A Dart package for parsing, analyzing, and producing Windows Metadata (.winmd) files, based on the ECMA-335 standard.

This package offers both low-level primitives and high-level abstractions for inspecting and generating Windows Metadata (.winmd) files. It is a vital component of Dart-based Windows interop tooling — powering packages like win32.

Key Features

• Parse .winmd files into rich, strongly-typed Dart object models
• Query type definitions, methods, fields, and more across multiple metadata sources
• Perform fast, namespace-agnostic symbol resolution
• Merge multiple .winmd files into a single, unified file
• Generate your own .winmd files programmatically
• Works on Windows, Linux, and macOS

Usage

A basic example demonstrating how to load and inspect WinRT metadata from a .winmd file:

import 'dart:io' as io;

import 'package:winmd/winmd.dart';

void main() {
  // Load WinRT metadata from a local .winmd file.
  const winmdPath = r'C:\WINDOWS\System32\WinMetadata\Windows.Storage.winmd';
  final bytes = io.File(winmdPath).readAsBytesSync();
  final reader = MetadataReader.read(bytes);
  final index = MetadataIndex.fromReader(reader);

  // Optional: Use MetadataLookup for efficient type resolution by name.
  // This is especially helpful when the namespace of the target type is
  // unknown.
  final metadata = MetadataLookup(index);

  // Lookup a WinRT class (e.g., StorageFile) and list its public methods.
  final storageFile = metadata.findSingleTypeByName('StorageFile');
  print('WinRT class "${storageFile.name}" has the following methods:');
  for (final method in storageFile.methods) {
    print('  ${method.name}');
  }
  print('');

  // Lookup a WinRT enum (e.g., FileAttributes) and display its members.
  final enumType = metadata.findSingleTypeByName('FileAttributes');
  print('WinRT enum "${enumType.name}" has the following fields:');

  // The first field represents the underlying integral type (e.g., Int32).
  final underlyingType = enumType.fields.first;
  print('  ${underlyingType.name} = ${underlyingType.signature.type}');

  // Subsequent fields are named values within the enum.
  for (final field in enumType.fields.skip(1)) {
    print('  ${field.name} = ${field.constant?.value}');
  }
}

More examples can be found in the example subdirectory.

Feature requests and bugs

Please file feature requests and bugs at the issue tracker.