90 lines
2.7 KiB
Swift
90 lines
2.7 KiB
Swift
/*
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* Copyright 2022 The Yorkie Authors. All rights reserved.
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*
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* Licensed under the Apache License, Version 2.0 (the "License")
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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import Foundation
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/**
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* `ChangeContext` is used to record the context of modification when editing
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* a document. Each time we add an operation, a new time ticket is issued.
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* Finally returns a Change after the modification has been completed.
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*/
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class ChangeContext {
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private let id: ChangeID
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private let root: CRDTRoot
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private var operations: [Operation]
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private let message: String?
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private var delimiter: UInt32
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init(id: ChangeID, root: CRDTRoot, message: String? = nil) {
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self.id = id
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self.root = root
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self.message = message
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self.operations = []
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self.delimiter = TimeTicket.Values.initialDelimiter
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}
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/**
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* `push` pushes the given operation to this context.
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*/
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func push(operation: Operation) {
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self.operations.append(operation)
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}
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/**
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* `registerElement` registers the given element to the root.
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*/
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func registerElement(_ element: CRDTElement, parent: CRDTContainer) {
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self.root.registerElement(element, parent: parent)
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}
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/**
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* `registerRemovedElement` register removed element for garbage collection.
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*/
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func registerRemovedElement(_ element: CRDTElement) {
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self.root.registerRemovedElement(element)
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}
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/**
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* `registerRemovedNodeTextElement` register text element has removed node for
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* garbage collection.
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*/
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func registerRemovedNodeTextElement(_ text: CRDTTextElement) {
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self.root.registerTextWithGarbage(text: text)
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}
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/**
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* `getChange` creates a new instance of Change in this context.
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*/
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func getChange() -> Change {
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return Change(id: self.id, operations: self.operations, message: self.message)
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}
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/**
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* `hasOperations` returns the whether this context has operations or not.
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*/
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func hasOperations() -> Bool {
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return self.operations.isEmpty == false
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}
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/**
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* `issueTimeTicket` creates a time ticket to be used to create a new operation.
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*/
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func issueTimeTicket() -> TimeTicket {
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self.delimiter += 1
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return self.id.createTimeTicket(delimiter: self.delimiter)
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}
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}
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