Add support for the new importer API (#1522)

lib/src/importer/node_to_dart/async.dart

@@ -0,0 +1,56 @@
+// Copyright 2021 Google Inc. Use of this source code is governed by an
+// MIT-style license that can be found in the LICENSE file or at
+// https://opensource.org/licenses/MIT.
+
+import 'dart:async';
+
+import 'package:node_interop/js.dart';
+import 'package:node_interop/util.dart';
+
+import '../../node/importer.dart';
+import '../../node/url.dart';
+import '../../node/utils.dart';
+import '../../util/nullable.dart';
+import '../async.dart';
+import '../result.dart';
+
+/// A wrapper for a potentially-asynchronous JS API importer that exposes it as
+/// a Dart [AsyncImporter].
+class NodeToDartAsyncImporter extends AsyncImporter {
+  /// The wrapped canonicalize function.
+  final Object? Function(String, CanonicalizeOptions) _canonicalize;
+
+  /// The wrapped load function.
+  final Object? Function(JSUrl) _load;
+
+  NodeToDartAsyncImporter(this._canonicalize, this._load);
+
+  FutureOr<Uri?> canonicalize(Uri url) async {
+    var result = _canonicalize(
+        url.toString(), CanonicalizeOptions(fromImport: fromImport));
+    if (isPromise(result)) result = await promiseToFuture(result as Promise);
+    if (result == null) return null;
+
+    if (isJSUrl(result)) return jsToDartUrl(result as JSUrl);
+
+    jsThrow(JsError("The canonicalize() method must return a URL."));
+  }
+
+  FutureOr<ImporterResult?> load(Uri url) async {
+    var result = _load(dartToJSUrl(url));
+    if (isPromise(result)) result = await promiseToFuture(result as Promise);
+    if (result == null) return null;
+
+    result as NodeImporterResult;
+    var contents = result.contents;
+    var syntax = result.syntax;
+    if (contents == null || syntax == null) {
+      jsThrow(JsError("The load() function must return an object with contents "
+          "and syntax fields."));
+    }
+
+    return ImporterResult(contents,
+        syntax: parseSyntax(syntax),
+        sourceMapUrl: result.sourceMapUrl.andThen(jsToDartUrl));
+  }
+}

lib/src/importer/node_to_dart/async_file.dart

@@ -0,0 +1,80 @@
+// Copyright 2021 Google Inc. Use of this source code is governed by an
+// MIT-style license that can be found in the LICENSE file or at
+// https://opensource.org/licenses/MIT.
+
+import 'dart:async';
+
+import 'package:node_interop/js.dart';
+import 'package:node_interop/util.dart';
+import 'package:path/path.dart' as p;
+
+import '../../io.dart' as io;
+import '../../node/importer.dart';
+import '../../node/utils.dart';
+import '../../syntax.dart';
+import '../async.dart';
+import '../filesystem.dart';
+import '../result.dart';
+import '../utils.dart';
+
+/// A filesystem importer to use for most implementation details of
+/// [NodeToDartAsyncFileImporter].
+///
+/// This allows us to avoid duplicating logic between the two importers.
+final _filesystemImporter = FilesystemImporter('.');
+
+/// A wrapper for a potentially-asynchronous JS API file importer that exposes
+/// it as a Dart [AsyncImporter].
+class NodeToDartAsyncFileImporter extends AsyncImporter {
+  /// The wrapped `findFileUrl` function.
+  final Object? Function(String, CanonicalizeOptions) _findFileUrl;
+
+  /// A map from canonical URLs to the `sourceMapUrl`s associated with them.
+  final _sourceMapUrls = <Uri, Uri>{};
+
+  NodeToDartAsyncFileImporter(this._findFileUrl);
+
+  FutureOr<Uri?> canonicalize(Uri url) async {
+    if (url.scheme != 'file' && url.scheme != '') return null;
+
+    var result = _findFileUrl(
+        url.toString(), CanonicalizeOptions(fromImport: fromImport));
+    if (isPromise(result)) result = await promiseToFuture(result as Promise);
+    if (result == null) return null;
+
+    result as NodeFileImporterResult;
+    var dartUrl = result.url;
+    var sourceMapUrl = result.sourceMapUrl;
+    if (dartUrl == null) {
+      jsThrow(JsError(
+          "The findFileUrl() method must return an object a url field."));
+    }
+
+    var resultUrl = jsToDartUrl(dartUrl);
+    if (resultUrl.scheme != 'file') {
+      jsThrow(JsError(
+          'The findFileUrl() must return a URL with scheme file://, was '
+          '"$url".'));
+    }
+
+    var canonical = _filesystemImporter.canonicalize(resultUrl);
+    if (canonical == null) return null;
+    if (sourceMapUrl != null) {
+      _sourceMapUrls[canonical] = jsToDartUrl(sourceMapUrl);
+    }
+
+    return canonical;
+  }
+
+  ImporterResult? load(Uri url) {
+    var path = p.fromUri(url);
+    return ImporterResult(io.readFile(path),
+        sourceMapUrl: _sourceMapUrls[url] ?? url, syntax: Syntax.forPath(path));
+  }
+
+  DateTime modificationTime(Uri url) =>
+      _filesystemImporter.modificationTime(url);
+
+  bool couldCanonicalize(Uri url, Uri canonicalUrl) =>
+      _filesystemImporter.couldCanonicalize(url, canonicalUrl);
+}

lib/src/importer/node_to_dart/file.dart

@@ -0,0 +1,82 @@
+// Copyright 2021 Google Inc. Use of this source code is governed by an
+// MIT-style license that can be found in the LICENSE file or at
+// https://opensource.org/licenses/MIT.
+
+import 'package:node_interop/js.dart';
+import 'package:path/path.dart' as p;
+
+import '../../io.dart' as io;
+import '../../importer.dart';
+import '../../node/importer.dart';
+import '../../node/utils.dart';
+import '../../syntax.dart';
+import '../filesystem.dart';
+import '../result.dart';
+import '../utils.dart';
+
+/// A filesystem importer to use for most implementation details of
+/// [NodeToDartAsyncFileImporter].
+///
+/// This allows us to avoid duplicating logic between the two importers.
+final _filesystemImporter = FilesystemImporter('.');
+
+/// A wrapper for a potentially-asynchronous JS API file importer that exposes
+/// it as a Dart [AsyncImporter].
+class NodeToDartFileImporter extends Importer {
+  /// The wrapped `findFileUrl` function.
+  final Object? Function(String, CanonicalizeOptions) _findFileUrl;
+
+  /// A map from canonical URLs to the `sourceMapUrl`s associated with them.
+  final _sourceMapUrls = <Uri, Uri>{};
+
+  NodeToDartFileImporter(this._findFileUrl);
+
+  Uri? canonicalize(Uri url) {
+    if (url.scheme != 'file' && url.scheme != '') return null;
+
+    var result = _findFileUrl(
+        url.toString(), CanonicalizeOptions(fromImport: fromImport));
+    if (result == null) return null;
+
+    if (isPromise(result)) {
+      jsThrow(JsError(
+          "The canonicalize() function can't return a Promise for synchronous "
+          "compile functions."));
+    }
+
+    result as NodeFileImporterResult;
+    var dartUrl = result.url;
+    var sourceMapUrl = result.sourceMapUrl;
+    if (dartUrl == null) {
+      jsThrow(JsError(
+          "The findFileUrl() method must return an object a url field."));
+    }
+
+    var resultUrl = jsToDartUrl(dartUrl);
+    if (resultUrl.scheme != 'file') {
+      jsThrow(JsError(
+          'The findFileUrl() must return a URL with scheme file://, was '
+          '"$url".'));
+    }
+
+    var canonical = _filesystemImporter.canonicalize(resultUrl);
+    if (canonical == null) return null;
+    if (sourceMapUrl != null) {
+      _sourceMapUrls[canonical] = jsToDartUrl(sourceMapUrl);
+    }
+
+    return canonical;
+  }
+
+  ImporterResult? load(Uri url) {
+    var path = p.fromUri(url);
+    return ImporterResult(io.readFile(path),
+        sourceMapUrl: _sourceMapUrls[url] ?? url, syntax: Syntax.forPath(path));
+  }
+
+  DateTime modificationTime(Uri url) =>
+      _filesystemImporter.modificationTime(url);
+
+  bool couldCanonicalize(Uri url, Uri canonicalUrl) =>
+      _filesystemImporter.couldCanonicalize(url, canonicalUrl);
+}

lib/src/importer/node_to_dart/sync.dart

@@ -0,0 +1,62 @@
+// Copyright 2021 Google Inc. Use of this source code is governed by an
+// MIT-style license that can be found in the LICENSE file or at
+// https://opensource.org/licenses/MIT.
+
+import 'package:node_interop/js.dart';
+
+import '../../importer.dart';
+import '../../node/importer.dart';
+import '../../node/url.dart';
+import '../../node/utils.dart';
+import '../../util/nullable.dart';
+import '../result.dart';
+
+/// A wrapper for a synchronous JS API importer that exposes it as a Dart
+/// [Importer].
+class NodeToDartImporter extends Importer {
+  /// The wrapped canonicalize function.
+  final Object? Function(String, CanonicalizeOptions) _canonicalize;
+
+  /// The wrapped load function.
+  final Object? Function(JSUrl) _load;
+
+  NodeToDartImporter(this._canonicalize, this._load);
+
+  Uri? canonicalize(Uri url) {
+    var result = _canonicalize(
+        url.toString(), CanonicalizeOptions(fromImport: fromImport));
+    if (result == null) return null;
+    if (isJSUrl(result)) return jsToDartUrl(result as JSUrl);
+
+    if (isPromise(result)) {
+      jsThrow(JsError(
+          "The canonicalize() function can't return a Promise for synchronous "
+          "compile functions."));
+    } else {
+      jsThrow(JsError("The canonicalize() method must return a URL."));
+    }
+  }
+
+  ImporterResult? load(Uri url) {
+    var result = _load(dartToJSUrl(url));
+    if (result == null) return null;
+
+    if (isPromise(result)) {
+      jsThrow(JsError(
+          "The load() function can't return a Promise for synchronous compile "
+          "functions."));
+    }
+
+    result as NodeImporterResult;
+    var contents = result.contents;
+    var syntax = result.syntax;
+    if (contents == null || syntax == null) {
+      jsThrow(JsError("The load() function must return an object with contents "
+          "and syntax fields."));
+    }
+
+    return ImporterResult(contents,
+        syntax: parseSyntax(syntax),
+        sourceMapUrl: result.sourceMapUrl.andThen(jsToDartUrl));
+  }
+}