From ce1c722991fb85f251820cdcc33d60ef8a8f55b7 Mon Sep 17 00:00:00 2001
From: Shad Storhaug <shad@shadstorhaug.com>
Date: Tue, 22 Oct 2024 02:12:30 +0700
Subject: [PATCH] SWEEP: Removed FEATURE_DICTIONARY_REMOVE_CONTINUEENUMERATION.
 Updated private fields to use J2N.Collections.Generic.Dictionary<TKey,TValue>
 for a performance boost when we upgrade to J2N 3.x (GetEnumerator() currently
 boxes from struct to interface). (fixes #978)

---
 Directory.Build.targets                            |  1 -
 .../Taxonomy/WriterCache/NameIntCacheLRU.cs        | 11 +++--------
 src/Lucene.Net.TestFramework/Util/Fst/FSTTester.cs | 14 +++++---------
 src/Lucene.Net/Index/IndexWriter.cs                |  9 ++-------
 4 files changed, 10 insertions(+), 25 deletions(-)

diff --git a/Directory.Build.targets b/Directory.Build.targets
index 35988f656f..b0bcc3b8c3 100644
--- a/Directory.Build.targets
+++ b/Directory.Build.targets
@@ -46,7 +46,6 @@
   <PropertyGroup Condition=" $(TargetFramework.StartsWith('netcoreapp3.')) Or $(TargetFramework.StartsWith('net5.')) Or $(TargetFramework.StartsWith('net6.')) Or $(TargetFramework.StartsWith('net7.')) Or $(TargetFramework.StartsWith('net8.')) ">
 
     <DefineConstants>$(DefineConstants);FEATURE_ARGITERATOR</DefineConstants>
-    <DefineConstants>$(DefineConstants);FEATURE_DICTIONARY_REMOVE_CONTINUEENUMERATION</DefineConstants>
     <DefineConstants>$(DefineConstants);FEATURE_PROCESS_KILL_ENTIREPROCESSTREE</DefineConstants>
     <DefineConstants>$(DefineConstants);FEATURE_STRING_CONCAT_READONLYSPAN</DefineConstants>
 
diff --git a/src/Lucene.Net.Facet/Taxonomy/WriterCache/NameIntCacheLRU.cs b/src/Lucene.Net.Facet/Taxonomy/WriterCache/NameIntCacheLRU.cs
index e18927595c..ba990dbc48 100644
--- a/src/Lucene.Net.Facet/Taxonomy/WriterCache/NameIntCacheLRU.cs
+++ b/src/Lucene.Net.Facet/Taxonomy/WriterCache/NameIntCacheLRU.cs
@@ -4,6 +4,7 @@
 using System;
 using System.Collections.Concurrent;
 using System.Collections.Generic;
+using JCG = J2N.Collections.Generic;
 
 namespace Lucene.Net.Facet.Taxonomy.WriterCache
 {
@@ -162,13 +163,7 @@ private void CreateCache(int maxSize)
             }
             else
             {
-#if FEATURE_DICTIONARY_REMOVE_CONTINUEENUMERATION
-                cache = new Dictionary<TName, int>(capacity: 1000);
-#else
-                // LUCENENET specific - we use ConcurrentDictionary here because it supports deleting while
-                // iterating through the collection, but Dictionary does not.
-                cache = new ConcurrentDictionary<TName, int>(concurrencyLevel: 3, capacity: 1000); //no need for LRU
-#endif
+                cache = new JCG.Dictionary<TName, int>(capacity: 1000);
             }
         }
 
@@ -255,4 +250,4 @@ bool IInternalNameInt32CacheLru.MakeRoomLRU()
             return true;
         }
     }
-}
\ No newline at end of file
+}
diff --git a/src/Lucene.Net.TestFramework/Util/Fst/FSTTester.cs b/src/Lucene.Net.TestFramework/Util/Fst/FSTTester.cs
index 9b4decc83d..e173c6f72b 100644
--- a/src/Lucene.Net.TestFramework/Util/Fst/FSTTester.cs
+++ b/src/Lucene.Net.TestFramework/Util/Fst/FSTTester.cs
@@ -833,13 +833,9 @@ private void VerifyPruned(int inputMode, FST<T> fst, int prune1, int prune2)
 
             // build all prefixes
 
-#if FEATURE_DICTIONARY_REMOVE_CONTINUEENUMERATION
-            IDictionary<Int32sRef, CountMinOutput<T>> prefixes = new Dictionary<Int32sRef, CountMinOutput<T>>();
-#else
-            // LUCENENET: We use ConcurrentDictionary<TKey, TValue> because Dictionary<TKey, TValue> doesn't support
-            // deletion while iterating, but ConcurrentDictionary does.
-            IDictionary<Int32sRef, CountMinOutput<T>> prefixes = new ConcurrentDictionary<Int32sRef, CountMinOutput<T>>();
-#endif
+            // LUCENENET specific - using concrete type for the readerMap field, since it will eliminate boxing to an interface on GetEnumerator() calls
+            JCG.Dictionary<Int32sRef, CountMinOutput<T>> prefixes = new JCG.Dictionary<Int32sRef, CountMinOutput<T>>();
+
             Int32sRef scratch = new Int32sRef(10);
             foreach (InputOutput<T> pair in pairs)
             {
@@ -927,7 +923,7 @@ private void VerifyPruned(int inputMode, FST<T> fst, int prune1, int prune2)
                     if (!keep)
                     {
                         //it.remove();
-                        prefixes.Remove(ent);
+                        prefixes.Remove(prefix);
                         //System.out.println("    remove");
                     }
                     else
@@ -1028,4 +1024,4 @@ private void VerifyPruned(int inputMode, FST<T> fst, int prune1, int prune2)
             }
         }
     }
-}
\ No newline at end of file
+}
diff --git a/src/Lucene.Net/Index/IndexWriter.cs b/src/Lucene.Net/Index/IndexWriter.cs
index 23c93846ea..829c7fcd57 100644
--- a/src/Lucene.Net/Index/IndexWriter.cs
+++ b/src/Lucene.Net/Index/IndexWriter.cs
@@ -471,13 +471,8 @@ public ReaderPool(IndexWriter outerInstance)
                 this.outerInstance = outerInstance;
             }
 
-#if FEATURE_DICTIONARY_REMOVE_CONTINUEENUMERATION
-            private readonly IDictionary<SegmentCommitInfo, ReadersAndUpdates> readerMap = new Dictionary<SegmentCommitInfo, ReadersAndUpdates>();
-#else
-            // LUCENENET: We use ConcurrentDictionary<TKey, TValue> because Dictionary<TKey, TValue> doesn't support
-            // deletion while iterating, but ConcurrentDictionary does.
-            private readonly IDictionary<SegmentCommitInfo, ReadersAndUpdates> readerMap = new ConcurrentDictionary<SegmentCommitInfo, ReadersAndUpdates>();
-#endif
+            // LUCENENET specific - using concrete type for the readerMap field, since it will eliminate boxing to an interface on GetEnumerator() calls
+            private readonly JCG.Dictionary<SegmentCommitInfo, ReadersAndUpdates> readerMap = new JCG.Dictionary<SegmentCommitInfo, ReadersAndUpdates>();
 
             // used only by asserts
             public virtual bool InfoIsLive(SegmentCommitInfo info)