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