Add: context value

context/context.go

+/*
+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 gxcontext
+
+import (
+	"context"
+)
+
+var (
+	defaultCtxKey = 1
+)
+
+type Values struct {
+	m map[interface{}]interface{}
+}
+
+func (v Values) Get(key interface{}) (interface{}, bool) {
+	i, b := v.m[key]
+	return i, b
+}
+
+func (c Values) Set(key interface{}, value interface{}) {
+	c.m[key] = value
+}
+
+func (c Values) Delete(key interface{}) {
+	delete(c.m, key)
+}
+
+type ValuesContext struct {
+	context.Context
+}
+
+func NewValuesContext(ctx context.Context) *ValuesContext {
+	if ctx == nil {
+		ctx = context.Background()
+	}
+
+	return &ValuesContext{
+		Context: context.WithValue(
+			ctx,
+			defaultCtxKey,
+			Values{m: make(map[interface{}]interface{}, 4)},
+		),
+	}
+}
+
+func (c *ValuesContext) Get(key interface{}) (interface{}, bool) {
+	return c.Context.Value(defaultCtxKey).(Values).Get(key)
+}
+
+func (c *ValuesContext) Delete(key interface{}) {
+	c.Context.Value(defaultCtxKey).(Values).Delete(key)
+}
+
+func (c *ValuesContext) Set(key interface{}, value interface{}) {
+	c.Context.Value(defaultCtxKey).(Values).Set(key, value)
+}

context/context_test.go

+package gxcontext
+
+import (
+	"testing"
+)
+
+import (
+	"github.com/stretchr/testify/assert"
+)
+
+func TestValuesContext_General(t *testing.T) {
+	vc := NewValuesContext(nil)
+	assert.NotNil(t, vc)
+
+	key := "hello"
+	value := "world"
+	v, ok := vc.Get(key)
+	assert.Nil(t, v)
+	assert.False(t, ok)
+
+	vc.Set(key, value)
+	v, ok = vc.Get(key)
+	assert.Equal(t, v.(string), value)
+	assert.True(t, ok)
+}