gnome-shell/js/ui/grabHelper.js

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// -*- mode: js; js-indent-level: 4; indent-tabs-mode: nil -*-
const Clutter = imports.gi.Clutter;
const Gtk = imports.gi.Gtk;
const Lang = imports.lang;
const Meta = imports.gi.Meta;
const Shell = imports.gi.Shell;
const St = imports.gi.St;
const Main = imports.ui.main;
const Params = imports.misc.params;
// GrabHelper:
// @owner: the actor that owns the GrabHelper
// @params: optional parameters to pass to Main.pushModal()
//
// Creates a new GrabHelper object, for dealing with keyboard and pointer grabs
// associated with a set of actors.
//
// Note that the grab can be automatically dropped at any time by the user, and
// your code just needs to deal with it; you shouldn't adjust behavior directly
// after you call ungrab(), but instead pass an 'onUngrab' callback when you
// call grab().
const GrabHelper = new Lang.Class({
Name: 'GrabHelper',
_init: function(owner, params) {
this._owner = owner;
this._modalParams = params;
this._grabStack = [];
this._actors = [];
this._capturedEventId = 0;
this._keyFocusNotifyId = 0;
this._focusWindowChangedId = 0;
this._ignoreRelease = false;
this._isUngrabbingCount = 0;
this._modalCount = 0;
this._grabFocusCount = 0;
},
// addActor:
// @actor: an actor
//
// Adds @actor to the set of actors that are allowed to process events
// during a grab.
addActor: function(actor) {
actor.__grabHelperDestroyId = actor.connect('destroy', Lang.bind(this, function() { this.removeActor(actor); }));
this._actors.push(actor);
},
// removeActor:
// @actor: an actor
//
// Removes @actor from the set of actors that are allowed to
// process events during a grab.
removeActor: function(actor) {
let index = this._actors.indexOf(actor);
if (index != -1)
this._actors.splice(index, 1);
if (actor.__grabHelperDestroyId) {
actor.disconnect(actor.__grabHelperDestroyId);
delete actor.__grabHelperDestroyId;
}
},
_isWithinGrabbedActor: function(actor) {
let currentActor = this.currentGrab.actor;
while (actor) {
if (this._actors.indexOf(actor) != -1)
return true;
if (actor == currentActor)
return true;
actor = actor.get_parent();
}
return false;
},
get currentGrab() {
return this._grabStack[this._grabStack.length - 1] || {};
},
get grabbed() {
return this._grabStack.length > 0;
},
get grabStack() {
return this._grabStack;
},
_findStackIndex: function(actor) {
if (!actor)
return -1;
for (let i = 0; i < this._grabStack.length; i++) {
if (this._grabStack[i].actor === actor)
return i;
}
return -1;
},
_actorInGrabStack: function(actor) {
while (actor) {
let idx = this._findStackIndex(actor);
if (idx >= 0)
return idx;
actor = actor.get_parent();
}
return -1;
},
isActorGrabbed: function(actor) {
return this._findStackIndex(actor) >= 0;
},
// grab:
// @params: A bunch of parameters, see below
//
// Grabs the mouse and keyboard, according to the GrabHelper's
// parameters. If @newFocus is not %null, then the keyboard focus
// is moved to the first #StWidget:can-focus widget inside it.
//
// The grab will automatically be dropped if:
// - The user clicks outside the grabbed actors
// - The user types Escape
// - The keyboard focus is moved outside the grabbed actors
// - A window is focused
//
// If @params.actor is not null, then it will be focused as the
// new actor. If you attempt to grab an already focused actor, the
// request to be focused will be ignored. The actor will not be
// added to the grab stack, so do not call a paired ungrab().
//
// If @params contains { modal: true }, then grab() will push a modal
// on the owner of the GrabHelper. As long as there is at least one
// { modal: true } actor on the grab stack, the grab will be kept.
// When the last { modal: true } actor is ungrabbed, then the modal
// will be dropped. A modal grab can fail if there is already a grab
// in effect from aother application; in this case the function returns
// false and nothing happens. Non-modal grabs can never fail.
//
// If @params contains { grabFocus: true }, then if you call grab()
// while the shell is outside the overview, it will set the stage
// input mode to %Shell.StageInputMode.FOCUSED, and ungrab() will
// revert it back, and re-focus the previously-focused window (if
// another window hasn't been explicitly focused before then).
grab: function(params) {
params = Params.parse(params, { actor: null,
modal: false,
grabFocus: false,
focus: null,
onUngrab: null });
let focus = global.stage.key_focus;
let hadFocus = focus && this._isWithinGrabbedActor(focus);
let newFocus = params.actor;
if (this.isActorGrabbed(params.actor))
return true;
params.savedFocus = focus;
if (params.modal && !this._takeModalGrab())
return false;
if (params.grabFocus && !this._takeFocusGrab(hadFocus))
return false;
this._grabStack.push(params);
if (params.focus) {
params.focus.grab_key_focus();
} else if (newFocus && (hadFocus || params.grabFocus)) {
if (!newFocus.navigate_focus(null, Gtk.DirectionType.TAB_FORWARD, false))
newFocus.grab_key_focus();
}
if ((params.grabFocus || params.modal) && !this._capturedEventId)
this._capturedEventId = global.stage.connect('captured-event', Lang.bind(this, this._onCapturedEvent));
return true;
},
_takeModalGrab: function() {
let firstGrab = (this._modalCount == 0);
if (firstGrab) {
if (!Main.pushModal(this._owner, this._modalParams))
return false;
}
this._modalCount++;
return true;
},
_releaseModalGrab: function() {
this._modalCount--;
if (this._modalCount > 0)
return;
Main.popModal(this._owner);
global.sync_pointer();
},
_takeFocusGrab: function(hadFocus) {
let firstGrab = (this._grabFocusCount == 0);
if (firstGrab) {
let metaDisplay = global.screen.get_display();
this._grabbedFromKeynav = hadFocus;
this._preGrabInputMode = global.stage_input_mode;
if (this._preGrabInputMode == Shell.StageInputMode.NONREACTIVE ||
this._preGrabInputMode == Shell.StageInputMode.NORMAL) {
global.set_stage_input_mode(Shell.StageInputMode.FOCUSED);
}
this._keyFocusNotifyId = global.stage.connect('notify::key-focus', Lang.bind(this, this._onKeyFocusChanged));
this._focusWindowChangedId = metaDisplay.connect('notify::focus-window', Lang.bind(this, this._focusWindowChanged));
}
this._grabFocusCount++;
return true;
},
_releaseFocusGrab: function() {
this._grabFocusCount--;
if (this._grabFocusCount > 0)
return;
if (this._keyFocusNotifyId > 0) {
global.stage.disconnect(this._keyFocusNotifyId);
this._keyFocusNotifyId = 0;
}
if (this._focusWindowChangedId > 0) {
let metaDisplay = global.screen.get_display();
metaDisplay.disconnect(this._focusWindowChangedId);
this._focusWindowChangedId = 0;
}
let prePopInputMode = global.stage_input_mode;
if (this._grabbedFromKeynav) {
if (this._preGrabInputMode == Shell.StageInputMode.FOCUSED &&
prePopInputMode != Shell.StageInputMode.FULLSCREEN)
global.set_stage_input_mode(Shell.StageInputMode.FOCUSED);
}
global.screen.focus_default_window(global.display.get_current_time_roundtrip());
},
// ignoreRelease:
//
// Make sure that the next button release event evaluated by the
// capture event handler returns false. This is designed for things
// like the ComboBoxMenu that go away on press, but need to eat
// the next release event.
ignoreRelease: function() {
this._ignoreRelease = true;
},
// ungrab:
// @params: The parameters for the grab; see below.
//
// Pops an actor from the grab stack, potentially dropping the grab.
//
// If the actor that was popped from the grab stack was not the actor
// That was passed in, this call is ignored.
ungrab: function(params) {
params = Params.parse(params, { actor: this.currentGrab.actor,
isUser: false });
let grabStackIndex = this._findStackIndex(params.actor);
if (grabStackIndex < 0)
return;
// We may get key focus changes when calling onUngrab, which
// would cause an extra ungrab() on the next actor in the
// stack, which is wrong. Ignore key focus changes during the
// ungrab, and restore the saved key focus ourselves afterwards.
// We use a count as ungrab() may be re-entrant, as onUngrab()
// may ungrab additional actors.
this._isUngrabbingCount++;
let focus = global.stage.key_focus;
let hadFocus = focus && this._isWithinGrabbedActor(focus);
let poppedGrabs = this._grabStack.slice(grabStackIndex);
// "Pop" all newly ungrabbed actors off the grab stack
// by truncating the array.
this._grabStack.length = grabStackIndex;
for (let i = poppedGrabs.length - 1; i >= 0; i--) {
let poppedGrab = poppedGrabs[i];
if (poppedGrab.onUngrab)
poppedGrab.onUngrab(params.isUser);
if (poppedGrab.modal)
this._releaseModalGrab();
if (poppedGrab.grabFocus)
this._releaseFocusGrab();
}
if (!this.grabbed && this._capturedEventId > 0) {
global.stage.disconnect(this._capturedEventId);
this._capturedEventId = 0;
}
if (hadFocus) {
let poppedGrab = poppedGrabs[0];
if (poppedGrab.savedFocus)
poppedGrab.savedFocus.grab_key_focus();
}
this._isUngrabbingCount--;
},
_onCapturedEvent: function(actor, event) {
let type = event.type();
if (type == Clutter.EventType.KEY_PRESS &&
event.get_key_symbol() == Clutter.KEY_Escape) {
this.ungrab({ isUser: true });
return true;
}
let press = type == Clutter.EventType.BUTTON_PRESS;
let release = type == Clutter.EventType.BUTTON_RELEASE;
let button = press || release;
if (release && this._ignoreRelease) {
this._ignoreRelease = false;
return true;
}
if (!button && this._modalCount == 0)
return false;
if (this._isWithinGrabbedActor(event.get_source()))
return false;
if (Main.keyboard.shouldTakeEvent(event))
return false;
if (button) {
// If we have a press event, ignore the next event,
// which should be a release event.
if (press)
this._ignoreRelease = true;
let i = this._actorInGrabStack(event.get_source()) + 1;
this.ungrab({ actor: this._grabStack[i].actor, isUser: true });
}
return this._modalCount > 0;
},
_onKeyFocusChanged: function() {
if (this._isUngrabbingCount > 0)
return;
let focus = global.stage.key_focus;
if (!focus || !this._isWithinGrabbedActor(focus))
this.ungrab({ isUser: true });
},
_focusWindowChanged: function() {
let metaDisplay = global.screen.get_display();
if (metaDisplay.focus_window != null)
this.ungrab({ isUser: true });
}
});