[macOS] Add platform_channel sample/test (#123141)

Adds a macOS implementation of the platform_channel example,
demonstrating method channels and event channels with a battery power
plugin.

Adds platform_channel_sample_test_macos macOS host test to verify the
sample works.

Issue: https://github.com/flutter/flutter/issues/79204

.ci.yaml

@@ -2972,6 +2972,20 @@ targets:
         ]
       task_name: platform_view_macos__start_up
 
+  - name: Mac platform_channel_sample_test_macos
+    bringup: true
+    recipe: devicelab/devicelab_drone
+    presubmit: false
+    timeout: 60
+    properties:
+      dependencies: >-
+        [
+          {"dependency": "xcode", "version": "14a5294e"}
+        ]
+      tags: >
+        ["devicelab", "hostonly", "mac"]
+      task_name: platform_channel_sample_test_macos
+
   - name: Mac plugin_dependencies_test
     recipe: devicelab/devicelab_drone
     timeout: 60

TESTOWNERS

@@ -250,6 +250,7 @@
 /dev/devicelab/bin/tasks/module_test.dart @zanderso @flutter/tool
 /dev/devicelab/bin/tasks/module_test_ios.dart @jmagman @flutter/tool
 /dev/devicelab/bin/tasks/native_ui_tests_macos.dart @cbracken @flutter/desktop
+/dev/devicelab/bin/tasks/platform_channel_sample_test_macos.dart @cbracken @flutter/desktop
 /dev/devicelab/bin/tasks/platform_channel_sample_test_windows.dart @cbracken @flutter/desktop
 /dev/devicelab/bin/tasks/platform_view_macos__start_up.dart @a-wallen @flutter/desktop
 /dev/devicelab/bin/tasks/platform_view_win_desktop__start_up.dart @yaakovschectman @flutter/desktop

dev/devicelab/bin/tasks/platform_channel_sample_test_macos.dart

+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'package:flutter_devicelab/framework/framework.dart';
+import 'package:flutter_devicelab/tasks/integration_tests.dart';
+
+Future<void> main() async {
+  await task(createPlatformChannelSampleTest(deviceIdOverride: 'macos'));
+}

examples/platform_channel/macos/.gitignore

+# Flutter-related
+**/Flutter/ephemeral/
+**/Pods/
+
+# Xcode-related
+**/dgph
+**/xcuserdata/

examples/platform_channel/macos/Flutter/Flutter-Debug.xcconfig

+#include "ephemeral/Flutter-Generated.xcconfig"

examples/platform_channel/macos/Flutter/Flutter-Release.xcconfig

+#include "ephemeral/Flutter-Generated.xcconfig"

examples/platform_channel/macos/Runner.xcodeproj/project.xcworkspace/xcshareddata/IDEWorkspaceChecks.plist

+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+	<key>IDEDidComputeMac32BitWarning</key>
+	<true/>
+</dict>
+</plist>

examples/platform_channel/macos/Runner.xcodeproj/xcshareddata/xcschemes/Runner.xcscheme

+<?xml version="1.0" encoding="UTF-8"?>
+<Scheme
+   LastUpgradeVersion = "1300"
+   version = "1.3">
+   <BuildAction
+      parallelizeBuildables = "YES"
+      buildImplicitDependencies = "YES">
+      <BuildActionEntries>
+         <BuildActionEntry
+            buildForTesting = "YES"
+            buildForRunning = "YES"
+            buildForProfiling = "YES"
+            buildForArchiving = "YES"
+            buildForAnalyzing = "YES">
+            <BuildableReference
+               BuildableIdentifier = "primary"
+               BlueprintIdentifier = "33CC10EC2044A3C60003C045"
+               BuildableName = "platform_channel.app"
+               BlueprintName = "Runner"
+               ReferencedContainer = "container:Runner.xcodeproj">
+            </BuildableReference>
+         </BuildActionEntry>
+      </BuildActionEntries>
+   </BuildAction>
+   <TestAction
+      buildConfiguration = "Debug"
+      selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
+      selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      shouldUseLaunchSchemeArgsEnv = "YES">
+      <MacroExpansion>
+         <BuildableReference
+            BuildableIdentifier = "primary"
+            BlueprintIdentifier = "33CC10EC2044A3C60003C045"
+            BuildableName = "platform_channel.app"
+            BlueprintName = "Runner"
+            ReferencedContainer = "container:Runner.xcodeproj">
+         </BuildableReference>
+      </MacroExpansion>
+      <Testables>
+         <TestableReference
+            skipped = "NO"
+            parallelizable = "YES">
+            <BuildableReference
+               BuildableIdentifier = "primary"
+               BlueprintIdentifier = "331C80D4294CF70F00263BE5"
+               BuildableName = "RunnerTests.xctest"
+               BlueprintName = "RunnerTests"
+               ReferencedContainer = "container:Runner.xcodeproj">
+            </BuildableReference>
+         </TestableReference>
+      </Testables>
+   </TestAction>
+   <LaunchAction
+      buildConfiguration = "Debug"
+      selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
+      selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      launchStyle = "0"
+      useCustomWorkingDirectory = "NO"
+      ignoresPersistentStateOnLaunch = "NO"
+      debugDocumentVersioning = "YES"
+      debugServiceExtension = "internal"
+      allowLocationSimulation = "YES">
+      <BuildableProductRunnable
+         runnableDebuggingMode = "0">
+         <BuildableReference
+            BuildableIdentifier = "primary"
+            BlueprintIdentifier = "33CC10EC2044A3C60003C045"
+            BuildableName = "platform_channel.app"
+            BlueprintName = "Runner"
+            ReferencedContainer = "container:Runner.xcodeproj">
+         </BuildableReference>
+      </BuildableProductRunnable>
+   </LaunchAction>
+   <ProfileAction
+      buildConfiguration = "Profile"
+      shouldUseLaunchSchemeArgsEnv = "YES"
+      savedToolIdentifier = ""
+      useCustomWorkingDirectory = "NO"
+      debugDocumentVersioning = "YES">
+      <BuildableProductRunnable
+         runnableDebuggingMode = "0">
+         <BuildableReference
+            BuildableIdentifier = "primary"
+            BlueprintIdentifier = "33CC10EC2044A3C60003C045"
+            BuildableName = "platform_channel.app"
+            BlueprintName = "Runner"
+            ReferencedContainer = "container:Runner.xcodeproj">
+         </BuildableReference>
+      </BuildableProductRunnable>
+   </ProfileAction>
+   <AnalyzeAction
+      buildConfiguration = "Debug">
+   </AnalyzeAction>
+   <ArchiveAction
+      buildConfiguration = "Release"
+      revealArchiveInOrganizer = "YES">
+   </ArchiveAction>
+</Scheme>

examples/platform_channel/macos/Runner.xcworkspace/contents.xcworkspacedata

+<?xml version="1.0" encoding="UTF-8"?>
+<Workspace
+   version = "1.0">
+   <FileRef
+      location = "group:Runner.xcodeproj">
+   </FileRef>
+</Workspace>

examples/platform_channel/macos/Runner.xcworkspace/xcshareddata/IDEWorkspaceChecks.plist

+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+	<key>IDEDidComputeMac32BitWarning</key>
+	<true/>
+</dict>
+</plist>

examples/platform_channel/macos/Runner/AppDelegate.swift

+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import Cocoa
+import FlutterMacOS
+
+@NSApplicationMain
+class AppDelegate: FlutterAppDelegate {
+  override func applicationShouldTerminateAfterLastWindowClosed(_ sender: NSApplication) -> Bool {
+    return true
+  }
+}

examples/platform_channel/macos/Runner/Assets.xcassets/Contents.json

+{
+  "info" : {
+    "author" : "xcode",
+    "version" : 1
+  }
+}

examples/platform_channel/macos/Runner/Configs/AppInfo.xcconfig

+// Application-level settings for the Runner target.
+//
+// This may be replaced with something auto-generated from metadata (e.g., pubspec.yaml) in the
+// future. If not, the values below would default to using the project name when this becomes a
+// 'flutter create' template.
+
+// The application's name. By default this is also the title of the Flutter window.
+PRODUCT_NAME = platform_channel
+
+// The application's bundle identifier
+PRODUCT_BUNDLE_IDENTIFIER = com.example.platformChannel
+
+// The copyright displayed in application information
+PRODUCT_COPYRIGHT = Copyright © 2023 com.example. All rights reserved.

examples/platform_channel/macos/Runner/Configs/Debug.xcconfig

+#include "../../Flutter/Flutter-Debug.xcconfig"
+#include "Warnings.xcconfig"

examples/platform_channel/macos/Runner/Configs/Release.xcconfig

+#include "../../Flutter/Flutter-Release.xcconfig"
+#include "Warnings.xcconfig"

examples/platform_channel/macos/Runner/Configs/Warnings.xcconfig

+WARNING_CFLAGS = -Wall -Wconditional-uninitialized -Wnullable-to-nonnull-conversion -Wmissing-method-return-type -Woverlength-strings
+GCC_WARN_UNDECLARED_SELECTOR = YES
+CLANG_UNDEFINED_BEHAVIOR_SANITIZER_NULLABILITY = YES
+CLANG_WARN_UNGUARDED_AVAILABILITY = YES_AGGRESSIVE
+CLANG_WARN__DUPLICATE_METHOD_MATCH = YES
+CLANG_WARN_PRAGMA_PACK = YES
+CLANG_WARN_STRICT_PROTOTYPES = YES
+CLANG_WARN_COMMA = YES
+GCC_WARN_STRICT_SELECTOR_MATCH = YES
+CLANG_WARN_OBJC_REPEATED_USE_OF_WEAK = YES
+CLANG_WARN_OBJC_IMPLICIT_RETAIN_SELF = YES
+GCC_WARN_SHADOW = YES
+CLANG_WARN_UNREACHABLE_CODE = YES

examples/platform_channel/macos/Runner/DebugProfile.entitlements

+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+	<key>com.apple.security.app-sandbox</key>
+	<true/>
+	<key>com.apple.security.cs.allow-jit</key>
+	<true/>
+	<key>com.apple.security.network.server</key>
+	<true/>
+</dict>
+</plist>

examples/platform_channel/macos/Runner/Info.plist

+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+	<key>CFBundleDevelopmentRegion</key>
+	<string>$(DEVELOPMENT_LANGUAGE)</string>
+	<key>CFBundleExecutable</key>
+	<string>$(EXECUTABLE_NAME)</string>
+	<key>CFBundleIconFile</key>
+	<string></string>
+	<key>CFBundleIdentifier</key>
+	<string>$(PRODUCT_BUNDLE_IDENTIFIER)</string>
+	<key>CFBundleInfoDictionaryVersion</key>
+	<string>6.0</string>
+	<key>CFBundleName</key>
+	<string>$(PRODUCT_NAME)</string>
+	<key>CFBundlePackageType</key>
+	<string>APPL</string>
+	<key>CFBundleShortVersionString</key>
+	<string>$(FLUTTER_BUILD_NAME)</string>
+	<key>CFBundleVersion</key>
+	<string>$(FLUTTER_BUILD_NUMBER)</string>
+	<key>LSMinimumSystemVersion</key>
+	<string>$(MACOSX_DEPLOYMENT_TARGET)</string>
+	<key>NSHumanReadableCopyright</key>
+	<string>$(PRODUCT_COPYRIGHT)</string>
+	<key>NSMainNibFile</key>
+	<string>MainMenu</string>
+	<key>NSPrincipalClass</key>
+	<string>FlutterApplication</string>
+</dict>
+</plist>

examples/platform_channel/macos/Runner/MainFlutterWindow.swift

+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import Cocoa
+import FlutterMacOS
+
+class MainFlutterWindow: NSWindow, FlutterStreamHandler, PowerSourceStateChangeDelegate {
+  private let powerSource = PowerSource()
+  private let stateChangeSource = PowerSourceStateChangeHandler()
+  private var eventSink: FlutterEventSink?
+
+  override func awakeFromNib() {
+    let flutterViewController = FlutterViewController.init()
+    let windowFrame = self.frame
+    self.contentViewController = flutterViewController
+    self.setFrame(windowFrame, display: true)
+
+    // Register battery method channel.
+    let registrar = flutterViewController.registrar(forPlugin: "BatteryLevel")
+    let batteryChannel = FlutterMethodChannel(
+      name: "samples.flutter.io/battery",
+      binaryMessenger: registrar.messenger)
+    batteryChannel.setMethodCallHandler({ [weak self] (call, result) in
+      switch call.method {
+      case "getBatteryLevel":
+        let level = self?.powerSource.getCurrentCapacity()
+        if level == -1 {
+          result(
+            FlutterError(
+              code: "UNAVAILABLE",
+              message: "Battery info unavailable",
+              details: nil))
+        }
+        result(level)
+      default:
+        result(FlutterMethodNotImplemented)
+      }
+    })
+
+    // Register charging event channel.
+    let chargingChannel = FlutterEventChannel(
+      name: "samples.flutter.io/charging",
+      binaryMessenger: registrar.messenger)
+    chargingChannel.setStreamHandler(self)
+
+    RegisterGeneratedPlugins(registry: flutterViewController)
+
+    super.awakeFromNib()
+  }
+
+  func onListen(withArguments arguments: Any?, eventSink events: @escaping FlutterEventSink)
+    -> FlutterError?
+  {
+    self.eventSink = events
+    self.emitPowerStatusEvent()
+    self.stateChangeSource.delegate = self
+    return nil
+  }
+
+  func onCancel(withArguments arguments: Any?) -> FlutterError? {
+    self.stateChangeSource.delegate = nil
+    self.eventSink = nil
+    return nil
+  }
+
+  func onPowerSourceStateChanged() {
+    self.emitPowerStatusEvent()
+  }
+
+  func emitPowerStatusEvent() {
+    if let sink = self.eventSink {
+      switch self.powerSource.getPowerState() {
+      case .ac:
+        sink("charging")
+      case .battery:
+        sink("discharging")
+      case .unknown:
+        sink("UNAVAILABLE")
+      }
+    }
+  }
+
+}

examples/platform_channel/macos/Runner/PowerSource.swift

+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import Foundation
+import IOKit.ps
+
+enum PowerState {
+  case ac
+  case battery
+  case unknown
+}
+
+/// A convenience wrapper for an IOKit power source.
+class PowerSource {
+  let info = IOPSCopyPowerSourcesInfo().takeRetainedValue()
+  lazy var sources = IOPSCopyPowerSourcesList(info).takeRetainedValue() as Array
+
+  /// Returns the current power source capacity. Apple-defined power sources will return this value
+  /// as a percentage.
+  func getCurrentCapacity() -> Int {
+    if let source = sources.first {
+      let description =
+        IOPSGetPowerSourceDescription(info, source).takeUnretainedValue() as! [String: AnyObject]
+      if let level = description[kIOPSCurrentCapacityKey] as? Int {
+        return level
+      }
+    }
+    return -1
+  }
+
+  /// Returns whether the device is drawing battery power or connected to an external power source.
+  func getPowerState() -> PowerState {
+    if !sources.isEmpty {
+      let source = sources[0]
+      let description =
+        IOPSGetPowerSourceDescription(info, source).takeUnretainedValue() as! [String: AnyObject]
+      if let state = description[kIOPSPowerSourceStateKey] as? String {
+        switch state {
+        case kIOPSACPowerValue:
+          return .ac
+        case kIOPSBatteryPowerValue:
+          return .battery
+        default:
+          return .unknown
+        }
+      }
+    }
+    return .unknown
+  }
+}
+
+protocol PowerSourceStateChangeDelegate: AnyObject {
+  func onPowerSourceStateChanged()
+}
+
+/// A listener for system power source state change events. Notifies the delegate on each event.
+class PowerSourceStateChangeHandler {
+  private var runLoopSource: CFRunLoopSource?
+  weak var delegate: PowerSourceStateChangeDelegate?
+
+  init() {
+    let context = UnsafeMutableRawPointer(Unmanaged.passUnretained(self).toOpaque())
+    self.runLoopSource = IOPSNotificationCreateRunLoopSource(
+      { (context: UnsafeMutableRawPointer?) in
+        let weakSelf = Unmanaged<PowerSourceStateChangeHandler>.fromOpaque(
+          UnsafeRawPointer(context!)
+        ).takeUnretainedValue()
+        weakSelf.delegate?.onPowerSourceStateChanged()
+      }, context
+    ).takeRetainedValue()
+    CFRunLoopAddSource(CFRunLoopGetCurrent(), self.runLoopSource, .defaultMode)
+  }
+
+  deinit {
+    CFRunLoopRemoveSource(CFRunLoopGetCurrent(), self.runLoopSource, .defaultMode)
+  }
+}

examples/platform_channel/macos/Runner/Release.entitlements

+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+	<key>com.apple.security.app-sandbox</key>
+	<true/>
+</dict>
+</plist>

examples/platform_channel/macos/RunnerTests/RunnerTests.swift

+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import FlutterMacOS
+import Cocoa
+import XCTest
+
+class RunnerTests: XCTestCase {
+
+  func testExample() {
+    // If you add code to the Runner application, consider adding tests here.
+    // See https://developer.apple.com/documentation/xctest for more information about using XCTest.
+  }
+
+}