package object
import (
"bytes"
"context"
"errors"
"fmt"
"io"
"strconv"
"strings"
"github.com/go-git/go-git/v5/plumbing"
"github.com/go-git/go-git/v5/plumbing/filemode"
fdiff "github.com/go-git/go-git/v5/plumbing/format/diff"
"github.com/go-git/go-git/v5/utils/diff"
dmp "github.com/sergi/go-diff/diffmatchpatch"
)
var (
ErrCanceled = errors.New("operation canceled")
)
func getPatch(message string, changes ...*Change) (*Patch, error) {
ctx := context.Background()
return getPatchContext(ctx, message, changes...)
}
func getPatchContext(ctx context.Context, message string, changes ...*Change) (*Patch, error) {
var filePatches []fdiff.FilePatch
for _, c := range changes {
select {
case <-ctx.Done():
return nil, ErrCanceled
default:
}
fp, err := filePatchWithContext(ctx, c)
if err != nil {
return nil, err
}
filePatches = append(filePatches, fp)
}
return &Patch{message, filePatches}, nil
}
func filePatchWithContext(ctx context.Context, c *Change) (fdiff.FilePatch, error) {
from, to, err := c.Files()
if err != nil {
return nil, err
}
fromContent, fIsBinary, err := fileContent(from)
if err != nil {
return nil, err
}
toContent, tIsBinary, err := fileContent(to)
if err != nil {
return nil, err
}
if fIsBinary || tIsBinary {
return &textFilePatch{from: c.From, to: c.To}, nil
}
diffs := diff.Do(fromContent, toContent)
var chunks []fdiff.Chunk
for _, d := range diffs {
select {
case <-ctx.Done():
return nil, ErrCanceled
default:
}
var op fdiff.Operation
switch d.Type {
case dmp.DiffEqual:
op = fdiff.Equal
case dmp.DiffDelete:
op = fdiff.Delete
case dmp.DiffInsert:
op = fdiff.Add
}
chunks = append(chunks, &textChunk{d.Text, op})
}
return &textFilePatch{
chunks: chunks,
from: c.From,
to: c.To,
}, nil
}
func fileContent(f *File) (content string, isBinary bool, err error) {
if f == nil {
return
}
isBinary, err = f.IsBinary()
if err != nil || isBinary {
return
}
content, err = f.Contents()
return
}
// Patch is an implementation of fdiff.Patch interface
type Patch struct {
message string
filePatches []fdiff.FilePatch
}
func (p *Patch) FilePatches() []fdiff.FilePatch {
return p.filePatches
}
func (p *Patch) Message() string {
return p.message
}
func (p *Patch) Encode(w io.Writer) error {
ue := fdiff.NewUnifiedEncoder(w, fdiff.DefaultContextLines)
return ue.Encode(p)
}
func (p *Patch) Stats() FileStats {
return getFileStatsFromFilePatches(p.FilePatches())
}
func (p *Patch) String() string {
buf := bytes.NewBuffer(nil)
err := p.Encode(buf)
if err != nil {
return fmt.Sprintf("malformed patch: %s", err.Error())
}
return buf.String()
}
// changeEntryWrapper is an implementation of fdiff.File interface
type changeEntryWrapper struct {
ce ChangeEntry
}
func (f *changeEntryWrapper) Hash() plumbing.Hash {
if !f.ce.TreeEntry.Mode.IsFile() {
return plumbing.ZeroHash
}
return f.ce.TreeEntry.Hash
}
func (f *changeEntryWrapper) Mode() filemode.FileMode {
return f.ce.TreeEntry.Mode
}
func (f *changeEntryWrapper) Path() string {
if !f.ce.TreeEntry.Mode.IsFile() {
return ""
}
return f.ce.Name
}
func (f *changeEntryWrapper) Empty() bool {
return !f.ce.TreeEntry.Mode.IsFile()
}
// textFilePatch is an implementation of fdiff.FilePatch interface
type textFilePatch struct {
chunks []fdiff.Chunk
from, to ChangeEntry
}
func (tf *textFilePatch) Files() (from fdiff.File, to fdiff.File) {
f := &changeEntryWrapper{tf.from}
t := &changeEntryWrapper{tf.to}
if !f.Empty() {
from = f
}
if !t.Empty() {
to = t
}
return
}
func (tf *textFilePatch) IsBinary() bool {
return len(tf.chunks) == 0
}
func (tf *textFilePatch) Chunks() []fdiff.Chunk {
return tf.chunks
}
// textChunk is an implementation of fdiff.Chunk interface
type textChunk struct {
content string
op fdiff.Operation
}
func (t *textChunk) Content() string {
return t.content
}
func (t *textChunk) Type() fdiff.Operation {
return t.op
}
// FileStat stores the status of changes in content of a file.
type FileStat struct {
Name string
Addition int
Deletion int
}
func (fs FileStat) String() string {
return printStat([]FileStat{fs})
}
// FileStats is a collection of FileStat.
type FileStats []FileStat
func (fileStats FileStats) String() string {
return printStat(fileStats)
}
// printStat prints the stats of changes in content of files.
// Original implementation: https://github.com/git/git/blob/1a87c842ece327d03d08096395969aca5e0a6996/diff.c#L2615
// Parts of the output:
// <pad><filename><pad>|<pad><changeNumber><pad><+++/---><newline>
// example: " main.go | 10 +++++++--- "
func printStat(fileStats []FileStat) string {
maxGraphWidth := uint(53)
maxNameLen := 0
maxChangeLen := 0
scaleLinear := func(it, width, max uint) uint {
if it == 0 || max == 0 {
return 0
}
return 1 + (it * (width - 1) / max)
}
for _, fs := range fileStats {
if len(fs.Name) > maxNameLen {
maxNameLen = len(fs.Name)
}
changes := strconv.Itoa(fs.Addition + fs.Deletion)
if len(changes) > maxChangeLen {
maxChangeLen = len(changes)
}
}
result := ""
for _, fs := range fileStats {
add := uint(fs.Addition)
del := uint(fs.Deletion)
np := maxNameLen - len(fs.Name)
cp := maxChangeLen - len(strconv.Itoa(fs.Addition+fs.Deletion))
total := add + del
if total > maxGraphWidth {
add = scaleLinear(add, maxGraphWidth, total)
del = scaleLinear(del, maxGraphWidth, total)
}
adds := strings.Repeat("+", int(add))
dels := strings.Repeat("-", int(del))
namePad := strings.Repeat(" ", np)
changePad := strings.Repeat(" ", cp)
result += fmt.Sprintf(" %s%s | %s%d %s%s\n", fs.Name, namePad, changePad, total, adds, dels)
}
return result
}
func getFileStatsFromFilePatches(filePatches []fdiff.FilePatch) FileStats {
var fileStats FileStats
for _, fp := range filePatches {
// ignore empty patches (binary files, submodule refs updates)
if len(fp.Chunks()) == 0 {
continue
}
cs := FileStat{}
from, to := fp.Files()
if from == nil {
// New File is created.
cs.Name = to.Path()
} else if to == nil {
// File is deleted.
cs.Name = from.Path()
} else if from.Path() != to.Path() {
// File is renamed.
cs.Name = fmt.Sprintf("%s => %s", from.Path(), to.Path())
} else {
cs.Name = from.Path()
}
for _, chunk := range fp.Chunks() {
s := chunk.Content()
if len(s) == 0 {
continue
}
switch chunk.Type() {
case fdiff.Add:
cs.Addition += strings.Count(s, "\n")
if s[len(s)-1] != '\n' {
cs.Addition++
}
case fdiff.Delete:
cs.Deletion += strings.Count(s, "\n")
if s[len(s)-1] != '\n' {
cs.Deletion++
}
}
}
fileStats = append(fileStats, cs)
}
return fileStats
}
