refactor: use custom event emitter (#193)

* refactor: use custom event emitter

* fix: sigint hook emit on windows

* fix: restore correct hilbish conf file

* fix: call recoverer for go listeners

* refactor(golibs/bait): use 1 map for listeners

* feat: add once listeners, ability to remove listeners and remove listener on error

* perf: reslice listener slice instead of trying to do ordered move with append

* feat(bait): add release function to remove event listener

* perf: remove listener directly from once emit instead of using off function

* refactor: use bait event emitter on commander

* docs(golibs/bait): add doc strings for functions

* docs: set changelog

* docs(golibs/bait): add docs for lua release function

CHANGELOG.md

@@ -70,6 +70,11 @@ set `hilbish.opts.motd` to false.
 disables commands being added to history.
 - `hilbish.rawInput` hook for input from the readline library
 - Completion of files in quotes
+- A new and "safer" event emitter has been added. This causes a performance deficit, but avoids a lot of
+random errors introduced with the new Lua runtime (see [#197])
+- `bait.release(name, catcher)` removes `handler` for the named `event`
+
+[#197]: https://github.com/Rosettea/Hilbish/issues/197
 
 ### Changed
 - **Breaking Change:** Upgraded to Lua 5.4.

api.go

@@ -189,7 +189,7 @@ func getenv(key, fallback string) string {
 
 func setVimMode(mode string) {
 	util.SetField(l, hshMod, "vimMode", rt.StringValue(mode), "Current Vim mode of Hilbish (nil if not in Vim mode)")
-	hooks.Em.Emit("hilbish.vimMode", mode)
+	hooks.Emit("hilbish.vimMode", mode)
 }
 
 func unsetVimMode() {

exec.go

@@ -85,7 +85,7 @@ func isExecError(err error) (execError, bool) {
 func runInput(input string, priv bool) {
 	running = true
 	cmdString := aliases.Resolve(input)
-	hooks.Em.Emit("command.preexec", input, cmdString)
+	hooks.Emit("command.preexec", input, cmdString)
 
 	rerun:
 	var exitCode uint8
@@ -140,7 +140,7 @@ func runInput(input string, priv bool) {
 
 	if err != nil {
 		if exErr, ok := isExecError(err); ok {
-			hooks.Em.Emit("command." + exErr.typ, exErr.cmd)
+			hooks.Emit("command." + exErr.typ, exErr.cmd)
 			err = exErr.sprint()
 		}
 		fmt.Fprintln(os.Stderr, err)
@@ -544,5 +544,5 @@ func cmdFinish(code uint8, cmdstr string, private bool) {
 	// using AsValue (to convert to lua type) on an interface which is an int
 	// results in it being unknown in lua .... ????
 	// so we allow the hook handler to take lua runtime Values
-	hooks.Em.Emit("command.exit", rt.IntValue(int64(code)), cmdstr, private)
+	hooks.Emit("command.exit", rt.IntValue(int64(code)), cmdstr, private)
 }

golibs/bait/bait.go

@@ -1,27 +1,41 @@
 package bait
 
 import (
-	"fmt"
 	"hilbish/util"
 
 	rt "github.com/arnodel/golua/runtime"
 	"github.com/arnodel/golua/lib/packagelib"
-	"github.com/chuckpreslar/emission"
 )
 
-type Bait struct{
-	Em *emission.Emitter
-	Loader packagelib.Loader
+type listenerType int
+const (
+	goListener listenerType = iota
+	luaListener
+)
+
+// Recoverer is a function which is called when a panic occurs in an event.
+type Recoverer func(event string, handler *Listener, err interface{})
+
+// Listener is a struct that holds the handler for an event.
+type Listener struct{
+	typ listenerType
+	once bool
+	caller func(...interface{})
+	luaCaller *rt.Closure
 }
 
-func New() Bait {
-	emitter := emission.NewEmitter()
-	emitter.RecoverWith(func(hookname, hookfunc interface{}, err error) {
-		emitter.Off(hookname, hookfunc)
-		fmt.Println(err)
-	})
-	b := Bait{
-		Em: emitter,
+type Bait struct{
+	Loader packagelib.Loader
+	recoverer Recoverer
+	handlers map[string][]*Listener
+	rtm *rt.Runtime
+}
+
+// New creates a new Bait instance.
+func New(rtm *rt.Runtime) *Bait {
+	b := &Bait{
+		handlers: make(map[string][]*Listener),
+		rtm: rtm,
 	}
 	b.Loader = packagelib.Loader{
 		Load: b.loaderFunc,
@@ -31,11 +45,148 @@ func New() Bait {
 	return b
 }
 
+// Emit throws an event.
+func (b *Bait) Emit(event string, args ...interface{}) {
+	handles := b.handlers[event]
+	if handles == nil {
+		return
+	}
+
+	for idx, handle := range handles {
+		defer func() {
+			if err := recover(); err != nil {
+				b.callRecoverer(event, handle, err)
+			}
+		}()
+
+		if handle.typ == luaListener {
+			funcVal := rt.FunctionValue(handle.luaCaller)
+			var luaArgs []rt.Value
+			for _, arg := range args {
+				var luarg rt.Value
+				switch arg.(type) {
+					case rt.Value: luarg = arg.(rt.Value)
+					default: luarg = rt.AsValue(arg)
+				}
+				luaArgs = append(luaArgs, luarg)
+			}
+			_, err := rt.Call1(b.rtm.MainThread(), funcVal, luaArgs...)
+			if err != nil {
+				// panicking here won't actually cause hilbish to panic and instead will
+				// print the error and remove the hook. reference the recoverer function in lua.go
+				panic(err)
+			}
+		} else {
+			handle.caller(args...)
+		}
+
+		if handle.once {
+			b.removeListener(event, idx)
+		}
+	}
+}
+
+// On adds a Go function handler for an event.
+func (b *Bait) On(event string, handler func(...interface{})) *Listener {
+	listener := &Listener{
+		typ: goListener,
+		caller: handler,
+	}
+
+	b.addListener(event, listener)
+	return listener
+}
+
+// OnLua adds a Lua function handler for an event.
+func (b *Bait) OnLua(event string, handler *rt.Closure) *Listener {
+	listener :=&Listener{
+		typ: luaListener,
+		luaCaller: handler,
+	}
+	b.addListener(event, listener)
+
+	return listener
+}
+
+// Off removes a Go function handler for an event.
+func (b *Bait) Off(event string, listener *Listener) {
+	handles := b.handlers[event]
+
+	for i, handle := range handles {
+		if handle == listener {
+			b.removeListener(event, i)
+		}
+	}
+}
+
+// OffLua removes a Lua function handler for an event.
+func (b *Bait) OffLua(event string, handler *rt.Closure) {
+	handles := b.handlers[event]
+
+	for i, handle := range handles {
+		if handle.luaCaller == handler {
+			b.removeListener(event, i)
+		}
+	}
+}
+
+// Once adds a Go function listener for an event that only runs once.
+func (b *Bait) Once(event string, handler func(...interface{})) *Listener {
+	listener := &Listener{
+		typ: goListener,
+		once: true,
+		caller: handler,
+	}
+	b.addListener(event, listener)
+
+	return listener
+}
+
+// OnceLua adds a Lua function listener for an event that only runs once.
+func (b *Bait) OnceLua(event string, handler *rt.Closure) *Listener {
+	listener := &Listener{
+		typ: luaListener,
+		once: true,
+		luaCaller: handler,
+	}
+	b.addListener(event, listener)
+
+	return listener
+}
+
+// SetRecoverer sets the function to be executed when a panic occurs in an event.
+func (b *Bait) SetRecoverer(recoverer Recoverer) {
+	b.recoverer = recoverer
+}
+
+func (b *Bait) addListener(event string, listener *Listener) {
+	if b.handlers[event] == nil {
+		b.handlers[event] = []*Listener{}
+	}
+
+	b.handlers[event] = append(b.handlers[event], listener)
+}
+
+
+func (b *Bait) removeListener(event string, idx int) {
+	b.handlers[event][idx] = b.handlers[event][len(b.handlers[event]) - 1]
+
+	b.handlers[event] = b.handlers[event][:len(b.handlers[event]) - 1]
+}
+
+func (b *Bait) callRecoverer(event string, handler *Listener, err interface{}) {
+	if b.recoverer == nil {
+		panic(err)
+	}
+	b.recoverer(event, handler, err)
+}
+
 func (b *Bait) loaderFunc(rtm *rt.Runtime) (rt.Value, func()) {
 	exports := map[string]util.LuaExport{
 		"catch": util.LuaExport{b.bcatch, 2, false},
 		"catchOnce": util.LuaExport{b.bcatchOnce, 2, false},
 		"throw": util.LuaExport{b.bthrow, 1, true},
+		"release": util.LuaExport{b.brelease, 2, false},
 	}
 	mod := rt.NewTable()
 	util.SetExports(rtm, mod, exports)
@@ -89,7 +240,7 @@ func (b *Bait) bthrow(t *rt.Thread, c *rt.GoCont) (rt.Cont, error) {
 	for i, v := range c.Etc() {
 		ifaceSlice[i] = v
 	}
-	b.Em.Emit(name, ifaceSlice...)
+	b.Emit(name, ifaceSlice...)
 
 	return c.Next(), nil
 }
@@ -104,9 +255,7 @@ func (b *Bait) bcatch(t *rt.Thread, c *rt.GoCont) (rt.Cont, error) {
 		return nil, err
 	}
 
-	b.Em.On(name, func(args ...interface{}) {
-		handleHook(t, c, name, catcher, args...)
-	})
+	b.OnLua(name, catcher)
 
 	return c.Next(), nil
 }
@@ -121,9 +270,22 @@ func (b *Bait) bcatchOnce(t *rt.Thread, c *rt.GoCont) (rt.Cont, error) {
 		return nil, err
 	}
 
-	b.Em.Once(name, func(args ...interface{}) {
-		handleHook(t, c, name, catcher, args...)
-	})
+	b.OnceLua(name, catcher)
+
+	return c.Next(), nil
+}
+
+// release(name, catcher)
+// Removes the `catcher` for the event with `name`
+// For this to work, `catcher` has to be the same function used to catch
+// an event, like one saved to a variable.
+func (b *Bait) brelease(t *rt.Thread, c *rt.GoCont) (rt.Cont, error) {
+	name, catcher, err := util.HandleStrCallback(t, c)
+	if err != nil {
+		return nil, err
+	}
+
+	b.OffLua(name, catcher)
 
 	return c.Next(), nil
 }

golibs/commander/commander.go

@@ -2,20 +2,20 @@ package commander
 
 import (
 	"hilbish/util"
+	"hilbish/golibs/bait"
 
 	rt "github.com/arnodel/golua/runtime"
 	"github.com/arnodel/golua/lib/packagelib"
-	"github.com/chuckpreslar/emission"
 )
 
 type Commander struct{
-	Events *emission.Emitter
+	Events *bait.Bait
 	Loader packagelib.Loader
 }
 
-func New() Commander {
+func New(rtm *rt.Runtime) Commander {
 	c := Commander{
-		Events: emission.NewEmitter(),
+		Events: bait.New(rtm),
 	}
 	c.Loader = packagelib.Loader{
 		Load: c.loaderFunc,

job.go

@@ -67,7 +67,7 @@ func (j *job) start() error {
 	j.pid = proc.Pid
 	j.running = true
 
-	hooks.Em.Emit("job.start", rt.UserDataValue(j.ud))
+	hooks.Emit("job.start", rt.UserDataValue(j.ud))
 
 	return err
 }
@@ -82,7 +82,7 @@ func (j *job) stop() {
 
 func (j *job) finish() {
 	j.running = false
-	hooks.Em.Emit("job.done", rt.UserDataValue(j.ud))
+	hooks.Emit("job.done", rt.UserDataValue(j.ud))
 }
 
 func (j *job) wait() {
@@ -236,7 +236,7 @@ func (j *jobHandler) add(cmd string, args []string, path string) *job {
 	jb.ud = jobUserData(jb)
 
 	j.jobs[j.latestID] = jb
-	hooks.Em.Emit("job.add", rt.UserDataValue(jb.ud))
+	hooks.Emit("job.add", rt.UserDataValue(jb.ud))
 
 	return jb
 }

lua.go

@@ -32,28 +32,38 @@ func luaInit() {
 	lib.LoadLibs(l, fs.Loader)
 	lib.LoadLibs(l, terminal.Loader)
 
-	cmds := commander.New()
+	cmds := commander.New(l)
 	// When a command from Lua is added, register it for use
-	cmds.Events.On("commandRegister", func(cmdName string, cmd *rt.Closure) {
+	cmds.Events.On("commandRegister", func(args ...interface{}) {
+		cmdName := args[0].(string)
+		cmd := args[1].(*rt.Closure)
+
 		commands[cmdName] = cmd
 	})
-	cmds.Events.On("commandDeregister", func(cmdName string) {
+	cmds.Events.On("commandDeregister", func(args ...interface{}) {
+		cmdName := args[0].(string)
+
 		delete(commands, cmdName)
 	})
 	lib.LoadLibs(l, cmds.Loader)
 
-	hooks = bait.New()
+	hooks = bait.New(l)
+	hooks.SetRecoverer(func(event string, handler *bait.Listener, err interface{}) {
+		fmt.Println("Error in", event, "event:", err)
+		hooks.Off(event, handler)
+	})
+
 	lib.LoadLibs(l, hooks.Loader)
 
 	// Add Ctrl-C handler
-	hooks.Em.On("signal.sigint", func() {
+	hooks.On("signal.sigint", func(...interface{}) {
 		if !interactive {
 			os.Exit(0)
 		}
 	})
 
 	lr.rl.RawInputCallback = func(r []rune) {
-		hooks.Em.Emit("hilbish.rawInput", string(r))
+		hooks.Emit("hilbish.rawInput", string(r))
 	}
 
 	// Add more paths that Lua can require from

main.go

@@ -30,7 +30,7 @@ var (
 	userDataDir string
 	curuser *user.User
 
-	hooks bait.Bait
+	hooks *bait.Bait
 	defaultConfPath string
 	defaultHistPath string
 )
@@ -138,7 +138,7 @@ func main() {
 	} else {
 		runConfig(*configflag)
 	}
-	hooks.Em.Emit("hilbish.init")
+	hooks.Emit("hilbish.init")
 
 	if fileInfo, _ := os.Stdin.Stat(); (fileInfo.Mode() & os.ModeCharDevice) == 0 {
 		scanner := bufio.NewScanner(bufio.NewReader(os.Stdin))
@@ -177,7 +177,7 @@ input:
 
 		if err == io.EOF {
 			// Exit if user presses ^D (ctrl + d)
-			hooks.Em.Emit("hilbish.exit")
+			hooks.Emit("hilbish.exit")
 			break
 		}
 		if err != nil {
@@ -196,7 +196,7 @@ input:
 		input = strings.TrimSpace(input)
 		if len(input) == 0 {
 			running = true
-			hooks.Em.Emit("command.exit", 0)
+			hooks.Emit("command.exit", 0)
 			continue
 		}
 
@@ -227,7 +227,7 @@ input:
 }
 
 func continuePrompt(prev string) (string, error) {
-	hooks.Em.Emit("multiline", nil)
+	hooks.Emit("multiline", nil)
 	lr.SetPrompt(multilinePrompt)
 	cont, err := lr.Read()
 	if err != nil {

rl.go

@@ -48,7 +48,7 @@ func newLineReader(prompt string, noHist bool) *lineReader {
 			case readline.VimActionPaste: actionStr = "paste"
 			case readline.VimActionYank: actionStr = "yank"
 		}
-		hooks.Em.Emit("hilbish.vimAction", actionStr, args)
+		hooks.Emit("hilbish.vimAction", actionStr, args)
 	}
 	rl.HintText = func(line []rune, pos int) []rune {
 		if hinter == nil {
@@ -179,7 +179,7 @@ func newLineReader(prompt string, noHist bool) *lineReader {
 }
 
 func (lr *lineReader) Read() (string, error) {
-	hooks.Em.Emit("command.precmd", nil)
+	hooks.Emit("command.precmd", nil)
 	s, err := lr.rl.Readline()
 	// this is so dumb
 	if err == readline.EOF {

signal_unix.go

@@ -15,11 +15,11 @@ func handleSignals() {
 
 	for s := range c {
 		switch s {
-		case os.Interrupt: hooks.Em.Emit("signal.sigint")
+		case os.Interrupt: hooks.Emit("signal.sigint")
 		case syscall.SIGTERM: exit(0)
-		case syscall.SIGWINCH: hooks.Em.Emit("signal.resize")
-		case syscall.SIGUSR1: hooks.Em.Emit("signal.sigusr1")
-		case syscall.SIGUSR2: hooks.Em.Emit("signal.sigusr2")
+		case syscall.SIGWINCH: hooks.Emit("signal.resize")
+		case syscall.SIGUSR1: hooks.Emit("signal.sigusr1")
+		case syscall.SIGUSR2: hooks.Emit("signal.sigusr2")
 		}
 	}
 }

signal_windows.go

@@ -14,7 +14,7 @@ func handleSignals() {
 	for s := range c {
 		switch s {
 		case os.Interrupt:
-			hooks.Em.Emit("signal.sigint")
+			hooks.Emit("signal.sigint")
 			if !running && interactive {
 				lr.ClearInput()
 			}