add gpu backend (not hooked up yet)



git-svn-id: http://skia.googlecode.com/svn/trunk@649 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/gpu/include/GrIndexBuffer.h b/gpu/include/GrIndexBuffer.h
new file mode 100644
index 0000000..0f4c4d6
--- /dev/null
+++ b/gpu/include/GrIndexBuffer.h
@@ -0,0 +1,92 @@
+/*
+    Copyright 2010 Google Inc.
+
+    Licensed under the Apache License, Version 2.0 (the "License");
+    you may not use this file except in compliance with the License.
+    You may obtain a copy of the License at
+
+         http://www.apache.org/licenses/LICENSE-2.0
+
+    Unless required by applicable law or agreed to in writing, software
+    distributed under the License is distributed on an "AS IS" BASIS,
+    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+    See the License for the specific language governing permissions and
+    limitations under the License.
+ */
+
+
+#ifndef GrIndexBuffer_DEFINED
+#define GrIndexBuffer_DEFINED
+
+#include "GrRefCnt.h"
+
+class GrIndexBuffer : public GrRefCnt {
+protected:
+    GrIndexBuffer(uint32_t sizeInBytes, bool dynamic) : 
+                  fSizeInBytes(sizeInBytes),
+                  fDynamic(dynamic) {}
+public:
+    virtual ~GrIndexBuffer() {}
+    
+    /**
+     Retrieves the size of the index buffer
+
+     @return the size of the index buffer in bytes
+     */
+    uint32_t size() const { return fSizeInBytes; }
+   
+    /**
+     Retrieves whether the index buffer was created with the dynamic flag
+
+     @return true if the index buffer was created with the dynamic flag
+     */
+    bool dynamic() const { return fDynamic; }
+
+    /**
+     Indicates that GPU context in which this veretx buffer was created is 
+     destroyed and that Ganesh should not attempt to free the texture with the
+     underlying API.
+     */
+    virtual void abandon() = 0;
+
+    /**
+     Locks the index buffer to be written by the CPU.
+     
+     The previous content of the index buffer is invalidated. It is an error to
+     draw whil the buffer is locked.  It is an error to call lock on an already
+     locked index buffer.
+     
+     @return a pointer to the index data or NULL if the lock fails.
+     */
+    virtual void* lock() = 0;
+
+    /** 
+     Unlocks the index buffer. 
+     
+     The pointer returned by the previous lock call will no longer be valid.
+     */
+    virtual void unlock() = 0;
+
+    /** 
+     Queries whether the index buffer has been locked.
+     
+     @return true if the index buffer is locked, false otherwise.
+     */
+    virtual bool isLocked() const = 0;
+
+    /**
+     Updates the index buffer data. 
+     
+     The size of the index buffer will be preserved. However, only the updated 
+     region will have defined contents.
+
+     @return returns true if the update succeeds, false otherwise.
+     */
+    virtual bool updateData(const void* src, uint32_t srcSizeInBytes) = 0;
+
+private:
+    uint32_t fSizeInBytes;
+    bool     fDynamic;
+};
+
+#endif