Horizon: Implement arp:r and arp:w services (#5802)

* Horizon: Implement arp:r and arp:w services

* Fix formatting

* Remove HLE arp services

* Revert "Remove HLE arp services"

This reverts commit c576fcccadb963db56b96bacabd1c1ac7abfb1ab.

* Keep LibHac impl since it's used in bcat

* Addresses gdkchan's feedback

* ArpApi in PrepoIpcServer and remove LmApi

* Fix 2

* Fixes ArpApi init

* Fix encoding

* Update PrepoService.cs

* Fix prepo

1 files changed, 75 insertions, 0 deletions

diff --git a/src/Ryujinx.Horizon/Arp/Ipc/Writer.cs b/src/Ryujinx.Horizon/Arp/Ipc/Writer.cs
new file mode 100644
index 00000000..29c98b77
--- /dev/null
+++ b/src/Ryujinx.Horizon/Arp/Ipc/Writer.cs
@@ -0,0 +1,75 @@
+using Ryujinx.Horizon.Common;
+using Ryujinx.Horizon.Sdk.Arp;
+using Ryujinx.Horizon.Sdk.Arp.Detail;
+using Ryujinx.Horizon.Sdk.OsTypes;
+using Ryujinx.Horizon.Sdk.Sf;
+
+namespace Ryujinx.Horizon.Arp.Ipc
+{
+    partial class Writer : IWriter, IServiceObject
+    {
+        private readonly ApplicationInstanceManager _applicationInstanceManager;
+
+        public Writer(ApplicationInstanceManager applicationInstanceManager)
+        {
+            _applicationInstanceManager = applicationInstanceManager;
+        }
+
+        [CmifCommand(0)]
+        public Result AcquireRegistrar(out IRegistrar registrar)
+        {
+            if (_applicationInstanceManager.Entries[0] != null)
+            {
+                if (_applicationInstanceManager.Entries[1] != null)
+                {
+                    registrar = null;
+
+                    return ArpResult.NoFreeInstance;
+                }
+                else
+                {
+                    _applicationInstanceManager.Entries[1] = new ApplicationInstance();
+
+                    registrar = new Registrar(_applicationInstanceManager.Entries[1]);
+                }
+            }
+            else
+            {
+                _applicationInstanceManager.Entries[0] = new ApplicationInstance();
+
+                registrar = new Registrar(_applicationInstanceManager.Entries[0]);
+            }
+
+            return Result.Success;
+        }
+
+        [CmifCommand(1)]
+        public Result UnregisterApplicationInstance(ulong applicationInstanceId)
+        {
+            if (_applicationInstanceManager.Entries[applicationInstanceId] != null)
+            {
+                _applicationInstanceManager.Entries[applicationInstanceId] = null;
+            }
+
+            Os.SignalSystemEvent(ref _applicationInstanceManager.SystemEvent);
+
+            return Result.Success;
+        }
+
+        [CmifCommand(2)]
+        public Result AcquireApplicationProcessPropertyUpdater(out IUpdater updater, ulong applicationInstanceId)
+        {
+            updater = new Updater(_applicationInstanceManager, applicationInstanceId, false);
+
+            return Result.Success;
+        }
+
+        [CmifCommand(3)]
+        public Result AcquireApplicationCertificateUpdater(out IUpdater updater, ulong applicationInstanceId)
+        {
+            updater = new Updater(_applicationInstanceManager, applicationInstanceId, true);
+
+            return Result.Success;
+        }
+    }
+}