Implement TransformFeedbackManager in GPU command buffer.

gpu/command_buffer/service/indexed_buffer_binding_host.h

+// Copyright (c) 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef GPU_COMMAND_BUFFER_SERVICE_INDEXED_BUFFER_BINDING_HOST_H_
+#define GPU_COMMAND_BUFFER_SERVICE_INDEXED_BUFFER_BINDING_HOST_H_
+
+#include <vector>
+
+#include "base/memory/ref_counted.h"
+#include "gpu/command_buffer/service/gl_utils.h"
+#include "gpu/gpu_export.h"
+
+namespace gfx {
+struct GLVersionInfo;
+};
+
+namespace gpu {
+namespace gles2 {
+
+class Buffer;
+
+// This is a base class for indexed buffer bindings tracking.
+// TransformFeedback and Program should inherit from this base class,
+// for tracking indexed TRANSFORM_FEEDBACK_BUFFER / UNIFORM_BUFFER bindings.
+class GPU_EXPORT IndexedBufferBindingHost :
+    public base::RefCounted<IndexedBufferBindingHost> {
+ public:
+  IndexedBufferBindingHost(uint32_t max_bindings);
+
+  // The following two functions do state update and call the underlying GL
+  // function.  All validations have been done already and the GL function is
+  // guaranteed to succeed.
+  void DoBindBufferBase(GLenum target, GLuint index, Buffer* buffer);
+  void DoBindBufferRange(
+      const gfx::GLVersionInfo& gl_version_info, GLenum target, GLuint index,
+      Buffer* buffer, GLintptr offset, GLsizeiptr size);
+
+  // This is called on the active host when glBufferData is called and buffer
+  // size might change.
+  void OnBufferData(
+      const gfx::GLVersionInfo& gl_version_info, GLenum target, Buffer* buffer);
+
+  // This is called when the host become active.
+  void OnBindHost(
+      const gfx::GLVersionInfo& gl_version_info, GLenum target);
+
+  void RemoveBoundBuffer(Buffer* buffer);
+
+  Buffer* GetBufferBinding(GLuint index) const;
+  GLsizeiptr GetBufferSize(GLuint index) const;
+  GLintptr GetBufferStart(GLuint index) const;
+
+ protected:
+  friend class base::RefCounted<IndexedBufferBindingHost>;
+
+  virtual ~IndexedBufferBindingHost();
+
+ private:
+  enum IndexedBufferBindingType {
+    kBindBufferBase,
+    kBindBufferRange,
+    kBindBufferNone
+  };
+
+  struct IndexedBufferBinding {
+    IndexedBufferBindingType type;
+    scoped_refptr<Buffer> buffer;
+
+    // The following fields are only used if |type| is kBindBufferRange.
+    GLintptr offset;
+    GLsizeiptr size;
+    // The full buffer size at the last successful glBindBufferRange call.
+    GLsizeiptr effective_full_buffer_size;
+
+    IndexedBufferBinding();
+    IndexedBufferBinding(const IndexedBufferBinding& other);
+    ~IndexedBufferBinding();
+
+    void SetBindBufferBase(Buffer* _buffer);
+    void SetBindBufferRange(
+        Buffer* _buffer, GLintptr _offset, GLsizeiptr _size);
+    void Reset();
+  };
+
+  // This is called on Desktop GL lower than 4.2, where the range
+  // (offset + size) can't go beyond the buffer's size.
+  static void DoAdjustedBindBufferRange(
+      GLenum target, GLuint index, GLuint service_id, GLintptr offset,
+      GLsizeiptr size, GLsizeiptr full_buffer_size);
+
+  std::vector<IndexedBufferBinding> buffer_bindings_;
+};
+
+}  // namespace gles2
+}  // namespace gpu
+
+#endif  // GPU_COMMAND_BUFFER_SERVICE_INDEXED_BUFFER_BINDING_HOST_H_