doodle/pkg/scripting/vm.go

105 lines
2.1 KiB
Go

package scripting
import (
"fmt"
"git.kirsle.net/apps/doodle/lib/render"
"git.kirsle.net/apps/doodle/pkg/log"
"github.com/robertkrimen/otto"
)
// VM manages a single isolated JavaScript VM.
type VM struct {
Name string
// Globals available to the scripts.
Events *Events
Self interface{}
vm *otto.Otto
// setTimeout and setInterval variables.
timerLastID int // becomes 1 when first timer is set
timers map[int]*Timer
}
// NewVM creates a new JavaScript VM.
func NewVM(name string) *VM {
vm := &VM{
Name: name,
Events: NewEvents(),
vm: otto.New(),
timers: map[int]*Timer{},
}
return vm
}
// Run code in the VM.
func (vm *VM) Run(src interface{}) (otto.Value, error) {
v, err := vm.vm.Run(src)
return v, err
}
// Set a value in the VM.
func (vm *VM) Set(name string, v interface{}) error {
return vm.vm.Set(name, v)
}
// RegisterLevelHooks registers accessors to the level hooks
// and Doodad API for Play Mode.
func (vm *VM) RegisterLevelHooks() error {
bindings := map[string]interface{}{
"log": log.Logger,
"RGBA": render.RGBA,
"Point": render.NewPoint,
"Self": vm.Self, // i.e., the uix.Actor object
"Events": vm.Events,
// Timer functions with APIs similar to the web browsers.
"setTimeout": vm.SetTimeout,
"setInterval": vm.SetInterval,
"clearTimeout": vm.ClearTimer,
"clearInterval": vm.ClearTimer,
}
for name, v := range bindings {
err := vm.vm.Set(name, v)
if err != nil {
return fmt.Errorf("RegisterLevelHooks(%s): %s",
name, err,
)
}
}
// Alias the console.log functions to the logger.
vm.vm.Run(`
console = {};
console.log = log.Info;
console.debug = log.Debug;
console.warn = log.Warn;
console.error = log.Error;
`)
return nil
}
// Main calls the main function of the script.
func (vm *VM) Main() error {
function, err := vm.vm.Get("main")
if err != nil {
return err
}
if !function.IsFunction() {
return nil
}
// Catch panics.
defer func() {
if err := recover(); err != nil {
log.Error("Panic caught in JavaScript VM: %s", err)
}
}()
_, err = function.Call(otto.Value{})
return err
}