mute-structs/src/operations/delete/textdelete.ts

NodeJS module providing an implementation of the LogootSplit CRDT algorithm

/*
    This file is part of MUTE-structs.

    Copyright (C) 2017  Matthieu Nicolas, Victorien Elvinger

    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU Affero General Public License as
    published by the Free Software Foundation, either version 3 of the
    License, or (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU Affero General Public License for more details.

    You should have received a copy of the GNU Affero General Public License
    along with this program.  If not, see <https://www.gnu.org/licenses/>.
*/

import {isInt32} from "../../int32"
import {LogootSRopes} from "../../logootsropes"
import {TextOperation} from "../textoperation"
import {LogootSDel} from "./logootsdel"

/**
 * Represents a sequence operation (deletion).
 */
export class TextDelete extends TextOperation {

    readonly length: number

    /**
     * @constructor
     * @param {number} index - the position of the first element to be deleted in the sequence.
     * @param {number} length - the length of the range to be deleted in the sequence.
     * @param {number} author - the author of the operation.
     */
    constructor (index: number, length: number, author: number) {
        console.assert(isInt32(index), "index  ∈ int32")
        console.assert(isInt32(length), "length  ∈ int32")
        console.assert(length > 0, "length > 0")
        console.assert(isInt32(author), "author ∈ int32")

        super(index, author)
        this.length = length
    }

    equals (other: TextDelete): boolean {
        return this.index === other.index &&
            this.length === other.length
    }

    /**
     * Apply the current delete operation to a LogootSplit document.
     * @param {LogootSDocument} doc - the LogootSplit document on which the deletion wil be performed.
     * @return {LogootSDel} the logootsplit deletion that is related to the deletion that has been performed.
     */
    applyTo (doc: LogootSRopes): LogootSDel {
        return doc.delLocal(this.index, this.index + this.length - 1)
    }
}