From fbe99c65ec36bb0d8b3a508e0894a9830ff9c995 Mon Sep 17 00:00:00 2001
From: bodqhrohro <bodqhrohro@gmail.com>
Date: Mon, 11 Nov 2019 01:50:50 +0200
Subject: Implementation of Ruby YAML::Store and read/save of the session
 database

---
 yamldb/yamldb.go | 47 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 47 insertions(+)
 create mode 100644 yamldb/yamldb.go

(limited to 'yamldb')

diff --git a/yamldb/yamldb.go b/yamldb/yamldb.go
new file mode 100644
index 0000000..eec23be
--- /dev/null
+++ b/yamldb/yamldb.go
@@ -0,0 +1,47 @@
+package yamldb
+
+import (
+	"github.com/pkg/errors"
+	"io/ioutil"
+	"os"
+	"sync"
+
+	log "github.com/sirupsen/logrus"
+)
+
+// YamlDB represents a YAML file database instance
+type YamlDB struct {
+	Path    string
+	PathNew string
+	lock    sync.Mutex
+}
+
+// Transaction executes the given callback and safely saves
+// the data after they are modified within the callback
+func (db *YamlDB) Transaction(callback func(), marshaller func() ([]byte, error)) error {
+	var err error
+
+	log.Debug("Enter transaction")
+	db.lock.Lock()
+	defer func() {
+		db.lock.Unlock()
+		log.Debug("Exit transaction")
+	}()
+
+	callback()
+
+	yamlData, err := marshaller()
+	if err != nil {
+		return errors.Wrap(err, "Data marshalling error")
+	}
+	err = ioutil.WriteFile(db.PathNew, yamlData, 0644)
+	if err != nil {
+		return errors.Wrap(err, "YamlDB write failure")
+	}
+	err = os.Rename(db.PathNew, db.Path)
+	if err != nil {
+		return errors.Wrap(err, "Couldn't rewrite an old YamlDB file")
+	}
+
+	return nil
+}
-- 
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