[Package Importer] Dart Implementation (sass#2130)

Co-authored-by: Jonny Gerig Meyer <jonny@oddbird.net>

lib/src/async_compile.dart

@@ -26,7 +26,8 @@ import 'visitor/serialize.dart';
 /// Like [compileAsync] in `lib/sass.dart`, but provides more options to support
 /// the node-sass compatible API and the executable.
 ///
-/// At most one of `importCache` and `nodeImporter` may be provided at once.
+/// If both `importCache` and `nodeImporter` are provided, the importers in
+/// `importCache` will be evaluated before `nodeImporter`.
 Future<CompileResult> compileAsync(String path,
     {Syntax? syntax,
     Logger? logger,
@@ -56,7 +57,7 @@ Future<CompileResult> compileAsync(String path,
       (syntax == null || syntax == Syntax.forPath(path))) {
     importCache ??= AsyncImportCache.none(logger: logger);
     stylesheet = (await importCache.importCanonical(
-        FilesystemImporter('.'), p.toUri(canonicalize(path)),
+        FilesystemImporter.cwd, p.toUri(canonicalize(path)),
         originalUrl: p.toUri(path)))!;
   } else {
     stylesheet = Stylesheet.parse(
@@ -69,7 +70,7 @@ Future<CompileResult> compileAsync(String path,
       logger,
       importCache,
       nodeImporter,
-      FilesystemImporter('.'),
+      FilesystemImporter.cwd,
       functions,
       style,
       useSpaces,
@@ -121,7 +122,7 @@ Future<CompileResult> compileStringAsync(String source,
       logger,
       importCache,
       nodeImporter,
-      importer ?? (isBrowser ? NoOpImporter() : FilesystemImporter('.')),
+      importer ?? (isBrowser ? NoOpImporter() : FilesystemImporter.cwd),
       functions,
       style,
       useSpaces,

lib/src/async_import_cache.dart

@@ -104,6 +104,12 @@ final class AsyncImportCache {
       : _importers = const [],
         _logger = logger ?? const Logger.stderr();
 
+  /// Creates an import cache without any globally-available importers, and only
+  /// the passed in importers.
+  AsyncImportCache.only(Iterable<AsyncImporter> importers, {Logger? logger})
+      : _importers = List.unmodifiable(importers),
+        _logger = logger ?? const Logger.stderr();
+
   /// Converts the user's [importers], [loadPaths], and [packageConfig]
   /// options into a single list of importers.
   static List<AsyncImporter> _toImporters(Iterable<AsyncImporter>? importers,

lib/src/compile.dart

@@ -5,7 +5,7 @@
 // DO NOT EDIT. This file was generated from async_compile.dart.
 // See tool/grind/synchronize.dart for details.
 //
-// Checksum: 5178e366228bde7854df12221393857bb3022628
+// Checksum: a9421a2975e79ad591ae32474cd076e1379d0e75
 //
 // ignore_for_file: unused_import
 
@@ -35,7 +35,8 @@ import 'visitor/serialize.dart';
 /// Like [compile] in `lib/sass.dart`, but provides more options to support
 /// the node-sass compatible API and the executable.
 ///
-/// At most one of `importCache` and `nodeImporter` may be provided at once.
+/// If both `importCache` and `nodeImporter` are provided, the importers in
+/// `importCache` will be evaluated before `nodeImporter`.
 CompileResult compile(String path,
     {Syntax? syntax,
     Logger? logger,
@@ -65,7 +66,7 @@ CompileResult compile(String path,
       (syntax == null || syntax == Syntax.forPath(path))) {
     importCache ??= ImportCache.none(logger: logger);
     stylesheet = importCache.importCanonical(
-        FilesystemImporter('.'), p.toUri(canonicalize(path)),
+        FilesystemImporter.cwd, p.toUri(canonicalize(path)),
         originalUrl: p.toUri(path))!;
   } else {
     stylesheet = Stylesheet.parse(
@@ -78,7 +79,7 @@ CompileResult compile(String path,
       logger,
       importCache,
       nodeImporter,
-      FilesystemImporter('.'),
+      FilesystemImporter.cwd,
       functions,
       style,
       useSpaces,
@@ -130,7 +131,7 @@ CompileResult compileString(String source,
       logger,
       importCache,
       nodeImporter,
-      importer ?? (isBrowser ? NoOpImporter() : FilesystemImporter('.')),
+      importer ?? (isBrowser ? NoOpImporter() : FilesystemImporter.cwd),
       functions,
       style,
       useSpaces,

lib/src/embedded/compilation_dispatcher.dart

@@ -11,6 +11,7 @@ import 'package:native_synchronization/mailbox.dart';
 import 'package:path/path.dart' as p;
 import 'package:protobuf/protobuf.dart';
 import 'package:sass/sass.dart' as sass;
+import 'package:sass/src/importer/node_package.dart' as npi;
 
 import '../logger.dart';
 import '../value/function.dart';
@@ -226,6 +227,10 @@ final class CompilationDispatcher {
       case InboundMessage_CompileRequest_Importer_Importer.notSet:
         _checkNoNonCanonicalScheme(importer);
         return null;
+
+      case InboundMessage_CompileRequest_Importer_Importer.nodePackageImporter:
+        return npi.NodePackageImporter(
+            importer.nodePackageImporter.entryPointDirectory);
     }
   }
 

lib/src/embedded/importer/file.dart

@@ -6,12 +6,6 @@ import '../../importer.dart';
 import '../embedded_sass.pb.dart' hide SourceSpan;
 import 'base.dart';
 
-/// A filesystem importer to use for most implementation details of
-/// [FileImporter].
-///
-/// This allows us to avoid duplicating logic between the two importers.
-final _filesystemImporter = FilesystemImporter('.');
-
 /// An importer that asks the host to resolve imports in a simplified,
 /// file-system-centric way.
 final class FileImporter extends ImporterBase {
@@ -21,7 +15,7 @@ final class FileImporter extends ImporterBase {
   FileImporter(super.dispatcher, this._importerId);
 
   Uri? canonicalize(Uri url) {
-    if (url.scheme == 'file') return _filesystemImporter.canonicalize(url);
+    if (url.scheme == 'file') return FilesystemImporter.cwd.canonicalize(url);
 
     var request = OutboundMessage_FileImportRequest()
       ..importerId = _importerId
@@ -39,7 +33,7 @@ final class FileImporter extends ImporterBase {
           throw 'The file importer must return a file: URL, was "$url"';
         }
 
-        return _filesystemImporter.canonicalize(url);
+        return FilesystemImporter.cwd.canonicalize(url);
 
       case InboundMessage_FileImportResponse_Result.error:
         throw response.error;
@@ -49,7 +43,7 @@ final class FileImporter extends ImporterBase {
     }
   }
 
-  ImporterResult? load(Uri url) => _filesystemImporter.load(url);
+  ImporterResult? load(Uri url) => FilesystemImporter.cwd.load(url);
 
   bool isNonCanonicalScheme(String scheme) => scheme != 'file';
 

lib/src/executable/compile_stylesheet.dart

@@ -69,7 +69,7 @@ Future<(int, String, String?)?> compileStylesheet(ExecutableOptions options,
 Future<void> _compileStylesheetWithoutErrorHandling(ExecutableOptions options,
     StylesheetGraph graph, String? source, String? destination,
     {bool ifModified = false}) async {
-  var importer = FilesystemImporter('.');
+  var importer = FilesystemImporter.cwd;
   if (ifModified) {
     try {
       if (source != null &&
@@ -103,7 +103,7 @@ Future<void> _compileStylesheetWithoutErrorHandling(ExecutableOptions options,
               syntax: syntax,
               logger: options.logger,
               importCache: importCache,
-              importer: FilesystemImporter('.'),
+              importer: FilesystemImporter.cwd,
               style: options.style,
               quietDeps: options.quietDeps,
               verbose: options.verbose,
@@ -128,7 +128,7 @@ Future<void> _compileStylesheetWithoutErrorHandling(ExecutableOptions options,
               syntax: syntax,
               logger: options.logger,
               importCache: graph.importCache,
-              importer: FilesystemImporter('.'),
+              importer: FilesystemImporter.cwd,
               style: options.style,
               quietDeps: options.quietDeps,
               verbose: options.verbose,

lib/src/executable/repl.dart

@@ -22,7 +22,7 @@ Future<void> repl(ExecutableOptions options) async {
   var repl = Repl(prompt: '>> ');
   var logger = TrackingLogger(options.logger);
   var evaluator = Evaluator(
-      importer: FilesystemImporter('.'),
+      importer: FilesystemImporter.cwd,
       importCache: ImportCache(loadPaths: options.loadPaths, logger: logger),
       logger: logger);
   await for (String line in repl.runAsync()) {

lib/src/executable/watch.dart

@@ -39,7 +39,7 @@ Future<void> watch(ExecutableOptions options, StylesheetGraph graph) async {
   var sourcesToDestinations = _sourcesToDestinations(options);
   for (var source in sourcesToDestinations.keys) {
     graph.addCanonical(
-        FilesystemImporter('.'), p.toUri(canonicalize(source)), p.toUri(source),
+        FilesystemImporter.cwd, p.toUri(canonicalize(source)), p.toUri(source),
         recanonicalize: false);
   }
   var success = await compileStylesheets(options, graph, sourcesToDestinations,
@@ -130,7 +130,7 @@ final class _Watcher {
         await compileStylesheets(_options, _graph, {path: destination},
             ifModified: true);
     var downstream = _graph.addCanonical(
-        FilesystemImporter('.'), _canonicalize(path), p.toUri(path));
+        FilesystemImporter.cwd, _canonicalize(path), p.toUri(path));
     return await _recompileDownstream(downstream) && success;
   }
 
@@ -144,7 +144,7 @@ final class _Watcher {
       if (_destinationFor(path) case var destination?) _delete(destination);
     }
 
-    var downstream = _graph.remove(FilesystemImporter('.'), url);
+    var downstream = _graph.remove(FilesystemImporter.cwd, url);
     return await _recompileDownstream(downstream);
   }
 

lib/src/import_cache.dart

@@ -5,7 +5,7 @@
 // DO NOT EDIT. This file was generated from async_import_cache.dart.
 // See tool/grind/synchronize.dart for details.
 //
-// Checksum: 342e907cf10e1dd80d7045fc32db43c74376654e
+// Checksum: d157b83599dbc07a80ac6cb5ffdf5dde03b60376
 //
 // ignore_for_file: unused_import
 
@@ -106,6 +106,12 @@ final class ImportCache {
       : _importers = const [],
         _logger = logger ?? const Logger.stderr();
 
+  /// Creates an import cache without any globally-available importers, and only
+  /// the passed in importers.
+  ImportCache.only(Iterable<Importer> importers, {Logger? logger})
+      : _importers = List.unmodifiable(importers),
+        _logger = logger ?? const Logger.stderr();
+
   /// Converts the user's [importers], [loadPaths], and [packageConfig]
   /// options into a single list of importers.
   static List<Importer> _toImporters(Iterable<Importer>? importers,

lib/src/importer/filesystem.dart

@@ -22,6 +22,9 @@ class FilesystemImporter extends Importer {
   /// Creates an importer that loads files relative to [loadPath].
   FilesystemImporter(String loadPath) : _loadPath = p.absolute(loadPath);
 
+  /// Creates an importer relative to the current working directory.
+  static final cwd = FilesystemImporter('.');
+
   Uri? canonicalize(Uri url) {
     if (url.scheme != 'file' && url.scheme != '') return null;
     return resolveImportPath(p.join(_loadPath, p.fromUri(url)))

lib/src/importer/js_to_dart/async_file.dart

@@ -17,12 +17,6 @@ import '../filesystem.dart';
 import '../result.dart';
 import '../utils.dart';
 
-/// A filesystem importer to use for most implementation details of
-/// [JSToDartAsyncFileImporter].
-///
-/// 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].
 final class JSToDartAsyncFileImporter extends AsyncImporter {
@@ -32,7 +26,7 @@ final class JSToDartAsyncFileImporter extends AsyncImporter {
   JSToDartAsyncFileImporter(this._findFileUrl);
 
   FutureOr<Uri?> canonicalize(Uri url) async {
-    if (url.scheme == 'file') return _filesystemImporter.canonicalize(url);
+    if (url.scheme == 'file') return FilesystemImporter.cwd.canonicalize(url);
 
     var result = wrapJSExceptions(() => _findFileUrl(
         url.toString(),
@@ -52,16 +46,16 @@ final class JSToDartAsyncFileImporter extends AsyncImporter {
           '"$url".'));
     }
 
-    return _filesystemImporter.canonicalize(resultUrl);
+    return FilesystemImporter.cwd.canonicalize(resultUrl);
   }
 
-  ImporterResult? load(Uri url) => _filesystemImporter.load(url);
+  ImporterResult? load(Uri url) => FilesystemImporter.cwd.load(url);
 
   DateTime modificationTime(Uri url) =>
-      _filesystemImporter.modificationTime(url);
+      FilesystemImporter.cwd.modificationTime(url);
 
   bool couldCanonicalize(Uri url, Uri canonicalUrl) =>
-      _filesystemImporter.couldCanonicalize(url, canonicalUrl);
+      FilesystemImporter.cwd.couldCanonicalize(url, canonicalUrl);
 
   bool isNonCanonicalScheme(String scheme) => scheme != 'file';
 }

lib/src/importer/js_to_dart/file.dart

@@ -12,12 +12,6 @@ import '../../js/utils.dart';
 import '../../util/nullable.dart';
 import '../utils.dart';
 
-/// A filesystem importer to use for most implementation details of
-/// [JSToDartAsyncFileImporter].
-///
-/// 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].
 final class JSToDartFileImporter extends Importer {
@@ -27,7 +21,7 @@ final class JSToDartFileImporter extends Importer {
   JSToDartFileImporter(this._findFileUrl);
 
   Uri? canonicalize(Uri url) {
-    if (url.scheme == 'file') return _filesystemImporter.canonicalize(url);
+    if (url.scheme == 'file') return FilesystemImporter.cwd.canonicalize(url);
 
     var result = wrapJSExceptions(() => _findFileUrl(
         url.toString(),
@@ -51,16 +45,16 @@ final class JSToDartFileImporter extends Importer {
           '"$url".'));
     }
 
-    return _filesystemImporter.canonicalize(resultUrl);
+    return FilesystemImporter.cwd.canonicalize(resultUrl);
   }
 
-  ImporterResult? load(Uri url) => _filesystemImporter.load(url);
+  ImporterResult? load(Uri url) => FilesystemImporter.cwd.load(url);
 
   DateTime modificationTime(Uri url) =>
-      _filesystemImporter.modificationTime(url);
+      FilesystemImporter.cwd.modificationTime(url);
 
   bool couldCanonicalize(Uri url, Uri canonicalUrl) =>
-      _filesystemImporter.couldCanonicalize(url, canonicalUrl);
+      FilesystemImporter.cwd.couldCanonicalize(url, canonicalUrl);
 
   bool isNonCanonicalScheme(String scheme) => scheme != 'file';
 }