check: Simplify blob status tracking

UnusedBlobs now directly reads the list of existing blobs from the
repository index. This removes the need for the blobStatusExists flag,
which in turn allows converting the blobRefs map into a BlobSet.

cmd/restic/cmd_check.go

@@ -255,7 +255,7 @@ func runCheck(opts CheckOptions, gopts GlobalOptions, args []string) error {
 	}
 
 	if opts.CheckUnused {
-		for _, id := range chkr.UnusedBlobs() {
+		for _, id := range chkr.UnusedBlobs(gopts.ctx) {
 			Verbosef("unused blob %v\n", id)
 			errorsFound = true
 		}

internal/checker/checker.go

@@ -25,8 +25,7 @@ type Checker struct {
 	packs    map[restic.ID]int64
 	blobRefs struct {
 		sync.Mutex
-		// see flags below
-		M map[restic.BlobHandle]blobStatus
+		M restic.BlobSet
 	}
 
 	masterIndex *repository.MasterIndex
@@ -34,13 +33,6 @@ type Checker struct {
 	repo restic.Repository
 }
 
-type blobStatus uint8
-
-const (
-	blobStatusExists blobStatus = 1 << iota
-	blobStatusReferenced
-)
-
 // New returns a new checker which runs on repo.
 func New(repo restic.Repository) *Checker {
 	c := &Checker{
@@ -49,7 +41,7 @@ func New(repo restic.Repository) *Checker {
 		repo:        repo,
 	}
 
-	c.blobRefs.M = make(map[restic.BlobHandle]blobStatus)
+	c.blobRefs.M = restic.NewBlobSet()
 
 	return c
 }
@@ -162,8 +154,6 @@ func (c *Checker) LoadIndex(ctx context.Context) (hints []error, errs []error) {
 			debug.Log("process blobs")
 			cnt := 0
 			for blob := range res.Index.Each(wgCtx) {
-				h := restic.BlobHandle{ID: blob.ID, Type: blob.Type}
-				c.blobRefs.M[h] = blobStatusExists
 				cnt++
 
 				if _, ok := packToIndex[blob.PackID]; !ok {
@@ -529,9 +519,9 @@ func (c *Checker) filterTrees(ctx context.Context, backlog restic.IDs, loaderCha
 			// even when a file references a tree blob
 			c.blobRefs.Lock()
 			h := restic.BlobHandle{ID: nextTreeID, Type: restic.TreeBlob}
-			status := c.blobRefs.M[h]
+			blobReferenced := c.blobRefs.M.Has(h)
 			c.blobRefs.Unlock()
-			if (status & blobStatusReferenced) != 0 {
+			if blobReferenced {
 				continue
 			}
 
@@ -552,7 +542,7 @@ func (c *Checker) filterTrees(ctx context.Context, backlog restic.IDs, loaderCha
 			loadCh = nil
 			c.blobRefs.Lock()
 			h := restic.BlobHandle{ID: nextTreeID, Type: restic.TreeBlob}
-			c.blobRefs.M[h] |= blobStatusReferenced
+			c.blobRefs.M.Insert(h)
 			c.blobRefs.Unlock()
 
 		case j, ok := <-inCh:
@@ -687,7 +677,7 @@ func (c *Checker) checkTree(id restic.ID, tree *restic.Tree) (errs []error) {
 	for _, blobID := range blobs {
 		c.blobRefs.Lock()
 		h := restic.BlobHandle{ID: blobID, Type: restic.DataBlob}
-		c.blobRefs.M[h] |= blobStatusReferenced
+		c.blobRefs.M.Insert(h)
 		debug.Log("blob %v is referenced", blobID)
 		c.blobRefs.Unlock()
 	}
@@ -696,15 +686,19 @@ func (c *Checker) checkTree(id restic.ID, tree *restic.Tree) (errs []error) {
 }
 
 // UnusedBlobs returns all blobs that have never been referenced.
-func (c *Checker) UnusedBlobs() (blobs restic.BlobHandles) {
+func (c *Checker) UnusedBlobs(ctx context.Context) (blobs restic.BlobHandles) {
 	c.blobRefs.Lock()
 	defer c.blobRefs.Unlock()
 
 	debug.Log("checking %d blobs", len(c.blobRefs.M))
-	for id, flags := range c.blobRefs.M {
-		if (flags & blobStatusReferenced) == 0 {
-			debug.Log("blob %v not referenced", id)
-			blobs = append(blobs, id)
+	ctx, cancel := context.WithCancel(ctx)
+	defer cancel()
+
+	for blob := range c.repo.Index().Each(ctx) {
+		h := restic.BlobHandle{ID: blob.ID, Type: blob.Type}
+		if !c.blobRefs.M.Has(h) {
+			debug.Log("blob %v not referenced", h)
+			blobs = append(blobs, h)
 		}
 	}
 

internal/checker/checker_test.go

@@ -181,7 +181,7 @@ func TestUnreferencedBlobs(t *testing.T) {
 	test.OKs(t, checkPacks(chkr))
 	test.OKs(t, checkStruct(chkr))
 
-	blobs := chkr.UnusedBlobs()
+	blobs := chkr.UnusedBlobs(context.TODO())
 	sort.Sort(blobs)
 
 	test.Equals(t, unusedBlobsBySnapshot, blobs)

internal/checker/testing.go

@@ -37,7 +37,7 @@ func TestCheckRepo(t testing.TB, repo restic.Repository) {
 	}
 
 	// unused blobs
-	blobs := chkr.UnusedBlobs()
+	blobs := chkr.UnusedBlobs(context.TODO())
 	if len(blobs) > 0 {
 		t.Errorf("unused blobs found: %v", blobs)
 	}