module: implement module.registerHooks()

Author: joyeecheung

lib/internal/modules/cjs/loader.js

@@ -101,6 +101,7 @@ const kIsCachedByESMLoader = Symbol('kIsCachedByESMLoader');
 const kRequiredModuleSymbol = Symbol('kRequiredModuleSymbol');
 const kIsExecuting = Symbol('kIsExecuting');
 
+const kURL = Symbol('kURL');
 const kFormat = Symbol('kFormat');
 
 // Set first due to cycle with ESM loader functions.
@@ -111,6 +112,9 @@ module.exports = {
   kModuleCircularVisited,
   initializeCJS,
   Module,
+  findLongestRegisteredExtension,
+  resolveForCJSWithHooks,
+  loadSourceForCJSWithHooks: loadSource,
   wrapSafe,
   wrapModuleLoad,
   kIsMainSymbol,
@@ -155,6 +159,13 @@ const {
   stripBOM,
   toRealPath,
 } = require('internal/modules/helpers');
+const {
+  convertCJSFilenameToURL,
+  convertURLToCJSFilename,
+  loadWithHooks,
+  registerHooks,
+  resolveWithHooks,
+} = require('internal/modules/sync_hooks');
 const { stripTypeScriptModuleTypes } = require('internal/modules/typescript');
 const packageJsonReader = require('internal/modules/package_json_reader');
 const { getOptionValue, getEmbedderOptions } = require('internal/options');
@@ -584,7 +595,7 @@ function trySelfParentPath(parent) {
  * @param {string} parentPath The path of the parent module
  * @param {string} request The module request to resolve
  */
-function trySelf(parentPath, request) {
+function trySelf(parentPath, request, conditions) {
   if (!parentPath) { return false; }
 
   const pkg = packageJsonReader.getNearestParentPackageJSON(parentPath);
@@ -605,7 +616,7 @@ function trySelf(parentPath, request) {
     const { packageExportsResolve } = require('internal/modules/esm/resolve');
     return finalizeEsmResolution(packageExportsResolve(
       pathToFileURL(pkg.path), expansion, pkg.data,
-      pathToFileURL(parentPath), getCjsConditions()), parentPath, pkg.path);
+      pathToFileURL(parentPath), conditions), parentPath, pkg.path);
   } catch (e) {
     if (e.code === 'ERR_MODULE_NOT_FOUND') {
       throw createEsmNotFoundErr(request, pkg.path);
@@ -626,7 +637,7 @@ const EXPORTS_PATTERN = /^((?:@[^/\\%]+\/)?[^./\\%][^/\\%]*)(\/.*)?$/;
  * @param {string} nmPath The path to the module.
  * @param {string} request The request for the module.
  */
-function resolveExports(nmPath, request) {
+function resolveExports(nmPath, request, conditions) {
   // The implementation's behavior is meant to mirror resolution in ESM.
   const { 1: name, 2: expansion = '' } =
     RegExpPrototypeExec(EXPORTS_PATTERN, request) || kEmptyObject;
@@ -638,7 +649,7 @@ function resolveExports(nmPath, request) {
       const { packageExportsResolve } = require('internal/modules/esm/resolve');
       return finalizeEsmResolution(packageExportsResolve(
         pathToFileURL(pkgPath + '/package.json'), '.' + expansion, pkg, null,
-        getCjsConditions()), null, pkgPath);
+        conditions), null, pkgPath);
     } catch (e) {
       if (e.code === 'ERR_MODULE_NOT_FOUND') {
         throw createEsmNotFoundErr(request, pkgPath + '/package.json');
@@ -680,7 +691,7 @@ function getDefaultExtensions() {
  * @param {boolean} isMain Whether the request is the main app entry point
  * @returns {string | false}
  */
-Module._findPath = function(request, paths, isMain) {
+Module._findPath = function(request, paths, isMain, conditions = getCjsConditions()) {
   const absoluteRequest = path.isAbsolute(request);
   if (absoluteRequest) {
     paths = [''];
@@ -738,7 +749,7 @@ Module._findPath = function(request, paths, isMain) {
     }
 
     if (!absoluteRequest) {
-      const exportsResolved = resolveExports(curPath, request);
+      const exportsResolved = resolveExports(curPath, request, conditions);
       if (exportsResolved) {
         return exportsResolved;
       }
@@ -1019,6 +1030,50 @@ function getExportsForCircularRequire(module) {
   return module.exports;
 }
 
+/**
+ * Resolve a module request for CommonJS
+ * @param {string} specifier
+ * @param {Module|undefined} parent
+ * @param {boolean} isMain
+ * @returns {{url: string, format?: string, parentURL?: string, filename: string}}
+ */
+function resolveForCJSWithHooks(specifier, parent, isMain) {
+  let parentURL;
+  if (parent) {
+    if (!parent[kURL] && parent.filename) {
+      parent[kURL] = convertCJSFilenameToURL(parent.filename);
+    }
+    parentURL = parent[kURL];
+  }
+
+  let defaultResolvedURL;
+  let defaultResolvedFilename;
+  function defaultResolve(specifier, context) {
+    // TODO(joyeecheung): parent and isMain should be part of context, then we
+    // no longer need to use a different defaultResolve for every resolution.
+    defaultResolvedFilename = Module._resolveFilename(specifier, parent, isMain, {
+      __proto__: null,
+      conditions: context.conditions,
+    }).toString();
+    defaultResolvedURL = convertCJSFilenameToURL(defaultResolvedFilename);
+    return { url: defaultResolvedURL };
+  }
+
+  const {
+    url, format,
+  } = resolveWithHooks(specifier, parentURL, /* importAttributes */undefined,
+                       getCjsConditions(), defaultResolve);
+
+  let filename;
+  if (url === defaultResolvedURL) {  // Not overridden, skip the re-conversion.
+    filename = defaultResolvedFilename;
+  } else {
+    filename = convertURLToCJSFilename(url);
+  }
+
+  return { __proto__: null, url, format, filename, parentURL };
+}
+
 /**
  * Load a module from cache if it exists, otherwise create a new module instance.
  * 1. If a module already exists in the cache: return its exports object.
@@ -1065,7 +1120,8 @@ Module._load = function(request, parent, isMain) {
     return module.exports;
   }
 
-  const filename = Module._resolveFilename(request, parent, isMain);
+  const { url, format, filename } = resolveForCJSWithHooks(request, parent, isMain);
+
   const cachedModule = Module._cache[filename];
   if (cachedModule !== undefined) {
     updateChildren(parent, cachedModule, true);
@@ -1110,6 +1166,10 @@ Module._load = function(request, parent, isMain) {
     reportModuleToWatchMode(filename);
     Module._cache[filename] = module;
     module[kIsCachedByESMLoader] = false;
+    // If there are resolve hooks, carry the context information into the
+    // load hooks for the module keyed by the (potentially customized) filename.
+    module[kURL] = url;
+    module[kFormat] = format;
   }
 
   if (parent !== undefined) {
@@ -1157,6 +1217,7 @@ Module._resolveFilename = function(request, parent, isMain, options) {
   if (BuiltinModule.normalizeRequirableId(request)) {
     return request;
   }
+  const conditions = (options?.conditions) || getCjsConditions();
 
   let paths;
 
@@ -1202,7 +1263,7 @@ Module._resolveFilename = function(request, parent, isMain, options) {
       try {
         const { packageImportsResolve } = require('internal/modules/esm/resolve');
         return finalizeEsmResolution(
-          packageImportsResolve(request, pathToFileURL(parentPath), getCjsConditions()),
+          packageImportsResolve(request, pathToFileURL(parentPath), conditions),
           parentPath,
           pkg.path,
         );
@@ -1217,7 +1278,7 @@ Module._resolveFilename = function(request, parent, isMain, options) {
 
   // Try module self resolution first
   const parentPath = trySelfParentPath(parent);
-  const selfResolved = trySelf(parentPath, request);
+  const selfResolved = trySelf(parentPath, request, conditions);
   if (selfResolved) {
     const cacheKey = request + '\x00' +
          (paths.length === 1 ? paths[0] : ArrayPrototypeJoin(paths, '\x00'));
@@ -1226,7 +1287,7 @@ Module._resolveFilename = function(request, parent, isMain, options) {
   }
 
   // Look up the filename first, since that's the cache key.
-  const filename = Module._findPath(request, paths, isMain);
+  const filename = Module._findPath(request, paths, isMain, conditions);
   if (filename) { return filename; }
   const requireStack = [];
   for (let cursor = parent;
@@ -1293,8 +1354,8 @@ Module.prototype.load = function(filename) {
   debug('load %j for module %j', filename, this.id);
 
   assert(!this.loaded);
-  this.filename = filename;
-  this.paths = Module._nodeModulePaths(path.dirname(filename));
+  this.filename ??= filename;
+  this.paths ??= Module._nodeModulePaths(path.dirname(filename));
 
   const extension = findLongestRegisteredExtension(filename);
 
@@ -1563,20 +1624,36 @@ Module.prototype._compile = function(content, filename, format) {
  * @returns {{source: string, format?: string}}
  */
 function loadSource(mod, filename, formatFromNode) {
-  if (formatFromNode !== undefined) {
+  if (mod[kFormat] === undefined) {
     mod[kFormat] = formatFromNode;
   }
-  const format = mod[kFormat];
+  // If the module was loaded before, just return.
+  if (mod[kModuleSource] !== undefined) {
+    return { source: mod[kModuleSource], format: mod[kFormat] };
+  }
 
-  let source = mod[kModuleSource];
-  if (source !== undefined) {
-    mod[kModuleSource] = undefined;
-  } else {
-    // TODO(joyeecheung): we can read a buffer instead to speed up
-    // compilation.
-    source = fs.readFileSync(filename, 'utf8');
+  if (mod[kURL] === undefined) {
+    mod[kURL] = convertCJSFilenameToURL(filename);
   }
-  return { source, format };
+  const url = mod[kURL];
+
+  const originalFormat = mod[kFormat];
+
+  function defaultLoad(url, context) {
+    // If the url is the same as the original one, save the conversion.
+    const newFilename = (url === mod[kURL]) ? filename : convertURLToCJSFilename(url);
+    const source = fs.readFileSync(newFilename, 'utf8');
+    return { source, format: originalFormat };
+  }
+
+  const loadResult = loadWithHooks(url, originalFormat, undefined, getCjsConditions(), defaultLoad);
+
+  // Reset the module properties with load hook results.
+  if (loadResult.format !== undefined) {
+    mod[kFormat] = loadResult.format;
+  }
+  mod[kModuleSource] = loadResult.source;
+  return { source: mod[kModuleSource], format: mod[kFormat] };
 }
 
 /**
@@ -1594,7 +1671,6 @@ function loadMTS(mod, filename) {
  * @param {Module} module CJS module instance
  * @param {string} filename The file path of the module
  */
-
 function loadCTS(module, filename) {
   const loadResult = loadSource(module, filename, 'commonjs-typescript');
   module._compile(loadResult.source, filename, loadResult.format);
@@ -1862,3 +1938,4 @@ ObjectDefineProperty(Module.prototype, 'constructor', {
 
 // Backwards compatibility
 Module.Module = Module;
+Module.registerHooks = registerHooks;