// Copyright 2012 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#import "chrome/browser/chrome_browser_application_mac.h"
#include <Carbon/Carbon.h> // for <HIToolbox/Events.h>
#include "base/apple/call_with_eh_frame.h"
#include "base/check.h"
#include "base/command_line.h"
#import "base/mac/mac_util.h"
#include "base/observer_list.h"
#include "base/strings/stringprintf.h"
#include "base/strings/sys_string_conversions.h"
#include "base/trace_event/trace_event.h"
#import "chrome/browser/app_controller_mac.h"
#import "chrome/browser/mac/exception_processor.h"
#include "chrome/browser/ui/cocoa/l10n_util.h"
#include "chrome/common/chrome_switches.h"
#include "components/crash/core/common/crash_key.h"
#import "components/crash/core/common/objc_zombie.h"
#include "content/public/browser/browser_accessibility_state.h"
#include "content/public/browser/native_event_processor_mac.h"
#include "content/public/browser/native_event_processor_observer_mac.h"
#include "content/public/common/content_features.h"
#include "ui/base/cocoa/accessibility_focus_overrider.h"
namespace chrome_browser_application_mac {
void RegisterBrowserCrApp() {
[BrowserCrApplication sharedApplication];
// If there was an invocation to NSApp prior to this method, then the NSApp
// will not be a BrowserCrApplication, but will instead be an NSApplication.
// This is undesirable and we must enforce that this doesn't happen.
CHECK([NSApp isKindOfClass:[BrowserCrApplication class]]);
}
void InitializeHeadlessMode() {
// In headless mode the browser window exists but is always hidden, so there
// is no point in showing dock icon and menu bar.
NSApp.activationPolicy = NSApplicationActivationPolicyAccessory;
}
void Terminate() {
[NSApp terminate:nil];
}
void CancelTerminate() {
[NSApp cancelTerminate:nil];
}
// A convenience function that activates `mode` if not already active in
// `state`.
void AddAccessibilityModeFlagsIfAbsent(
content::BrowserAccessibilityState* state,
ui::AXMode mode) {
if (!state->GetAccessibilityMode().has_mode(mode.flags())) {
state->AddAccessibilityModeFlags(mode);
}
}
} // namespace chrome_browser_application_mac
namespace {
// Calling -[NSEvent description] is rather slow to build up the event
// description. The description is stored in a crash key to aid debugging, so
// this helper function constructs a shorter, but still useful, description.
// See <https://crbug.com/770405>.
std::string DescriptionForNSEvent(NSEvent* event) {
std::string desc = base::StringPrintf(
"NSEvent type=%ld modifierFlags=0x%lx locationInWindow=(%g,%g)",
event.type, event.modifierFlags, event.locationInWindow.x,
event.locationInWindow.y);
switch (event.type) {
case NSEventTypeKeyDown:
case NSEventTypeKeyUp: {
// Some NSEvents return a string with NUL in event.characters, see
// <https://crbug.com/826908>. To make matters worse, in rare cases,
// NSEvent.characters or NSEvent.charactersIgnoringModifiers can throw an
// NSException complaining that "TSMProcessRawKeyCode failed". Since we're
// trying to gather a crash key here, if that exception happens, just
// remark that it happened and continue rather than crashing the browser.
std::string characters, unmodified_characters;
@try {
characters = base::SysNSStringToUTF8([event.characters
stringByReplacingOccurrencesOfString:@"\0"
withString:@"\\x00"]);
unmodified_characters =
base::SysNSStringToUTF8([event.charactersIgnoringModifiers
stringByReplacingOccurrencesOfString:@"\0"
withString:@"\\x00"]);
} @catch (id exception) {
characters = "(exception)";
unmodified_characters = "(exception)";
}
desc += base::StringPrintf(
" keyCode=0x%d ARepeat=%d characters='%s' unmodifiedCharacters='%s'",
event.keyCode, event.ARepeat, characters.c_str(),
unmodified_characters.c_str());
break;
}
case NSEventTypeLeftMouseDown:
case NSEventTypeLeftMouseDragged:
case NSEventTypeLeftMouseUp:
case NSEventTypeOtherMouseDown:
case NSEventTypeOtherMouseDragged:
case NSEventTypeOtherMouseUp:
case NSEventTypeRightMouseDown:
case NSEventTypeRightMouseDragged:
case NSEventTypeRightMouseUp:
desc += base::StringPrintf(" buttonNumber=%ld clickCount=%ld",
event.buttonNumber, event.clickCount);
break;
case NSEventTypeAppKitDefined:
case NSEventTypeSystemDefined:
case NSEventTypeApplicationDefined:
case NSEventTypePeriodic:
desc += base::StringPrintf(" subtype=%d data1=%ld data2=%ld",
event.subtype, event.data1, event.data2);
break;
default:
break;
}
return desc;
}
} // namespace
@interface BrowserCrApplication () <NativeEventProcessor> {
// A counter for enhanced user interface enable (+1) and disable (-1)
// requests.
int _AXEnhancedUserInterfaceRequests;
BOOL _voiceOverEnabled;
BOOL _sonomaAccessibilityRefinementsAreActive;
}
// Enables/disables screen reader support on changes to VoiceOver status.
- (void)voiceOverStateChanged:(BOOL)voiceOverEnabled;
@end
@implementation BrowserCrApplication {
base::ObserverList<content::NativeEventProcessorObserver>::Unchecked
_observers;
BOOL _handlingSendEvent;
}
+ (void)initialize {
if (self != [BrowserCrApplication class]) {
return;
}
InstallObjcExceptionPreprocessor();
cocoa_l10n_util::ApplyForcedRTL();
}
// Initialize NSApplication using the custom subclass. Check whether NSApp
// was already initialized using another class, because that would break
// some things.
+ (NSApplication*)sharedApplication {
NSApplication* app = [super sharedApplication];
// +sharedApplication initializes the global NSApp, so if a specific
// NSApplication subclass is requested, require that to be the one
// delivered. The practical effect is to require a consistent NSApp
// across the executable.
CHECK([NSApp isKindOfClass:self])
<< "NSApp must be of type " << [[self className] UTF8String]
<< ", not " << [[NSApp className] UTF8String];
// If the message loop was initialized before NSApp is setup, the
// message pump will be setup incorrectly. Failing this implies
// that RegisterBrowserCrApp() should be called earlier.
CHECK(base::message_pump_apple::UsingCrApp())
<< "message_pump_apple::Create() is using the wrong pump implementation"
<< " for " << [[self className] UTF8String];
return app;
}
- (void)finishLaunching {
[super finishLaunching];
// The accessibility feature, enabled from Finch, should already be
// restricted to macOS 14, but we'll make an additional check here in the
// code.
_sonomaAccessibilityRefinementsAreActive =
base::mac::MacOSVersion() >= 14'00'00 &&
base::FeatureList::IsEnabled(
features::kSonomaAccessibilityActivationRefinements);
}
- (void)observeValueForKeyPath:(NSString*)keyPath
ofObject:(id)object
change:(NSDictionary*)change
context:(void*)context {
// KVO of the system's VoiceOver state gets set up during initialization of
// BrowserAccessibilityStateImplMac. The context is the browser's
// global accessibility object, which we must check to ensure we're acting
// on a notification we set up (vs. NSApplication, say).
if (_sonomaAccessibilityRefinementsAreActive &&
[keyPath isEqualToString:@"voiceOverEnabled"] &&
context == content::BrowserAccessibilityState::GetInstance()) {
NSNumber* newValueNumber = [change objectForKey:NSKeyValueChangeNewKey];
// In the if statement below, we check newValueNumber's class before
// accessing it to guard against crashes should the return type suddenly
// change in the future. We DCHECK here to flag any such change.
DCHECK([newValueNumber isKindOfClass:[NSNumber class]]);
if ([newValueNumber isKindOfClass:[NSNumber class]]) {
[self voiceOverStateChanged:[newValueNumber boolValue]];
}
return;
}
[super observeValueForKeyPath:keyPath
ofObject:object
change:change
context:context];
}
// AppKit menu customization overriding
- (void)_customizeFileMenuIfNeeded {
// Whenever the main menu is set or modified, AppKit modifies it before using
// it. AppKit calls -[NSApplication _customizeMainMenu], which calls out to a
// number of customization methods, including -[NSApplication
// _customizeFileMenuIfNeeded].
//
// -_customizeFileMenuIfNeeded does three things:
// 1. it adds the "Close All" menu item as an alternate for "Close Window",
// 2. for new-style document apps, it turns "Save" and "Save As..." into
// "Save..." and "Duplicate" respectively,
// 3. depending on the "Close windows when quitting an application" system
// setting, it adds either "Quit and Keep Windows" or "Quit and Close All
// Windows" as an alternate for "Quit Chromium".
//
// While #1 is a nice-to-have, and #2 is irrelevant because Chromium isn't a
// new-style document app, #3 is a problem. Chromium has its own session
// management, and the menu item alternates that AppKit adds are making
// promises that Chromium can't fulfill.
//
// Therefore, override this method to prevent AppKit from doing these menu
// shenanigans. For #1, "Close All" is explicitly added to the File menu in
// main_menu_builder.mm, and there is nothing lost by preventing the other
// two.
return;
}
////////////////////////////////////////////////////////////////////////////////
// HISTORICAL COMMENT (by viettrungluu, from
// http://codereview.chromium.org/1520006 with mild editing):
//
// A quick summary of the state of things (before the changes to shutdown):
//
// Currently, we are totally hosed (put in a bad state in which Cmd-W does the
// wrong thing, and which will probably eventually lead to a crash) if we begin
// quitting but termination is aborted for some reason.
//
// I currently know of two ways in which termination can be aborted:
// (1) Common case: a window has an onbeforeunload handler which pops up a
// "leave web page" dialog, and the user answers "no, don't leave".
// (2) Uncommon case: popups are enabled (in Content Settings, i.e., the popup
// blocker is disabled), and some nasty web page pops up a new window on
// closure.
//
// I don't know of other ways in which termination can be aborted, but they may
// exist (or may be added in the future, for that matter).
//
// My CL [see above] does the following:
// a. Should prevent being put in a bad state (which breaks Cmd-W and leads to
// crash) under all circumstances.
// b. Should completely handle (1) properly.
// c. Doesn't (yet) handle (2) properly and puts it in a weird state (but not
// that bad).
// d. Any other ways of aborting termination would put it in that weird state.
//
// c. can be fixed by having the global flag reset on browser creation or
// similar (and doing so might also fix some possible d.'s as well). I haven't
// done this yet since I haven't thought about it carefully and since it's a
// corner case.
//
// The weird state: a state in which closing the last window quits the browser.
// This might be a bit annoying, but it's not dangerous in any way.
////////////////////////////////////////////////////////////////////////////////
// |-terminate:| is the entry point for orderly "quit" operations in Cocoa. This
// includes the application menu's quit menu item and keyboard equivalent, the
// application's dock icon menu's quit menu item, "quit" (not "force quit") in
// the Activity Monitor, and quits triggered by user logout and system restart
// and shutdown.
//
// The default |-terminate:| implementation ends the process by calling exit(),
// and thus never leaves the main run loop. This is unsuitable for Chrome since
// Chrome depends on leaving the main run loop to perform an orderly shutdown.
// We support the normal |-terminate:| interface by overriding the default
// implementation. Our implementation, which is very specific to the needs of
// Chrome, works by asking the application delegate to terminate using its
// |-tryToTerminateApplication:| method.
//
// |-tryToTerminateApplication:| differs from the standard
// |-applicationShouldTerminate:| in that no special event loop is run in the
// case that immediate termination is not possible (e.g., if dialog boxes
// allowing the user to cancel have to be shown). Instead, this method sets a
// flag and tries to close all browsers. This flag causes the closure of the
// final browser window to begin actual tear-down of the application.
// Termination is cancelled by resetting this flag. The standard
// |-applicationShouldTerminate:| is not supported, and code paths leading to it
// must be redirected.
//
// When the last browser has been destroyed, the BrowserList calls
// chrome::OnAppExiting(), which is the point of no return. That will cause
// the NSApplicationWillTerminateNotification to be posted, which ends the
// NSApplication event loop, so final post- MessageLoop::Run() work is done
// before exiting.
- (void)terminate:(id)sender {
[AppController.sharedController tryToTerminateApplication:self];
// Return, don't exit. The application is responsible for exiting on its own.
}
- (void)cancelTerminate:(id)sender {
[AppController.sharedController stopTryingToTerminateApplication:self];
}
- (NSEvent*)nextEventMatchingMask:(NSEventMask)mask
untilDate:(NSDate*)expiration
inMode:(NSString*)mode
dequeue:(BOOL)dequeue {
__block NSEvent* event = nil;
base::apple::CallWithEHFrame(^{
event = [super nextEventMatchingMask:mask
untilDate:expiration
inMode:mode
dequeue:dequeue];
});
return event;
}
- (BOOL)sendAction:(SEL)anAction to:(id)aTarget from:(id)sender {
// The Dock menu contains an automagic section where you can select
// amongst open windows. If a window is closed via JavaScript while
// the menu is up, the menu item for that window continues to exist.
// When a window is selected this method is called with the
// now-freed window as |aTarget|. Short-circuit the call if
// |aTarget| is not a valid window.
if (anAction == @selector(_selectWindow:)) {
// Not using -[NSArray containsObject:] because |aTarget| may be a
// freed object.
BOOL found = NO;
for (NSWindow* window in [self windows]) {
if (window == aTarget) {
found = YES;
break;
}
}
if (!found) {
return NO;
}
}
// When a Cocoa control is wired to a freed object, we get crashers
// in the call to |super| with no useful information in the
// backtrace. Attempt to add some useful information.
// If the action is something generic like -commandDispatch:, then
// the tag is essential.
NSInteger tag = 0;
if ([sender isKindOfClass:[NSControl class]]) {
tag = [sender tag];
if (tag == 0 || tag == -1) {
tag = [sender selectedTag];
}
} else if ([sender isKindOfClass:[NSMenuItem class]]) {
tag = [sender tag];
}
NSString* actionString = NSStringFromSelector(anAction);
std::string value = base::StringPrintf("%s tag %ld sending %s to %p",
[[sender className] UTF8String],
static_cast<long>(tag),
[actionString UTF8String],
aTarget);
static crash_reporter::CrashKeyString<256> sendActionKey("sendaction");
crash_reporter::ScopedCrashKeyString scopedKey(&sendActionKey, value);
__block BOOL rv;
base::apple::CallWithEHFrame(^{
rv = [super sendAction:anAction to:aTarget from:sender];
});
return rv;
}
- (BOOL)isHandlingSendEvent {
return _handlingSendEvent;
}
- (void)setHandlingSendEvent:(BOOL)handlingSendEvent {
_handlingSendEvent = handlingSendEvent;
}
- (void)sendEvent:(NSEvent*)event {
TRACE_EVENT0("toplevel", "BrowserCrApplication::sendEvent");
// TODO(bokan): Tracing added temporarily to diagnose crbug.com/1039833.
TRACE_EVENT_INSTANT1("toplevel", "KeyWindow", TRACE_EVENT_SCOPE_THREAD,
"KeyWin", [[NSApp keyWindow] windowNumber]);
static crash_reporter::CrashKeyString<256> nseventKey("nsevent");
crash_reporter::ScopedCrashKeyString scopedKey(&nseventKey,
DescriptionForNSEvent(event));
base::apple::CallWithEHFrame(^{
static const bool kKioskMode =
base::CommandLine::ForCurrentProcess()->HasSwitch(switches::kKioskMode);
if (kKioskMode) {
// In kiosk mode, we want to prevent context menus from appearing,
// so simply discard menu-generating events instead of passing them
// along.
BOOL couldTriggerContextMenu =
event.type == NSEventTypeRightMouseDown ||
(event.type == NSEventTypeLeftMouseDown &&
(event.modifierFlags & NSEventModifierFlagControl));
if (couldTriggerContextMenu)
return;
}
base::mac::ScopedSendingEvent sendingEventScoper;
content::ScopedNotifyNativeEventProcessorObserver scopedObserverNotifier(
&self->_observers, event);
// Mac Eisu and Kana keydown events are by default swallowed by sendEvent
// and sent directly to IME, which prevents ui keydown events from firing.
// These events need to be sent to [NSApp keyWindow] for handling.
if (event.type == NSEventTypeKeyDown &&
(event.keyCode == kVK_JIS_Eisu || event.keyCode == kVK_JIS_Kana)) {
[NSApp.keyWindow sendEvent:event];
} else {
[super sendEvent:event];
}
});
}
// Accessibility Support
- (void)enableScreenReaderCompleteMode:(BOOL)enable {
content::BrowserAccessibilityState* accessibility_state =
content::BrowserAccessibilityState::GetInstance();
if (enable) {
accessibility_state->OnScreenReaderDetected();
} else {
accessibility_state->OnScreenReaderStopped();
}
}
// We need to call enableScreenReaderCompleteMode:YES from performSelector:...
// but there's no way to supply a BOOL as a parameter, so we have this
// explicit enable... helper method.
- (void)enableScreenReaderCompleteMode {
_AXEnhancedUserInterfaceRequests = 0;
[self enableScreenReaderCompleteMode:YES];
}
- (void)voiceOverStateChanged:(BOOL)voiceOverEnabled {
_voiceOverEnabled = voiceOverEnabled;
[self enableScreenReaderCompleteMode:voiceOverEnabled];
}
- (BOOL)voiceOverStateForTesting {
return _voiceOverEnabled;
}
// Enables or disables screen reader support for non-VoiceOver assistive
// technology (AT), possibly after a delay.
//
// Now that we directly monitor VoiceOver status, we no longer watch for
// changes to AXEnhancedUserInterface for that signal from VO. However, other
// AT can set a value for AXEnhancedUserInterface, so we can't ignore it.
// Unfortunately, as of macOS Sonoma, we sometimes see spurious changes to
// AXEnhancedUserInterface (quick on and off). We debounce by waiting for these
// changes to settle down before updating the screen reader state.
- (void)enableScreenReaderCompleteModeAfterDelay:(BOOL)enable {
// If VoiceOver is already explicitly enabled, ignore requests from other AT.
if (_voiceOverEnabled) {
return;
}
// If this is a request to disable screen reader support, and we haven't seen
// a corresponding enable request, go ahead and disable.
if (!enable && _AXEnhancedUserInterfaceRequests == 0) {
[self enableScreenReaderCompleteMode:NO];
return;
}
// Use a counter to track requests for changes to the screen reader state.
if (enable) {
_AXEnhancedUserInterfaceRequests++;
} else {
_AXEnhancedUserInterfaceRequests--;
}
DCHECK(_AXEnhancedUserInterfaceRequests >= 0);
// _AXEnhancedUserInterfaceRequests > 0 means we want to enable screen
// reader support, but we'll delay that action until there are no more state
// change requests within a two-second window. Cancel any pending
// performSelector:..., and schedule a new one to restart the countdown.
[NSObject cancelPreviousPerformRequestsWithTarget:self
selector:@selector
(enableScreenReaderCompleteMode)
object:nil];
if (_AXEnhancedUserInterfaceRequests > 0) {
const float kTwoSecondDelay = 2.0;
[self performSelector:@selector(enableScreenReaderCompleteMode)
withObject:nil
afterDelay:kTwoSecondDelay];
}
}
- (void)accessibilitySetValue:(id)value forAttribute:(NSString*)attribute {
// This is an undocumented attribute that's set when VoiceOver is turned
// on/off.
if ([attribute isEqualToString:@"AXEnhancedUserInterface"]) {
if (_sonomaAccessibilityRefinementsAreActive) {
// We no longer rely on this signal for VoiceOver state changes, but we
// pay attention to it in case other applications use it to request
// accessibility activation.
[self enableScreenReaderCompleteModeAfterDelay:[value boolValue]];
} else {
content::BrowserAccessibilityState* accessibility_state =
content::BrowserAccessibilityState::GetInstance();
if ([value boolValue]) {
accessibility_state->OnScreenReaderDetected();
} else {
accessibility_state->OnScreenReaderStopped();
}
}
}
return [super accessibilitySetValue:value forAttribute:attribute];
}
- (id)accessibilityFocusedUIElement {
if (id forced_focus = ui::AccessibilityFocusOverrider::GetFocusedUIElement())
return forced_focus;
return [super accessibilityFocusedUIElement];
}
- (NSAccessibilityRole)accessibilityRole {
// For non-VoiceOver assistive technology (AT), such as Voice Control, Apple
// recommends turning on a11y when an AT accesses the 'accessibilityRole'
// property. This function is accessed frequently, so we only change the
// accessibility state when accessibility is already disabled.
content::BrowserAccessibilityState* accessibility_state =
content::BrowserAccessibilityState::GetInstance();
if (_sonomaAccessibilityRefinementsAreActive) {
if (!_voiceOverEnabled) {
chrome_browser_application_mac::AddAccessibilityModeFlagsIfAbsent(
accessibility_state, ui::AXMode::kNativeAPIs);
}
} else {
if (!accessibility_state->GetAccessibilityMode().has_mode(
ui::kAXModeBasic.flags())) {
accessibility_state->AddAccessibilityModeFlags(ui::kAXModeBasic);
}
}
return [super accessibilityRole];
}
- (void)addNativeEventProcessorObserver:
(content::NativeEventProcessorObserver*)observer {
_observers.AddObserver(observer);
}
- (void)removeNativeEventProcessorObserver:
(content::NativeEventProcessorObserver*)observer {
_observers.RemoveObserver(observer);
}
@end
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