Use mattermost v5 module (#1192)

vendor/github.com/mattermost/go-i18n/i18n/translation/plural_translation.go

@@ -0,0 +1,82 @@
+package translation
+
+import (
+	"github.com/mattermost/go-i18n/i18n/language"
+)
+
+type pluralTranslation struct {
+	id        string
+	templates map[language.Plural]*template
+}
+
+func (pt *pluralTranslation) MarshalInterface() interface{} {
+	return map[string]interface{}{
+		"id":          pt.id,
+		"translation": pt.templates,
+	}
+}
+
+func (pt *pluralTranslation) MarshalFlatInterface() interface{} {
+	return pt.templates
+}
+
+func (pt *pluralTranslation) ID() string {
+	return pt.id
+}
+
+func (pt *pluralTranslation) Template(pc language.Plural) *template {
+	return pt.templates[pc]
+}
+
+func (pt *pluralTranslation) UntranslatedCopy() Translation {
+	return &pluralTranslation{pt.id, make(map[language.Plural]*template)}
+}
+
+func (pt *pluralTranslation) Normalize(l *language.Language) Translation {
+	// Delete plural categories that don't belong to this language.
+	for pc := range pt.templates {
+		if _, ok := l.Plurals[pc]; !ok {
+			delete(pt.templates, pc)
+		}
+	}
+	// Create map entries for missing valid categories.
+	for pc := range l.Plurals {
+		if _, ok := pt.templates[pc]; !ok {
+			pt.templates[pc] = mustNewTemplate("")
+		}
+	}
+	return pt
+}
+
+func (pt *pluralTranslation) Backfill(src Translation) Translation {
+	for pc, t := range pt.templates {
+		if (t == nil || t.src == "") && src != nil {
+			pt.templates[pc] = src.Template(language.Other)
+		}
+	}
+	return pt
+}
+
+func (pt *pluralTranslation) Merge(t Translation) Translation {
+	other, ok := t.(*pluralTranslation)
+	if !ok || pt.ID() != t.ID() {
+		return t
+	}
+	for pluralCategory, template := range other.templates {
+		if template != nil && template.src != "" {
+			pt.templates[pluralCategory] = template
+		}
+	}
+	return pt
+}
+
+func (pt *pluralTranslation) Incomplete(l *language.Language) bool {
+	for pc := range l.Plurals {
+		if t := pt.templates[pc]; t == nil || t.src == "" {
+			return true
+		}
+	}
+	return false
+}
+
+var _ = Translation(&pluralTranslation{})