From bf35d691af919a79d1b418843c7417d8ed1c459f Mon Sep 17 00:00:00 2001
From: vedhavyas <vedhavyas.singareddi@gmail.com>
Date: Tue, 20 Aug 2019 14:29:13 -0700
Subject: [PATCH] more checks

---
 bridge.go           | 29 ++++++++++++++++++++++-------
 imports.go          |  2 +-
 simple/prog/main.go |  1 -
 3 files changed, 23 insertions(+), 9 deletions(-)

diff --git a/bridge.go b/bridge.go
index 3cc1134..16ad1eb 100644
--- a/bridge.go
+++ b/bridge.go
@@ -18,12 +18,15 @@ var bridges = map[string]*Bridge{}
 var mu sync.RWMutex // to protect bridges
 type context struct{ n string }
 
-// TODO ensure it  wont override the another context with same name.
-func setBridge(b *Bridge) unsafe.Pointer {
+func getCtxData(b *Bridge) (unsafe.Pointer, error) {
 	mu.Lock()
 	defer mu.Unlock()
+	if _, ok := bridges[b.name]; ok {
+		return nil, fmt.Errorf("bridge with name %s already exists", b.name)
+	}
+
 	bridges[b.name] = b
-	return unsafe.Pointer(&context{n: b.name})
+	return unsafe.Pointer(&context{n: b.name}), nil
 }
 
 func getBridge(ctx unsafe.Pointer) *Bridge {
@@ -42,6 +45,7 @@ type Bridge struct {
 	values   []interface{}
 	refs     map[interface{}]int
 	memory   []byte
+	exited   bool
 }
 
 func BridgeFromBytes(name string, bytes []byte, imports *wasmer.Imports) (*Bridge, error) {
@@ -61,8 +65,13 @@ func BridgeFromBytes(name string, bytes []byte, imports *wasmer.Imports) (*Bridg
 		return nil, err
 	}
 
+	ctx, err := getCtxData(b)
+	if err != nil {
+		return nil, err
+	}
+
 	b.instance = inst
-	inst.SetContextData(setBridge(b))
+	inst.SetContextData(ctx)
 	b.addValues()
 	b.refs = make(map[interface{}]int)
 	return b, nil
@@ -159,8 +168,15 @@ func (b *Bridge) addValues() {
 	}
 }
 
+func (b *Bridge) check() {
+	if b.exited {
+		panic("WASM instance already exited")
+	}
+}
+
 // Run start the wasm instance.
 func (b *Bridge) Run(init chan error, done chan bool) {
+	b.check()
 	defer b.instance.Close()
 
 	b.done = done
@@ -358,7 +374,7 @@ func (b *Bridge) storeValue(addr int32, v interface{}) {
 }
 
 type object struct {
-	name  string // TODO for debugging
+	name  string // for debugging
 	props map[string]interface{}
 	new   func(args []interface{}) interface{}
 }
@@ -422,8 +438,8 @@ func (b *Bridge) makeFuncWrapper(id, this interface{}, args *[]interface{}) (int
 	return event.props["result"], nil
 }
 
-// TODO cheeck if the wasm is still running
 func (b *Bridge) CallFunc(fn string, args []interface{}) (interface{}, error) {
+	b.check()
 	fw, ok := b.values[5].(*object).props[fn]
 	if !ok {
 		return nil, fmt.Errorf("missing function: %v", fn)
@@ -432,7 +448,6 @@ func (b *Bridge) CallFunc(fn string, args []interface{}) (interface{}, error) {
 	return b.makeFuncWrapper(fw.(*funcWrapper).id, b.values[7], &args)
 }
 
-// TODO check if wasm is still running
 func (b *Bridge) SetFunc(fname string, fn Func) error {
 	b.values[5].(*object).props[fname] = &fn
 	return nil
diff --git a/imports.go b/imports.go
index 95ed0cd..d7871ba 100644
--- a/imports.go
+++ b/imports.go
@@ -46,6 +46,7 @@ func debug(ctx unsafe.Pointer, sp int32) {
 func wexit(ctx unsafe.Pointer, sp int32) {
 	b := getBridge(ctx)
 	b.exitCode = int(b.getUint32(sp + 8))
+	b.exited = true
 	close(b.done)
 }
 
@@ -115,7 +116,6 @@ func valueGet(ctx unsafe.Pointer, sp int32) {
 
 	res, ok := obj.props[str]
 	if !ok {
-		// TODO
 		panic(fmt.Sprintln("missing property", str, val))
 	}
 	b.storeValue(sp+32, res)
diff --git a/simple/prog/main.go b/simple/prog/main.go
index 1a9043d..d0dfd1e 100644
--- a/simple/prog/main.go
+++ b/simple/prog/main.go
@@ -7,7 +7,6 @@ import (
 	"syscall/js"
 )
 
-// TODO: log seems to cause an issue
 func addition(this js.Value, args []js.Value) interface{} {
 	log.Println("In WASM", args)
 	a, b := args[0].Int(), args[1].Int()