From ad8125d83c96d5437ea656ad986f94f1cf944319 Mon Sep 17 00:00:00 2001
From: Alexander Neumann <alexander@bumpern.de>
Date: Mon, 4 Aug 2014 23:25:58 +0200
Subject: [PATCH] Add command 'fsck'

---
 cmd/khepri/cmd_fsck.go | 86 ++++++++++++++++++++++++++++++++++++++++++
 cmd/khepri/main.go     |  1 +
 snapshot.go            |  2 +
 3 files changed, 89 insertions(+)
 create mode 100644 cmd/khepri/cmd_fsck.go

diff --git a/cmd/khepri/cmd_fsck.go b/cmd/khepri/cmd_fsck.go
new file mode 100644
index 000000000..f85a380c5
--- /dev/null
+++ b/cmd/khepri/cmd_fsck.go
@@ -0,0 +1,86 @@
+package main
+
+import (
+	"crypto/sha256"
+	"encoding/json"
+	"log"
+
+	"github.com/fd0/khepri"
+)
+
+func fsck_tree(repo *khepri.Repository, id khepri.ID) (bool, error) {
+	log.Printf("  checking dir %s", id)
+
+	rd, err := repo.Get(khepri.TYPE_BLOB, id)
+	if err != nil {
+		return false, err
+	}
+
+	hr := khepri.NewHashingReader(rd, sha256.New)
+	dec := json.NewDecoder(hr)
+
+	tree := &khepri.Tree{}
+	err = dec.Decode(tree)
+
+	if err != nil {
+		return false, err
+	}
+
+	if !id.Equal(hr.Hash()) {
+		return false, nil
+	}
+
+	return true, nil
+}
+
+func fsck_snapshot(repo *khepri.Repository, id khepri.ID) (bool, error) {
+	log.Printf("checking snapshot %s", id)
+
+	sn, err := khepri.LoadSnapshot(repo, id)
+	if err != nil {
+		return false, err
+	}
+
+	return fsck_tree(repo, sn.TreeID)
+}
+
+func commandFsck(repo *khepri.Repository, args []string) error {
+	var snapshots khepri.IDs
+	var err error
+
+	if len(args) != 0 {
+		snapshots = make(khepri.IDs, 0, len(args))
+
+		for _, arg := range args {
+			id, err := khepri.ParseID(arg)
+			if err != nil {
+				log.Fatal(err)
+			}
+
+			snapshots = append(snapshots, id)
+		}
+	} else {
+		snapshots, err = repo.List(khepri.TYPE_REF)
+
+		if err != nil {
+			log.Fatalf("error reading list of snapshot IDs: %v", err)
+		}
+	}
+
+	log.Printf("checking %d snapshots", len(snapshots))
+
+	for _, id := range snapshots {
+		ok, err := fsck_snapshot(repo, id)
+
+		if err != nil {
+			log.Printf("error checking snapshot %s: %v", id, err)
+			continue
+		}
+
+		if !ok {
+			log.Printf("snapshot %s failed", id)
+		}
+	}
+
+	return nil
+}
diff --git a/cmd/khepri/main.go b/cmd/khepri/main.go
index 7aeac74f4..6288b317b 100644
--- a/cmd/khepri/main.go
+++ b/cmd/khepri/main.go
@@ -32,6 +32,7 @@ func init() {
 	commands["restore"] = commandRestore
 	commands["list"] = commandList
 	commands["snapshots"] = commandSnapshots
+	commands["fsck"] = commandFsck
 }
 
 func main() {
diff --git a/snapshot.go b/snapshot.go
index 555ebcf1e..c35bdcda7 100644
--- a/snapshot.go
+++ b/snapshot.go
@@ -68,6 +68,8 @@ func LoadSnapshot(repo *Repository, id ID) (*Snapshot, error) {
 		return nil, err
 	}
 
+	// TODO: maybe inject a hashing reader here and test if the given id is correct
+
 	dec := json.NewDecoder(rd)
 	sn := &Snapshot{}
 	err = dec.Decode(sn)