Parallel cache - preliminary

src/core/SkGlyphCache.h

 /*
  * Copyright 2006 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be found in the LICENSE file.
  */
 
 #ifndef SkGlyphCache_DEFINED
 #define SkGlyphCache_DEFINED
 
 #include "SkBitmap.h"
 #include "SkChunkAlloc.h"
 #include "SkDescriptor.h"
 #include "SkGlyph.h"
+#include "SkMutex.h"
 #include "SkTHash.h"
 #include "SkScalerContext.h"
+#include "SkSharedMutex.h"
+#include "SkSpinlock.h"
 #include "SkTemplates.h"
 #include "SkTDArray.h"
 
 class SkPaint;
 class SkTraceMemoryDump;
 
 class SkGlyphCache_Globals;
 
 /** \class SkGlyphCache
 
@@ skipping 86 matching lines @@
     */
 
     //! If the proc is found, return true and set *dataPtr to its data
     bool getAuxProcData(void (*auxProc)(void*), void** dataPtr) const;
 
     //! Add a proc/data pair to the glyphcache. proc should be non-null
     void setAuxProc(void (*auxProc)(void*), void* auxData);
 
     SkScalerContext* getScalerContext() const { return fScalerContext; }
 
+    struct GlyphAndCache {
+        SkGlyphCache* cache;
+        const SkGlyph* glyph;
+    };
+
+    static void OnceFillInImage(GlyphAndCache gc);
+
+    static void OnceFillInPath(GlyphAndCache gc);
+
+    typedef bool (*VisitProc)(const SkGlyphCache*, void*);
+
     /** Find a matching cache entry, and call proc() with it. If none is found create a new one.
         If the proc() returns true, detach the cache and return it, otherwise leave it and return
         nullptr.
     */
     static SkGlyphCache* VisitCache(SkTypeface*, const SkDescriptor* desc,
-                                    bool (*proc)(const SkGlyphCache*, void*),
+                                    VisitProc proc,
                                     void* context);
 
     /** Given a strike that was returned by either VisitCache() or DetachCache() add it back into
         the global cache list (after which the caller should not reference it anymore.
     */
     static void AttachCache(SkGlyphCache*);
 
     /** Detach a strike from the global cache matching the specified descriptor. Once detached,
         it can be queried/modified by the current thread, and when finished, be reattached to the
         global cache with AttachCache(). While detached, if another request is made with the same
@@ skipping 36 matching lines @@
         void forget() {
             fCache = nullptr;
         }
     private:
         const SkGlyphCache* fCache;
     };
 
 private:
     friend class SkGlyphCache_Globals;
 
-    enum {
-        kHashBits           = 8,
-        kHashCount          = 1 << kHashBits,
-        kHashMask           = kHashCount - 1
-    };
-
     typedef uint32_t PackedGlyphID;    // glyph-index + subpixel-pos
     typedef uint32_t PackedUnicharID;  // unichar + subpixel-pos
 
     struct CharGlyphRec {
-        PackedUnicharID    fPackedUnicharID;
-        PackedGlyphID      fPackedGlyphID;
+        class HashTraits {
+        public:
+            static PackedUnicharID GetKey(const CharGlyphRec& rec) {
+                return rec.fPackedUnicharID;
+            }
+            static uint32_t Hash(PackedUnicharID unicharID) {
+                return SkChecksum::CheapMix(unicharID);
+            }
+        };
+        PackedUnicharID fPackedUnicharID;
+        PackedGlyphID fPackedGlyphID;
     };
 
     struct AuxProcRec {
         AuxProcRec* fNext;
         void (*fProc)(void*);
         void* fData;
     };
 
     // SkGlyphCache takes ownership of the scalercontext.
     SkGlyphCache(SkTypeface*, const SkDescriptor*, SkScalerContext*);
     ~SkGlyphCache();
 
+    // Increase the memory used keeping the cache and the global size in sync.
+    void increaseMemoryUsed(size_t used);
+
     // Return the SkGlyph* associated with MakeID. The id parameter is the
     // combined glyph/x/y id generated by MakeID. If it is just a glyph id
     // then x and y are assumed to be zero.
     SkGlyph* lookupByPackedGlyphID(PackedGlyphID packedGlyphID);
 
     // Return a SkGlyph* associated with unicode id and position x and y.
     SkGlyph* lookupByChar(SkUnichar id, SkFixed x = 0, SkFixed y = 0);
 
     // Return a new SkGlyph for the glyph ID and subpixel position id.
     SkGlyph* allocateNewGlyph(PackedGlyphID packedGlyphID);
 
+    // Add the full metrics to an existing glyph.
+    void addFullMetrics(SkGlyph* glyph);
+
     static bool DetachProc(const SkGlyphCache*, void*) { return true; }
 
+    CharGlyphRec PackedUnicharIDtoCharGlyphRec(PackedUnicharID packedUnicharID);
+
     // The id arg is a combined id generated by MakeID.
     CharGlyphRec* getCharGlyphRec(PackedUnicharID id);
 
-    void invokeAndRemoveAuxProcs();
-
     inline static SkGlyphCache* FindTail(SkGlyphCache* head);
 
+    // The following are protected by the SkGlyphCache_Globals fLock mutex.
+    // Note: the following fields are protected by a mutex in a different class.
     SkGlyphCache*          fNext;
     SkGlyphCache*          fPrev;
     SkDescriptor* const    fDesc;
-    SkScalerContext* const fScalerContext;
     SkPaint::FontMetrics   fFontMetrics;
+    int                    fRefCount;
 
+    // The following fields are protected by fMapMutex.
+    mutable SkSharedMutex fMapMutex;
     // Map from a combined GlyphID and sub-pixel position to a SkGlyph.
     SkTHashTable<SkGlyph, PackedGlyphID, SkGlyph::HashTraits> fGlyphMap;
-
     SkChunkAlloc           fGlyphAlloc;
-
-    SkAutoTArray<CharGlyphRec> fPackedUnicharIDToPackedGlyphID;
-
+    typedef SkTHashTable<CharGlyphRec, PackedUnicharID, CharGlyphRec::HashTraits>
+            PackedUnicharIDToPackedGlyphIDMap;
+    SkAutoTDelete<PackedUnicharIDToPackedGlyphIDMap> fPackedUnicharIDToPackedGlyphID;
     // used to track (approx) how much ram is tied-up in this cache
     size_t                 fMemoryUsed;
 
+    // The FScalerMutex protects the following fields. It is mainly used to ensure single-threaded
+    // access to the font scaler, but it also protects the fAuxProcList.
+    mutable SkMutex        fScalerMutex;
+    SkScalerContext* const fScalerContext;
     AuxProcRec*            fAuxProcList;
+
+    // BEWARE: Mutex ordering
+    // If you need to hold both fMapMutex and fScalerMutex then fMapMutex must be held first.
 };
 
 class SkAutoGlyphCacheBase {
 public:
     SkGlyphCache* getCache() const { return fCache; }
 
     void release() {
         if (fCache) {
             SkGlyphCache::AttachCache(fCache);
             fCache = nullptr;
@@ skipping 53 matching lines @@
                             const SkMatrix* matrix) {
         fCache = paint.detachCache(surfaceProps, matrix, true);
     }
 
 private:
     SkAutoGlyphCacheNoGamma() : SkAutoGlyphCacheBase() {}
 };
 #define SkAutoGlyphCacheNoGamma(...) SK_REQUIRE_LOCAL_VAR(SkAutoGlyphCacheNoGamma)
 
 #endif