Simplify split diff view generation and remove JS dependency (#16775)

Gitea has relied on some slow JS code to match up added and deleted lines on the diff pages. This can cause a considerable slow down on large diff pages. This PR makes a small change meaning that the matching up can occur much more simply. Partial fix #1351

zeripath committed 5 years ago

Commit f5b0e2c1 parent d24eb6e4 files · +109 −75Browse files

Showing the changes to services/gitdiff/gitdiff.go (1 of 4 files). Show all

Unified · Split

services/gitdiff/gitdiff.go+16−2

 type DiffLine struct {
 	LeftIdx     int
 	RightIdx    int
+	Match       int
 	Type        DiffLineType
 	Content     string
 	Comments    []*models.Comment
 		curFileLFSPrefix  bool
 	)
+	lastLeftIdx := -1
 	leftLine, rightLine := 1, 1
 	for {
 				curFile.IsIncomplete = true
 				continue
 			}
-			diffLine := &DiffLine{Type: DiffLineAdd, RightIdx: rightLine}
+			diffLine := &DiffLine{Type: DiffLineAdd, RightIdx: rightLine, Match: -1}
 			rightLine++
 			if curSection == nil {
 				// Create a new section to represent this hunk
 				curSection = &DiffSection{}
 				curFile.Sections = append(curFile.Sections, curSection)
 			}
+			if lastLeftIdx > -1 {
+				diffLine.Match = lastLeftIdx
+				curSection.Lines[lastLeftIdx].Match = len(curSection.Lines)
+				lastLeftIdx++
+				if lastLeftIdx >= len(curSection.Lines) || curSection.Lines[lastLeftIdx].Type != DiffLineDel {
+					lastLeftIdx = -1
+				}
+			}
 			curSection.Lines = append(curSection.Lines, diffLine)
 		case '-':
 			curFileLinesCount++
 				curFile.IsIncomplete = true
 				continue
 			}
-			diffLine := &DiffLine{Type: DiffLineDel, LeftIdx: leftLine}
+			diffLine := &DiffLine{Type: DiffLineDel, LeftIdx: leftLine, Match: -1}
 			if leftLine > 0 {
 				leftLine++
 			}
 				curSection = &DiffSection{}
 				curFile.Sections = append(curFile.Sections, curSection)
 			}
+			if len(curSection.Lines) == 0 || curSection.Lines[len(curSection.Lines)-1].Type != DiffLineDel {
+				lastLeftIdx = len(curSection.Lines)
+			}
 			curSection.Lines = append(curSection.Lines, diffLine)
 		case ' ':
 			curFileLinesCount++
 			diffLine := &DiffLine{Type: DiffLinePlain, LeftIdx: leftLine, RightIdx: rightLine}
 			leftLine++
 			rightLine++
+			lastLeftIdx = -1
 			if curSection == nil {
 				// Create a new section to represent this hunk
 				curSection = &DiffSection{}