/
script.go
112 lines (104 loc) · 2.64 KB
/
script.go
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// Copyright 2014 Arne Roomann-Kurrik
//
// Licensed 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 twodee
import (
"errors"
"fmt"
"github.com/robertkrimen/otto"
)
type Scripting struct {
vm *otto.Otto
listeners map[string][]otto.Value
}
func NewScripting() (s *Scripting, err error) {
s = &Scripting{
vm: otto.New(),
listeners: map[string][]otto.Value{},
}
return
}
func (s *Scripting) setAPI() {
var err = errors.New("Usage: addEventListener(string, func)")
s.vm.Set("addEventListener", func(call otto.FunctionCall) otto.Value {
if len(call.ArgumentList) != 2 {
panic(err)
}
if !call.Argument(0).IsString() {
panic(err)
}
if !call.Argument(1).IsFunction() {
panic(err)
}
var (
callbacks []otto.Value
present bool
eventName = call.Argument(0).String()
)
if callbacks, present = s.listeners[eventName]; !present {
s.listeners[eventName] = callbacks
}
s.listeners[eventName] = append(s.listeners[eventName], call.Argument(1))
return otto.Value{}
})
}
func (s *Scripting) LoadScript(path string) (err error) {
var (
script *otto.Script
)
if script, err = s.vm.Compile(path, nil); err != nil {
return
}
s.setAPI()
if _, err = s.vm.Run(script); err != nil {
return
}
return
}
func (s *Scripting) convertArguments(args []interface{}) (converted []interface{}, err error) {
var (
i int
arg interface{}
)
converted = make([]interface{}, len(args))
for i, arg = range args {
if converted[i], err = s.vm.ToValue(arg); err != nil {
return
}
}
return
}
func (s *Scripting) TriggerEvent(eventName string, rawArguments ...interface{}) (err error) {
var (
present bool
callbacks []otto.Value
callback otto.Value
response otto.Value
arguments []interface{}
)
if callbacks, present = s.listeners[eventName]; !present {
return // Not an error to have no listeners.
}
if arguments, err = s.convertArguments(rawArguments); err != nil {
return
}
for _, callback = range callbacks {
if response, err = callback.Call(callback, arguments...); err != nil {
return
}
if response.IsString() {
fmt.Printf("Response from callback: %s\n", response.String())
}
}
return
}