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// -*- mode: js; js-indent-level: 4; indent-tabs-mode: nil -*-
/*
* Copyright 2011 Red Hat, Inc
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2, or (at your option)
* any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see <http://www.gnu.org/licenses/>.
*/
/*
* In order for transformation animations to look good, they need to be
* incremental and have some order to them (e.g., fade out hidden items,
* then shrink to close the void left over). Chaining animations in this way can
* be error-prone and wordy using just ease() callbacks.
*
* The classes in this file help with this:
*
* - Task. encapsulates schedulable work to be run in a specific scope.
*
* - ConsecutiveBatch. runs a series of tasks in order and completes
* when the last in the series finishes.
*
* - ConcurrentBatch. runs a set of tasks at the same time and completes
* when the last to finish completes.
*
* - Hold. prevents a batch from completing the pending task until
* the hold is released.
*
* The tasks associated with a batch are specified in a list at batch
* construction time as either task objects or plain functions.
* Batches are task objects, themselves, so they can be nested.
*
* These classes aren't specific to GDM, but were found to be unintuitive and so
* are not used elsewhere. These APIs may ultimately get dropped entirely and
* replaced by something else.
*/
/* exported ConcurrentBatch, ConsecutiveBatch */
const { GObject } = imports.gi;
const Signals = imports.misc.signals;
var Task = class extends Signals.EventEmitter {
constructor(scope, handler) {
super();
if (scope)
this.scope = scope;
else
this.scope = this;
this.handler = handler;
}
run() {
if (this.handler)
return this.handler.call(this.scope);
return null;
}
};
var Hold = class extends Task {
constructor() {
super(null, () => this);
this._acquisitions = 1;
}
acquire() {
if (this._acquisitions <= 0)
throw new Error("Cannot acquire hold after it's been released");
this._acquisitions++;
}
acquireUntilAfter(hold) {
if (!hold.isAcquired())
return;
this.acquire();
let signalId = hold.connect('release', () => {
hold.disconnect(signalId);
this.release();
});
}
release() {
this._acquisitions--;
if (this._acquisitions == 0)
this.emit('release');
}
isAcquired() {
return this._acquisitions > 0;
}
};
var Batch = class extends Task {
constructor(scope, tasks) {
super();
this.tasks = [];
for (let i = 0; i < tasks.length; i++) {
let task;
if (tasks[i] instanceof Task)
task = tasks[i];
else if (typeof tasks[i] == 'function')
task = new Task(scope, tasks[i]);
else
throw new Error('Batch tasks must be functions or Task, Hold or Batch objects');
this.tasks.push(task);
}
}
process() {
throw new GObject.NotImplementedError(`process in ${this.constructor.name}`);
}
runTask() {
if (!(this._currentTaskIndex in this.tasks))
return null;
return this.tasks[this._currentTaskIndex].run();
}
_finish() {
this.hold.release();
}
nextTask() {
this._currentTaskIndex++;
// if the entire batch of tasks is finished, release
// the hold and notify anyone waiting on the batch
if (this._currentTaskIndex >= this.tasks.length) {
this._finish();
return;
}
this.process();
}
_start() {
// acquire a hold to get released when the entire
// batch of tasks is finished
this.hold = new Hold();
this._currentTaskIndex = 0;
this.process();
}
run() {
this._start();
// hold may be destroyed at this point
// if we're already done running
return this.hold;
}
cancel() {
this.tasks = this.tasks.splice(0, this._currentTaskIndex + 1);
}
};
var ConcurrentBatch = class extends Batch {
process() {
let hold = this.runTask();
if (hold)
this.hold.acquireUntilAfter(hold);
// Regardless of the state of the just run task,
// fire off the next one, so all the tasks can run
// concurrently.
this.nextTask();
}
};
var ConsecutiveBatch = class extends Batch {
process() {
let hold = this.runTask();
if (hold && hold.isAcquired()) {
// This task is inhibiting the batch. Wait on it
// before processing the next one.
let signalId = hold.connect('release', () => {
hold.disconnect(signalId);
this.nextTask();
});
} else {
// This task finished, process the next one
this.nextTask();
}
}
};
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