sdk/lib/_internal/wasm/lib/uri_patch.dart

// Copyright (c) 2022, 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.

// part of "core_patch.dart";

@pragma("wasm:import", "dart2wasm.isWindows")
external bool _isWindowsRaw();

@pragma("wasm:import", "dart2wasm.getCurrentUri")
external String? _currentUriRaw();

@patch
class Uri {
  @patch
  static Uri get base {
    String? currentUri = _currentUriRaw();
    if (currentUri != null) {
      return Uri.parse(currentUri);
    }
    throw UnsupportedError("'Uri.base' is not supported");
  }
}

@patch
class _Uri {
  @patch
  static bool get _isWindows => _isWindowsCached;

  static final bool _isWindowsCached = _isWindowsRaw();

  // Matches a String that _uriEncodes to itself regardless of the kind of
  // component.  This corresponds to [_unreservedTable], i.e. characters that
  // are not encoded by any encoding table.
  static final RegExp _needsNoEncoding = RegExp(r'^[\-\.0-9A-Z_a-z~]*$');

  /**
   * This is the internal implementation of JavaScript's encodeURI function.
   * It encodes all characters in the string [text] except for those
   * that appear in [canonicalTable], and returns the escaped string.
   */
  @patch
  static String _uriEncode(List<int> canonicalTable, String text,
      Encoding encoding, bool spaceToPlus) {
    if (identical(encoding, utf8) && _needsNoEncoding.hasMatch(text)) {
      return text;
    }

    // Encode the string into bytes then generate an ASCII only string
    // by percent encoding selected bytes.
    StringBuffer result = StringBuffer('');
    var bytes = encoding.encode(text);
    for (int i = 0; i < bytes.length; i++) {
      int byte = bytes[i];
      if (byte < 128 &&
          ((canonicalTable[byte >> 4] & (1 << (byte & 0x0f))) != 0)) {
        result.writeCharCode(byte);
      } else if (spaceToPlus && byte == _SPACE) {
        result.write('+');
      } else {
        const String hexDigits = '0123456789ABCDEF';
        result.write('%');
        result.write(hexDigits[(byte >> 4) & 0x0f]);
        result.write(hexDigits[byte & 0x0f]);
      }
    }
    return result.toString();
  }
}