Add gerrit widget

vendor/github.com/rivo/tview/textview.go

@@ -104,6 +104,10 @@ type TextView struct {
 	// during re-indexing. Set to -1 if there is no current highlight.
 	fromHighlight, toHighlight int
 
+	// The screen space column of the highlight in its first line. Set to -1 if
+	// there is no current highlight.
+	posHighlight int
+
 	// A set of region IDs that are currently highlighted.
 	highlights map[string]struct{}
 
@@ -171,6 +175,7 @@ func NewTextView() *TextView {
 		align:         AlignLeft,
 		wrap:          true,
 		textColor:     Styles.PrimaryTextColor,
+		regions:       false,
 		dynamicColors: false,
 	}
 }
@@ -503,7 +508,7 @@ func (t *TextView) reindexBuffer(width int) {
 		return // Nothing has changed. We can still use the current index.
 	}
 	t.index = nil
-	t.fromHighlight, t.toHighlight = -1, -1
+	t.fromHighlight, t.toHighlight, t.posHighlight = -1, -1, -1
 
 	// If there's no space, there's no index.
 	if width < 1 {
@@ -522,8 +527,9 @@ func (t *TextView) reindexBuffer(width int) {
 			colorTags       [][]string
 			escapeIndices   [][]int
 		)
+		strippedStr := str
 		if t.dynamicColors {
-			colorTagIndices, colorTags, escapeIndices, str, _ = decomposeString(str)
+			colorTagIndices, colorTags, escapeIndices, strippedStr, _ = decomposeString(str)
 		}
 
 		// Find all regions in this line. Then remove them.
@@ -534,14 +540,18 @@ func (t *TextView) reindexBuffer(width int) {
 		if t.regions {
 			regionIndices = regionPattern.FindAllStringIndex(str, -1)
 			regions = regionPattern.FindAllStringSubmatch(str, -1)
-			str = regionPattern.ReplaceAllString(str, "")
-			if !t.dynamicColors {
-				// We haven't detected escape tags yet. Do it now.
-				escapeIndices = escapePattern.FindAllStringIndex(str, -1)
-				str = escapePattern.ReplaceAllString(str, "[$1$2]")
-			}
+			strippedStr = regionPattern.ReplaceAllString(strippedStr, "")
 		}
 
+		// Find all escape tags in this line. Escape them.
+		if t.dynamicColors || t.regions {
+			escapeIndices = escapePattern.FindAllStringIndex(str, -1)
+			strippedStr = escapePattern.ReplaceAllString(strippedStr, "[$1$2]")
+		}
+
+		// We don't need the original string anymore for now.
+		str = strippedStr
+
 		// Split the line if required.
 		var splitLines []string
 		if t.wrap && len(str) > 0 {
@@ -585,15 +595,53 @@ func (t *TextView) reindexBuffer(width int) {
 
 			// Shift original position with tags.
 			lineLength := len(splitLine)
+			remainingLength := lineLength
+			tagEnd := originalPos
+			totalTagLength := 0
 			for {
-				if colorPos < len(colorTagIndices) && colorTagIndices[colorPos][0] <= originalPos+lineLength {
+				// Which tag comes next?
+				nextTag := make([][3]int, 0, 3)
+				if colorPos < len(colorTagIndices) {
+					nextTag = append(nextTag, [3]int{colorTagIndices[colorPos][0], colorTagIndices[colorPos][1], 0}) // 0 = color tag.
+				}
+				if regionPos < len(regionIndices) {
+					nextTag = append(nextTag, [3]int{regionIndices[regionPos][0], regionIndices[regionPos][1], 1}) // 1 = region tag.
+				}
+				if escapePos < len(escapeIndices) {
+					nextTag = append(nextTag, [3]int{escapeIndices[escapePos][0], escapeIndices[escapePos][1], 2}) // 2 = escape tag.
+				}
+				minPos := -1
+				tagIndex := -1
+				for index, pair := range nextTag {
+					if minPos < 0 || pair[0] < minPos {
+						minPos = pair[0]
+						tagIndex = index
+					}
+				}
+
+				// Is the next tag in range?
+				if tagIndex < 0 || minPos >= tagEnd+remainingLength {
+					break // No. We're done with this line.
+				}
+
+				// Advance.
+				strippedTagStart := nextTag[tagIndex][0] - originalPos - totalTagLength
+				tagEnd = nextTag[tagIndex][1]
+				tagLength := tagEnd - nextTag[tagIndex][0]
+				if nextTag[tagIndex][2] == 2 {
+					tagLength = 1
+				}
+				totalTagLength += tagLength
+				remainingLength = lineLength - (tagEnd - originalPos - totalTagLength)
+
+				// Process the tag.
+				switch nextTag[tagIndex][2] {
+				case 0:
 					// Process color tags.
-					originalPos += colorTagIndices[colorPos][1] - colorTagIndices[colorPos][0]
 					foregroundColor, backgroundColor, attributes = styleFromTag(foregroundColor, backgroundColor, attributes, colorTags[colorPos])
 					colorPos++
-				} else if regionPos < len(regionIndices) && regionIndices[regionPos][0] <= originalPos+lineLength {
+				case 1:
 					// Process region tags.
-					originalPos += regionIndices[regionPos][1] - regionIndices[regionPos][0]
 					regionID = regions[regionPos][1]
 					_, highlighted = t.highlights[regionID]
 
@@ -602,23 +650,21 @@ func (t *TextView) reindexBuffer(width int) {
 						line := len(t.index)
 						if t.fromHighlight < 0 {
 							t.fromHighlight, t.toHighlight = line, line
+							t.posHighlight = runewidth.StringWidth(splitLine[:strippedTagStart])
 						} else if line > t.toHighlight {
 							t.toHighlight = line
 						}
 					}
 
 					regionPos++
-				} else if escapePos < len(escapeIndices) && escapeIndices[escapePos][0] <= originalPos+lineLength {
+				case 2:
 					// Process escape tags.
-					originalPos++
 					escapePos++
-				} else {
-					break
 				}
 			}
 
 			// Advance to next line.
-			originalPos += lineLength
+			originalPos += lineLength + totalTagLength
 
 			// Append this line.
 			line.NextPos = originalPos
@@ -683,6 +729,16 @@ func (t *TextView) Draw(screen tcell.Screen) {
 			// No, let's move to the start of the highlights.
 			t.lineOffset = t.fromHighlight
 		}
+
+		// If the highlight is too far to the right, move it to the middle.
+		if t.posHighlight-t.columnOffset > 3*width/4 {
+			t.columnOffset = t.posHighlight - width/2
+		}
+
+		// If the highlight is off-screen on the left, move it on-screen.
+		if t.posHighlight-t.columnOffset < 0 {
+			t.columnOffset = t.posHighlight - width/4
+		}
 	}
 	t.scrollToHighlights = false