refactor: make git package handle all git operations (#38543)

before: gitrepo vs git packages
after: git package fully handle all git operations

by the way, use `WithRepo(repo)` instead of `WithDir(repo.Path)` to hide
path details.

benefits:

1. remove all unnecessary wrappers, developers no need to struggle with
"which package should be used"
2. simplify code, RepositoryFacade can (will) be used everywhere, all
"path" details are (will be) hidden

modules/git/repo.go

@@ -13,6 +13,7 @@ import (
 	"path/filepath"
 	"strconv"
 	"strings"
+	"sync"
 	"time"
 
 	"gitea.dev/modules/git/gitcmd"
@@ -24,13 +25,20 @@ import (
 type RepositoryFacade = gitcmd.RepositoryFacade
 
 type RepositoryBase struct {
-	Path string // absolute path
+	// TODO: refactor it to a private field "localPath" in the future
+	// * for repo accessing purpose, in most causes, use "WithRepo", or RepoLocalPath(repo) if the local path must be used
+	// * for error handling & logging purpose, it needs to introduce a new function "git.RepoLogName()" to handle various cases
+	Path string
 
 	LastCommitCache *LastCommitCache
 
 	repoFacade        RepositoryFacade
 	tagCache          *ObjectCache[*Tag]
 	objectFormatCache ObjectFormat
+
+	mu                 sync.Mutex
+	catFileBatchCloser CatFileBatchCloser
+	catFileBatchInUse  bool
 }
 
 var _ gitcmd.RepositoryFacade = (*Repository)(nil)
@@ -78,6 +86,14 @@ func (repo *Repository) Close() error {
 	}
 	repo.LastCommitCache = nil
 	repo.tagCache = nil
+
+	repo.mu.Lock()
+	defer repo.mu.Unlock()
+	if repo.catFileBatchCloser != nil {
+		repo.catFileBatchCloser.Close()
+		repo.catFileBatchCloser = nil
+		repo.catFileBatchInUse = false
+	}
 	return repo.closeInternal()
 }
 
@@ -87,8 +103,8 @@ func IsRepoURLAccessible(ctx context.Context, url string) bool {
 	return err == nil
 }
 
-// InitRepository initializes a new Git repository.
-func InitRepository(ctx context.Context, repoPath string, bare bool, objectFormatName string) error {
+// InitRepositoryLocal initializes a new Git repository.
+func InitRepositoryLocal(ctx context.Context, repoPath string, bare bool, objectFormatName string) error {
 	err := os.MkdirAll(repoPath, os.ModePerm)
 	if err != nil {
 		return err
@@ -115,7 +131,7 @@ func (repo *Repository) IsEmpty(ctx context.Context) (bool, error) {
 	stdout, _, err := gitcmd.NewCommand().
 		AddOptionFormat("--git-dir=%s", repo.Path).
 		AddArguments("rev-list", "-n", "1", "--all").
-		WithDir(repo.Path).
+		WithRepo(repo).
 		RunStdString(ctx)
 	if err != nil {
 		if (gitcmd.IsErrorExitCode(err, 1) && err.Stderr() == "") || gitcmd.IsErrorExitCode(err, 129) {
@@ -255,3 +271,41 @@ func Push(ctx context.Context, repoPath string, opts PushOptions) error {
 
 	return nil
 }
+
+// CatFileBatch obtains a "batch object provider" for this repository.
+// It reuses an existing one if available, otherwise creates a new one.
+func (repo *Repository) CatFileBatch(ctx context.Context) (_ CatFileBatch, closeFunc func(), err error) {
+	repo.mu.Lock()
+	defer repo.mu.Unlock()
+
+	if repo.catFileBatchCloser != nil && !repo.catFileBatchInUse {
+		if ctx != repo.catFileBatchCloser.Context() {
+			repo.catFileBatchCloser.Close()
+			repo.catFileBatchCloser = nil
+			repo.catFileBatchInUse = false
+		}
+	}
+
+	if repo.catFileBatchCloser == nil {
+		repo.catFileBatchCloser, err = NewBatch(ctx, repo)
+		if err != nil {
+			repo.catFileBatchCloser = nil // otherwise it is "interface(nil)" and will cause wrong logic
+			return nil, nil, err
+		}
+	}
+
+	if !repo.catFileBatchInUse {
+		repo.catFileBatchInUse = true
+		return CatFileBatch(repo.catFileBatchCloser), func() {
+			repo.mu.Lock()
+			defer repo.mu.Unlock()
+			repo.catFileBatchInUse = false
+		}, nil
+	}
+
+	tempBatch, err := NewBatch(ctx, repo)
+	if err != nil {
+		return nil, nil, err
+	}
+	return tempBatch, tempBatch.Close, nil
+}