git-lfs/config/environment.go
Taylor Blau 6c60d2b2db config: demote *Environment to interface
In order to support lazily loading the values stored in a user's `.gitconfig`,
we must wait until calling `*config.Configuration.loadGitConfig()` until it is
_absolutely necessary_.

To accomplish this, it was proposed that we introduce a wrapped variant of the
`*Environment` type, only for interacting with the `GitFetcher` that was
capable of supporting such beahvior.

As such, a new implementation of the `Environment` type must be defined. Since
previously there only existed the concrete type `*Environment`, this commit
demotes that down to `*enviornment`, and introduces the interface
`Environment`, which it implements.
2016-08-15 13:17:11 -06:00

86 lines
2.1 KiB
Go

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)
// 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)
}
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) Bool(key string, def bool) (val bool) {
s, _ := e.Fetcher.Get(key)
if len(s) == 0 {
return def
}
switch strings.ToLower(s) {
case "true", "1", "on", "yes", "t":
return true
case "false", "0", "off", "no", "f":
return false
default:
return false
}
}
func (e *environment) Int(key string, def int) (val int) {
s, _ := e.Fetcher.Get(key)
if len(s) == 0 {
return def
}
i, err := strconv.Atoi(s)
if err != nil {
return def
}
return i
}