1/*
2 * Copyright (c) 2022-2023 Huawei Device Co., Ltd.
3 * Licensed under the Apache License, Version 2.0 (the "License");
4 * you may not use this file except in compliance with the License.
5 * You may obtain a copy of the License at
6 *
7 *     http://www.apache.org/licenses/LICENSE-2.0
8 *
9 * Unless required by applicable law or agreed to in writing, software
10 * distributed under the License is distributed on an "AS IS" BASIS,
11 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12 * See the License for the specific language governing permissions and
13 * limitations under the License.
14 */
15
16export class EditStack<T> {
17  private stack: T[] = [];
18  private currentPosition: number = -1;
19
20  isRedoValid(): boolean {
21    return (this.currentPosition < this.stack.length - 1);
22  }
23
24  isUndoValid(): boolean {
25    return (this.currentPosition >= 0);
26  }
27
28  redo(): number {
29    if (this.isRedoValid()) {
30      this.currentPosition++;
31    }
32    return this.currentPosition;
33  }
34
35  undo(): number {
36    if (this.isUndoValid()) {
37      this.currentPosition--;
38    }
39    return this.currentPosition;
40  }
41
42  reset(): void {
43    this.stack.length = 0;
44    this.currentPosition = -1;
45  }
46
47  getLength(): number {
48    return this.stack.length;
49  }
50
51  getPosition(): number {
52    return this.currentPosition;
53  }
54
55  at(index: number): T {
56    return this.stack[index];
57  }
58
59  push(obj: T): void {
60    let reserveLength = this.currentPosition + 1;
61    if (reserveLength < this.stack.length) {
62      this.stack.length = reserveLength;
63    }
64    this.currentPosition = this.stack.push(obj) - 1;
65  }
66
67  forEach(action: Function, count: number = this.currentPosition): void {
68    for (let i = 0; i <= count; ++i) {
69      action(this.stack[i]);
70    }
71  }
72}