1 files changed, 181 insertions, 0 deletions
diff --git a/accessible/windows/msaa/nsWinUtils.cpp b/accessible/windows/msaa/nsWinUtils.cpp
new file mode 100644
index 000000000..b49cd0263
--- /dev/null
+++ b/accessible/windows/msaa/nsWinUtils.cpp
@@ -0,0 +1,181 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim:expandtab:shiftwidth=2:tabstop=2:
+ */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "nsWinUtils.h"
+
+#include "Compatibility.h"
+#include "DocAccessible.h"
+#include "nsAccessibilityService.h"
+#include "nsCoreUtils.h"
+
+#include "mozilla/Preferences.h"
+#include "nsArrayUtils.h"
+#include "nsIArray.h"
+#include "nsICSSDeclaration.h"
+#include "nsIDocument.h"
+#include "nsIDocShellTreeItem.h"
+#include "mozilla/dom/Element.h"
+#include "nsXULAppAPI.h"
+
+using namespace mozilla;
+using namespace mozilla::a11y;
+using mozilla::dom::Element;
+
+// Window property used by ipc related code in identifying accessible
+// tab windows.
+const wchar_t* kPropNameTabContent = L"AccessibleTabWindow";
+
+/**
+ * WindowProc to process WM_GETOBJECT messages, used in windows emulation mode.
+ */
+static LRESULT CALLBACK WindowProc(HWND hWnd, UINT msg,
+                                   WPARAM wParam, LPARAM lParam);
+
+bool nsWinUtils::sWindowEmulationStarted = false;
+
+already_AddRefed<nsIDOMCSSStyleDeclaration>
+nsWinUtils::GetComputedStyleDeclaration(nsIContent* aContent)
+{
+  nsIContent* elm = nsCoreUtils::GetDOMElementFor(aContent);
+  if (!elm)
+    return nullptr;
+
+  // Returns number of items in style declaration
+  nsCOMPtr<nsPIDOMWindowInner> window = elm->OwnerDoc()->GetInnerWindow();
+  if (!window)
+    return nullptr;
+
+  ErrorResult dummy;
+  nsCOMPtr<nsICSSDeclaration> cssDecl;
+  nsCOMPtr<Element> domElement(do_QueryInterface(elm));
+  cssDecl = window->GetComputedStyle(*domElement, EmptyString(), dummy);
+  nsCOMPtr<nsIDOMCSSStyleDeclaration> domDecl = do_QueryInterface(cssDecl);
+  dummy.SuppressException();
+  return domDecl.forget();
+}
+
+bool
+nsWinUtils::MaybeStartWindowEmulation()
+{
+  // Register window class that'll be used for document accessibles associated
+  // with tabs.
+  if (IPCAccessibilityActive())
+    return false;
+
+  if (Compatibility::IsJAWS() || Compatibility::IsWE() ||
+      Compatibility::IsDolphin() ||
+      XRE_IsContentProcess()) {
+    RegisterNativeWindow(kClassNameTabContent);
+    sWindowEmulationStarted = true;
+    return true;
+  }
+
+  return false;
+}
+
+void
+nsWinUtils::ShutdownWindowEmulation()
+{
+  // Unregister window call that's used for document accessibles associated
+  // with tabs.
+  if (IsWindowEmulationStarted()) {
+    ::UnregisterClassW(kClassNameTabContent, GetModuleHandle(nullptr));
+    sWindowEmulationStarted = false;
+  }
+}
+
+void
+nsWinUtils::RegisterNativeWindow(LPCWSTR aWindowClass)
+{
+  WNDCLASSW wc;
+  wc.style = CS_GLOBALCLASS;
+  wc.lpfnWndProc = WindowProc;
+  wc.cbClsExtra = 0;
+  wc.cbWndExtra = 0;
+  wc.hInstance = GetModuleHandle(nullptr);
+  wc.hIcon = nullptr;
+  wc.hCursor = nullptr;
+  wc.hbrBackground = nullptr;
+  wc.lpszMenuName = nullptr;
+  wc.lpszClassName = aWindowClass;
+  ::RegisterClassW(&wc);
+}
+
+HWND
+nsWinUtils::CreateNativeWindow(LPCWSTR aWindowClass, HWND aParentWnd,
+                               int aX, int aY, int aWidth, int aHeight,
+                               bool aIsActive)
+{
+  HWND hwnd = ::CreateWindowExW(WS_EX_TRANSPARENT, aWindowClass,
+                                L"NetscapeDispatchWnd",
+                                WS_CHILD | (aIsActive ? WS_VISIBLE : 0),
+                                aX, aY, aWidth, aHeight,
+                                aParentWnd,
+                                nullptr,
+                                GetModuleHandle(nullptr),
+                                nullptr);
+  if (hwnd) {
+    // Mark this window so that ipc related code can identify it.
+    ::SetPropW(hwnd, kPropNameTabContent, (HANDLE)1);
+  }
+  return hwnd;
+}
+
+void
+nsWinUtils::ShowNativeWindow(HWND aWnd)
+{
+  ::ShowWindow(aWnd, SW_SHOW);
+}
+
+void
+nsWinUtils::HideNativeWindow(HWND aWnd)
+{
+  ::SetWindowPos(aWnd, nullptr, 0, 0, 0, 0,
+                 SWP_HIDEWINDOW | SWP_NOSIZE | SWP_NOMOVE |
+                 SWP_NOZORDER | SWP_NOACTIVATE);
+}
+
+LRESULT CALLBACK
+WindowProc(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam)
+{
+  // Note, this window's message handling should not invoke any call that
+  // may result in a cross-process ipc call. Doing so may violate RPC
+  // message semantics.
+
+  switch (msg) {
+    case WM_GETOBJECT:
+    {
+      // Do explicit casting to make it working on 64bit systems (see bug 649236
+      // for details).
+      int32_t objId = static_cast<DWORD>(lParam);
+      if (objId == OBJID_CLIENT) {
+        DocAccessible* document =
+          reinterpret_cast<DocAccessible*>(::GetPropW(hWnd, kPropNameDocAcc));
+        if (document) {
+          IAccessible* msaaAccessible = nullptr;
+          document->GetNativeInterface((void**)&msaaAccessible); // does an addref
+          if (msaaAccessible) {
+            LRESULT result = ::LresultFromObject(IID_IAccessible, wParam,
+                                                 msaaAccessible); // does an addref
+            msaaAccessible->Release(); // release extra addref
+            return result;
+          }
+        }
+      }
+      return 0;
+    }
+    case WM_NCHITTEST:
+    {
+      LRESULT lRet = ::DefWindowProc(hWnd, msg, wParam, lParam);
+      if (HTCLIENT == lRet)
+        lRet = HTTRANSPARENT;
+      return lRet;
+    }
+  }
+
+  return ::DefWindowProcW(hWnd, msg, wParam, lParam);
+}