1 files changed, 134 insertions, 0 deletions
diff --git a/backup/restore.go b/backup/restore.go
new file mode 100644
index 0000000..6a03200
--- /dev/null
+++ b/backup/restore.go
@@ -0,0 +1,134 @@
+package backup
+
+import (
+	"code.laria.me/petrific/acl"
+	"code.laria.me/petrific/fs"
+	"code.laria.me/petrific/objects"
+	"code.laria.me/petrific/storage"
+	"fmt"
+	"io"
+	"os"
+)
+
+func RestoreFile(s storage.Storage, id objects.ObjectId, w io.Writer) error {
+	file, err := storage.GetObjectOfType(s, id, objects.OTFile)
+	if err != nil {
+		return err
+	}
+
+	for i, fragment := range *file.(*objects.File) {
+		blob_obj, err := storage.GetObjectOfType(s, fragment.Blob, objects.OTBlob)
+		if err != nil {
+			return err
+		}
+		blob := *blob_obj.(*objects.Blob)
+
+		if uint64(len(blob)) != fragment.Size {
+			return fmt.Errorf("RestoreFile: blob size of %s doesn't match size in fragment %d of file %s", fragment.Blob, i, id)
+		}
+
+		if _, err := w.Write(blob); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+func execBitFromACL(a acl.ACL) bool {
+	return a.ToUnixPerms()&0100 != 0
+}
+
+func RestoreDir(s storage.Storage, id objects.ObjectId, root fs.Dir) error {
+	tree_obj, err := storage.GetObjectOfType(s, id, objects.OTTree)
+	tree := tree_obj.(objects.Tree)
+
+	seen := make(map[string]struct{})
+
+	for name, file_info := range tree {
+		switch file_info.Type() {
+		case objects.TETFile:
+			tmpname := fmt.Sprintf(".petrific-%d-%s", os.Getpid(), id)
+			new_file, err := root.CreateChildFile(tmpname, execBitFromACL(file_info.ACL()))
+			if err != nil {
+				return err
+			}
+			rwc, err := new_file.Open()
+			if err != nil {
+				return err
+			}
+
+			if err := RestoreFile(s, file_info.(objects.TreeEntryFile).Ref, rwc); err != nil {
+				rwc.Close()
+				return err
+			}
+			rwc.Close()
+
+			if err := root.RenameChild(tmpname, name); err != nil {
+				return err
+			}
+		case objects.TETDir:
+			var subdir fs.Dir
+
+			// Try to use existing directory
+			child, err := root.GetChild(name)
+			if err == nil {
+				if child.Type() == fs.FDir {
+					subdir = child.(fs.Dir)
+				} else {
+					if err := child.Delete(); err != nil {
+						return err
+					}
+				}
+			} else if err != os.ErrNotExist {
+				return err
+			}
+
+			// Create directory, if it doesn't exist
+			if subdir == nil {
+				subdir, err = root.CreateChildDir(name)
+				if err != nil {
+					return err
+				}
+			}
+
+			if err := RestoreDir(s, file_info.(objects.TreeEntryDir).Ref, subdir); err != nil {
+				return err
+			}
+		case objects.TETSymlink:
+			// Is there already a child of that name? If yes, delete it
+			child, err := root.GetChild(name)
+			if err == nil {
+				if err := child.Delete(); err != nil {
+					return err
+				}
+			} else if err != os.ErrNotExist {
+				return err
+			}
+
+			if _, err := root.CreateChildSymlink(name, file_info.(objects.TreeEntrySymlink).Target); err != nil {
+				return err
+			}
+		default:
+			return fmt.Errorf("child '%s' of %s has unknown tree entry type %s", name, id, file_info.Type())
+		}
+
+		seen[name] = struct{}{}
+	}
+
+	// We now restored all children, we now need to remove the children of root, that shouldn't be there accoring to the backup
+	children, err := root.Readdir()
+	if err != nil {
+		return err
+	}
+	for _, c := range children {
+		_, ok := seen[c.Name()]
+		if !ok {
+			if err := c.Delete(); err != nil {
+				return err
+			}
+		}
+	}
+
+	return nil
+}