Clean up SkFontConfigInterface implementation.

src/fonts/SkFontMgr_fontconfig.cpp

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkFontConfigInterface.h"
 #include "SkFontConfigTypeface.h"
+#include "SkFontDescriptor.h"
 #include "SkFontMgr.h"
 #include "SkFontStyle.h"
-#include "SkMath.h"
 #include "SkMutex.h"
 #include "SkString.h"
-#include "SkTDArray.h"
+#include "SkTypeface.h"
+#include "SkTypefaceCache.h"
+#include "SkResourceCache.h"
 
-// for now we pull these in directly. eventually we will solely rely on the
-// SkFontConfigInterface instance.
-#include <fontconfig/fontconfig.h>
-#include <unistd.h>
+SkStreamAsset* SkTypeface_FCI::onOpenStream(int* ttcIndex) const {
+    *ttcIndex =  this->getIdentity().fTTCIndex;
 
-namespace {
-
-// Fontconfig is not threadsafe before 2.10.91.  Before that, we lock with a global mutex.
-// See skia:1497 for background.
-SK_DECLARE_STATIC_MUTEX(gFCMutex);
-static bool gFCSafeToUse;
-
-struct FCLocker {
-    FCLocker() {
-        if (FcGetVersion() < 21091) {  // We assume FcGetVersion() has always been thread safe.
-            gFCMutex.acquire();
-            fUnlock = true;
-        } else {
-            fUnlock = false;
-        }
-        gFCSafeToUse = true;
+    SkStreamAsset* stream = this->getLocalStream();
+    if (stream) {
+        return stream->duplicate();
     }
 
-    ~FCLocker() {
-        if (fUnlock) {
-            gFCSafeToUse = false;
-            gFCMutex.release();
+    return fFCI->openStream(this->getIdentity());
+}
+
+void SkTypeface_FCI::onGetFontDescriptor(SkFontDescriptor* desc, bool* isLocalStream) const {
+    SkString name;
+    this->getFamilyName(&name);
+    desc->setFamilyName(name.c_str());
+    *isLocalStream = SkToBool(this->getLocalStream());
+}
+
+///////////////////////////////////////////////////////////////////////////////
+
+class SkFontStyleSet_FCI : public SkFontStyleSet {
+public:
+    SkFontStyleSet_FCI() {}
+
+    int count() override { return 0; }
+    void getStyle(int index, SkFontStyle*, SkString* style) override { SkASSERT(false); }
+    SkTypeface* createTypeface(int index) override { SkASSERT(false); return nullptr; }
+    SkTypeface* matchStyle(const SkFontStyle& pattern) override { return nullptr; }
+};
+
+///////////////////////////////////////////////////////////////////////////////
+
+class SkFontRequestCache {
+public:
+    struct Request : public SkResourceCache::Key {
+    private:
+        Request(const char* name, size_t nameLen, const SkFontStyle& style) : fStyle(style) {
+            /** Pointer to just after the last field of this class. */
+            char* content = const_cast<char*>(SkTAfter<const char>(&this->fStyle));
+
+            // No holes.
+            SkASSERT(SkTAddOffset<char>(this, sizeof(SkResourceCache::Key) + keySize) == content);
+
+            // Has a size divisible by size of uint32_t.
+            SkASSERT((content - reinterpret_cast<char*>(this)) % sizeof(uint32_t) == 0);
+
+            size_t contentLen = SkAlign4(nameLen);
+            sk_careful_memcpy(content, name, nameLen);
+            sk_bzero(content + nameLen, contentLen - nameLen);
+            this->init(nullptr, 0, keySize + contentLen);
         }
-    }
+        const SkFontStyle fStyle;
+        /** The sum of the sizes of the fields of this class. */
+        static const size_t keySize = sizeof(fStyle);
+
+    public:
+        static Request* Create(const char* name, const SkFontStyle& style) {
+            size_t nameLen = name ? strlen(name) : 0;
+            size_t contentLen = SkAlign4(nameLen);
+            char* storage = new char[sizeof(Request) + contentLen];
+            return new (storage) Request(name, nameLen, style);
+        }
+        void operator delete(void* storage) {
+            delete[] reinterpret_cast<char*>(storage);
+        }
+    };
+
 
 private:
-    bool fUnlock;
+    struct Result : public SkResourceCache::Rec {
+        Result(Request* request, SkTypeface* typeface)
+            : fRequest(request)
+            , fFace(SkSafeRef(typeface)) {}
+        Result(Result&&) = default;
+        Result& operator=(Result&&) = default;
+
+        const Key& getKey() const override { return *fRequest; }
+        size_t bytesUsed() const override { return fRequest->size() + sizeof(fFace); }
+        const char* getCategory() const override { return "request_cache"; }
+        SkDiscardableMemory* diagnostic_only_getDiscardable() const override { return nullptr; }
+
+        SkAutoTDelete<Request> fRequest;
+        SkAutoTUnref<SkTypeface> fFace;
+    };
+
+    SkResourceCache fCachedResults;
+
+public:
+    SkFontRequestCache(size_t maxSize) : fCachedResults(maxSize) {}
+
+    /** Takes ownership of request. It will be deleted when no longer needed. */
+    void add(SkTypeface* face, Request* request) {
+        fCachedResults.add(new Result(request, face));
+    }
+    /** Does not take ownership of request. */
+    SkTypeface* findAndRef(Request* request) {
+        SkTypeface* face = nullptr;
+        fCachedResults.find(*request, [](const SkResourceCache::Rec& rec, void* context) -> bool {
+            const Result& result = static_cast<const Result&>(rec);
+            SkTypeface** face = static_cast<SkTypeface**>(context);
+
+            *face = result.fFace;
+            return true;
+        }, &face);
+        return SkSafeRef(face);
+    }
 };
 
-} // namespace
+///////////////////////////////////////////////////////////////////////////////
 
-// borrow this global from SkFontHost_fontconfig. eventually that file should
-// go away, and be replaced with this one.
-extern SkFontConfigInterface* SkFontHost_fontconfig_ref_global();
-static SkFontConfigInterface* RefFCI() {
-    return SkFontHost_fontconfig_ref_global();
+static bool find_by_FontIdentity(SkTypeface* cachedTypeface, void* ctx) {
+    typedef SkFontConfigInterface::FontIdentity FontIdentity;
+    SkTypeface_FCI* cachedFCTypeface = static_cast<SkTypeface_FCI*>(cachedTypeface);
+    FontIdentity* identity = static_cast<FontIdentity*>(ctx);
+
+    return cachedFCTypeface->getIdentity() == *identity;
 }
 
-// look for the last substring after a '/' and return that, or return null.
-static const char* find_just_name(const char* str) {
-    const char* last = strrchr(str, '/');
-    return last ? last + 1 : nullptr;
-}
+///////////////////////////////////////////////////////////////////////////////
 
-static bool is_lower(char c) {
-    return c >= 'a' && c <= 'z';
-}
-
-static int get_int(FcPattern* pattern, const char field[]) {
-    SkASSERT(gFCSafeToUse);
-    int value;
-    if (FcPatternGetInteger(pattern, field, 0, &value) != FcResultMatch) {
-        value = SK_MinS32;
-    }
-    return value;
-}
-
-static const char* get_name(FcPattern* pattern, const char field[]) {
-    SkASSERT(gFCSafeToUse);
-    const char* name;
-    if (FcPatternGetString(pattern, field, 0, (FcChar8**)&name) != FcResultMatch) {
-        name = "";
-    }
-    return name;
-}
-
-static bool valid_pattern(FcPattern* pattern) {
-    SkASSERT(gFCSafeToUse);
-    FcBool is_scalable;
-    if (FcPatternGetBool(pattern, FC_SCALABLE, 0, &is_scalable) != FcResultMatch || !is_scalable) {
-        return false;
-    }
-
-    // fontconfig can also return fonts which are unreadable
-    const char* c_filename = get_name(pattern, FC_FILE);
-    if (0 == *c_filename) {
-        return false;
-    }
-    if (access(c_filename, R_OK) != 0) {
-        return false;
-    }
-    return true;
-}
-
-static bool match_name(FcPattern* pattern, const char family_name[]) {
-    return !strcasecmp(family_name, get_name(pattern, FC_FAMILY));
-}
-
-static FcPattern** MatchFont(FcFontSet* font_set,
-                             const char post_config_family[],
-                             int* count) {
-  // Older versions of fontconfig have a bug where they cannot select
-  // only scalable fonts so we have to manually filter the results.
-
-    FcPattern** iter = font_set->fonts;
-    FcPattern** stop = iter + font_set->nfont;
-    // find the first good match
-    for (; iter < stop; ++iter) {
-        if (valid_pattern(*iter)) {
-            break;
-        }
-    }
-
-    if (iter == stop || !match_name(*iter, post_config_family)) {
-        return nullptr;
-    }
-
-    FcPattern** firstIter = iter++;
-    for (; iter < stop; ++iter) {
-        if (!valid_pattern(*iter) || !match_name(*iter, post_config_family)) {
-            break;
-        }
-    }
-
-    *count = iter - firstIter;
-    return firstIter;
-}
-
-class SkFontStyleSet_FC : public SkFontStyleSet {
-public:
-    SkFontStyleSet_FC(FcPattern** matches, int count);
-    virtual ~SkFontStyleSet_FC();
-
-    int count() override { return fRecCount; }
-    void getStyle(int index, SkFontStyle*, SkString* style) override;
-    SkTypeface* createTypeface(int index) override;
-    SkTypeface* matchStyle(const SkFontStyle& pattern) override;
-
-private:
-    struct Rec {
-        SkString    fStyleName;
-        SkString    fFileName;
-        SkFontStyle fStyle;
-    };
-    Rec* fRecs;
-    int  fRecCount;
-};
-
-static int map_range(int value,
-                     int old_min, int old_max, int new_min, int 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);
-}
-
-static SkFontStyle make_fontconfig_style(FcPattern* match) {
-    int weight = get_int(match, FC_WEIGHT);
-    int width = get_int(match, FC_WIDTH);
-    int fcSlant = get_int(match, FC_SLANT);
-
-    // fontconfig weight seems to be 0..200 or so, so we remap it here
-    weight = map_range(weight, 0, 80, 0, 400);
-    width = map_range(width, 0, 200, 0, 9);
-    SkFontStyle::Slant skSlant = SkFontStyle::kUpright_Slant;
-    switch (fcSlant) {
-        case FC_SLANT_ROMAN:   skSlant = SkFontStyle::kUpright_Slant; break;
-        case FC_SLANT_ITALIC : skSlant = SkFontStyle::kItalic_Slant ; break;
-        case FC_SLANT_OBLIQUE: skSlant = SkFontStyle::kOblique_Slant; break;
-        default: SkASSERT(false); break;
-    }
-    return SkFontStyle(weight, width, skSlant);
-}
-
-SkFontStyleSet_FC::SkFontStyleSet_FC(FcPattern** matches, int count) {
-    fRecCount = count;
-    fRecs = new Rec[count];
-    for (int i = 0; i < count; ++i) {
-        fRecs[i].fStyleName.set(get_name(matches[i], FC_STYLE));
-        fRecs[i].fFileName.set(get_name(matches[i], FC_FILE));
-        fRecs[i].fStyle = make_fontconfig_style(matches[i]);
-    }
-}
-
-SkFontStyleSet_FC::~SkFontStyleSet_FC() { delete[] fRecs; }
-
-void SkFontStyleSet_FC::getStyle(int index, SkFontStyle* style,
-                                 SkString* styleName) {
-    SkASSERT((unsigned)index < (unsigned)fRecCount);
-    if (style) {
-        *style = fRecs[index].fStyle;
-    }
-    if (styleName) {
-        *styleName = fRecs[index].fStyleName;
-    }
-}
-
-SkTypeface* SkFontStyleSet_FC::createTypeface(int index) {
-    return nullptr;
-}
-
-SkTypeface* SkFontStyleSet_FC::matchStyle(const SkFontStyle& pattern) {
-    return nullptr;
-}
-
-class SkFontMgr_fontconfig : public SkFontMgr {
+class SkFontMgr_FCI : public SkFontMgr {
     SkAutoTUnref<SkFontConfigInterface> fFCI;
-    SkDataTable* fFamilyNames;
+    SkAutoTUnref<SkDataTable> fFamilyNames;
     SkTypeface_FreeType::Scanner fScanner;
 
+    mutable SkMutex fMutex;
+    mutable SkTypefaceCache fTFCache;
+
+    // The value of maxSize here is a compromise between cache hits and cache size.
+    // See https://crbug.com/424082#63 for reason for current size.
+    static const size_t kMaxSize = 1 << 15;
+    mutable SkFontRequestCache fCache;
+
 public:
-    SkFontMgr_fontconfig(SkFontConfigInterface* fci)
+    SkFontMgr_FCI(SkFontConfigInterface* fci)
         : fFCI(fci)
-        , fFamilyNames(fFCI->getFamilyNames()) {}
-
-    virtual ~SkFontMgr_fontconfig() {
-        SkSafeUnref(fFamilyNames);
-    }
+        , fFamilyNames(fFCI->getFamilyNames())
+        , fCache(kMaxSize)
+    {}
 
 protected:
     int onCountFamilies() const override {
         return fFamilyNames->count();
     }
 
     void onGetFamilyName(int index, SkString* familyName) const override {
         familyName->set(fFamilyNames->atStr(index));
     }
 
     SkFontStyleSet* onCreateStyleSet(int index) const override {
         return this->onMatchFamily(fFamilyNames->atStr(index));
     }
 
     SkFontStyleSet* onMatchFamily(const char familyName[]) const override {
-        FCLocker lock;
-
-        FcPattern* pattern = FcPatternCreate();
-
-        FcPatternAddString(pattern, FC_FAMILY, (FcChar8*)familyName);
-#if 0
-        FcPatternAddBool(pattern, FC_SCALABLE, FcTrue);
-#endif
-        FcConfigSubstitute(nullptr, pattern, FcMatchPattern);
-        FcDefaultSubstitute(pattern);
-
-        const char* post_config_family = get_name(pattern, FC_FAMILY);
-
-        FcResult result;
-        FcFontSet* font_set = FcFontSort(0, pattern, 0, 0, &result);
-        if (!font_set) {
-            FcPatternDestroy(pattern);
-            return nullptr;
-        }
-
-        int count;
-        FcPattern** match = MatchFont(font_set, post_config_family, &count);
-        if (!match) {
-            FcPatternDestroy(pattern);
-            FcFontSetDestroy(font_set);
-            return nullptr;
-        }
-
-        FcPatternDestroy(pattern);
-
-        SkTDArray<FcPattern*> trimmedMatches;
-        for (int i = 0; i < count; ++i) {
-            const char* justName = find_just_name(get_name(match[i], FC_FILE));
-            if (!is_lower(*justName)) {
-                *trimmedMatches.append() = match[i];
-            }
-        }
-
-        SkFontStyleSet_FC* sset =
-                new SkFontStyleSet_FC(trimmedMatches.begin(), trimmedMatches.count());
-        return sset;
+        return new SkFontStyleSet_FCI();
     }
 
     SkTypeface* onMatchFamilyStyle(const char familyName[],
                                    const SkFontStyle&) const override { return nullptr; }
     SkTypeface* onMatchFamilyStyleCharacter(const char familyName[], const SkFontStyle&,
                                             const char* bcp47[], int bcp47Count,
                                             SkUnichar character) const override {
         return nullptr;
     }
     SkTypeface* onMatchFaceStyle(const SkTypeface*,
@@ skipping 11 matching lines @@
             return nullptr;  // don't accept too large fonts (>= 1GB) for safety.
         }
 
         // TODO should the caller give us the style or should we get it from freetype?
         SkFontStyle style;
         bool isFixedWidth = false;
         if (!fScanner.scanFont(stream, 0, nullptr, &style, &isFixedWidth, nullptr)) {
             return nullptr;
         }
 
-        SkTypeface* face = FontConfigTypeface::Create(style, isFixedWidth, stream.release());
-        return face;
+        return SkTypeface_FCI::Create(style, isFixedWidth, stream.release(), ttcIndex);
     }
 
     SkTypeface* onCreateFromFile(const char path[], int ttcIndex) const override {
         SkAutoTDelete<SkStreamAsset> stream(SkStream::NewFromFile(path));
         return stream.get() ? this->createFromStream(stream.release(), ttcIndex) : nullptr;
     }
 
-    SkTypeface* onLegacyCreateTypeface(const char familyName[], SkFontStyle style) const override {
-        FCLocker lock;
-        return FontConfigTypeface::LegacyCreateTypeface(familyName, style);
+    SkTypeface* onLegacyCreateTypeface(const char requestedFamilyName[],
+                                       SkFontStyle requestedStyle) const override
+    {
+        SkAutoMutexAcquire ama(fMutex);
+
+        // Check if this request is already in the request cache.
+        using Request = SkFontRequestCache::Request;
+        SkAutoTDelete<Request> request(Request::Create(requestedFamilyName, requestedStyle));
+        SkTypeface* face = fCache.findAndRef(request);
+        if (face) {
+            return face;
+        }
+
+        SkFontConfigInterface::FontIdentity identity;
+        SkString outFamilyName;
+        SkFontStyle outStyle;
+        if (!fFCI->matchFamilyName(requestedFamilyName, requestedStyle,
+                                   &identity, &outFamilyName, &outStyle))
+        {
+            return nullptr;
+        }
+
+        // Check if a typeface with this FontIdentity is already in the FontIdentity cache.
+        face = fTFCache.findByProcAndRef(find_by_FontIdentity, &identity);
+        if (!face) {
+            face = SkTypeface_FCI::Create(fFCI, identity, outFamilyName, outStyle);
+            // Add this FontIdentity to the FontIdentity cache.
+            fTFCache.add(face);
+        }
+        // Add this request to the request cache.
+        fCache.add(face, request.release());
+
+        return face;
     }
 };
 
-SkFontMgr* SkFontMgr::Factory() {
-    SkFontConfigInterface* fci = RefFCI();
-    return fci ? new SkFontMgr_fontconfig(fci) : nullptr;
+SK_API SkFontMgr* SkFontMgr_New_FCI(SkFontConfigInterface* fci) {
+    SkASSERT(fci);
+    return new SkFontMgr_FCI(fci);
 }