/*
status = write_usb_msg(msg,[timeout])
writes a message to the CHDK ptp interface
msg may be nil, boolean, number, string or table (table has some restrictions, will be converted to string)
returns true if the message was queued successfully, otherwise false
if timeout is set and not zero, wait until message is written or timeout expires
NOTE strings will not include a terminating NULL, must be handled by recipient
*/
static int luaCB_write_usb_msg( lua_State* L )
{
ptp_script_msg *msg;
int timeout = luaL_optnumber( L, 2, 0 );
// TODO would it be better to either ignore this or return nil ?
// a write_usb_msg(function_which_returns_no_value()) is an error in this case
// replacing with nil might be more luaish
if(lua_gettop(L) < 1) {
return luaL_error(L,"missing argument");
}
msg=lua_create_usb_msg(L,1,PTP_CHDK_S_MSGTYPE_USER);
// for user messages, trying to create a message from an incompatible type throws an error
if(msg->subtype == PTP_CHDK_TYPE_UNSUPPORTED) {
free(msg);
return luaL_error(L,"unsupported type");
}
if(!msg) {
return luaL_error(L,"failed to create message");
}
if(timeout) {
action_push(timeout);
action_push((int)msg);
action_push(AS_SCRIPT_WRITE_USB_MSG);
return lua_yield( L, 0 );
}
lua_pushboolean(L,ptp_script_write_msg(msg));
return 1;
}
// convenience function write an error message
int ptp_script_write_error_msg(unsigned errtype, const char *err) {
if(script_msg_q_full(&msg_q_out)) {
return 0;
}
ptp_script_msg *msg = ptp_script_create_msg(PTP_CHDK_S_MSGTYPE_ERR,errtype,strlen(err),err);
if(!msg) {
return 0;
}
return ptp_script_write_msg(msg);
}
// TODO more stuff from script.c should be moved here
void lua_script_finish(lua_State *L)
{
#ifdef CAM_CHDK_PTP
if(lua_script_is_ptp) {
// send all return values as RET messages
int i,end = lua_gettop(L);
for(i=1; i<=end; i++) {
// if the queue is full return values will be silently discarded
// incompatible types will be returned as TYPE_UNSUPPORTED to preserve expected number and order of return values
ptp_script_write_msg(lua_create_usb_msg(L,i,PTP_CHDK_S_MSGTYPE_RET));
}
}
#endif
}
