diff options
Diffstat (limited to 'src/client/util/UndoManager.ts')
-rw-r--r-- | src/client/util/UndoManager.ts | 133 |
1 files changed, 133 insertions, 0 deletions
diff --git a/src/client/util/UndoManager.ts b/src/client/util/UndoManager.ts new file mode 100644 index 000000000..46ad558f3 --- /dev/null +++ b/src/client/util/UndoManager.ts @@ -0,0 +1,133 @@ +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); + }) + +}
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