1.1 --- a/libraries/mondelefant/mondelefant_native.c	Fri Dec 04 14:04:54 2015 +0100
     1.2 +++ b/libraries/mondelefant/mondelefant_native.c	Wed Dec 09 03:40:27 2015 +0100
     1.3 @@ -4,6 +4,7 @@
     1.4  #include <postgres.h>
     1.5  #include <catalog/pg_type.h>
     1.6  #include <stdint.h>
     1.7 +#include <time.h>
     1.8  
     1.9  // NOTE: Comments with format "// <number>" denote the Lua stack position
    1.10  
    1.11 @@ -310,6 +311,8 @@
    1.12    lua_getfield(L, LUA_REGISTRYINDEX, MONDELEFANT_CONN_DATA_REGKEY);  // 2
    1.13    lua_pushvalue(L, 1);  // 3
    1.14    lua_newtable(L);  // 4
    1.15 +  lua_pushinteger(L, PQsocket(pgconn));  // determine file descriptor
    1.16 +  lua_setfield(L, 4, "fd");  // set "fd" attribute
    1.17    lua_settable(L, 2);
    1.18    lua_settop(L, 1);
    1.19    // store key "engine" with value "postgresql" as connection specific data:
    1.20 @@ -402,6 +405,11 @@
    1.21    conn = mondelefant_get_conn(L, 1);
    1.22    PQfinish(conn->pgconn);
    1.23    conn->pgconn = NULL;
    1.24 +  lua_getfield(L, LUA_REGISTRYINDEX, MONDELEFANT_CONN_DATA_REGKEY);  // 2
    1.25 +  lua_pushvalue(L, 1);  // 3
    1.26 +  lua_gettable(L, 2);  // 3
    1.27 +  lua_pushnil(L);  // 4
    1.28 +  lua_setfield(L, 3, "fd");  // set "fd" attribute to nil
    1.29    return 0;
    1.30  }
    1.31  
    1.32 @@ -438,6 +446,88 @@
    1.33    return 1;
    1.34  }
    1.35  
    1.36 +// method "wait" of database handles:
    1.37 +static int mondelefant_conn_wait(lua_State *L) {
    1.38 +  mondelefant_conn_t *conn;
    1.39 +  int infinite, nonblock = 0;
    1.40 +  struct timespec wakeup;
    1.41 +  int fd;
    1.42 +  fd_set fds;
    1.43 +  conn = mondelefant_get_conn(L, 1);
    1.44 +  infinite = lua_isnoneornil(L, 2);
    1.45 +  if (!infinite) {
    1.46 +    lua_Number n;
    1.47 +    int isnum;
    1.48 +    n = lua_tonumberx(L, 2, &isnum);
    1.49 +    if (isnum && n>0 && n<=86400*366) {
    1.50 +      if (clock_gettime(CLOCK_MONOTONIC, &wakeup)) {
    1.51 +        return luaL_error(L, "Could not access CLOCK_MONOTONIC");
    1.52 +      }
    1.53 +      wakeup.tv_sec += n;
    1.54 +      wakeup.tv_nsec += 1000000000 * (n - (time_t)n);
    1.55 +      if (wakeup.tv_nsec >= 1000000000) {
    1.56 +        wakeup.tv_sec += 1;
    1.57 +        wakeup.tv_nsec -= 1000000000;
    1.58 +      }
    1.59 +    } else if (isnum && n==0) {
    1.60 +      nonblock = 1;
    1.61 +    } else {
    1.62 +      luaL_argcheck(L, 0, 2, "not a valid timeout");
    1.63 +    }
    1.64 +  }
    1.65 +  if (!nonblock) {
    1.66 +    fd = PQsocket(conn->pgconn);
    1.67 +    FD_ZERO(&fds);
    1.68 +    FD_SET(fd, &fds);
    1.69 +  }
    1.70 +  while (true) {
    1.71 +    {
    1.72 +      PGnotify *notify;
    1.73 +      if (!PQconsumeInput(conn->pgconn)) {
    1.74 +        lua_pushnil(L);
    1.75 +        mondelefant_push_first_line(L, PQerrorMessage(conn->pgconn));
    1.76 +        return 2;
    1.77 +      }
    1.78 +      notify = PQnotifies(conn->pgconn);
    1.79 +      if (notify) {
    1.80 +        lua_pushstring(L, notify->relname);
    1.81 +        lua_pushstring(L, notify->extra);
    1.82 +        lua_pushinteger(L, notify->be_pid);
    1.83 +        PQfreemem(notify);
    1.84 +        return 3;
    1.85 +      }
    1.86 +    }
    1.87 +    if (infinite) {
    1.88 +      select(fd+1, &fds, NULL, NULL, NULL);
    1.89 +    } else if (nonblock) {
    1.90 +      break;
    1.91 +    } else {
    1.92 +      struct timespec tp;
    1.93 +      struct timeval timeout = { 0, };
    1.94 +      if (clock_gettime(CLOCK_MONOTONIC, &tp)) {
    1.95 +        return luaL_error(L, "Could not access CLOCK_MONOTONIC");
    1.96 +      }
    1.97 +      tp.tv_sec = wakeup.tv_sec - tp.tv_sec;
    1.98 +      tp.tv_nsec = wakeup.tv_nsec - tp.tv_nsec;
    1.99 +      if (tp.tv_nsec < 0) {
   1.100 +        tp.tv_sec -= 1;
   1.101 +        tp.tv_nsec += 1000000000;
   1.102 +      }
   1.103 +      timeout.tv_sec = tp.tv_sec;
   1.104 +      timeout.tv_usec = (tp.tv_nsec + 500) / 1000;
   1.105 +      if (
   1.106 +        timeout.tv_sec < 0 ||
   1.107 +        (timeout.tv_sec == 0 && timeout.tv_usec == 0)
   1.108 +      ) break;
   1.109 +      select(fd+1, &fds, NULL, NULL, &timeout);
   1.110 +    }
   1.111 +  }
   1.112 +  lua_pushboolean(L, 0);
   1.113 +  if (nonblock) lua_pushliteral(L, "No notification pending");
   1.114 +  else lua_pushliteral(L, "Timeout while waiting for notification");
   1.115 +  return 2;
   1.116 +}
   1.117 +
   1.118  // method "create_list" of database handles:
   1.119  static int mondelefant_conn_create_list(lua_State *L) {
   1.120    // ensure that first argument is a database connection:
   1.121 @@ -1767,6 +1857,7 @@
   1.122    {"close", mondelefant_conn_close},
   1.123    {"is_ok", mondelefant_conn_is_ok},
   1.124    {"get_transaction_status", mondelefant_conn_get_transaction_status},
   1.125 +  {"wait", mondelefant_conn_wait},
   1.126    {"create_list", mondelefant_conn_create_list},
   1.127    {"create_object", mondelefant_conn_create_object},
   1.128    {"quote_string", mondelefant_conn_quote_string},