module/lua/lcorolib.c

   1 /*
   2 ** $Id: lcorolib.c,v 1.5.1.1 2013/04/12 18:48:47 roberto Exp $
   3 ** Coroutine Library
   4 ** See Copyright Notice in lua.h
   5 */
   6
   7
   8 #define lcorolib_c
   9 #define LUA_LIB
  10
  11 #include <sys/lua/lua.h>
  12
  13 #include <sys/lua/lauxlib.h>
  14 #include <sys/lua/lualib.h>
  15
  16
  17 static int auxresume (lua_State *L, lua_State *co, int narg) {
  18   int status;
  19   if (!lua_checkstack(co, narg)) {
  20     lua_pushliteral(L, "too many arguments to resume");
  21     return -1;  /* error flag */
  22   }
  23   if (lua_status(co) == LUA_OK && lua_gettop(co) == 0) {
  24     lua_pushliteral(L, "cannot resume dead coroutine");
  25     return -1;  /* error flag */
  26   }
  27   lua_xmove(L, co, narg);
  28   status = lua_resume(co, L, narg);
  29   if (status == LUA_OK || status == LUA_YIELD) {
  30     int nres = lua_gettop(co);
  31     if (!lua_checkstack(L, nres + 1)) {
  32       lua_pop(co, nres);  /* remove results anyway */
  33       lua_pushliteral(L, "too many results to resume");
  34       return -1;  /* error flag */
  35     }
  36     lua_xmove(co, L, nres);  /* move yielded values */
  37     return nres;
  38   }
  39   else {
  40     lua_xmove(co, L, 1);  /* move error message */
  41     return -1;  /* error flag */
  42   }
  43 }
  44
  45
  46 static int luaB_coresume (lua_State *L) {
  47   lua_State *co = lua_tothread(L, 1);
  48   int r;
  49   luaL_argcheck(L, co, 1, "coroutine expected");
  50   r = auxresume(L, co, lua_gettop(L) - 1);
  51   if (r < 0) {
  52     lua_pushboolean(L, 0);
  53     lua_insert(L, -2);
  54     return 2;  /* return false + error message */
  55   }
  56   else {
  57     lua_pushboolean(L, 1);
  58     lua_insert(L, -(r + 1));
  59     return r + 1;  /* return true + 'resume' returns */
  60   }
  61 }
  62
  63
  64 static int luaB_auxwrap (lua_State *L) {
  65   lua_State *co = lua_tothread(L, lua_upvalueindex(1));
  66   int r = auxresume(L, co, lua_gettop(L));
  67   if (r < 0) {
  68     if (lua_isstring(L, -1)) {  /* error object is a string? */
  69       luaL_where(L, 1);  /* add extra info */
  70       lua_insert(L, -2);
  71       lua_concat(L, 2);
  72     }
  73     return lua_error(L);  /* propagate error */
  74   }
  75   return r;
  76 }
  77
  78
  79 static int luaB_cocreate (lua_State *L) {
  80   lua_State *NL;
  81   luaL_checktype(L, 1, LUA_TFUNCTION);
  82   NL = lua_newthread(L);
  83   lua_pushvalue(L, 1);  /* move function to top */
  84   lua_xmove(L, NL, 1);  /* move function from L to NL */
  85   return 1;
  86 }
  87
  88
  89 static int luaB_cowrap (lua_State *L) {
  90   luaB_cocreate(L);
  91   lua_pushcclosure(L, luaB_auxwrap, 1);
  92   return 1;
  93 }
  94
  95
  96 static int luaB_yield (lua_State *L) {
  97   return lua_yield(L, lua_gettop(L));
  98 }
  99
 100
 101 static int luaB_costatus (lua_State *L) {
 102   lua_State *co = lua_tothread(L, 1);
 103   luaL_argcheck(L, co, 1, "coroutine expected");
 104   if (L == co) lua_pushliteral(L, "running");
 105   else {
 106     switch (lua_status(co)) {
 107       case LUA_YIELD:
 108         lua_pushliteral(L, "suspended");
 109         break;
 110       case LUA_OK: {
 111         lua_Debug ar;
 112         if (lua_getstack(co, 0, &ar) > 0)  /* does it have frames? */
 113           lua_pushliteral(L, "normal");  /* it is running */
 114         else if (lua_gettop(co) == 0)
 115             lua_pushliteral(L, "dead");
 116         else
 117           lua_pushliteral(L, "suspended");  /* initial state */
 118         break;
 119       }
 120       default:  /* some error occurred */
 121         lua_pushliteral(L, "dead");
 122         break;
 123     }
 124   }
 125   return 1;
 126 }
 127
 128
 129 static int luaB_corunning (lua_State *L) {
 130   int ismain = lua_pushthread(L);
 131   lua_pushboolean(L, ismain);
 132   return 2;
 133 }
 134
 135
 136 static const luaL_Reg co_funcs[] = {
 137   {"create", luaB_cocreate},
 138   {"resume", luaB_coresume},
 139   {"running", luaB_corunning},
 140   {"status", luaB_costatus},
 141   {"wrap", luaB_cowrap},
 142   {"yield", luaB_yield},
 143   {NULL, NULL}
 144 };
 145
 146
 147
 148 LUAMOD_API int luaopen_coroutine (lua_State *L) {
 149   luaL_newlib(L, co_funcs);
 150   return 1;
 151 }
 152
 153 #if defined(_KERNEL)
 154
 155 EXPORT_SYMBOL(luaopen_coroutine);
 156
 157 #endif