ceph/src/lua/src/lcorolib.c

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