Allow textures to be moved from one GL context group to another.

gpu/command_buffer/service/mailbox_manager.h

+// Copyright (c) 2012 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_DISPLAY_H_
+#define GPU_COMMAND_BUFFER_SERVICE_DISPLAY_H_
+
+#include <queue>
+
+#include "base/hash_tables.h"
+#include "base/memory/linked_ptr.h"
+#include "base/memory/ref_counted.h"
+#include "gpu/command_buffer/common/constants.h"
+#include "gpu/gpu_export.h"
+
+namespace gpu {
+namespace gles2 {
+
+class TextureDefinition;
+class TextureManager;
+
+// Identified a mailbox where a texture definition can be stored for sharing

[greggman, 2012/04/26 18:09:18]

s/Identified/Identifies/ ?

+// transferring between contexts that are not in the same context group. It is
+// generally a large random number.
+struct MailboxName {
+  char components[kMailboxSize];
+};
+
+// Manages resources scoped beyond the context or context group level.
+class GPU_EXPORT MailboxManager : public base::RefCounted<MailboxManager> {
+ public:
+  MailboxManager();
+
+  // Remove the texture definition from the named mailbox and empty the mailbox.
+  TextureDefinition* ConsumeTexture(unsigned target, const MailboxName& name);
+
+  // Put the texture definition in the named mailbox.
+  void ProduceTexture(unsigned target,
+                      const MailboxName& name,
+                      TextureDefinition* definition,
+                      TextureManager* owner);
+
+  // Destroy any texture definitions and mailboxes owned by the given texture
+  // manager.
+  void DestroyOwnedTextures(TextureManager* owner, bool have_context);
+
+ private:
+  friend class base::RefCounted<MailboxManager>;
+
+  struct TargetName {
+    TargetName(unsigned target, const MailboxName& name);
+    unsigned target;
+    MailboxName name;
+  };
+
+  struct TargetNameCompare {
+    enum {
+      bucket_size = 4,
+      min_buckets = 8
+    };
+    size_t operator() (const TargetName& key) const;
+    int operator() (const TargetName& lhs, const TargetName& rhs) const;
+  };
+
+  struct OwnedTextureDefinition {
+    OwnedTextureDefinition(TextureDefinition* definition,
+                           TextureManager* owner);
+    linked_ptr<TextureDefinition> definition;
+    TextureManager* owner;
+  };
+
+  typedef base::hash_map<TargetName, OwnedTextureDefinition, TargetNameCompare>
+      TextureDefinitionMap;
+
+  ~MailboxManager();
+
+  TextureDefinitionMap textures_;
+
+  DISALLOW_COPY_AND_ASSIGN(MailboxManager);
+};
+}  // namespage gles2
+}  // namespace gpu
+
+#endif  // GPU_COMMAND_BUFFER_SERVICE_DISPLAY_H_
+
+