content/canvas/src/WebGLElementArrayCache.h

   1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
   2 /* This Source Code Form is subject to the terms of the Mozilla Public
   3  * License, v. 2.0. If a copy of the MPL was not distributed with this
   4  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   5
   6 #ifndef WEBGLELEMENTARRAYCACHE_H
   7 #define WEBGLELEMENTARRAYCACHE_H
   8
   9 #include "mozilla/MemoryReporting.h"
  10 #include <stdint.h>
  11 #include "nscore.h"
  12 #include "GLDefs.h"
  13
  14 namespace mozilla {
  15
  16 template<typename T>
  17 struct WebGLElementArrayCacheTree;
  18
  19 /*
  20  * WebGLElementArrayCache implements WebGL element array buffer validation for drawElements.
  21  *
  22  * Its exposes methods meant to be called by WebGL method implementations:
  23  *  - Validate, to be called by WebGLContext::DrawElements, is where we use the cache
  24  *  - BufferData and BufferSubData, to be called by eponymous WebGL methods, are how
  25  *    data is fed into the cache
  26  *
  27  * Most of the implementation is hidden in the auxilary class template, WebGLElementArrayCacheTree.
  28  * Refer to its code for design comments.
  29  */
  30 class WebGLElementArrayCache {
  31
  32 public:
  33   bool BufferData(const void* ptr, size_t byteSize);
  34   void BufferSubData(size_t pos, const void* ptr, size_t updateByteSize);
  35
  36   bool Validate(GLenum type, uint32_t maxAllowed, size_t first, size_t count);
  37
  38   template<typename T>
  39   T Element(size_t i) const { return Elements<T>()[i]; }
  40
  41   WebGLElementArrayCache()
  42     : mUntypedData(nullptr)
  43     , mByteSize(0)
  44     , mUint8Tree(nullptr)
  45     , mUint16Tree(nullptr)
  46     , mUint32Tree(nullptr)
  47   {}
  48
  49   ~WebGLElementArrayCache();
  50
  51   size_t SizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf) const;
  52
  53 private:
  54
  55   template<typename T>
  56   bool Validate(uint32_t maxAllowed, size_t first, size_t count);
  57
  58   size_t ByteSize() const {
  59     return mByteSize;
  60   }
  61
  62   template<typename T>
  63   const T* Elements() const { return static_cast<const T*>(mUntypedData); }
  64   template<typename T>
  65   T* Elements() { return static_cast<T*>(mUntypedData); }
  66
  67   void InvalidateTrees(size_t firstByte, size_t lastByte);
  68
  69   template<typename T>
  70   friend struct WebGLElementArrayCacheTree;
  71   template<typename T>
  72   friend struct TreeForType;
  73
  74   void* mUntypedData;
  75   size_t mByteSize;
  76   WebGLElementArrayCacheTree<uint8_t>* mUint8Tree;
  77   WebGLElementArrayCacheTree<uint16_t>* mUint16Tree;
  78   WebGLElementArrayCacheTree<uint32_t>* mUint32Tree;
  79 };
  80
  81
  82 } // end namespace mozilla
  83
  84 #endif // WEBGLELEMENTARRAYCACHE_H