Merge branch 'johan/unpause-on-search'

With this change, we now implicitly unpause the reader when the user
is searching.

This enables people finding things in the whole stream, rather than just
finding them in whatever we happen to have in memory right now.

Author: walles

internal/pager.go

@@ -72,7 +72,7 @@ type Pager struct {
 	filter search.Search
 
 	// We used to have a "Following" field here. If you want to follow, set
-	// TargetLineNumber to LineNumberMax() instead, see below.
+	// TargetLineNumber to linemetadata.IndexMax() instead, see below.
 
 	isShowingHelp bool
 	preHelpState  *_PreHelpState
@@ -419,9 +419,8 @@ func (p *Pager) setTargetLine(targetLine *linemetadata.Index) {
 		return
 	}
 
-	// The value 1000 here is supposed to be larger than any possible screen
-	// height, to give us some lookahead and to avoid fetching too few lines.
-	targetValue := targetLine.Index() + 1000
+	// Set the target with some lookahead to avoid fetching too few lines.
+	targetValue := targetLine.Index() + reader.DEFAULT_PAUSE_AFTER_LINES/2
 	if targetValue < targetLine.Index() {
 		// Overflow detected, clip to max int
 		targetValue = math.MaxInt
@@ -620,7 +619,10 @@ func (p *Pager) StartPaging(screen twin.Screen, chromaStyle *chroma.Style, chrom
 			return
 
 		case eventMoreLinesAvailable:
-			if p.TargetLine != nil {
+			// Without the isViewing() check, following will continue while
+			// searching, and I prefer it to stop so people can see what they
+			// are searching in.
+			if p.isViewing() && p.TargetLine != nil {
 				// The user wants to scroll down to a specific line number
 				if linemetadata.IndexFromLength(p.Reader().GetLineCount()).IsBefore(*p.TargetLine) {
 					// Not there yet, keep scrolling

internal/pagermode-filter.go

@@ -45,7 +45,7 @@ func (m *PagerModeFilter) onKey(key twin.KeyCode) {
 	case twin.KeyEscape:
 		m.pager.mode = PagerModeViewing{pager: m.pager}
 		m.pager.filter = search.Search{}
-		m.pager.search.Stop()
+		m.pager.search.Clear()
 
 	case twin.KeyUp, twin.KeyDown, twin.KeyPgUp, twin.KeyPgDown:
 		viewing := PagerModeViewing{pager: m.pager}

internal/pagermode-search.go

@@ -85,16 +85,19 @@ func (m *PagerModeSearch) onKey(key twin.KeyCode) {
 	case twin.KeyEnter:
 		m.pager.searchHistory.addEntry(m.inputBox.text)
 		m.pager.mode = PagerModeViewing{pager: m.pager}
+		m.pager.setTargetLine(nil) // Viewing doesn't need all lines
 
 	case twin.KeyEscape:
 		m.pager.searchHistory.addEntry(m.inputBox.text)
 		m.pager.mode = PagerModeViewing{pager: m.pager}
 		m.pager.scrollPosition = m.initialScrollPosition
+		m.pager.setTargetLine(nil) // Viewing doesn't need all lines
 
 	case twin.KeyPgUp, twin.KeyPgDown:
 		m.pager.searchHistory.addEntry(m.inputBox.text)
 		m.pager.mode = PagerModeViewing{pager: m.pager}
 		m.pager.mode.onKey(key)
+		m.pager.setTargetLine(nil) // Viewing doesn't need all lines
 
 	case twin.KeyUp:
 		m.moveSearchHistoryIndex(-1)

internal/pagermode-viewing.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 
 	log "github.com/sirupsen/logrus"
+	"github.com/walles/moor/v2/internal/linemetadata"
 	"github.com/walles/moor/v2/internal/search"
 	"github.com/walles/moor/v2/internal/textstyles"
 	"github.com/walles/moor/v2/twin"
@@ -162,20 +163,26 @@ func (m PagerModeViewing) onRune(char rune) {
 
 	case '/':
 		p.mode = NewPagerModeSearch(p, SearchDirectionForward, p.scrollPosition)
-		p.setTargetLine(nil)
-		p.search.Stop()
+		p.search.Clear()
+
+		// Searchers want to scan the whole file, start reading as much as we can
+		reallyHigh := linemetadata.IndexMax()
+		p.setTargetLine(&reallyHigh)
 
 	case '?':
 		p.mode = NewPagerModeSearch(p, SearchDirectionBackward, p.scrollPosition)
-		p.setTargetLine(nil)
-		p.search.Stop()
+		p.search.Clear()
+
+		// Searchers want to scan the whole file, start reading as much as we can
+		reallyHigh := linemetadata.IndexMax()
+		p.setTargetLine(&reallyHigh)
 
 	case '&':
 		if !p.isShowingHelp {
 			// Filtering the help text is not supported. Feel free to work on
 			// that if you feel that's time well spent.
 			p.mode = NewPagerModeFilter(p)
-			p.search.Stop()
+			p.search.Clear()
 			p.filter = search.Search{}
 		}
 

internal/reader/reader.go

@@ -30,9 +30,12 @@ import (
 // negotiable.
 const MAX_HIGHLIGHT_SIZE int64 = 2_000_000
 
-// 140k lines took 20ms to search from a cold start. If we want to stay below
-// 100ms, we can do about 700k lines before pausing.
-const DEFAULT_PAUSE_AFTER_LINES = 700_000
+// To cap resource usage when not needed, start by reading this many lines into
+// memory. If the user scrolls near the end or starts searching, we'll read
+// more.
+//
+// Ref: https://github.com/walles/moor/issues/296
+const DEFAULT_PAUSE_AFTER_LINES = 50_000
 
 var DisablePlainCachingForBenchmarking = false
 

internal/search/search.go

@@ -73,7 +73,7 @@ func (search *Search) For(s string) *Search {
 	return search
 }
 
-func (search *Search) Stop() {
+func (search *Search) Clear() {
 	search.findMe = ""
 	search.pattern = nil
 }