1 files changed, 78 insertions, 0 deletions
diff --git a/chrome/plugin/command_buffer_stub_win.cc b/chrome/plugin/command_buffer_stub_win.cc
new file mode 100644
index 0000000..656bbd1
--- /dev/null
+++ b/chrome/plugin/command_buffer_stub_win.cc
@@ -0,0 +1,78 @@
+// Copyright (c) 2010 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.
+
+#include <windows.h>
+
+#include "chrome/common/command_buffer_messages.h"
+#include "chrome/plugin/command_buffer_stub.h"
+
+namespace {
+const wchar_t* kPreviousWndProcProperty = L"CommandBufferStubPrevWndProc";
+const wchar_t* kCommandBufferStubProperty = L"CommandBufferStub";
+
+// Message handler for the GPU plugin's child window. Used to intercept
+// WM_PAINT events and forward repaint notifications to the client.
+LRESULT WINAPI WndProc(HWND handle,
+                       UINT message,
+                       WPARAM w_param,
+                       LPARAM l_param) {
+  WNDPROC previous_wnd_proc = reinterpret_cast<WNDPROC>(
+      ::GetProp(handle, kPreviousWndProcProperty));
+  CommandBufferStub* stub = reinterpret_cast<CommandBufferStub*>(
+      ::GetProp(handle, kCommandBufferStubProperty));
+
+  switch (message) {
+    case WM_ERASEBKGND:
+      // Do not clear background. Avoids flickering.
+      return 1;
+    case WM_PAINT:
+      // Validate the whole window to prevent another WM_PAINT message.
+      ValidateRect(handle, NULL);
+
+      // Notify client that the window is invalid and needs to be repainted.
+      stub->NotifyRepaint();
+
+      return 1;
+    default:
+      return CallWindowProc(previous_wnd_proc,
+                            handle,
+                            message,
+                            w_param,
+                            l_param);
+  }
+}
+}  // namespace anonymous
+
+void CommandBufferStub::NotifyRepaint() {
+  Send(new CommandBufferMsg_NotifyRepaint(route_id_));
+}
+
+bool CommandBufferStub::InitializePlatformSpecific() {
+  // Subclass window.
+  WNDPROC previous_wnd_proc = reinterpret_cast<WNDPROC>(
+      ::GetWindowLongPtr(window_, GWLP_WNDPROC));
+  ::SetProp(window_,
+            kPreviousWndProcProperty,
+            reinterpret_cast<HANDLE>(previous_wnd_proc));
+  ::SetWindowLongPtr(window_,
+                     GWLP_WNDPROC,
+                     reinterpret_cast<LONG_PTR>(WndProc));
+
+  // Record pointer to this in window.
+  ::SetProp(window_,
+            kCommandBufferStubProperty,
+            reinterpret_cast<HANDLE>(this));
+
+  return true;
+}
+
+void CommandBufferStub::DestroyPlatformSpecific() {
+  // Restore window.
+  WNDPROC previous_wnd_proc = reinterpret_cast<WNDPROC>(
+      ::GetProp(window_, kPreviousWndProcProperty));
+  ::SetWindowLongPtr(window_, GWLP_WNDPROC, reinterpret_cast<LONG_PTR>(
+      previous_wnd_proc));
+  ::RemoveProp(window_, kPreviousWndProcProperty);
+  ::RemoveProp(window_, kCommandBufferStubProperty);
+}