Caching local network info and using an event handler to invalidate as needed (improves menu slow down issue in FE3H) (#2761)

* Update IGeneralService.cs

Fix IPV4 local ip related frame drop in fire emblem by rewriting [CommandHipc(12)]

* Fix IPV4 Local IP Slowdown & Style Fixes

fix a missing space

* Remove unnecessary line

* Fix for hardcoding which index to use

* Replace argument with empty string.

By sending an empty string to Dns.GetHostAddresses("") you get back localhost info only.

* Add caching, undo change in GetCurrentIpAddress

Implement caching and revert the GetCurrentIP() function, speed improvements still present.

* Remove unnecessary using

* Syntax fixes and removing extra lines

Requested changes by AcK77

* Properly unsubscribe from event handler

Adds an unsubscribe in the dispose section of IGeneralService

Ryujinx.HLE/HOS/Services/Nifm/StaticService/IGeneralService.cs

@@ -14,6 +14,9 @@ namespace Ryujinx.HLE.HOS.Services.Nifm.StaticService
     {
         private GeneralServiceDetail _generalServiceDetail;
 
+        private IPInterfaceProperties _targetPropertiesCache = null;
+        private UnicastIPAddressInformation _targetAddressInfoCache = null;
+
         public IGeneralService()
         {
             _generalServiceDetail = new GeneralServiceDetail
@@ -22,6 +25,8 @@ namespace Ryujinx.HLE.HOS.Services.Nifm.StaticService
                 IsAnyInternetRequestAccepted = true // NOTE: Why not accept any internet request?
             };
 
+            NetworkChange.NetworkAddressChanged += new NetworkAddressChangedEventHandler(LocalInterfaceCacheHandler);
+
             GeneralServiceManager.Add(_generalServiceDetail);
         }
 
@@ -165,6 +170,11 @@ namespace Ryujinx.HLE.HOS.Services.Nifm.StaticService
                 return (null, null);
             }
 
+            if (_targetPropertiesCache != null && _targetAddressInfoCache != null)
+            {
+                return (_targetPropertiesCache, _targetAddressInfoCache);
+            }
+
             IPInterfaceProperties       targetProperties  = null;
             UnicastIPAddressInformation targetAddressInfo = null;
 
@@ -194,13 +204,26 @@ namespace Ryujinx.HLE.HOS.Services.Nifm.StaticService
                 }
             }
 
+            _targetPropertiesCache  = targetProperties;
+            _targetAddressInfoCache = targetAddressInfo;
+
             return (targetProperties, targetAddressInfo);
         }
 
+        private void LocalInterfaceCacheHandler(object sender, EventArgs e)
+        {
+            Logger.Info?.Print(LogClass.ServiceNifm, $"NetworkAddress changed, invalidating cached data.");
+
+            _targetPropertiesCache  = null;
+            _targetAddressInfoCache = null;
+        }
+
         protected override void Dispose(bool isDisposing)
         {
             if (isDisposing)
             {
+                NetworkChange.NetworkAddressChanged -= LocalInterfaceCacheHandler;
+
                 GeneralServiceManager.Remove(_generalServiceDetail.ClientId);
             }
         }