refactor: Extract parsing logic from Linter (#18790)

nzakas · mdjermanovic · web-flow · commit e1126423db08 · 2024-08-23T09:11:38.000+02:00
* refactor: Extract parsing logic from Linter refs #18787 * Clean up type information * Update lib/linter/linter.js Co-authored-by: Milos Djermanovic <milos.djermanovic@gmail.com> * Update lib/services/parser-service.js Co-authored-by: Milos Djermanovic <milos.djermanovic@gmail.com> --------- Co-authored-by: Milos Djermanovic <milos.djermanovic@gmail.com>
diff --git a/lib/linter/linter.js b/lib/linter/linter.js
@@ -55,6 +55,7 @@ const DEFAULT_ERROR_LOC = { start: { line: 1, column: 0 }, end: { line: 1, colum
 const parserSymbol = Symbol.for("eslint.RuleTester.parser");
 const { LATEST_ECMA_VERSION } = require("../../conf/ecma-version");
 const { VFile } = require("./vfile");
+const { ParserService } = require("../services/parser-service");
 const STEP_KIND_VISIT = 1;
 const STEP_KIND_CALL = 2;
 
@@ -922,43 +923,6 @@ function analyzeScope(ast, languageOptions, visitorKeys) {
     });
 }
 
-/**
- * Parses file into an AST. Moved out here because the try-catch prevents
- * optimization of functions, so it's best to keep the try-catch as isolated
- * as possible
- * @param {VFile} file The file to parse.
- * @param {Language} language The language to use.
- * @param {LanguageOptions} languageOptions Options to pass to the parser
- * @returns {{success: false, error: LintMessage}|{success: true, sourceCode: SourceCode}}
- * An object containing the AST and parser services if parsing was successful, or the error if parsing failed
- * @private
- */
-function parse(file, language, languageOptions) {
-
-    const result = language.parse(file, { languageOptions });
-
-    if (result.ok) {
-        return {
-            success: true,
-            sourceCode: language.createSourceCode(file, result, { languageOptions })
-        };
-    }
-
-    // if we made it to here there was an error
-    return {
-        success: false,
-        errors: result.errors.map(error => ({
-            ruleId: null,
-            nodeType: null,
-            fatal: true,
-            severity: 2,
-            message: `Parsing error: ${error.message}`,
-            line: error.line,
-            column: error.column
-        }))
-    };
-}
-
 /**
  * Runs a rule, and gets its listeners
  * @param {Rule} rule A rule object
@@ -1407,10 +1371,13 @@ class Linter {
                 t = startTime();
             }
 
-            const parseResult = parse(
+            const parserService = new ParserService();
+            const parseResult = parserService.parseSync(
                 file,
-                jslang,
-                languageOptions
+                {
+                    language: jslang,
+                    languageOptions
+                }
             );
 
             if (options.stats) {
@@ -1420,7 +1387,7 @@ class Linter {
                 storeTime(time, timeOpts, slots);
             }
 
-            if (!parseResult.success) {
+            if (!parseResult.ok) {
                 return parseResult.errors;
             }
 
@@ -1712,10 +1679,10 @@ class Linter {
                 t = startTime();
             }
 
-            const parseResult = parse(
+            const parserService = new ParserService();
+            const parseResult = parserService.parseSync(
                 file,
-                config.language,
-                languageOptions
+                config
             );
 
             if (options.stats) {
@@ -1724,7 +1691,7 @@ class Linter {
                 storeTime(time, { type: "parse" }, slots);
             }
 
-            if (!parseResult.success) {
+            if (!parseResult.ok) {
                 return parseResult.errors;
             }
 
diff --git a/lib/services/parser-service.js b/lib/services/parser-service.js
@@ -0,0 +1,65 @@
+/**
+ * @fileoverview ESLint Parser
+ * @author Nicholas C. Zakas
+ */
+/* eslint class-methods-use-this: off -- Anticipate future constructor arguments. */
+
+"use strict";
+
+//-----------------------------------------------------------------------------
+// Types
+//-----------------------------------------------------------------------------
+
+/** @typedef {import("../linter/vfile.js").VFile} VFile */
+/** @typedef {import("@eslint/core").Language} Language */
+/** @typedef {import("@eslint/core").LanguageOptions} LanguageOptions */
+
+//-----------------------------------------------------------------------------
+// Exports
+//-----------------------------------------------------------------------------
+
+/**
+ * The parser for ESLint.
+ */
+class ParserService {
+
+    /**
+     * Parses the given file synchronously.
+     * @param {VFile} file The file to parse.
+     * @param {{language:Language,languageOptions:LanguageOptions}} config The configuration to use.
+     * @returns {Object} An object with the parsed source code or errors.
+     * @throws {Error} If the parser returns a promise.
+     */
+    parseSync(file, config) {
+
+        const { language, languageOptions } = config;
+        const result = language.parse(file, { languageOptions });
+
+        if (typeof result.then === "function") {
+            throw new Error("Unsupported: Language parser returned a promise.");
+        }
+
+        if (result.ok) {
+            return {
+                ok: true,
+                sourceCode: language.createSourceCode(file, result, { languageOptions })
+            };
+        }
+
+        // if we made it to here there was an error
+        return {
+            ok: false,
+            errors: result.errors.map(error => ({
+                ruleId: null,
+                nodeType: null,
+                fatal: true,
+                severity: 2,
+                message: `Parsing error: ${error.message}`,
+                line: error.line,
+                column: error.column
+            }))
+        };
+    }
+}
+
+module.exports = { ParserService };
