gpu/command_buffer/common/mailbox.h

   1 // Copyright 2013 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef GPU_COMMAND_BUFFER_MAILBOX_H_
   6 #define GPU_COMMAND_BUFFER_MAILBOX_H_
   7
   8 #include <stdint.h>
   9 #include <string.h>
  10
  11 #include "gpu/gpu_export.h"
  12
  13 // From gl2/gl2ext.h.
  14 #ifndef GL_MAILBOX_SIZE_CHROMIUM
  15 #define GL_MAILBOX_SIZE_CHROMIUM 64
  16 #endif
  17
  18 namespace gpu {
  19
  20 // A mailbox is an unguessable name that references texture image data.
  21 // This name can be passed across processes permitting one context to share
  22 // texture image data with another. The mailbox name consists of a random
  23 // set of bytes, optionally with a checksum (in debug mode) to verify the
  24 // name is valid.
  25 // See src/gpu/GLES2/extensions/CHROMIUM/CHROMIUM_texture_mailbox.txt for more
  26 // details.
  27 struct GPU_EXPORT Mailbox {
  28   using Name = int8_t[GL_MAILBOX_SIZE_CHROMIUM];
  29
  30   Mailbox();
  31   bool IsZero() const;
  32   void SetZero();
  33   void SetName(const int8_t* name);
  34
  35   // Generate a unique unguessable mailbox name.
  36   static Mailbox Generate();
  37
  38   // Verify that the mailbox was created through Mailbox::Generate. This only
  39   // works in Debug (always returns true in Release). This is not a secure
  40   // check, only to catch bugs where clients forgot to call Mailbox::Generate.
  41   bool Verify() const;
  42
  43   Name name;
  44
  45   bool operator<(const Mailbox& other) const {
  46     return memcmp(this, &other, sizeof other) < 0;
  47   }
  48   bool operator==(const Mailbox& other) const {
  49     return memcmp(this, &other, sizeof other) == 0;
  50   }
  51   bool operator!=(const Mailbox& other) const {
  52     return !operator==(other);
  53   }
  54 };
  55
  56 }  // namespace gpu
  57
  58 #endif  // GPU_COMMAND_BUFFER_MAILBOX_H_
  59