summaryrefslogtreecommitdiff
path: root/libs/liblua/src/lcorolib.c
blob: 2303429e7bb3d6e37bab6f8587994d486b037c39 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
/*
** $Id: lcorolib.c,v 1.10 2016/04/11 19:19:55 roberto Exp $
** Coroutine Library
** See Copyright Notice in lua.h
*/

#define lcorolib_c
#define LUA_LIB

#include "lprefix.h"


#include <stdlib.h>

#include "lua.h"

#include "lauxlib.h"
#include "lualib.h"


static lua_State *getco (lua_State *L) {
  lua_State *co = lua_tothread(L, 1);
  luaL_argcheck(L, co, 1, "thread expected");
  return co;
}


static int auxresume (lua_State *L, lua_State *co, int narg) {
  int status;
  if (!lua_checkstack(co, narg)) {
    lua_pushliteral(L, "too many arguments to resume");
    return -1;  /* error flag */
  }
  if (lua_status(co) == LUA_OK && lua_gettop(co) == 0) {
    lua_pushliteral(L, "cannot resume dead coroutine");
    return -1;  /* error flag */
  }
  lua_xmove(L, co, narg);
  status = lua_resume(co, L, narg);
  if (status == LUA_OK || status == LUA_YIELD) {
    int nres = lua_gettop(co);
    if (!lua_checkstack(L, nres + 1)) {
      lua_pop(co, nres);  /* remove results anyway */
      lua_pushliteral(L, "too many results to resume");
      return -1;  /* error flag */
    }
    lua_xmove(co, L, nres);  /* move yielded values */
    return nres;
  }
  else {
    lua_xmove(co, L, 1);  /* move error message */
    return -1;  /* error flag */
  }
}


static int luaB_coresume (lua_State *L) {
  lua_State *co = getco(L);
  int r;
  r = auxresume(L, co, lua_gettop(L) - 1);
  if (r < 0) {
    lua_pushboolean(L, 0);
    lua_insert(L, -2);
    return 2;  /* return false + error message */
  }
  else {
    lua_pushboolean(L, 1);
    lua_insert(L, -(r + 1));
    return r + 1;  /* return true + 'resume' returns */
  }
}


static int luaB_auxwrap (lua_State *L) {
  lua_State *co = lua_tothread(L, lua_upvalueindex(1));
  int r = auxresume(L, co, lua_gettop(L));
  if (r < 0) {
    if (lua_type(L, -1) == LUA_TSTRING) {  /* error object is a string? */
      luaL_where(L, 1);  /* add extra info */
      lua_insert(L, -2);
      lua_concat(L, 2);
    }
    return lua_error(L);  /* propagate error */
  }
  return r;
}


static int luaB_cocreate (lua_State *L) {
  lua_State *NL;
  luaL_checktype(L, 1, LUA_TFUNCTION);
  NL = lua_newthread(L);
  lua_pushvalue(L, 1);  /* move function to top */
  lua_xmove(L, NL, 1);  /* move function from L to NL */
  return 1;
}


static int luaB_cowrap (lua_State *L) {
  luaB_cocreate(L);
  lua_pushcclosure(L, luaB_auxwrap, 1);
  return 1;
}


static int luaB_yield (lua_State *L) {
  return lua_yield(L, lua_gettop(L));
}


static int luaB_costatus (lua_State *L) {
  lua_State *co = getco(L);
  if (L == co) lua_pushliteral(L, "running");
  else {
    switch (lua_status(co)) {
      case LUA_YIELD:
        lua_pushliteral(L, "suspended");
        break;
      case LUA_OK: {
        lua_Debug ar;
        if (lua_getstack(co, 0, &ar) > 0)  /* does it have frames? */
          lua_pushliteral(L, "normal");  /* it is running */
        else if (lua_gettop(co) == 0)
            lua_pushliteral(L, "dead");
        else
          lua_pushliteral(L, "suspended");  /* initial state */
        break;
      }
      default:  /* some error occurred */
        lua_pushliteral(L, "dead");
        break;
    }
  }
  return 1;
}


static int luaB_yieldable (lua_State *L) {
  lua_pushboolean(L, lua_isyieldable(L));
  return 1;
}


static int luaB_corunning (lua_State *L) {
  int ismain = lua_pushthread(L);
  lua_pushboolean(L, ismain);
  return 2;
}


static const luaL_Reg co_funcs[] = {
  {"create", luaB_cocreate},
  {"resume", luaB_coresume},
  {"running", luaB_corunning},
  {"status", luaB_costatus},
  {"wrap", luaB_cowrap},
  {"yield", luaB_yield},
  {"isyieldable", luaB_yieldable},
  {NULL, NULL}
};



LUAMOD_API int luaopen_coroutine (lua_State *L) {
  luaL_newlib(L, co_funcs);
  return 1;
}