkDEBUGCODE(
+        if (FcGetVersion() < 21091) {
+            gFCMutex.assertHeld();
+        } else {
+            SkASSERT(true == *THREAD_FC_LOCKED);
+        }
+    ) }
+
+private:
+    bool fUnlock;

[mtklein, 2014/07/30 19:43:37]

Delete?

[bungeman-skia, 2014/08/08 21:45:24]

Done.

+};
+
+} // namespace
+
+template<typename T, void (*P)(T*)> void FcTDestroy(T* t) {
+    FCLocker::AssertHeld();
+    P(t);
+}
+template <typename T, void (*P)(T*)> class SkAutoFc
+    : public SkAutoTCallVProc<T, FcTDestroy<T, P> > {
+public:
+    SkAutoFc(T* obj) : SkAutoTCallVProc<T, FcTDestroy<T, P> >(obj) {}
+};
+
+typedef SkAutoFc<FcConfig, FcConfigDestroy> SkAutoFcConfig;
+typedef SkAutoFc<FcFontSet, FcFontSetDestroy> SkAutoFcFontSet;
+typedef SkAutoFc<FcLangSet, FcLangSetDestroy> SkAutoFcLangSet;
+typedef SkAutoFc<FcObjectSet, FcObjectSetDestroy> SkAutoFcObjectSet;
+typedef SkAutoFc<FcPattern, FcPatternDestroy> SkAutoFcPattern;
+
+static int get_int(FcPattern* pattern, const char object[], int missing) {
+    int value;
+    if (FcPatternGetInteger(pattern, object, 0, &value) != FcResultMatch) {
+        return missing;
+    }
+    return value;
+}
+
+static const char* get_string(FcPattern* pattern, const char object[], const char* missing = "") {
+    FcChar8* value;
+    if (FcPatternGetString(pattern, object, 0, &value) != FcResultMatch) {
+        return missing;
+    }
+    return (const char*)value;
+}
+
+enum SkWeakReturn {
+    kIsWeak_WeakReturn,
+    kIsStrong_WeakReturn,
+    kNoId_WeakReturn
+};
+/** Ideally there  would exist a call like
+ *  FcResult FcPatternIsWeak(pattern, object, id, FcBool* isWeak);
+ *
+ *  However, there is no such call and as of Fc 2.11.0 even FcPatternEquals ignores the weak bit.
+ *  Currently, the only reliable way of finding the weak bit is by its effect on matching.
+ *  The weak bit only affects the matching of FC_FAMILY and FC_POSTSCRIPT_NAME object values.
+ *  A element with the weak bit is scored after FC_LANG, without the weak bit is scored before.
+ *  Note that the weak bit is stored on the element, not on the value it holds.
+ */
+static SkWeakReturn is_weak(FcPattern* pattern, const char object[], int id) {
+    FCLocker::AssertHeld();
+
+    FcResult result;
+
+    // Create a copy of the pattern with only the value 'pattern'['object'['id']] in it.
+    // Internally, FontConfig pattern objects are linked lists, so faster to remove from head.
+    SkAutoFcObjectSet requestedObjectOnly(FcObjectSetBuild(object, NULL));
+    SkAutoFcPattern minimal(FcPatternFilter(pattern, requestedObjectOnly));
+    FcBool hasId = true;
+    for (int i = 0; hasId && i < id; ++i) {
+        hasId = FcPatternRemove(minimal, object, 0);
+    }
+    if (!hasId) {
+        return kNoId_WeakReturn;
+    }
+    FcValue value;
+    result = FcPatternGet(minimal, object, 0, &value);
+    if (result != FcResultMatch) {
+        return kNoId_WeakReturn;
+    }
+    while (hasId) {
+        hasId = FcPatternRemove(minimal, object, 1);
+    }
+
+    // Create a font set with two patterns.
+    // 1. the same 'object' as minimal and a lang object with only 'nomatchlang'.
+    // 2. a different 'object' from minimal and a lang object with only 'matchlang'.
+    SkAutoFcFontSet fontSet(FcFontSetCreate());
+
+    SkAutoFcLangSet strongLangSet(FcLangSetCreate());
+    FcLangSetAdd(strongLangSet, (const FcChar8*)"nomatchlang");
+    SkAutoFcPattern strong(FcPatternDuplicate(minimal));
+    FcPatternAddLangSet(strong, FC_LANG, strongLangSet);
+
+    SkAutoFcLangSet weakLangSet(FcLangSetCreate());
+    FcLangSetAdd(weakLangSet, (const FcChar8*)"matchlang");
+    SkAutoFcPattern weak(FcPatternCreate());
+    FcPatternAddString(weak, object, (const FcChar8*)"nomatchstring");
+    FcPatternAddLangSet(weak, FC_LANG, weakLangSet);
+
+    FcFontSetAdd(fontSet, strong.detach());
+    FcFontSetAdd(fontSet, weak.detach());
+
+    // Add 'matchlang' to the copy of the pattern.
+    FcPatternAddLangSet(minimal, FC_LANG, weakLangSet);
+
+    // Run a match against the copy of the pattern.
+    // If the 'id' was weak, then we should match the pattern with 'matchlang'.
+    // If the 'id' was strong, then we should match the pattern with 'nomatchlang'.
+
+    // Note that this config is only used for FcFontRenderPrepare, which we don't even want.
+    // However, there appears to be no way to match/sort without it.
+    SkAutoFcConfig config(FcConfigCreate());
+    FcFontSet* fontSets[1] = { fontSet };
+    SkAutoFcPattern match(FcFontSetMatch(config, fontSets, SK_ARRAY_COUNT(fontSets),
+                                         minimal, &result));
+
+    FcLangSet* matchLangSet;
+    FcPatternGetLangSet(match, FC_LANG, 0, &matchLangSet);
+    return FcLangEqual == FcLangSetHasLang(matchLangSet, (const FcChar8*)"matchlang")
+                        ? kIsWeak_WeakReturn : kIsStrong_WeakReturn;
+}
+
+/** Removes weak elements from either FC_FAMILY or FC_POSTSCRIPT_NAME objects in the property.
+ *  This can be quite expensive, and should not be used more than once per font lookup.
+ *  This removes all of the weak elements after the last strong element.
+ */
+static void remove_weak(FcPattern* pattern, const char object[]) {
+    FCLocker::AssertHeld();
+
+    SkAutoFcObjectSet requestedObjectOnly(FcObjectSetBuild(object, NULL));
+    SkAutoFcPattern minimal(FcPatternFilter(pattern, requestedObjectOnly));
+
+    int lastStrongId = -1;
+    int numIds;
+    SkWeakReturn result;
+    for (int id = 0; ; ++id) {
+        result = is_weak(minimal, object, 0);
+        if (kNoId_WeakReturn == result) {
+            numIds = id;
+            break;
+        }
+        if (kIsStrong_WeakReturn == result) {
+            lastStrongId = id;
+        }
+        SkAssertResult(FcPatternRemove(minimal, object, 0));
+    }
+
+    // If they were all weak, then leave the pattern alone.
+    if (lastStrongId < 0) {
+        return;
+    }
+
+    // Remove everything after the last strong.
+    for (int id = lastStrongId + 1; id < numIds; ++id) {
+        SkAssertResult(FcPatternRemove(pattern, object, lastStrongId + 1));
+    }
+}
+
+static int map_range(SkFixed value,
+                     SkFixed old_min, SkFixed old_max,
+                     SkFixed new_min, SkFixed new_max)
+{
+    SkASSERT(old_min < old_max);
+    SkASSERT(new_min <= new_max);
+    return new_min + SkMulDiv(value - old_min, new_max - new_min,
+                                     old_max - old_min);

[mtklein, 2014/07/30 19:43:37]

some funky formatting here?

[bungeman-skia, 2014/08/08 21:45:24]

It's... division!!! Maybe I could put a comment here like /* ---------- */.

+}
+
+static int ave(SkFixed a, SkFixed b) {
+    return SkFixedAve(a, b);
+}
+
+struct MapRanges {
+    SkFixed old_val;
+    SkFixed new_val;
+};
+
+static SkFixed map_ranges_fixed(SkFixed val, MapRanges const ranges[], int rangesCount) {
+    // -Inf to [0]
+    if (val < ranges[0].old_val) {
+        return ranges[0].new_val;
+    }
+
+    // Linear from [i] to ave([i], [i+1]), then from ave([i], [i+1]) to [i+1]
+    for (int i = 0; i < rangesCount - 1; ++i) {
+        if (val < ave(ranges[i].old_val, ranges[i+1].old_val)) {
+            return map_range(val, ranges[i].old_val, ave(ranges[i].old_val, ranges[i+1].old_val),
+                                  ranges[i].new_val, ave(ranges[i].new_val, ranges[i+1].new_val));
+        }
+        if (val < ranges[i+1].old_val) {
+            return map_range(val, ave(ranges[i].old_val, ranges[i+1].old_val), ranges[i+1].old_val,
+                                  ave(ranges[i].new_val, ranges[i+1].new_val), ranges[i+1].new_val);
+        }
+    }
+
+    // From [n] to +Inf
+    // if (fcweight < Inf)
+    return ranges[rangesCount-1].new_val;
+}
+
+static int map_ranges(int val, MapRanges const ranges[], int rangesCount) {
+    return SkFixedRoundToInt(map_ranges_fixed(SkIntToFixed(val), ranges, rangesCount));
+}
+
+template<int n> struct SkTFixed {
+    SK_COMPILE_ASSERT(-32768 <= n && n <= 32767, SkTFixed_n_not_in_range);
+    static const SkFixed value = static_cast<SkFixed>(n << 16);
+};
+
+static SkFontStyle skfontstyle_from_fcpattern(FcPattern* pattern) {
+    typedef SkFontStyle SkFS;
+
+    static const MapRanges weightRanges[] = {
+        { SkTFixed<FC_WEIGHT_THIN>::value,       SkTFixed<SkFS::kThin_Weight>::value },
+        { SkTFixed<FC_WEIGHT_EXTRALIGHT>::value, SkTFixed<SkFS::kExtraLight_Weight>::value },
+        { SkTFixed<FC_WEIGHT_LIGHT>::value,      SkTFixed<SkFS::kLight_Weight>::value },
+        { SkTFixed<FC_WEIGHT_REGULAR>::value,    SkTFixed<SkFS::kNormal_Weight>::value },
+        { SkTFixed<FC_WEIGHT_MEDIUM>::value,     SkTFixed<SkFS::kMedium_Weight>::value },
+        { SkTFixed<FC_WEIGHT_DEMIBOLD>::value,   SkTFixed<SkFS::kSemiBold_Weight>::value },
+        { SkTFixed<FC_WEIGHT_BOLD>::value,       SkTFixed<SkFS::kBold_Weight>::value },
+        { SkTFixed<FC_WEIGHT_EXTRABOLD>::value,  SkTFixed<SkFS::kExtraBold_Weight>::value },
+        { SkTFixed<FC_WEIGHT_BLACK>::value,      SkTFixed<SkFS::kBlack_Weight>::value },
+        { SkTFixed<FC_WEIGHT_EXTRABLACK>::value, SkTFixed<1000>::value },
+    };
+    int weight = map_ranges(get_int(pattern, FC_WEIGHT, FC_WEIGHT_REGULAR),
+                            weightRanges, SK_ARRAY_COUNT(weightRanges));
+
+    static const MapRanges widthRanges[] = {
+        { SkTFixed<FC_WIDTH_ULTRACONDENSED>::value, SkTFixed<SkFS::kUltraCondensed_Width>::value },
+        { SkTFixed<FC_WIDTH_EXTRACONDENSED>::value, SkTFixed<SkFS::kExtraCondensed_Width>::value },
+        { SkTFixed<FC_WIDTH_CONDENSED>::value,      SkTFixed<SkFS::kCondensed_Width>::value },
+        { SkTFixed<FC_WIDTH_SEMICONDENSED>::value,  SkTFixed<SkFS::kSemiCondensed_Width>::value },
+        { SkTFixed<FC_WIDTH_NORMAL>::value,         SkTFixed<SkFS::kNormal_Width>::value },
+        { SkTFixed<FC_WIDTH_SEMIEXPANDED>::value,   SkTFixed<SkFS::kSemiExpanded_Width>::value },
+        { SkTFixed<FC_WIDTH_EXPANDED>::value,       SkTFixed<SkFS::kExpanded_Width>::value },
+        { SkTFixed<FC_WIDTH_EXTRAEXPANDED>::value,  SkTFixed<SkFS::kExtraExpanded_Width>::value },
+        { SkTFixed<FC_WIDTH_ULTRAEXPANDED>::value,  SkTFixed<SkFS::kUltaExpanded_Width>::value },
+    };
+    int width = map_ranges(get_int(pattern, FC_WIDTH, FC_WIDTH_NORMAL),
+                           widthRanges, SK_ARRAY_COUNT(widthRanges));
+
+    SkFS::Slant slant = get_int(pattern, FC_SLANT, FC_SLANT_ROMAN) > 0
+                             ? SkFS::kItalic_Slant
+                             : SkFS::kUpright_Slant;
+
+    return SkFontStyle(weight, width, slant);
+}
+
+static void fcpattern_from_skfontstyle(SkFontStyle style, FcPattern* pattern) {
+    FCLocker::AssertHeld();
+
+    typedef SkFontStyle SkFS;
+
+    static const MapRanges weightRanges[] = {
+        { SkTFixed<SkFS::kThin_Weight>::value,       SkTFixed<FC_WEIGHT_THIN>::value },
+        { SkTFixed<SkFS::kExtraLight_Weight>::value, SkTFixed<FC_WEIGHT_EXTRALIGHT>::value },
+        { SkTFixed<SkFS::kLight_Weight>::value,      SkTFixed<FC_WEIGHT_LIGHT>::value },
+        { SkTFixed<SkFS::kNormal_Weight>::value,     SkTFixed<FC_WEIGHT_REGULAR>::value },
+        { SkTFixed<SkFS::kMedium_Weight>::value,     SkTFixed<FC_WEIGHT_MEDIUM>::value },
+        { SkTFixed<SkFS::kSemiBold_Weight>::value,   SkTFixed<FC_WEIGHT_DEMIBOLD>::value },
+        { SkTFixed<SkFS::kBold_Weight>::value,       SkTFixed<FC_WEIGHT_BOLD>::value },
+        { SkTFixed<SkFS::kExtraBold_Weight>::value,  SkTFixed<FC_WEIGHT_EXTRABOLD>::value },
+        { SkTFixed<SkFS::kBlack_Weight>::value,      SkTFixed<FC_WEIGHT_BLACK>::value },
+        { SkTFixed<1000>::value,                     SkTFixed<FC_WEIGHT_EXTRABLACK>::value },
+    };
+    int weight = map_ranges(style.weight(), weightRanges, SK_ARRAY_COUNT(weightRanges));
+
+    static const MapRanges widthRanges[] = {
+        { SkTFixed<SkFS::kUltraCondensed_Width>::value, SkTFixed<FC_WIDTH_ULTRACONDENSED>::value },
+        { SkTFixed<SkFS::kExtraCondensed_Width>::value, SkTFixed<FC_WIDTH_EXTRACONDENSED>::value },
+        { SkTFixed<SkFS::kCondensed_Width>::value,      SkTFixed<FC_WIDTH_CONDENSED>::value },
+        { SkTFixed<SkFS::kSemiCondensed_Width>::value,  SkTFixed<FC_WIDTH_SEMICONDENSED>::value },
+        { SkTFixed<SkFS::kNormal_Width>::value,         SkTFixed<FC_WIDTH_NORMAL>::value },
+        { SkTFixed<SkFS::kSemiExpanded_Width>::value,   SkTFixed<FC_WIDTH_SEMIEXPANDED>::value },
+        { SkTFixed<SkFS::kExpanded_Width>::value,       SkTFixed<FC_WIDTH_EXPANDED>::value },
+        { SkTFixed<SkFS::kExtraExpanded_Width>::value,  SkTFixed<FC_WIDTH_EXTRAEXPANDED>::value },
+        { SkTFixed<SkFS::kUltaExpanded_Width>::value,   SkTFixed<FC_WIDTH_ULTRAEXPANDED>::value },
+    };
+    int width = map_ranges(style.width(), widthRanges, SK_ARRAY_COUNT(widthRanges));
+
+    FcPatternAddInteger(pattern, FC_WEIGHT, weight);
+    FcPatternAddInteger(pattern, FC_WIDTH, width);
+    FcPatternAddInteger(pattern, FC_SLANT, style.isItalic() ? FC_SLANT_ITALIC : FC_SLANT_ROMAN);
+}
+
+static SkTypeface::Style sktypefacestyle_from_fcpattern(FcPattern* pattern) {
+    int fcweight = get_int(pattern, FC_WEIGHT, FC_WEIGHT_REGULAR);
+    int fcslant = get_int(pattern, FC_SLANT, FC_SLANT_ROMAN);
+    return (SkTypeface::Style)((fcweight >= FC_WEIGHT_BOLD ? SkTypeface::kBold : 0) |
+                                (fcslant > FC_SLANT_ROMAN ? SkTypeface::kItalic : 0));
+}
+
+class SkTypeface_stream : public SkTypeface_FreeType {
+public:
+    /** @param stream does not ownership of the reference, does take ownership of the stream. */

[mtklein, 2014/07/30 19:43:37]

does not _take_ ownership?

[bungeman-skia, 2014/08/08 21:45:24]

Done.

+    SkTypeface_stream(SkTypeface::Style style, bool fixedWidth, int ttcIndex, SkStreamAsset* stream)
+        : INHERITED(style, SkTypefaceCache::NewFontID(), fixedWidth)
+        , fStream(SkRef(stream))
+        , fIndex(ttcIndex)
+    { };
+
+    virtual void onGetFontDescriptor(SkFontDescriptor* desc, bool* serialize) const SK_OVERRIDE {
+        desc->setStyle(this->style());
+        *serialize = true;
+    }
+
+    virtual SkStream* onOpenStream(int* ttcIndex) const SK_OVERRIDE {
+        *ttcIndex = fIndex;
+        return fStream->duplicate();
+    }
+
+private:
+    SkAutoTUnref<SkStreamAsset> fStream;
+    int fIndex;
+
+    typedef SkTypeface_FreeType INHERITED;
+};
+
+class SkTypeface_fontconfig : public SkTypeface_FreeType {
+public:
+    /** @param pattern takes ownership of the reference. */
+    static SkTypeface_fontconfig* Create(FcPattern* pattern) {
+        return SkNEW_ARGS(SkTypeface_fontconfig, (pattern));
+    }
+    mutable SkAutoFcPattern fPattern;
+
+    virtual void onGetFontDescriptor(SkFontDescriptor* desc, bool* serialize) const SK_OVERRIDE {
+        FCLocker lock;
+        desc->setFamilyName(get_string(fPattern, FC_FAMILY));
+        desc->setFontFileName(get_string(fPattern, FC_FILE));
+        desc->setFullName(get_string(fPattern, FC_FULLNAME));
+        desc->setPostscriptName(get_string(fPattern, FC_POSTSCRIPT_NAME));
+        desc->setStyle(this->style());
+        *serialize = false;
+    }
+
+    virtual SkStream* onOpenStream(int* ttcIndex) const SK_OVERRIDE {
+        FCLocker lock;
+        *ttcIndex = get_int(fPattern, FC_INDEX, 0);
+        return SkStream::NewFromFile(get_string(fPattern, FC_FILE));
+    }
+
+    virtual ~SkTypeface_fontconfig() {
+        // Hold the lock while unrefing the pattern.
+        FCLocker lock;
+        fPattern.reset();
+    }
+
+private:
+    /** @param pattern takes ownership of the reference. */
+    SkTypeface_fontconfig(FcPattern* pattern)
+        : INHERITED(sktypefacestyle_from_fcpattern(pattern),
+                    SkTypefaceCache::NewFontID(),
+                    FC_PROPORTIONAL != get_int(pattern, FC_SPACING, FC_PROPORTIONAL))
+        , fPattern(pattern)
+    { };
+
+    typedef SkTypeface_FreeType INHERITED;
+};
+
+class SkFontMgr_fontconfig : public SkFontMgr {
+    mutable SkAutoFcConfig fFC;
+    SkAutoTUnref<SkDataTable> fFamilyNames;
+
+    class StyleSet : public SkFontStyleSet {
+    public:
+        /** @param parent does not take ownership of the reference.
+         *  @param fontSet takes ownership of the reference.
+         */
+        StyleSet(const SkFontMgr_fontconfig* parent, FcFontSet* fontSet)
+            : fFontMgr(SkRef(parent)), fFontSet(fontSet)
+        { }
+
+        virtual ~StyleSet() {
+            // Hold the lock while unrefing the font set.
+            FCLocker lock;
+            fFontSet.reset();
+        }
+
+        virtual int count() SK_OVERRIDE { return fFontSet->nfont; }
+
+        virtual void getStyle(int index, SkFontStyle* style, SkString* styleName) SK_OVERRIDE {
+            if (index < 0 || fFontSet->nfont <= index) {
+                return;
+            }
+
+            FCLocker lock;
+            if (style) {
+                *style = skfontstyle_from_fcpattern(fFontSet->fonts[index]);
+            }
+            if (styleName) {
+                *styleName = get_string(fFontSet->fonts[index], FC_STYLE);
+            }
+        }
+
+        virtual SkTypeface* createTypeface(int index) SK_OVERRIDE {
+            FCLocker lock;
+
+            FcPattern* match = fFontSet->fonts[index];
+            return fFontMgr->createTypefaceFromFcPattern(match);
+        }
+
+        virtual SkTypeface* matchStyle(const SkFontStyle& style) SK_OVERRIDE {
+            FCLocker lock;
+
+            SkAutoFcPattern pattern(FcPatternCreate());
+            if (NULL == pattern) {
+                return NULL;
+            }
+
+            fcpattern_from_skfontstyle(style, pattern);
+            FcConfigSubstitute(fFontMgr->fFC, pattern, FcMatchPattern);
+            FcDefaultSubstitute(pattern);
+
+            FcResult result;
+            FcFontSet* fontSets[1] = { fFontSet };
+            SkAutoFcPattern match(FcFontSetMatch(fFontMgr->fFC,
+                                                 fontSets, SK_ARRAY_COUNT(fontSets),
+                                                 pattern, &result));
+            if (NULL == match) {
+                return NULL;
+            }
+
+            return fFontMgr->createTypefaceFromFcPattern(match);
+        }
+
+    private:
+        SkAutoTUnref<const SkFontMgr_fontconfig> fFontMgr;
+        SkAutoFcFontSet fFontSet;
+    };
+
+    static bool FindName(const SkTDArray<const char*>& list, const char* str) {
+        int count = list.count();
+        for (int i = 0; i < count; ++i) {
+            if (!strcmp(list[i], str)) {
+                return true;
+            }
+        }
+        return false;
+    }
+
+    static SkDataTable* GetFamilyNames(FcConfig* fcconfig) {
+        FCLocker lock;
+
+        SkTDArray<const char*> names;
+        SkTDArray<size_t> sizes;
+
+        static const FcSetName fcNameSet[] = { FcSetSystem, FcSetApplication };
+        for (int setIndex = 0; setIndex < (int)SK_ARRAY_COUNT(fcNameSet); ++setIndex) {
+            // Return value of FcConfigGetFonts must not be destroyed.
+            FcFontSet* allFonts(FcConfigGetFonts(fcconfig, fcNameSet[setIndex]));
+            if (NULL == allFonts) {
+                continue;
+            }
+
+            for (int fontIndex = 0; fontIndex < allFonts->nfont; ++fontIndex) {
+                FcPattern* current = allFonts->fonts[fontIndex];
+                for (int id = 0; ; ++id) {
+                    FcChar8* fcFamilyName;
+                    FcResult result = FcPatternGetString(current, FC_FAMILY, id, &fcFamilyName);
+                    if (FcResultNoId == result) {
+                        break;
+                    }
+                    if (FcResultMatch != result) {
+                        continue;
+                    }
+                    const char* familyName = reinterpret_cast<const char*>(fcFamilyName);
+                    if (familyName && !FindName(names, familyName)) {
+                        *names.append() = familyName;
+                        *sizes.append() = strlen(familyName) + 1;
+                    }
+                }
+            }
+        }
+
+        return SkDataTable::NewCopyArrays((void const *const *)names.begin(),
+                                          sizes.begin(), names.count());
+    }
+
+    static bool FindByFcPattern(SkTypeface* cached, SkTypeface::Style, void* ctx) {
+        SkTypeface_fontconfig* cshFace = static_cast<SkTypeface_fontconfig*>(cached);
+        FcPattern* ctxPattern = static_cast<FcPattern*>(ctx);
+        return FcTrue == FcPatternEqual(cshFace->fPattern, ctxPattern);
+    }
+
+    mutable SkMutex fTFCacheMutex;
+    mutable SkTypefaceCache fTFCache;
+    /** Creates a typeface using a typeface cache.
+     *  @param pattern a complete pattern from FcFontRenderPrepare.
+     */
+    SkTypeface* createTypefaceFromFcPattern(FcPattern* pattern) const {
+        FCLocker::AssertHeld();
+        SkAutoMutexAcquire ama(fTFCacheMutex);
+        SkTypeface* face = fTFCache.findByProcAndRef(FindByFcPattern, pattern);
+        if (NULL == face) {
+            FcPatternReference(pattern);
+            face = SkTypeface_fontconfig::Create(pattern);
+            if (face) {
+                fTFCache.add(face, SkTypeface::kNormal, true);
+            }
+        }
+        return face;
+    }
+
+public:
+    SkFontMgr_fontconfig()
+        : fFC(FcInitLoadConfigAndFonts())
+        , fFamilyNames(GetFamilyNames(fFC)) { }
+
+    /** Takes control of the reference to 'config'. */
+    explicit SkFontMgr_fontconfig(FcConfig* config)
+        : fFC(config)
+        , fFamilyNames(GetFamilyNames(fFC)) { }
+
+    virtual ~SkFontMgr_fontconfig() {
+        // Hold the lock while unrefing the config.
+        FCLocker lock;
+        fFC.reset();
+    }
+
+protected:
+    virtual int onCountFamilies() const SK_OVERRIDE {
+        return fFamilyNames->count();
+    }
+
+    virtual void onGetFamilyName(int index, SkString* familyName) const SK_OVERRIDE {
+        familyName->set(fFamilyNames->atStr(index));
+    }
+
+    virtual SkFontStyleSet* onCreateStyleSet(int index) const SK_OVERRIDE {
+        return this->onMatchFamily(fFamilyNames->atStr(index));
+    }
+
+    /** True if any string object value in the font is the same
+     *         as a string object value in the pattern.
+     */
+    static bool AnyMatching(FcPattern* font, FcPattern* pattern, const char* object) {
+        FcChar8* fontString;
+        FcChar8* patternString;
+        FcResult result;
+        // Set an arbitrary limit on the number of pattern object values to consider.
+        // TODO: re-write this to avoid N*M
+        static const int maxId = 16;
+        for (int patternId = 0; patternId < maxId; ++patternId) {
+            result = FcPatternGetString(pattern, object, patternId, &patternString);
+            if (FcResultNoId == result) {
+                break;
+            }
+            if (FcResultMatch != result) {
+                continue;
+            }
+            for (int fontId = 0; fontId < maxId; ++fontId) {
+                result = FcPatternGetString(font, object, fontId, &fontString);
+                if (FcResultNoId == result) {
+                    break;
+                }
+                if (FcResultMatch != result) {
+                    continue;
+                }
+                if (0 == FcStrCmpIgnoreCase(patternString, fontString)) {
+                    return true;
+                }
+            }
+        }
+        return false;
+    }
+
+    static bool ValidPattern(FcPattern* pattern) {
+        // FontConfig can return fonts which are unreadable.
+        const char* filename = get_string(pattern, FC_FILE, NULL);
+        if (NULL == filename) {
+            return false;
+        }
+        return sk_exists(filename, kRead_SkFILE_Flag);
+    }
+
+    static bool FontMatches(FcPattern* font, FcPattern* pattern) {
+        return ValidPattern(font) && AnyMatching(font, pattern, FC_FAMILY);
+    }
+
+    virtual SkFontStyleSet* onMatchFamily(const char familyName[]) const SK_OVERRIDE {
+        FCLocker lock;
+
+        SkAutoFcPattern pattern(FcPatternCreate());
+        if (NULL == pattern) {
+            return NULL;
+        }
+
+        FcPatternAddString(pattern, FC_FAMILY, (FcChar8*)familyName);
+        FcConfigSubstitute(fFC, pattern, FcMatchPattern);
+        FcDefaultSubstitute(pattern);
+
+        FcPattern* matchPattern;
+        SkAutoFcPattern strongPattern(NULL);
+        if (familyName) {
+            strongPattern.reset(FcPatternDuplicate(pattern));
+            remove_weak(strongPattern, FC_FAMILY);
+            matchPattern = strongPattern;
+        } else {
+            matchPattern = pattern;
+        }
+
+        SkAutoFcFontSet matches(FcFontSetCreate());
+        // TODO: Some families have 'duplicates' due to symbolic links.
+        // The patterns are exactly the same except for the FC_FILE.
+        // It should be possible to collapse these patterns by normalizing.
+        static const FcSetName fcNameSet[] = { FcSetSystem, FcSetApplication };
+        for (int setIndex = 0; setIndex < (int)SK_ARRAY_COUNT(fcNameSet); ++setIndex) {
+            // Return value of FcConfigGetFonts must not be destroyed.
+            FcFontSet* allFonts(FcConfigGetFonts(fFC, fcNameSet[setIndex]));
+            if (NULL == allFonts) {
+                continue;
+            }
+
+            for (int fontIndex = 0; fontIndex < allFonts->nfont; ++fontIndex) {
+                if (FontMatches(allFonts->fonts[fontIndex], matchPattern)) {
+                    FcFontSetAdd(matches,
+                                 FcFontRenderPrepare(fFC, pattern, allFonts->fonts[fontIndex]));
+                }
+            }
+        }
+
+        return SkNEW_ARGS(StyleSet, (this, matches.detach()));
+    }
+
+    virtual SkTypeface* onMatchFamilyStyle(const char familyName[],
+                                           const SkFontStyle& style) const SK_OVERRIDE
+    {
+        FCLocker lock;
+
+        SkAutoFcPattern pattern(FcPatternCreate());
+        if (NULL == pattern) {
+            return NULL;
+        }
+
+        FcPatternAddString(pattern, FC_FAMILY, (FcChar8*)familyName);
+        fcpattern_from_skfontstyle(style, pattern);
+        FcConfigSubstitute(fFC, pattern, FcMatchPattern);
+        FcDefaultSubstitute(pattern);
+
+        // We really want to match strong (prefered) and same (acceptable) only here.
+        // If a family name was specified, assume that any weak matches after the last strong match
+        // are weak (default) and ignore them.
+        // The reason for is that after substitution the pattern for 'sans-serif' looks like
+        // "wwwwwwwwwwwwwwswww" where there are many weak but preferred names, followed by defaults.
+        // So it is possible to have weakly matching but preferred names.
+        // In aliases, bindings are weak by default, so this is easy and common.
+        // If no family name was specified, we'll probably only get weak matches, but that's ok.
+        FcPattern* matchPattern;
+        SkAutoFcPattern strongPattern(NULL);
+        if (familyName) {
+            strongPattern.reset(FcPatternDuplicate(pattern));
+            remove_weak(strongPattern, FC_FAMILY);
+            matchPattern = strongPattern;
+        } else {
+            matchPattern = pattern;
+        }
+
+        FcResult result;
+        SkAutoFcPattern match(FcFontMatch(fFC, pattern, &result));
+        if (NULL == match || !FontMatches(match, matchPattern)) {
+            return NULL;
+        }
+
+        return createTypefaceFromFcPattern(match);
+    }
+
+    virtual SkTypeface* onMatchFaceStyle(const SkTypeface* typeface,
+                                         const SkFontStyle& style) const SK_OVERRIDE
+    {
+        //TODO: should the SkTypeface_fontconfig know its family?
+        const SkTypeface_fontconfig* fcTypeface =
+            static_cast<const SkTypeface_fontconfig*>(typeface);
+        return this->matchFamilyStyle(get_string(fcTypeface->fPattern, FC_FAMILY), style);
+    }
+
+    /** @param stream does not take ownership of the reference. */
+    virtual SkTypeface* onCreateFromStream(SkStream* stream, int ttcIndex) const SK_OVERRIDE {
+        const size_t length = stream->getLength();
+        if (length <= 0 || (1u << 30) < length) {
+            return NULL;
+        }
+
+        SkTypeface::Style style = SkTypeface::kNormal;
+        bool isFixedWidth = false;
+        if (!SkTypeface_FreeType::ScanFont(stream, ttcIndex, NULL, &style, &isFixedWidth)) {
+            return NULL;
+        }
+
+        return SkNEW_ARGS(SkTypeface_stream, (style, isFixedWidth, ttcIndex,
+                                              static_cast<SkStreamAsset*>(stream)));
+    }
+
+    virtual SkTypeface* onCreateFromData(SkData* data, int ttcIndex) const SK_OVERRIDE {
+        SkAutoTUnref<SkStreamAsset> stream(SkNEW_ARGS(SkMemoryStream, (data)));
+        return this->createFromStream(stream, ttcIndex);
+    }
+
+    virtual SkTypeface* onCreateFromFile(const char path[], int ttcIndex) const SK_OVERRIDE {
+        SkAutoTUnref<SkStreamAsset> stream(SkStream::NewFromFile(path));
+        return this->createFromStream(stream, ttcIndex);
+    }
+
+    virtual SkTypeface* onLegacyCreateTypeface(const char familyName[],
+                                               unsigned styleBits) const SK_OVERRIDE {
+        bool bold = styleBits & SkTypeface::kBold;
+        bool italic = styleBits & SkTypeface::kItalic;
+        SkFontStyle style = SkFontStyle(bold ? SkFontStyle::kBold_Weight
+                                             : SkFontStyle::kNormal_Weight,
+                                        SkFontStyle::kNormal_Width,
+                                        italic ? SkFontStyle::kItalic_Slant
+                                               : SkFontStyle::kUpright_Slant);
+        SkAutoTUnref<SkTypeface> typeface(this->matchFamilyStyle(familyName, style));
+        if (NULL != typeface.get()) {
+            return typeface.detach();
+        }
+
+        return this->matchFamilyStyle(NULL, style);
+    }
+};
+
+SkFontMgr* SkFontMgr::Factory() {
+    return SkNEW(SkFontMgr_fontconfig);
+}