Innovenergy_trunk/csharp/lib/Protocols/DBus/Daemon/DBusDaemonConnection.cs

using System.Reactive.Concurrency;
using System.Reactive.Linq;
using InnovEnergy.Lib.Protocols.DBus.Protocol;
using InnovEnergy.Lib.Protocols.DBus.Protocol.DataTypes;
using InnovEnergy.Lib.Protocols.DBus.Utils;
using static InnovEnergy.Lib.Protocols.DBus.Daemon.DBusDaemonApi;

namespace InnovEnergy.Lib.Protocols.DBus.Daemon;

public class DBusDaemonConnection : DBusMessageStream
{
    public String LocalName { get; }
    public IObservable<ServiceChanged> Services { get; }

    public DBusDaemonConnection(Bus bus) : base(bus)
    {
        LocalName = Hello().Result; // Note: blocking (no async constructors)

        Services = Observable
                  .Defer(this.ObserveServices)
                  .SubscribeOn(TaskPoolScheduler.Default) // ObserveServices blocks
                  .Replay(1)
                  .RefCount();
    }

    private Task<String> Hello() => CallDaemon<String>("Hello");

    public Task<RequestNameReply> RequestName(String name, RequestNameOptions options = RequestNameOptions.DoNotQueue)
    {
        return CallDaemon<RequestNameReply>("RequestName", (name, (UInt32)options));
    }

    public Task<ReleaseNameReply> ReleaseName(String name)
    {
        return CallDaemon<ReleaseNameReply>("ReleaseName", name);
    }

    public Task<IReadOnlyList<String>> ListNames()
    {
        return CallDaemon<IReadOnlyList<String>>("ListNames");
    }

    public Task<String> GetNameOwner(String name)
    {
        return CallDaemon<String>("GetNameOwner", name);
    }

    public Task<UInt32> GetConnectionUnixUser(String name)
    {
        return CallDaemon<UInt32>("GetConnectionUnixUser", name);
    }

    public Task<UInt32> GetConnectionUnixProcessId(String name)
    {
        return CallDaemon<UInt32>("GetConnectionUnixProcessID", name);
    }

    public Task AddMatch(IMatchRule matchRule)
    {
        return CallDaemon<Object>("AddMatch", matchRule.ToString());
    }

    public Task RemoveMatch(IMatchRule matchRule)
    {
        return CallDaemon<Object>("RemoveMatch", matchRule.ToString());
    }

    // TODO: ListQueuedOwners
    // TODO: ListActivatableNames
    // TODO: NameHasOwner
    // TODO: StartServiceByName
    // TODO: UpdateActivationEnvironment
    // TODO: GetConnectionCredentials
    // TODO: GetAdtAuditSessionData
    // TODO: GetConnectionSELinuxSecurityContext
    // TODO: GetId
    // TODO: BecomeMonitor
    // TODO: Features

    private Task<T> CallDaemon<T>(String member, Object? payload = null)
    {
        var msg = Message.MethodCall
        (
            member: member,
            payload: payload,
            replyExpected: true,
            destination: ServiceName,
            objectPath : DBusDaemonApi.ObjectPath,
            @interface : Interface
        );


        return CallMethod<T>(msg);
    }

    public IEnumerable<(String name, String id)> GetNameOwners()
    {
        var names = ListNames()
                   .Result;

        return names
              .Where(DBusDaemonApi.IsBusName)
              .Select(name => (name, id: GetOwner(name)))
              .Where(nid => nid.id != null)!;

        String? GetOwner(String busName)
        {
            return GetNameOwner(busName)
                  .ContinueWith(t => t.IsCompletedSuccessfully ? t.Result : null)
                  .Result;
        }
    }


    // TODO: ObserveSignalMessages without Daemon (implement one class up, then override here)

    /// <summary>
    ///
    /// </summary>
    /// <param name="sender">if present, filter by sender name or id</param>
    /// <param name="interface">if present, only accept messages matching interface</param>
    /// <param name="objectPath">if present, only accept messages with matching object path. The objectPath parameter
    /// MAY end with a *. In this case messages whose object path starts with the string preceding the * will match.</param>
    /// <param name="member">if present, only accept messages matching interface</param>
    /// <returns></returns>
    public IObservable<Message> ObserveSignalMessages(String? sender     = default,
                                                      String? @interface = default,
                                                  ObjectPath? objectPath = default,
                                                      String? member     = default)
    {
        var prefix = objectPath.HasValue && objectPath.Value.Path.EndsWith("*")
                   ? new ObjectPath(objectPath.Value.Path.TrimEnd('*'))
                   : (ObjectPath?)null;

        var path = prefix is null && objectPath.HasValue
                 ? objectPath
                 : null;


        IMatchRule matchRule = new SignalMatchRule
        {
            Path          = path,
            Member        = member,
            Sender        = sender,
            Interface     = @interface,
            PathNamespace = prefix
        };

        DBusDaemonConnection Connect()
        {
            var connection = new DBusDaemonConnection(Bus); // clone connection, note: blocking

            connection.AddMatch(matchRule);                 // fire and forget  TODO: bubble exception
            connection.AddDisposeAction(() => connection.RemoveMatch(matchRule));  // fire and forget

            return connection;
        }

        var signals = Observable
                     .Using(Connect, c => c.IncomingMessages)
                     .DumpErrors()
                     .SubscribeOn(TaskPoolScheduler.Default);  // avoid blocking subscribe

        const String daemon = ServiceName;

        return sender is daemon
             ? signals                                  // return ALL signals
             : signals.Where(s => s.Sender != daemon);  // filter out signals from daemon, NameOwnerChanged etc.
    }


}