// Copyright 2020 The Gitea Authors. All rights reserved.// SPDX-License-Identifier: MIT package git import (	"bufio"	"bytes"	"context"	"fmt"	"io"	"os"	"regexp"	"strconv"	"strings" 	"code.gitea.io/gitea/modules/log") // 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.func GetRawDiff(repo *Repository, commitID string, diffType RawDiffType, writer io.Writer) error {	return GetRepoRawDiffForFile(repo, "", commitID, diffType, "", writer)} // GetReverseRawDiff dumps the reverse diff results of repository in given commit ID to io.Writer.func GetReverseRawDiff(ctx context.Context, repoPath, commitID string, writer io.Writer) error {	stderr := new(bytes.Buffer)	cmd := NewCommand(ctx, "show", "--pretty=format:revert %H%n", "-R").AddDynamicArguments(commitID)	if err := cmd.Run(&RunOpts{		Dir:    repoPath,		Stdout: writer,		Stderr: stderr,	}); err != nil {		return fmt.Errorf("Run: %w - %s", err, stderr)	}	return nil} // GetRepoRawDiffForFile dumps diff results of file in given commit ID to io.Writer according given repositoryfunc GetRepoRawDiffForFile(repo *Repository, startCommit, endCommit string, diffType RawDiffType, file string, writer io.Writer) error {	commit, err := repo.GetCommit(endCommit)	if err != nil {		return err	}	var files []string	if len(file) > 0 {		files = append(files, file)	} 	cmd := NewCommand(repo.Ctx)	switch diffType {	case RawDiffNormal:		if len(startCommit) != 0 {			cmd.AddArguments("diff", "-M").AddDynamicArguments(startCommit, endCommit).AddDashesAndList(files...)		} else if commit.ParentCount() == 0 {			cmd.AddArguments("show").AddDynamicArguments(endCommit).AddDashesAndList(files...)		} else {			c, _ := commit.Parent(0)			cmd.AddArguments("diff", "-M").AddDynamicArguments(c.ID.String(), endCommit).AddDashesAndList(files...)		}	case RawDiffPatch:		if len(startCommit) != 0 {			query := fmt.Sprintf("%s...%s", endCommit, startCommit)			cmd.AddArguments("format-patch", "--no-signature", "--stdout", "--root").AddDynamicArguments(query).AddDashesAndList(files...)		} else if commit.ParentCount() == 0 {			cmd.AddArguments("format-patch", "--no-signature", "--stdout", "--root").AddDynamicArguments(endCommit).AddDashesAndList(files...)		} else {			c, _ := commit.Parent(0)			query := fmt.Sprintf("%s...%s", endCommit, c.ID.String())			cmd.AddArguments("format-patch", "--no-signature", "--stdout").AddDynamicArguments(query).AddDashesAndList(files...)		}	default:		return fmt.Errorf("invalid diffType: %s", diffType)	} 	stderr := new(bytes.Buffer)	if err = cmd.Run(&RunOpts{		Dir:    repo.Path,		Stdout: writer,		Stderr: stderr,	}); err != nil {		return fmt.Errorf("Run: %w - %s", err, stderr)	}	return nil} // ParseDiffHunkString parse the diffhunk content and returnfunc ParseDiffHunkString(diffhunk string) (leftLine, leftHunk, rightLine, righHunk int) {	ss := strings.Split(diffhunk, "@@")	ranges := strings.Split(ss[1][1:], " ")	leftRange := strings.Split(ranges[0], ",")	leftLine, _ = strconv.Atoi(leftRange[0][1:])	if len(leftRange) > 1 {		leftHunk, _ = strconv.Atoi(leftRange[1])	}	if len(ranges) > 1 {		rightRange := strings.Split(ranges[1], ",")		rightLine, _ = strconv.Atoi(rightRange[0])		if len(rightRange) > 1 {			righHunk, _ = strconv.Atoi(rightRange[1])		}	} else {		log.Debug("Parse line number failed: %v", diffhunk)		rightLine = leftLine		righHunk = leftHunk	}	return leftLine, leftHunk, rightLine, righHunk} // 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]+))? @@`) const cmdDiffHead = "diff --git " func isHeader(lof string, inHunk bool) bool {	return strings.HasPrefix(lof, cmdDiffHead) || (!inHunk && (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, error) {	if line == 0 || numbersOfLine == 0 {		// no line or num of lines => no diff		return "", nil	} 	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 	inHunk := false 	for scanner.Scan() {		lof := scanner.Text()		// Add header to enable parsing 		if isHeader(lof, inHunk) {			if strings.HasPrefix(lof, cmdDiffHead) {				inHunk = false			}			hunk = append(hunk, lof)			headerLines++		}		if currentLine > line {			break		}		// Detect "hunk" with contains commented lof		if strings.HasPrefix(lof, "@@") {			inHunk = true			// 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, _ = strconv.ParseInt(groups["beginOld"], 10, 64)				end, _ = strconv.ParseInt(groups["endOld"], 10, 64)				// init otherLine with begin of opposite side				otherLine, _ = strconv.ParseInt(groups["beginNew"], 10, 64)			} else {				begin, _ = strconv.ParseInt(groups["beginNew"], 10, 64)				if groups["endNew"] != "" {					end, _ = strconv.ParseInt(groups["endNew"], 10, 64)				} else {					end = 0				}				// init otherLine with begin of opposite side				otherLine, _ = strconv.ParseInt(groups["beginOld"], 10, 64)			}			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++				}			case '\\':				// FIXME: handle `\ No newline at end of file`			default:				currentLine++				otherLine++			}		}	}	if err := scanner.Err(); err != nil {		return "", err	} 	// No hunk found	if currentLine == 0 {		return "", nil	}	// headerLines + hunkLine (1) = totalNonCodeLines	if len(hunk)-headerLines-1 <= numbersOfLine {		// No need to cut the hunk => return existing hunk		return strings.Join(hunk, "\n"), nil	}	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"), nil} // GetAffectedFiles returns the affected files between two commitsfunc GetAffectedFiles(repo *Repository, oldCommitID, newCommitID string, env []string) ([]string, error) {	stdoutReader, stdoutWriter, err := os.Pipe()	if err != nil {		log.Error("Unable to create os.Pipe for %s", repo.Path)		return nil, err	}	defer func() {		_ = stdoutReader.Close()		_ = stdoutWriter.Close()	}() 	affectedFiles := make([]string, 0, 32) 	// Run `git diff --name-only` to get the names of the changed files	err = NewCommand(repo.Ctx, "diff", "--name-only").AddDynamicArguments(oldCommitID, newCommitID).		Run(&RunOpts{			Env:    env,			Dir:    repo.Path,			Stdout: stdoutWriter,			PipelineFunc: func(ctx context.Context, cancel context.CancelFunc) error {				// Close the writer end of the pipe to begin processing				_ = stdoutWriter.Close()				defer func() {					// Close the reader on return to terminate the git command if necessary					_ = stdoutReader.Close()				}()				// Now scan the output from the command				scanner := bufio.NewScanner(stdoutReader)				for scanner.Scan() {					path := strings.TrimSpace(scanner.Text())					if len(path) == 0 {						continue					}					affectedFiles = append(affectedFiles, path)				}				return scanner.Err()			},		})	if err != nil {		log.Error("Unable to get affected files for commits from %s to %s in %s: %v", oldCommitID, newCommitID, repo.Path, err)	} 	return affectedFiles, err}