void _writeFlutterApi()

in packages/pigeon/lib/dart_generator.dart [236:358]
122 lines of code
17 McCabe index (conditional complexity)

void _writeFlutterApi(
  DartOptions opt,
  Indent indent,
  Api api,
  Root root, {
  String Function(Method)? channelNameFunc,
  bool isMockHandler = false,
}) {
  assert(api.location == ApiLocation.flutter);
  final String codecName = _getCodecName(api);
  _writeCodec(indent, codecName, api, root);
  final String nullTag = opt.isNullSafe ? '?' : '';
  final String unwrapOperator = opt.isNullSafe ? '!' : '';
  indent.write('abstract class ${api.name} ');
  indent.scoped('{', '}', () {
    indent.writeln('static const MessageCodec<Object?> codec = $codecName();');
    indent.addln('');
    for (final Method func in api.methods) {
      final bool isAsync = func.isAsynchronous;
      final String returnType = isAsync
          ? 'Future<${_addGenericTypes(func.returnType, nullTag)}>'
          : _addGenericTypes(func.returnType, nullTag);
      final String argSignature = _getMethodArgumentsSignature(
        func,
        _getArgumentName,
        nullTag,
      );
      indent.writeln('$returnType ${func.name}($argSignature);');
    }
    indent.write(
        'static void setup(${api.name}$nullTag api, {BinaryMessenger$nullTag binaryMessenger}) ');
    indent.scoped('{', '}', () {
      for (final Method func in api.methods) {
        indent.write('');
        indent.scoped('{', '}', () {
          indent.writeln(
            'final BasicMessageChannel<Object$nullTag> channel = BasicMessageChannel<Object$nullTag>(',
          );
          final String channelName = channelNameFunc == null
              ? makeChannelName(api, func)
              : channelNameFunc(func);
          indent.nest(2, () {
            indent.writeln(
              '\'$channelName\', codec, binaryMessenger: binaryMessenger);',
            );
          });
          final String messageHandlerSetter =
              isMockHandler ? 'setMockMessageHandler' : 'setMessageHandler';
          indent.write('if (api == null) ');
          indent.scoped('{', '}', () {
            indent.writeln('channel.$messageHandlerSetter(null);');
          }, addTrailingNewline: false);
          indent.add(' else ');
          indent.scoped('{', '}', () {
            indent.write(
              'channel.$messageHandlerSetter((Object$nullTag message) async ',
            );
            indent.scoped('{', '});', () {
              final String returnType =
                  _addGenericTypes(func.returnType, nullTag);
              final bool isAsync = func.isAsynchronous;
              final String emptyReturnStatement = isMockHandler
                  ? 'return <Object$nullTag, Object$nullTag>{};'
                  : func.returnType.isVoid
                      ? 'return;'
                      : 'return null;';
              String call;
              if (func.arguments.isEmpty) {
                indent.writeln('// ignore message');
                call = 'api.${func.name}()';
              } else {
                indent.writeln(
                  'assert(message != null, \'Argument for $channelName was null.\');',
                );
                const String argsArray = 'args';
                indent.writeln(
                    'final List<Object$nullTag> $argsArray = (message as List<Object$nullTag>$nullTag)$unwrapOperator;');
                String argNameFunc(int index, NamedType type) =>
                    _getSafeArgumentName(index, type);
                enumerate(func.arguments, (int count, NamedType arg) {
                  final String argType = _addGenericTypes(arg.type, nullTag);
                  final String argName = argNameFunc(count, arg);
                  final String genericArgType =
                      _makeGenericTypeArguments(arg.type, nullTag);
                  final String castCall =
                      _makeGenericCastCall(arg.type, nullTag);

                  indent.writeln(
                      'final $argType$nullTag $argName = ($argsArray[$count] as $genericArgType$nullTag)${castCall.isEmpty ? '' : '$nullTag$castCall'};');
                  indent.writeln(
                      'assert($argName != null, \'Argument for $channelName was null, expected non-null $argType.\');');
                });
                final Iterable<String> argNames =
                    indexMap(func.arguments, argNameFunc);
                call =
                    'api.${func.name}(${argNames.map<String>((String x) => '$x$unwrapOperator').join(', ')})';
              }
              if (func.returnType.isVoid) {
                if (isAsync) {
                  indent.writeln('await $call;');
                } else {
                  indent.writeln('$call;');
                }
                indent.writeln(emptyReturnStatement);
              } else {
                if (isAsync) {
                  indent.writeln('final $returnType output = await $call;');
                } else {
                  indent.writeln('final $returnType output = $call;');
                }
                const String returnExpression = 'output';
                final String returnStatement = isMockHandler
                    ? 'return <Object$nullTag, Object$nullTag>{\'${Keys.result}\': $returnExpression};'
                    : 'return $returnExpression;';
                indent.writeln(returnStatement);
              }
            });
          });
        });
      }
    });
  });
}