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// Copyright 2023 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "ui/accessibility/platform/ax_platform.h"
#include "base/check_op.h"
#include "ui/accessibility/accessibility_features.h"
#include "ui/accessibility/platform/ax_mode_observer.h"
#if BUILDFLAG(IS_WIN)
#include <oleacc.h>
#include <uiautomation.h>
#endif // BUILDFLAG(IS_WIN)
namespace ui {
namespace {
AXPlatform* g_instance = nullptr;
} // namespace
// static
AXPlatform& AXPlatform::GetInstance() {
CHECK_NE(g_instance, nullptr);
DCHECK_CALLED_ON_VALID_THREAD(g_instance->thread_checker_);
return *g_instance;
}
AXPlatform::AXPlatform(Delegate& delegate) : delegate_(delegate) {
DCHECK_EQ(g_instance, nullptr);
g_instance = this;
}
AXPlatform::~AXPlatform() {
DCHECK_EQ(g_instance, this);
DCHECK_CALLED_ON_VALID_THREAD(thread_checker_);
g_instance = nullptr;
}
AXMode AXPlatform::GetMode() {
DCHECK_CALLED_ON_VALID_THREAD(thread_checker_);
return delegate_->GetAccessibilityMode();
}
void AXPlatform::AddModeObserver(AXModeObserver* observer) {
DCHECK_CALLED_ON_VALID_THREAD(thread_checker_);
observers_.AddObserver(observer);
}
void AXPlatform::RemoveModeObserver(AXModeObserver* observer) {
DCHECK_CALLED_ON_VALID_THREAD(thread_checker_);
observers_.RemoveObserver(observer);
}
void AXPlatform::NotifyModeAdded(AXMode mode) {
DCHECK_CALLED_ON_VALID_THREAD(thread_checker_);
observers_.Notify(&AXModeObserver::OnAXModeAdded, mode);
}
void AXPlatform::NotifyAssistiveTechChanged(AssistiveTech assistive_tech) {
DCHECK_CALLED_ON_VALID_THREAD(thread_checker_);
if (active_assistive_tech_ == assistive_tech) {
return;
}
active_assistive_tech_ = assistive_tech;
observers_.Notify(&AXModeObserver::OnAssistiveTechChanged, assistive_tech);
}
bool AXPlatform::IsScreenReaderActive() {
DCHECK_CALLED_ON_VALID_THREAD(thread_checker_);
return IsScreenReader(active_assistive_tech_);
}
bool AXPlatform::IsCaretBrowsingEnabled() {
DCHECK_CALLED_ON_VALID_THREAD(thread_checker_);
return caret_browsing_enabled_;
}
void AXPlatform::SetCaretBrowsingState(bool enabled) {
DCHECK_CALLED_ON_VALID_THREAD(thread_checker_);
caret_browsing_enabled_ = enabled;
}
#if BUILDFLAG(IS_WIN)
const std::string& AXPlatform::GetProductName() const {
DCHECK_CALLED_ON_VALID_THREAD(thread_checker_);
RetrieveProductStringsIfNeeded();
return product_strings_->product_name;
}
const std::string& AXPlatform::GetProductVersion() const {
DCHECK_CALLED_ON_VALID_THREAD(thread_checker_);
RetrieveProductStringsIfNeeded();
return product_strings_->product_version;
}
const std::string& AXPlatform::GetToolkitVersion() const {
DCHECK_CALLED_ON_VALID_THREAD(thread_checker_);
RetrieveProductStringsIfNeeded();
return product_strings_->toolkit_version;
}
void AXPlatform::SetUiaProviderEnabled(bool is_enabled) {
DCHECK_CALLED_ON_VALID_THREAD(thread_checker_);
CHECK_EQ(uia_provider_enablement_, UiaProviderEnablement::kVariations);
uia_provider_enablement_ = is_enabled ? UiaProviderEnablement::kEnabled
: UiaProviderEnablement::kDisabled;
}
void AXPlatform::DisableActiveUiaProvider() {
DCHECK_CALLED_ON_VALID_THREAD(thread_checker_);
if (uia_provider_enablement_ == UiaProviderEnablement::kDisabled) {
// Already disabled.
return;
}
uia_provider_enablement_ = UiaProviderEnablement::kDisabled;
// We must call this *after* we disabled the UIA provider to ensure that we
// don't respond with the same provider to a re-entrant WM_GETOBJECT call. See
// https://learn.microsoft.com/en-us/windows/win32/api/uiautomationcoreapi/nf-uiautomationcoreapi-uiadisconnectallproviders
// for more info.
HRESULT hr = ::UiaDisconnectAllProviders();
DCHECK(SUCCEEDED(hr));
delegate_->OnUiaProviderDisabled();
}
bool AXPlatform::IsUiaProviderEnabled() const {
DCHECK_CALLED_ON_VALID_THREAD(thread_checker_);
return uia_provider_enablement_ == UiaProviderEnablement::kVariations
? base::FeatureList::IsEnabled(features::kUiaProvider)
: (uia_provider_enablement_ == UiaProviderEnablement::kEnabled);
}
void AXPlatform::OnUiaProviderRequested(bool uia_provider_enabled) {
DCHECK_CALLED_ON_VALID_THREAD(thread_checker_);
delegate_->OnUiaProviderRequested(uia_provider_enabled);
}
#endif // BUILDFLAG(IS_WIN)
#if BUILDFLAG(IS_WIN)
void AXPlatform::OnScreenReaderHoneyPotQueried() {
DCHECK_CALLED_ON_VALID_THREAD(thread_checker_);
// We used to trust this as a signal that a screen reader is running, but it's
// been abused. Now only enable accessibility if we detect that the name is
// also used. Do not do the same for location and role, as the Windows Text
// Services Framework (MSTSF) has been known to check the role of each new
// window; see https://crbug.com/416429182.
if (screen_reader_honeypot_queried_) {
return;
}
screen_reader_honeypot_queried_ = true;
if (is_name_used_) {
OnPropertiesUsedInWebContent();
}
}
#endif // BUILDFLAG(IS_WIN)
void AXPlatform::OnMinimalPropertiesUsed(bool is_name_used) {
DCHECK_CALLED_ON_VALID_THREAD(thread_checker_);
delegate_->OnMinimalPropertiesUsed();
#if BUILDFLAG(IS_WIN)
// See OnScreenReaderHoneyPotQueried, above.
if (!is_name_used || is_name_used_) {
return;
}
is_name_used_ = true;
if (screen_reader_honeypot_queried_) {
OnPropertiesUsedInWebContent();
return;
}
#endif
}
void AXPlatform::OnPropertiesUsedInBrowserUI() {
DCHECK_CALLED_ON_VALID_THREAD(thread_checker_);
delegate_->OnPropertiesUsedInBrowserUI();
}
void AXPlatform::OnPropertiesUsedInWebContent() {
DCHECK_CALLED_ON_VALID_THREAD(thread_checker_);
delegate_->OnPropertiesUsedInWebContent();
}
void AXPlatform::OnInlineTextBoxesUsedInWebContent() {
DCHECK_CALLED_ON_VALID_THREAD(thread_checker_);
delegate_->OnInlineTextBoxesUsedInWebContent();
}
void AXPlatform::OnExtendedPropertiesUsedInWebContent() {
DCHECK_CALLED_ON_VALID_THREAD(thread_checker_);
delegate_->OnExtendedPropertiesUsedInWebContent();
}
void AXPlatform::OnHTMLAttributesUsed() {
DCHECK_CALLED_ON_VALID_THREAD(thread_checker_);
delegate_->OnHTMLAttributesUsed();
}
void AXPlatform::OnActionFromAssistiveTech() {
DCHECK_CALLED_ON_VALID_THREAD(thread_checker_);
delegate_->OnActionFromAssistiveTech();
}
void AXPlatform::DetachFromThreadForTesting() {
DETACH_FROM_THREAD(thread_checker_);
}
#if BUILDFLAG(IS_WIN)
void AXPlatform::RetrieveProductStringsIfNeeded() const {
if (!product_strings_) {
product_strings_ = delegate_->GetProductStrings();
}
}
#endif // BUILDFLAG(IS_WIN)
} // namespace ui
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