inline optional<v8::Local<v8::Value>> objectMember(v8::Local<v8::Value> value, const char * name) {
Nan::EscapableHandleScope scope;
if (!Nan::Has(Nan::To<v8::Object>(value).ToLocalChecked(), Nan::New(name).ToLocalChecked()).FromJust()) {
return {};
}
Nan::MaybeLocal<v8::Value> result = Nan::Get(Nan::To<v8::Object>(value).ToLocalChecked(), Nan::New(name).ToLocalChecked());
if (result.IsEmpty()) {
return {};
}
return scope.Escape(result.ToLocalChecked());
}
/*
* Tcl proc to embed Javascript
*/
int jsEval(
ClientData clientData,
Tcl_Interp *interp,
int objc,
Tcl_Obj *const objv[]
){
v8log("TclBinding::jsEval (interp=%p)\n", interp);
// Get handle to the V8 Isolate for this Tcl interpreter
Isolate* isolate = v8::Isolate::GetCurrent();
assert(isolate != nullptr);
// lock the Isolate for multi-threaded access (not reentrant on its own)
Locker locker(isolate);
// create a bindings map and store it in the current V8 Isolate
TclVariableBindingsMap* varbindings = new TclVariableBindingsMap;
isolate->SetData(0, varbindings);
v8log("jsEval: created new bindings map at %lp\n", (void*)varbindings );
// validate input params
if ( (objc != 3) ) {
std::string msg("usage: jsEval [list of tcl vars to add to v8 context] { javascript }");
Tcl_SetObjResult(interp, Tcl_NewStringObj(msg.c_str(), msg.length()));
return TCL_ERROR;
}
// get the argument list
Tcl_Obj* arglist = objv[1];
if ( (arglist->typePtr == NULL) || strcmp(arglist->typePtr->name, "list") ) {
std::string msg("jsEval: 1st arg not a list");
Tcl_SetObjResult(interp, Tcl_NewStringObj(msg.c_str(), msg.length()));
return TCL_ERROR;
}
// get the JS snippet
char* javascript = Tcl_GetString(objv[2]);
if ( strlen(javascript) == 0 ) {
std::string msg("jsEval: 2nd arg not a string");
Tcl_SetObjResult(interp, Tcl_NewStringObj(msg.c_str(), msg.length()));
return TCL_ERROR;
}
// Create stack-allocated isolate and handle scopes.
Isolate::Scope isolate_scope(isolate);
HandleScope handle_scope(isolate);
// new v8 global template
Handle<ObjectTemplate> global_templ = ObjectTemplate::New(isolate);
// scrum our F18 Interceptors
global_templ->SetNamedPropertyHandler(
&TclVariableBinding::GenericNamedPropertyReader,
&TclVariableBinding::GenericNamedPropertyWriter
);
// Create and Enter a new context for compiling and running the script.
Handle<Context> context = Context::New(isolate, NULL, global_templ);
context->Enter();
int arglistLength;
Tcl_ListObjLength(interp, arglist, &arglistLength);
v8log("arg list length == %d\n", arglistLength);
for ( int i = 0; i < arglistLength; i++ ) {
// get the variable NAME
Tcl_Obj* varName;
Tcl_ListObjIndex(interp, arglist, i, &varName);
char* vn = Tcl_GetString(varName);
v8log("binding %s (idx: %d) to V8\n", vn, i);
// then create a binding and store it
(*varbindings)[vn] = new TclVariableBinding(interp, varName);
}
// Compile
v8log("compiling jsEval'ed script\n");
v8::MaybeLocal<v8::Script> jsSource = v8::Script::Compile(context, Nan::New<String>(javascript).ToLocalChecked());
if (jsSource.IsEmpty()) {
v8log("*** jsSource.IsEmpty()\n");
} else {
// Run
v8log("running jsEval'ed script\n");
Nan::TryCatch tc;
Nan::MaybeLocal<v8::Value> retv = jsSource.ToLocalChecked()->Run();
v8log("done running jsEval'ed script\n");
if ( tc.HasCaught() ) {
// oops, exception raised from V8 while in JS land
Local<Message> msg = tc.Message();
std::string msgtext(*String::Utf8Value(msg->Get()));
v8log("*** caught JS exception: %s\n", msgtext.c_str());
}
TclVariableBindingsMap::const_iterator it;
for (it = varbindings->begin(); it != varbindings->end(); it++) {
TclVariableBinding* vb = it->second;
v8log("reverse mapping of %s (v8: %p) to Tcl...\n", it->first.c_str(), vb->m_v8val);
Tcl_SetVar2Ex(vb->m_interp, it->first.c_str(), NULL, vb->m_tclvar, 0);
delete vb;
}
varbindings->clear();
// handle return value, if there is one
if (!retv.IsEmpty()) {
Local<Value> rv = retv.ToLocalChecked();
std::string res(*String::Utf8Value(rv));
std::string restype(V8ValueType(rv));
v8log("Tcl_SetObjResult(interp == %lp, result == %s (%s)\n", (void*) interp, res.c_str(), restype.c_str());
Tcl_Obj* tclres = V8ToTcl(interp, rv);
Tcl_SetObjResult(interp, tclres);
}
delete varbindings;
}
context->Exit();
// TODO: error handling!
return TCL_OK;
}