1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
|
import { observable, action } from "mobx";
function propertyDecorator(target: any, key: string | symbol) {
Object.defineProperty(target, key, {
configurable: true,
enumerable: false,
get: function () {
return 5;
},
set: function (value: any) {
Object.defineProperty(this, key, {
enumerable: false,
writable: true,
configurable: true,
value: function (...args: any[]) {
try {
UndoManager.StartBatch();
return value.apply(this, args);
} finally {
UndoManager.EndBatch();
}
}
})
}
})
}
export function undoBatch(target: any, key: string | symbol, descriptor?: TypedPropertyDescriptor<any>): any {
if (!descriptor) {
propertyDecorator(target, key);
return;
}
const oldFunction = descriptor.value;
descriptor.value = function (...args: any[]) {
try {
UndoManager.StartBatch()
return oldFunction.apply(this, args)
} finally {
UndoManager.EndBatch()
}
}
return descriptor;
}
export namespace UndoManager {
export interface UndoEvent {
undo: () => void;
redo: () => void;
}
type UndoBatch = UndoEvent[];
let undoStack: UndoBatch[] = observable([]);
let redoStack: UndoBatch[] = observable([]);
let currentBatch: UndoBatch | undefined;
let batchCounter = 0;
let undoing = false;
export function AddEvent(event: UndoEvent): void {
if (currentBatch && batchCounter && !undoing) {
currentBatch.push(event);
}
}
export function CanUndo(): boolean {
return undoStack.length > 0;
}
export function CanRedo(): boolean {
return redoStack.length > 0;
}
export function StartBatch(): void {
batchCounter++;
if (batchCounter > 0) {
currentBatch = [];
}
}
export const EndBatch = action(() => {
batchCounter--;
if (batchCounter === 0 && currentBatch && currentBatch.length) {
undoStack.push(currentBatch);
redoStack.length = 0;
currentBatch = undefined;
}
})
export function RunInBatch(fn: () => void) {
StartBatch();
fn();
EndBatch();
}
export const Undo = action(() => {
if (undoStack.length === 0) {
return;
}
let commands = undoStack.pop();
if (!commands) {
return;
}
undoing = true;
for (let i = commands.length - 1; i >= 0; i--) {
commands[i].undo();
}
undoing = false;
redoStack.push(commands);
})
export const Redo = action(() => {
if (redoStack.length === 0) {
return;
}
let commands = redoStack.pop();
if (!commands) {
return;
}
undoing = true;
for (let i = 0; i < commands.length; i++) {
commands[i].redo();
}
undoing = false;
undoStack.push(commands);
})
}
|
