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// Copyright (c) 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 <string>
#import <Cocoa/Cocoa.h>
#include "base/mac/foundation_util.h"
#include "base/strings/string_number_conversions.h"
#include "base/strings/string_util.h"
#include "base/strings/stringprintf.h"
#include "base/strings/sys_string_conversions.h"
#include "base/strings/utf_string_conversions.h"
#include "content/browser/accessibility/browser_accessibility_manager.h"
namespace content {
// Implementation of AccessibilityEventRecorder that uses AXObserver to
// watch for NSAccessibility events.
class AccessibilityEventRecorderMac : public AccessibilityEventRecorder {
public:
explicit AccessibilityEventRecorderMac(BrowserAccessibilityManager* manager);
~AccessibilityEventRecorderMac() override;
// Callback executed every time we receive an event notification.
void EventReceived(AXUIElementRef element, CFStringRef notification);
private:
// Add one notification to the list of notifications monitored by our
// observer.
void AddNotification(NSString* notification);
// Convenience function to get the value of an AX attribute from
// an AXUIElementRef as a string.
std::string GetAXAttributeValue(
AXUIElementRef element, NSString* attribute_name);
// The AXUIElement for the Chrome application.
AXUIElementRef application_;
// The AXObserver we use to monitor AX notifications.
AXObserverRef observer_ref_;
};
// Callback function registered using AXObserverCreate.
static void EventReceivedThunk(
AXObserverRef observer_ref,
AXUIElementRef element,
CFStringRef notification,
void *refcon) {
AccessibilityEventRecorderMac* this_ptr =
static_cast<AccessibilityEventRecorderMac*>(refcon);
this_ptr->EventReceived(element, notification);
}
// static
AccessibilityEventRecorder* AccessibilityEventRecorder::Create(
BrowserAccessibilityManager* manager) {
return new AccessibilityEventRecorderMac(manager);
}
AccessibilityEventRecorderMac::AccessibilityEventRecorderMac(
BrowserAccessibilityManager* manager)
: AccessibilityEventRecorder(manager),
observer_ref_(0) {
// Get Chrome's process id.
int pid = [[NSProcessInfo processInfo] processIdentifier];
if (kAXErrorSuccess != AXObserverCreate(
pid, EventReceivedThunk, &observer_ref_)) {
LOG(FATAL) << "Failed to create AXObserverRef";
}
// Get an AXUIElement for the Chrome application.
application_ = AXUIElementCreateApplication(pid);
if (!application_)
LOG(FATAL) << "Failed to create AXUIElement for application.";
// Add the notifications we care about to the observer.
AddNotification(NSAccessibilityFocusedUIElementChangedNotification);
AddNotification(NSAccessibilityRowCountChangedNotification);
AddNotification(NSAccessibilitySelectedChildrenChangedNotification);
AddNotification(NSAccessibilitySelectedRowsChangedNotification);
AddNotification(NSAccessibilitySelectedTextChangedNotification);
AddNotification(NSAccessibilityValueChangedNotification);
AddNotification(@"AXLayoutComplete");
AddNotification(@"AXLiveRegionChanged");
AddNotification(@"AXLoadComplete");
AddNotification(@"AXRowCollapsed");
AddNotification(@"AXRowExpanded");
// Add the observer to the current message loop.
CFRunLoopAddSource(
[[NSRunLoop currentRunLoop] getCFRunLoop],
AXObserverGetRunLoopSource(observer_ref_),
kCFRunLoopDefaultMode);
}
AccessibilityEventRecorderMac::~AccessibilityEventRecorderMac() {
CFRelease(application_);
CFRelease(observer_ref_);
}
void AccessibilityEventRecorderMac::AddNotification(NSString* notification) {
AXObserverAddNotification(observer_ref_,
application_,
static_cast<CFStringRef>(notification),
this);
}
std::string AccessibilityEventRecorderMac::GetAXAttributeValue(
AXUIElementRef element, NSString* attribute_name) {
CFTypeRef value;
AXError err = AXUIElementCopyAttributeValue(
element, static_cast<CFStringRef>(attribute_name), &value);
if (err != kAXErrorSuccess)
return std::string();
return base::SysNSStringToUTF8(
base::mac::CFToNSCast(static_cast<CFStringRef>(value)));
}
void AccessibilityEventRecorderMac::EventReceived(
AXUIElementRef element,
CFStringRef notification) {
std::string notification_str = base::SysNSStringToUTF8(
base::mac::CFToNSCast(notification));
std::string role = GetAXAttributeValue(element, NSAccessibilityRoleAttribute);
if (role.empty())
return;
std::string log = base::StringPrintf("%s on %s",
notification_str.c_str(), role.c_str());
std::string title = GetAXAttributeValue(element,
NSAccessibilityTitleAttribute);
if (!title.empty())
log += base::StringPrintf(" AXTitle=\"%s\"", title.c_str());
std::string description = GetAXAttributeValue(element,
NSAccessibilityDescriptionAttribute);
if (!description.empty())
log += base::StringPrintf(" AXDescription=\"%s\"", description.c_str());
std::string value = GetAXAttributeValue(element,
NSAccessibilityValueAttribute);
if (!value.empty())
log += base::StringPrintf(" AXValue=\"%s\"", value.c_str());
event_logs_.push_back(log);
}
} // namespace content
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