/// Makes the LocalConnection object listen.
///
/// The name is a symbolic name like "lc1", that is used by the
/// send() command to signify which local connection to send the
/// object to.
//
/// When connect is called, this object adds its domain + name plus some
/// other bits of information to the listeners portion of the shared memory.
/// It also sets the initial bytes of the shared memory to a set
/// pattern.
//
/// The connection will fail if a listener with the same id (domain + name)
/// already exists. ActionScript isn't informed of this failure.
void
LocalConnection_as::connect(const std::string& name)
{
assert(!name.empty());
_name = name;
if (!_shm.attach()) {
log_error("Failed to open shared memory segment");
return;
}
SharedMem::iterator ptr = _shm.begin();
// We can't connect if there is already a listener with the same name.
if (!addListener(_domain + ":" + _name, _shm)) {
return;
}
const char i[] = { 1, 0, 0, 0, 1, 0, 0, 0 };
std::copy(i, i + 8, ptr);
movie_root& mr = getRoot(owner());
mr.addAdvanceCallback(this);
_connected = true;
return;
}
void
LocalConnection_as::update()
{
// Check whether local connection is disabled(!): brilliant choice of
// function name.
if (rcfile.getLocalConnection()) {
log_security("Attempting to write to disabled LocalConnection!");
movie_root& mr = getRoot(owner());
mr.removeAdvanceCallback(this);
return;
}
// No-op if already attached. Nothing to do if it fails, but we
// should probably stop trying.
if (!_shm.attach()) {
log_error("Failed to attach shared memory segment");
return;
}
// We need the lock to prevent simultaneous reads/writes from other
// processes.
SharedMem::Lock lock(_shm);
if (!lock.locked()) {
log_debug("Failed to get shm lock");
return;
}
SharedMem::iterator ptr = _shm.begin();
// First check timestamp data.
// These are not network byte order by default, but not sure about
// host byte order.
const boost::uint32_t timestamp = readLong(ptr + 8);
const boost::uint32_t size = readLong(ptr + 12);
// As long as there is a timestamp in the shared memory, we mustn't
// write anything.
//
// We check if this is data we are listening for. If it is, read it and
// mark for overwriting.
//
// If not, we keep checking until the data has been overwritten by
// another listener or until it's expired. If it's expired, we
// mark for overwriting.
if (timestamp) {
// Start after 16-byte header.
const boost::uint8_t* b = ptr + 16;
// End at reported size of AMF sequence.
const boost::uint8_t* end = b + size;
amf::Reader rd(b, end, getGlobal(owner()));
as_value a;
// Get the connection name. That's all we need to remove expired
// data.
if (!rd(a)) {
log_error("Invalid connection name data");
return;
}
const std::string& connection = a.to_string();
// Now check if data we wrote has expired. There's no really
// reliable way of checking that we genuinely wrote it.
if (_lastTime == timestamp) {
const size_t timeout = 4 * 1000;
VM& vm = getVM(owner());
const boost::uint32_t timeNow = getTimestamp(vm);
if (timeNow - timestamp > timeout) {
log_debug("Data %s expired at %s. Removing its target "
"as a listener", timestamp, timeNow);
removeListener(connection, _shm);
markRead(_shm);
_lastTime = 0;
}
}
// If we are listening and the data is for us, get the rest of it
// and call the method.
if (_connected && connection == _domain + ":" + _name) {
executeAMFFunction(owner(), rd);
// Zero the timestamp bytes to signal that the shared memory
// can be written again.
markRead(_shm);
}
else {
// The data has not expired and we didn't read it. Leave it
// alone until it's expired or someone else has read it.
return;
}
}
// If we have no data to send, there's nothing more to do.
if (_queue.empty()) {
// ...except remove the callback if we aren't listening for anything.
if (!_connected) {
movie_root& mr = getRoot(owner());
mr.removeAdvanceCallback(this);
}
return;
}
// Get the first buffer.
boost::shared_ptr<ConnectionData> cd = _queue.front();
_queue.pop_front();
// If the correct listener isn't there, iterate until we find one or
// there aren't any left.
while (!findListener(_domain + ":" + cd->name, _shm)) {
if (_queue.empty()) {
// Make sure we send the empty header later.
cd->ts = 0;
break;
}
cd = _queue.front();
_queue.pop_front();
}
// Yes, there is data to send.
const char i[] = { 1, 0, 0, 0, 1, 0, 0, 0 };
std::copy(i, i + arraySize(i), ptr);
SimpleBuffer& buf = cd->data;
SharedMem::iterator tmp = ptr + 8;
writeLong(tmp, cd->ts);
writeLong(tmp, cd->ts ? buf.size() : 0);
std::copy(buf.data(), buf.data() + buf.size(), tmp);
// Note the timestamp of our last send. We will keep calling update()
// until the data has expired or been read.
_lastTime = cd->ts;
}