Avalonia.Threading.Dispatcher Testing

avalonia.threading.ps1

<#
$Dispatcher = {
    $App = @{}
    & {
        $builder = [Avalonia.AppBuilder]::Configure[Avalonia.Application]()
        $builder = [Avalonia.AppBuilderDesktopExtensions]::UsePlatformDetect( $builder )

        $App.Lifetime = [Avalonia.Controls.ApplicationLifetimes.ClassicDesktopStyleApplicationLifetime]::new()
        $App.Lifetime.ShutdownMode = [Avalonia.Controls.ShutdownMode]::OnExplicitShutdown
    
        $builder = $builder.SetupWithLifetime( $App.Lifetime )
    
        # Return early
        $App.Instance = $builder.Instance
    }

    # Return the UI thread dispatcher
    [Avalonia.Threading.Dispatcher]::UIThread
    $App.TokenSource = [System.Threading.CancellationTokenSource]::new()

    [Avalonia.Controls.DesktopApplicationExtensions]::Run( $App.Instance, $App.TokenSource.Token ) | Out-Null

}
#>

Import-Package Avalonia.Win32

$Dispatcher = & {

    # Win32 API Window Procedure (WndProc) which we will use to process Win32 API messages
    $MessageProcessor = & {

        # Reasons for chunking up the body of $MessageProcessor:
        # - Allow us to inject the ManagedThreadId into the body
        $body = @(
            {
                param(
                    [System.IntPtr] $hWnd,
                    [uint] $msg,
                    [System.IntPtr] $wParam,
                    [System.IntPtr] $lParam
                )
            }.ToString(),
            # Used to get the dispatcher and dispatcherImpl
            "`$id = $($ThreadController.Thread.ManagedThreadId)",
            
            # $_dispatcher and $_dispatcherImpl
            {
                $_threads = if( $Threads ){
                    $Threads
                } else {
                    (Get-Module -Name New-DispatchThread).Invoke({ $threads })
                }
                $_dispatcher = ($_threads.GetEnumerator() | Where-Object {
                    $_.Value.Thread.ManagedThreadId -eq $id
                }).Value.Dispatcher
                $_dispatcherImpl = &{
                    $_prop = $_dispatcher.GetType().GetProperty(
                        "_controlledImpl",
                        [System.Reflection.BindingFlags]::NonPublic `
                            -bor [System.Reflection.BindingFlags]::Instance
                        )
                    $_prop.GetValue( $_dispatcher )
                }
            }.ToString(),
            # $win32
            {
                $win32 = @{
                    "assembly" = [Avalonia.Win32PlatformOptions].Assembly
                }
                $win32.unmanaged = $win32.assembly.GetTypes() |
                    Where-Object { $_.Name -eq "UnmanagedMethods" }
                $win32.WindowsMessage = $win32.unmanaged.GetMember("WindowsMessage")
                $win32.DispatcherImpl = $_dispatcherImpl.GetType()
                    # $win32.assembly.GetTypes() |
                        # Where-Object { $_.Name -eq "Win32DispatcherImpl" }
                $win32.Platform = $win32.assembly.GetTypes() |
                    Where-Object { $_.Name -eq "Win32Platform" }

                $signals = @{
                    "WNDCLASSEX" = [Activator]::CreateInstance(
                        $win32.unmanaged.GetMember("WNDCLASSEX")
                    )
                    "WM_DISPATCH_WORK_ITEM" = ($win32.WindowsMessage.GetEnumValues() |
                        Where-Object { $_.ToString() -eq "WM_USER" })[0].value__
                    "WM_QUERYENDSESSION" = ($win32.WindowsMessage.GetEnumValues() |
                        Where-Object { $_.ToString() -eq "WM_QUERYENDSESSION" })[0].value__
                    "WM_SETTINGCHANGE" = ($win32.WindowsMessage.GetEnumValues() |
                        Where-Object { $_.ToString() -eq "WM_SETTINGCHANGE" })[0].value__
                    "WM_TIMER" = ($win32.WindowsMessage.GetEnumValues() |
                        Where-Object { $_.ToString() -eq "WM_TIMER" })[0].value__
                    "SignalW" = $win32.DispatcherImpl.GetField(
                        "SignalW",
                        [System.Reflection.BindingFlags]::NonPublic `
                            -bor [System.Reflection.BindingFlags]::Static
                        ).GetValue($null) # is 0xDEADBEAF
                    "SignalL" = $win32.DispatcherImpl.GetField(
                        "SignalL",
                        [System.Reflection.BindingFlags]::NonPublic `
                            -bor [System.Reflection.BindingFlags]::Static
                        ).GetValue($null) # is 0x12345678
                    "TIMERID_DISPATCHER" = $win32.Platform.GetField(
                        "TIMERID_DISPATCHER",
                        [System.Reflection.BindingFlags]::NonPublic `
                            -bor [System.Reflection.BindingFlags]::Static
                        ).GetValue($null) # is 1
                }
            }.ToString(),
            # Actual body
            {
                if ($msg -eq $signals.WM_DISPATCH_WORK_ITEM `
                    -and $wParam.ToInt64() -eq $signals.SignalW `
                    -and $lParam.ToInt64() -eq $signals.SignalL
                ){
                    $_dispatcherImpl?.DispatchWorkItem()
                }

                <#
                # Lifecycle control for Avalonia.Platform. Not super applicable to dispatcher
                # - WM_QUERYENDSESSION means there is a request to close the application or shutdown the computer
                # - Unlike WM_ENDSESSION, WM_QUERYENDSESSION is a request and can be denied
                if ($msg -eq $signals.WM_QUERYENDSESSION)
                {
                    if ($ShutdownRequested -ne $null)
                    {
                        $e = [ShutdownRequestedEventArgs]::new()

                        $ShutdownRequested.Invoke($null, $e)

                        if($e.Cancel)
                        {
                            # If we deny the shutdown, return C-equivalent of false
                            return [System.IntPtr]::Zero
                        }
                    }
                }
                #>

                <#
                # System Settings Changed detection for Avalonia.Platform. Not super applicable to dispatcher
                # - Is emitted whenever SystemParametersInfoA changes a system-wide setting
                # - see: https://learn.microsoft.com/en-us/windows/win32/winmsg/wm-settingchange
                # - see: https://learn.microsoft.com/en-us/windows/win32/api/winuser/nf-winuser-systemparametersinfoa
                if( $msg -eq $signals.WM_SETTINGCHANGE `
                    -and $PlatformSettings -is [Win32PlatformSettings] $win32PlatformSettings
                ){
                    $changedSetting = [System.Runtime.InteropServices.Marshal]::PtrToStringAuto($lParam)
                    if ($changedSetting -eq "ImmersiveColorSet" # dark/light mode
                        -or $changedSetting -eq "WindowsThemeElement") # high contrast mode
                    {
                        $win32PlatformSettings.OnColorValuesChanged()   
                    }
                }
                #>
                
                if( $msg -eq $signals.WM_TIMER )
                {
                    if( $wParam -eq $signals.TIMERID_DISPATCHER )
                    {
                        if( $_dispatcherImpl -ne $null )
                        {
                            $_dispatcherImpl.FireTimer()
                        }
                    }
                }

                # Handle tray icon messages
                # TrayIconImpl.ProcWnd(hWnd, msg, wParam, lParam);
                
                # if we don't return anything, the message is passed to the default message processor
                return $win32.unmanaged::DefWindowProc($hWnd, $msg, $wParam, $lParam);

            }.ToString()
        ) -join "`n"

        $body = {
            param(
                [System.IntPtr] $hWnd,
                [uint] $msg,
                [System.IntPtr] $wParam,
                [System.IntPtr] $lParam
            )
            Write-Host "MessageProcessor:" $hWnd $msg $wParam $lParam
        }

        [scriptblock]::create($body)
    }

    $constructor = [Avalonia.Threading.Dispatcher].
        GetConstructor(
            [System.Reflection.BindingFlags]::Instance -bor `
                [System.Reflection.BindingFlags]::NonPublic,
            $null,
            [type[]]@(
                [Avalonia.Threading.IDispatcherImpl]
            ),
            $null
        )
    $win32 = @{
        "assembly" = [Avalonia.Win32PlatformOptions].Assembly
    }
    $win32.unmanaged = $win32.assembly.GetTypes() |
        Where-Object { $_.Name -eq "UnmanagedMethods" }
    $win32.WNDCLASSEX = $win32.assembly.GetTypes() |
        Where-Object { $_.Name -eq "WNDCLASSEX" }
    $win32.DispatcherImpl = $win32.assembly.GetTypes() |
        Where-Object { $_.Name -eq "Win32DispatcherImpl" }
    # Avalonia.Win32.Interop.UnmanagedMethods+WndProc
    $win32.WndProc = $win32.assembly.GetTypes() |
        Where-Object { $_.Name -eq "WndProc" }

    $win32.MainHandle = $win32.unmanaged::GetModuleHandle($null)

    $win32.MesageHandle = & {
        $wnd_class_ex = [Activator]::CreateInstance($win32.WNDCLASSEX)
        $wnd_class_ex.cbSize = [System.Runtime.InteropServices.Marshal]::SizeOf($wnd_class_ex)
        $wnd_class_ex.lpfnWndProc = $MessageProcessor -As $win32.WndProc
        $wnd_class_ex.hInstance = $win32.MainHandle
        $wnd_class_ex.lpszClassName = "AvaloniaMessageWindow " + [System.Guid]::NewGuid().ToString()

        $atom = $win32.unmanaged::RegisterClassEx([ref]$wnd_class_ex)

        if( $atom -eq 0 )
        {
            $global:_error = [System.ComponentModel.Win32Exception]::new()
            throw $_error
        }

        $win32.unmanaged::CreateWindowEx(
            0, # dwExStyle
            $atom, # lpClassName
            [System.IntPtr]::Zero, # lpWindowName
            0, # dwStyle
            0, # x
            0, # y
            0, # nWidth
            0, # nHeight
            [System.IntPtr]::Zero, # hWndParent
            [System.IntPtr]::Zero, # hMenu
            [System.IntPtr]::Zero, # hInstance
            [System.IntPtr]::Zero # lpParam
        )
    }

    $dispatcher_impl = $win32.DispatcherImpl.GetConstructor([System.IntPtr]).Invoke(@($win32.MesageHandle))

    $constructor.Invoke(@($dispatcher_impl))
}

$win32 = @{
    "assembly" = [Avalonia.Win32PlatformOptions].Assembly
}
$win32.unmanaged = $win32.assembly.GetTypes() |
    Where-Object { $_.Name -eq "UnmanagedMethods" }
$win32.WNDCLASSEX = $win32.assembly.GetTypes() |
    Where-Object { $_.Name -eq "WNDCLASSEX" }
$win32.DispatcherImpl = $win32.assembly.GetTypes() |
    Where-Object { $_.Name -eq "Win32DispatcherImpl" }
# Avalonia.Win32.Interop.UnmanagedMethods+WndProc
$win32.WndProc = $win32.assembly.GetTypes() |
    Where-Object { $_.Name -eq "WndProc" }