From ff9a014afc1c53f3cae0093a642c8f7c99271c12 Mon Sep 17 00:00:00 2001
From: Alex Yatskov <alex@foosoft.net>
Date: Wed, 17 Jun 2015 16:50:07 +0900
Subject: [PATCH] Improvements to metadata

---
 meta.go    | 16 ++++++++++++++++
 node.go    |  2 +-
 version.go |  4 ----
 3 files changed, 17 insertions(+), 5 deletions(-)

diff --git a/meta.go b/meta.go
index 76a0fcb..24fbf42 100644
--- a/meta.go
+++ b/meta.go
@@ -36,6 +36,7 @@ import (
 type versionMetadata struct {
 	Deleted []string `json:"deleted"`
 	path    string
+	dirty   bool
 }
 
 func newVersionMetadata(path string) (*versionMetadata, error) {
@@ -57,7 +58,18 @@ func (this *versionMetadata) filter(nodes versionedNodeMap) {
 	}
 }
 
+func (this *versionMetadata) destroyPath(path string) {
+	this.Deleted = append(this.Deleted, path)
+	this.dirty = true
+}
+
+func (this *versionMetadata) createPath(path string) {
+	this.dirty = true
+}
+
 func (this *versionMetadata) load() error {
+	this.dirty = false
+
 	if _, err := os.Stat(this.path); os.IsNotExist(err) {
 		return nil
 	}
@@ -75,6 +87,10 @@ func (this *versionMetadata) load() error {
 }
 
 func (this *versionMetadata) save() error {
+	if !this.dirty {
+		return nil
+	}
+
 	js, err := json.Marshal(this)
 	if err != nil {
 		return err
diff --git a/node.go b/node.go
index e77a15d..e2806fa 100644
--- a/node.go
+++ b/node.go
@@ -102,7 +102,7 @@ func (this *versionedNode) remove() error {
 		ver = ver.parent
 	}
 
-	ver.removePath(this.path)
+	ver.meta.destroyPath(this.path)
 	return nil
 }
 
diff --git a/version.go b/version.go
index b034e8a..35eb769 100644
--- a/version.go
+++ b/version.go
@@ -145,10 +145,6 @@ func (this *version) rebasePath(paths ...string) string {
 	return filepath.Join(combined...)
 }
 
-func (this *version) removePath(path string) {
-	this.meta.Deleted = append(this.meta.Deleted, path)
-}
-
 func (this *version) finalize() error {
 	return this.meta.save()
 }