• Home
  • Line#
  • Scopes#
  • Navigate#
  • Raw
  • Download
1 /*
2 ** $Id: lcorolib.c,v 1.10.1.1 2017/04/19 17:20:42 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 
getco(lua_State * L)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 
auxresume(lua_State * L,lua_State * co,int narg)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 
luaB_coresume(lua_State * L)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 
luaB_auxwrap(lua_State * L)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_type(L, -1) == LUA_TSTRING) {  /* 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 
luaB_cocreate(lua_State * L)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 
luaB_cowrap(lua_State * L)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 
luaB_yield(lua_State * L)106 static int luaB_yield (lua_State *L) {
107   return lua_yield(L, lua_gettop(L));
108 }
109 
110 
luaB_costatus(lua_State * L)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 
luaB_yieldable(lua_State * L)138 static int luaB_yieldable (lua_State *L) {
139   lua_pushboolean(L, lua_isyieldable(L));
140   return 1;
141 }
142 
143 
luaB_corunning(lua_State * L)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 
luaopen_coroutine(lua_State * L)164 LUAMOD_API int luaopen_coroutine (lua_State *L) {
165   luaL_newlib(L, co_funcs);
166   return 1;
167 }
168 
169