Fix search issue while typing

Fixes #152

m/screenLines.go

@@ -327,24 +327,3 @@ func createLinePrefix(fileLineNumber *int, numberPrefixLength int) []twin.Cell {
 
 	return lineNumberPrefix
 }
-
-// Is the given position visible on screen?
-func (p *Pager) isVisible(scrollPosition scrollPosition) bool {
-	if scrollPosition.lineNumberOneBased(p) < p.lineNumberOneBased() {
-		// It's above the screen, not visible
-		return false
-	}
-
-	lastVisiblePosition := p.getLastVisiblePosition()
-	if scrollPosition.lineNumberOneBased(p) > lastVisiblePosition.lineNumberOneBased(p) {
-		// Line number too high, not visible
-		return false
-	}
-
-	if scrollPosition.deltaScreenLines(p) > lastVisiblePosition.deltaScreenLines(p) {
-		// Sub-line-number too high, not visible
-		return false
-	}
-
-	return true
-}

m/scrollPosition.go

@@ -188,6 +188,33 @@ func (si *scrollPositionInternal) isCanonical(pager *Pager) bool {
 	return false
 }
 
+// Is the given position visible on screen?
+func (sp scrollPosition) isVisible(pager *Pager) bool {
+	if sp.internalDontTouch.deltaScreenLines < 0 {
+		panic(fmt.Errorf("Negative incoming deltaScreenLines: %#v", sp.internalDontTouch))
+	}
+
+	if sp.internalDontTouch.lineNumberOneBased < pager.lineNumberOneBased() {
+		// Line number too low, not visible
+		return false
+	}
+
+	lastVisiblePosition := pager.getLastVisiblePosition()
+	if sp.internalDontTouch.lineNumberOneBased > lastVisiblePosition.lineNumberOneBased(pager) {
+		// Line number too high, not visible
+		return false
+	}
+
+	// Line number is within range, now check the sub-line number
+
+	if sp.internalDontTouch.deltaScreenLines > lastVisiblePosition.deltaScreenLines(pager) {
+		// Sub-line-number too high, not visible
+		return false
+	}
+
+	return true
+}
+
 // Only to be called from the scrollPosition getters!!
 //
 // Canonicalize the scroll position vs the given pager. A canonical position can

m/search.go

@@ -42,7 +42,7 @@ func (p *Pager) scrollToSearchHits() {
 		return
 	}
 
-	if p.isVisible(*firstHitPosition) {
+	if firstHitPosition.isVisible(p) {
 		// Already on-screen, never mind
 		return
 	}

m/search_test.go

@@ -89,3 +89,23 @@ func TestScrollToNextSearchHit_WrapAfterFound(t *testing.T) {
 	assert.Equal(t, _Viewing, pager.mode)
 	assert.Equal(t, 5, pager.lineNumberOneBased())
 }
+
+// Ref: https://github.com/walles/moar/issues/152
+func Test152(t *testing.T) {
+	// Show a pager on a five lines terminal
+	reader := NewReaderFromText("", "a\nab\nabc\nabcd\nabcde\nabcdef\n")
+	screen := twin.NewFakeScreen(20, 5)
+	pager := NewPager(reader)
+	pager.screen = screen
+	assert.Equal(t, _Viewing, pager.mode, "Initial pager state")
+
+	// Search for the first not-visible hit
+	pager.searchString = "abcde"
+	pager.mode = _Searching
+
+	// Scroll to the next search hit
+	pager.updateSearchPattern()
+
+	assert.Equal(t, _Searching, pager.mode)
+	assert.Equal(t, 3, pager.lineNumberOneBased())
+}