blob: cfc1a462551eb1c2884605df997024338bace40c [file] [log] [blame]
// Copyright (C) 2019 The Android Open Source Project
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
import {publishLoading} from '../frontend/publish';
import {LoadingTracker} from '../trace_processor/engine';
// Used to keep track of whether the engine is currently querying.
export class LoadingManager implements LoadingTracker {
private static _instance: LoadingManager;
private numQueuedQueries = 0;
private numLastUpdate = 0;
static get getInstance(): LoadingManager {
// eslint-disable-next-line @typescript-eslint/strict-boolean-expressions
return this._instance || (this._instance = new this());
}
beginLoading() {
this.update(1);
}
endLoading() {
this.update(-1);
}
private update(change: number) {
this.numQueuedQueries += change;
if (
this.numQueuedQueries === 0 ||
Math.abs(this.numLastUpdate - this.numQueuedQueries) > 2
) {
this.numLastUpdate = this.numQueuedQueries;
publishLoading(this.numQueuedQueries);
}
}
}