Squashed 'lib/vscode/' content from commit e5a624b788

git-subtree-dir: lib/vscode
git-subtree-split: e5a624b788d92b8d34d1392e4c4d9789406efe8f

build/lib/eslint/code-layering.ts

@@ -0,0 +1,83 @@
+/*---------------------------------------------------------------------------------------------
+ *  Copyright (c) Microsoft Corporation. All rights reserved.
+ *  Licensed under the MIT License. See License.txt in the project root for license information.
+ *--------------------------------------------------------------------------------------------*/
+
+import * as eslint from 'eslint';
+import { join, dirname } from 'path';
+import { createImportRuleListener } from './utils';
+
+type Config = {
+	allowed: Set<string>;
+	disallowed: Set<string>;
+};
+
+export = new class implements eslint.Rule.RuleModule {
+
+	readonly meta: eslint.Rule.RuleMetaData = {
+		messages: {
+			layerbreaker: 'Bad layering. You are not allowed to access {{from}} from here, allowed layers are: [{{allowed}}]'
+		},
+		docs: {
+			url: 'https://github.com/microsoft/vscode/wiki/Source-Code-Organization'
+		}
+	};
+
+	create(context: eslint.Rule.RuleContext): eslint.Rule.RuleListener {
+
+		const fileDirname = dirname(context.getFilename());
+		const parts = fileDirname.split(/\\|\//);
+		const ruleArgs = <Record<string, string[]>>context.options[0];
+
+		let config: Config | undefined;
+		for (let i = parts.length - 1; i >= 0; i--) {
+			if (ruleArgs[parts[i]]) {
+				config = {
+					allowed: new Set(ruleArgs[parts[i]]).add(parts[i]),
+					disallowed: new Set()
+				};
+				Object.keys(ruleArgs).forEach(key => {
+					if (!config!.allowed.has(key)) {
+						config!.disallowed.add(key);
+					}
+				});
+				break;
+			}
+		}
+
+		if (!config) {
+			// nothing
+			return {};
+		}
+
+		return createImportRuleListener((node, path) => {
+			if (path[0] === '.') {
+				path = join(dirname(context.getFilename()), path);
+			}
+
+			const parts = dirname(path).split(/\\|\//);
+			for (let i = parts.length - 1; i >= 0; i--) {
+				const part = parts[i];
+
+				if (config!.allowed.has(part)) {
+					// GOOD - same layer
+					break;
+				}
+
+				if (config!.disallowed.has(part)) {
+					// BAD - wrong layer
+					context.report({
+						loc: node.loc,
+						messageId: 'layerbreaker',
+						data: {
+							from: part,
+							allowed: [...config!.allowed.keys()].join(', ')
+						}
+					});
+					break;
+				}
+			}
+		});
+	}
+};
+