pkg/beam/data/message.go
Solomon Hykes caca8eec08 beam/data: Message.GetOne() returns the last value set at a key
This is a convenience for callers which are only interested in one value
per key. Similar to how HTTP headers allow multiple keys per value, but
are often used to store and retrieve only one value.

Docker-DCO-1.1-Signed-off-by: Solomon Hykes <solomon@docker.com> (github: shykes)
2014-05-09 17:01:27 -07:00

103 lines
1.8 KiB
Go

package data
import (
"fmt"
"strings"
)
type Message string
func Empty() Message {
return Message(Encode(nil))
}
func Parse(args []string) Message {
data := make(map[string][]string)
for _, word := range args {
if strings.Contains(word, "=") {
kv := strings.SplitN(word, "=", 2)
key := kv[0]
var val string
if len(kv) == 2 {
val = kv[1]
}
data[key] = []string{val}
}
}
return Message(Encode(data))
}
func (m Message) Add(k, v string) Message {
data, err := Decode(string(m))
if err != nil {
return m
}
if values, exists := data[k]; exists {
data[k] = append(values, v)
} else {
data[k] = []string{v}
}
return Message(Encode(data))
}
func (m Message) Set(k string, v ...string) Message {
data, err := Decode(string(m))
if err != nil {
panic(err)
return m
}
data[k] = v
return Message(Encode(data))
}
func (m Message) Del(k string) Message {
data, err := Decode(string(m))
if err != nil {
panic(err)
return m
}
delete(data, k)
return Message(Encode(data))
}
func (m Message) Get(k string) []string {
data, err := Decode(string(m))
if err != nil {
return nil
}
v, exists := data[k]
if !exists {
return nil
}
return v
}
// GetOne returns the last value added at the key k,
// or an empty string if there is no value.
func (m Message) GetOne(k string) string {
var v string
if vals := m.Get(k); len(vals) > 0 {
v = vals[len(vals)-1]
}
return v
}
func (m Message) Pretty() string {
data, err := Decode(string(m))
if err != nil {
return ""
}
entries := make([]string, 0, len(data))
for k, values := range data {
entries = append(entries, fmt.Sprintf("%s=%s", k, strings.Join(values, ",")))
}
return strings.Join(entries, " ")
}
func (m Message) String() string {
return string(m)
}
func (m Message) Bytes() []byte {
return []byte(m)
}