mirror of https://github.com/xSmurf/oz.git
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
83 lines
2.2 KiB
83 lines
2.2 KiB
10 years ago
|
package ipc
|
||
|
|
import (
|
||
|
|
"reflect"
|
||
|
|
"errors"
|
||
|
|
"fmt"
|
||
|
|
)
|
||
|
|
|
||
|
|
type handlerMap map[string]reflect.Value
|
||
|
|
|
||
|
|
func (handlers handlerMap) dispatch(m *Message) error {
|
||
|
|
h,ok := handlers[m.Type]
|
||
|
|
if !ok {
|
||
|
|
return errors.New("no handler found for message type:"+ m.Type)
|
||
|
|
}
|
||
|
|
return executeHandler(h, m)
|
||
|
|
}
|
||
|
|
|
||
|
|
func executeHandler(h reflect.Value, m *Message) error {
|
||
|
|
var args [2]reflect.Value
|
||
|
|
args[0] = reflect.ValueOf(m.Body)
|
||
|
|
args[1]= reflect.ValueOf(m)
|
||
|
|
|
||
|
|
rs := h.Call(args[:])
|
||
|
|
if len(rs) != 1 {
|
||
|
|
return errors.New("handler function did not return expected single result value")
|
||
|
|
}
|
||
|
|
if rs[0].IsNil() {
|
||
|
|
return nil
|
||
|
|
}
|
||
|
|
return rs[0].Interface().(error)
|
||
|
|
}
|
||
|
|
|
||
|
|
func (handlers handlerMap) addHandler(h interface{}) error {
|
||
|
|
msgType, err := typeCheckHandler(h)
|
||
|
|
if err != nil {
|
||
|
|
return err
|
||
|
|
}
|
||
|
|
if _,ok := handlers[msgType]; ok{
|
||
|
|
return fmt.Errorf("duplicate handler registered for message type '%s'", msgType)
|
||
|
|
}
|
||
|
|
handlers[msgType] = reflect.ValueOf(h)
|
||
|
|
return nil
|
||
|
|
}
|
||
|
|
|
||
|
|
var errType = reflect.TypeOf((*error)(nil)).Elem()
|
||
|
|
var messageType = reflect.TypeOf((*Message)(nil))
|
||
|
|
|
||
|
|
func typeCheckHandler(h interface{}) (string, error) {
|
||
|
|
t := reflect.TypeOf(h)
|
||
|
|
if t.Kind() != reflect.Func {
|
||
|
|
return "", fmt.Errorf("handler %v is not a function", t)
|
||
|
|
}
|
||
|
|
if t.NumIn() != 2 {
|
||
|
|
return "", fmt.Errorf("handler %v has incorrect number of input arguments, got %d", t, t.NumIn())
|
||
|
|
}
|
||
|
|
if t.NumOut() != 1 {
|
||
|
|
return "", fmt.Errorf("handler %v has incorrect number of return values %d", t, t.NumOut())
|
||
|
|
}
|
||
|
|
if t.In(0).Kind() != reflect.Ptr {
|
||
|
|
return "", errors.New("first argument of handler is not a pointer")
|
||
|
|
}
|
||
|
|
in0 := t.In(0).Elem()
|
||
|
|
if in0.Kind() != reflect.Struct {
|
||
|
|
return "", fmt.Errorf("first argument of handler is not a pointer to struct")
|
||
|
|
}
|
||
|
|
if in1 := t.In(1); !in1.AssignableTo(messageType) {
|
||
|
|
return "", fmt.Errorf("second argument of handler must have type *Message")
|
||
|
|
}
|
||
|
|
if out := t.Out(0); !out.AssignableTo(errType) {
|
||
|
|
return "", fmt.Errorf("return type of handler must be error")
|
||
|
|
}
|
||
|
|
|
||
|
|
if in0.NumField() == 0 {
|
||
|
|
return "", fmt.Errorf("first argument structure has no fields")
|
||
|
|
}
|
||
|
|
if len(in0.Field(0).Tag) == 0 {
|
||
|
|
return "", fmt.Errorf("first argument structure, first field has no tag")
|
||
|
|
}
|
||
|
|
return string(in0.Field(0).Tag), nil
|
||
|
|
}
|
||
|
|
|
||
|
|
|