feat: Implement Toc service

src/.eslintrc.js

@@ -0,0 +1,6 @@
+module.exports = {
+    extends: ['../.eslintrc.js'],
+    rules: {
+        'valid-jsdoc': 'off',
+    },
+};

src/commands/build/core/toc/TocService.ts

@@ -0,0 +1,226 @@
+import type {BuildConfig, Run} from '~/commands/build';
+import type {IncluderOptions, RawToc, RawTocItem, Toc, TocItem, WithItems} from './types';
+
+import {ok} from 'node:assert';
+import {basename, dirname, join} from 'node:path';
+import {dump, load} from 'js-yaml';
+import {AsyncParallelHook, AsyncSeriesWaterfallHook, HookMap} from 'tapable';
+
+import {freeze, intercept, isExternalHref, normalizePath, own} from '~/utils';
+import {Stage} from '~/constants';
+
+import {IncludeMode, LoaderContext, loader} from './loader';
+
+export type TocServiceConfig = {
+    ignore: BuildConfig['ignore'];
+    ignoreStage: BuildConfig['ignoreStage'];
+    template: BuildConfig['template'];
+    removeHiddenTocItems: BuildConfig['removeHiddenTocItems'];
+};
+
+type WalkStepResult<I> = I | I[] | null | undefined;
+
+type TocServiceHooks = {
+    /**
+     * Called before item data processing (but after data interpolation)
+     */
+    Item: AsyncSeriesWaterfallHook<[RawTocItem, RelativePath]>;
+    Includer: HookMap<AsyncSeriesWaterfallHook<[RawToc, IncluderOptions, RelativePath]>>;
+    Resolved: AsyncParallelHook<[Toc, RelativePath]>;
+    Included: AsyncParallelHook<[Toc, RelativePath, IncludeInfo]>;
+};
+
+type IncludeInfo = {
+    from: RelativePath;
+    mode: IncludeMode;
+    mergeBase?: RelativePath;
+    content?: RawToc;
+};
+
+export class TocService {
+    hooks: TocServiceHooks;
+
+    get entries() {
+        return [...this._entries];
+    }
+
+    private run: Run;
+
+    private logger: Run['logger'];
+
+    private vars: Run['vars'];
+
+    private config: TocServiceConfig;
+
+    private tocs: Map<NormalizedPath, Toc> = new Map();
+
+    private _entries: Set<NormalizedPath> = new Set();
+
+    private processed: Hash<boolean> = {};
+
+    constructor(run: Run) {
+        this.run = run;
+        this.logger = run.logger;
+        this.vars = run.vars;
+        this.config = run.config;
+        this.hooks = intercept('TocService', {
+            Item: new AsyncSeriesWaterfallHook(['item', 'path']),
+            Includer: new HookMap(() => new AsyncSeriesWaterfallHook(['toc', 'options', 'path'])),
+            Resolved: new AsyncParallelHook(['toc', 'path']),
+            Included: new AsyncParallelHook(['toc', 'path', 'info']),
+        });
+    }
+
+    async init() {
+        const tocs = await this.run.glob('**/toc.yaml', {
+            cwd: this.run.input,
+            ignore: this.config.ignore,
+        });
+
+        for (const toc of tocs) {
+            await this.load(toc);
+        }
+    }
+
+    async load(path: RelativePath, include?: IncludeInfo): Promise<Toc | undefined> {
+        path = normalizePath(path);
+
+        // There is no error. We really skip toc processing, if it was processed previously in any way.
+        // For example toc can be processed as include of some other toc.
+        if (!include && this.processed[path]) {
+            return;
+        }
+
+        this.processed[path] = true;
+
+        this.logger.proc(path);
+
+        const file = join(this.run.input, path);
+
+        ok(file.startsWith(this.run.input), `Requested toc '${file}' is out of project scope.`);
+
+        const context: LoaderContext = {
+            mode: include?.mode || IncludeMode.RootMerge,
+            linkBase: include?.from || dirname(path),
+            mergeBase: include?.mergeBase,
+            path,
+            vars: await this.vars.load(path),
+            toc: this,
+            options: {
+                resolveConditions: this.config.template.features.conditions,
+                resolveSubstitutions: this.config.template.features.substitutions,
+                removeHiddenItems: this.config.removeHiddenTocItems,
+            },
+        };
+
+        const content = include?.content || (load(await this.run.read(file)) as RawToc);
+
+        // Should ignore included toc with tech-preview stage.
+        // TODO(major): remove this
+        if (content && content.stage === Stage.TECH_PREVIEW) {
+            return;
+        }
+
+        const {ignoreStage} = this.config;
+        if (content.stage && ignoreStage.length && ignoreStage.includes(content.stage)) {
+            return;
+        }
+
+        if (include && [IncludeMode.RootMerge, IncludeMode.Merge].includes(include.mode)) {
+            const from = dirname(file);
+            const to = join(this.run.input, include.mergeBase || dirname(include.from));
+            await this.run.copy(from, to, {
+                sourcePath: (file: string) => file.endsWith('.md'),
+                ignore: [basename(file), '**/toc.yaml'],
+            });
+        }
+
+        const toc = (await loader.call(context, content)) as Toc;
+
+        // If this is a part of other toc.yaml
+        if (include) {
+            await this.hooks.Included.promise(toc, path, include);
+        } else {
+            // TODO: we don't need to store tocs in future
+            // All processing should subscribe on toc.hooks.Resolved
+            this.tocs.set(path as NormalizedPath, toc);
+            await this.walkItems([toc], (item: TocItem | Toc) => {
+                if (own<string>(item, 'href') && !isExternalHref(item.href)) {
+                    this._entries.add(normalizePath(join(dirname(path), item.href)));
+                }
+
+                return item;
+            });
+
+            await this.hooks.Resolved.promise(freeze(toc), path);
+        }
+
+        // eslint-disable-next-line consistent-return
+        return toc;
+    }
+
+    dump(toc: Toc | undefined) {
+        ok(toc, 'Toc is empty.');
+
+        return dump(toc);
+    }
+
+    /**
+     * Visits all passed items. Applies actor to each item.
+     * Then applies actor to each item in actor result.items.
+     * Returns actor results.
+     */
+    async walkItems<T extends WithItems<T>>(
+        items: T[] | undefined,
+        actor: (item: T) => Promise<WalkStepResult<T>> | WalkStepResult<T>,
+    ): Promise<T[] | undefined> {
+        if (!items || !items.length) {
+            return items;
+        }
+
+        const results: T[] = [];
+        const queue = [...items];
+        while (queue.length) {
+            const item = queue.shift() as T;
+
+            const result = await actor(item);
+            if (result) {
+                results.push(...([] as T[]).concat(result));
+            }
+        }
+
+        for (const result of results) {
+            if (own(result, 'items') && result.items?.length) {
+                result.items = await this.walkItems(result.items, actor);
+            }
+        }
+
+        return results;
+    }
+
+    /**
+     * Resolves toc path and data for any page path.
+     * Expects what all paths are already loaded in service.
+     */
+    for(path: RelativePath): [RelativePath, Toc] {
+        path = normalizePath(path);
+
+        if (!path) {
+            throw new Error('Error while finding toc dir.');
+        }
+
+        const tocPath = join(dirname(path), 'toc.yaml');
+
+        if (this.tocs.has(tocPath as NormalizedPath)) {
+            return [tocPath, this.tocs.get(tocPath as NormalizedPath) as Toc];
+        }
+
+        return this.for(dirname(path));
+    }
+
+    dir(path: RelativePath): RelativePath {
+        const [tocPath] = this.for(path);
+
+        return dirname(tocPath);
+    }
+}