restorer: extract hardlinks index from restic package

internal/restorer/hardlinks_index.go

@@ -0,0 +1,57 @@
+package restorer
+
+import (
+	"sync"
+)
+
+// HardlinkKey is a composed key for finding inodes on a specific device.
+type HardlinkKey struct {
+	Inode, Device uint64
+}
+
+// HardlinkIndex contains a list of inodes, devices these inodes are one, and associated file names.
+type HardlinkIndex struct {
+	m     sync.Mutex
+	Index map[HardlinkKey]string
+}
+
+// NewHardlinkIndex create a new index for hard links
+func NewHardlinkIndex() *HardlinkIndex {
+	return &HardlinkIndex{
+		Index: make(map[HardlinkKey]string),
+	}
+}
+
+// Has checks wether the link already exist in the index.
+func (idx *HardlinkIndex) Has(inode uint64, device uint64) bool {
+	idx.m.Lock()
+	defer idx.m.Unlock()
+	_, ok := idx.Index[HardlinkKey{inode, device}]
+
+	return ok
+}
+
+// Add adds a link to the index.
+func (idx *HardlinkIndex) Add(inode uint64, device uint64, name string) {
+	idx.m.Lock()
+	defer idx.m.Unlock()
+	_, ok := idx.Index[HardlinkKey{inode, device}]
+
+	if !ok {
+		idx.Index[HardlinkKey{inode, device}] = name
+	}
+}
+
+// GetFilename obtains the filename from the index.
+func (idx *HardlinkIndex) GetFilename(inode uint64, device uint64) string {
+	idx.m.Lock()
+	defer idx.m.Unlock()
+	return idx.Index[HardlinkKey{inode, device}]
+}
+
+// Remove removes a link from the index.
+func (idx *HardlinkIndex) Remove(inode uint64, device uint64) {
+	idx.m.Lock()
+	defer idx.m.Unlock()
+	delete(idx.Index, HardlinkKey{inode, device})
+}

internal/restorer/hardlinks_index_test.go

@@ -0,0 +1,33 @@
+package restorer_test
+
+import (
+	"testing"
+
+	"github.com/restic/restic/internal/restorer"
+	rtest "github.com/restic/restic/internal/test"
+)
+
+// TestHardLinks contains various tests for HardlinkIndex.
+func TestHardLinks(t *testing.T) {
+
+	idx := restorer.NewHardlinkIndex()
+
+	idx.Add(1, 2, "inode1-file1-on-device2")
+	idx.Add(2, 3, "inode2-file2-on-device3")
+
+	sresult := idx.GetFilename(1, 2)
+	rtest.Equals(t, sresult, "inode1-file1-on-device2")
+
+	sresult = idx.GetFilename(2, 3)
+	rtest.Equals(t, sresult, "inode2-file2-on-device3")
+
+	bresult := idx.Has(1, 2)
+	rtest.Equals(t, bresult, true)
+
+	bresult = idx.Has(1, 3)
+	rtest.Equals(t, bresult, false)
+
+	idx.Remove(1, 2)
+	bresult = idx.Has(1, 2)
+	rtest.Equals(t, bresult, false)
+}

internal/restorer/restorer.go

@@ -218,7 +218,7 @@ func (res *Restorer) RestoreTo(ctx context.Context, dst string) error {
 		}
 	}
 
-	idx := restic.NewHardlinkIndex()
+	idx := NewHardlinkIndex()
 	filerestorer := newFileRestorer(dst, res.repo.Backend().Load, res.repo.Key(), res.repo.Index().Lookup, res.repo.Connections())
 	filerestorer.Error = res.Error