accessible/windows/msaa/RootAccessibleWrap.cpp
author imoraru <imoraru@mozilla.com>
Thu, 29 Apr 2021 15:51:36 +0300
changeset 577971 2a4d3f13161de6a01d6c29b7c92658d74748ff67
parent 577957 70b71a3501519055e3564c3d5c9dd31155b9127a
child 578256 f967d16a75ae1166184e823294271630a4fb2783
permissions -rw-r--r--
Backed out 6 changesets (bug 1694865) for causing merge conflict. Backed out changeset 1a948c0ec982 (bug 1694865) Backed out changeset 3ea7b46bb4f8 (bug 1694865) Backed out changeset 702b601cc6fc (bug 1694865) Backed out changeset 70b71a350151 (bug 1694865) Backed out changeset 61aad68338f7 (bug 1694865) Backed out changeset 62137fbc81cf (bug 1694865)

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 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 "RootAccessibleWrap.h"

#include "Compatibility.h"
#include "mozilla/PresShell.h"
#include "mozilla/WindowsVersion.h"
#include "nsCoreUtils.h"
#include "nsWinUtils.h"
#include "Relation.h"

using namespace mozilla;
using namespace mozilla::a11y;

////////////////////////////////////////////////////////////////////////////////
// Constructor/destructor

RootAccessibleWrap::RootAccessibleWrap(dom::Document* aDocument,
                                       PresShell* aPresShell)
    : RootAccessible(aDocument, aPresShell), mOuter(&mInternalUnknown) {}

RootAccessibleWrap::~RootAccessibleWrap() {}

////////////////////////////////////////////////////////////////////////////////
// Aggregated IUnknown
HRESULT
RootAccessibleWrap::InternalQueryInterface(REFIID aIid, void** aOutInterface) {
  if (!aOutInterface) {
    return E_INVALIDARG;
  }

  // InternalQueryInterface should always return its internal unknown
  // when queried for IID_IUnknown...
  if (aIid == IID_IUnknown) {
    RefPtr<IUnknown> punk(&mInternalUnknown);
    punk.forget(aOutInterface);
    return S_OK;
  }

  // ...Otherwise we pass through to the base COM implementation of
  // QueryInterface which is provided by DocAccessibleWrap.
  return DocAccessibleWrap::QueryInterface(aIid, aOutInterface);
}

ULONG
RootAccessibleWrap::InternalAddRef() { return DocAccessible::AddRef(); }

ULONG
RootAccessibleWrap::InternalRelease() { return DocAccessible::Release(); }

already_AddRefed<IUnknown> RootAccessibleWrap::Aggregate(IUnknown* aOuter) {
  MOZ_ASSERT(mOuter &&
             (mOuter == &mInternalUnknown || mOuter == aOuter || !aOuter));
  if (!aOuter) {
    // If there is no aOuter then we should always set mOuter to
    // mInternalUnknown. This is standard COM aggregation stuff.
    mOuter = &mInternalUnknown;
    return nullptr;
  }

  mOuter = aOuter;
  return GetInternalUnknown();
}

already_AddRefed<IUnknown> RootAccessibleWrap::GetInternalUnknown() {
  RefPtr<IUnknown> result(&mInternalUnknown);
  return result.forget();
}

////////////////////////////////////////////////////////////////////////////////
// RootAccessible

void RootAccessibleWrap::DocumentActivated(DocAccessible* aDocument) {
  // This check will never work with e10s enabled, in other words, as of
  // Firefox 57.
  if (Compatibility::IsDolphin() &&
      nsCoreUtils::IsTopLevelContentDocInProcess(aDocument->DocumentNode())) {
    MOZ_ASSERT(XRE_IsParentProcess());
    uint32_t count = mChildDocuments.Length();
    for (uint32_t idx = 0; idx < count; idx++) {
      DocAccessible* childDoc = mChildDocuments[idx];
      HWND childDocHWND = static_cast<HWND>(childDoc->GetNativeWindow());
      if (childDoc != aDocument)
        nsWinUtils::HideNativeWindow(childDocHWND);
      else
        nsWinUtils::ShowNativeWindow(childDocHWND);
    }
  }
}

STDMETHODIMP
RootAccessibleWrap::accNavigate(
    /* [in] */ long navDir,
    /* [optional][in] */ VARIANT varStart,
    /* [retval][out] */ VARIANT __RPC_FAR* pvarEndUpAt) {
  // Special handling for NAVRELATION_EMBEDS.
  // When we only have a single process, this can be handled the same way as
  // any other relation.
  // However, for multi process, the normal relation mechanism doesn't work
  // because it can't handle remote objects.
  if (navDir != NAVRELATION_EMBEDS || varStart.vt != VT_I4 ||
      varStart.lVal != CHILDID_SELF) {
    // We only handle EMBEDS on the root here.
    // Forward to the base implementation.
    return DocAccessibleWrap::accNavigate(navDir, varStart, pvarEndUpAt);
  }

  if (!pvarEndUpAt) {
    return E_INVALIDARG;
  }
  if (IsDefunct()) {
    return CO_E_OBJNOTCONNECTED;
  }

  LocalAccessible* target = nullptr;
  // Get the document in the active tab.
  RemoteAccessible* docProxy = GetPrimaryRemoteTopLevelContentDoc();
  if (docProxy) {
    target = WrapperFor(docProxy);
  } else {
    // The base implementation could handle this, but we may as well
    // just handle it here.
    Relation rel = RelationByType(RelationType::EMBEDS);
    target = rel.Next();
  }

  if (!target) {
    return E_FAIL;
  }

  VariantInit(pvarEndUpAt);
  pvarEndUpAt->pdispVal = NativeAccessible(target);
  pvarEndUpAt->vt = VT_DISPATCH;
  return S_OK;
}

STDMETHODIMP
RootAccessibleWrap::get_accFocus(
    /* [retval][out] */ VARIANT __RPC_FAR* pvarChild) {
  HRESULT hr = DocAccessibleWrap::get_accFocus(pvarChild);
  if (FAILED(hr) || pvarChild->vt != VT_EMPTY || !IsWin8OrLater()) {
    // 1. We got a definite result (either failure or an accessible); or
    // 2. This is Windows 7, where we don't want to retrieve the focus from a
    // remote document because this causes mysterious intermittent crashes
    // when we're called by UIA clients; see bug 1424505.
    return hr;
  }

  // The base implementation reported no focus.
  // Focus might be in a remote document.
  // (The base implementation can't handle this.)
  // Get the document in the active tab.
  RemoteAccessible* docProxy = GetPrimaryRemoteTopLevelContentDoc();
  if (!docProxy) {
    return hr;
  }
  LocalAccessible* docAcc = WrapperFor(docProxy);
  if (!docAcc) {
    return E_FAIL;
  }
  RefPtr<IDispatch> docDisp = NativeAccessible(docAcc);
  if (!docDisp) {
    return E_FAIL;
  }
  RefPtr<IAccessible> docIa;
  hr = docDisp->QueryInterface(IID_IAccessible, (void**)getter_AddRefs(docIa));
  MOZ_ASSERT(SUCCEEDED(hr));
  MOZ_ASSERT(docIa);

  // Ask this document for its focused descendant.
  // We return this as is to the client except for CHILDID_SELF (see below).
  hr = docIa->get_accFocus(pvarChild);
  if (FAILED(hr)) {
    return hr;
  }

  if (pvarChild->vt == VT_I4 && pvarChild->lVal == CHILDID_SELF) {
    // The document itself has focus.
    // We're handling a call to accFocus on the root accessible,
    // so replace CHILDID_SELF with the document accessible.
    pvarChild->vt = VT_DISPATCH;
    docDisp.forget(&pvarChild->pdispVal);
  }

  return S_OK;
}