Some refactor on git diff and ignore getting commit information failed on migrating pull request review comments (#9996)

* Some refactor on git diff and ignore getting commit information failed on migrating pull request review comments

* fix test

* fix lint

* Change error log to warn

3 files changed, 3 insertions, 312 deletions

diff --git a/services/gitdiff/gitdiff.go b/services/gitdiff/gitdiff.go
index 6632f2d94e..6867f8e0a4 100644
--- a/services/gitdiff/gitdiff.go
+++ b/services/gitdiff/gitdiff.go
@@ -17,7 +17,6 @@ import (
 	"net/url"
 	"os"
 	"os/exec"
-	"regexp"
 	"sort"
 	"strconv"
 	"strings"
@@ -31,7 +30,6 @@ import (
 	"code.gitea.io/gitea/modules/setting"
 
 	"github.com/sergi/go-diff/diffmatchpatch"
-	"github.com/unknwon/com"
 	stdcharset "golang.org/x/net/html/charset"
 	"golang.org/x/text/transform"
 )
@@ -149,31 +147,8 @@ func (d *DiffLine) GetExpandDirection() DiffLineExpandDirection {
 	return DiffLineExpandSingle
 }
 
-// ParseDiffHunkString parse the diffhunk content and return
-func ParseDiffHunkString(diffhunk string) (leftLine, leftHunk, rightLine, righHunk int) {
-	ss := strings.Split(diffhunk, "@@")
-	ranges := strings.Split(ss[1][1:], " ")
-	leftRange := strings.Split(ranges[0], ",")
-	leftLine, _ = com.StrTo(leftRange[0][1:]).Int()
-	if len(leftRange) > 1 {
-		leftHunk, _ = com.StrTo(leftRange[1]).Int()
-	}
-	if len(ranges) > 1 {
-		rightRange := strings.Split(ranges[1], ",")
-		rightLine, _ = com.StrTo(rightRange[0]).Int()
-		if len(rightRange) > 1 {
-			righHunk, _ = com.StrTo(rightRange[1]).Int()
-		}
-	} else {
-		log.Warn("Parse line number failed: %v", diffhunk)
-		rightLine = leftLine
-		righHunk = leftHunk
-	}
-	return
-}
-
 func getDiffLineSectionInfo(treePath, line string, lastLeftIdx, lastRightIdx int) *DiffLineSectionInfo {
-	leftLine, leftHunk, rightLine, righHunk := ParseDiffHunkString(line)
+	leftLine, leftHunk, rightLine, righHunk := git.ParseDiffHunkString(line)
 
 	return &DiffLineSectionInfo{
 		Path:          treePath,
@@ -428,143 +403,6 @@ func (diff *Diff) NumFiles() int {
 	return len(diff.Files)
 }
 
-// Example: @@ -1,8 +1,9 @@ => [..., 1, 8, 1, 9]
-var hunkRegex = regexp.MustCompile(`^@@ -(?P<beginOld>[0-9]+)(,(?P<endOld>[0-9]+))? \+(?P<beginNew>[0-9]+)(,(?P<endNew>[0-9]+))? @@`)
-
-func isHeader(lof string) bool {
-	return strings.HasPrefix(lof, cmdDiffHead) || strings.HasPrefix(lof, "---") || strings.HasPrefix(lof, "+++")
-}
-
-// CutDiffAroundLine cuts a diff of a file in way that only the given line + numberOfLine above it will be shown
-// it also recalculates hunks and adds the appropriate headers to the new diff.
-// Warning: Only one-file diffs are allowed.
-func CutDiffAroundLine(originalDiff io.Reader, line int64, old bool, numbersOfLine int) string {
-	if line == 0 || numbersOfLine == 0 {
-		// no line or num of lines => no diff
-		return ""
-	}
-	scanner := bufio.NewScanner(originalDiff)
-	hunk := make([]string, 0)
-	// begin is the start of the hunk containing searched line
-	// end is the end of the hunk ...
-	// currentLine is the line number on the side of the searched line (differentiated by old)
-	// otherLine is the line number on the opposite side of the searched line (differentiated by old)
-	var begin, end, currentLine, otherLine int64
-	var headerLines int
-	for scanner.Scan() {
-		lof := scanner.Text()
-		// Add header to enable parsing
-		if isHeader(lof) {
-			hunk = append(hunk, lof)
-			headerLines++
-		}
-		if currentLine > line {
-			break
-		}
-		// Detect "hunk" with contains commented lof
-		if strings.HasPrefix(lof, "@@") {
-			// Already got our hunk. End of hunk detected!
-			if len(hunk) > headerLines {
-				break
-			}
-			// A map with named groups of our regex to recognize them later more easily
-			submatches := hunkRegex.FindStringSubmatch(lof)
-			groups := make(map[string]string)
-			for i, name := range hunkRegex.SubexpNames() {
-				if i != 0 && name != "" {
-					groups[name] = submatches[i]
-				}
-			}
-			if old {
-				begin = com.StrTo(groups["beginOld"]).MustInt64()
-				end = com.StrTo(groups["endOld"]).MustInt64()
-				// init otherLine with begin of opposite side
-				otherLine = com.StrTo(groups["beginNew"]).MustInt64()
-			} else {
-				begin = com.StrTo(groups["beginNew"]).MustInt64()
-				if groups["endNew"] != "" {
-					end = com.StrTo(groups["endNew"]).MustInt64()
-				} else {
-					end = 0
-				}
-				// init otherLine with begin of opposite side
-				otherLine = com.StrTo(groups["beginOld"]).MustInt64()
-			}
-			end += begin // end is for real only the number of lines in hunk
-			// lof is between begin and end
-			if begin <= line && end >= line {
-				hunk = append(hunk, lof)
-				currentLine = begin
-				continue
-			}
-		} else if len(hunk) > headerLines {
-			hunk = append(hunk, lof)
-			// Count lines in context
-			switch lof[0] {
-			case '+':
-				if !old {
-					currentLine++
-				} else {
-					otherLine++
-				}
-			case '-':
-				if old {
-					currentLine++
-				} else {
-					otherLine++
-				}
-			default:
-				currentLine++
-				otherLine++
-			}
-		}
-	}
-
-	// No hunk found
-	if currentLine == 0 {
-		return ""
-	}
-	// headerLines + hunkLine (1) = totalNonCodeLines
-	if len(hunk)-headerLines-1 <= numbersOfLine {
-		// No need to cut the hunk => return existing hunk
-		return strings.Join(hunk, "\n")
-	}
-	var oldBegin, oldNumOfLines, newBegin, newNumOfLines int64
-	if old {
-		oldBegin = currentLine
-		newBegin = otherLine
-	} else {
-		oldBegin = otherLine
-		newBegin = currentLine
-	}
-	// headers + hunk header
-	newHunk := make([]string, headerLines)
-	// transfer existing headers
-	copy(newHunk, hunk[:headerLines])
-	// transfer last n lines
-	newHunk = append(newHunk, hunk[len(hunk)-numbersOfLine-1:]...)
-	// calculate newBegin, ... by counting lines
-	for i := len(hunk) - 1; i >= len(hunk)-numbersOfLine; i-- {
-		switch hunk[i][0] {
-		case '+':
-			newBegin--
-			newNumOfLines++
-		case '-':
-			oldBegin--
-			oldNumOfLines++
-		default:
-			oldBegin--
-			newBegin--
-			newNumOfLines++
-			oldNumOfLines++
-		}
-	}
-	// construct the new hunk header
-	newHunk[headerLines] = fmt.Sprintf("@@ -%d,%d +%d,%d @@",
-		oldBegin, oldNumOfLines, newBegin, newNumOfLines)
-	return strings.Join(newHunk, "\n")
-}
-
 const cmdDiffHead = "diff --git "
 
 // ParsePatch builds a Diff object from a io.Reader and some
@@ -881,82 +719,6 @@ func GetDiffRangeWithWhitespaceBehavior(repoPath, beforeCommitID, afterCommitID
 	return diff, nil
 }
 
-// RawDiffType type of a raw diff.
-type RawDiffType string
-
-// RawDiffType possible values.
-const (
-	RawDiffNormal RawDiffType = "diff"
-	RawDiffPatch  RawDiffType = "patch"
-)
-
-// GetRawDiff dumps diff results of repository in given commit ID to io.Writer.
-// TODO: move this function to gogits/git-module
-func GetRawDiff(repoPath, commitID string, diffType RawDiffType, writer io.Writer) error {
-	return GetRawDiffForFile(repoPath, "", commitID, diffType, "", writer)
-}
-
-// GetRawDiffForFile dumps diff results of file in given commit ID to io.Writer.
-// TODO: move this function to gogits/git-module
-func GetRawDiffForFile(repoPath, startCommit, endCommit string, diffType RawDiffType, file string, writer io.Writer) error {
-	repo, err := git.OpenRepository(repoPath)
-	if err != nil {
-		return fmt.Errorf("OpenRepository: %v", err)
-	}
-	defer repo.Close()
-
-	commit, err := repo.GetCommit(endCommit)
-	if err != nil {
-		return fmt.Errorf("GetCommit: %v", err)
-	}
-	fileArgs := make([]string, 0)
-	if len(file) > 0 {
-		fileArgs = append(fileArgs, "--", file)
-	}
-	// FIXME: graceful: These commands should have a timeout
-	ctx, cancel := context.WithCancel(git.DefaultContext)
-	defer cancel()
-
-	var cmd *exec.Cmd
-	switch diffType {
-	case RawDiffNormal:
-		if len(startCommit) != 0 {
-			cmd = exec.CommandContext(ctx, git.GitExecutable, append([]string{"diff", "-M", startCommit, endCommit}, fileArgs...)...)
-		} else if commit.ParentCount() == 0 {
-			cmd = exec.CommandContext(ctx, git.GitExecutable, append([]string{"show", endCommit}, fileArgs...)...)
-		} else {
-			c, _ := commit.Parent(0)
-			cmd = exec.CommandContext(ctx, git.GitExecutable, append([]string{"diff", "-M", c.ID.String(), endCommit}, fileArgs...)...)
-		}
-	case RawDiffPatch:
-		if len(startCommit) != 0 {
-			query := fmt.Sprintf("%s...%s", endCommit, startCommit)
-			cmd = exec.CommandContext(ctx, git.GitExecutable, append([]string{"format-patch", "--no-signature", "--stdout", "--root", query}, fileArgs...)...)
-		} else if commit.ParentCount() == 0 {
-			cmd = exec.CommandContext(ctx, git.GitExecutable, append([]string{"format-patch", "--no-signature", "--stdout", "--root", endCommit}, fileArgs...)...)
-		} else {
-			c, _ := commit.Parent(0)
-			query := fmt.Sprintf("%s...%s", endCommit, c.ID.String())
-			cmd = exec.CommandContext(ctx, git.GitExecutable, append([]string{"format-patch", "--no-signature", "--stdout", query}, fileArgs...)...)
-		}
-	default:
-		return fmt.Errorf("invalid diffType: %s", diffType)
-	}
-
-	stderr := new(bytes.Buffer)
-
-	cmd.Dir = repoPath
-	cmd.Stdout = writer
-	cmd.Stderr = stderr
-	pid := process.GetManager().Add(fmt.Sprintf("GetRawDiffForFile: [repo_path: %s]", repoPath), cancel)
-	defer process.GetManager().Remove(pid)
-
-	if err = cmd.Run(); err != nil {
-		return fmt.Errorf("Run: %v - %s", err, stderr)
-	}
-	return nil
-}
-
 // GetDiffCommit builds a Diff representing the given commitID.
 func GetDiffCommit(repoPath, commitID string, maxLines, maxLineCharacters, maxFiles int) (*Diff, error) {
 	return GetDiffRange(repoPath, "", commitID, maxLines, maxLineCharacters, maxFiles)
diff --git a/services/gitdiff/gitdiff_test.go b/services/gitdiff/gitdiff_test.go
index 58604d97c4..efdf439933 100644
--- a/services/gitdiff/gitdiff_test.go
+++ b/services/gitdiff/gitdiff_test.go
@@ -41,68 +41,6 @@ func TestDiffToHTML(t *testing.T) {
 	}, DiffLineDel))
 }
 
-const exampleDiff = `diff --git a/README.md b/README.md
---- a/README.md
-+++ b/README.md
-@@ -1,3 +1,6 @@
- # gitea-github-migrator
-+
-+ Build Status
-- Latest Release
- Docker Pulls
-+ cut off
-+ cut off`
-
-func TestCutDiffAroundLine(t *testing.T) {
-	result := CutDiffAroundLine(strings.NewReader(exampleDiff), 4, false, 3)
-	resultByLine := strings.Split(result, "\n")
-	assert.Len(t, resultByLine, 7)
-	// Check if headers got transferred
-	assert.Equal(t, "diff --git a/README.md b/README.md", resultByLine[0])
-	assert.Equal(t, "--- a/README.md", resultByLine[1])
-	assert.Equal(t, "+++ b/README.md", resultByLine[2])
-	// Check if hunk header is calculated correctly
-	assert.Equal(t, "@@ -2,2 +3,2 @@", resultByLine[3])
-	// Check if line got transferred
-	assert.Equal(t, "+ Build Status", resultByLine[4])
-
-	// Must be same result as before since old line 3 == new line 5
-	newResult := CutDiffAroundLine(strings.NewReader(exampleDiff), 3, true, 3)
-	assert.Equal(t, result, newResult, "Must be same result as before since old line 3 == new line 5")
-
-	newResult = CutDiffAroundLine(strings.NewReader(exampleDiff), 6, false, 300)
-	assert.Equal(t, exampleDiff, newResult)
-
-	emptyResult := CutDiffAroundLine(strings.NewReader(exampleDiff), 6, false, 0)
-	assert.Empty(t, emptyResult)
-
-	// Line is out of scope
-	emptyResult = CutDiffAroundLine(strings.NewReader(exampleDiff), 434, false, 0)
-	assert.Empty(t, emptyResult)
-}
-
-func BenchmarkCutDiffAroundLine(b *testing.B) {
-	for n := 0; n < b.N; n++ {
-		CutDiffAroundLine(strings.NewReader(exampleDiff), 3, true, 3)
-	}
-}
-
-func ExampleCutDiffAroundLine() {
-	const diff = `diff --git a/README.md b/README.md
---- a/README.md
-+++ b/README.md
-@@ -1,3 +1,6 @@
- # gitea-github-migrator
-+
-+ Build Status
-- Latest Release
- Docker Pulls
-+ cut off
-+ cut off`
-	result := CutDiffAroundLine(strings.NewReader(diff), 4, false, 3)
-	println(result)
-}
-
 func TestParsePatch(t *testing.T) {
 	var diff = `diff --git "a/README.md" "b/README.md"
 --- a/README.md
@@ -209,11 +147,3 @@ func TestGetDiffRangeWithWhitespaceBehavior(t *testing.T) {
 		}
 	}
 }
-
-func TestParseDiffHunkString(t *testing.T) {
-	leftLine, leftHunk, rightLine, rightHunk := ParseDiffHunkString("@@ -19,3 +19,5 @@ AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER")
-	assert.EqualValues(t, 19, leftLine)
-	assert.EqualValues(t, 3, leftHunk)
-	assert.EqualValues(t, 19, rightLine)
-	assert.EqualValues(t, 5, rightHunk)
-}
diff --git a/services/pull/review.go b/services/pull/review.go
index 2bc8240230..2b7c9e8646 100644
--- a/services/pull/review.go
+++ b/services/pull/review.go
@@ -14,7 +14,6 @@ import (
 	"code.gitea.io/gitea/modules/git"
 	"code.gitea.io/gitea/modules/notification"
 	"code.gitea.io/gitea/modules/setting"
-	"code.gitea.io/gitea/services/gitdiff"
 )
 
 // CreateCodeComment creates a comment on the code line
@@ -140,10 +139,10 @@ func createCodeComment(doer *models.User, repo *models.Repository, issue *models
 			return nil, fmt.Errorf("GetRefCommitID[%s]: %v", pr.GetGitRefName(), err)
 		}
 		patchBuf := new(bytes.Buffer)
-		if err := gitdiff.GetRawDiffForFile(gitRepo.Path, pr.MergeBase, headCommitID, gitdiff.RawDiffNormal, treePath, patchBuf); err != nil {
+		if err := git.GetRepoRawDiffForFile(gitRepo, pr.MergeBase, headCommitID, git.RawDiffNormal, treePath, patchBuf); err != nil {
 			return nil, fmt.Errorf("GetRawDiffForLine[%s, %s, %s, %s]: %v", err, gitRepo.Path, pr.MergeBase, headCommitID, treePath)
 		}
-		patch = gitdiff.CutDiffAroundLine(patchBuf, int64((&models.Comment{Line: line}).UnsignedLine()), line < 0, setting.UI.CodeCommentLines)
+		patch = git.CutDiffAroundLine(patchBuf, int64((&models.Comment{Line: line}).UnsignedLine()), line < 0, setting.UI.CodeCommentLines)
 	}
 	return models.CreateComment(&models.CreateCommentOptions{
 		Type:      models.CommentTypeCode,