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gitea/services/gitdiff/gitdiff.go

1545 lines
46 KiB

// Copyright 2014 The Gogs Authors. All rights reserved.
// Copyright 2019 The Gitea Authors. All rights reserved.
// Use of this source code is governed by a MIT-style
// license that can be found in the LICENSE file.
package gitdiff
import (
"bufio"
"bytes"
"context"
"fmt"
"html"
"html/template"
"io"
"net/url"
"os"
"os/exec"
"regexp"
"sort"
"strings"
"time"
"code.gitea.io/gitea/models"
"code.gitea.io/gitea/models/db"
user_model "code.gitea.io/gitea/models/user"
"code.gitea.io/gitea/modules/analyze"
"code.gitea.io/gitea/modules/charset"
"code.gitea.io/gitea/modules/git"
"code.gitea.io/gitea/modules/highlight"
"code.gitea.io/gitea/modules/lfs"
"code.gitea.io/gitea/modules/log"
"code.gitea.io/gitea/modules/process"
"code.gitea.io/gitea/modules/setting"
"github.com/sergi/go-diff/diffmatchpatch"
stdcharset "golang.org/x/net/html/charset"
"golang.org/x/text/encoding"
"golang.org/x/text/transform"
)
// DiffLineType represents the type of a DiffLine.
type DiffLineType uint8
// DiffLineType possible values.
const (
DiffLinePlain DiffLineType = iota + 1
DiffLineAdd
DiffLineDel
DiffLineSection
)
// DiffFileType represents the type of a DiffFile.
type DiffFileType uint8
// DiffFileType possible values.
const (
DiffFileAdd DiffFileType = iota + 1
DiffFileChange
DiffFileDel
DiffFileRename
DiffFileCopy
)
// DiffLineExpandDirection represents the DiffLineSection expand direction
type DiffLineExpandDirection uint8
// DiffLineExpandDirection possible values.
const (
DiffLineExpandNone DiffLineExpandDirection = iota + 1
DiffLineExpandSingle
DiffLineExpandUpDown
DiffLineExpandUp
DiffLineExpandDown
)
// DiffLine represents a line difference in a DiffSection.
type DiffLine struct {
LeftIdx int
RightIdx int
Match int
Type DiffLineType
Content string
Comments []*models.Comment
SectionInfo *DiffLineSectionInfo
}
// DiffLineSectionInfo represents diff line section meta data
type DiffLineSectionInfo struct {
Path string
LastLeftIdx int
LastRightIdx int
LeftIdx int
RightIdx int
LeftHunkSize int
RightHunkSize int
}
// BlobExcerptChunkSize represent max lines of excerpt
const BlobExcerptChunkSize = 20
// GetType returns the type of a DiffLine.
func (d *DiffLine) GetType() int {
return int(d.Type)
}
// CanComment returns whether or not a line can get commented
func (d *DiffLine) CanComment() bool {
return len(d.Comments) == 0 && d.Type != DiffLineSection
}
// GetCommentSide returns the comment side of the first comment, if not set returns empty string
func (d *DiffLine) GetCommentSide() string {
if len(d.Comments) == 0 {
return ""
}
return d.Comments[0].DiffSide()
}
// GetLineTypeMarker returns the line type marker
func (d *DiffLine) GetLineTypeMarker() string {
if strings.IndexByte(" +-", d.Content[0]) > -1 {
return d.Content[0:1]
}
return ""
}
// GetBlobExcerptQuery builds query string to get blob excerpt
func (d *DiffLine) GetBlobExcerptQuery() string {
query := fmt.Sprintf(
"last_left=%d&last_right=%d&"+
"left=%d&right=%d&"+
"left_hunk_size=%d&right_hunk_size=%d&"+
"path=%s",
d.SectionInfo.LastLeftIdx, d.SectionInfo.LastRightIdx,
d.SectionInfo.LeftIdx, d.SectionInfo.RightIdx,
d.SectionInfo.LeftHunkSize, d.SectionInfo.RightHunkSize,
url.QueryEscape(d.SectionInfo.Path))
return query
}
// GetExpandDirection gets DiffLineExpandDirection
func (d *DiffLine) GetExpandDirection() DiffLineExpandDirection {
if d.Type != DiffLineSection || d.SectionInfo == nil || d.SectionInfo.RightIdx-d.SectionInfo.LastRightIdx <= 1 {
return DiffLineExpandNone
}
if d.SectionInfo.LastLeftIdx <= 0 && d.SectionInfo.LastRightIdx <= 0 {
return DiffLineExpandUp
} else if d.SectionInfo.RightIdx-d.SectionInfo.LastRightIdx > BlobExcerptChunkSize && d.SectionInfo.RightHunkSize > 0 {
return DiffLineExpandUpDown
} else if d.SectionInfo.LeftHunkSize <= 0 && d.SectionInfo.RightHunkSize <= 0 {
return DiffLineExpandDown
}
return DiffLineExpandSingle
}
func getDiffLineSectionInfo(treePath, line string, lastLeftIdx, lastRightIdx int) *DiffLineSectionInfo {
leftLine, leftHunk, rightLine, righHunk := git.ParseDiffHunkString(line)
return &DiffLineSectionInfo{
Path: treePath,
LastLeftIdx: lastLeftIdx,
LastRightIdx: lastRightIdx,
LeftIdx: leftLine,
RightIdx: rightLine,
LeftHunkSize: leftHunk,
RightHunkSize: righHunk,
}
}
// escape a line's content or return <br> needed for copy/paste purposes
func getLineContent(content string) DiffInline {
if len(content) > 0 {
return DiffInlineWithUnicodeEscape(template.HTML(html.EscapeString(content)))
}
return DiffInline{Content: "<br>"}
}
// DiffSection represents a section of a DiffFile.
type DiffSection struct {
file *DiffFile
FileName string
Name string
Lines []*DiffLine
}
var (
addedCodePrefix = []byte(`<span class="added-code">`)
removedCodePrefix = []byte(`<span class="removed-code">`)
codeTagSuffix = []byte(`</span>`)
)
var unfinishedtagRegex = regexp.MustCompile(`<[^>]*$`)
var trailingSpanRegex = regexp.MustCompile(`<span\s*[[:alpha:]="]*?[>]?$`)
var entityRegex = regexp.MustCompile(`&[#]*?[0-9[:alpha:]]*$`)
// shouldWriteInline represents combinations where we manually write inline changes
func shouldWriteInline(diff diffmatchpatch.Diff, lineType DiffLineType) bool {
if true &&
diff.Type == diffmatchpatch.DiffEqual ||
diff.Type == diffmatchpatch.DiffInsert && lineType == DiffLineAdd ||
diff.Type == diffmatchpatch.DiffDelete && lineType == DiffLineDel {
return true
}
return false
}
func fixupBrokenSpans(diffs []diffmatchpatch.Diff) []diffmatchpatch.Diff {
// Create a new array to store our fixed up blocks
fixedup := make([]diffmatchpatch.Diff, 0, len(diffs))
// semantically label some numbers
const insert, delete, equal = 0, 1, 2
// record the positions of the last type of each block in the fixedup blocks
last := []int{-1, -1, -1}
operation := []diffmatchpatch.Operation{diffmatchpatch.DiffInsert, diffmatchpatch.DiffDelete, diffmatchpatch.DiffEqual}
// create a writer for insert and deletes
toWrite := []strings.Builder{
{},
{},
}
// make some flags for insert and delete
unfinishedTag := []bool{false, false}
unfinishedEnt := []bool{false, false}
// store stores the provided text in the writer for the typ
store := func(text string, typ int) {
(&(toWrite[typ])).WriteString(text)
}
// hasStored returns true if there is stored content
hasStored := func(typ int) bool {
return (&toWrite[typ]).Len() > 0
}
// stored will return that content
stored := func(typ int) string {
return (&toWrite[typ]).String()
}
// empty will empty the stored content
empty := func(typ int) {
(&toWrite[typ]).Reset()
}
// pop will remove the stored content appending to a diff block for that typ
pop := func(typ int, fixedup []diffmatchpatch.Diff) []diffmatchpatch.Diff {
if hasStored(typ) {
if last[typ] > last[equal] {
fixedup[last[typ]].Text += stored(typ)
} else {
fixedup = append(fixedup, diffmatchpatch.Diff{
Type: operation[typ],
Text: stored(typ),
})
}
empty(typ)
}
return fixedup
}
// Now we walk the provided diffs and check the type of each block in turn
for _, diff := range diffs {
typ := delete // flag for handling insert or delete typs
switch diff.Type {
case diffmatchpatch.DiffEqual:
// First check if there is anything stored
if hasStored(insert) || hasStored(delete) {
// There are two reasons for storing content:
// 1. Unfinished Entity <- Could be more efficient here by not doing this if we're looking for a tag
if unfinishedEnt[insert] || unfinishedEnt[delete] {
// we look for a ';' to finish an entity
idx := strings.IndexRune(diff.Text, ';')
if idx >= 0 {
// if we find a ';' store the preceding content to both insert and delete
store(diff.Text[:idx+1], insert)
store(diff.Text[:idx+1], delete)
// and remove it from this block
diff.Text = diff.Text[idx+1:]
// reset the ent flags
unfinishedEnt[insert] = false
unfinishedEnt[delete] = false
} else {
// otherwise store it all on insert and delete
store(diff.Text, insert)
store(diff.Text, delete)
// and empty this block
diff.Text = ""
}
}
// 2. Unfinished Tag
if unfinishedTag[insert] || unfinishedTag[delete] {
// we look for a '>' to finish a tag
idx := strings.IndexRune(diff.Text, '>')
if idx >= 0 {
store(diff.Text[:idx+1], insert)
store(diff.Text[:idx+1], delete)
diff.Text = diff.Text[idx+1:]
unfinishedTag[insert] = false
unfinishedTag[delete] = false
} else {
store(diff.Text, insert)
store(diff.Text, delete)
diff.Text = ""
}
}
// If we've completed the required tag/entities
if !(unfinishedTag[insert] || unfinishedTag[delete] || unfinishedEnt[insert] || unfinishedEnt[delete]) {
// pop off the stack
fixedup = pop(insert, fixedup)
fixedup = pop(delete, fixedup)
}
// If that has left this diff block empty then shortcut
if len(diff.Text) == 0 {
continue
}
}
// check if this block ends in an unfinished tag?
idx := unfinishedtagRegex.FindStringIndex(diff.Text)
if idx != nil {
unfinishedTag[insert] = true
unfinishedTag[delete] = true
} else {
// otherwise does it end in an unfinished entity?
idx = entityRegex.FindStringIndex(diff.Text)
if idx != nil {
unfinishedEnt[insert] = true
unfinishedEnt[delete] = true
}
}
// If there is an unfinished component
if idx != nil {
// Store the fragment
store(diff.Text[idx[0]:], insert)
store(diff.Text[idx[0]:], delete)
// and remove it from this block
diff.Text = diff.Text[:idx[0]]
}
// If that hasn't left the block empty
if len(diff.Text) > 0 {
// store the position of the last equal block and store it in our diffs
last[equal] = len(fixedup)
fixedup = append(fixedup, diff)
}
continue
case diffmatchpatch.DiffInsert:
typ = insert
fallthrough
case diffmatchpatch.DiffDelete:
// First check if there is anything stored for this type
if hasStored(typ) {
// if there is prepend it to this block, empty the storage and reset our flags
diff.Text = stored(typ) + diff.Text
empty(typ)
unfinishedEnt[typ] = false
unfinishedTag[typ] = false
}
// check if this block ends in an unfinished tag
idx := unfinishedtagRegex.FindStringIndex(diff.Text)
if idx != nil {
unfinishedTag[typ] = true
} else {
// otherwise does it end in an unfinished entity
idx = entityRegex.FindStringIndex(diff.Text)
if idx != nil {
unfinishedEnt[typ] = true
}
}
// If there is an unfinished component
if idx != nil {
// Store the fragment
store(diff.Text[idx[0]:], typ)
// and remove it from this block
diff.Text = diff.Text[:idx[0]]
}
// If that hasn't left the block empty
if len(diff.Text) > 0 {
// if the last block of this type was after the last equal block
if last[typ] > last[equal] {
// store this blocks content on that block
fixedup[last[typ]].Text += diff.Text
} else {
// otherwise store the position of the last block of this type and store the block
last[typ] = len(fixedup)
fixedup = append(fixedup, diff)
}
}
continue
}
}
// pop off any remaining stored content
fixedup = pop(insert, fixedup)
fixedup = pop(delete, fixedup)
return fixedup
}
func diffToHTML(fileName string, diffs []diffmatchpatch.Diff, lineType DiffLineType) DiffInline {
buf := bytes.NewBuffer(nil)
match := ""
diffs = fixupBrokenSpans(diffs)
for _, diff := range diffs {
if shouldWriteInline(diff, lineType) {
if len(match) > 0 {
diff.Text = match + diff.Text
match = ""
}
// Chroma HTML syntax highlighting is done before diffing individual lines in order to maintain consistency.
// Since inline changes might split in the middle of a chroma span tag or HTML entity, make we manually put it back together
// before writing so we don't try insert added/removed code spans in the middle of one of those
// and create broken HTML. This is done by moving incomplete HTML forward until it no longer matches our pattern of
// a line ending with an incomplete HTML entity or partial/opening <span>.
// EX:
// diffs[{Type: dmp.DiffDelete, Text: "language</span><span "},
// {Type: dmp.DiffEqual, Text: "c"},
// {Type: dmp.DiffDelete, Text: "lass="p">}]
// After first iteration
// diffs[{Type: dmp.DiffDelete, Text: "language</span>"}, //write out
// {Type: dmp.DiffEqual, Text: "<span c"},
// {Type: dmp.DiffDelete, Text: "lass="p">,</span>}]
// After second iteration
// {Type: dmp.DiffEqual, Text: ""}, // write out
// {Type: dmp.DiffDelete, Text: "<span class="p">,</span>}]
// Final
// {Type: dmp.DiffDelete, Text: "<span class="p">,</span>}]
// end up writing <span class="removed-code"><span class="p">,</span></span>
// Instead of <span class="removed-code">lass="p",</span></span>
m := trailingSpanRegex.FindStringSubmatchIndex(diff.Text)
if m != nil {
match = diff.Text[m[0]:m[1]]
diff.Text = strings.TrimSuffix(diff.Text, match)
}
m = entityRegex.FindStringSubmatchIndex(diff.Text)
if m != nil {
match = diff.Text[m[0]:m[1]]
diff.Text = strings.TrimSuffix(diff.Text, match)
}
// Print an existing closing span first before opening added/remove-code span so it doesn't unintentionally close it
if strings.HasPrefix(diff.Text, "</span>") {
buf.WriteString("</span>")
diff.Text = strings.TrimPrefix(diff.Text, "</span>")
}
// If we weren't able to fix it then this should avoid broken HTML by not inserting more spans below
// The previous/next diff section will contain the rest of the tag that is missing here
if strings.Count(diff.Text, "<") != strings.Count(diff.Text, ">") {
buf.WriteString(diff.Text)
continue
}
}
switch {
case diff.Type == diffmatchpatch.DiffEqual:
buf.WriteString(diff.Text)
case diff.Type == diffmatchpatch.DiffInsert && lineType == DiffLineAdd:
buf.Write(addedCodePrefix)
buf.WriteString(diff.Text)
buf.Write(codeTagSuffix)
case diff.Type == diffmatchpatch.DiffDelete && lineType == DiffLineDel:
buf.Write(removedCodePrefix)
buf.WriteString(diff.Text)
buf.Write(codeTagSuffix)
}
}
return DiffInlineWithUnicodeEscape(template.HTML(buf.String()))
}
// GetLine gets a specific line by type (add or del) and file line number
func (diffSection *DiffSection) GetLine(lineType DiffLineType, idx int) *DiffLine {
var (
difference = 0
addCount = 0
delCount = 0
matchDiffLine *DiffLine
)
LOOP:
for _, diffLine := range diffSection.Lines {
switch diffLine.Type {
case DiffLineAdd:
addCount++
case DiffLineDel:
delCount++
default:
if matchDiffLine != nil {
break LOOP
}
difference = diffLine.RightIdx - diffLine.LeftIdx
addCount = 0
delCount = 0
}
switch lineType {
case DiffLineDel:
if diffLine.RightIdx == 0 && diffLine.LeftIdx == idx-difference {
matchDiffLine = diffLine
}
case DiffLineAdd:
if diffLine.LeftIdx == 0 && diffLine.RightIdx == idx+difference {
matchDiffLine = diffLine
}
}
}
if addCount == delCount {
return matchDiffLine
}
return nil
}
var diffMatchPatch = diffmatchpatch.New()
func init() {
diffMatchPatch.DiffEditCost = 100
}
// DiffInline is a struct that has a content and escape status
type DiffInline struct {
EscapeStatus charset.EscapeStatus
Content template.HTML
}
// DiffInlineWithUnicodeEscape makes a DiffInline with hidden unicode characters escaped
func DiffInlineWithUnicodeEscape(s template.HTML) DiffInline {
status, content := charset.EscapeControlString(string(s))
return DiffInline{EscapeStatus: status, Content: template.HTML(content)}
}
// DiffInlineWithHighlightCode makes a DiffInline with code highlight and hidden unicode characters escaped
func DiffInlineWithHighlightCode(fileName, language, code string) DiffInline {
status, content := charset.EscapeControlString(highlight.Code(fileName, language, code))
return DiffInline{EscapeStatus: status, Content: template.HTML(content)}
}
// GetComputedInlineDiffFor computes inline diff for the given line.
func (diffSection *DiffSection) GetComputedInlineDiffFor(diffLine *DiffLine) DiffInline {
if setting.Git.DisableDiffHighlight {
return getLineContent(diffLine.Content[1:])
}
var (
compareDiffLine *DiffLine
diff1 string
diff2 string
)
language := ""
if diffSection.file != nil {
language = diffSection.file.Language
}
// try to find equivalent diff line. ignore, otherwise
switch diffLine.Type {
case DiffLineSection:
return getLineContent(diffLine.Content[1:])
case DiffLineAdd:
compareDiffLine = diffSection.GetLine(DiffLineDel, diffLine.RightIdx)
if compareDiffLine == nil {
return DiffInlineWithHighlightCode(diffSection.FileName, language, diffLine.Content[1:])
}
diff1 = compareDiffLine.Content
diff2 = diffLine.Content
case DiffLineDel:
compareDiffLine = diffSection.GetLine(DiffLineAdd, diffLine.LeftIdx)
if compareDiffLine == nil {
return DiffInlineWithHighlightCode(diffSection.FileName, language, diffLine.Content[1:])
}
diff1 = diffLine.Content
diff2 = compareDiffLine.Content
default:
if strings.IndexByte(" +-", diffLine.Content[0]) > -1 {
return DiffInlineWithHighlightCode(diffSection.FileName, language, diffLine.Content[1:])
}
return DiffInlineWithHighlightCode(diffSection.FileName, language, diffLine.Content)
}
diffRecord := diffMatchPatch.DiffMain(highlight.Code(diffSection.FileName, language, diff1[1:]), highlight.Code(diffSection.FileName, language, diff2[1:]), true)
diffRecord = diffMatchPatch.DiffCleanupEfficiency(diffRecord)
return diffToHTML(diffSection.FileName, diffRecord, diffLine.Type)
}
// DiffFile represents a file diff.
type DiffFile struct {
Name string
OldName string
Index int
Addition, Deletion int
Type DiffFileType
IsCreated bool
IsDeleted bool
IsBin bool
IsLFSFile bool
IsRenamed bool
IsAmbiguous bool
IsSubmodule bool
Sections []*DiffSection
IsIncomplete bool
IsIncompleteLineTooLong bool
IsProtected bool
IsGenerated bool
IsVendored bool
Language string
}
// GetType returns type of diff file.
func (diffFile *DiffFile) GetType() int {
return int(diffFile.Type)
}
// GetTailSection creates a fake DiffLineSection if the last section is not the end of the file
func (diffFile *DiffFile) GetTailSection(gitRepo *git.Repository, leftCommitID, rightCommitID string) *DiffSection {
if len(diffFile.Sections) == 0 || diffFile.Type != DiffFileChange || diffFile.IsBin || diffFile.IsLFSFile {
return nil
}
leftCommit, err := gitRepo.GetCommit(leftCommitID)
if err != nil {
return nil
}
rightCommit, err := gitRepo.GetCommit(rightCommitID)
if err != nil {
return nil
}
lastSection := diffFile.Sections[len(diffFile.Sections)-1]
lastLine := lastSection.Lines[len(lastSection.Lines)-1]
leftLineCount := getCommitFileLineCount(leftCommit, diffFile.Name)
rightLineCount := getCommitFileLineCount(rightCommit, diffFile.Name)
if leftLineCount <= lastLine.LeftIdx || rightLineCount <= lastLine.RightIdx {
return nil
}
tailDiffLine := &DiffLine{
Type: DiffLineSection,
Content: " ",
SectionInfo: &DiffLineSectionInfo{
Path: diffFile.Name,
LastLeftIdx: lastLine.LeftIdx,
LastRightIdx: lastLine.RightIdx,
LeftIdx: leftLineCount,
RightIdx: rightLineCount,
}}
tailSection := &DiffSection{FileName: diffFile.Name, Lines: []*DiffLine{tailDiffLine}}
return tailSection
}
func getCommitFileLineCount(commit *git.Commit, filePath string) int {
blob, err := commit.GetBlobByPath(filePath)
if err != nil {
return 0
}
lineCount, err := blob.GetBlobLineCount()
if err != nil {
return 0
}
return lineCount
}
// Diff represents a difference between two git trees.
type Diff struct {
Start, End string
NumFiles, TotalAddition, TotalDeletion int
Files []*DiffFile
IsIncomplete bool
}
// LoadComments loads comments into each line
func (diff *Diff) LoadComments(ctx context.Context, issue *models.Issue, currentUser *user_model.User) error {
allComments, err := models.FetchCodeComments(ctx, issue, currentUser)
if err != nil {
return err
}
for _, file := range diff.Files {
if lineCommits, ok := allComments[file.Name]; ok {
for _, section := range file.Sections {
for _, line := range section.Lines {
if comments, ok := lineCommits[int64(line.LeftIdx*-1)]; ok {
line.Comments = append(line.Comments, comments...)
}
if comments, ok := lineCommits[int64(line.RightIdx)]; ok {
line.Comments = append(line.Comments, comments...)
}
sort.SliceStable(line.Comments, func(i, j int) bool {
return line.Comments[i].CreatedUnix < line.Comments[j].CreatedUnix
})
}
}
}
}
return nil
}
const cmdDiffHead = "diff --git "
// ParsePatch builds a Diff object from a io.Reader and some parameters.
func ParsePatch(maxLines, maxLineCharacters, maxFiles int, reader io.Reader, skipToFile string) (*Diff, error) {
log.Debug("ParsePatch(%d, %d, %d, ..., %s)", maxLines, maxLineCharacters, maxFiles, skipToFile)
var curFile *DiffFile
skipping := skipToFile != ""
diff := &Diff{Files: make([]*DiffFile, 0)}
sb := strings.Builder{}
// OK let's set a reasonable buffer size.
// This should be let's say at least the size of maxLineCharacters or 4096 whichever is larger.
readerSize := maxLineCharacters
if readerSize < 4096 {
readerSize = 4096
}
input := bufio.NewReaderSize(reader, readerSize)
line, err := input.ReadString('\n')
if err != nil {
if err == io.EOF {
return diff, nil
}
return diff, err
}
parsingLoop:
for {
// 1. A patch file always begins with `diff --git ` + `a/path b/path` (possibly quoted)
// if it does not we have bad input!
if !strings.HasPrefix(line, cmdDiffHead) {
return diff, fmt.Errorf("invalid first file line: %s", line)
}
if maxFiles > -1 && len(diff.Files) >= maxFiles {
lastFile := createDiffFile(diff, line)
diff.End = lastFile.Name
diff.IsIncomplete = true
_, err := io.Copy(io.Discard, reader)
if err != nil {
// By the definition of io.Copy this never returns io.EOF
return diff, fmt.Errorf("error during io.Copy: %w", err)
}
break parsingLoop
}
curFile = createDiffFile(diff, line)
if skipping {
if curFile.Name != skipToFile {
line, err = skipToNextDiffHead(input)
if err != nil {
if err == io.EOF {
return diff, nil
}
return diff, err
}
continue
}
skipping = false
}
diff.Files = append(diff.Files, curFile)
// 2. It is followed by one or more extended header lines:
//
// old mode <mode>
// new mode <mode>
// deleted file mode <mode>
// new file mode <mode>
// copy from <path>
// copy to <path>
// rename from <path>
// rename to <path>
// similarity index <number>
// dissimilarity index <number>
// index <hash>..<hash> <mode>
//
// * <mode> 6-digit octal numbers including the file type and file permission bits.
// * <path> does not include the a/ and b/ prefixes
// * <number> percentage of unchanged lines for similarity, percentage of changed
// lines dissimilarity as integer rounded down with terminal %. 100% => equal files.
// * The index line includes the blob object names before and after the change.
// The <mode> is included if the file mode does not change; otherwise, separate
// lines indicate the old and the new mode.
// 3. Following this header the "standard unified" diff format header may be encountered: (but not for every case...)
//
// --- a/<path>
// +++ b/<path>
//
// With multiple hunks
//
// @@ <hunk descriptor> @@
// +added line
// -removed line
// unchanged line
//
// 4. Binary files get:
//
// Binary files a/<path> and b/<path> differ
//
// but one of a/<path> and b/<path> could be /dev/null.
curFileLoop:
for {
line, err = input.ReadString('\n')
if err != nil {
if err != io.EOF {
return diff, err
}
break parsingLoop
}
switch {
case strings.HasPrefix(line, cmdDiffHead):
break curFileLoop
case strings.HasPrefix(line, "old mode ") ||
strings.HasPrefix(line, "new mode "):
if strings.HasSuffix(line, " 160000\n") {
curFile.IsSubmodule = true
}
case strings.HasPrefix(line, "rename from "):
curFile.IsRenamed = true
curFile.Type = DiffFileRename
if curFile.IsAmbiguous {
curFile.OldName = line[len("rename from ") : len(line)-1]
}
case strings.HasPrefix(line, "rename to "):
curFile.IsRenamed = true
curFile.Type = DiffFileRename
if curFile.IsAmbiguous {
curFile.Name = line[len("rename to ") : len(line)-1]
curFile.IsAmbiguous = false
}
case strings.HasPrefix(line, "copy from "):
curFile.IsRenamed = true
curFile.Type = DiffFileCopy
if curFile.IsAmbiguous {
curFile.OldName = line[len("copy from ") : len(line)-1]
}
case strings.HasPrefix(line, "copy to "):
curFile.IsRenamed = true
curFile.Type = DiffFileCopy
if curFile.IsAmbiguous {
curFile.Name = line[len("copy to ") : len(line)-1]
curFile.IsAmbiguous = false
}
case strings.HasPrefix(line, "new file"):
curFile.Type = DiffFileAdd
curFile.IsCreated = true
if strings.HasSuffix(line, " 160000\n") {
curFile.IsSubmodule = true
}
case strings.HasPrefix(line, "deleted"):
curFile.Type = DiffFileDel
curFile.IsDeleted = true
if strings.HasSuffix(line, " 160000\n") {
curFile.IsSubmodule = true
}
case strings.HasPrefix(line, "index"):
if strings.HasSuffix(line, " 160000\n") {
curFile.IsSubmodule = true
}
case strings.HasPrefix(line, "similarity index 100%"):
curFile.Type = DiffFileRename
case strings.HasPrefix(line, "Binary"):
curFile.IsBin = true
case strings.HasPrefix(line, "--- "):
// Handle ambiguous filenames
if curFile.IsAmbiguous {
// The shortest string that can end up here is:
// "--- a\t\n" without the quotes.
// This line has a len() of 7 but doesn't contain a oldName.
// So the amount that the line need is at least 8 or more.
// The code will otherwise panic for a out-of-bounds.
if len(line) > 7 && line[4] == 'a' {
curFile.OldName = line[6 : len(line)-1]
if line[len(line)-2] == '\t' {
curFile.OldName = curFile.OldName[:len(curFile.OldName)-1]
}
} else {
curFile.OldName = ""
}
}
// Otherwise do nothing with this line
case strings.HasPrefix(line, "+++ "):
// Handle ambiguous filenames
if curFile.IsAmbiguous {
if len(line) > 6 && line[4] == 'b' {
curFile.Name = line[6 : len(line)-1]
if line[len(line)-2] == '\t' {
curFile.Name = curFile.Name[:len(curFile.Name)-1]
}
if curFile.OldName == "" {
curFile.OldName = curFile.Name
}
} else {
curFile.Name = curFile.OldName
}
curFile.IsAmbiguous = false
}
// Otherwise do nothing with this line, but now switch to parsing hunks
lineBytes, isFragment, err := parseHunks(curFile, maxLines, maxLineCharacters, input)
diff.TotalAddition += curFile.Addition
diff.TotalDeletion += curFile.Deletion
if err != nil {
if err != io.EOF {
return diff, err
}
break parsingLoop
}
sb.Reset()
_, _ = sb.Write(lineBytes)
for isFragment {
lineBytes, isFragment, err = input.ReadLine()
if err != nil {
// Now by the definition of ReadLine this cannot be io.EOF
return diff, fmt.Errorf("unable to ReadLine: %w", err)
}
_, _ = sb.Write(lineBytes)
}
line = sb.String()
sb.Reset()
break curFileLoop
}
}
}
// TODO: There are numerous issues with this:
// - we might want to consider detecting encoding while parsing but...
// - we're likely to fail to get the correct encoding here anyway as we won't have enough information
var diffLineTypeBuffers = make(map[DiffLineType]*bytes.Buffer, 3)
var diffLineTypeDecoders = make(map[DiffLineType]*encoding.Decoder, 3)
diffLineTypeBuffers[DiffLinePlain] = new(bytes.Buffer)
diffLineTypeBuffers[DiffLineAdd] = new(bytes.Buffer)
diffLineTypeBuffers[DiffLineDel] = new(bytes.Buffer)
for _, f := range diff.Files {
for _, buffer := range diffLineTypeBuffers {
buffer.Reset()
}
for _, sec := range f.Sections {
for _, l := range sec.Lines {
if l.Type == DiffLineSection {
continue
}
diffLineTypeBuffers[l.Type].WriteString(l.Content[1:])
diffLineTypeBuffers[l.Type].WriteString("\n")
}
}
for lineType, buffer := range diffLineTypeBuffers {
diffLineTypeDecoders[lineType] = nil
if buffer.Len() == 0 {
continue
}
charsetLabel, err := charset.DetectEncoding(buffer.Bytes())
if charsetLabel != "UTF-8" && err == nil {
encoding, _ := stdcharset.Lookup(charsetLabel)
if encoding != nil {
diffLineTypeDecoders[lineType] = encoding.NewDecoder()
}
}
}
for _, sec := range f.Sections {
for _, l := range sec.Lines {
decoder := diffLineTypeDecoders[l.Type]
if decoder != nil {
if c, _, err := transform.String(decoder, l.Content[1:]); err == nil {
l.Content = l.Content[0:1] + c
}
}
}
}
}
diff.NumFiles = len(diff.Files)
return diff, nil
}
func skipToNextDiffHead(input *bufio.Reader) (line string, err error) {
// need to skip until the next cmdDiffHead
isFragment, wasFragment := false, false
var lineBytes []byte
for {
lineBytes, isFragment, err = input.ReadLine()
if err != nil {
return
}
if wasFragment {
wasFragment = isFragment
continue
}
if bytes.HasPrefix(lineBytes, []byte(cmdDiffHead)) {
break
}
wasFragment = isFragment
}
line = string(lineBytes)
if isFragment {
var tail string
tail, err = input.ReadString('\n')
if err != nil {
return
}
line += tail
}
return
}
func parseHunks(curFile *DiffFile, maxLines, maxLineCharacters int, input *bufio.Reader) (lineBytes []byte, isFragment bool, err error) {
sb := strings.Builder{}
var (
curSection *DiffSection
curFileLinesCount int
curFileLFSPrefix bool
)
lastLeftIdx := -1
leftLine, rightLine := 1, 1
for {
for isFragment {
curFile.IsIncomplete = true
curFile.IsIncompleteLineTooLong = true
_, isFragment, err = input.ReadLine()
if err != nil {
// Now by the definition of ReadLine this cannot be io.EOF
err = fmt.Errorf("unable to ReadLine: %w", err)
return
}
}
sb.Reset()
lineBytes, isFragment, err = input.ReadLine()
if err != nil {
if err == io.EOF {
return
}
err = fmt.Errorf("unable to ReadLine: %w", err)
return
}
if lineBytes[0] == 'd' {
// End of hunks
return
}
switch lineBytes[0] {
case '@':
if maxLines > -1 && curFileLinesCount >= maxLines {
curFile.IsIncomplete = true
continue
}
_, _ = sb.Write(lineBytes)
for isFragment {
// This is very odd indeed - we're in a section header and the line is too long
// This really shouldn't happen...
lineBytes, isFragment, err = input.ReadLine()
if err != nil {
// Now by the definition of ReadLine this cannot be io.EOF
err = fmt.Errorf("unable to ReadLine: %w", err)
return
}
_, _ = sb.Write(lineBytes)
}
line := sb.String()
// Create a new section to represent this hunk
curSection = &DiffSection{file: curFile}
lastLeftIdx = -1
curFile.Sections = append(curFile.Sections, curSection)
lineSectionInfo := getDiffLineSectionInfo(curFile.Name, line, leftLine-1, rightLine-1)
diffLine := &DiffLine{
Type: DiffLineSection,
Content: line,
SectionInfo: lineSectionInfo,
}
curSection.Lines = append(curSection.Lines, diffLine)
curSection.FileName = curFile.Name
// update line number.
leftLine = lineSectionInfo.LeftIdx
rightLine = lineSectionInfo.RightIdx
continue
case '\\':
if maxLines > -1 && curFileLinesCount >= maxLines {
curFile.IsIncomplete = true
continue
}
// This is used only to indicate that the current file does not have a terminal newline
if !bytes.Equal(lineBytes, []byte("\\ No newline at end of file")) {
err = fmt.Errorf("unexpected line in hunk: %s", string(lineBytes))
return
}
// Technically this should be the end the file!
// FIXME: we should be putting a marker at the end of the file if there is no terminal new line
continue
case '+':
curFileLinesCount++
curFile.Addition++
if maxLines > -1 && curFileLinesCount >= maxLines {
curFile.IsIncomplete = true
continue
}
diffLine := &DiffLine{Type: DiffLineAdd, RightIdx: rightLine, Match: -1}
rightLine++
if curSection == nil {
// Create a new section to represent this hunk
curSection = &DiffSection{file: curFile}
curFile.Sections = append(curFile.Sections, curSection)
lastLeftIdx = -1
}
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.Deletion++
if maxLines > -1 && curFileLinesCount >= maxLines {
curFile.IsIncomplete = true
continue
}
diffLine := &DiffLine{Type: DiffLineDel, LeftIdx: leftLine, Match: -1}
if leftLine > 0 {
leftLine++
}
if curSection == nil {
// Create a new section to represent this hunk
curSection = &DiffSection{file: curFile}
curFile.Sections = append(curFile.Sections, curSection)
lastLeftIdx = -1
}
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++
if maxLines > -1 && curFileLinesCount >= maxLines {
curFile.IsIncomplete = true
continue
}
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{file: curFile}
curFile.Sections = append(curFile.Sections, curSection)
}
curSection.Lines = append(curSection.Lines, diffLine)
default:
// This is unexpected
err = fmt.Errorf("unexpected line in hunk: %s", string(lineBytes))
return
}
line := string(lineBytes)
if isFragment {
curFile.IsIncomplete = true
curFile.IsIncompleteLineTooLong = true
for isFragment {
lineBytes, isFragment, err = input.ReadLine()
if err != nil {
// Now by the definition of ReadLine this cannot be io.EOF
err = fmt.Errorf("unable to ReadLine: %w", err)
return
}
}
}
if len(line) > maxLineCharacters {
curFile.IsIncomplete = true
curFile.IsIncompleteLineTooLong = true
line = line[:maxLineCharacters]
}
curSection.Lines[len(curSection.Lines)-1].Content = line
// handle LFS
if line[1:] == lfs.MetaFileIdentifier {
curFileLFSPrefix = true
} else if curFileLFSPrefix && strings.HasPrefix(line[1:], lfs.MetaFileOidPrefix) {
oid := strings.TrimPrefix(line[1:], lfs.MetaFileOidPrefix)
if len(oid) == 64 {
m := &models.LFSMetaObject{Pointer: lfs.Pointer{Oid: oid}}
count, err := db.Count(m)
if err == nil && count > 0 {
curFile.IsBin = true
curFile.IsLFSFile = true
curSection.Lines = nil
lastLeftIdx = -1
}
}
}
}
}
func createDiffFile(diff *Diff, line string) *DiffFile {
// The a/ and b/ filenames are the same unless rename/copy is involved.
// Especially, even for a creation or a deletion, /dev/null is not used
// in place of the a/ or b/ filenames.
//
// When rename/copy is involved, file1 and file2 show the name of the
// source file of the rename/copy and the name of the file that rename/copy
// produces, respectively.
//
// Path names are quoted if necessary.
//
// This means that you should always be able to determine the file name even when there
// there is potential ambiguity...
//
// but we can be simpler with our heuristics by just forcing git to prefix things nicely
curFile := &DiffFile{
Index: len(diff.Files) + 1,
Type: DiffFileChange,
Sections: make([]*DiffSection, 0, 10),
}
rd := strings.NewReader(line[len(cmdDiffHead):] + " ")
curFile.Type = DiffFileChange
oldNameAmbiguity := false
newNameAmbiguity := false
curFile.OldName, oldNameAmbiguity = readFileName(rd)
curFile.Name, newNameAmbiguity = readFileName(rd)
if oldNameAmbiguity && newNameAmbiguity {
curFile.IsAmbiguous = true
// OK we should bet that the oldName and the newName are the same if they can be made to be same
// So we need to start again ...
if (len(line)-len(cmdDiffHead)-1)%2 == 0 {
// diff --git a/b b/b b/b b/b b/b b/b
//
midpoint := (len(line) + len(cmdDiffHead) - 1) / 2
new, old := line[len(cmdDiffHead):midpoint], line[midpoint+1:]
if len(new) > 2 && len(old) > 2 && new[2:] == old[2:] {
curFile.OldName = old[2:]
curFile.Name = old[2:]
}
}
}
curFile.IsRenamed = curFile.Name != curFile.OldName
return curFile
}
func readFileName(rd *strings.Reader) (string, bool) {
ambiguity := false
var name string
char, _ := rd.ReadByte()
_ = rd.UnreadByte()
if char == '"' {
fmt.Fscanf(rd, "%q ", &name)
if len(name) == 0 {
log.Error("Reader has no file name: %v", rd)
return "", true
}
if name[0] == '\\' {
name = name[1:]
}
} else {
// This technique is potentially ambiguous it may not be possible to uniquely identify the filenames from the diff line alone
ambiguity = true
fmt.Fscanf(rd, "%s ", &name)
char, _ := rd.ReadByte()
_ = rd.UnreadByte()
for !(char == 0 || char == '"' || char == 'b') {
var suffix string
fmt.Fscanf(rd, "%s ", &suffix)
name += " " + suffix
char, _ = rd.ReadByte()
_ = rd.UnreadByte()
}
}
if len(name) < 2 {
log.Error("Unable to determine name from reader: %v", rd)
return "", true
}
return name[2:], ambiguity
}
// DiffOptions represents the options for a DiffRange
type DiffOptions struct {
BeforeCommitID string
AfterCommitID string
SkipTo string
MaxLines int
MaxLineCharacters int
MaxFiles int
WhitespaceBehavior string
DirectComparison bool
}
// GetDiff builds a Diff between two commits of a repository.
// Passing the empty string as beforeCommitID returns a diff from the parent commit.
// The whitespaceBehavior is either an empty string or a git flag
func GetDiff(gitRepo *git.Repository, opts *DiffOptions, files ...string) (*Diff, error) {
repoPath := gitRepo.Path
commit, err := gitRepo.GetCommit(opts.AfterCommitID)
if err != nil {
return nil, err
}
timeout := time.Duration(setting.Git.Timeout.Default) * time.Second
ctx, _, finished := process.GetManager().AddContextTimeout(gitRepo.Ctx, timeout, fmt.Sprintf("GetDiffRange [repo_path: %s]", repoPath))
defer finished()
argsLength := 6
if len(opts.WhitespaceBehavior) > 0 {
argsLength++
}
if len(opts.SkipTo) > 0 {
argsLength++
}
if len(files) > 0 {
argsLength += len(files) + 1
}
diffArgs := make([]string, 0, argsLength)
if (len(opts.BeforeCommitID) == 0 || opts.BeforeCommitID == git.EmptySHA) && commit.ParentCount() == 0 {
diffArgs = append(diffArgs, "diff", "--src-prefix=\\a/", "--dst-prefix=\\b/", "-M")
if len(opts.WhitespaceBehavior) != 0 {
diffArgs = append(diffArgs, opts.WhitespaceBehavior)
}
// append empty tree ref
diffArgs = append(diffArgs, "4b825dc642cb6eb9a060e54bf8d69288fbee4904")
diffArgs = append(diffArgs, opts.AfterCommitID)
} else {
actualBeforeCommitID := opts.BeforeCommitID
if len(actualBeforeCommitID) == 0 {
parentCommit, _ := commit.Parent(0)
actualBeforeCommitID = parentCommit.ID.String()
}
diffArgs = append(diffArgs, "diff", "--src-prefix=\\a/", "--dst-prefix=\\b/", "-M")
if len(opts.WhitespaceBehavior) != 0 {
diffArgs = append(diffArgs, opts.WhitespaceBehavior)
}
diffArgs = append(diffArgs, actualBeforeCommitID)
diffArgs = append(diffArgs, opts.AfterCommitID)
opts.BeforeCommitID = actualBeforeCommitID
}
// In git 2.31, git diff learned --skip-to which we can use to shortcut skip to file
// so if we are using at least this version of git we don't have to tell ParsePatch to do
// the skipping for us
parsePatchSkipToFile := opts.SkipTo
if opts.SkipTo != "" && git.CheckGitVersionAtLeast("2.31") == nil {
diffArgs = append(diffArgs, "--skip-to="+opts.SkipTo)
parsePatchSkipToFile = ""
}
if len(files) > 0 {
diffArgs = append(diffArgs, "--")
diffArgs = append(diffArgs, files...)
}
cmd := exec.CommandContext(ctx, git.GitExecutable, diffArgs...)
cmd.Dir = repoPath
cmd.Stderr = os.Stderr
stdout, err := cmd.StdoutPipe()
if err != nil {
return nil, fmt.Errorf("error creating StdoutPipe: %w", err)
}
if err = cmd.Start(); err != nil {
return nil, fmt.Errorf("error during Start: %w", err)
}
diff, err := ParsePatch(opts.MaxLines, opts.MaxLineCharacters, opts.MaxFiles, stdout, parsePatchSkipToFile)
if err != nil {
return nil, fmt.Errorf("unable to ParsePatch: %w", err)
}
diff.Start = opts.SkipTo
var checker *git.CheckAttributeReader
if git.CheckGitVersionAtLeast("1.7.8") == nil {
indexFilename, worktree, deleteTemporaryFile, err := gitRepo.ReadTreeToTemporaryIndex(opts.AfterCommitID)
if err == nil {
defer deleteTemporaryFile()
checker = &git.CheckAttributeReader{
Attributes: []string{"linguist-vendored", "linguist-generated", "linguist-language", "gitlab-language"},
Repo: gitRepo,
IndexFile: indexFilename,
WorkTree: worktree,
}
ctx, cancel := context.WithCancel(ctx)
if err := checker.Init(ctx); err != nil {
log.Error("Unable to open checker for %s. Error: %v", opts.AfterCommitID, err)
} else {
go func() {
err := checker.Run()
if err != nil && err != ctx.Err() {
log.Error("Unable to open checker for %s. Error: %v", opts.AfterCommitID, err)
}
cancel()
}()
}
defer func() {
cancel()
}()
}
}
for _, diffFile := range diff.Files {
gotVendor := false
gotGenerated := false
if checker != nil {
attrs, err := checker.CheckPath(diffFile.Name)
if err == nil {
if vendored, has := attrs["linguist-vendored"]; has {
if vendored == "set" || vendored == "true" {
diffFile.IsVendored = true
gotVendor = true
} else {
gotVendor = vendored == "false"
}
}
if generated, has := attrs["linguist-generated"]; has {
if generated == "set" || generated == "true" {
diffFile.IsGenerated = true
gotGenerated = true
} else {
gotGenerated = generated == "false"
}
}
if language, has := attrs["linguist-language"]; has && language != "unspecified" && language != "" {
diffFile.Language = language
} else if language, has := attrs["gitlab-language"]; has && language != "unspecified" && language != "" {
diffFile.Language = language
}
} else {
log.Error("Unexpected error: %v", err)
}
}
if !gotVendor {
diffFile.IsVendored = analyze.IsVendor(diffFile.Name)
}
if !gotGenerated {
diffFile.IsGenerated = analyze.IsGenerated(diffFile.Name)
}
tailSection := diffFile.GetTailSection(gitRepo, opts.BeforeCommitID, opts.AfterCommitID)
if tailSection != nil {
diffFile.Sections = append(diffFile.Sections, tailSection)
}
}
if err = cmd.Wait(); err != nil {
return nil, fmt.Errorf("error during cmd.Wait: %w", err)
}
separator := "..."
if opts.DirectComparison {
separator = ".."
}
shortstatArgs := []string{opts.BeforeCommitID + separator + opts.AfterCommitID}
if len(opts.BeforeCommitID) == 0 || opts.BeforeCommitID == git.EmptySHA {
shortstatArgs = []string{git.EmptyTreeSHA, opts.AfterCommitID}
}
diff.NumFiles, diff.TotalAddition, diff.TotalDeletion, err = git.GetDiffShortStat(ctx, repoPath, shortstatArgs...)
if err != nil && strings.Contains(err.Error(), "no merge base") {
// git >= 2.28 now returns an error if base and head have become unrelated.
// previously it would return the results of git diff --shortstat base head so let's try that...
shortstatArgs = []string{opts.BeforeCommitID, opts.AfterCommitID}
diff.NumFiles, diff.TotalAddition, diff.TotalDeletion, err = git.GetDiffShortStat(ctx, repoPath, shortstatArgs...)
}
if err != nil {
return nil, err
}
return diff, nil
}
// CommentAsDiff returns c.Patch as *Diff
func CommentAsDiff(c *models.Comment) (*Diff, error) {
diff, err := ParsePatch(setting.Git.MaxGitDiffLines,
setting.Git.MaxGitDiffLineCharacters, setting.Git.MaxGitDiffFiles, strings.NewReader(c.Patch), "")
if err != nil {
log.Error("Unable to parse patch: %v", err)
return nil, err
}
if len(diff.Files) == 0 {
return nil, fmt.Errorf("no file found for comment ID: %d", c.ID)
}
secs := diff.Files[0].Sections
if len(secs) == 0 {
return nil, fmt.Errorf("no sections found for comment ID: %d", c.ID)
}
return diff, nil
}
// CommentMustAsDiff executes AsDiff and logs the error instead of returning
func CommentMustAsDiff(c *models.Comment) *Diff {
if c == nil {
return nil
}
defer func() {
if err := recover(); err != nil {
log.Error("PANIC whilst retrieving diff for comment[%d] Error: %v\nStack: %s", c.ID, err, log.Stack(2))
}
}()
diff, err := CommentAsDiff(c)
if err != nil {
log.Warn("CommentMustAsDiff: %v", err)
}
return diff
}
// GetWhitespaceFlag returns git diff flag for treating whitespaces
func GetWhitespaceFlag(whiteSpaceBehavior string) string {
whitespaceFlags := map[string]string{
"ignore-all": "-w",
"ignore-change": "-b",
"ignore-eol": "--ignore-space-at-eol",
"": ""}
return whitespaceFlags[whiteSpaceBehavior]
}