highlighter: Reintroduction of statesOnly to fix bottom up changes

This regression was introduced by accident in the moment the highlighting
interfaces have been combined. The MarkModified() method of the buffer
wasn't able to highlight bottom up changes lines in the backward direction.

Author: JoeKar

internal/buffer/buffer.go

@@ -150,9 +150,11 @@ func (b *SharedBuffer) MarkModified(start, end int) {
 	end = util.Clamp(end, 0, len(b.lines)-1)
 
 	if b.Settings["syntax"].(bool) && b.SyntaxDef != nil {
+		l := start
 		for i := start; i <= end; i++ {
-			b.Highlighter.Highlight(b, start, end)
+			l = util.Max(b.Highlighter.Highlight(b, i, end, true), l)
 		}
+		b.Highlighter.Highlight(b, start, l, false)
 	}
 
 	for i := start; i <= end; i++ {
@@ -817,7 +819,7 @@ func (b *Buffer) UpdateRules() {
 		b.Highlighter = highlight.NewHighlighter(b.SyntaxDef)
 		if b.Settings["syntax"].(bool) {
 			go func() {
-				b.Highlighter.Highlight(b, 0, b.End().Y)
+				b.Highlighter.Highlight(b, 0, b.End().Y, false)
 				screen.Redraw()
 			}()
 		}

pkg/highlight/highlighter.go

@@ -91,7 +91,11 @@ func findAllIndex(regex *regexp.Regexp, skip *regexp.Regexp, str []byte) [][]int
 	return matches
 }
 
-func (h *Highlighter) highlightRange(fullHighlights []Group, start int, end int, group Group) {
+func (h *Highlighter) highlightRange(fullHighlights []Group, start int, end int, group Group, statesOnly bool) {
+	if statesOnly {
+		return
+	}
+
 	if start <= end && end <= len(fullHighlights) {
 		for i := start; i < end; i++ {
 			fullHighlights[i] = group
@@ -100,10 +104,10 @@ func (h *Highlighter) highlightRange(fullHighlights []Group, start int, end int,
 	}
 }
 
-func (h *Highlighter) highlightPatterns(fullHighlights []Group, start int, lineNum int, line []byte, curRegion *region) {
+func (h *Highlighter) highlightPatterns(fullHighlights []Group, start int, lineNum int, line []byte, curRegion *region, statesOnly bool) {
 	lineLen := util.CharacterCount(line)
 	// log.Println("highlightPatterns: lineNum:", lineNum, "start:", start, "line:", string(line))
-	if lineLen == 0 {
+	if lineLen == 0 || statesOnly {
 		return
 	}
 
@@ -118,20 +122,20 @@ func (h *Highlighter) highlightPatterns(fullHighlights []Group, start int, lineN
 		if curRegion == nil || curRegion.group == curRegion.limitGroup || p.group == curRegion.limitGroup {
 			matches := findAllIndex(p.regex, nil, line)
 			for _, m := range matches {
-				h.highlightRange(fullHighlights, start+m[0], start+m[1], p.group)
+				h.highlightRange(fullHighlights, start+m[0], start+m[1], p.group, statesOnly)
 			}
 		}
 	}
 }
 
-func (h *Highlighter) highlightRegions(fullHighlights []Group, start int, lineNum int, line []byte, curRegion *region, regions []*region, nestedRegion bool) {
+func (h *Highlighter) highlightRegions(fullHighlights []Group, start int, lineNum int, line []byte, curRegion *region, regions []*region, nestedRegion bool, statesOnly bool) {
 	lineLen := util.CharacterCount(line)
 	// log.Println("highlightRegions: lineNum:", lineNum, "start:", start, "line:", string(line))
 	if lineLen == 0 {
 		return
 	}
 
-	h.highlightPatterns(fullHighlights, start, lineNum, line, curRegion)
+	h.highlightPatterns(fullHighlights, start, lineNum, line, curRegion, statesOnly)
 
 	lastStart := 0
 	regionStart := 0
@@ -176,8 +180,8 @@ func (h *Highlighter) highlightRegions(fullHighlights []Group, start int, lineNu
 						// log.Println("start < end")
 						regionStart = startMatches[startIdx][0]
 						regionEnd = endMatches[endIdx][1]
-						h.highlightRange(fullHighlights, start+startMatches[startIdx][0], start+endMatches[endIdx][1], r.limitGroup)
-						h.highlightRegions(fullHighlights, start+startMatches[startIdx][1], lineNum, util.SliceStartEnd(line, startMatches[startIdx][1], endMatches[endIdx][0]), r, r.rules.regions, true)
+						h.highlightRange(fullHighlights, start+startMatches[startIdx][0], start+endMatches[endIdx][1], r.limitGroup, statesOnly)
+						h.highlightRegions(fullHighlights, start+startMatches[startIdx][1], lineNum, util.SliceStartEnd(line, startMatches[startIdx][1], endMatches[endIdx][0]), r, r.rules.regions, true, statesOnly)
 						if samePattern {
 							startIdx += 1
 						}
@@ -196,9 +200,9 @@ func (h *Highlighter) highlightRegions(fullHighlights []Group, start int, lineNu
 						}
 						// start and end at the current line, but switched
 						// log.Println("end < start")
-						h.highlightRange(fullHighlights, start, start+endMatches[endIdx][1], r.limitGroup)
-						h.highlightRegions(fullHighlights, start, lineNum, util.SliceStart(line, endMatches[endIdx][0]), r, r.rules.regions, true)
-						h.highlightPatterns(fullHighlights, start+endMatches[endIdx][1], lineNum, util.SliceStartEnd(line, endMatches[endIdx][1], startMatches[startIdx][0]), nil)
+						h.highlightRange(fullHighlights, start, start+endMatches[endIdx][1], r.limitGroup, statesOnly)
+						h.highlightRegions(fullHighlights, start, lineNum, util.SliceStart(line, endMatches[endIdx][0]), r, r.rules.regions, true, statesOnly)
+						h.highlightPatterns(fullHighlights, start+endMatches[endIdx][1], lineNum, util.SliceStartEnd(line, endMatches[endIdx][1], startMatches[startIdx][0]), nil, statesOnly)
 						if curRegion != nil {
 							h.lastRegion = curRegion.parent
 						} else {
@@ -212,8 +216,8 @@ func (h *Highlighter) highlightRegions(fullHighlights []Group, start int, lineNu
 					// log.Println("start ...")
 					regionStart = startMatches[startIdx][0]
 					regionEnd = 0
-					h.highlightRange(fullHighlights, start+startMatches[startIdx][0], lineLen, r.limitGroup)
-					h.highlightRegions(fullHighlights, start+startMatches[startIdx][1], lineNum, util.SliceEnd(line, startMatches[startIdx][1]), r, r.rules.regions, true)
+					h.highlightRange(fullHighlights, start+startMatches[startIdx][0], lineLen, r.limitGroup, statesOnly)
+					h.highlightRegions(fullHighlights, start+startMatches[startIdx][1], lineNum, util.SliceEnd(line, startMatches[startIdx][1]), r, r.rules.regions, true, statesOnly)
 					if lastStart <= startMatches[startIdx][0] {
 						lastStart = startMatches[startIdx][0]
 						h.lastRegion = r
@@ -226,8 +230,8 @@ func (h *Highlighter) highlightRegions(fullHighlights []Group, start int, lineNu
 				for _, endMatch := range endMatches {
 					// end at the current, but start at the previous line
 					// log.Println("... end")
-					h.highlightRange(fullHighlights, start, start+endMatch[1], r.limitGroup)
-					h.highlightRegions(fullHighlights, start, lineNum, util.SliceStart(line, endMatch[0]), r, r.rules.regions, true)
+					h.highlightRange(fullHighlights, start, start+endMatch[1], r.limitGroup, statesOnly)
+					h.highlightRegions(fullHighlights, start, lineNum, util.SliceStart(line, endMatch[0]), r, r.rules.regions, true, statesOnly)
 					if curRegion != nil {
 						h.lastRegion = curRegion.parent
 					} else {
@@ -238,25 +242,27 @@ func (h *Highlighter) highlightRegions(fullHighlights []Group, start int, lineNu
 				}
 			} else if len(startMatches) == 0 && len(endMatches) == 0 {
 				// no start and end found in this region
-				h.highlightRange(fullHighlights, start, lineLen, curRegion.group)
+				h.highlightRange(fullHighlights, start, lineLen, curRegion.group, statesOnly)
 			}
 		}
 	}
 }
 
-func (h *Highlighter) highlight(highlights LineMatch, start int, lineNum int, line []byte, curRegion *region) LineMatch {
+func (h *Highlighter) highlight(highlights LineMatch, start int, lineNum int, line []byte, curRegion *region, statesOnly bool) LineMatch {
 	lineLen := util.CharacterCount(line)
 	// log.Println("highlight: lineNum:", lineNum, "start:", start, "line:", string(line))
 	if lineLen == 0 {
 		return highlights
 	}
 
 	fullHighlights := make([]Group, lineLen)
-	h.highlightRegions(fullHighlights, start, lineNum, line, curRegion, h.Def.rules.regions, false)
+	h.highlightRegions(fullHighlights, start, lineNum, line, curRegion, h.Def.rules.regions, false, statesOnly)
 
-	for i, h := range fullHighlights {
-		if i == 0 || h != fullHighlights[i-1] {
-			highlights[i] = h
+	if !statesOnly {
+		for i, h := range fullHighlights {
+			if i == 0 || h != fullHighlights[i-1] {
+				highlights[i] = h
+			}
 		}
 	}
 
@@ -274,20 +280,28 @@ func (h *Highlighter) HighlightString(input string) []LineMatch {
 	for i := 0; i < len(lines); i++ {
 		line := []byte(lines[i])
 		highlights := make(LineMatch)
-		lineMatches = append(lineMatches, h.highlight(highlights, 0, i, line, nil))
+		lineMatches = append(lineMatches, h.highlight(highlights, 0, i, line, nil, false))
 	}
 
 	return lineMatches
 }
 
 // Highlight sets the state and matches for each line from startline to endline
 // It sets all other matches in the buffer to nil to conserve memory
-func (h *Highlighter) Highlight(input LineStates, startline, endline int) {
+// In the moment it is called with statesOnly set it will scan down from
+// `startline` and set the appropriate end of line state for each line
+// until it comes across a line whose state does not change
+// returns the number of the final line
+func (h *Highlighter) Highlight(input LineStates, startline, endline int, statesOnly bool) int {
 	h.lastRegion = nil
 	if startline > 0 {
 		h.lastRegion = input.State(startline - 1)
 	}
 
+	if statesOnly {
+		endline = input.LinesNum() - 1
+	}
+
 	for i := startline; i <= endline; i++ {
 		if i >= input.LinesNum() {
 			break
@@ -297,11 +311,23 @@ func (h *Highlighter) Highlight(input LineStates, startline, endline int) {
 		highlights := make(LineMatch)
 
 		var match LineMatch
-		match = h.highlight(highlights, 0, i, line, h.lastRegion)
+		match = h.highlight(highlights, 0, i, line, h.lastRegion, statesOnly)
 
-		input.SetState(i, h.lastRegion)
-		input.SetMatch(i, match)
+		curState := h.lastRegion
+		lastState := input.State(i)
+
+		input.SetState(i, curState)
+
+		if !statesOnly {
+			input.SetMatch(i, match)
+		} else {
+			if curState == lastState {
+				return i
+			}
+		}
 	}
+
+	return input.LinesNum() - 1
 }
 
 // ReHighlightLine will rehighlight the state and match for a single line
@@ -315,7 +341,7 @@ func (h *Highlighter) ReHighlightLine(input LineStates, lineN int) {
 	}
 
 	var match LineMatch
-	match = h.highlight(highlights, 0, lineN, line, h.lastRegion)
+	match = h.highlight(highlights, 0, lineN, line, h.lastRegion, false)
 
 	input.SetState(lineN, h.lastRegion)
 	input.SetMatch(lineN, match)