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// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "content/browser/accessibility/accessibility_event_recorder.h"
#include <oleacc.h>
#include <string>
#include "base/strings/string_number_conversions.h"
#include "base/strings/string_util.h"
#include "base/strings/stringprintf.h"
#include "base/strings/utf_string_conversions.h"
#include "base/win/scoped_bstr.h"
#include "base/win/scoped_comptr.h"
#include "base/win/scoped_variant.h"
#include "content/browser/accessibility/accessibility_tree_formatter_utils_win.h"
#include "content/browser/accessibility/browser_accessibility_manager.h"
#include "content/browser/accessibility/browser_accessibility_win.h"
#include "third_party/iaccessible2/ia2_api_all.h"
#include "ui/base/win/atl_module.h"
namespace content {
namespace {
std::string RoleVariantToString(const base::win::ScopedVariant& role) {
if (role.type() == VT_I4) {
return base::UTF16ToUTF8(IAccessibleRoleToString(V_I4(&role)));
} else if (role.type() == VT_BSTR) {
return base::UTF16ToUTF8(
base::string16(V_BSTR(&role), SysStringLen(V_BSTR(&role))));
}
return std::string();
}
HRESULT QueryIAccessible2(IAccessible* accessible, IAccessible2** accessible2) {
base::win::ScopedComPtr<IServiceProvider> service_provider;
HRESULT hr = accessible->QueryInterface(service_provider.Receive());
return SUCCEEDED(hr) ?
service_provider->QueryService(IID_IAccessible2, accessible2) : hr;
}
std::string BstrToUTF8(BSTR bstr) {
base::string16 str16(bstr, SysStringLen(bstr));
return base::UTF16ToUTF8(str16);
}
std::string AccessibilityEventToStringUTF8(int32 event_id) {
return base::UTF16ToUTF8(AccessibilityEventToString(event_id));
}
} // namespace
class AccessibilityEventRecorderWin : public AccessibilityEventRecorder {
public:
explicit AccessibilityEventRecorderWin(BrowserAccessibilityManager* manager);
virtual ~AccessibilityEventRecorderWin();
// Callback registered by SetWinEventHook. Just calls OnWinEventHook.
static void CALLBACK WinEventHookThunk(
HWINEVENTHOOK handle,
DWORD event,
HWND hwnd,
LONG obj_id,
LONG child_id,
DWORD event_thread,
DWORD event_time);
private:
// Called by the thunk registered by SetWinEventHook. Retrives accessibility
// info about the node the event was fired on and appends a string to
// the event log.
void OnWinEventHook(HWINEVENTHOOK handle,
DWORD event,
HWND hwnd,
LONG obj_id,
LONG child_id,
DWORD event_thread,
DWORD event_time);
HWINEVENTHOOK win_event_hook_handle_;
static AccessibilityEventRecorderWin* instance_;
};
// static
AccessibilityEventRecorderWin*
AccessibilityEventRecorderWin::instance_ = nullptr;
// static
AccessibilityEventRecorder* AccessibilityEventRecorder::Create(
BrowserAccessibilityManager* manager) {
return new AccessibilityEventRecorderWin(manager);
}
// static
void CALLBACK AccessibilityEventRecorderWin::WinEventHookThunk(
HWINEVENTHOOK handle,
DWORD event,
HWND hwnd,
LONG obj_id,
LONG child_id,
DWORD event_thread,
DWORD event_time) {
if (instance_) {
instance_->OnWinEventHook(handle, event, hwnd, obj_id, child_id,
event_thread, event_time);
}
}
AccessibilityEventRecorderWin::AccessibilityEventRecorderWin(
BrowserAccessibilityManager* manager)
: AccessibilityEventRecorder(manager) {
CHECK(!instance_) << "There can be only one instance of"
<< " WinAccessibilityEventMonitor at a time.";
instance_ = this;
win_event_hook_handle_ = SetWinEventHook(
EVENT_MIN,
EVENT_MAX,
GetModuleHandle(NULL),
&AccessibilityEventRecorderWin::WinEventHookThunk,
GetCurrentProcessId(),
0, // Hook all threads
WINEVENT_INCONTEXT);
}
AccessibilityEventRecorderWin::~AccessibilityEventRecorderWin() {
UnhookWinEvent(win_event_hook_handle_);
instance_ = NULL;
}
void AccessibilityEventRecorderWin::OnWinEventHook(
HWINEVENTHOOK handle,
DWORD event,
HWND hwnd,
LONG obj_id,
LONG child_id,
DWORD event_thread,
DWORD event_time) {
base::win::ScopedComPtr<IAccessible> browser_accessible;
HRESULT hr = AccessibleObjectFromWindow(
hwnd,
obj_id,
IID_IAccessible,
reinterpret_cast<void**>(browser_accessible.Receive()));
if (!SUCCEEDED(hr)) {
// Note: our event hook will pick up some superfluous events we
// don't care about, so it's safe to just ignore these failures.
// Same below for other HRESULT checks.
VLOG(1) << "Ignoring result " << hr << " from AccessibleObjectFromWindow";
return;
}
base::win::ScopedVariant childid_variant(child_id);
base::win::ScopedComPtr<IDispatch> dispatch;
hr = browser_accessible->get_accChild(childid_variant, dispatch.Receive());
if (!SUCCEEDED(hr) || !dispatch) {
VLOG(1) << "Ignoring result " << hr << " and result " << dispatch
<< " from get_accChild";
return;
}
base::win::ScopedComPtr<IAccessible> iaccessible;
hr = dispatch.QueryInterface(iaccessible.Receive());
if (!SUCCEEDED(hr)) {
VLOG(1) << "Ignoring result " << hr << " from QueryInterface";
return;
}
base::win::ScopedVariant childid_self(CHILDID_SELF);
base::win::ScopedVariant role;
iaccessible->get_accRole(childid_self, role.Receive());
base::win::ScopedBstr name_bstr;
iaccessible->get_accName(childid_self, name_bstr.Receive());
base::win::ScopedBstr value_bstr;
iaccessible->get_accValue(childid_self, value_bstr.Receive());
std::string log = base::StringPrintf(
"%s on role=%s",
AccessibilityEventToStringUTF8(event).c_str(),
RoleVariantToString(role).c_str());
if (name_bstr.Length() > 0)
log += base::StringPrintf(" name=\"%s\"", BstrToUTF8(name_bstr).c_str());
if (value_bstr.Length() > 0)
log += base::StringPrintf(" value=\"%s\"", BstrToUTF8(value_bstr).c_str());
event_logs_.push_back(log);
}
} // namespace content
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