Cache program result

Plugins/Flow.Launcher.Plugin.Program/Main.cs

@@ -1,5 +1,7 @@
 using System;
+using System.Collections.Concurrent;
 using System.Collections.Generic;
+using System.Collections.Specialized;
 using System.Diagnostics;
 using System.Linq;
 using System.Threading;
@@ -9,6 +11,9 @@
 using Flow.Launcher.Infrastructure.Storage;
 using Flow.Launcher.Plugin.Program.Programs;
 using Flow.Launcher.Plugin.Program.Views;
+using Microsoft.Extensions.Caching.Memory;
+using Microsoft.Extensions.Configuration;
+using Microsoft.Extensions.Primitives;
 using Stopwatch = Flow.Launcher.Infrastructure.Stopwatch;
 
 namespace Flow.Launcher.Plugin.Program
@@ -26,9 +31,16 @@ public class Main : ISettingProvider, IAsyncPlugin, IPluginI18n, IContextMenu, I
         private static BinaryStorage<Win32[]> _win32Storage;
         private static BinaryStorage<UWP.Application[]> _uwpStorage;
 
-        public Main()
+        private static readonly List<Result> emptyResults = new();
+
+        private static readonly MemoryCacheOptions cacheOptions = new()
+        {
+            SizeLimit = 1560
+        };
+        private static MemoryCache cache = new(cacheOptions);
+
+        static Main()
         {
-
         }
 
         public void Save()
@@ -39,28 +51,29 @@ public void Save()
 
         public async Task<List<Result>> QueryAsync(Query query, CancellationToken token)
         {
+
             if (IsStartupIndexProgramsRequired)
                 _ = IndexPrograms();
 
-            Win32[] win32;
-            UWP.Application[] uwps;
+            var result = await cache.GetOrCreateAsync(query.Search, async entry =>
+             {
+                 var resultList = await Task.Run(() =>
+                          _win32s.Cast<IProgram>()
+                          .Concat(_uwps)
+                          .AsParallel()
+                          .WithCancellation(token)
+                          .Where(p => p.Enabled)
+                          .Select(p => p.Result(query.Search, _context.API))
+                          .Where(r => r?.Score > 0)
+                          .ToList());
 
-            win32 = _win32s;
-            uwps = _uwps;
+                 resultList = resultList.Any() ? resultList : emptyResults;
 
-            var result = await Task.Run(delegate
-            {
-                return win32.Cast<IProgram>()
-                    .Concat(uwps)
-                    .AsParallel()
-                    .WithCancellation(token)
-                    .Where(p => p.Enabled)
-                    .Select(p => p.Result(query.Search, _context.API))
-                    .Where(r => r?.Score > 0)
-                    .ToList();
-            }, token).ConfigureAwait(false);
-
-            token.ThrowIfCancellationRequested();
+                 entry.SetSize(resultList.Count);
+                 entry.SetSlidingExpiration(TimeSpan.FromHours(8));
+
+                 return resultList;
+             });
 
             return result;
         }
@@ -110,7 +123,7 @@ public async Task InitAsync(PluginInitContext context)
                 if (indexedWinApps && indexedUWPApps)
                     _settings.LastIndexTime = DateTime.Today;
             });
-            
+
             if (!(_win32s.Any() && _uwps.Any()))
                 await indexTask;
         }
@@ -134,6 +147,9 @@ public static async Task IndexPrograms()
             var t1 = Task.Run(IndexWin32Programs);
             var t2 = Task.Run(IndexUwpPrograms);
             await Task.WhenAll(t1, t2).ConfigureAwait(false);
+            var oldCache = cache;
+            cache = new MemoryCache(cacheOptions);
+            oldCache.Dispose();
             _settings.LastIndexTime = DateTime.Today;
         }