Small cleanups to SkSmallAllocator

src/core/SkSmallAllocator.h

 /*
  * Copyright 2014 Google, Inc
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkSmallAllocator_DEFINED
 #define SkSmallAllocator_DEFINED
 
 #include "SkTDArray.h"
 #include "SkTypes.h"
 
-// Used by SkSmallAllocator to call the destructor for objects it has
-// allocated.
-template<typename T> void destroyT(void* ptr) {
-   static_cast<T*>(ptr)->~T();
-}
+#include <new>
 
 /*
  *  Template class for allocating small objects without additional heap memory
  *  allocations. kMaxObjects is a hard limit on the number of objects that can
  *  be allocated using this class. After that, attempts to create more objects
  *  with this class will assert and return nullptr.
  *  kTotalBytes is the total number of bytes provided for storage for all
  *  objects created by this allocator. If an object to be created is larger
  *  than the storage (minus storage already used), it will be allocated on the
  *  heap. This class's destructor will handle calling the destructor for each
@@ skipping 16 matching lines @@
             rec->fKillProc(rec->fObj);
             // Safe to do if fObj is in fStorage, since fHeapStorage will
             // point to nullptr.
             sk_free(rec->fHeapStorage);
         }
     }
 
     /*
      *  Create a new object of type T. Its lifetime will be handled by this
      *  SkSmallAllocator.
-     *  Each version behaves the same but takes a different number of
-     *  arguments.
      *  Note: If kMaxObjects have been created by this SkSmallAllocator, nullptr
      *  will be returned.
      */
-    template<typename T>
-    T* createT() {
+    template<typename T, typename... Args>
+    T* createT(const Args&... args) {
         void* buf = this->reserveT<T>();
         if (nullptr == buf) {
             return nullptr;
         }
-        new (buf) T;
-        return static_cast<T*>(buf);
-    }
-
-    template<typename T, typename A1> T* createT(const A1& a1) {
-        void* buf = this->reserveT<T>();
-        if (nullptr == buf) {
-            return nullptr;
-        }
-        new (buf) T(a1);
-        return static_cast<T*>(buf);
-    }
-
-    template<typename T, typename A1, typename A2>
-    T* createT(const A1& a1, const A2& a2) {
-        void* buf = this->reserveT<T>();
-        if (nullptr == buf) {
-            return nullptr;
-        }
-        new (buf) T(a1, a2);
-        return static_cast<T*>(buf);
-    }
-
-    template<typename T, typename A1, typename A2, typename A3>
-    T* createT(const A1& a1, const A2& a2, const A3& a3) {
-        void* buf = this->reserveT<T>();
-        if (nullptr == buf) {
-            return nullptr;
-        }
-        new (buf) T(a1, a2, a3);
-        return static_cast<T*>(buf);
-    }
-
-    template<typename T, typename A1, typename A2, typename A3, typename A4>
-    T* createT(const A1& a1, const A2& a2, const A3& a3, const A4& a4) {
-        void* buf = this->reserveT<T>();
-        if (nullptr == buf) {
-            return nullptr;
-        }
-        new (buf) T(a1, a2, a3, a4);
-        return static_cast<T*>(buf);
+        return new (buf) T(args...);
     }
 
     /*
      *  Reserve a specified amount of space (must be enough space for one T).
      *  The space will be in fStorage if there is room, or on the heap otherwise.
      *  Either way, this class will call ~T() in its destructor and free the heap
      *  allocation if necessary.
      *  Unlike createT(), this method will not call the constructor of T.
      */
     template<typename T> void* reserveT(size_t storageRequired = sizeof(T)) {
@@ skipping 14 matching lines @@
             rec->fHeapStorage = sk_malloc_throw(storageRequired);
             rec->fObj = static_cast<void*>(rec->fHeapStorage);
         } else {
             // There is space in fStorage.
             rec->fStorageSize = storageRequired;
             rec->fHeapStorage = nullptr;
             SkASSERT(SkIsAlign4(fStorageUsed));
             rec->fObj = static_cast<void*>(fStorage + (fStorageUsed / 4));
             fStorageUsed += storageRequired;
         }
-        rec->fKillProc = destroyT<T>;
+        rec->fKillProc = DestroyT<T>;
         fNumObjects++;
         return rec->fObj;
     }
 
     /*
      *  Free the memory reserved last without calling the destructor.
      *  Can be used in a nested way, i.e. after reserving A and B, calling
      *  freeLast once will free B and calling it again will free A.
      */
     void freeLast() {
         SkASSERT(fNumObjects > 0);
         Rec* rec = &fRecs[fNumObjects - 1];
         sk_free(rec->fHeapStorage);
         fStorageUsed -= rec->fStorageSize;
 
         fNumObjects--;
     }
 
 private:
     struct Rec {
         size_t fStorageSize;  // 0 if allocated on heap
         void*  fObj;
         void*  fHeapStorage;
         void   (*fKillProc)(void*);
     };
 
+    // Used to call the destructor for allocated objects.
+    template<typename T>
+    static void DestroyT(void* ptr) {
+        static_cast<T*>(ptr)->~T();
+    }
+
     // Number of bytes used so far.
     size_t              fStorageUsed;
     // Pad the storage size to be 4-byte aligned.
     uint32_t            fStorage[SkAlign4(kTotalBytes) >> 2];
     uint32_t            fNumObjects;
     Rec                 fRecs[kMaxObjects];
 };
 
 #endif // SkSmallAllocator_DEFINED