From 47aa61ceab94327e4f178ee18d93163e07b9e403 Mon Sep 17 00:00:00 2001
From: Jason Fields <jasonfields4@gmail.com>
Date: Mon, 27 Jun 2022 18:48:57 -0400
Subject: [PATCH] Cache search decorations when possible

This actually saves a *lot* of work on simple keystrokes like `hjkl` when you've got a lot of search results highlighted.
---
 src/mode/modeHandler.ts     | 27 ++++++++++++++++++++++++---
 src/util/decorationUtils.ts |  8 ++------
 2 files changed, 26 insertions(+), 9 deletions(-)

diff --git a/src/mode/modeHandler.ts b/src/mode/modeHandler.ts
index 6fde97aeb..29dbe5819 100644
--- a/src/mode/modeHandler.ts
+++ b/src/mode/modeHandler.ts
@@ -17,7 +17,7 @@ import { PairMatcher } from './../common/matching/matcher';
 import { laterOf } from './../common/motion/position';
 import { Cursor } from '../common/motion/cursor';
 import { RecordedState } from './../state/recordedState';
-import { IBaseAction } from "../actions/types";
+import { IBaseAction } from '../actions/types';
 import { Register, RegisterMode } from './../register/register';
 import { Remappers } from '../configuration/remapper';
 import { StatusBar } from '../statusBar';
@@ -46,6 +46,7 @@ import { Position, Uri } from 'vscode';
 import { RemapState } from '../state/remapState';
 import * as process from 'process';
 import { EasyMotion } from '../actions/plugins/easymotion/easymotion';
+import { SearchState } from '../state/searchState';
 
 interface IModeHandlerMap {
   get(editorId: Uri): ModeHandler | undefined;
@@ -63,6 +64,10 @@ export class ModeHandler implements vscode.Disposable, IModeHandler {
 
   public focusChanged = false;
 
+  private searchDecorationCacheKey:
+    | { searchState: SearchState; documentVersion: number }
+    | undefined;
+
   private readonly disposables: vscode.Disposable[] = [];
   private readonly handlerMap: IModeHandlerMap;
   private readonly remappers: Remappers;
@@ -1156,6 +1161,9 @@ export class ModeHandler implements vscode.Disposable, IModeHandler {
   }
 
   public updateSearchHighlights(showHighlights: boolean) {
+    const cacheKey = this.searchDecorationCacheKey;
+    this.searchDecorationCacheKey = undefined;
+
     let decorations: SearchDecorations | undefined;
     if (showHighlights) {
       if (
@@ -1163,11 +1171,24 @@ export class ModeHandler implements vscode.Disposable, IModeHandler {
         this.vimState.modeData.mode === Mode.SearchInProgressMode
       ) {
         decorations = this.vimState.modeData.commandLine.getDecorations(this.vimState);
-      } else {
+      } else if (globalState.searchState) {
+        if (
+          cacheKey &&
+          cacheKey.searchState === globalState.searchState &&
+          cacheKey.documentVersion === this.vimState.document.version
+        ) {
+          // The decorations are fine as-is, don't waste time re-calculating
+          this.searchDecorationCacheKey = cacheKey;
+          return;
+        }
         // If there are no decorations from the command line, get decorations for previous SearchState
         decorations = getDecorationsForSearchMatchRanges(
-          globalState.searchState?.getMatchRanges(this.vimState)
+          globalState.searchState.getMatchRanges(this.vimState)
         );
+        this.searchDecorationCacheKey = {
+          searchState: globalState.searchState,
+          documentVersion: this.vimState.document.version,
+        };
       }
     }
 
diff --git a/src/util/decorationUtils.ts b/src/util/decorationUtils.ts
index 5f51bb85c..3990d5109 100644
--- a/src/util/decorationUtils.ts
+++ b/src/util/decorationUtils.ts
@@ -24,7 +24,7 @@ export type SearchDecorations = {
  * character.
  */
 export function ensureVisible(range: Range): DecorationOptions {
-  return range.start.isLineEnd() && (range.isEmpty || range.end.isLineBeginning())
+  return (range.isEmpty || range.end.isLineBeginning()) && range.start.isLineEnd()
     ? {
         // range is at EOL, possibly containing EOL char(s).
         range: range.with(undefined, range.start),
@@ -61,13 +61,9 @@ export function formatDecorationText(
  * @returns search decorations for the given ranges, taking into account the current match
  */
 export function getDecorationsForSearchMatchRanges(
-  ranges: Range[] | undefined,
+  ranges: Range[],
   currentMatchIndex?: number
 ): SearchDecorations {
-  if (ranges === undefined) {
-    return {};
-  }
-
   const searchHighlight: DecorationOptions[] = [];
   const searchMatch: DecorationOptions[] = [];