Performance optimization: support eliminating some extraneous saving by KSP

GameData/KSPCommunityFixes/Settings.cfg

@@ -274,6 +274,11 @@ KSP_COMMUNITY_FIXES
     packedInterval = 0.5 // interval when the active vessel is timewarping
   }
 
+  // This tweak eliminates KSP's stock behavior of saving every time
+  // you exit a UI-only space center building (AC, MC, etc)
+  // and every time you delete a vessel in the Tracking Station
+  FewerSaves = false
+
   // ##########################
   // Modding
   // ##########################

KSPCommunityFixes/KSPCommunityFixes.csproj

@@ -127,6 +127,7 @@
     <Compile Include="Modding\DockingPortLockedEvents.cs" />
     <Compile Include="Modding\OnSymmetryFieldChanged.cs" />
     <Compile Include="Modding\ReflectionTypeLoadExceptionHandler.cs" />
+    <Compile Include="Performance\FewerSaves.cs" />
     <Compile Include="Performance\PQSUpdateNoMemoryAlloc.cs" />
     <Compile Include="Performance\ProgressTrackingSpeedBoost.cs" />
     <Compile Include="QoL\AutostrutActions.cs" />

KSPCommunityFixes/Performance/FewerSaves.cs

@@ -0,0 +1,108 @@
+using System;
+using HarmonyLib;
+using System.Collections.Generic;
+using UnityEngine;
+using KSP.UI.Screens;
+using KSP.UI;
+using System.Reflection.Emit;
+
+namespace KSPCommunityFixes
+{
+    public class FewerSaves : BasePatch
+    {
+        protected override Version VersionMin => new Version(1, 8, 0);
+
+        protected override void ApplyPatches(List<PatchInfo> patches)
+        {
+            patches.Add(new PatchInfo(
+                PatchMethodType.Prefix,
+                AccessTools.Method(typeof(ACSceneSpawner), nameof(ACSceneSpawner.onACDespawn)),
+                this));
+
+            patches.Add(new PatchInfo(
+                PatchMethodType.Prefix,
+                AccessTools.Method(typeof(AdministrationSceneSpawner), nameof(AdministrationSceneSpawner.onAdminDespawn)),
+                this));
+
+            patches.Add(new PatchInfo(
+                PatchMethodType.Prefix,
+                AccessTools.Method(typeof(MCSceneSpawner), nameof(MCSceneSpawner.OnMCDespawn)),
+                this));
+
+            patches.Add(new PatchInfo(
+                PatchMethodType.Prefix,
+                AccessTools.Method(typeof(RDSceneSpawner), nameof(RDSceneSpawner.onRDDespawn)),
+                this));
+
+            patches.Add(new PatchInfo(
+                PatchMethodType.Transpiler,
+                AccessTools.Method(typeof(SpaceTracking), "OnVesselDeleteConfirm"),
+                this));
+        }
+
+        static bool ACSceneSpawner_onACDespawn_Prefix(ACSceneSpawner __instance)
+        {
+            UIMasterController.Instance.RemoveCanvas(__instance.ACScreenPrefab);
+            MusicLogic.fetch.UnpauseWithCrossfade();
+            return false;
+        }
+
+        static bool AdministrationSceneSpawner_onAdminDespawn_Prefix(AdministrationSceneSpawner __instance)
+        {
+            UIMasterController.Instance.RemoveCanvas(__instance.AdministrationScreenPrefab);
+            MusicLogic.fetch.UnpauseWithCrossfade();
+            return false;
+        }
+
+        static bool MCSceneSpawner_OnMCDespawn_Prefix(MCSceneSpawner __instance)
+        {
+            UIMasterController.Instance.RemoveCanvas(__instance.missionControlPrefab);
+            MusicLogic.fetch.UnpauseWithCrossfade();
+            return false;
+        }
+
+        static bool RDSceneSpawner_onRDDespawn_Prefix(RDSceneSpawner __instance)
+        {
+            UIMasterController.Instance.RemoveCanvas(__instance.RDScreenPrefab);
+            RenderSettings.defaultReflectionMode = __instance.oldReflectionMode;
+            RenderSettings.customReflection = __instance.oldReflection;
+            MusicLogic.fetch.UnpauseWithCrossfade();
+            return false;
+        }
+
+        static IEnumerable<CodeInstruction> SpaceTracking_OnVesselDeleteConfirm_Transpiler(IEnumerable<CodeInstruction> instructions)
+        {
+            int startIndex = -1;
+            int endIndex = -1;
+
+            var codes = new List<CodeInstruction>(instructions);
+
+            for (int i = 0; i < codes.Count; i++)
+            {
+                if (codes[i].opcode == OpCodes.Ldstr &&
+                    codes[i].operand as string == "persistent")
+                {
+                    startIndex = i;
+
+                    for (int j = startIndex; j < codes.Count; j++)
+                    {
+                        if (codes[j].opcode == OpCodes.Ldarg_0)
+                        {
+                            endIndex = j;
+                            break;
+                        }
+                    }
+                    break;
+                }
+            }
+
+            if (startIndex > -1 && endIndex > -1)
+            {
+                // Cuts out the section about GamePersistence.SaveGame()
+                codes.RemoveRange(startIndex, endIndex - startIndex);
+            }
+
+            return codes;
+        }
+    }
+}