Runic.Platform 0.8.0-preview.2

Runic.Platform

Host-independent native-service contracts for Runic applications.

Preview API targeting .NET 10. Native providers are explicitly selected; this package has no Desktop or ASP.NET Core dependency. Runic.Application.Views.Desktop selects one for each window with services.AddRunicPlatformServices().

Services return PlatformResult<T>: Success, Unavailable with a PlatformUnavailableReason, or Failed with a PlatformFailureCode. Operations without a value return PlatformResult<PlatformUnit>. The type names carry the Platform prefix so they do not collide with System.Reactive.Unit and similar names when both namespaces are imported.

Branch on the failure code. When a provider observed a native error, Failed.Diagnostic carries a PlatformDiagnostic with its domain (HRESULT, Win32, errno, an NSError/GError domain or a D-Bus error name), numeric code and, where the operating system's error table describes the code, its message. It is for logs and support, not display. Free-form text from native services (GError and D-Bus messages, NSError descriptions) is left out, so a diagnostic contains no paths.

IFileDialogs.OpenDirectoryAsync(new OpenDirectoryOptions()) returns a PickerResult<IDirectoryLease> for one existing local directory. Keep the selected lease alive while C# filesystem operations use LocalPath; it retains native access until disposal or presentation close. The path preserves the selected identity, including Unicode and escaped filename characters. Native paths that cannot be represented exactly in C# are refused. Leases and native grants remain in C#; expose only application DTOs to a frontend.

Presentation close releases every lease the presentation still owns; on macOS this ends security-scoped access, and LocalPath throws once closing starts. Native owner closure alone does not release leases. When application work that uses a lease can outlive the window, such as recovery owned by an AcceptedWorkScope, drain that work before stopping the PresentationLifetime, or dispose the lease at the end of the work itself:

await acceptedWork.DisposeAsync(); // Work using lease.LocalPath has finished.
await presentationLifetime.DisposeAsync(); // Releases remaining leases.

User dismissal returns Dismissed, caller cancellation throws OperationCanceledException, and presentation shutdown returns Unavailable(OwnerClosed). The platform.directories.open capability reports availability when using PresentationFiles. Existing file-only implementations remain compatible and report directory selection unavailable. A custom IPickerBackend that implements OpenDirectoryAsync must also return true from SupportsDirectorySelection; PresentationFiles always calls the backend's method and throws InvalidOperationException if an undeclared backend returns a result other than Unavailable.

PickerResult<T>.Selected and PlatformResult<T>.Success deconstruct, so a caller can match and take the value in one pattern:

if (await files.OpenFileAsync(new()) is PickerResult<IReadFileLease>.Selected(var lease))
{
    await using (lease) { /* read */ }
}

Window services

IWindowPlatformServices groups the file dialogs, text clipboard and file launcher of one window, and reports their capabilities together under WindowPlatformServices.CapabilityIds. Host adapters register it, and its parts, per window scope through services.AddRunicPlatformServices(), so a ViewModel can take IFileDialogs, ITextClipboard, IDesktopFileLauncher or IWindowPlatformServices in its constructor. Runic.Application.Views.Desktop binds them to the native window when it opens. A host without a native owner registers WindowPlatformServices.Unavailable(reason), whose operations and capabilities all report that reason. Tests can use the same instance.

IDesktopSettings is application-scoped, so AddRunicPlatformServices() registers one singleton for it. A host or platform without a provider registers DesktopSettings.Unavailable(reason): reads return Unavailable(reason), and a watch emits that value once and then waits. IDesktopNotifications is registered the same way; without a provider it is DesktopNotifications.Unavailable(reason), whose requests return Unavailable(reason) and which never raises Activated.

Privileged actions

IDesktopPrivilegedActions runs a step the application declared at build time, a fixed program with bounded arguments, as the administrator after the platform's authorization prompt. The program ran is Success with its exit code; a refused authorization is Failed(PermissionDenied), a dismissed prompt Failed(UserDismissed), and no authorization service Unavailable. Arguments are an argument vector, never a shell command line. DesktopPrivilegedActions.Unavailable(reason) is the provider for hosts and platforms without one. Linux uses Polkit and pkexec through Runic.Platform.Linux.Polkit, Windows a UAC-elevated helper through Runic.Platform.Windows.Elevation, and macOS a launch daemon and Authorization Services through Runic.Platform.MacOS (guide).

Declare privileged actions

Declarations are PrivilegedActionDeclaration values that this package's build targets generate from RunicPrivilegedAction items, in any project that references Runic.Platform as a package:

<ItemGroup>
  <RunicPrivilegedAction Include="org.example.app.activate"
                         Program="/usr/libexec/example/example-helper"
                         Verb="activate"
                         Description="Activate a system configuration"
                         Message="Authentication is required to activate the system configuration."
                         MaximumArguments="1"
                         ArgumentPattern="[A-Za-z0-9._+-]+" />
</ItemGroup>

Platform packages read further metadata of their own, such as Polkit's IconName and AllowActive; see their guides. Metadata no package reads is ignored.

Each build validates the items and writes PrivilegedActions.g.cs under obj/.../runic-privileged/: an internal static partial class with one PrivilegedActionDeclaration property per action and All. The application and its privileged program both use it. Invalid items are build errors RUNICPA001 to RUNICPA009 and RUNICPA011, described in the diagnostics catalog.

The class name and namespace defaults are set when the package's targets are evaluated, after the project file, so a project's own RootNamespace applies and platform targets can read the final values.

A platform package extends the generation with a target that depends on RunicValidatePrivilegedActions, which validates the items once, and appends that target to RunicPrivilegedActionsDependsOn; RunicGeneratePrivilegedActions writes the class only after those targets succeeded. A platform package that generates its own part of the class uses a reserved property name, and adds any new one to RunicPrivilegedActionsReservedNames.