Re: [PATCH v7 20/22] ui/cocoa: capture all keys and combos when mouse is grabbed

[Will Cohen <wwcohen@gmail.com>]

[-- Attachment #1: Type: text/plain, Size: 7156 bytes --]

On Sun, Mar 6, 2022 at 6:19 PM Philippe Mathieu-Daudé <
philippe.mathieu.daude@gmail.com> wrote:

> From: Gustavo Noronha Silva <gustavo@noronha.dev.br>
>
> Applications such as Gnome may use Alt-Tab and Super-Tab for different
> purposes, some use Ctrl-arrows so we want to allow qemu to handle
> everything when it captures the mouse/keyboard.
>
> However, Mac OS handles some combos like Command-Tab and Ctrl-arrows
> at an earlier part of the event handling chain, not letting qemu see it.
>
> We add a global Event Tap that allows qemu to see all events when the
> mouse is grabbed. Note that this requires additional permissions.
>
> See:
>
>
> https://developer.apple.com/documentation/coregraphics/1454426-cgeventtapcreate?language=objc#discussion
> https://support.apple.com/en-in/guide/mac-help/mh32356/mac
>
> Acked-by: Markus Armbruster <armbru@redhat.com>
> Signed-off-by: Gustavo Noronha Silva <gustavo@noronha.dev.br>
> Message-Id: <20210713213200.2547-2-gustavo@noronha.dev.br>
> Signed-off-by: Akihiko Odaki <akihiko.odaki@gmail.com>
> Message-Id: <20220306121119.45631-2-akihiko.odaki@gmail.com>
> Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
> ---
>  qapi/ui.json    |  8 +++++-
>  qemu-options.hx |  3 +++
>  ui/cocoa.m      | 65 ++++++++++++++++++++++++++++++++++++++++++++++++-
>  3 files changed, 74 insertions(+), 2 deletions(-)
>
> diff --git a/qapi/ui.json b/qapi/ui.json
> index 4dea35a819..1d60d5fc78 100644
> --- a/qapi/ui.json
> +++ b/qapi/ui.json
> @@ -1270,11 +1270,17 @@
>  #                    host without sending this key to the guest when
>  #                    "off". Defaults to "on"
>  #
> +# @full-grab: Capture all key presses, including system combos. This
> +#             requires accessibility permissions, since it performs
> +#             a global grab on key events. (default: off)
> +#             See
> https://support.apple.com/en-in/guide/mac-help/mh32356/mac
> +#
>  # Since: 7.0
>  ##
>  { 'struct': 'DisplayCocoa',
>    'data': {
> -      '*left-command-key': 'bool'
> +      '*left-command-key': 'bool',
> +      '*full-grab': 'bool'
>    } }
>
>  ##
> diff --git a/qemu-options.hx b/qemu-options.hx
> index ffaeab61ed..2e6d54db4f 100644
> --- a/qemu-options.hx
> +++ b/qemu-options.hx
> @@ -1916,6 +1916,9 @@ DEF("display", HAS_ARG, QEMU_OPTION_display,
>  #if defined(CONFIG_CURSES)
>      "-display curses[,charset=<encoding>]\n"
>  #endif
> +#if defined(CONFIG_COCOA)
> +    "-display cocoa[,full_grab=on|off]\n"
> +#endif
>  #if defined(CONFIG_OPENGL)
>      "-display egl-headless[,rendernode=<file>]\n"
>  #endif
> diff --git a/ui/cocoa.m b/ui/cocoa.m
> index 31f0846c30..ca1cab1ae6 100644
> --- a/ui/cocoa.m
> +++ b/ui/cocoa.m
> @@ -309,11 +309,13 @@ static void handleAnyDeviceErrors(Error * err)
>      BOOL isMouseGrabbed;
>      BOOL isFullscreen;
>      BOOL isAbsoluteEnabled;
> +    CFMachPortRef eventsTap;
>  }
>  - (void) switchSurface:(pixman_image_t *)image;
>  - (void) grabMouse;
>  - (void) ungrabMouse;
>  - (void) toggleFullScreen:(id)sender;
> +- (void) setFullGrab:(id)sender;
>  - (void) handleMonitorInput:(NSEvent *)event;
>  - (bool) handleEvent:(NSEvent *)event;
>  - (bool) handleEventLocked:(NSEvent *)event;
> @@ -336,6 +338,19 @@ static void handleAnyDeviceErrors(Error * err)
>
>  QemuCocoaView *cocoaView;
>
> +static CGEventRef handleTapEvent(CGEventTapProxy proxy, CGEventType type,
> CGEventRef cgEvent, void *userInfo)
> +{
> +    QemuCocoaView *cocoaView = userInfo;
> +    NSEvent *event = [NSEvent eventWithCGEvent:cgEvent];
> +    if ([cocoaView isMouseGrabbed] && [cocoaView handleEvent:event]) {
> +        COCOA_DEBUG("Global events tap: qemu handled the event,
> capturing!\n");
> +        return NULL;
> +    }
> +    COCOA_DEBUG("Global events tap: qemu did not handle the event,
> letting it through...\n");
> +
> +    return cgEvent;
> +}
> +
>  @implementation QemuCocoaView
>  - (id)initWithFrame:(NSRect)frameRect
>  {
> @@ -361,6 +376,11 @@ QemuCocoaView *cocoaView;
>      }
>
>      qkbd_state_free(kbd);
> +
> +    if (eventsTap) {
> +        CFRelease(eventsTap);
> +    }
> +
>      [super dealloc];
>  }
>
> @@ -655,6 +675,36 @@ QemuCocoaView *cocoaView;
>      }
>  }
>
> +- (void) setFullGrab:(id)sender
> +{
> +    COCOA_DEBUG("QemuCocoaView: setFullGrab\n");
> +
> +    CGEventMask mask = CGEventMaskBit(kCGEventKeyDown) |
> CGEventMaskBit(kCGEventKeyUp) | CGEventMaskBit(kCGEventFlagsChanged);
> +    eventsTap = CGEventTapCreate(kCGHIDEventTap, kCGHeadInsertEventTap,
> kCGEventTapOptionDefault,
> +                                 mask, handleTapEvent, self);
> +    if (!eventsTap) {
> +        warn_report("Could not create event tap, system key combos will
> not be captured.\n");
> +        return;
> +    } else {
> +        COCOA_DEBUG("Global events tap created! Will capture system key
> combos.\n");
> +    }
> +
> +    CFRunLoopRef runLoop = CFRunLoopGetCurrent();
> +    if (!runLoop) {
> +        warn_report("Could not obtain current CF RunLoop, system key
> combos will not be captured.\n");
> +        return;
> +    }
> +
> +    CFRunLoopSourceRef tapEventsSrc =
> CFMachPortCreateRunLoopSource(kCFAllocatorDefault, eventsTap, 0);
> +    if (!tapEventsSrc ) {
> +        warn_report("Could not obtain current CF RunLoop, system key
> combos will not be captured.\n");
> +        return;
> +    }
> +
> +    CFRunLoopAddSource(runLoop, tapEventsSrc, kCFRunLoopDefaultMode);
> +    CFRelease(tapEventsSrc);
> +}
> +
>  - (void) toggleKey: (int)keycode {
>      qkbd_state_key_event(kbd, keycode, !qkbd_state_key_get(kbd, keycode));
>  }
> @@ -1284,6 +1334,13 @@ QemuCocoaView *cocoaView;
>      [cocoaView toggleFullScreen:sender];
>  }
>
> +- (void) setFullGrab:(id)sender
> +{
> +    COCOA_DEBUG("QemuCocoaAppController: setFullGrab\n");
> +
> +    [cocoaView setFullGrab:sender];
> +}
> +
>  /* Tries to find then open the specified filename */
>  - (void) openDocumentation: (NSString *) filename
>  {
> @@ -2060,11 +2117,17 @@ static void cocoa_display_init(DisplayState *ds,
> DisplayOptions *opts)
>      qemu_sem_wait(&app_started_sem);
>      COCOA_DEBUG("cocoa_display_init: app start completed\n");
>
> +    QemuCocoaAppController *controller = (QemuCocoaAppController
> *)[[NSApplication sharedApplication] delegate];
>      /* if fullscreen mode is to be used */
>      if (opts->has_full_screen && opts->full_screen) {
>          dispatch_async(dispatch_get_main_queue(), ^{
>              [NSApp activateIgnoringOtherApps: YES];
> -            [(QemuCocoaAppController *)[[NSApplication sharedApplication]
> delegate] toggleFullScreen: nil];
> +            [controller toggleFullScreen: nil];
> +        });
> +    }
> +    if (opts->u.cocoa.has_full_grab && opts->u.cocoa.full_grab) {
> +        dispatch_async(dispatch_get_main_queue(), ^{
> +            [controller setFullGrab: nil];
>          });
>      }
>
> --
> 2.34.1
>
> Reviewed-by: Will Cohen <wwcohen@gmail.com>

[-- Attachment #2: Type: text/html, Size: 9326 bytes --]