idlize

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/*
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 * Copyright (c) 2022-2023 Huawei Device Co., Ltd.
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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 { int32, uint32 } from "@koalaui/compat"
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import { TreePath } from "./TreePath"
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/**
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 * This class provides basic functionality for tree building or incremental tree updating.
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 */
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export abstract class TreeUpdater<Node> {
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    private current: TreePath<Node>
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    readonly reverse: boolean
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    /**
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     * @param root     the tree root that always exists
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     * @param reverse  `false` builds a tree top-down, `true` build a tree bottom-up
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     */
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    constructor(root: Node, reverse: boolean = false) {
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        this.current = new TreePath<Node>(root)
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        this.reverse = reverse
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    }
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    /**
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     * Returns the path to the selected node.
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     */
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    get path(): TreePath<Node> {
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        return this.current
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    }
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    /**
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     * Returns the selected node to perform tree change operations.
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     */
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    get node(): Node {
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        return this.current.node
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    }
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    /**
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     * Selects the specified child node when the updater is getting traversed down the tree.
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     */
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    down(node: Node): void {
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        this.current = this.current.child(node)
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    }
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    /**
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     * Selects the parent node when the updater is getting traversed up the tree.
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     */
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    up(): void {
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        let parent = this.current.parent
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        if (parent === undefined) throw new Error("unexpected")
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        this.current = parent
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    }
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    /**
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     * Selects the root node to prepare the updater to traversing a tree.
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     */
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    clear(): void {
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        this.current = this.current.root
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    }
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    /**
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     * Inserts the specified node as a child of a selected node at the given index.
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     */
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    abstract insert(index: int32, node: Node): void
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    /**
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     * Removes the specified amount of children from the given index.
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     */
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    abstract remove(index: int32, amount: uint32): void
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    /**
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     * Moves the specified amount of children from the indexFrom to the indexTo.
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     */
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    abstract move(indexFrom: int32, indexTo: int32, amount: uint32): void
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}
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