first-commit

modules/git/grep.go

@@ -0,0 +1,149 @@
+// Copyright 2024 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package git
+
+import (
+	"bufio"
+	"bytes"
+	"context"
+	"errors"
+	"fmt"
+	"os"
+	"slices"
+	"strconv"
+	"strings"
+
+	"code.gitea.io/gitea/modules/util"
+)
+
+type GrepResult struct {
+	Filename    string
+	LineNumbers []int
+	LineCodes   []string
+}
+
+type GrepModeType string
+
+const (
+	GrepModeExact  GrepModeType = "exact"
+	GrepModeWords  GrepModeType = "words"
+	GrepModeRegexp GrepModeType = "regexp"
+)
+
+type GrepOptions struct {
+	RefName           string
+	MaxResultLimit    int
+	ContextLineNumber int
+	GrepMode          GrepModeType
+	MaxLineLength     int // the maximum length of a line to parse, exceeding chars will be truncated
+	PathspecList      []string
+}
+
+func GrepSearch(ctx context.Context, repo *Repository, search string, opts GrepOptions) ([]*GrepResult, error) {
+	stdoutReader, stdoutWriter, err := os.Pipe()
+	if err != nil {
+		return nil, fmt.Errorf("unable to create os pipe to grep: %w", err)
+	}
+	defer func() {
+		_ = stdoutReader.Close()
+		_ = stdoutWriter.Close()
+	}()
+
+	/*
+	 The output is like this ( "^@" means \x00):
+
+	 HEAD:.air.toml
+	 6^@bin = "gitea"
+
+	 HEAD:.changelog.yml
+	 2^@repo: go-gitea/gitea
+	*/
+	var results []*GrepResult
+	cmd := NewCommand("grep", "--null", "--break", "--heading", "--line-number", "--full-name")
+	cmd.AddOptionValues("--context", strconv.Itoa(opts.ContextLineNumber))
+	switch opts.GrepMode {
+	case GrepModeExact:
+		cmd.AddArguments("--fixed-strings")
+		cmd.AddOptionValues("-e", strings.TrimLeft(search, "-"))
+	case GrepModeRegexp:
+		cmd.AddArguments("--perl-regexp")
+		cmd.AddOptionValues("-e", strings.TrimLeft(search, "-"))
+	default: /* words */
+		words := strings.Fields(search)
+		cmd.AddArguments("--fixed-strings", "--ignore-case")
+		for i, word := range words {
+			cmd.AddOptionValues("-e", strings.TrimLeft(word, "-"))
+			if i < len(words)-1 {
+				cmd.AddOptionValues("--and")
+			}
+		}
+	}
+	cmd.AddDynamicArguments(util.IfZero(opts.RefName, "HEAD"))
+	cmd.AddDashesAndList(opts.PathspecList...)
+	opts.MaxResultLimit = util.IfZero(opts.MaxResultLimit, 50)
+	stderr := bytes.Buffer{}
+	err = cmd.Run(ctx, &RunOpts{
+		Dir:    repo.Path,
+		Stdout: stdoutWriter,
+		Stderr: &stderr,
+		PipelineFunc: func(ctx context.Context, cancel context.CancelFunc) error {
+			_ = stdoutWriter.Close()
+			defer stdoutReader.Close()
+
+			isInBlock := false
+			rd := bufio.NewReaderSize(stdoutReader, util.IfZero(opts.MaxLineLength, 16*1024))
+			var res *GrepResult
+			for {
+				lineBytes, isPrefix, err := rd.ReadLine()
+				if isPrefix {
+					lineBytes = slices.Clone(lineBytes)
+					for isPrefix && err == nil {
+						_, isPrefix, err = rd.ReadLine()
+					}
+				}
+				if len(lineBytes) == 0 && err != nil {
+					break
+				}
+				line := string(lineBytes) // the memory of lineBytes is mutable
+				if !isInBlock {
+					if _ /* ref */, filename, ok := strings.Cut(line, ":"); ok {
+						isInBlock = true
+						res = &GrepResult{Filename: filename}
+						results = append(results, res)
+					}
+					continue
+				}
+				if line == "" {
+					if len(results) >= opts.MaxResultLimit {
+						cancel()
+						break
+					}
+					isInBlock = false
+					continue
+				}
+				if line == "--" {
+					continue
+				}
+				if lineNum, lineCode, ok := strings.Cut(line, "\x00"); ok {
+					lineNumInt, _ := strconv.Atoi(lineNum)
+					res.LineNumbers = append(res.LineNumbers, lineNumInt)
+					res.LineCodes = append(res.LineCodes, lineCode)
+				}
+			}
+			return nil
+		},
+	})
+	// git grep exits by cancel (killed), usually it is caused by the limit of results
+	if IsErrorExitCode(err, -1) && stderr.Len() == 0 {
+		return results, nil
+	}
+	// git grep exits with 1 if no results are found
+	if IsErrorExitCode(err, 1) && stderr.Len() == 0 {
+		return nil, nil
+	}
+	if err != nil && !errors.Is(err, context.Canceled) {
+		return nil, fmt.Errorf("unable to run git grep: %w, stderr: %s", err, stderr.String())
+	}
+	return results, nil
+}