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moby--moby/engine/env.go
2013-12-13 16:29:22 -08:00

234 lines
4.9 KiB
Go

package engine
import (
"bytes"
"encoding/json"
"fmt"
"io"
"strconv"
"strings"
)
type Env []string
func (env *Env) Get(key string) (value string) {
// FIXME: use Map()
for _, kv := range *env {
if strings.Index(kv, "=") == -1 {
continue
}
parts := strings.SplitN(kv, "=", 2)
if parts[0] != key {
continue
}
if len(parts) < 2 {
value = ""
} else {
value = parts[1]
}
}
return
}
func (env *Env) Exists(key string) bool {
_, exists := env.Map()[key]
return exists
}
func (env *Env) GetBool(key string) (value bool) {
s := strings.ToLower(strings.Trim(env.Get(key), " \t"))
if s == "" || s == "0" || s == "no" || s == "false" || s == "none" {
return false
}
return true
}
func (env *Env) SetBool(key string, value bool) {
if value {
env.Set(key, "1")
} else {
env.Set(key, "0")
}
}
func (env *Env) GetInt(key string) int {
return int(env.GetInt64(key))
}
func (env *Env) GetInt64(key string) int64 {
s := strings.Trim(env.Get(key), " \t")
val, err := strconv.ParseInt(s, 10, 64)
if err != nil {
return -1
}
return val
}
func (env *Env) SetInt(key string, value int) {
env.Set(key, fmt.Sprintf("%d", value))
}
func (env *Env) SetInt64(key string, value int64) {
env.Set(key, fmt.Sprintf("%d", value))
}
// Returns nil if key not found
func (env *Env) GetList(key string) []string {
sval := env.Get(key)
if sval == "" {
return nil
}
l := make([]string, 0, 1)
if err := json.Unmarshal([]byte(sval), &l); err != nil {
l = append(l, sval)
}
return l
}
func (env *Env) GetJson(key string, iface interface{}) error {
sval := env.Get(key)
if sval == "" {
return nil
}
return json.Unmarshal([]byte(sval), iface)
}
func (env *Env) SetJson(key string, value interface{}) error {
sval, err := json.Marshal(value)
if err != nil {
return err
}
env.Set(key, string(sval))
return nil
}
func (env *Env) SetList(key string, value []string) error {
return env.SetJson(key, value)
}
func (env *Env) Set(key, value string) {
*env = append(*env, key+"="+value)
}
func NewDecoder(src io.Reader) *Decoder {
return &Decoder{
json.NewDecoder(src),
}
}
type Decoder struct {
*json.Decoder
}
func (decoder *Decoder) Decode() (*Env, error) {
m := make(map[string]interface{})
if err := decoder.Decoder.Decode(&m); err != nil {
return nil, err
}
env := &Env{}
for key, value := range m {
env.SetAuto(key, value)
}
return env, nil
}
// DecodeEnv decodes `src` as a json dictionary, and adds
// each decoded key-value pair to the environment.
//
// If `src` cannot be decoded as a json dictionary, an error
// is returned.
func (env *Env) Decode(src io.Reader) error {
m := make(map[string]interface{})
if err := json.NewDecoder(src).Decode(&m); err != nil {
return err
}
for k, v := range m {
env.SetAuto(k, v)
}
return nil
}
func (env *Env) SetAuto(k string, v interface{}) {
// FIXME: we fix-convert float values to int, because
// encoding/json decodes integers to float64, but cannot encode them back.
// (See http://golang.org/src/pkg/encoding/json/decode.go#L46)
if fval, ok := v.(float64); ok {
env.SetInt64(k, int64(fval))
} else if sval, ok := v.(string); ok {
env.Set(k, sval)
} else if val, err := json.Marshal(v); err == nil {
env.Set(k, string(val))
} else {
env.Set(k, fmt.Sprintf("%v", v))
}
}
func (env *Env) Encode(dst io.Writer) error {
m := make(map[string]interface{})
for k, v := range env.Map() {
var val interface{}
if err := json.Unmarshal([]byte(v), &val); err == nil {
// FIXME: we fix-convert float values to int, because
// encoding/json decodes integers to float64, but cannot encode them back.
// (See http://golang.org/src/pkg/encoding/json/decode.go#L46)
if fval, isFloat := val.(float64); isFloat {
val = int(fval)
}
m[k] = val
} else {
m[k] = v
}
}
if err := json.NewEncoder(dst).Encode(&m); err != nil {
return err
}
return nil
}
func (env *Env) WriteTo(dst io.Writer) (n int64, err error) {
// FIXME: return the number of bytes written to respect io.WriterTo
return 0, env.Encode(dst)
}
func (env *Env) Export(dst interface{}) (err error) {
defer func() {
if err != nil {
err = fmt.Errorf("ExportEnv %s", err)
}
}()
var buf bytes.Buffer
// step 1: encode/marshal the env to an intermediary json representation
if err := env.Encode(&buf); err != nil {
return err
}
// step 2: decode/unmarshal the intermediary json into the destination object
if err := json.NewDecoder(&buf).Decode(dst); err != nil {
return err
}
return nil
}
func (env *Env) Import(src interface{}) (err error) {
defer func() {
if err != nil {
err = fmt.Errorf("ImportEnv: %s", err)
}
}()
var buf bytes.Buffer
if err := json.NewEncoder(&buf).Encode(src); err != nil {
return err
}
if err := env.Decode(&buf); err != nil {
return err
}
return nil
}
func (env *Env) Map() map[string]string {
m := make(map[string]string)
for _, kv := range *env {
parts := strings.SplitN(kv, "=", 2)
m[parts[0]] = parts[1]
}
return m
}