Version 3.3.0-177.0.dev

Merge 3f3e426 into dev

pkg/dart2wasm/lib/js/runtime_generator.dart

@@ -34,6 +34,7 @@ JSMethods _performJSInteropTransformations(
           InterfaceType(jsValueClass, staticInteropType.declaredNullability),
       additionalCoreLibraries: {
         '_js_helper',
+        '_js_string_convert',
         '_js_types',
         'convert',
         'js_interop',

sdk/lib/_internal/wasm/lib/convert_patch.dart

@@ -3,6 +3,8 @@
 // BSD-style license that can be found in the LICENSE file.
 
 import "dart:_internal" show patch, POWERS_OF_TEN, unsafeCast;
+import "dart:_js_string_convert";
+import "dart:_js_types";
 import "dart:_string";
 import "dart:_typed_data";
 import "dart:typed_data" show Uint8List, Uint16List;
@@ -1671,16 +1673,19 @@ class _Utf8Decoder {
     int end = RangeError.checkValidRange(start, maybeEnd, codeUnits.length);
     if (start == end) return "";
 
+    if (codeUnits is JSUint8ArrayImpl) {
+      JSStringImpl? decoded =
+          decodeUtf8JS(codeUnits, start, end, allowMalformed);
+      if (decoded != null) return decoded;
+    }
+
     final U8List bytes;
     if (codeUnits is U8List) {
       bytes = unsafeCast<U8List>(codeUnits);
     } else {
-      // TODO(omersa): Check if `codeUnits` is a JS array and call browser UTF8
-      // decoder here.
-      //
       // If we're passed a `List<int>` other than `U8List` or a JS typed array,
       // it means the performance is not too important. Convert the input to
-      // `U8List` to avoid shipping another UTF-8 decoder.
+      // `U8List` to avoid shipping another UTF-8 decoder for `List<int>`.
       final length = end - start;
       bytes = U8List(length);
       final u8listData = bytes.data;

sdk/lib/_internal/wasm/lib/js_string_convert.dart

@@ -0,0 +1,72 @@
+// Copyright (c) 2023, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+/// `dart:convert` UTF-8 decoding functions when the input is a JS typed array.
+library dart._js_string_convert;
+
+import "dart:_js_types";
+import 'dart:_js_helper' as js;
+import 'dart:_wasm';
+
+/// Implements `_Utf8Decoder.convertSingle` hook for JS array inputs. Does not
+/// do bounds checking.
+JSStringImpl? decodeUtf8JS(
+    JSUint8ArrayImpl codeUnits, int start, int end, bool allowMalformed) {
+  final length = end - start;
+  if (length >= _shortInputThreshold) {
+    final JSAny? decoder = allowMalformed ? _decoderNonFatal : _decoder;
+    if (decoder != null) {
+      final arrayRef = codeUnits.toJSArrayExternRef(start, length);
+      final textDecoderResult =
+          _useTextDecoder(externRefForJSAny(decoder), arrayRef);
+      if (textDecoderResult != null) {
+        return textDecoderResult;
+      }
+    }
+  }
+  return null;
+}
+
+// Always fall back to the Dart implementation for strings shorter than this
+// threshold, as there is a large, constant overhead for using `TextDecoder`.
+// TODO(omersa): This is copied from dart2js runtime, make sure the value is
+// right for dart2wasm.
+const int _shortInputThreshold = 15;
+
+JSStringImpl? _useTextDecoder(
+    WasmExternRef? decoder, WasmExternRef? codeUnits) {
+  // If the input is malformed, catch the exception and return `null` to fall
+  // back on unintercepted decoder. The fallback will either succeed in
+  // decoding, or report the problem better than `TextDecoder`.
+  try {
+    return JSStringImpl(js.JS<WasmExternRef?>(
+        '(decoder, codeUnits) => decoder.decode(codeUnits)',
+        decoder,
+        codeUnits));
+  } catch (e) {}
+  return null;
+}
+
+// TextDecoder is not defined on some browsers and on the stand-alone d8 and
+// jsshell engines. Use a lazy initializer to do feature detection once.
+//
+// Globals need to return boxed Dart values, so these return `JSAny?` instead
+// of `WasmExternRef?`.
+final JSAny? _decoder = () {
+  try {
+    return js
+        .JS<WasmExternRef>('() => new TextDecoder("utf-8", {fatal: true})')
+        .toJS;
+  } catch (e) {}
+  return null;
+}();
+
+final JSAny? _decoderNonFatal = () {
+  try {
+    return js
+        .JS<WasmExternRef>('() => new TextDecoder("utf-8", {fatal: false})')
+        .toJS;
+  } catch (e) {}
+  return null;
+}();

sdk/lib/_internal/wasm_js_compatibility/lib/convert_patch.dart

@@ -3,9 +3,10 @@
 // BSD-style license that can be found in the LICENSE file.
 
 import "dart:_internal" show ClassID, patch, POWERS_OF_TEN, unsafeCast;
+import "dart:_js_string_convert";
 import "dart:_js_types";
-import 'dart:_wasm';
 import 'dart:_js_helper' as js;
+import 'dart:_wasm';
 
 import "dart:typed_data" show Uint8List, Uint16List;
 
@@ -1480,32 +1481,16 @@ class _Utf8Decoder {
   @patch
   _Utf8Decoder(this.allowMalformed) : _state = beforeBom;
 
-  // Always fall back to the Dart implementation for strings shorter than this
-  // threshold, as there is a large, constant overhead for using TextDecoder.
-  // TODO(omersa): This is copied from dart2js runtime, make sure the value is
-  // right for dart2wasm.
-  static const int _shortInputThreshold = 15;
-
   @patch
   String convertSingle(List<int> codeUnits, int start, int? maybeEnd) {
     final codeUnitsLength = codeUnits.length;
     final end = RangeError.checkValidRange(start, maybeEnd, codeUnitsLength);
     if (start == end) return "";
 
-    final length = end - start;
-
     if (codeUnits is JSUint8ArrayImpl) {
-      if (length >= _shortInputThreshold) {
-        final JSAny? decoder = allowMalformed ? _decoderNonFatal : _decoder;
-        if (decoder != null) {
-          final arrayRef = codeUnits.toJSArrayExternRef(start, length);
-          final textDecoderResult =
-              _useTextDecoder(externRefForJSAny(decoder), arrayRef);
-          if (textDecoderResult != null) {
-            return textDecoderResult;
-          }
-        }
-      }
+      JSStringImpl? decoded =
+          decodeUtf8JS(codeUnits, start, end, allowMalformed);
+      if (decoded != null) return decoded;
     }
 
     return convertGeneral(codeUnits, start, maybeEnd, true);
@@ -1515,43 +1500,6 @@ class _Utf8Decoder {
   String convertChunked(List<int> codeUnits, int start, int? maybeEnd) {
     return convertGeneral(codeUnits, start, maybeEnd, false);
   }
-
-  static String? _useTextDecoder(
-      WasmExternRef? decoder, WasmExternRef? codeUnits) {
-    // If the input is malformed, catch the exception and return `null` to fall
-    // back on unintercepted decoder. The fallback will either succeed in
-    // decoding, or report the problem better than TextDecoder.
-    try {
-      return JSStringImpl(js.JS<WasmExternRef?>(
-          '(decoder, codeUnits) => decoder.decode(codeUnits)',
-          decoder,
-          codeUnits));
-    } catch (e) {}
-    return null;
-  }
-
-  // TextDecoder is not defined on some browsers and on the stand-alone d8 and
-  // jsshell engines. Use a lazy initializer to do feature detection once.
-  //
-  // Globls need to return boxed Dart values, so these return `JSAny?` instead
-  // of `WasmExternRef?`.
-  static final JSAny? _decoder = () {
-    try {
-      return js
-          .JS<WasmExternRef>('() => new TextDecoder("utf-8", {fatal: true})')
-          .toJS;
-    } catch (e) {}
-    return null;
-  }();
-
-  static final JSAny? _decoderNonFatal = () {
-    try {
-      return js
-          .JS<WasmExternRef>('() => new TextDecoder("utf-8", {fatal: false})')
-          .toJS;
-    } catch (e) {}
-    return null;
-  }();
 }
 
 double _parseDouble(String source, int start, int end) =>

sdk/lib/libraries.json

@@ -254,6 +254,9 @@
       "_js_helper": {
         "uri": "_internal/wasm/lib/js_helper.dart"
       },
+      "_js_string_convert": {
+        "uri": "_internal/wasm/lib/js_string_convert.dart"
+      },
       "_js_types": {
         "uri": "_internal/wasm/lib/js_types.dart"
       },

sdk/lib/libraries.yaml

@@ -212,6 +212,8 @@ wasm_common:
       uri: js/_js_annotations.dart
     _js_helper:
       uri: _internal/wasm/lib/js_helper.dart
+    _js_string_convert:
+      uri: _internal/wasm/lib/js_string_convert.dart
     _js_types:
       uri: _internal/wasm/lib/js_types.dart
     _object_helper:

tools/VERSION

@@ -27,5 +27,5 @@ CHANNEL dev
 MAJOR 3
 MINOR 3
 PATCH 0
-PRERELEASE 176
+PRERELEASE 177
 PRERELEASE_PATCH 0