Add new setting maxhlduringincsearch for limiting highlights with incsearch

This can otherwise lead to great slowdown particularly during initial typed letters.
Because with incsearch highlighting is triggered and block, this means starting your
search will highlight up to thousands of the same character only refined later.
With this new setting this skips highlighting (during incsearch only) when above
threshold, or keeps old behavior if set to -1.

Author: davidot

src/main/java/com/maddyhome/idea/vim/helper/SearchHighlightsHelper.kt

@@ -107,6 +107,12 @@ private fun updateSearchHighlights(
       && (currentEditor == null || it.projectId == currentEditor.projectId)
   }
 
+  val shouldIgnoreCase = pattern == null || shouldIgnoreCase(pattern, shouldIgnoreSmartCase)
+
+  var maxhlduringincsearch = injector.globalOptions().maxhlduringincsearch
+  if (maxhlduringincsearch < 0)
+    maxhlduringincsearch = Int.MAX_VALUE
+
   editors.forEach {
     val editor = it.ij
     var currentMatchOffset = -1
@@ -136,13 +142,24 @@ private fun updateSearchHighlights(
             pattern,
             searchStartLine,
             searchEndLine,
-            shouldIgnoreCase(pattern, shouldIgnoreSmartCase)
+            shouldIgnoreCase
           )
         if (results.isNotEmpty()) {
-          if (editor === currentEditor?.ij) {
-            currentMatchOffset = findClosestMatch(results, initialOffset, count1, forwards)
+          // Only in incsearch is current editor not null, then check result size
+          val showHighlightsInEditor = currentEditor == null || results.size < maxhlduringincsearch
+          if (editor == currentEditor?.ij) {
+            val currentMatchIndex = findClosestMatch(results, initialOffset, count1, forwards)
+            currentMatchOffset = if (currentMatchIndex == -1) -1 else results[currentMatchIndex].startOffset
+
+            if (!showHighlightsInEditor) {
+              // Always highlight at least the "current" match in the active editor
+              highlightSearchResults(editor, pattern, listOf(results[currentMatchIndex]), currentMatchOffset)
+            }
+          }
+
+          if (showHighlightsInEditor) {
+            highlightSearchResults(editor, pattern, results, currentMatchOffset)
           }
-          highlightSearchResults(editor, pattern, results, currentMatchOffset)
         }
       }
       editor.vimLastSearch = pattern
@@ -237,7 +254,7 @@ private fun findClosestMatch(
     return -1
   }
 
-  return sortedResults[nextIndex % results.size].startOffset
+  return nextIndex % results.size
 }
 
 internal fun highlightSearchResults(

src/main/resources/dictionaries/ideavim.dic

@@ -23,6 +23,7 @@ keymodel
 lookupKeys
 mapleader
 matchpairs
+maxhlduringincsearch
 maxmapdepth
 nrformats
 operatorfunc

vim-engine/src/main/kotlin/com/maddyhome/idea/vim/api/OptionProperties.kt

@@ -50,6 +50,7 @@ open class GlobalOptions(scope: OptionAccessScope) : OptionsPropertiesBase(scope
   var wrapscan: Boolean by optionProperty(Options.wrapscan)
 
   // IdeaVim specific options. Put any editor or IDE specific options in IjOptionProperties
+  var maxhlduringincsearch: Int by optionProperty(Options.maxhlduringincsearch)
 
   // Temporary flags for work-in-progress behaviour. Hidden from the output of `:set all`
   var ideastrictmode: Boolean by optionProperty(Options.ideastrictmode)

vim-engine/src/main/kotlin/com/maddyhome/idea/vim/api/Options.kt

@@ -136,6 +136,7 @@ object Options {
       )
     )
   )
+  val maxhlduringincsearch: NumberOption = addOption(NumberOption(name="maxhlduringincsearch", GLOBAL, "maxhld", 100, -1))
   val maxmapdepth: NumberOption = addOption(NumberOption("maxmapdepth", GLOBAL, "mmd", 20))
   val more: ToggleOption = addOption(ToggleOption("more", GLOBAL, "more", true))
   val nrformats: StringListOption = addOption(