From 5745a984aaba249baa15a8fa7f257e7c6858fd0e Mon Sep 17 00:00:00 2001
From: Alekhya <reddykalekhya@gmail.com>
Date: Fri, 26 Jun 2020 10:20:35 -0700
Subject: [PATCH] Partial Fix for Memory issue - Limiting the number of
 ImageSources cached (#4433)

* reducing storage of images

* Added task.run

* cleaned up code and added comments

* Renamed variable

* refactored code

* Removed task.run because it was leading to race conditions in the concurrent dictionary and it was taking only upto 10 ms for reordering the dictionary

* Added comments and fixed variable name
---
 .../Wox.Infrastructure/Image/ImageCache.cs    | 29 +++++++++++++++++--
 .../Wox.Infrastructure/Image/ImageLoader.cs   |  6 +++-
 2 files changed, 31 insertions(+), 4 deletions(-)

diff --git a/src/modules/launcher/Wox.Infrastructure/Image/ImageCache.cs b/src/modules/launcher/Wox.Infrastructure/Image/ImageCache.cs
index 85e477add9..835ccdcea1 100644
--- a/src/modules/launcher/Wox.Infrastructure/Image/ImageCache.cs
+++ b/src/modules/launcher/Wox.Infrastructure/Image/ImageCache.cs
@@ -2,6 +2,7 @@
 using System.Collections.Concurrent;
 using System.Collections.Generic;
 using System.Linq;
+using System.Threading.Tasks;
 using System.Windows.Media;
 
 namespace Wox.Infrastructure.Image
@@ -9,10 +10,10 @@ namespace Wox.Infrastructure.Image
     [Serializable]
     public class ImageCache
     {
-        private const int MaxCached = 5000;
+        private const int MaxCached = 50;
         public ConcurrentDictionary<string, int> Usage = new ConcurrentDictionary<string, int>();
         private readonly ConcurrentDictionary<string, ImageSource> _data = new ConcurrentDictionary<string, ImageSource>();
-
+        private const int permissibleFactor = 2;
 
         public ImageSource this[string path]
         {
@@ -22,7 +23,29 @@ namespace Wox.Infrastructure.Image
                 var i = _data[path];
                 return i;
             }
-            set { _data[path] = value; }
+            set 
+            {
+                _data[path] = value;
+
+                // To prevent the dictionary from drastically increasing in size by caching images, the dictionary size is not allowed to grow more than the permissibleFactor * maxCached size
+                // This is done so that we don't constantly perform this resizing operation and also maintain the image cache size at the same time
+                if (_data.Count > permissibleFactor * MaxCached)
+                {
+                    // This function resizes the Usage dictionary, taking the top 'maxCached' number of items and filtering the image icons that are not accessed frequently.
+                    Cleanup();
+
+                    // To delete the images from the data dictionary based on the resizing of the Usage Dictionary.
+                    foreach (var key in _data.Keys)
+                    {
+                        int dictValue;
+                        if (!Usage.TryGetValue(key, out dictValue))
+                        {
+                            ImageSource imgSource;
+                            _data.TryRemove(key, out imgSource);
+                        }
+                    }
+                }
+            }
         }
 
         public void Cleanup()
diff --git a/src/modules/launcher/Wox.Infrastructure/Image/ImageLoader.cs b/src/modules/launcher/Wox.Infrastructure/Image/ImageLoader.cs
index 6fa9a004a5..997cc14ca8 100644
--- a/src/modules/launcher/Wox.Infrastructure/Image/ImageLoader.cs
+++ b/src/modules/launcher/Wox.Infrastructure/Image/ImageLoader.cs
@@ -185,9 +185,13 @@ namespace Wox.Infrastructure.Image
                 string hash = EnableImageHash ? _hashGenerator.GetHashFromImage(img) : null;
                 if (hash != null)
                 {
+                    int ImageCacheValue;
                     if (GuidToKey.TryGetValue(hash, out string key))
                     { // image already exists
-                        img = ImageCache[key];
+                        if(ImageCache.Usage.TryGetValue(path, out ImageCacheValue))
+                        {
+                            img = ImageCache[key];
+                        }
                     }
                     else
                     { // new guid