package patch import ( "fmt" "regexp" "strings" "github.com/sirupsen/logrus" ) var hunkHeaderRegexp = regexp.MustCompile(`(?m)^@@ -(\d+)[^\+]+\+(\d+)[^@]+@@(.*)$`) var patchHeaderRegexp = regexp.MustCompile(`(?ms)(^diff.*?)^@@`) func GetHeaderFromDiff(diff string) string { match := patchHeaderRegexp.FindStringSubmatch(diff) if len(match) <= 1 { return "" } return match[1] } func GetHunksFromDiff(diff string) []*PatchHunk { hunks := []*PatchHunk{} firstLineIdx := -1 var hunkLines []string pastDiffHeader := false for lineIdx, line := range strings.SplitAfter(diff, "\n") { isHunkHeader := strings.HasPrefix(line, "@@ -") if isHunkHeader { if pastDiffHeader { // we need to persist the current hunk hunks = append(hunks, newHunk(hunkLines, firstLineIdx)) } pastDiffHeader = true firstLineIdx = lineIdx hunkLines = []string{line} continue } if !pastDiffHeader { // skip through the stuff that precedes the first hunk continue } hunkLines = append(hunkLines, line) } if pastDiffHeader { hunks = append(hunks, newHunk(hunkLines, firstLineIdx)) } return hunks } type PatchModifier struct { Log *logrus.Entry filename string hunks []*PatchHunk header string } func NewPatchModifier(log *logrus.Entry, filename string, diffText string) *PatchModifier { return &PatchModifier{ Log: log, filename: filename, hunks: GetHunksFromDiff(diffText), header: GetHeaderFromDiff(diffText), } } func (d *PatchModifier) ModifiedPatchForLines(lineIndices []int, reverse bool, keepOriginalHeader bool) string { // step one is getting only those hunks which we care about hunksInRange := []*PatchHunk{} outer: for _, hunk := range d.hunks { // if there is any line in our lineIndices array that the hunk contains, we append it for _, lineIdx := range lineIndices { if lineIdx >= hunk.FirstLineIdx && lineIdx <= hunk.LastLineIdx() { hunksInRange = append(hunksInRange, hunk) continue outer } } } // step 2 is collecting all the hunks with new headers startOffset := 0 formattedHunks := "" var formattedHunk string for _, hunk := range hunksInRange { startOffset, formattedHunk = hunk.formatWithChanges(lineIndices, reverse, startOffset) formattedHunks += formattedHunk } if formattedHunks == "" { return "" } var fileHeader string // for staging/unstaging lines we don't want the original header because // it makes git confused e.g. when dealing with deleted/added files // but with building and applying patches the original header gives git // information it needs to cleanly apply patches if keepOriginalHeader { fileHeader = d.header } else { fileHeader = fmt.Sprintf("--- a/%s\n+++ b/%s\n", d.filename, d.filename) } return fileHeader + formattedHunks } func (d *PatchModifier) ModifiedPatchForRange(firstLineIdx int, lastLineIdx int, reverse bool, keepOriginalHeader bool) string { // generate array of consecutive line indices from our range selectedLines := []int{} for i := firstLineIdx; i <= lastLineIdx; i++ { selectedLines = append(selectedLines, i) } return d.ModifiedPatchForLines(selectedLines, reverse, keepOriginalHeader) } func (d *PatchModifier) OriginalPatchLength() int { if len(d.hunks) == 0 { return 0 } return d.hunks[len(d.hunks)-1].LastLineIdx() } func ModifiedPatchForRange(log *logrus.Entry, filename string, diffText string, firstLineIdx int, lastLineIdx int, reverse bool, keepOriginalHeader bool) string { p := NewPatchModifier(log, filename, diffText) return p.ModifiedPatchForRange(firstLineIdx, lastLineIdx, reverse, keepOriginalHeader) } func ModifiedPatchForLines(log *logrus.Entry, filename string, diffText string, includedLineIndices []int, reverse bool, keepOriginalHeader bool) string { p := NewPatchModifier(log, filename, diffText) return p.ModifiedPatchForLines(includedLineIndices, reverse, keepOriginalHeader) } // I want to know, given a hunk, what line a given index is on func (hunk *PatchHunk) LineNumberOfLine(idx int) int { n := idx - hunk.FirstLineIdx - 1 if n < 0 { n = 0 } else if n >= len(hunk.bodyLines) { n = len(hunk.bodyLines) - 1 } lines := hunk.bodyLines[0:n] offset := nLinesWithPrefix(lines, []string{"+", " "}) return hunk.newStart + offset } func nLinesWithPrefix(lines []string, chars []string) int { result := 0 for _, line := range lines { for _, char := range chars { if line[:1] == char { result++ } } } return result }