enable literal string for code search (#33590)

Close: #33588

---------

Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>
Co-authored-by: Giteabot <teabot@gitea.io>

modules/indexer/code/gitgrep/gitgrep.go

@@ -0,0 +1,59 @@
+// Copyright 2025 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package gitgrep
+
+import (
+	"context"
+	"fmt"
+	"strings"
+
+	"code.gitea.io/gitea/modules/git"
+	code_indexer "code.gitea.io/gitea/modules/indexer/code"
+	"code.gitea.io/gitea/modules/setting"
+)
+
+func indexSettingToGitGrepPathspecList() (list []string) {
+	for _, expr := range setting.Indexer.IncludePatterns {
+		list = append(list, ":(glob)"+expr.PatternString())
+	}
+	for _, expr := range setting.Indexer.ExcludePatterns {
+		list = append(list, ":(glob,exclude)"+expr.PatternString())
+	}
+	return list
+}
+
+func PerformSearch(ctx context.Context, page int, repoID int64, gitRepo *git.Repository, ref git.RefName, keyword string, isFuzzy bool) (searchResults []*code_indexer.Result, total int, err error) {
+	// TODO: it should also respect ParseKeywordAsPhrase and clarify the "fuzzy" behavior
+	res, err := git.GrepSearch(ctx, gitRepo, keyword, git.GrepOptions{
+		ContextLineNumber: 1,
+		IsFuzzy:           isFuzzy,
+		RefName:           ref.String(),
+		PathspecList:      indexSettingToGitGrepPathspecList(),
+	})
+	if err != nil {
+		// TODO: if no branch exists, it reports: exit status 128, fatal: this operation must be run in a work tree.
+		return nil, 0, fmt.Errorf("git.GrepSearch: %w", err)
+	}
+	commitID, err := gitRepo.GetRefCommitID(ref.String())
+	if err != nil {
+		return nil, 0, fmt.Errorf("gitRepo.GetRefCommitID: %w", err)
+	}
+
+	total = len(res)
+	pageStart := min((page-1)*setting.UI.RepoSearchPagingNum, len(res))
+	pageEnd := min(page*setting.UI.RepoSearchPagingNum, len(res))
+	res = res[pageStart:pageEnd]
+	for _, r := range res {
+		searchResults = append(searchResults, &code_indexer.Result{
+			RepoID:   repoID,
+			Filename: r.Filename,
+			CommitID: commitID,
+			// UpdatedUnix: not supported yet
+			// Language:    not supported yet
+			// Color:       not supported yet
+			Lines: code_indexer.HighlightSearchResultCode(r.Filename, "", r.LineNumbers, strings.Join(r.LineCodes, "\n")),
+		})
+	}
+	return searchResults, total, nil
+}

modules/indexer/code/gitgrep/gitgrep_test.go

@@ -0,0 +1,19 @@
+// Copyright 2024 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package gitgrep
+
+import (
+	"testing"
+
+	"code.gitea.io/gitea/modules/setting"
+	"code.gitea.io/gitea/modules/test"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestIndexSettingToGitGrepPathspecList(t *testing.T) {
+	defer test.MockVariableValue(&setting.Indexer.IncludePatterns, setting.IndexerGlobFromString("a"))()
+	defer test.MockVariableValue(&setting.Indexer.ExcludePatterns, setting.IndexerGlobFromString("b"))()
+	assert.Equal(t, []string{":(glob)a", ":(glob,exclude)b"}, indexSettingToGitGrepPathspecList())
+}