From edb3e51680fe34347552b52501fbeb65fbc11c29 Mon Sep 17 00:00:00 2001
From: Johan Walles <johan.walles@gmail.com>
Date: Mon, 13 May 2024 07:59:40 +0200
Subject: [PATCH] Don't search the whole file more than once

Should improve the performance situation reported here:
https://github.com/walles/moar/issues/209
---
 m/pager_test.go | 10 +++++-----
 m/search.go     | 15 ++++++++++-----
 2 files changed, 15 insertions(+), 10 deletions(-)

diff --git a/m/pager_test.go b/m/pager_test.go
index 6ecbbd6..c3a6790 100644
--- a/m/pager_test.go
+++ b/m/pager_test.go
@@ -298,7 +298,7 @@ func TestFindFirstHitSimple(t *testing.T) {
 
 	pager.searchPattern = toPattern("AB")
 
-	hit := pager.findFirstHit(linenumbers.LineNumber{}, false)
+	hit := pager.findFirstHit(linenumbers.LineNumber{}, nil, false)
 	assert.Assert(t, hit.internalDontTouch.lineNumber.IsZero())
 	assert.Equal(t, hit.internalDontTouch.deltaScreenLines, 0)
 }
@@ -312,7 +312,7 @@ func TestFindFirstHitAnsi(t *testing.T) {
 
 	pager.searchPattern = toPattern("AB")
 
-	hit := pager.findFirstHit(linenumbers.LineNumber{}, false)
+	hit := pager.findFirstHit(linenumbers.LineNumber{}, nil, false)
 	assert.Assert(t, hit.internalDontTouch.lineNumber.IsZero())
 	assert.Equal(t, hit.internalDontTouch.deltaScreenLines, 0)
 }
@@ -326,7 +326,7 @@ func TestFindFirstHitNoMatch(t *testing.T) {
 
 	pager.searchPattern = toPattern("this pattern should not be found")
 
-	hit := pager.findFirstHit(linenumbers.LineNumber{}, false)
+	hit := pager.findFirstHit(linenumbers.LineNumber{}, nil, false)
 	assert.Assert(t, hit == nil)
 }
 
@@ -340,7 +340,7 @@ func TestFindFirstHitNoMatchBackwards(t *testing.T) {
 	pager.searchPattern = toPattern("this pattern should not be found")
 	theEnd := *linenumbers.LineNumberFromLength(reader.GetLineCount())
 
-	hit := pager.findFirstHit(theEnd, true)
+	hit := pager.findFirstHit(theEnd, nil, true)
 	assert.Assert(t, hit == nil)
 }
 
@@ -682,7 +682,7 @@ func benchmarkSearch(b *testing.B, highlighted bool) {
 	b.ResetTimer()
 
 	// This test will search through all the N copies we made of our file
-	hit := pager.findFirstHit(linenumbers.LineNumber{}, false)
+	hit := pager.findFirstHit(linenumbers.LineNumber{}, nil, false)
 
 	if hit != nil {
 		panic(fmt.Errorf("This test is meant to scan the whole file without finding anything"))
diff --git a/m/search.go b/m/search.go
index 3a8fef8..d61e51b 100644
--- a/m/search.go
+++ b/m/search.go
@@ -12,10 +12,10 @@ func (p *Pager) scrollToSearchHits() {
 		return
 	}
 
-	firstHitPosition := p.findFirstHit(*p.scrollPosition.lineNumber(p), false)
+	firstHitPosition := p.findFirstHit(*p.scrollPosition.lineNumber(p), nil, false)
 	if firstHitPosition == nil {
 		// Try again from the top
-		firstHitPosition = p.findFirstHit(linenumbers.LineNumber{}, false)
+		firstHitPosition = p.findFirstHit(linenumbers.LineNumber{}, p.scrollPosition.lineNumber(p), false)
 	}
 	if firstHitPosition == nil {
 		// No match, give up
@@ -35,7 +35,7 @@ func (p *Pager) scrollToSearchHits() {
 // scrollPosition for searching.
 //
 // FIXME: We should take startPosition.deltaScreenLines into account as well!
-func (p *Pager) findFirstHit(startPosition linenumbers.LineNumber, backwards bool) *scrollPosition {
+func (p *Pager) findFirstHit(startPosition linenumbers.LineNumber, beforePosition *linenumbers.LineNumber, backwards bool) *scrollPosition {
 	searchPosition := startPosition
 	for {
 		line := p.reader.GetLine(searchPosition)
@@ -58,6 +58,11 @@ func (p *Pager) findFirstHit(startPosition linenumbers.LineNumber, backwards boo
 			searchPosition = searchPosition.NonWrappingAdd(-1)
 		} else {
 			searchPosition = searchPosition.NonWrappingAdd(1)
+
+			if beforePosition != nil && searchPosition == *beforePosition {
+				// No match, give up
+				return nil
+			}
 		}
 	}
 }
@@ -105,7 +110,7 @@ func (p *Pager) scrollToNextSearchHit() {
 		panic(fmt.Sprint("Unknown search mode when finding next: ", p.mode))
 	}
 
-	firstHitPosition := p.findFirstHit(firstSearchPosition, false)
+	firstHitPosition := p.findFirstHit(firstSearchPosition, nil, false)
 	if firstHitPosition == nil {
 		p.mode = PagerModeNotFound{pager: p}
 		return
@@ -144,7 +149,7 @@ func (p *Pager) scrollToPreviousSearchHit() {
 		panic(fmt.Sprint("Unknown search mode when finding previous: ", p.mode))
 	}
 
-	firstHitPosition := p.findFirstHit(firstSearchPosition, true)
+	firstHitPosition := p.findFirstHit(firstSearchPosition, nil, true)
 	if firstHitPosition == nil {
 		p.mode = PagerModeNotFound{pager: p}
 		return