git.squeep.com Git - lemu/blob - lua_interface.c

   1 #include <stdlib.h>
   2
   3 #include <lua.h>
   4 #include <lualib.h>
   5 #include <lauxlib.h>
   6
   7 #include "connections.h"
   8 #include "lua_interface.h"
   9 #include "notify.h"
  10
  11 #define CONNECTION_META_TABLE "MetaConnection"
  12 #define CONNECTION_TABLE "Connection"
  13 #define CONNECTION_TABLE_UD_FIELD "core_"
  14
  15 /**
  16  * HARD: shared common server state, updatable commands table
  17  * Interim: independent states, any global changes queued to all workers
  18  * Idea: can a proxy table be crafted to access a shared table-like c entity
  19  * Idea: eventual-consistency between lua states (somehow)
  20  *
  21  */
  22
  23
  24 /**
  25  * Create a new referenced coroutine on lua state.
  26  * release with:
  27  *   luaL_unref(L, LUA_REGISTRYINDEX, refkey);
  28  */
  29 int
  30 lua_new_coroutine_ref(lua_State *L, lua_State **coL, int *refkey)
  31 {
  32         *refkey = LUA_NOREF;
  33
  34         /* Create new coroutine on top of stack. */
  35         *coL = lua_newthread(L);
  36         if (!*coL) {
  37                 NOTIFY_ERROR("%s:%s", "lua_newthread", "failed");
  38                 return -1;
  39         }
  40
  41         /* Store coroutine reference in state registry. */
  42         *refkey = luaL_ref(L, LUA_REGISTRYINDEX);
  43
  44         return 0;
  45 }
  46
  47
  48 /**
  49  * Connection Object
  50  * is a table with metatable for methods and userdata field
  51  *
  52  */
  53
  54
  55 /**
  56  * Add a connection reference to lua stack
  57  *
  58  */
  59 int
  60 lemu_connection_push(lua_State *L, struct connection *c)
  61 {
  62         connection_inc_ref(c);
  63
  64         lua_newtable(L); // new connection table
  65         luaL_getmetatable(L, CONNECTION_META_TABLE); // locate meta
  66         lua_setmetatable(L, -2); // assign meta to connection table
  67
  68         /* keeping a pointer in userdata, rather than light userdata, to get metatable support */
  69         struct connection **cud = lua_newuserdatauv(L, sizeof c, 0);
  70         *cud = c;
  71         luaL_getmetatable(L, CONNECTION_META_TABLE);
  72         lua_setmetatable(L, -2);
  73
  74         lua_setfield(L, -2, CONNECTION_TABLE_UD_FIELD);
  75         return 1;
  76 }
  77
  78
  79 /**
  80  * I guess this one would take a stack value to find a connection
  81  */
  82 static int
  83 lemu_connection_create_(lua_State *L)
  84 {
  85         struct connection *c;
  86
  87         luaL_checktype(L, 1, LUA_TSTRING);
  88         // c = connection_lookup(lua_tostring(L, 1));
  89         c = NULL;
  90
  91         return lemu_connection_push(L, c);
  92 }
  93
  94
  95 /**
  96  * this will only get called on userdata (how does that happen??)
  97  */
  98 static int
  99 lemu_connection_destroy_(lua_State *L)
 100 {
 101         struct connection **cud = luaL_checkudata(L, 1, CONNECTION_META_TABLE);
 102         struct connection *c = *cud;
 103
 104         connection_free(c);
 105
 106         return 0;
 107 }
 108
 109
 110 /**
 111  * Send a fixed string to a connection.
 112  */
 113 static int
 114 lemu_connection_send_(lua_State *L)
 115 {
 116         if (lua_gettop(L) < 2) {
 117                 lua_pushliteral(L, "too few arguments");
 118                 lua_error(L);
 119         }
 120         luaL_checktype(L, 1, LUA_TTABLE);
 121         lua_getfield(L, 1, CONNECTION_TABLE_UD_FIELD);
 122         luaL_checktype(L, -1, LUA_TUSERDATA);
 123         struct connection **cud = lua_touserdata(L, -1);
 124         struct connection *c = *cud;
 125
 126         luaL_checktype(L, 2, LUA_TSTRING);
 127         const char *message = lua_tostring(L, 2);
 128
 129         connection_printf(c, "%s\n", message);
 130
 131         return 0;
 132 }
 133
 134
 135 static const luaL_Reg Connection_funcs[] = {
 136         { "create", lemu_connection_create_ },
 137         { NULL, NULL }
 138 };
 139
 140
 141 static const luaL_Reg Connection_methods[] = {
 142         { "__gc", lemu_connection_destroy_ },
 143         { "send", lemu_connection_send_ },
 144         { NULL, NULL }
 145 };
 146
 147
 148 /**
 149  * Initialize the Connection object prototypes
 150  */
 151 int
 152 lemu_connection_luainit(lua_State *L)
 153 {
 154         luaL_newmetatable(L, CONNECTION_META_TABLE); // new userdata metatable, __name = CONNECTION_META_TABLE
 155         lua_pushstring(L, "__index");
 156         lua_pushvalue(L, -2); // meta table
 157         lua_settable(L, -3); // becomes its own index table
 158         luaL_setfuncs(L, Connection_methods, 0); // add methods to metatable
 159         lua_pop(L, 1);
 160
 161         luaL_newlibtable(L, Connection_funcs); // new table with functions
 162         luaL_setfuncs(L, Connection_funcs, 0);
 163         lua_setglobal(L, CONNECTION_TABLE); // make it available
 164
 165         return 0;
 166 }
 167
 168 // int luaopen_lemu(lua_State *L);