add charset support for fields

Summary: Basically, adding support for Hebrew characters.

Reviewed By: alexsn

Differential Revision: D16068537

fbshipit-source-id: 4e934da5ea97c9e804317f746556ab1d51faebcc

field/field.go

@@ -77,6 +77,7 @@ type Field struct {
 	tag        string
 	name       string
 	comment    string
+	charset    string
 	unique     bool
 	nullable   bool
 	optional   bool
@@ -383,6 +384,16 @@ func (b *stringBuilder) StructTag(s string) *stringBuilder {
 	return b
 }
 
+// SetCharset sets the character set attribute for character fields.
+// For example, utf8 or utf8mb4 in MySQL.
+func (b *stringBuilder) SetCharset(s string) *stringBuilder {
+	b.charset = s
+	return b
+}
+
+// Charset returns the character set of the field.
+func (b stringBuilder) Charset() string { return b.charset }
+
 // timeBuilder is the builder for time fields.
 type timeBuilder struct {
 	Field
@@ -450,3 +461,8 @@ func (b *boolBuilder) StructTag(s string) *boolBuilder {
 	b.tag = s
 	return b
 }
+
+// Charseter is the interface that wraps the Charset method.
+type Charseter interface {
+	Charset() string
+}

field/field_test.go

@@ -1,11 +1,12 @@
 package field_test
 
 import (
-	"fbc/ent/field"
-	"github.com/stretchr/testify/require"
 	"regexp"
 	"testing"
 
+	"fbc/ent"
+	"fbc/ent/field"
+
 	"github.com/stretchr/testify/assert"
 )
 
@@ -53,6 +54,13 @@ func TestString(t *testing.T) {
 	assert.Len(t, f.Validators(), 2)
 }
 
+func TestCharset(t *testing.T) {
+	var f ent.Field = field.String("name").SetCharset("utf8")
+	cs, ok := f.(field.Charseter)
+	assert.True(t, ok, "string field implements the Charseter interface")
+	assert.Equal(t, "utf8", cs.Charset())
+}
+
 func TestTime(t *testing.T) {
 	f := field.Time("created_at")
 	assert.Equal(t, "created_at", f.Name())
@@ -62,5 +70,5 @@ func TestTime(t *testing.T) {
 
 func TestField_Tag(t *testing.T) {
 	f := field.Bool("expired").StructTag(`json:"expired,omitempty"`)
-	require.Equal(t, `json:"expired,omitempty"`, f.Tag())
+	assert.Equal(t, `json:"expired,omitempty"`, f.Tag())
 }