C++ AccessibleWrap::QueryInterface方法代码示例

STDMETHODIMP
sdnAccessible::QueryInterface(REFIID aREFIID, void** aInstancePtr)
{
  if (!aInstancePtr)
    return E_FAIL;
  *aInstancePtr = nullptr;

  if (aREFIID == IID_ISimpleDOMNode) {
    *aInstancePtr = static_cast<ISimpleDOMNode*>(this);
    AddRef();
    return S_OK;
  }

  AccessibleWrap* accessible = static_cast<AccessibleWrap*>(GetAccessible());
  if (accessible)
    return accessible->QueryInterface(aREFIID, aInstancePtr);

  // IUnknown* is the canonical one if and only if this accessible doesn't have
  // an accessible.
  if (aREFIID == IID_IUnknown) {
    *aInstancePtr = static_cast<ISimpleDOMNode*>(this);
    AddRef();
    return S_OK;
  }

  return E_NOINTERFACE;
}

STDMETHODIMP
ia2AccessibleHyperlink::get_anchor(long aIndex, VARIANT* aAnchor)
{
  A11Y_TRYBLOCK_BEGIN

  VariantInit(aAnchor);

  Accessible* thisObj = static_cast<AccessibleWrap*>(this);
  if (thisObj->IsDefunct())
    return CO_E_OBJNOTCONNECTED;

  if (aIndex < 0 || aIndex >= static_cast<long>(thisObj->AnchorCount()))
    return E_INVALIDARG;

  if (!thisObj->IsLink())
    return S_FALSE;

  AccessibleWrap* anchor =
    static_cast<AccessibleWrap*>(thisObj->AnchorAt(aIndex));
  if (!anchor)
    return S_FALSE;

  void* instancePtr = nullptr;
  HRESULT result = anchor->QueryInterface(IID_IUnknown, &instancePtr);
  if (FAILED(result))
    return result;

  IUnknown* unknownPtr = static_cast<IUnknown*>(instancePtr);
  aAnchor->ppunkVal = &unknownPtr;
  aAnchor->vt = VT_UNKNOWN;
  return S_OK;

  A11Y_TRYBLOCK_END
}

STDMETHODIMP
sdnAccessible::QueryInterface(REFIID aREFIID, void** aInstancePtr)
{
  if (!aInstancePtr)
    return E_FAIL;
  *aInstancePtr = nullptr;

  if (aREFIID == IID_IClientSecurity) {
    // Some code might QI(IID_IClientSecurity) to detect whether or not we are
    // a proxy. Right now that can potentially happen off the main thread, so we
    // look for this condition immediately so that we don't trigger other code
    // that might not be thread-safe.
    return E_NOINTERFACE;
  }

  if (aREFIID == IID_ISimpleDOMNode) {
    *aInstancePtr = static_cast<ISimpleDOMNode*>(this);
    AddRef();
    return S_OK;
  }

  AccessibleWrap* accessible = GetAccessible();
  if (accessible)
    return accessible->QueryInterface(aREFIID, aInstancePtr);

  // IUnknown* is the canonical one if and only if this accessible doesn't have
  // an accessible.
  if (aREFIID == IID_IUnknown) {
    *aInstancePtr = static_cast<ISimpleDOMNode*>(this);
    AddRef();
    return S_OK;
  }

  return E_NOINTERFACE;
}

static gint
getSelectedRowsCB(AtkTable *aTable, gint **aSelected)
{
    AccessibleWrap* accWrap = GetAccessibleWrap(ATK_OBJECT(aTable));
    if (!accWrap)
        return 0;

    nsCOMPtr<nsIAccessibleTable> accTable;
    accWrap->QueryInterface(NS_GET_IID(nsIAccessibleTable),
                            getter_AddRefs(accTable));
    NS_ENSURE_TRUE(accTable, 0);

    PRUint32 size = 0;
    PRInt32 *rows = NULL;
    nsresult rv = accTable->GetSelectedRowIndices(&size, &rows);
    if (NS_FAILED(rv) || (size == 0) || !rows) {
        *aSelected = nsnull;
        return 0;
    }

    gint *atkRows = g_new(gint, size);
    if (!atkRows) {
        NS_WARNING("OUT OF MEMORY");
        return 0;
    }

    //copy
    for (PRUint32 index = 0; index < size; ++index)
        atkRows[index] = static_cast<gint>(rows[index]);
    nsMemory::Free(rows);

    *aSelected = atkRows;
    return size;
}

static gboolean
isCellSelectedCB(AtkTable *aTable, gint aRow, gint aColumn)
{
  AccessibleWrap* accWrap = GetAccessibleWrap(ATK_OBJECT(aTable));
  if (!accWrap)
    return FALSE;

    nsCOMPtr<nsIAccessibleTable> accTable;
    accWrap->QueryInterface(NS_GET_IID(nsIAccessibleTable),
                            getter_AddRefs(accTable));
    NS_ENSURE_TRUE(accTable, FALSE);

    bool outValue;
    nsresult rv = accTable->IsCellSelected(aRow, aColumn, &outValue);
    return NS_FAILED(rv) ? FALSE : static_cast<gboolean>(outValue);
}

static const gchar*
getRowDescriptionCB(AtkTable *aTable, gint aRow)
{
  AccessibleWrap* accWrap = GetAccessibleWrap(ATK_OBJECT(aTable));
  if (!accWrap)
    return nsnull;

    nsCOMPtr<nsIAccessibleTable> accTable;
    accWrap->QueryInterface(NS_GET_IID(nsIAccessibleTable),
                            getter_AddRefs(accTable));
    NS_ENSURE_TRUE(accTable, nsnull);

    nsAutoString autoStr;
    nsresult rv = accTable->GetRowDescription(aRow, autoStr);
    NS_ENSURE_SUCCESS(rv, nsnull);

    return AccessibleWrap::ReturnString(autoStr);
}

static AtkObject*
getRowHeaderCB(AtkTable *aTable, gint aRow)
{
  AccessibleWrap* accWrap = GetAccessibleWrap(ATK_OBJECT(aTable));
  if (!accWrap)
    return nsnull;

    nsCOMPtr<nsIAccessibleTable> accTable;
    accWrap->QueryInterface(NS_GET_IID(nsIAccessibleTable),
                            getter_AddRefs(accTable));
    NS_ENSURE_TRUE(accTable, nsnull);

    nsCOMPtr<nsIAccessible> accCell;
    accTable->GetCellAt(aRow, 0, getter_AddRefs(accCell));
    if (!accCell)
      return nsnull;

    // If the cell at the first column is row header then assume it is row
    // header for all columns,
    if (nsAccUtils::Role(accCell) == nsIAccessibleRole::ROLE_ROWHEADER)
        return AccessibleWrap::GetAtkObject(accCell);

    // otherwise get row header for the data cell at the first column.
    nsCOMPtr<nsIAccessibleTableCell> accTableCell =
        do_QueryInterface(accCell);

    if (accTableCell) {
      nsCOMPtr<nsIArray> headerCells;
      accTableCell->GetRowHeaderCells(getter_AddRefs(headerCells));
      if (headerCells) {
        nsresult rv;
        nsCOMPtr<nsIAccessible> accHeaderCell =
            do_QueryElementAt(headerCells, 0, &rv);
        NS_ENSURE_SUCCESS(rv, nsnull);

        return AccessibleWrap::GetAtkObject(accHeaderCell);
      }
    }

    return nsnull;
}