From 7a0f0fdf4b560789d273039059d0c3b3d3147bcd Mon Sep 17 00:00:00 2001
From: Ben Olden-Cooligan <ben.cyanfish@gmail.com>
Date: Tue, 21 Aug 2018 14:05:16 -0400
Subject: [PATCH] Cache options and poll when the progress form is visible

---
 NAPS2.Core/Scan/Sane/SaneScanDriver.cs  | 12 +++--
 NAPS2.Core/Util/CollectionExtensions.cs | 72 +++++++++++++++++++++++++
 2 files changed, 79 insertions(+), 5 deletions(-)

diff --git a/NAPS2.Core/Scan/Sane/SaneScanDriver.cs b/NAPS2.Core/Scan/Sane/SaneScanDriver.cs
index 1292e305d..55e9d3019 100644
--- a/NAPS2.Core/Scan/Sane/SaneScanDriver.cs
+++ b/NAPS2.Core/Scan/Sane/SaneScanDriver.cs
@@ -17,6 +17,8 @@ namespace NAPS2.Scan.Sane
     {
         public const string DRIVER_NAME = "sane";
 
+        private static Dictionary<string, SaneOptionCollection> SaneOptionCache = new Dictionary<string, SaneOptionCollection>();
+
         private readonly SaneWrapper saneWrapper;
         private readonly IFormFactory formFactory;
         private readonly IBlankDetector blankDetector;
@@ -59,7 +61,7 @@ namespace NAPS2.Scan.Sane
         protected override IEnumerable<ScannedImage> ScanInternal()
         {
             // TODO: Support ADF
-            var options = GetOptions();
+            var options = new Lazy<KeyValueScanOptions>(GetOptions);
             var img = Transfer(options);
             if (img != null)
             {
@@ -69,7 +71,7 @@ namespace NAPS2.Scan.Sane
 
         private KeyValueScanOptions GetOptions()
         {
-            var saneOptions = saneWrapper.GetOptions(ScanDevice.ID);
+            var saneOptions = SaneOptionCache.GetOrSet(ScanDevice.ID, () => saneWrapper.GetOptions(ScanDevice.ID));
             var options = new KeyValueScanOptions(ScanProfile.KeyValueOptions ?? new KeyValueScanOptions());
 
             bool ChooseStringOption(string name, Func<string, bool> match)
@@ -202,17 +204,17 @@ namespace NAPS2.Scan.Sane
             return options;
         }
 
-        private ScannedImage Transfer(KeyValueScanOptions options)
+        private ScannedImage Transfer(Lazy<KeyValueScanOptions> options)
         {
             Stream stream;
             if (ScanParams.NoUI)
             {
-                stream = saneWrapper.ScanOne(ScanDevice.ID, options, null);
+                stream = saneWrapper.ScanOne(ScanDevice.ID, options.Value, null);
             }
             else
             {
                 var form = formFactory.Create<FScanProgress>();
-                form.Transfer = () => saneWrapper.ScanOne(ScanDevice.ID, options, form.OnProgress);
+                form.Transfer = () => saneWrapper.ScanOne(ScanDevice.ID, options.Value, form.OnProgress);
                 form.PageNumber = 1;
                 form.ShowDialog();
 
diff --git a/NAPS2.Core/Util/CollectionExtensions.cs b/NAPS2.Core/Util/CollectionExtensions.cs
index bbd89ac6b..f26efe883 100644
--- a/NAPS2.Core/Util/CollectionExtensions.cs
+++ b/NAPS2.Core/Util/CollectionExtensions.cs
@@ -98,5 +98,77 @@ namespace NAPS2.Util
             }
             return default;
         }
+
+        /// <summary>
+        /// Gets the element for the given key, or the provided value if none is present.
+        /// </summary>
+        /// <typeparam name="TKey"></typeparam>
+        /// <typeparam name="TValue"></typeparam>
+        /// <param name="dict"></param>
+        /// <param name="key"></param>
+        /// <param name="defaultValue"></param>
+        /// <returns></returns>
+        public static TValue Get<TKey, TValue>(this Dictionary<TKey, TValue> dict, TKey key, TValue defaultValue)
+        {
+            if (dict.ContainsKey(key))
+            {
+                return dict[key];
+            }
+            return defaultValue;
+        }
+
+        /// <summary>
+        /// Gets the element for the given key, or the provided value if none is present.
+        /// </summary>
+        /// <typeparam name="TKey"></typeparam>
+        /// <typeparam name="TValue"></typeparam>
+        /// <param name="dict"></param>
+        /// <param name="key"></param>
+        /// <param name="defaultValue"></param>
+        /// <returns></returns>
+        public static TValue Get<TKey, TValue>(this Dictionary<TKey, TValue> dict, TKey key, Func<TValue> defaultValue)
+        {
+            if (dict.ContainsKey(key))
+            {
+                return dict[key];
+            }
+            return defaultValue();
+        }
+
+        /// <summary>
+        /// Gets the element for the given key, or sets and returns the provided value if none is present.
+        /// </summary>
+        /// <typeparam name="TKey"></typeparam>
+        /// <typeparam name="TValue"></typeparam>
+        /// <param name="dict"></param>
+        /// <param name="key"></param>
+        /// <param name="defaultValue"></param>
+        /// <returns></returns>
+        public static TValue GetOrSet<TKey, TValue>(this Dictionary<TKey, TValue> dict, TKey key, TValue defaultValue)
+        {
+            if (!dict.ContainsKey(key))
+            {
+                dict[key] = defaultValue;
+            }
+            return dict[key];
+        }
+
+        /// <summary>
+        /// Gets the element for the given key, or sets and returns the provided value if none is present.
+        /// </summary>
+        /// <typeparam name="TKey"></typeparam>
+        /// <typeparam name="TValue"></typeparam>
+        /// <param name="dict"></param>
+        /// <param name="key"></param>
+        /// <param name="defaultValue"></param>
+        /// <returns></returns>
+        public static TValue GetOrSet<TKey, TValue>(this Dictionary<TKey, TValue> dict, TKey key, Func<TValue> defaultValue)
+        {
+            if (!dict.ContainsKey(key))
+            {
+                dict[key] = defaultValue();
+            }
+            return dict[key];
+        }
     }
 }