// Copyright 2019 The Gitea Authors.// All rights reserved.// SPDX-License-Identifier: MIT package pull import (	"bufio"	"context"	"io"	"strconv"	"sync" 	"forgejo.org/models/db"	git_model "forgejo.org/models/git"	issues_model "forgejo.org/models/issues"	"forgejo.org/modules/git/pipeline"	"forgejo.org/modules/lfs"	"forgejo.org/modules/log") // LFSPush pushes lfs objects referred to in new commits in the head repository from the base repositoryfunc LFSPush(ctx context.Context, tmpBasePath, mergeHeadSHA, mergeBaseSHA string, pr *issues_model.PullRequest) error {	// Now we have to implement git lfs push	// git rev-list --objects --filter=blob:limit=1k HEAD --not base	// pass blob shas in to git cat-file --batch-check (possibly unnecessary)	// ensure only blobs and <=1k size then pass in to git cat-file --batch	// to read each sha and check each as a pointer	// Then if they are lfs -> add them to the baseRepo	revListReader, revListWriter := io.Pipe()	shasToCheckReader, shasToCheckWriter := io.Pipe()	catFileCheckReader, catFileCheckWriter := io.Pipe()	shasToBatchReader, shasToBatchWriter := io.Pipe()	catFileBatchReader, catFileBatchWriter := io.Pipe()	errChan := make(chan error, 1)	wg := sync.WaitGroup{}	wg.Add(6)	// Create the go-routines in reverse order. 	// 6. 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 associated with	// the head repo and add them to the base repo if so	go createLFSMetaObjectsFromCatFileBatch(db.DefaultContext, catFileBatchReader, &wg, pr) 	// 5. Take the shas of the blobs and batch read them	go pipeline.CatFileBatch(ctx, shasToBatchReader, catFileBatchWriter, &wg, tmpBasePath) 	// 4. From the provided objects restrict to blobs <=1k	go pipeline.BlobsLessThan1024FromCatFileBatchCheck(catFileCheckReader, shasToBatchWriter, &wg) 	// 3. Run batch-check on the objects retrieved from rev-list	go pipeline.CatFileBatchCheck(ctx, shasToCheckReader, catFileCheckWriter, &wg, tmpBasePath) 	// 2. Check each object retrieved rejecting those without names as they will be commits or trees	go pipeline.BlobsFromRevListObjects(revListReader, shasToCheckWriter, &wg) 	// 1. Run rev-list objects from mergeHead to mergeBase	go pipeline.RevListObjects(ctx, revListWriter, &wg, tmpBasePath, mergeHeadSHA, mergeBaseSHA, errChan) 	wg.Wait()	select {	case err, has := <-errChan:		if has {			return err		}	default:	}	return nil} func createLFSMetaObjectsFromCatFileBatch(ctx context.Context, catFileBatchReader *io.PipeReader, wg *sync.WaitGroup, pr *issues_model.PullRequest) {	defer wg.Done()	defer catFileBatchReader.Close() 	contentStore := lfs.NewContentStore() 	bufferedReader := bufio.NewReader(catFileBatchReader)	buf := make([]byte, 1025)	for {		// File descriptor line: sha		_, err := bufferedReader.ReadString(' ')		if err != nil {			_ = catFileBatchReader.CloseWithError(err)			break		}		// 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, _ := lfs.ReadPointerFromBuffer(pointerBuf)		if !pointer.IsValid() {			continue		} 		exist, _ := contentStore.Exists(pointer)		if !exist {			continue		} 		// Then we need to check that this pointer is in the db		if _, err := git_model.GetLFSMetaObjectByOid(ctx, pr.HeadRepoID, pointer.Oid); err != nil {			if err == git_model.ErrLFSObjectNotExist {				log.Warn("During merge of: %d in %-v, there is a pointer to LFS Oid: %s which although present in the LFS store is not associated with the head repo %-v", pr.Index, pr.BaseRepo, pointer.Oid, pr.HeadRepo)				continue			}			_ = catFileBatchReader.CloseWithError(err)			break		}		// OK we have a pointer that is associated with the head repo		// and is actually a file in the LFS		// Therefore it should be associated with the base repo		if _, err := git_model.NewLFSMetaObject(ctx, pr.BaseRepoID, pointer); err != nil {			_ = catFileBatchReader.CloseWithError(err)			break		}	}}