rsql.pike

// Remote SQL server interface

#define RSQL_PORT 3994
#define RSQL_VERSION 1


#if constant(thread_create)
#define LOCK object key=mutex->lock()
#define UNLOCK destruct(key)
static private object(Thread.Mutex) mutex = Thread.Mutex();
#else
#define LOCK
#define UNLOCK
#endif


static object(Stdio.File) sock;
static int seqno = 0;

static private string host, user, pw;
static private int port;

static void low_reconnect()
{
  object losock = Stdio.File();
  if(sock)
    destruct(sock);
  if(!losock->connect(host, port|RSQL_PORT))
    throw(({"Can't connect to "+host+(port? ":"+port:"")+": "+
	    strerror(losock->errno())+"\n", backtrace()}));
  if(8!=losock->write(sprintf("RSQL%4c", RSQL_VERSION)) ||
     losock->read(4) != "SQL!") {
    destruct(losock);
    throw(({"Initial handshake error on "+host+(port? ":"+port:"")+"\n",
	    backtrace()}));    
  }
  sock = losock;
  if(!do_request('L', ({user,pw}), 1)) {
    sock = 0;
    if(losock)
      destruct(losock);
    throw(({"Login refused on "+host+(port? ":"+port:"")+"\n",
	    backtrace()}));        
  }
}

static void low_connect(string the_host, int the_port, string the_user,
			string the_pw)
{
  host = the_host;
  port = the_port;
  user = the_user;
  pw = the_pw;
  low_reconnect();
}

static mixed do_request(int cmd, mixed|void arg, int|void noreconnect)
{
  LOCK;
  if(!sock)
    if(noreconnect) {
      UNLOCK;
      throw(({"No connection\n", backtrace()}));
    } else
      low_reconnect();
  arg = (arg? encode_value(arg) : "");
  sock->write(sprintf("?<%c>%4c%4c%s", cmd, ++seqno, sizeof(arg), arg));
  string res;
  int rlen;
  if((res = sock->read(12)) && sizeof(res)==12 &&