55 lines
1.4 KiB
TypeScript
55 lines
1.4 KiB
TypeScript
import {
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RootFolderNode, FolderUnion, FolderNodeMedial, FolderNodeInitial,
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} from "./interfaces";
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import { defensiveClone } from "../util";
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interface TreeClimberState {
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active: boolean;
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}
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interface VisitorProps {
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node: FolderNodeInitial | FolderNodeMedial;
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callback: TreeClimber;
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halt: Halt;
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state: TreeClimberState;
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}
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type Halt = () => RootFolderNode;
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type TreeClimber = (t: FolderUnion,
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/** Calling this function stops tree climb from continuing. */
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halt: Halt) => void;
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function visit(p: VisitorProps) {
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const { node, callback, halt } = p;
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callback(node, halt);
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const children: FolderUnion[] = (node.children);
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return p.state.active && children.map(nextNode => {
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if (nextNode.kind != "terminal") {
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p.state.active && visit({ ...p, node: nextNode });
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} else {
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p.state.active && callback(nextNode, p.halt);
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}
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});
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}
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/** Recursively climb a directory structure. */
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export const climb = (t: RootFolderNode, callback: TreeClimber) => {
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const state: TreeClimberState = { active: true };
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const halt = () => {
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state.active = false;
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return t;
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};
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t.folders.map((node) => {
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const props = { node, callback, halt, state };
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state.active && visit(props);
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});
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return t;
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};
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/** TODO: Create strategies for non-destructively
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* transforming a RootFolderNode. */
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export const cloneAndClimb = (t: RootFolderNode, callback: TreeClimber) => {
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return climb(defensiveClone(t), callback);
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};
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