THRIFT-3160 go: make generated enum types implement TextMarshaler and…

… TextUnmarshaler

Client: Go
Patch: Konstantin Shaposhnikov <k.shaposhnikov@gmail.com>

This closes #507

compiler/cpp/src/generate/t_go_generator.cc

@@ -923,6 +923,19 @@ void t_go_generator::generate_enum(t_enum* tenum) {
   // type.
   f_types_ << "func " << tenum_name << "Ptr(v " << tenum_name << ") *" << tenum_name
            << " { return &v }" << endl << endl;
+
+  // Generate MarshalText
+  f_types_ << "func (p " << tenum_name << ") MarshalText() ([]byte, error) {" << endl;
+  f_types_ << "return []byte(p.String()), nil" << endl;
+  f_types_ << "}" << endl << endl;
+
+  // Generate UnmarshalText
+  f_types_ << "func (p *" << tenum_name << ") UnmarshalText(text []byte) error {" << endl;
+  f_types_ << "q, err := " << tenum_name << "FromString(string(text))" << endl;
+  f_types_ << "if (err != nil) {" << endl << "return err" << endl << "}" << endl;
+  f_types_ << "*p = q" << endl;
+  f_types_ << "return nil" << endl;
+  f_types_ << "}" << endl;
 }
 
 /**

lib/go/test/tests/encoding_json_test.go

@@ -0,0 +1,79 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied. See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package tests
+
+import (
+	"encoding"
+	"encoding/json"
+	"testing"
+	"thrifttest"
+)
+
+func TestEnumIsTextMarshaller(t *testing.T) {
+	one := thrifttest.Numberz_ONE
+	var tm encoding.TextMarshaler = one
+	b, err := tm.MarshalText()
+	if err != nil {
+		t.Fatalf("Unexpected error from MarshalText: %s", err)
+	}
+	if string(b) != one.String() {
+		t.Errorf("MarshalText(%s) = %s, expected = %s", one, b, one)
+	}
+}
+
+func TestEnumIsTextUnmarshaller(t *testing.T) {
+	var tm encoding.TextUnmarshaler = thrifttest.NumberzPtr(thrifttest.Numberz_TWO)
+	err := tm.UnmarshalText([]byte("TWO"))
+	if err != nil {
+		t.Fatalf("Unexpected error from UnmarshalText(TWO): %s", err)
+	}
+	if *(tm.(*thrifttest.Numberz)) != thrifttest.Numberz_TWO {
+		t.Errorf("UnmarshalText(TWO) = %s", tm)
+	}
+
+	err = tm.UnmarshalText([]byte("NAN"))
+	if err == nil {
+		t.Errorf("Error from UnmarshalText(NAN)")
+	}
+}
+
+func TestJSONMarshalUnmarshal(t *testing.T) {
+	s1 := thrifttest.StructB{
+		Aa: &thrifttest.StructA{S: "Aa"},
+		Ab: &thrifttest.StructA{S: "Ab"},
+	}
+
+	b, err := json.Marshal(s1)
+	if err != nil {
+		t.Fatalf("Unexpected error from json.Marshal: %s", err)
+	}
+
+	s2 := thrifttest.StructB{}
+	err = json.Unmarshal(b, &s2)
+	if err != nil {
+		t.Fatalf("Unexpected error from json.Unmarshal: %s", err)
+	}
+
+	if *s1.Aa != *s2.Aa || *s1.Ab != *s2.Ab {
+		t.Logf("s1 = %+v", s1)
+		t.Logf("s2 = %+v", s2)
+		t.Errorf("json: Unmarshal(Marshal(s)) != s")
+	}
+}