Implemented support for GL constext share groups in the renderer process.

gpu/command_buffer/common/id_allocator.h

 // Copyright (c) 2011 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.
 
 // This file contains the definition of the IdAllocator class.
 
 #ifndef GPU_COMMAND_BUFFER_CLIENT_ID_ALLOCATOR_H_
 #define GPU_COMMAND_BUFFER_CLIENT_ID_ALLOCATOR_H_
 
 #include <set>
 #include <utility>
 #include "../common/types.h"
 
+// TODO(apatrick): Having regular GL flush semantics on the client side, it
+// probably isn't necessary to round trip to the service to allocate IDs.
+// Retire this code.
+
 namespace gpu {
 
 // A resource ID, key to the resource maps.
 typedef uint32 ResourceId;
 // Invalid resource ID.
 static const ResourceId kInvalidResource = 0u;
 
-// A class to manage the allocation of resource IDs.
-class IdAllocator {
+class IdAllocatorInterface {
  public:
-  IdAllocator();
-  ~IdAllocator();
+  virtual ~IdAllocatorInterface();
 
   // Allocates a new resource ID.
-  ResourceId AllocateID();
+  virtual ResourceId AllocateID() = 0;
 
   // Allocates an Id starting at or above desired_id.
   // Note: may wrap if it starts near limit.
-  ResourceId AllocateIDAtOrAbove(ResourceId desired_id);
+  virtual ResourceId AllocateIDAtOrAbove(ResourceId desired_id) = 0;
 
   // Marks an id as used. Returns false if id was already used.
-  bool MarkAsUsed(ResourceId id);
+  virtual bool MarkAsUsed(ResourceId id) = 0;
 
   // Frees a resource ID.
-  void FreeID(ResourceId id);
+  virtual void FreeID(ResourceId id) = 0;
 
   // Checks whether or not a resource ID is in use.
-  bool InUse(ResourceId id) const;
+  virtual bool InUse(ResourceId id) const = 0;
+};
+
+// A class to manage the allocation of resource IDs.
+class IdAllocator : public IdAllocatorInterface {
+ public:
+  IdAllocator();
+  virtual ~IdAllocator();
+
+  // Implement IdAllocatorInterface.
+  virtual ResourceId AllocateID();
+  virtual ResourceId AllocateIDAtOrAbove(ResourceId desired_id);
+  virtual bool MarkAsUsed(ResourceId id);
+  virtual void FreeID(ResourceId id);
+  virtual bool InUse(ResourceId id) const;
 
  private:
   // TODO(gman): This would work much better with ranges or a hash table.
   typedef std::set<ResourceId> ResourceIdSet;
 
   // The highest ID on the used list.
   ResourceId LastUsedId() const;
 
   // Lowest ID that isn't on the used list. This is slow, use as a last resort.
   ResourceId FindFirstUnusedId() const;
 
   ResourceIdSet used_ids_;
   ResourceIdSet free_ids_;
 
   DISALLOW_COPY_AND_ASSIGN(IdAllocator);
 };
 
+// A class to manage the allocation of resource IDs that are never reused. This
+// implementation does not track which IDs are currently used. It is usedul for

[jamesr, 2011/08/03 21:51:20]

typo: usedul -> useful

+// shared and programs which cannot be implicitly created by binding a
+// previously unused ID.
+class NonReusedIdAllocator : public IdAllocatorInterface {
+ public:
+  NonReusedIdAllocator();
+  virtual ~NonReusedIdAllocator();
+
+  // Implement IdAllocatorInterface.
+  virtual ResourceId AllocateID();
+  virtual ResourceId AllocateIDAtOrAbove(ResourceId desired_id);
+  virtual bool MarkAsUsed(ResourceId id);
+  virtual void FreeID(ResourceId id);
+  virtual bool InUse(ResourceId id) const;
+
+ private:
+  ResourceId last_id_;
+
+  DISALLOW_COPY_AND_ASSIGN(NonReusedIdAllocator);
+};
+
 }  // namespace gpu
 
 #endif  // GPU_COMMAND_BUFFER_CLIENT_ID_ALLOCATOR_H_