add setSubEnv and getSubEnv

Docker-DCO-1.1-Signed-off-by: Victor Vieux <victor.vieux@docker.com> (github: vieux)

engine/env.go

@@ -86,6 +86,28 @@ func (env *Env) GetList(key string) []string {
 	return l
 }
 
+func (env *Env) GetSubEnv(key string) *Env {
+	sval := env.Get(key)
+	if sval == "" {
+		return nil
+	}
+	buf := bytes.NewBufferString(sval)
+	var sub Env
+	if err := sub.Decode(buf); err != nil {
+		return nil
+	}
+	return &sub
+}
+
+func (env *Env) SetSubEnv(key string, sub *Env) error {
+	var buf bytes.Buffer
+	if err := sub.Encode(&buf); err != nil {
+		return err
+	}
+	env.Set(key, string(buf.Bytes()))
+	return nil
+}
+
 func (env *Env) GetJson(key string, iface interface{}) error {
 	sval := env.Get(key)
 	if sval == "" {

engine/job.go

@@ -118,6 +118,14 @@ func (job *Job) SetenvBool(key string, value bool) {
 	job.env.SetBool(key, value)
 }
 
+func (job *Job) GetenvSubEnv(key string) *Env {
+	return job.env.GetSubEnv(key)
+}
+
+func (job *Job) SetenvSubEnv(key string, value *Env) error {
+	return job.env.SetSubEnv(key, value)
+}
+
 func (job *Job) GetenvInt64(key string) int64 {
 	return job.env.GetInt64(key)
 }