Make GrGLProgramDesc's key variable length by compacting the effect key array

src/gpu/gl/GrGpuGL.h

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 
 
 #ifndef GrGpuGL_DEFINED
@@ skipping 159 matching lines @@
 
     static bool BlendCoeffReferencesConstant(GrBlendCoeff coeff);
 
     class ProgramCache : public ::GrNoncopyable {
     public:
         ProgramCache(const GrGLContext& gl);
         ~ProgramCache();
 
         void abandon();
         GrGLProgram* getProgram(const GrGLProgramDesc& desc, const GrEffectStage* stages[]);
+
     private:
         enum {
-            kKeySize = sizeof(GrGLProgramDesc),
             // We may actually have kMaxEntries+1 shaders in the GL context because we create a new
             // shader before evicting from the cache.
-            kMaxEntries = 32
+            kMaxEntries = 32,
+            kHashBits = 6,
         };
 
-        class Entry;
-        // The value of the hash key is based on the ProgramDesc.
-        typedef GrTBinHashKey<Entry, kKeySize> ProgramHashKey;
+        struct Entry;
 
-        class Entry : public ::GrNoncopyable {
-        public:
-            Entry() : fProgram(NULL), fLRUStamp(0) {}
-            Entry& operator = (const Entry& entry) {
-                GrSafeRef(entry.fProgram.get());
-                fProgram.reset(entry.fProgram.get());
-                fKey = entry.fKey;
-                fLRUStamp = entry.fLRUStamp;
-                return *this;
-            }
-            int compare(const ProgramHashKey& key) const {
-                return fKey.compare(key);
-            }
+        struct ProgDescLess;
 
-        public:
-            SkAutoTUnref<GrGLProgram>   fProgram;
-            ProgramHashKey              fKey;
-            unsigned int                fLRUStamp; // Move outside entry?
-        };
+        // binary search for entry matching desc. returns index into fEntries that matches desc or ~
+        // of the index of where it should be inserted.
+        int search(const GrGLProgramDesc& desc) const;
 
-        GrTHashTable<Entry, ProgramHashKey, 8> fHashCache;
+        // sorted array of all the entries
+        Entry*                      fEntries[kMaxEntries];
+        // hash table based on lowest kHashBits bits of the program key. Used to avoid binary
+        // searching fEntries.
+        Entry*                      fHashTable[1 << kHashBits];
 
-        Entry                       fEntries[kMaxEntries];
         int                         fCount;
         unsigned int                fCurrLRUStamp;
         const GrGLContext&          fGL;
 #ifdef PROGRAM_CACHE_STATS
         int                         fTotalRequests;
         int                         fCacheMisses;
+        int                         fHashMisses; // cache hit but hash table missed
 #endif
     };
 
     // sets the matrix for path stenciling (uses the GL fixed pipe matrices)
     void flushPathStencilMatrix();
 
     // flushes dithering, color-mask, and face culling stat
     void flushMiscFixedFunctionState();
 
     // flushes the scissor. see the note on flushBoundTextureAndParams about
@@ skipping 207 matching lines @@
     ///@}
 
     // we record what stencil format worked last time to hopefully exit early
     // from our loop that tries stencil formats and calls check fb status.
     int fLastSuccessfulStencilFmtIdx;
 
     typedef GrGpu INHERITED;
 };
 
 #endif