Isolate locale-handling functions from i18n interface

This changes allows to make a clean i18n package (without dependency on
a specific implementation of the translation package) that, in turn,
allows to export packages that internally use i18n with the minimal
dependency load.

Author: cmaglie

commands/instances.go

@@ -38,6 +38,7 @@ import (
 	"github.com/arduino/arduino-cli/internal/arduino/sketch"
 	"github.com/arduino/arduino-cli/internal/arduino/utils"
 	"github.com/arduino/arduino-cli/internal/i18n"
+	"github.com/arduino/arduino-cli/internal/locales"
 	rpc "github.com/arduino/arduino-cli/rpc/cc/arduino/cli/commands/v1"
 	paths "github.com/arduino/go-paths-helper"
 	"github.com/sirupsen/logrus"
@@ -420,7 +421,7 @@ func (s *arduinoCoreServerImpl) Init(req *rpc.InitRequest, stream rpc.ArduinoCor
 	// language of the CLI if the locale is different
 	// after started.
 	if locale, ok, _ := s.settings.GetStringOk("locale"); ok {
-		i18n.Init(locale)
+		locales.Init(locale)
 	}
 
 	return nil

internal/i18n/i18n.go

@@ -15,31 +15,28 @@
 
 package i18n
 
-// Init initializes the i18n module, setting the locale according to this order of preference:
-// 1. Locale specified via the function call
-// 2. OS Locale
-// 3. en (default)
-func Init(configLocale string) {
-	locales := supportedLocales()
-	if configLocale != "" {
-		if locale := findMatchingLocale(configLocale, locales); locale != "" {
-			setLocale(locale)
-			return
-		}
-	}
-
-	if osLocale := getLocaleIdentifierFromOS(); osLocale != "" {
-		if locale := findMatchingLocale(osLocale, locales); locale != "" {
-			setLocale(locale)
-			return
-		}
-	}
-
-	setLocale("en")
+import "fmt"
+
+type Locale interface {
+	Get(msg string, args ...interface{}) string
+}
+
+type nullLocale struct{}
+
+func (n nullLocale) Parse([]byte) {}
+
+func (n nullLocale) Get(msg string, args ...interface{}) string {
+	return fmt.Sprintf(msg, args...)
+}
+
+var locale Locale = &nullLocale{}
+
+func SetLocale(l Locale) {
+	locale = l
 }
 
 // Tr returns msg translated to the selected locale
 // the msg argument must be a literal string
 func Tr(msg string, args ...interface{}) string {
-	return po.Get(msg, args...)
+	return locale.Get(msg, args...)
 }

internal/i18n/i18n_test.go

@@ -25,8 +25,9 @@ import (
 )
 
 func setPo(poFile string) {
-	po = gotext.NewPo()
-	po.Parse([]byte(poFile))
+	dict := gotext.NewPo()
+	dict.Parse([]byte(poFile))
+	SetLocale(dict)
 }
 
 func TestPoTranslation(t *testing.T) {
@@ -39,7 +40,7 @@ func TestPoTranslation(t *testing.T) {
 }
 
 func TestNoLocaleSet(t *testing.T) {
-	po = gotext.NewPo()
+	locale = gotext.NewPo()
 	require.Equal(t, "test-key", Tr("test-key"))
 }
 

internal/i18n/README.md renamed to internal/locales/README.md

@@ -24,7 +24,7 @@ import (
 	"path/filepath"
 	"strconv"
 
-	"github.com/arduino/arduino-cli/internal/i18n/cmd/po"
+	"github.com/arduino/arduino-cli/internal/locales/cmd/po"
 )
 
 // GenerateCatalog generates the i18n message catalog for the go source files

internal/i18n/cmd/ast/parser.go renamed to internal/locales/cmd/ast/parser.go

@@ -19,7 +19,7 @@ import (
 	"os"
 	"path/filepath"
 
-	"github.com/arduino/arduino-cli/internal/i18n/cmd/ast"
+	"github.com/arduino/arduino-cli/internal/locales/cmd/ast"
 	"github.com/spf13/cobra"
 )
 

internal/i18n/cmd/commands/catalog/catalog.go renamed to internal/locales/cmd/commands/catalog/catalog.go

@@ -16,8 +16,8 @@
 package commands
 
 import (
-	"github.com/arduino/arduino-cli/internal/i18n/cmd/commands/catalog"
-	"github.com/arduino/arduino-cli/internal/i18n/cmd/commands/transifex"
+	"github.com/arduino/arduino-cli/internal/locales/cmd/commands/catalog"
+	"github.com/arduino/arduino-cli/internal/locales/cmd/commands/transifex"
 	"github.com/spf13/cobra"
 )