Refactor cat-file batch operations and support --batch-command approach (#35775)

Replace #34651 and address more problems including fix framework bugs and changing to QueryInfo and QueryContent calls.

---------

Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>

modules/git/catfile_batch.go

@@ -0,0 +1,52 @@
+// Copyright 2026 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package git
+
+import (
+	"context"
+	"io"
+)
+
+type BufferedReader interface {
+	io.Reader
+	Buffered() int
+	Peek(n int) ([]byte, error)
+	Discard(n int) (int, error)
+	ReadString(sep byte) (string, error)
+	ReadSlice(sep byte) ([]byte, error)
+	ReadBytes(sep byte) ([]byte, error)
+}
+
+type CatFileObject struct {
+	ID   string
+	Type string
+	Size int64
+}
+
+type CatFileBatch interface {
+	// QueryInfo queries the object info from the git repository by its object name using "git cat-file --batch" family commands.
+	// "git cat-file" accepts "<rev>" for the object name, it can be a ref name, object id, etc. https://git-scm.com/docs/gitrevisions
+	// In Gitea, we only use the simple ref name or object id, no other complex rev syntax like "suffix" or "git describe" although they are supported by git.
+	QueryInfo(obj string) (*CatFileObject, error)
+
+	// QueryContent is similar to QueryInfo, it queries the object info and additionally returns a reader for its content.
+	// FIXME: this design still follows the old pattern: the returned BufferedReader is very fragile,
+	// callers should carefully maintain its lifecycle and discard all unread data.
+	// TODO: It needs to be refactored to a fully managed Reader stream in the future, don't let callers manually Close or Discard
+	QueryContent(obj string) (*CatFileObject, BufferedReader, error)
+}
+
+type CatFileBatchCloser interface {
+	CatFileBatch
+	Close()
+}
+
+// NewBatch creates a "batch object provider (CatFileBatch)" for the given repository path to retrieve object info and content efficiently.
+// The CatFileBatch and the readers create by it should only be used in the same goroutine.
+func NewBatch(ctx context.Context, repoPath string) (CatFileBatchCloser, error) {
+	if DefaultFeatures().SupportCatFileBatchCommand {
+		return newCatFileBatchCommand(ctx, repoPath)
+	}
+	return newCatFileBatchLegacy(ctx, repoPath)
+}