feat: support pass context to another cod instance

.travis.yml

@@ -2,7 +2,6 @@ language: go
 sudo: required
 
 go:
-  - "1.11"
   - "1.12"
   - master
 

context.go

@@ -400,6 +400,13 @@ func (c *Context) Cod(d *Cod) *Cod {
 	return c.cod
 }
 
+// Pass pass requst to another cod
+func (c *Context) Pass(another *Cod) {
+	// 设置为已commit，避免当前cod继续处理
+	c.Committed = true
+	another.ServeHTTP(c.Response, c.Request)
+}
+
 // NewContext new a context
 func NewContext(resp http.ResponseWriter, req *http.Request) *Context {
 	c := &Context{}

context_test.go

@@ -425,3 +425,23 @@ func TestNewContext(t *testing.T) {
 	assert.Equal(c.Request, req)
 	assert.Equal(c.Response, resp)
 }
+
+func TestContextPass(t *testing.T) {
+	assert := assert.New(t)
+	d := New()
+	another := New()
+	another.GET("/", func(c *Context) error {
+		c.BodyBuffer = bytes.NewBufferString("new data")
+		return nil
+	})
+	req := httptest.NewRequest("GET", "https://aslant.site/", nil)
+	resp := httptest.NewRecorder()
+	d.GET("/", func(c *Context) error {
+		c.Pass(another)
+		c.BodyBuffer = bytes.NewBufferString("original data")
+		return nil
+	})
+	d.ServeHTTP(resp, req)
+	assert.Equal(resp.Code, 200)
+	assert.Equal(resp.Body.String(), "new data")
+}