Noah Petherbridge
4d08bf1d85
* Switch from otto to goja for JavaScript engine. * goja supports many ES6 syntax features like arrow functions, const/let, for-of with more coming soon. * Same great features as otto, more modern environment for doodads!
97 lines
2.2 KiB
Go
97 lines
2.2 KiB
Go
package scripting
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import (
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"errors"
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"fmt"
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"sync"
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"git.kirsle.net/apps/doodle/pkg/log"
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"github.com/dop251/goja"
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)
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// VM manages a single isolated JavaScript VM.
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type VM struct {
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Name string
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// Globals available to the scripts.
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Events *Events
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Self interface{}
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// Channels for inbound and outbound PubSub messages.
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// Each VM has a single Inbound channel that watches for received messages
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// and invokes the Message.Subscribe() handlers for relevant ones.
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// Each VM also has an array of Outbound channels which map to the Inbound
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// channel of the VMs it is linked to, for pushing out Message.Publish()
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// messages.
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Inbound chan Message
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Outbound []chan Message
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subscribe map[string][]goja.Value // Subscribed message handlers by name.
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muSubscribe sync.RWMutex
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vm *goja.Runtime
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// setTimeout and setInterval variables.
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timerLastID int // becomes 1 when first timer is set
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timers map[int]*Timer
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}
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// NewVM creates a new JavaScript VM.
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func NewVM(name string) *VM {
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vm := &VM{
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Name: name,
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vm: goja.New(),
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timers: map[int]*Timer{},
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// Pub/sub structs.
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Inbound: make(chan Message),
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Outbound: []chan Message{},
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subscribe: map[string][]goja.Value{},
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}
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vm.Events = NewEvents(vm.vm)
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return vm
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}
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// Run code in the VM.
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func (vm *VM) Run(src string) (goja.Value, error) {
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v, err := vm.vm.RunString(src)
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return v, err
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}
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// Set a value in the VM.
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func (vm *VM) Set(name string, v interface{}) error {
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return vm.vm.Set(name, v)
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}
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// RegisterLevelHooks registers accessors to the level hooks
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// and Doodad API for Play Mode.
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func (vm *VM) RegisterLevelHooks() error {
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bindings := NewJSProxy(vm)
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for name, v := range bindings {
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err := vm.vm.Set(name, v)
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if err != nil {
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return fmt.Errorf("RegisterLevelHooks(%s): %s",
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name, err,
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)
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}
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}
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return nil
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}
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// Main calls the main function of the script.
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func (vm *VM) Main() error {
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function, ok := goja.AssertFunction(vm.vm.Get("main"))
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if !ok {
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return errors.New("didn't find function main()")
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}
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// Catch panics.
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defer func() {
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if err := recover(); err != nil {
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log.Error("Panic caught in JavaScript VM: %s", err)
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}
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}()
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_, err := function(goja.Undefined())
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return err
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}
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