The Tor Browser / file revision

 /* -*- 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 "nsCoreUtils.h"

 #include "mozilla/Preferences.h"

 #include "nsArrayUtils.h"

 #include "nsIArray.h"

 #include "nsIDocument.h"

 #include "nsIDocShellTreeItem.h"

 #include "nsXULAppAPI.h"

 using namespace mozilla;

 using namespace mozilla::a11y;

 // 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);

 nsRefPtrHashtable<nsPtrHashKey<void>, DocAccessible>* nsWinUtils::sHWNDCache = nullptr;

 already_AddRefed<nsIDOMCSSStyleDeclaration>

 nsWinUtils::GetComputedStyleDeclaration(nsIContent* aContent)

 {

   nsIContent* elm = nsCoreUtils::GetDOMElementFor(aContent);

   if (!elm)

     return nullptr;

   // Returns number of items in style declaration

   nsCOMPtr<nsIDOMWindow> window =

     do_QueryInterface(elm->OwnerDoc()->GetWindow());

   if (!window)

     return nullptr;

   nsCOMPtr<nsIDOMCSSStyleDeclaration> cssDecl;

   nsCOMPtr<nsIDOMElement> domElement(do_QueryInterface(elm));

   window->GetComputedStyle(domElement, EmptyString(), getter_AddRefs(cssDecl));

   return cssDecl.forget();

 }

 bool

 nsWinUtils::MaybeStartWindowEmulation()

 {

   // Register window class that'll be used for document accessibles associated

   // with tabs.

   if (Compatibility::IsJAWS() || Compatibility::IsWE() ||

       Compatibility::IsDolphin() ||

       XRE_GetProcessType() == GeckoProcessType_Content) {

     RegisterNativeWindow(kClassNameTabContent);

     sHWNDCache = new nsRefPtrHashtable<nsPtrHashKey<void>, DocAccessible>(4);

     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));

 }

 bool

 nsWinUtils::IsWindowEmulationStarted()

 {

   return sHWNDCache != nullptr;

 }

 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:

     {

       if (lParam == OBJID_CLIENT) {

         DocAccessible* document =

           nsWinUtils::sHWNDCache->GetWeak(static_cast<void*>(hWnd));

         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);

 }