1 files changed, 135 insertions, 0 deletions

diff --git a/services/pull/lfs.go b/services/pull/lfs.go
new file mode 100644
index 0000000..ed03583
--- /dev/null
+++ b/services/pull/lfs.go
@@ -0,0 +1,135 @@
+// Copyright 2019 The Gitea Authors.
+// All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package pull
+
+import (
+	"bufio"
+	"context"
+	"io"
+	"strconv"
+	"sync"
+
+	"code.gitea.io/gitea/models/db"
+	git_model "code.gitea.io/gitea/models/git"
+	issues_model "code.gitea.io/gitea/models/issues"
+	"code.gitea.io/gitea/modules/git/pipeline"
+	"code.gitea.io/gitea/modules/lfs"
+	"code.gitea.io/gitea/modules/log"
+)
+
+// LFSPush pushes lfs objects referred to in new commits in the head repository from the base repository
+func 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
+		}
+	}
+}