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package config
import (
"strconv"
"strings"
)
// An Environment adds additional behavior to a Fetcher, such a type conversion,
// and default values.
//
// `Environment`s are the primary way to communicate with various configuration
// sources, such as the OS environment variables, the `.gitconfig`, and even
// `map[string]string`s.
type Environment interface {
// Get is shorthand for calling `e.Fetcher.Get(key)`.
Get(key string) (val string, ok bool)
// Get is shorthand for calling `e.Fetcher.GetAll(key)`.
GetAll(key string) (vals []string)
// Bool returns the boolean state associated with a given key, or the
// value "def", if no value was associated.
//
// The "boolean state associated with a given key" is defined as the
// case-insensitive string comparison with the following:
//
// 1) true if...
// "true", "1", "on", "yes", or "t"
// 2) false if...
// "false", "0", "off", "no", "f", or otherwise.
Bool(key string, def bool) (val bool)
// Int returns the int value associated with a given key, or the value
// "def", if no value was associated.
//
// To convert from a the string value attached to a given key,
// `strconv.Atoi(val)` is called. If `Atoi` returned a non-nil error,
// then the value "def" will be returned instead.
//
// Otherwise, if the value was converted `string -> int` successfully,
// then it will be returned wholesale.
Int(key string, def int) (val int)
// All returns a copy of all the key/value pairs for the current
// environment.
All() map[string][]string
}
type environment struct {
// Fetcher is the `environment`'s source of data.
Fetcher Fetcher
}
// EnvironmentOf creates a new `Environment` initialized with the givne
// `Fetcher`, "f".
func EnvironmentOf(f Fetcher) Environment {
return &environment{f}
}
func (e *environment) Get(key string) (val string, ok bool) {
return e.Fetcher.Get(key)
}
func (e *environment) GetAll(key string) []string {
return e.Fetcher.GetAll(key)
}
func (e *environment) Bool(key string, def bool) bool {
s, _ := e.Fetcher.Get(key)
return Bool(s, def)
}
func (e *environment) Int(key string, def int) int {
s, _ := e.Fetcher.Get(key)
return Int(s, def)
}
func (e *environment) All() map[string][]string {
return e.Fetcher.All()
}
// Int returns the int value associated with the given value, or the value
// "def", if the value is blank.
//
// To convert from a the string value attached to a given key,
// `strconv.Atoi(val)` is called. If `Atoi` returned a non-nil error,
// then the value "def" will be returned instead.
//
// Otherwise, if the value was converted `string -> int` successfully,
// then it will be returned wholesale.
func Int(value string, def int) int {
if len(value) == 0 {
return def
}
i, err := strconv.Atoi(value)
if err != nil {
return def
}
return i
}
// Bool returns the boolean state associated with the given value, or the
// value "def", if the value is blank.
//
// The "boolean state associated with a given key" is defined as the
// case-insensitive string comparison with the following:
//
// 1. true if...
// "true", "1", "on", "yes", or "t"
// 2. false if...
// "false", "0", "off", "no", "f", or otherwise.
func Bool(value string, def bool) bool {
if len(value) == 0 {
return def
}
switch strings.ToLower(value) {
case "true", "1", "on", "yes", "t":
return true
case "false", "0", "off", "no", "f":
return false
default:
return false
}
}
|
