module/lua/lcorolib.c

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