1 /* $NetBSD: lcorolib.c,v 1.2 2015/02/02 14:03:05 lneto Exp $ */
2
3 /*
4 ** Id: lcorolib.c,v 1.9 2014/11/02 19:19:04 roberto Exp
5 ** Coroutine Library
6 ** See Copyright Notice in lua.h
7 */
8
9 #define lcorolib_c
10 #define LUA_LIB
11
12 #include "lprefix.h"
13
14
15 #ifndef _KERNEL
16 #include <stdlib.h>
17 #endif
18
19 #include "lua.h"
20
21 #include "lauxlib.h"
22 #include "lualib.h"
23
24
getco(lua_State * L)25 static lua_State *getco (lua_State *L) {
26 lua_State *co = lua_tothread(L, 1);
27 luaL_argcheck(L, co, 1, "thread expected");
28 return co;
29 }
30
31
auxresume(lua_State * L,lua_State * co,int narg)32 static int auxresume (lua_State *L, lua_State *co, int narg) {
33 int status;
34 if (!lua_checkstack(co, narg)) {
35 lua_pushliteral(L, "too many arguments to resume");
36 return -1; /* error flag */
37 }
38 if (lua_status(co) == LUA_OK && lua_gettop(co) == 0) {
39 lua_pushliteral(L, "cannot resume dead coroutine");
40 return -1; /* error flag */
41 }
42 lua_xmove(L, co, narg);
43 status = lua_resume(co, L, narg);
44 if (status == LUA_OK || status == LUA_YIELD) {
45 int nres = lua_gettop(co);
46 if (!lua_checkstack(L, nres + 1)) {
47 lua_pop(co, nres); /* remove results anyway */
48 lua_pushliteral(L, "too many results to resume");
49 return -1; /* error flag */
50 }
51 lua_xmove(co, L, nres); /* move yielded values */
52 return nres;
53 }
54 else {
55 lua_xmove(co, L, 1); /* move error message */
56 return -1; /* error flag */
57 }
58 }
59
60
luaB_coresume(lua_State * L)61 static int luaB_coresume (lua_State *L) {
62 lua_State *co = getco(L);
63 int r;
64 r = auxresume(L, co, lua_gettop(L) - 1);
65 if (r < 0) {
66 lua_pushboolean(L, 0);
67 lua_insert(L, -2);
68 return 2; /* return false + error message */
69 }
70 else {
71 lua_pushboolean(L, 1);
72 lua_insert(L, -(r + 1));
73 return r + 1; /* return true + 'resume' returns */
74 }
75 }
76
77
luaB_auxwrap(lua_State * L)78 static int luaB_auxwrap (lua_State *L) {
79 lua_State *co = lua_tothread(L, lua_upvalueindex(1));
80 int r = auxresume(L, co, lua_gettop(L));
81 if (r < 0) {
82 if (lua_isstring(L, -1)) { /* error object is a string? */
83 luaL_where(L, 1); /* add extra info */
84 lua_insert(L, -2);
85 lua_concat(L, 2);
86 }
87 return lua_error(L); /* propagate error */
88 }
89 return r;
90 }
91
92
luaB_cocreate(lua_State * L)93 static int luaB_cocreate (lua_State *L) {
94 lua_State *NL;
95 luaL_checktype(L, 1, LUA_TFUNCTION);
96 NL = lua_newthread(L);
97 lua_pushvalue(L, 1); /* move function to top */
98 lua_xmove(L, NL, 1); /* move function from L to NL */
99 return 1;
100 }
101
102
luaB_cowrap(lua_State * L)103 static int luaB_cowrap (lua_State *L) {
104 luaB_cocreate(L);
105 lua_pushcclosure(L, luaB_auxwrap, 1);
106 return 1;
107 }
108
109
luaB_yield(lua_State * L)110 static int luaB_yield (lua_State *L) {
111 return lua_yield(L, lua_gettop(L));
112 }
113
114
luaB_costatus(lua_State * L)115 static int luaB_costatus (lua_State *L) {
116 lua_State *co = getco(L);
117 if (L == co) lua_pushliteral(L, "running");
118 else {
119 switch (lua_status(co)) {
120 case LUA_YIELD:
121 lua_pushliteral(L, "suspended");
122 break;
123 case LUA_OK: {
124 lua_Debug ar;
125 if (lua_getstack(co, 0, &ar) > 0) /* does it have frames? */
126 lua_pushliteral(L, "normal"); /* it is running */
127 else if (lua_gettop(co) == 0)
128 lua_pushliteral(L, "dead");
129 else
130 lua_pushliteral(L, "suspended"); /* initial state */
131 break;
132 }
133 default: /* some error occurred */
134 lua_pushliteral(L, "dead");
135 break;
136 }
137 }
138 return 1;
139 }
140
141
luaB_yieldable(lua_State * L)142 static int luaB_yieldable (lua_State *L) {
143 lua_pushboolean(L, lua_isyieldable(L));
144 return 1;
145 }
146
147
luaB_corunning(lua_State * L)148 static int luaB_corunning (lua_State *L) {
149 int ismain = lua_pushthread(L);
150 lua_pushboolean(L, ismain);
151 return 2;
152 }
153
154
155 static const luaL_Reg co_funcs[] = {
156 {"create", luaB_cocreate},
157 {"resume", luaB_coresume},
158 {"running", luaB_corunning},
159 {"status", luaB_costatus},
160 {"wrap", luaB_cowrap},
161 {"yield", luaB_yield},
162 {"isyieldable", luaB_yieldable},
163 {NULL, NULL}
164 };
165
166
167
luaopen_coroutine(lua_State * L)168 LUAMOD_API int luaopen_coroutine (lua_State *L) {
169 luaL_newlib(L, co_funcs);
170 return 1;
171 }
172
173