107 lines
3.3 KiB
JavaScript
107 lines
3.3 KiB
JavaScript
import ID from './ID.js'
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class ReverseOperation {
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constructor (y, transaction) {
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this.created = new Date()
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const beforeState = transaction.beforeState
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this.toState = new ID(y.userID, y.ss.getState(y.userID) - 1)
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if (beforeState.has(y.userID)) {
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this.fromState = new ID(y.userID, beforeState.get(y.userID))
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} else {
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this.fromState = this.toState
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}
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this.deletedStructs = transaction.deletedStructs
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}
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}
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function isStructInScope (y, struct, scope) {
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while (struct !== y) {
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if (struct === scope) {
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return true
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}
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struct = struct._parent
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}
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return false
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}
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function applyReverseOperation (y, scope, reverseBuffer) {
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let performedUndo = false
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y.transact(() => {
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while (!performedUndo && reverseBuffer.length > 0) {
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let undoOp = reverseBuffer.pop()
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// make sure that it is possible to iterate {from}-{to}
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y.os.getItemCleanStart(undoOp.fromState)
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y.os.getItemCleanEnd(undoOp.toState)
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y.os.iterate(undoOp.fromState, undoOp.toState, op => {
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if (!op._deleted && isStructInScope(y, op, scope)) {
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performedUndo = true
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op._delete(y)
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}
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})
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for (let op of undoOp.deletedStructs) {
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if (
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isStructInScope(y, op, scope) &&
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op._parent !== y &&
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!op._parent._deleted &&
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(
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op._parent._id.user !== y.userID ||
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op._parent._id.clock < undoOp.fromState.clock ||
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op._parent._id.clock > undoOp.fromState.clock
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)
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) {
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performedUndo = true
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op = op._copy(undoOp.deletedStructs, true)
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op._integrate(y)
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}
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}
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}
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})
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return performedUndo
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}
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export default class UndoManager {
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constructor (scope, options = {}) {
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this.options = options
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options.captureTimeout = options.captureTimeout == null ? 500 : options.captureTimeout
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this._undoBuffer = []
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this._redoBuffer = []
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this._scope = scope
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this._undoing = false
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this._redoing = false
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const y = scope._y
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this.y = y
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y.on('afterTransaction', (y, transaction, remote) => {
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if (!remote && transaction.changedParentTypes.has(scope)) {
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let reverseOperation = new ReverseOperation(y, transaction)
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if (!this._undoing) {
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let lastUndoOp = this._undoBuffer.length > 0 ? this._undoBuffer[this._undoBuffer.length - 1] : null
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if (lastUndoOp !== null && reverseOperation.created - lastUndoOp.created <= options.captureTimeout) {
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lastUndoOp.created = reverseOperation.created
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lastUndoOp.toState = reverseOperation.toState
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reverseOperation.deletedStructs.forEach(lastUndoOp.deletedStructs.add, lastUndoOp.deletedStructs)
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} else {
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this._undoBuffer.push(reverseOperation)
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}
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if (!this._redoing) {
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this._redoBuffer = []
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}
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} else {
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this._redoBuffer.push(reverseOperation)
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}
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}
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})
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}
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undo () {
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this._undoing = true
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const performedUndo = applyReverseOperation(this.y, this._scope, this._undoBuffer)
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this._undoing = false
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return performedUndo
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}
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redo () {
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this._redoing = true
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const performedRedo = applyReverseOperation(this.y, this._scope, this._redoBuffer)
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this._redoing = false
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return performedRedo
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}
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}
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