Plumbing explicit share groups through context creation

content/common/gpu/client/webgraphicscontext3d_command_buffer_impl.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 CONTENT_COMMON_GPU_CLIENT_WEBGRAPHICSCONTEXT3D_COMMAND_BUFFER_IMPL_H_
 #define CONTENT_COMMON_GPU_CLIENT_WEBGRAPHICSCONTEXT3D_COMMAND_BUFFER_IMPL_H_
 
 #include <string>
 #include <vector>
 
 #include "base/callback.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
+#include "base/synchronization/lock.h"
 #include "content/common/content_export.h"
 #include "content/common/gpu/client/command_buffer_proxy_impl.h"
 #include "third_party/WebKit/public/platform/WebGraphicsContext3D.h"
 #include "third_party/WebKit/public/platform/WebString.h"
 #include "ui/gfx/native_widget_types.h"
 #include "ui/gl/gpu_preference.h"
 #include "url/gurl.h"
 
 namespace gpu {
 
@@ skipping 42 matching lines @@
   struct CONTENT_EXPORT SharedMemoryLimits {
     SharedMemoryLimits();
 
     size_t command_buffer_size;
     size_t start_transfer_buffer_size;
     size_t min_transfer_buffer_size;
     size_t max_transfer_buffer_size;
     size_t mapped_memory_reclaim_limit;
   };
 
+  class ShareGroup : public base::RefCountedThreadSafe<ShareGroup> {
+   public:
+    ShareGroup();
+
+    WebGraphicsContext3DCommandBufferImpl* GetAnyContextLocked() {
+      // In order to ensure that the context returned is not removed while
+      // in use the share group's lock should be aquired before calling this
+      // function.
+      lock_.AssertAcquired();
+      if (contexts_.empty())
+        return NULL;
+      return contexts_.front();
+    }
+
+    void AddContextLocked(WebGraphicsContext3DCommandBufferImpl* context) {
+      lock_.AssertAcquired();
+      contexts_.push_back(context);
+    }
+
+    void RemoveContext(WebGraphicsContext3DCommandBufferImpl* context) {
+      base::AutoLock auto_lock(lock_);
+      contexts_.erase(std::remove(contexts_.begin(), contexts_.end(), context),
+          contexts_.end());
+    }
+
+    void RemoveAllContexts() {
+      base::AutoLock auto_lock(lock_);
+      contexts_.clear();
+    }
+
+    base::Lock& lock() {
+      return lock_;
+    }
+
+   private:
+    friend class base::RefCountedThreadSafe<ShareGroup>;
+    ~ShareGroup();
+
+    std::vector<WebGraphicsContext3DCommandBufferImpl*> contexts_;
+    base::Lock lock_;
+
+    DISALLOW_COPY_AND_ASSIGN(ShareGroup);
+  };
+
   WebGraphicsContext3DCommandBufferImpl(
       int surface_id,
       const GURL& active_url,
       GpuChannelHost* host,
       const Attributes& attributes,
       bool bind_generates_resources,
-      const SharedMemoryLimits& limits);
+      const SharedMemoryLimits& limits,
+      WebGraphicsContext3DCommandBufferImpl* share_context);
 
   virtual ~WebGraphicsContext3DCommandBufferImpl();
 
   // The following 3 IDs let one uniquely identify this context.
   // Gets the GPU process ID for this context.
   int GetGPUProcessID();
 
   CommandBufferProxyImpl* GetCommandBufferProxy() {
     return command_buffer_.get();
   }
 
   CONTENT_EXPORT gpu::ContextSupport* GetContextSupport();
 
   gpu::gles2::GLES2Implementation* GetImplementation() {
     return real_gl_.get();
   }
 
   // Return true if GPU process reported context lost or there was a
   // problem communicating with the GPU process.
   bool IsCommandBufferContextLost();
 
   // Create & initialize a WebGraphicsContext3DCommandBufferImpl.  Return NULL
   // on any failure.
   static CONTENT_EXPORT WebGraphicsContext3DCommandBufferImpl*
       CreateOffscreenContext(
           GpuChannelHost* host,
           const WebGraphicsContext3D::Attributes& attributes,
           const GURL& active_url,
-          const SharedMemoryLimits& limits);
+          const SharedMemoryLimits& limits,
+          WebGraphicsContext3DCommandBufferImpl* share_context);
 
   size_t GetMappedMemoryLimit() {
     return mem_limits_.mapped_memory_reclaim_limit;
   }
 
   //----------------------------------------------------------------------
   // WebGraphicsContext3D methods
 
   // Must be called after initialize() and before any of the following methods.
   // Permanently binds to the first calling thread. Returns false if the
@@ skipping 543 matching lines @@
     FAIL_IF_MAJOR_PERF_CAVEAT = 0x10002
   };
   friend class WebGraphicsContext3DErrorMessageCallback;
 
   // Initialize the underlying GL context. May be called multiple times; second
   // and subsequent calls are ignored. Must be called from the thread that is
   // going to use this object to issue GL commands (which might not be the main
   // thread).
   bool MaybeInitializeGL();
 
-  bool InitializeCommandBuffer(bool onscreen);
+  bool InitializeCommandBuffer(bool onscreen,
+      WebGraphicsContext3DCommandBufferImpl* share_context);
 
   void Destroy();
 
   // Create a CommandBufferProxy that renders directly to a view. The view and
   // the associated window must not be destroyed until the returned
   // CommandBufferProxy has been destroyed, otherwise the GPU process might
   // attempt to render to an invalid window handle.
   //
   // NOTE: on Mac OS X, this entry point is only used to set up the
   // accelerated compositor's output. On this platform, we actually pass
@@ skipping 38 matching lines @@
   scoped_ptr<gpu::gles2::GLES2CmdHelper> gles2_helper_;
   scoped_ptr<gpu::TransferBuffer> transfer_buffer_;
   gpu::gles2::GLES2Interface* gl_;
   scoped_ptr<gpu::gles2::GLES2Implementation> real_gl_;
   scoped_ptr<gpu::gles2::GLES2Interface> trace_gl_;
   Error last_error_;
   bool bind_generates_resources_;
   SharedMemoryLimits mem_limits_;
 
   uint32_t flush_id_;
+  scoped_refptr<ShareGroup> share_group_;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_COMMON_GPU_CLIENT_WEBGRAPHICSCONTEXT3D_COMMAND_BUFFER_IMPL_H_