external/mit/lua/dist/src/lcorolib.c

   1 /*      $NetBSD: lcorolib.c,v 1.2 2015/02/02 14:03:05 lneto Exp $       */
   2
   3 /*
   4 ** Id: lcorolib.c,v 1.9 2014/11/02 19:19:04 roberto Exp
   5 ** Coroutine Library
   6 ** See Copyright Notice in lua.h
   7 */
   8
   9 #define lcorolib_c
  10 #define LUA_LIB
  11
  12 #include "lprefix.h"
  13
  14
  15 #ifndef _KERNEL
  16 #include <stdlib.h>
  17 #endif
  18
  19 #include "lua.h"
  20
  21 #include "lauxlib.h"
  22 #include "lualib.h"
  23
  24
  25 static lua_State *getco (lua_State *L) {
  26   lua_State *co = lua_tothread(L, 1);
  27   luaL_argcheck(L, co, 1, "thread expected");
  28   return co;
  29 }
  30
  31
  32 static int auxresume (lua_State *L, lua_State *co, int narg) {
  33   int status;
  34   if (!lua_checkstack(co, narg)) {
  35     lua_pushliteral(L, "too many arguments to resume");
  36     return -1;  /* error flag */
  37   }
  38   if (lua_status(co) == LUA_OK && lua_gettop(co) == 0) {
  39     lua_pushliteral(L, "cannot resume dead coroutine");
  40     return -1;  /* error flag */
  41   }
  42   lua_xmove(L, co, narg);
  43   status = lua_resume(co, L, narg);
  44   if (status == LUA_OK || status == LUA_YIELD) {
  45     int nres = lua_gettop(co);
  46     if (!lua_checkstack(L, nres + 1)) {
  47       lua_pop(co, nres);  /* remove results anyway */
  48       lua_pushliteral(L, "too many results to resume");
  49       return -1;  /* error flag */
  50     }
  51     lua_xmove(co, L, nres);  /* move yielded values */
  52     return nres;
  53   }
  54   else {
  55     lua_xmove(co, L, 1);  /* move error message */
  56     return -1;  /* error flag */
  57   }
  58 }
  59
  60
  61 static int luaB_coresume (lua_State *L) {
  62   lua_State *co = getco(L);
  63   int r;
  64   r = auxresume(L, co, lua_gettop(L) - 1);
  65   if (r < 0) {
  66     lua_pushboolean(L, 0);
  67     lua_insert(L, -2);
  68     return 2;  /* return false + error message */
  69   }
  70   else {
  71     lua_pushboolean(L, 1);
  72     lua_insert(L, -(r + 1));
  73     return r + 1;  /* return true + 'resume' returns */
  74   }
  75 }
  76
  77
  78 static int luaB_auxwrap (lua_State *L) {
  79   lua_State *co = lua_tothread(L, lua_upvalueindex(1));
  80   int r = auxresume(L, co, lua_gettop(L));
  81   if (r < 0) {
  82     if (lua_isstring(L, -1)) {  /* error object is a string? */
  83       luaL_where(L, 1);  /* add extra info */
  84       lua_insert(L, -2);
  85       lua_concat(L, 2);
  86     }
  87     return lua_error(L);  /* propagate error */
  88   }
  89   return r;
  90 }
  91
  92
  93 static int luaB_cocreate (lua_State *L) {
  94   lua_State *NL;
  95   luaL_checktype(L, 1, LUA_TFUNCTION);
  96   NL = lua_newthread(L);
  97   lua_pushvalue(L, 1);  /* move function to top */
  98   lua_xmove(L, NL, 1);  /* move function from L to NL */
  99   return 1;
 100 }
 101
 102
 103 static int luaB_cowrap (lua_State *L) {
 104   luaB_cocreate(L);
 105   lua_pushcclosure(L, luaB_auxwrap, 1);
 106   return 1;
 107 }
 108
 109
 110 static int luaB_yield (lua_State *L) {
 111   return lua_yield(L, lua_gettop(L));
 112 }
 113
 114
 115 static int luaB_costatus (lua_State *L) {
 116   lua_State *co = getco(L);
 117   if (L == co) lua_pushliteral(L, "running");
 118   else {
 119     switch (lua_status(co)) {
 120       case LUA_YIELD:
 121         lua_pushliteral(L, "suspended");
 122         break;
 123       case LUA_OK: {
 124         lua_Debug ar;
 125         if (lua_getstack(co, 0, &ar) > 0)  /* does it have frames? */
 126           lua_pushliteral(L, "normal");  /* it is running */
 127         else if (lua_gettop(co) == 0)
 128             lua_pushliteral(L, "dead");
 129         else
 130           lua_pushliteral(L, "suspended");  /* initial state */
 131         break;
 132       }
 133       default:  /* some error occurred */
 134         lua_pushliteral(L, "dead");
 135         break;
 136     }
 137   }
 138   return 1;
 139 }
 140
 141
 142 static int luaB_yieldable (lua_State *L) {
 143   lua_pushboolean(L, lua_isyieldable(L));
 144   return 1;
 145 }
 146
 147
 148 static int luaB_corunning (lua_State *L) {
 149   int ismain = lua_pushthread(L);
 150   lua_pushboolean(L, ismain);
 151   return 2;
 152 }
 153
 154
 155 static const luaL_Reg co_funcs[] = {
 156   {"create", luaB_cocreate},
 157   {"resume", luaB_coresume},
 158   {"running", luaB_corunning},
 159   {"status", luaB_costatus},
 160   {"wrap", luaB_cowrap},
 161   {"yield", luaB_yield},
 162   {"isyieldable", luaB_yieldable},
 163   {NULL, NULL}
 164 };
 165
 166
 167
 168 LUAMOD_API int luaopen_coroutine (lua_State *L) {
 169   luaL_newlib(L, co_funcs);
 170   return 1;
 171 }
 172