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
21static 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
28static 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
57static 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
74static 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
89static 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
99static int luaB_cowrap (lua_State *L) {
100 luaB_cocreate(L);
101 lua_pushcclosure(L, luaB_auxwrap, 1);
102 return 1;
103}
104
105
106static int luaB_yield (lua_State *L) {
107 return lua_yield(L, lua_gettop(L));
108}
109
110
111static 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
138static int luaB_yieldable (lua_State *L) {
139 lua_pushboolean(L, lua_isyieldable(L));
140 return 1;
141}
142
143
144static int luaB_corunning (lua_State *L) {
145 int ismain = lua_pushthread(L);
146 lua_pushboolean(L, ismain);
147 return 2;
148}
149
150
151static 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
164LUAMOD_API int luaopen_coroutine (lua_State *L) {
165 luaL_newlib(L, co_funcs);
166 return 1;
167}
168
169