1 files changed, 172 insertions, 0 deletions
diff --git a/accessible/windows/msaa/nsWinUtils.cpp b/accessible/windows/msaa/nsWinUtils.cpp
new file mode 100644
index 0000000000..14aa023c73
--- /dev/null
+++ b/accessible/windows/msaa/nsWinUtils.cpp
@@ -0,0 +1,172 @@
+/* -*- 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/a11y/DocAccessibleParent.h"
+#include "mozilla/Preferences.h"
+#include "mozilla/StaticPrefs_accessibility.h"
+#include "nsArrayUtils.h"
+#include "nsICSSDeclaration.h"
+#include "mozilla/dom/Document.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<nsICSSDeclaration> 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<Element> domElement(do_QueryInterface(elm));
+  nsCOMPtr<nsICSSDeclaration> cssDecl =
+      window->GetComputedStyle(*domElement, u""_ns, dummy);
+  dummy.SuppressException();
+  return cssDecl.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() || Compatibility::IsVisperoShared()) {
+    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,
+                                    NativeWindowCreateProc* aOnCreateProc) {
+  return ::CreateWindowExW(
+      WS_EX_TRANSPARENT, aWindowClass, L"NetscapeDispatchWnd",
+      WS_CHILD | (aIsActive ? WS_VISIBLE : 0), aX, aY, aWidth, aHeight,
+      aParentWnd, nullptr, GetModuleHandle(nullptr), aOnCreateProc);
+}
+
+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_CREATE: {
+      // Mark this window so that ipc related code can identify it.
+      ::SetPropW(hWnd, kPropNameTabContent, reinterpret_cast<HANDLE>(1));
+
+      auto createStruct = reinterpret_cast<CREATESTRUCT*>(lParam);
+      auto createProc = reinterpret_cast<nsWinUtils::NativeWindowCreateProc*>(
+          createStruct->lpCreateParams);
+
+      if (createProc && *createProc) {
+        (*createProc)(hWnd);
+      }
+
+      return 0;
+    }
+    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) {
+        RefPtr<IAccessible> msaaAccessible;
+        DocAccessible* document =
+            reinterpret_cast<DocAccessible*>(::GetPropW(hWnd, kPropNameDocAcc));
+        if (document) {
+          document->GetNativeInterface(getter_AddRefs(msaaAccessible));
+        } else {
+          DocAccessibleParent* docParent = static_cast<DocAccessibleParent*>(
+              ::GetPropW(hWnd, kPropNameDocAccParent));
+          if (docParent) {
+            if (StaticPrefs::accessibility_cache_enabled_AtStartup()) {
+              msaaAccessible = MsaaAccessible::GetFrom(docParent);
+            } else {
+              docParent->GetCOMInterface(getter_AddRefs(msaaAccessible));
+            }
+          }
+        }
+        if (msaaAccessible) {
+          LRESULT result =
+              ::LresultFromObject(IID_IAccessible, wParam,
+                                  msaaAccessible);  // does an 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);
+}