The Tor Browser: accessible/src/windows/msaa/AccessibleWrap.cpp@6474c204b198 (annotated)

accessible/src/windows/msaa/AccessibleWrap.cpp@6474c204b198 (annotated)

accessible/src/windows/msaa/AccessibleWrap.cpp

Wed, 31 Dec 2014 06:09:35 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Wed, 31 Dec 2014 06:09:35 +0100
changeset 0: 6474c204b198
permissions: -rw-r--r--

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
 /* vim: set ts=2 et sw=2 tw=80: */
 /* 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 "AccessibleWrap.h"
 #include "Accessible-inl.h"
 #include "Compatibility.h"
 #include "DocAccessible-inl.h"
 #include "EnumVariant.h"
 #include "nsAccUtils.h"
 #include "nsCoreUtils.h"
 #include "nsIAccessibleEvent.h"
 #include "nsIAccessibleRelation.h"
 #include "nsWinUtils.h"
 #include "ServiceProvider.h"
 #include "Relation.h"
 #include "Role.h"
 #include "RootAccessible.h"
 #include "sdnAccessible.h"
 #include "States.h"
 #ifdef A11Y_LOG
 #include "Logging.h"
 #endif
 #include "nsIMutableArray.h"
 #include "nsIFrame.h"
 #include "nsIScrollableFrame.h"
 #include "nsINodeInfo.h"
 #include "nsIServiceManager.h"
 #include "nsNameSpaceManager.h"
 #include "nsTextFormatter.h"
 #include "nsView.h"
 #include "nsViewManager.h"
 #include "nsEventMap.h"
 #include "nsArrayUtils.h"
 #include "mozilla/Preferences.h"
 #include "oleacc.h"
 using namespace mozilla;
 using namespace mozilla::a11y;
 const uint32_t USE_ROLE_STRING = 0;
 /* For documentation of the accessibility architecture,
  * see http://lxr.mozilla.org/seamonkey/source/accessible/accessible-docs.html
  */
 //#define DEBUG_LEAKS
 #ifdef DEBUG_LEAKS
 static gAccessibles = 0;
 #endif
 static const int32_t kIEnumVariantDisconnected = -1;
 ////////////////////////////////////////////////////////////////////////////////
 // AccessibleWrap
 ////////////////////////////////////////////////////////////////////////////////
 ITypeInfo* AccessibleWrap::gTypeInfo = nullptr;
 NS_IMPL_ISUPPORTS_INHERITED0(AccessibleWrap, Accessible)
 //-----------------------------------------------------
 // IUnknown interface methods - see iunknown.h for documentation
 //-----------------------------------------------------
 // Microsoft COM QueryInterface
 STDMETHODIMP
 AccessibleWrap::QueryInterface(REFIID iid, void** ppv)
 {
   A11Y_TRYBLOCK_BEGIN
   if (!ppv)
     return E_INVALIDARG;
   *ppv = nullptr;
   if (IID_IUnknown == iid || IID_IDispatch == iid || IID_IAccessible == iid)
     *ppv = static_cast<IAccessible*>(this);
   else if (IID_IEnumVARIANT == iid) {
     // Don't support this interface for leaf elements.
     if (!HasChildren() || nsAccUtils::MustPrune(this))
       return E_NOINTERFACE;
     *ppv = static_cast<IEnumVARIANT*>(new ChildrenEnumVariant(this));
   } else if (IID_IServiceProvider == iid)
     *ppv = new ServiceProvider(this);
   else if (IID_ISimpleDOMNode == iid) {
     if (IsDefunct() || (!HasOwnContent() && !IsDoc()))
       return E_NOINTERFACE;
     *ppv = static_cast<ISimpleDOMNode*>(new sdnAccessible(GetNode()));
   }
   if (nullptr == *ppv) {
     HRESULT hr = ia2Accessible::QueryInterface(iid, ppv);
     if (SUCCEEDED(hr))
       return hr;
   }
   if (nullptr == *ppv) {
     HRESULT hr = ia2AccessibleComponent::QueryInterface(iid, ppv);
     if (SUCCEEDED(hr))
       return hr;
   }
   if (nullptr == *ppv) {
     HRESULT hr = ia2AccessibleHyperlink::QueryInterface(iid, ppv);
     if (SUCCEEDED(hr))
       return hr;
   }
   if (nullptr == *ppv) {
     HRESULT hr = ia2AccessibleValue::QueryInterface(iid, ppv);
     if (SUCCEEDED(hr))
       return hr;
   }
   if (nullptr == *ppv)
     return E_NOINTERFACE;
   (reinterpret_cast<IUnknown*>(*ppv))->AddRef();
   return S_OK;
   A11Y_TRYBLOCK_END
 }
 //-----------------------------------------------------
 // IAccessible methods
 //-----------------------------------------------------
 STDMETHODIMP
 AccessibleWrap::get_accParent( IDispatch __RPC_FAR *__RPC_FAR *ppdispParent)
 {
   A11Y_TRYBLOCK_BEGIN
   if (!ppdispParent)
     return E_INVALIDARG;
   *ppdispParent = nullptr;
   if (IsDefunct())
     return CO_E_OBJNOTCONNECTED;
   DocAccessible* doc = AsDoc();
   if (doc) {
     // Return window system accessible object for root document and tab document
     // accessibles.
     if (!doc->ParentDocument() ||
         (nsWinUtils::IsWindowEmulationStarted() &&
          nsCoreUtils::IsTabDocument(doc->DocumentNode()))) {
       HWND hwnd = static_cast<HWND>(doc->GetNativeWindow());
       if (hwnd && SUCCEEDED(::AccessibleObjectFromWindow(hwnd, OBJID_WINDOW,
                                                          IID_IAccessible,
                                                          (void**)ppdispParent))) {
         return S_OK;
       }
     }
   }
   Accessible* xpParentAcc = Parent();
   if (!xpParentAcc)
     return S_FALSE;
   *ppdispParent = NativeAccessible(xpParentAcc);
   return S_OK;
   A11Y_TRYBLOCK_END
 }
 STDMETHODIMP
 AccessibleWrap::get_accChildCount( long __RPC_FAR *pcountChildren)
 {
   A11Y_TRYBLOCK_BEGIN
   if (!pcountChildren)
     return E_INVALIDARG;
   *pcountChildren = 0;
   if (IsDefunct())
     return CO_E_OBJNOTCONNECTED;
   if (nsAccUtils::MustPrune(this))
     return S_OK;
   *pcountChildren = ChildCount();
   return S_OK;
   A11Y_TRYBLOCK_END
 }
 STDMETHODIMP
 AccessibleWrap::get_accChild(
       /* [in] */ VARIANT varChild,
       /* [retval][out] */ IDispatch __RPC_FAR *__RPC_FAR *ppdispChild)
 {
   A11Y_TRYBLOCK_BEGIN
   if (!ppdispChild)
     return E_INVALIDARG;
   *ppdispChild = nullptr;
   if (IsDefunct())
     return CO_E_OBJNOTCONNECTED;
   // IAccessible::accChild is used to return this accessible or child accessible
   // at the given index or to get an accessible by child ID in the case of
   // document accessible (it's handled by overriden GetXPAccessibleFor method
   // on the document accessible). The getting an accessible by child ID is used
   // by AccessibleObjectFromEvent() called by AT when AT handles our MSAA event.
   Accessible* child = GetXPAccessibleFor(varChild);
   if (!child)
     return E_INVALIDARG;
   if (child->IsDefunct())
     return CO_E_OBJNOTCONNECTED;
   *ppdispChild = NativeAccessible(child);
   return S_OK;
   A11Y_TRYBLOCK_END
 }
 STDMETHODIMP
 AccessibleWrap::get_accName(
       /* [optional][in] */ VARIANT varChild,
       /* [retval][out] */ BSTR __RPC_FAR *pszName)
 {
   A11Y_TRYBLOCK_BEGIN
   if (!pszName)
     return E_INVALIDARG;
   *pszName = nullptr;
   if (IsDefunct())
     return CO_E_OBJNOTCONNECTED;
   Accessible* xpAccessible = GetXPAccessibleFor(varChild);
   if (!xpAccessible)
     return E_INVALIDARG;
   if (xpAccessible->IsDefunct())
     return CO_E_OBJNOTCONNECTED;
   nsAutoString name;
   xpAccessible->Name(name);
   // The name was not provided, e.g. no alt attribute for an image. A screen
   // reader may choose to invent its own accessible name, e.g. from an image src
   // attribute. Refer to eNoNameOnPurpose return value.
   if (name.IsVoid())
     return S_FALSE;
   *pszName = ::SysAllocStringLen(name.get(), name.Length());
   if (!*pszName)
     return E_OUTOFMEMORY;
   return S_OK;
   A11Y_TRYBLOCK_END
 }
 STDMETHODIMP
 AccessibleWrap::get_accValue(
       /* [optional][in] */ VARIANT varChild,
       /* [retval][out] */ BSTR __RPC_FAR *pszValue)
 {
   A11Y_TRYBLOCK_BEGIN
   if (!pszValue)
     return E_INVALIDARG;
   *pszValue = nullptr;
   if (IsDefunct())
     return CO_E_OBJNOTCONNECTED;
   Accessible* xpAccessible = GetXPAccessibleFor(varChild);
   if (!xpAccessible)
     return E_INVALIDARG;
   if (xpAccessible->IsDefunct())
     return CO_E_OBJNOTCONNECTED;
   if (xpAccessible->NativeRole() == roles::PASSWORD_TEXT)
     return E_ACCESSDENIED;
   nsAutoString value;
   xpAccessible->Value(value);
   // See bug 438784: need to expose URL on doc's value attribute. For this,
   // reverting part of fix for bug 425693 to make this MSAA method behave
   // IAccessible2-style.
   if (value.IsEmpty())
     return S_FALSE;
   *pszValue = ::SysAllocStringLen(value.get(), value.Length());
   if (!*pszValue)
     return E_OUTOFMEMORY;
   return S_OK;
   A11Y_TRYBLOCK_END
 }
 STDMETHODIMP
 AccessibleWrap::get_accDescription(VARIANT varChild,
                                    BSTR __RPC_FAR *pszDescription)
 {
   A11Y_TRYBLOCK_BEGIN
   if (!pszDescription)
     return E_INVALIDARG;
   *pszDescription = nullptr;
   if (IsDefunct())
     return CO_E_OBJNOTCONNECTED;
   Accessible* xpAccessible = GetXPAccessibleFor(varChild);
   if (!xpAccessible)
     return E_INVALIDARG;
   if (xpAccessible->IsDefunct())
     return CO_E_OBJNOTCONNECTED;
   nsAutoString description;
   xpAccessible->Description(description);
   *pszDescription = ::SysAllocStringLen(description.get(),
                                         description.Length());
   return *pszDescription ? S_OK : E_OUTOFMEMORY;
   A11Y_TRYBLOCK_END
 }
 STDMETHODIMP
 AccessibleWrap::get_accRole(
       /* [optional][in] */ VARIANT varChild,
       /* [retval][out] */ VARIANT __RPC_FAR *pvarRole)
 {
   A11Y_TRYBLOCK_BEGIN
   if (!pvarRole)
     return E_INVALIDARG;
   VariantInit(pvarRole);
   if (IsDefunct())
     return CO_E_OBJNOTCONNECTED;
   Accessible* xpAccessible = GetXPAccessibleFor(varChild);
   if (!xpAccessible)
     return E_INVALIDARG;
   if (xpAccessible->IsDefunct())
     return CO_E_OBJNOTCONNECTED;
 #ifdef DEBUG
   NS_ASSERTION(nsAccUtils::IsTextInterfaceSupportCorrect(xpAccessible),
                "Does not support nsIAccessibleText when it should");
 #endif
   a11y::role geckoRole = xpAccessible->Role();
   uint32_t msaaRole = 0;
 #define ROLE(_geckoRole, stringRole, atkRole, macRole, \
              _msaaRole, ia2Role, nameRule) \
   case roles::_geckoRole: \
     msaaRole = _msaaRole; \
     break;
   switch (geckoRole) {
 #include "RoleMap.h"
     default:
       MOZ_CRASH("Unknown role.");
   };
 #undef ROLE
   // Special case, if there is a ROLE_ROW inside of a ROLE_TREE_TABLE, then call the MSAA role
   // a ROLE_OUTLINEITEM for consistency and compatibility.
   // We need this because ARIA has a role of "row" for both grid and treegrid
   if (geckoRole == roles::ROW) {
     Accessible* xpParent = Parent();
     if (xpParent && xpParent->Role() == roles::TREE_TABLE)
       msaaRole = ROLE_SYSTEM_OUTLINEITEM;
   }
   // -- Try enumerated role
   if (msaaRole != USE_ROLE_STRING) {
     pvarRole->vt = VT_I4;
     pvarRole->lVal = msaaRole;  // Normal enumerated role
     return S_OK;
   }
   // -- Try BSTR role
   // Could not map to known enumerated MSAA role like ROLE_BUTTON
   // Use BSTR role to expose role attribute or tag name + namespace
   nsIContent *content = xpAccessible->GetContent();
   if (!content)
     return E_FAIL;
   if (content->IsElement()) {
     nsAutoString roleString;
     if (msaaRole != ROLE_SYSTEM_CLIENT &&
         !content->GetAttr(kNameSpaceID_None, nsGkAtoms::role, roleString)) {
       nsIDocument * document = content->GetCurrentDoc();
       if (!document)
         return E_FAIL;
       nsINodeInfo *nodeInfo = content->NodeInfo();
       nodeInfo->GetName(roleString);
       // Only append name space if different from that of current document.
       if (!nodeInfo->NamespaceEquals(document->GetDefaultNamespaceID())) {
         nsAutoString nameSpaceURI;
         nodeInfo->GetNamespaceURI(nameSpaceURI);
         roleString += NS_LITERAL_STRING(", ") + nameSpaceURI;
       }
     }
     if (!roleString.IsEmpty()) {
       pvarRole->vt = VT_BSTR;
       pvarRole->bstrVal = ::SysAllocString(roleString.get());
       return S_OK;
     }
   }
   return E_FAIL;
   A11Y_TRYBLOCK_END
 }
 STDMETHODIMP
 AccessibleWrap::get_accState(
       /* [optional][in] */ VARIANT varChild,
       /* [retval][out] */ VARIANT __RPC_FAR *pvarState)
 {
   A11Y_TRYBLOCK_BEGIN
   if (!pvarState)
     return E_INVALIDARG;
   VariantInit(pvarState);
   pvarState->vt = VT_I4;
   pvarState->lVal = 0;
   if (IsDefunct())
     return CO_E_OBJNOTCONNECTED;
   Accessible* xpAccessible = GetXPAccessibleFor(varChild);
   if (!xpAccessible)
     return E_INVALIDARG;
   if (xpAccessible->IsDefunct())
     return CO_E_OBJNOTCONNECTED;
   // MSAA only has 31 states and the lowest 31 bits of our state bit mask
   // are the same states as MSAA.
   // Note: we map the following Gecko states to different MSAA states:
   //   REQUIRED -> ALERT_LOW
   //   ALERT -> ALERT_MEDIUM
   //   INVALID -> ALERT_HIGH
   //   CHECKABLE -> MARQUEED
   uint32_t msaaState = 0;
   nsAccUtils::To32States(xpAccessible->State(), &msaaState, nullptr);
   pvarState->lVal = msaaState;
   return S_OK;
   A11Y_TRYBLOCK_END
 }
 STDMETHODIMP
 AccessibleWrap::get_accHelp(
       /* [optional][in] */ VARIANT varChild,
       /* [retval][out] */ BSTR __RPC_FAR *pszHelp)
 {
   A11Y_TRYBLOCK_BEGIN
   if (!pszHelp)
     return E_INVALIDARG;
   *pszHelp = nullptr;
   return S_FALSE;
   A11Y_TRYBLOCK_END
 }
 STDMETHODIMP
 AccessibleWrap::get_accHelpTopic(
       /* [out] */ BSTR __RPC_FAR *pszHelpFile,
       /* [optional][in] */ VARIANT varChild,
       /* [retval][out] */ long __RPC_FAR *pidTopic)
 {
   A11Y_TRYBLOCK_BEGIN
   if (!pszHelpFile || !pidTopic)
     return E_INVALIDARG;
   *pszHelpFile = nullptr;
   *pidTopic = 0;
   return S_FALSE;
   A11Y_TRYBLOCK_END
 }
 STDMETHODIMP
 AccessibleWrap::get_accKeyboardShortcut(
       /* [optional][in] */ VARIANT varChild,
       /* [retval][out] */ BSTR __RPC_FAR *pszKeyboardShortcut)
 {
   A11Y_TRYBLOCK_BEGIN
   if (!pszKeyboardShortcut)
     return E_INVALIDARG;
   *pszKeyboardShortcut = nullptr;
   if (IsDefunct())
     return CO_E_OBJNOTCONNECTED;
   Accessible* acc = GetXPAccessibleFor(varChild);
   if (!acc)
     return E_INVALIDARG;
   if (acc->IsDefunct())
     return CO_E_OBJNOTCONNECTED;
   KeyBinding keyBinding = acc->AccessKey();
   if (keyBinding.IsEmpty())
     keyBinding = acc->KeyboardShortcut();
   nsAutoString shortcut;
   keyBinding.ToString(shortcut);
   *pszKeyboardShortcut = ::SysAllocStringLen(shortcut.get(),
                                              shortcut.Length());
   return *pszKeyboardShortcut ? S_OK : E_OUTOFMEMORY;
   A11Y_TRYBLOCK_END
 }
 STDMETHODIMP
 AccessibleWrap::get_accFocus(
       /* [retval][out] */ VARIANT __RPC_FAR *pvarChild)
 {
   A11Y_TRYBLOCK_BEGIN
   if (!pvarChild)
     return E_INVALIDARG;
   VariantInit(pvarChild);
   // VT_EMPTY:    None. This object does not have the keyboard focus itself
   //              and does not contain a child that has the keyboard focus.
   // VT_I4:       lVal is CHILDID_SELF. The object itself has the keyboard focus.
   // VT_I4:       lVal contains the child ID of the child element with the keyboard focus.
   // VT_DISPATCH: pdispVal member is the address of the IDispatch interface
   //              for the child object with the keyboard focus.
   if (IsDefunct())
     return CO_E_OBJNOTCONNECTED;
   // Return the current IAccessible child that has focus
   Accessible* focusedAccessible = FocusedChild();
   if (focusedAccessible == this) {
     pvarChild->vt = VT_I4;
     pvarChild->lVal = CHILDID_SELF;
   }
   else if (focusedAccessible) {
     pvarChild->vt = VT_DISPATCH;
     pvarChild->pdispVal = NativeAccessible(focusedAccessible);
   }
   else {
     pvarChild->vt = VT_EMPTY;   // No focus or focus is not a child
   }
   return S_OK;
   A11Y_TRYBLOCK_END
 }
 // This helper class implements IEnumVARIANT for a nsIArray containing nsIAccessible objects.
 class AccessibleEnumerator MOZ_FINAL : public IEnumVARIANT
 {
 public:
   AccessibleEnumerator(nsIArray* aArray) : mArray(aArray), mCurIndex(0) { }
   AccessibleEnumerator(const AccessibleEnumerator& toCopy) :
     mArray(toCopy.mArray), mCurIndex(toCopy.mCurIndex) { }
   ~AccessibleEnumerator() { }
   // IUnknown
   DECL_IUNKNOWN
   // IEnumVARIANT
   STDMETHODIMP Next(unsigned long celt, VARIANT FAR* rgvar, unsigned long FAR* pceltFetched);
   STDMETHODIMP Skip(unsigned long celt);
   STDMETHODIMP Reset()
   {
     mCurIndex = 0;
     return S_OK;
   }
   STDMETHODIMP Clone(IEnumVARIANT FAR* FAR* ppenum);
 private:
   nsCOMPtr<nsIArray> mArray;
   uint32_t mCurIndex;
 };
 STDMETHODIMP
 AccessibleEnumerator::QueryInterface(REFIID iid, void ** ppvObject)
 {
   A11Y_TRYBLOCK_BEGIN
   if (iid == IID_IEnumVARIANT) {
     *ppvObject = static_cast<IEnumVARIANT*>(this);
     AddRef();
     return S_OK;
   }
   if (iid == IID_IUnknown) {
     *ppvObject = static_cast<IUnknown*>(this);
     AddRef();
     return S_OK;
   }
   *ppvObject = nullptr;
   return E_NOINTERFACE;
   A11Y_TRYBLOCK_END
 }
 STDMETHODIMP
 AccessibleEnumerator::Next(unsigned long celt, VARIANT FAR* rgvar, unsigned long FAR* pceltFetched)
 {
   A11Y_TRYBLOCK_BEGIN
   uint32_t length = 0;
   mArray->GetLength(&length);
   HRESULT hr = S_OK;
   // Can't get more elements than there are...
   if (celt > length - mCurIndex) {
     hr = S_FALSE;
     celt = length - mCurIndex;
   }
   for (uint32_t i = 0; i < celt; ++i, ++mCurIndex) {
     // Copy the elements of the array into rgvar
     nsCOMPtr<nsIAccessible> accel(do_QueryElementAt(mArray, mCurIndex));
     NS_ASSERTION(accel, "Invalid pointer in mArray");
     if (accel) {
       rgvar[i].vt = VT_DISPATCH;
       rgvar[i].pdispVal = AccessibleWrap::NativeAccessible(accel);
     }
   }
   if (pceltFetched)
     *pceltFetched = celt;
   return hr;
   A11Y_TRYBLOCK_END
 }
 STDMETHODIMP
 AccessibleEnumerator::Clone(IEnumVARIANT FAR* FAR* ppenum)
 {
   A11Y_TRYBLOCK_BEGIN
   *ppenum = new AccessibleEnumerator(*this);
   if (!*ppenum)
     return E_OUTOFMEMORY;
   NS_ADDREF(*ppenum);
   return S_OK;
   A11Y_TRYBLOCK_END
 }
 STDMETHODIMP
 AccessibleEnumerator::Skip(unsigned long celt)
 {
   A11Y_TRYBLOCK_BEGIN
   uint32_t length = 0;
   mArray->GetLength(&length);
   // Check if we can skip the requested number of elements
   if (celt > length - mCurIndex) {
     mCurIndex = length;
     return S_FALSE;
   }
   mCurIndex += celt;
   return S_OK;
   A11Y_TRYBLOCK_END
 }
 /**
   * This method is called when a client wants to know which children of a node
   *  are selected. Note that this method can only find selected children for
   *  nsIAccessible object which implement SelectAccessible.
   *
   * The VARIANT return value arguement is expected to either contain a single IAccessible
   *  or an IEnumVARIANT of IAccessibles. We return the IEnumVARIANT regardless of the number
   *  of children selected, unless there are none selected in which case we return an empty
   *  VARIANT.
   *
   * We get the selected options from the select's accessible object and wrap
   *  those in an AccessibleEnumerator which we then put in the return VARIANT.
   *
   * returns a VT_EMPTY VARIANT if:
   *  - there are no selected children for this object
   *  - the object is not the type that can have children selected
   */
 STDMETHODIMP
 AccessibleWrap::get_accSelection(VARIANT __RPC_FAR *pvarChildren)
 {
   A11Y_TRYBLOCK_BEGIN
   if (!pvarChildren)
     return E_INVALIDARG;
   VariantInit(pvarChildren);
   pvarChildren->vt = VT_EMPTY;
   if (IsDefunct())
     return CO_E_OBJNOTCONNECTED;
   if (IsSelect()) {
     nsCOMPtr<nsIArray> selectedItems = SelectedItems();
     if (selectedItems) {
       // 1) Create and initialize the enumeration
       nsRefPtr<AccessibleEnumerator> pEnum =
         new AccessibleEnumerator(selectedItems);
       // 2) Put the enumerator in the VARIANT
       if (!pEnum)
         return E_OUTOFMEMORY;
       pvarChildren->vt = VT_UNKNOWN;    // this must be VT_UNKNOWN for an IEnumVARIANT
       NS_ADDREF(pvarChildren->punkVal = pEnum);
     }
   }
   return S_OK;
   A11Y_TRYBLOCK_END
 }
 STDMETHODIMP
 AccessibleWrap::get_accDefaultAction(
       /* [optional][in] */ VARIANT varChild,
       /* [retval][out] */ BSTR __RPC_FAR *pszDefaultAction)
 {
   A11Y_TRYBLOCK_BEGIN
   if (!pszDefaultAction)
     return E_INVALIDARG;
   *pszDefaultAction = nullptr;
   if (IsDefunct())
     return CO_E_OBJNOTCONNECTED;
   Accessible* xpAccessible = GetXPAccessibleFor(varChild);
   if (!xpAccessible)
     return E_INVALIDARG;
   if (xpAccessible->IsDefunct())
     return CO_E_OBJNOTCONNECTED;
   nsAutoString defaultAction;
   if (NS_FAILED(xpAccessible->GetActionName(0, defaultAction)))
     return E_FAIL;
   *pszDefaultAction = ::SysAllocStringLen(defaultAction.get(),
                                           defaultAction.Length());
   return *pszDefaultAction ? S_OK : E_OUTOFMEMORY;
   A11Y_TRYBLOCK_END
 }
 STDMETHODIMP
 AccessibleWrap::accSelect(
       /* [in] */ long flagsSelect,
       /* [optional][in] */ VARIANT varChild)
 {
   A11Y_TRYBLOCK_BEGIN
   if (IsDefunct())
     return CO_E_OBJNOTCONNECTED;
   // currently only handle focus and selection
   Accessible* xpAccessible = GetXPAccessibleFor(varChild);
   if (!xpAccessible)
     return E_INVALIDARG;
   if (xpAccessible->IsDefunct())
     return CO_E_OBJNOTCONNECTED;
   if (flagsSelect & (SELFLAG_TAKEFOCUS|SELFLAG_TAKESELECTION|SELFLAG_REMOVESELECTION))
   {
     if (flagsSelect & SELFLAG_TAKEFOCUS)
       xpAccessible->TakeFocus();
     if (flagsSelect & SELFLAG_TAKESELECTION)
       xpAccessible->TakeSelection();
     if (flagsSelect & SELFLAG_ADDSELECTION)
       xpAccessible->SetSelected(true);
     if (flagsSelect & SELFLAG_REMOVESELECTION)
       xpAccessible->SetSelected(false);
     if (flagsSelect & SELFLAG_EXTENDSELECTION)
       xpAccessible->ExtendSelection();
     return S_OK;
   }
   return E_FAIL;
   A11Y_TRYBLOCK_END
 }
 STDMETHODIMP
 AccessibleWrap::accLocation(
       /* [out] */ long __RPC_FAR *pxLeft,
       /* [out] */ long __RPC_FAR *pyTop,
       /* [out] */ long __RPC_FAR *pcxWidth,
       /* [out] */ long __RPC_FAR *pcyHeight,
       /* [optional][in] */ VARIANT varChild)
 {
   A11Y_TRYBLOCK_BEGIN
   if (!pxLeft || !pyTop || !pcxWidth || !pcyHeight)
     return E_INVALIDARG;
   *pxLeft = 0;
   *pyTop = 0;
   *pcxWidth = 0;
   *pcyHeight = 0;
   if (IsDefunct())
     return CO_E_OBJNOTCONNECTED;
   Accessible* xpAccessible = GetXPAccessibleFor(varChild);
   if (!xpAccessible)
     return E_INVALIDARG;
   if (xpAccessible->IsDefunct())
     return CO_E_OBJNOTCONNECTED;
   int32_t x, y, width, height;
   if (NS_FAILED(xpAccessible->GetBounds(&x, &y, &width, &height)))
     return E_FAIL;
   *pxLeft = x;
   *pyTop = y;
   *pcxWidth = width;
   *pcyHeight = height;
   return S_OK;
   A11Y_TRYBLOCK_END
 }
 STDMETHODIMP
 AccessibleWrap::accNavigate(
       /* [in] */ long navDir,
       /* [optional][in] */ VARIANT varStart,
       /* [retval][out] */ VARIANT __RPC_FAR *pvarEndUpAt)
 {
   A11Y_TRYBLOCK_BEGIN
   if (!pvarEndUpAt)
     return E_INVALIDARG;
   VariantInit(pvarEndUpAt);
   if (IsDefunct())
     return CO_E_OBJNOTCONNECTED;
   Accessible* accessible = GetXPAccessibleFor(varStart);
   if (!accessible)
     return E_INVALIDARG;
   if (accessible->IsDefunct())
     return CO_E_OBJNOTCONNECTED;
   Accessible* navAccessible = nullptr;
   Maybe<RelationType> xpRelation;
 #define RELATIONTYPE(geckoType, stringType, atkType, msaaType, ia2Type) \
   case msaaType: \
     xpRelation.construct(RelationType::geckoType); \
     break;
   switch(navDir) {
     case NAVDIR_FIRSTCHILD:
       if (!nsAccUtils::MustPrune(accessible))
         navAccessible = accessible->FirstChild();
       break;
     case NAVDIR_LASTCHILD:
       if (!nsAccUtils::MustPrune(accessible))
         navAccessible = accessible->LastChild();
       break;
     case NAVDIR_NEXT:
       navAccessible = accessible->NextSibling();
       break;
     case NAVDIR_PREVIOUS:
       navAccessible = accessible->PrevSibling();
       break;
     case NAVDIR_DOWN:
     case NAVDIR_LEFT:
     case NAVDIR_RIGHT:
     case NAVDIR_UP:
       return E_NOTIMPL;
     // MSAA relationship extensions to accNavigate
 #include "RelationTypeMap.h"
     default:
       return E_INVALIDARG;
   }
 #undef RELATIONTYPE
   pvarEndUpAt->vt = VT_EMPTY;
   if (!xpRelation.empty()) {
     Relation rel = RelationByType(xpRelation.ref());
     navAccessible = rel.Next();
   }
   if (!navAccessible)
     return E_FAIL;
   pvarEndUpAt->pdispVal = NativeAccessible(navAccessible);
   pvarEndUpAt->vt = VT_DISPATCH;
   return S_OK;
   A11Y_TRYBLOCK_END
 }
 STDMETHODIMP
 AccessibleWrap::accHitTest(
       /* [in] */ long xLeft,
       /* [in] */ long yTop,
       /* [retval][out] */ VARIANT __RPC_FAR *pvarChild)
 {
   A11Y_TRYBLOCK_BEGIN
   if (!pvarChild)
     return E_INVALIDARG;
   VariantInit(pvarChild);
   if (IsDefunct())
     return CO_E_OBJNOTCONNECTED;
   Accessible* accessible = ChildAtPoint(xLeft, yTop, eDirectChild);
   // if we got a child
   if (accessible) {
     // if the child is us
     if (accessible == this) {
       pvarChild->vt = VT_I4;
       pvarChild->lVal = CHILDID_SELF;
     } else { // its not create an Accessible for it.
       pvarChild->vt = VT_DISPATCH;
       pvarChild->pdispVal = NativeAccessible(accessible);
     }
   } else {
     // no child at that point
     pvarChild->vt = VT_EMPTY;
     return S_FALSE;
   }
   return S_OK;
   A11Y_TRYBLOCK_END
 }
 STDMETHODIMP
 AccessibleWrap::accDoDefaultAction(
       /* [optional][in] */ VARIANT varChild)
 {
   A11Y_TRYBLOCK_BEGIN
   if (IsDefunct())
     return CO_E_OBJNOTCONNECTED;
   Accessible* xpAccessible = GetXPAccessibleFor(varChild);
   if (!xpAccessible)
     return E_INVALIDARG;
   if (xpAccessible->IsDefunct())
     return CO_E_OBJNOTCONNECTED;
   return GetHRESULT(xpAccessible->DoAction(0));
   A11Y_TRYBLOCK_END
 }
 STDMETHODIMP
 AccessibleWrap::put_accName(
       /* [optional][in] */ VARIANT varChild,
       /* [in] */ BSTR szName)
 {
   return E_NOTIMPL;
 }
 STDMETHODIMP
 AccessibleWrap::put_accValue(
       /* [optional][in] */ VARIANT varChild,
       /* [in] */ BSTR szValue)
 {
   return E_NOTIMPL;
 }
 ////////////////////////////////////////////////////////////////////////////////
 // IDispatch
 STDMETHODIMP
 AccessibleWrap::GetTypeInfoCount(UINT *pctinfo)
 {
   if (!pctinfo)
     return E_INVALIDARG;
   *pctinfo = 1;
   return S_OK;
 }
 STDMETHODIMP
 AccessibleWrap::GetTypeInfo(UINT iTInfo, LCID lcid, ITypeInfo **ppTInfo)
 {
   if (!ppTInfo)
     return E_INVALIDARG;
   *ppTInfo = nullptr;
   if (iTInfo != 0)
     return DISP_E_BADINDEX;
   ITypeInfo * typeInfo = GetTI(lcid);
   if (!typeInfo)
     return E_FAIL;
   typeInfo->AddRef();
   *ppTInfo = typeInfo;
   return S_OK;
 }
 STDMETHODIMP
 AccessibleWrap::GetIDsOfNames(REFIID riid, LPOLESTR *rgszNames,
                               UINT cNames, LCID lcid, DISPID *rgDispId)
 {
   ITypeInfo *typeInfo = GetTI(lcid);
   if (!typeInfo)
     return E_FAIL;
   HRESULT hr = DispGetIDsOfNames(typeInfo, rgszNames, cNames, rgDispId);
   return hr;
 }
 STDMETHODIMP
 AccessibleWrap::Invoke(DISPID dispIdMember, REFIID riid,
                        LCID lcid, WORD wFlags, DISPPARAMS *pDispParams,
                        VARIANT *pVarResult, EXCEPINFO *pExcepInfo,
                        UINT *puArgErr)
 {
   ITypeInfo *typeInfo = GetTI(lcid);
   if (!typeInfo)
     return E_FAIL;
   return typeInfo->Invoke(static_cast<IAccessible*>(this), dispIdMember,
                           wFlags, pDispParams, pVarResult, pExcepInfo,
                           puArgErr);
 }
 // nsIAccessible method
 NS_IMETHODIMP
 AccessibleWrap::GetNativeInterface(void **aOutAccessible)
 {
   *aOutAccessible = static_cast<IAccessible*>(this);
   NS_ADDREF_THIS();
   return NS_OK;
 }
 ////////////////////////////////////////////////////////////////////////////////
 // Accessible
 nsresult
 AccessibleWrap::HandleAccEvent(AccEvent* aEvent)
 {
   nsresult rv = Accessible::HandleAccEvent(aEvent);
   NS_ENSURE_SUCCESS(rv, rv);
   // Don't fire native MSAA events or mess with the system caret
   // when running in metro mode. This confuses input focus tracking
   // in metro's UIA implementation.
   if (XRE_GetWindowsEnvironment() == WindowsEnvironmentType_Metro) {
     return NS_OK;
   }
   uint32_t eventType = aEvent->GetEventType();
   static_assert(sizeof(gWinEventMap)/sizeof(gWinEventMap[0]) == nsIAccessibleEvent::EVENT_LAST_ENTRY,
                 "MSAA event map skewed");
   NS_ENSURE_TRUE(eventType > 0 && eventType < ArrayLength(gWinEventMap), NS_ERROR_FAILURE);
   uint32_t winEvent = gWinEventMap[eventType];
   if (!winEvent)
     return NS_OK;
   // Means we're not active.
   NS_ENSURE_TRUE(!IsDefunct(), NS_ERROR_FAILURE);
   Accessible* accessible = aEvent->GetAccessible();
   if (!accessible)
     return NS_OK;
   if (eventType == nsIAccessibleEvent::EVENT_TEXT_CARET_MOVED ||
       eventType == nsIAccessibleEvent::EVENT_FOCUS) {
     UpdateSystemCaretFor(accessible);
   }
   int32_t childID = GetChildIDFor(accessible); // get the id for the accessible
   if (!childID)
     return NS_OK; // Can't fire an event without a child ID
   HWND hWnd = GetHWNDFor(accessible);
   NS_ENSURE_TRUE(hWnd, NS_ERROR_FAILURE);
   nsAutoString tag;
   nsAutoCString id;
   nsIContent* cnt = accessible->GetContent();
   if (cnt) {
     cnt->Tag()->ToString(tag);
     nsIAtom* aid = cnt->GetID();
     if (aid)
       aid->ToUTF8String(id);
   }
 #ifdef A11Y_LOG
   if (logging::IsEnabled(logging::ePlatforms)) {
     printf("\n\nMSAA event: event: %d, target: %s@id='%s', childid: %d, hwnd: %d\n\n",
            eventType, NS_ConvertUTF16toUTF8(tag).get(), id.get(),
            childID, hWnd);
   }
 #endif
   // Fire MSAA event for client area window.
   ::NotifyWinEvent(winEvent, hWnd, OBJID_CLIENT, childID);
   // JAWS announces collapsed combobox navigation based on focus events.
   if (Compatibility::IsJAWS()) {
     if (eventType == nsIAccessibleEvent::EVENT_SELECTION &&
       accessible->Role() == roles::COMBOBOX_OPTION) {
       ::NotifyWinEvent(EVENT_OBJECT_FOCUS, hWnd, OBJID_CLIENT, childID);
     }
   }
   return NS_OK;
 }
 ////////////////////////////////////////////////////////////////////////////////
 // AccessibleWrap
 //------- Helper methods ---------
 int32_t
 AccessibleWrap::GetChildIDFor(Accessible* aAccessible)
 {
   // A child ID of the window is required, when we use NotifyWinEvent,
   // so that the 3rd party application can call back and get the IAccessible
   // the event occurred on.
   // Yes, this means we're only compatibible with 32 bit
   // MSAA is only available for 32 bit windows, so it's okay
   // XXX: bug 606080
   return aAccessible ? - NS_PTR_TO_INT32(aAccessible->UniqueID()) : 0;
 }
 HWND
 AccessibleWrap::GetHWNDFor(Accessible* aAccessible)
 {
   if (aAccessible) {
     DocAccessible* document = aAccessible->Document();
     if(!document)
       return nullptr;
     // Popup lives in own windows, use its HWND until the popup window is
     // hidden to make old JAWS versions work with collapsed comboboxes (see
     // discussion in bug 379678).
     nsIFrame* frame = aAccessible->GetFrame();
     if (frame) {
       nsIWidget* widget = frame->GetNearestWidget();
       if (widget && widget->IsVisible()) {
         nsIPresShell* shell = document->PresShell();
         nsViewManager* vm = shell->GetViewManager();
         if (vm) {
           nsCOMPtr<nsIWidget> rootWidget;
           vm->GetRootWidget(getter_AddRefs(rootWidget));
           // Make sure the accessible belongs to popup. If not then use
           // document HWND (which might be different from root widget in the
           // case of window emulation).
           if (rootWidget != widget)
             return static_cast<HWND>(widget->GetNativeData(NS_NATIVE_WINDOW));
         }
       }
     }
     return static_cast<HWND>(document->GetNativeWindow());
   }
   return nullptr;
 }
 IDispatch*
 AccessibleWrap::NativeAccessible(nsIAccessible* aAccessible)
 {
   if (!aAccessible) {
    NS_WARNING("Not passing in an aAccessible");
    return nullptr;
   }
   IAccessible* msaaAccessible = nullptr;
   aAccessible->GetNativeInterface(reinterpret_cast<void**>(&msaaAccessible));
   return static_cast<IDispatch*>(msaaAccessible);
 }
 Accessible*
 AccessibleWrap::GetXPAccessibleFor(const VARIANT& aVarChild)
 {
   if (aVarChild.vt != VT_I4)
     return nullptr;
   // if its us real easy - this seems to always be the case
   if (aVarChild.lVal == CHILDID_SELF)
     return this;
   if (nsAccUtils::MustPrune(this))
     return nullptr;
   // If lVal negative then it is treated as child ID and we should look for
   // accessible through whole accessible subtree including subdocuments.
   // Otherwise we treat lVal as index in parent.
   if (aVarChild.lVal < 0) {
     // Convert child ID to unique ID.
     void* uniqueID = reinterpret_cast<void*>(-aVarChild.lVal);
     DocAccessible* document = Document();
     Accessible* child =
       document->GetAccessibleByUniqueIDInSubtree(uniqueID);
     // If it is a document then just return an accessible.
     if (IsDoc())
       return child;
     // Otherwise check whether the accessible is a child (this path works for
     // ARIA documents and popups).
     Accessible* parent = child;
     while (parent && parent != document) {
       if (parent == this)
         return child;
       parent = parent->Parent();
     }
     return nullptr;
   }
   // Gecko child indices are 0-based in contrast to indices used in MSAA.
   return GetChildAt(aVarChild.lVal - 1);
 }
 void
 AccessibleWrap::UpdateSystemCaretFor(Accessible* aAccessible)
 {
   // Move the system caret so that Windows Tablet Edition and tradional ATs with
   // off-screen model can follow the caret
   ::DestroyCaret();
   HyperTextAccessible* text = aAccessible->AsHyperText();
   if (!text)
     return;
   nsIWidget* widget = nullptr;
   nsIntRect caretRect = text->GetCaretRect(&widget);
   HWND caretWnd;
   if (caretRect.IsEmpty() || !(caretWnd = (HWND)widget->GetNativeData(NS_NATIVE_WINDOW))) {
     return;
   }
   // Create invisible bitmap for caret, otherwise its appearance interferes
   // with Gecko caret
   HBITMAP caretBitMap = CreateBitmap(1, caretRect.height, 1, 1, nullptr);
   if (::CreateCaret(caretWnd, caretBitMap, 1, caretRect.height)) {  // Also destroys the last caret
     ::ShowCaret(caretWnd);
     RECT windowRect;
     ::GetWindowRect(caretWnd, &windowRect);
     ::SetCaretPos(caretRect.x - windowRect.left, caretRect.y - windowRect.top);
     ::DeleteObject(caretBitMap);
   }
 }
 ITypeInfo*
 AccessibleWrap::GetTI(LCID lcid)
 {
   if (gTypeInfo)
     return gTypeInfo;
   ITypeLib *typeLib = nullptr;
   HRESULT hr = LoadRegTypeLib(LIBID_Accessibility, 1, 0, lcid, &typeLib);
   if (FAILED(hr))
     return nullptr;
   hr = typeLib->GetTypeInfoOfGuid(IID_IAccessible, &gTypeInfo);
   typeLib->Release();
   if (FAILED(hr))
     return nullptr;
   return gTypeInfo;
 }

The Tor Browser / annotate

accessible/src/windows/msaa/AccessibleWrap.cpp@6474c204b198 (annotated)

accessible/src/windows/msaa/AccessibleWrap.cpp