feat(share_plus)!: Native share UI for Windows

.github/workflows/share_plus.yaml

@@ -165,7 +165,6 @@ jobs:
         run: ./.github/workflows/scripts/build-examples.sh windows ./lib/main.dart
 
   windows_integration_test:
-    if: false  # TODO: enable this if it is possible to register a mailto protocol handler on github hosted runners
     runs-on: windows-latest
     timeout-minutes: 30
     steps:

packages/share_plus/share_plus/example/lib/main.dart

@@ -4,11 +4,14 @@
 
 // ignore_for_file: public_member_api_docs
 
+import 'dart:io';
 import 'package:flutter/material.dart';
-import 'package:image_picker/image_picker.dart';
 import 'package:share_plus/share_plus.dart';
+import 'package:image_picker/image_picker.dart';
 
 import 'image_previews.dart';
+import 'utils/file_picker_win.dart'
+    if (dart.library.html) 'utils/file_picker_web.dart';
 
 void main() {
   runApp(const DemoApp());
@@ -67,15 +70,27 @@ class DemoAppState extends State<DemoApp> {
                     leading: const Icon(Icons.add),
                     title: const Text('Add image'),
                     onTap: () async {
-                      final imagePicker = ImagePicker();
-                      final pickedFile = await imagePicker.pickImage(
-                        source: ImageSource.gallery,
-                      );
-                      if (pickedFile != null) {
-                        setState(() {
-                          imagePaths.add(pickedFile.path);
-                          imageNames.add(pickedFile.name);
-                        });
+                      // Using `package:image_picker` to get image from gallery.
+                      if (Platform.isWindows) {
+                        // Using `package:filepicker_windows` on Windows, since `package:image_picker` is not supported.
+                        final path = await pickFile();
+                        if (path != null) {
+                          setState(() {
+                            imagePaths.add(path);
+                            imageNames.add(path.split('\\').last);
+                          });
+                        }
+                      } else {
+                        final imagePicker = ImagePicker();
+                        final pickedFile = await imagePicker.pickImage(
+                          source: ImageSource.gallery,
+                        );
+                        if (pickedFile != null) {
+                          setState(() {
+                            imagePaths.add(pickedFile.path);
+                            imageNames.add(pickedFile.name);
+                          });
+                        }
                       }
                     },
                   ),

packages/share_plus/share_plus/example/lib/utils/file_picker_web.dart

@@ -0,0 +1,4 @@
+/// Dummy implementation for non `dart.library.io` platforms.
+Future<String?> pickFile() async {
+  throw UnimplementedError();
+}

packages/share_plus/share_plus/example/lib/utils/file_picker_win.dart

@@ -0,0 +1,9 @@
+import 'package:filepicker_windows/filepicker_windows.dart';
+
+/// Picks a file from the file system on Windows & returns it's path as [String].
+Future<String?> pickFile() async {
+  final picker = OpenFilePicker()
+    ..filterSpecification = {'Images': '*.jpg;*.jpeg;*.png;*.gif'};
+  final result = picker.getFile();
+  return result?.path;
+}

packages/share_plus/share_plus/example/pubspec.yaml

@@ -7,6 +7,7 @@ dependencies:
   share_plus:
     path: ../
   image_picker: ^0.8.4
+  filepicker_windows: ^2.0.2
 
 dependency_overrides:
   share_plus_linux:

packages/share_plus/share_plus_windows/.clang-format

@@ -0,0 +1,12 @@
+# Defines the Chromium style for automatic reformatting.
+# http://clang.llvm.org/docs/ClangFormatStyleOptions.html
+BasedOnStyle: Chromium
+# This defaults to 'Auto'. Explicitly set it for a while, so that
+# 'vector<vector<int> >' in existing files gets formatted to
+# 'vector<vector<int>>'. ('Auto' means that clang-format will only use
+# 'int>>' if the file already contains at least one such instance.)
+Standard: Cpp11
+SortIncludes: true
+---
+Language: ObjC
+ColumnLimit: 100

packages/share_plus/share_plus_windows/lib/share_plus_windows.dart

@@ -3,14 +3,19 @@ library share_plus_windows;
 
 import 'dart:ui';
 
+import 'package:share_plus_windows/src/version_helper.dart';
 import 'package:url_launcher/url_launcher.dart';
 import 'package:share_plus_platform_interface/share_plus_platform_interface.dart';
 
-/// The Windows implementation of SharePlatform.
+/// The fallback Windows implementation of [SharePlatform], for older Windows versions.
+///
 class ShareWindows extends SharePlatform {
-  /// Register this dart class as the platform implementation for linux
+  /// If the modern Share UI i.e. `DataTransferManager` is not available, then use this Dart class instead of platform specific implementation.
+  ///
   static void registerWith() {
-    SharePlatform.instance = ShareWindows();
+    if (!VersionHelper.instance.isWindows10RS5OrGreater) {
+      SharePlatform.instance = ShareWindows();
+    }
   }
 
   /// Share text.

packages/share_plus/share_plus_windows/lib/src/version_helper.dart

@@ -0,0 +1,43 @@
+import 'dart:io';
+import 'dart:ffi';
+import 'package:ffi/ffi.dart';
+import 'package:win32/win32.dart';
+
+class VersionHelper {
+  static VersionHelper instance = VersionHelper._();
+
+  /// Whether the current OS is Windows 10 Redstone 5 or later.
+  /// This is used to determine whether the modern Share UI i.e. `DataTransferManager` is available or not.
+  ///
+  /// References: https://en.wikipedia.org/wiki/Windows_10_version_history
+  ///             https://docs.microsoft.com/en-us/windows/win32/api/winnt/ns-winnt-osversioninfoexa
+  ///
+  bool isWindows10RS5OrGreater = false;
+
+  static const int _kWindows10RS5BuildNumber = 17763;
+
+  VersionHelper._() {
+    if (Platform.isWindows) {
+      final pointer = calloc<OSVERSIONINFOEX>();
+      pointer.ref
+        ..dwOSVersionInfoSize = sizeOf<OSVERSIONINFOEX>()
+        ..dwBuildNumber = 0
+        ..dwMajorVersion = 0
+        ..dwMinorVersion = 0
+        ..dwPlatformId = 0
+        ..szCSDVersion = ''
+        ..wServicePackMajor = 0
+        ..wServicePackMinor = 0
+        ..wSuiteMask = 0
+        ..wProductType = 0
+        ..wReserved = 0;
+      final rtlGetVersion = DynamicLibrary.open('ntdll.dll').lookupFunction<
+          Void Function(Pointer<OSVERSIONINFOEX>),
+          void Function(Pointer<OSVERSIONINFOEX>)>('RtlGetVersion');
+      rtlGetVersion(pointer);
+      isWindows10RS5OrGreater =
+          pointer.ref.dwBuildNumber >= _kWindows10RS5BuildNumber;
+      calloc.free(pointer);
+    }
+  }
+}

packages/share_plus/share_plus_windows/pubspec.yaml

@@ -14,6 +14,8 @@ dependencies:
     sdk: flutter
   meta: ^1.7.0
   url_launcher: ^6.1.2
+  ffi: ^2.0.1
+  win32: ^2.3.8
 
 dev_dependencies:
   flutter_test:
@@ -23,8 +25,6 @@ dev_dependencies:
 
 flutter:
   plugin:
-    implements: share_plus
     platforms:
       windows:
-        dartPluginClass: ShareWindows
-        pluginClass: none
+        pluginClass: SharePlusWindowsPluginCApi

packages/share_plus/share_plus_windows/test/share_plus_windows_test.dart

@@ -1,40 +1,72 @@
 import 'package:flutter_test/flutter_test.dart';
-import 'package:share_plus_platform_interface/share_plus_platform_interface.dart';
 import 'package:share_plus_windows/share_plus_windows.dart';
+import 'package:share_plus_windows/src/version_helper.dart';
+import 'package:share_plus_platform_interface/share_plus_platform_interface.dart';
+import 'package:share_plus_platform_interface/method_channel/method_channel_share.dart';
+
 import 'package:url_launcher_platform_interface/url_launcher_platform_interface.dart';
 import 'package:url_launcher_platform_interface/link.dart';
 
 void main() {
-  test('registered instance', () {
-    ShareWindows.registerWith();
-    expect(SharePlatform.instance, isA<ShareWindows>());
-  });
-  test('url encoding is correct for &', () async {
-    final mock = MockUrlLauncherPlatform();
-    UrlLauncherPlatform.instance = mock;
+  test(
+    'registered instance',
+    () {
+      ShareWindows.registerWith();
+      expect(SharePlatform.instance, isA<ShareWindows>());
+    },
+    skip: VersionHelper.instance.isWindows10RS5OrGreater,
+  );
+
+  test(
+    'registered instance',
+    () {
+      ShareWindows.registerWith();
+      expect(SharePlatform.instance, isA<MethodChannelShare>());
+    },
+    skip: !VersionHelper.instance.isWindows10RS5OrGreater,
+  );
+
+  // These tests are only valid on Windows versions lower than 10.0.17763.0.
+
+  test(
+    'url encoding is correct for &',
+    () async {
+      final mock = MockUrlLauncherPlatform();
+      UrlLauncherPlatform.instance = mock;
 
-    await ShareWindows().share('foo&bar', subject: 'bar&foo');
+      await ShareWindows().share('foo&bar', subject: 'bar&foo');
 
-    expect(mock.url, 'mailto:?subject=bar%26foo&body=foo%26bar');
-  });
+      expect(mock.url, 'mailto:?subject=bar%26foo&body=foo%26bar');
+    },
+    skip: VersionHelper.instance.isWindows10RS5OrGreater,
+  );
 
   // see https://github.com/dart-lang/sdk/issues/43838#issuecomment-823551891
-  test('url encoding is correct for spaces', () async {
-    final mock = MockUrlLauncherPlatform();
-    UrlLauncherPlatform.instance = mock;
+  test(
+    'url encoding is correct for spaces',
+    () async {
+      final mock = MockUrlLauncherPlatform();
+      UrlLauncherPlatform.instance = mock;
 
-    await ShareWindows().share('foo bar', subject: 'bar foo');
+      await ShareWindows().share('foo bar', subject: 'bar foo');
 
-    expect(mock.url, 'mailto:?subject=bar%20foo&body=foo%20bar');
-  });
+      expect(mock.url, 'mailto:?subject=bar%20foo&body=foo%20bar');
+    },
+    skip: VersionHelper.instance.isWindows10RS5OrGreater,
+  );
 
-  test('throws when url_launcher can\'t launch uri', () async {
-    final mock = MockUrlLauncherPlatform();
-    mock.canLaunchMockValue = false;
-    UrlLauncherPlatform.instance = mock;
+  test(
+    'throws when url_launcher can\'t launch uri',
+    () async {
+      final mock = MockUrlLauncherPlatform();
+      mock.canLaunchMockValue = false;
+      UrlLauncherPlatform.instance = mock;
 
-    expect(() async => await ShareWindows().share('foo bar'), throwsException);
-  });
+      expect(
+          () async => await ShareWindows().share('foo bar'), throwsException);
+    },
+    skip: VersionHelper.instance.isWindows10RS5OrGreater,
+  );
 }
 
 class MockUrlLauncherPlatform extends UrlLauncherPlatform {

packages/share_plus/share_plus_windows/windows/.gitignore

@@ -0,0 +1,17 @@
+flutter/
+
+# Visual Studio user-specific files.
+*.suo
+*.user
+*.userosscache
+*.sln.docstates
+
+# Visual Studio build-related files.
+x64/
+x86/
+
+# Visual Studio cache files
+# files ending in .cache can be ignored
+*.[Cc]ache
+# but keep track of directories ending in .cache
+!*.[Cc]ache/

packages/share_plus/share_plus_windows/windows/CMakeLists.txt

@@ -0,0 +1,53 @@
+# The Flutter tooling requires that developers have a version of Visual Studio
+# installed that includes CMake 3.14 or later. You should not increase this
+# version, as doing so will cause the plugin to fail to compile for some
+# customers of the plugin.
+cmake_minimum_required(VERSION 3.14)
+
+# Project-level configuration.
+set(PROJECT_NAME "share_plus_windows")
+project(${PROJECT_NAME} LANGUAGES CXX)
+
+# This value is used when generating builds using this plugin, so it must
+# not be changed
+set(PLUGIN_NAME "share_plus_windows_plugin")
+
+# Any new source files that you add to the plugin should be added here.
+list(APPEND PLUGIN_SOURCES
+  "share_plus_windows_plugin.cpp"
+  "share_plus_windows_plugin.h"
+)
+
+# Define the plugin library target. Its name must not be changed (see comment
+# on PLUGIN_NAME above).
+add_library(${PLUGIN_NAME} SHARED
+  "include/share_plus_windows/share_plus_windows_plugin_c_api.h"
+  "share_plus_windows_plugin_c_api.cpp"
+  ${PLUGIN_SOURCES}
+)
+
+# Apply a standard set of build settings that are configured in the
+# application-level CMakeLists.txt. This can be removed for plugins that want
+# full control over build settings.
+apply_standard_settings(${PLUGIN_NAME})
+
+# Symbols are hidden by default to reduce the chance of accidental conflicts
+# between plugins. This should not be removed; any symbols that should be
+# exported should be explicitly exported with the FLUTTER_PLUGIN_EXPORT macro.
+set_target_properties(${PLUGIN_NAME} PROPERTIES
+  CXX_VISIBILITY_PRESET hidden)
+target_compile_definitions(${PLUGIN_NAME} PRIVATE FLUTTER_PLUGIN_IMPL)
+
+# Source include directories and library dependencies. Add any plugin-specific
+# dependencies here.
+target_include_directories(${PLUGIN_NAME} INTERFACE
+  "${CMAKE_CURRENT_SOURCE_DIR}/include")
+target_link_libraries(${PLUGIN_NAME} PRIVATE flutter flutter_wrapper_plugin)
+
+# List of absolute paths to libraries that should be bundled with the plugin.
+# This list could contain prebuilt libraries, or libraries created by an
+# external build triggered from this build file.
+set(share_plus_windows_bundled_libraries
+  ""
+  PARENT_SCOPE
+)

packages/share_plus/share_plus_windows/windows/include/share_plus_windows/share_plus_windows_plugin_c_api.h

@@ -0,0 +1,23 @@
+#ifndef FLUTTER_PLUGIN_SHARE_PLUS_WINDOWS_PLUGIN_C_API_H_
+#define FLUTTER_PLUGIN_SHARE_PLUS_WINDOWS_PLUGIN_C_API_H_
+
+#include <flutter_plugin_registrar.h>
+
+#ifdef FLUTTER_PLUGIN_IMPL
+#define FLUTTER_PLUGIN_EXPORT __declspec(dllexport)
+#else
+#define FLUTTER_PLUGIN_EXPORT __declspec(dllimport)
+#endif
+
+#if defined(__cplusplus)
+extern "C" {
+#endif
+
+FLUTTER_PLUGIN_EXPORT void SharePlusWindowsPluginCApiRegisterWithRegistrar(
+    FlutterDesktopPluginRegistrarRef registrar);
+
+#if defined(__cplusplus)
+}  // extern "C"
+#endif
+
+#endif  // FLUTTER_PLUGIN_SHARE_PLUS_WINDOWS_PLUGIN_C_API_H_