// Copyright 2021 The Gitea Authors. All rights reserved.// SPDX-License-Identifier: MIT package lfs import (	"bufio"	"context"	"io"	"strconv"	"strings"	"sync" 	"forgejo.org/modules/git"	"forgejo.org/modules/git/pipeline") // SearchPointerBlobs scans the whole repository for LFS pointer filesfunc SearchPointerBlobs(ctx context.Context, repo *git.Repository, pointerChan chan<- PointerBlob, errChan chan<- error) {	basePath := repo.Path 	catFileCheckReader, catFileCheckWriter := io.Pipe()	shasToBatchReader, shasToBatchWriter := io.Pipe()	catFileBatchReader, catFileBatchWriter := io.Pipe() 	wg := sync.WaitGroup{}	wg.Add(4) 	// Create the go-routines in reverse order. 	// 4. Take the output of cat-file --batch and check if each file in turn	// to see if they're pointers to files in the LFS store	go createPointerResultsFromCatFileBatch(ctx, catFileBatchReader, &wg, pointerChan) 	// 3. Take the shas of the blobs and batch read them	go pipeline.CatFileBatch(ctx, shasToBatchReader, catFileBatchWriter, &wg, basePath) 	// 2. From the provided objects restrict to blobs <=1k	go pipeline.BlobsLessThan1024FromCatFileBatchCheck(catFileCheckReader, shasToBatchWriter, &wg) 	// 1. Run batch-check on all objects in the repository	go pipeline.CatFileBatchCheckAllObjects(ctx, catFileCheckWriter, &wg, basePath, errChan)	wg.Wait() 	close(pointerChan)	close(errChan)} func createPointerResultsFromCatFileBatch(ctx context.Context, catFileBatchReader *io.PipeReader, wg *sync.WaitGroup, pointerChan chan<- PointerBlob) {	defer wg.Done()	defer catFileBatchReader.Close() 	bufferedReader := bufio.NewReader(catFileBatchReader)	buf := make([]byte, 1025) loop:	for {		select {		case <-ctx.Done():			break loop		default:		} 		// File descriptor line: sha		sha, err := bufferedReader.ReadString(' ')		if err != nil {			_ = catFileBatchReader.CloseWithError(err)			break		}		sha = strings.TrimSpace(sha)		// Throw away the blob		if _, err := bufferedReader.ReadString(' '); err != nil {			_ = catFileBatchReader.CloseWithError(err)			break		}		sizeStr, err := bufferedReader.ReadString('\n')		if err != nil {			_ = catFileBatchReader.CloseWithError(err)			break		}		size, err := strconv.Atoi(sizeStr[:len(sizeStr)-1])		if err != nil {			_ = catFileBatchReader.CloseWithError(err)			break		}		pointerBuf := buf[:size+1]		if _, err := io.ReadFull(bufferedReader, pointerBuf); err != nil {			_ = catFileBatchReader.CloseWithError(err)			break		}		pointerBuf = pointerBuf[:size]		// Now we need to check if the pointerBuf is an LFS pointer		pointer, _ := ReadPointerFromBuffer(pointerBuf)		if !pointer.IsValid() {			continue		} 		pointerChan <- PointerBlob{Hash: sha, Pointer: pointer}	}}