@angular-devkit/core/src/virtual-fs/host/alias.js

Angular DevKit - Core Utility Library

"use strict";
/**
 * @license
 * Copyright Google LLC All Rights Reserved.
 *
 * Use of this source code is governed by an MIT-style license that can be
 * found in the LICENSE file at https://angular.dev/license
 */
Object.defineProperty(exports, "__esModule", { value: true });
exports.AliasHost = void 0;
const path_1 = require("../path");
const resolver_1 = require("./resolver");
/**
 * A Virtual Host that allow to alias some paths to other paths.
 *
 * This does not verify, when setting an alias, that the target or source exist. Neither does it
 * check whether it's a file or a directory. Please not that directories are also renamed/replaced.
 *
 * No recursion is done on the resolution, which means the following is perfectly valid then:
 *
 * ```
 *     host.aliases.set(normalize('/file/a'), normalize('/file/b'));
 *     host.aliases.set(normalize('/file/b'), normalize('/file/a'));
 * ```
 *
 * This will result in a proper swap of two files for each others.
 *
 * @example
 *   const host = new SimpleMemoryHost();
 *   host.write(normalize('/some/file'), content).subscribe();
 *
 *   const aHost = new AliasHost(host);
 *   aHost.read(normalize('/some/file'))
 *     .subscribe(x => expect(x).toBe(content));
 *   aHost.aliases.set(normalize('/some/file'), normalize('/other/path');
 *
 *   // This file will not exist because /other/path does not exist.
 *   aHost.read(normalize('/some/file'))
 *     .subscribe(undefined, err => expect(err.message).toMatch(/does not exist/));
 *
 * @example
 *   const host = new SimpleMemoryHost();
 *   host.write(normalize('/some/folder/file'), content).subscribe();
 *
 *   const aHost = new AliasHost(host);
 *   aHost.read(normalize('/some/folder/file'))
 *     .subscribe(x => expect(x).toBe(content));
 *   aHost.aliases.set(normalize('/some'), normalize('/other');
 *
 *   // This file will not exist because /other/path does not exist.
 *   aHost.read(normalize('/some/folder/file'))
 *     .subscribe(undefined, err => expect(err.message).toMatch(/does not exist/));
 *
 *   // Create the file with new content and verify that this has the new content.
 *   aHost.write(normalize('/other/folder/file'), content2).subscribe();
 *   aHost.read(normalize('/some/folder/file'))
 *     .subscribe(x => expect(x).toBe(content2));
 */
class AliasHost extends resolver_1.ResolverHost {
    _aliases = new Map();
    _resolve(path) {
        let maybeAlias = this._aliases.get(path);
        const sp = (0, path_1.split)(path);
        const remaining = [];
        // Also resolve all parents of the requested files, only picking the first one that matches.
        // This can have surprising behaviour when aliases are inside another alias. It will always
        // use the closest one to the file.
        while (!maybeAlias && sp.length > 0) {
            const p = (0, path_1.join)(path_1.NormalizedRoot, ...sp);
            maybeAlias = this._aliases.get(p);
            if (maybeAlias) {
                maybeAlias = (0, path_1.join)(maybeAlias, ...remaining);
            }
            // Allow non-null-operator because we know sp.length > 0 (condition on while).
            remaining.unshift(sp.pop()); // eslint-disable-line @typescript-eslint/no-non-null-assertion
        }
        return maybeAlias || path;
    }
    get aliases() {
        return this._aliases;
    }
}
exports.AliasHost = AliasHost;