The Battle for Wesnoth  1.15.12+dev
lcorolib.cpp
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1 /*
2 ** $Id: lcorolib.c $
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 
21 static lua_State *getco (lua_State *L) {
22  lua_State *co = lua_tothread(L, 1);
23  luaL_argexpected(L, co, 1, "thread");
24  return co;
25 }
26 
27 
28 /*
29 ** Resumes a coroutine. Returns the number of results for non-error
30 ** cases or -1 for errors.
31 */
32 static int auxresume (lua_State *L, lua_State *co, int narg) {
33  int status, nres;
34  if (!lua_checkstack(co, narg)) {
35  lua_pushliteral(L, "too many arguments to resume");
36  return -1; /* error flag */
37  }
38  lua_xmove(L, co, narg);
39  status = lua_resume(co, L, narg, &nres);
40  if (status == LUA_OK || status == LUA_YIELD) {
41  if (!lua_checkstack(L, nres + 1)) {
42  lua_pop(co, nres); /* remove results anyway */
43  lua_pushliteral(L, "too many results to resume");
44  return -1; /* error flag */
45  }
46  lua_xmove(co, L, nres); /* move yielded values */
47  return nres;
48  }
49  else {
50  lua_xmove(co, L, 1); /* move error message */
51  return -1; /* error flag */
52  }
53 }
54 
55 
56 static int luaB_coresume (lua_State *L) {
57  lua_State *co = getco(L);
58  int r;
59  r = auxresume(L, co, lua_gettop(L) - 1);
60  if (r < 0) {
61  lua_pushboolean(L, 0);
62  lua_insert(L, -2);
63  return 2; /* return false + error message */
64  }
65  else {
66  lua_pushboolean(L, 1);
67  lua_insert(L, -(r + 1));
68  return r + 1; /* return true + 'resume' returns */
69  }
70 }
71 
72 
73 static int luaB_auxwrap (lua_State *L) {
75  int r = auxresume(L, co, lua_gettop(L));
76  if (r < 0) { /* error? */
77  int stat = lua_status(co);
78  if (stat != LUA_OK && stat != LUA_YIELD) /* error in the coroutine? */
79  lua_resetthread(co); /* close its tbc variables */
80  if (stat != LUA_ERRMEM && /* not a memory error and ... */
81  lua_type(L, -1) == LUA_TSTRING) { /* ... error object is a string? */
82  luaL_where(L, 1); /* add extra info, if available */
83  lua_insert(L, -2);
84  lua_concat(L, 2);
85  }
86  return lua_error(L); /* propagate error */
87  }
88  return r;
89 }
90 
91 
92 static int luaB_cocreate (lua_State *L) {
93  lua_State *NL;
95  NL = lua_newthread(L);
96  lua_pushvalue(L, 1); /* move function to top */
97  lua_xmove(L, NL, 1); /* move function from L to NL */
98  return 1;
99 }
100 
101 
102 static int luaB_cowrap (lua_State *L) {
103  luaB_cocreate(L);
105  return 1;
106 }
107 
108 
109 static int luaB_yield (lua_State *L) {
110  return lua_yield(L, lua_gettop(L));
111 }
112 
113 
114 #define COS_RUN 0
115 #define COS_DEAD 1
116 #define COS_YIELD 2
117 #define COS_NORM 3
118 
119 
120 static const char *const statname[] =
121  {"running", "dead", "suspended", "normal"};
122 
123 
124 static int auxstatus (lua_State *L, lua_State *co) {
125  if (L == co) return COS_RUN;
126  else {
127  switch (lua_status(co)) {
128  case LUA_YIELD:
129  return COS_YIELD;
130  case LUA_OK: {
131  lua_Debug ar;
132  if (lua_getstack(co, 0, &ar)) /* does it have frames? */
133  return COS_NORM; /* it is running */
134  else if (lua_gettop(co) == 0)
135  return COS_DEAD;
136  else
137  return COS_YIELD; /* initial state */
138  }
139  default: /* some error occurred */
140  return COS_DEAD;
141  }
142  }
143 }
144 
145 
146 static int luaB_costatus (lua_State *L) {
147  lua_State *co = getco(L);
148  lua_pushstring(L, statname[auxstatus(L, co)]);
149  return 1;
150 }
151 
152 
153 static int luaB_yieldable (lua_State *L) {
154  lua_State *co = lua_isnone(L, 1) ? L : getco(L);
156  return 1;
157 }
158 
159 
160 static int luaB_corunning (lua_State *L) {
161  int ismain = lua_pushthread(L);
162  lua_pushboolean(L, ismain);
163  return 2;
164 }
165 
166 
167 static int luaB_close (lua_State *L) {
168  lua_State *co = getco(L);
169  int status = auxstatus(L, co);
170  switch (status) {
171  case COS_DEAD: case COS_YIELD: {
172  status = lua_resetthread(co);
173  if (status == LUA_OK) {
174  lua_pushboolean(L, 1);
175  return 1;
176  }
177  else {
178  lua_pushboolean(L, 0);
179  lua_xmove(co, L, 1); /* copy error message */
180  return 2;
181  }
182  }
183  default: /* normal or running coroutine */
184  return luaL_error(L, "cannot close a %s coroutine", statname[status]);
185  }
186 }
187 
188 
189 static const luaL_Reg co_funcs[] = {
190  {"create", luaB_cocreate},
191  {"resume", luaB_coresume},
192  {"running", luaB_corunning},
193  {"status", luaB_costatus},
194  {"wrap", luaB_cowrap},
195  {"yield", luaB_yield},
196  {"isyieldable", luaB_yieldable},
197  {"close", luaB_close},
198  {NULL, NULL}
199 };
200 
201 
202 
204  luaL_newlib(L, co_funcs);
205  return 1;
206 }
207 
static int auxstatus(lua_State *L, lua_State *co)
Definition: lcorolib.cpp:124
Definition: lua.h:469
#define COS_RUN
Definition: lcorolib.cpp:114
#define lua_isnone(L, n)
Definition: lua.h:378
LUA_API int lua_type(lua_State *L, int idx)
Definition: lapi.cpp:260
LUA_API void lua_pushboolean(lua_State *L, int b)
Definition: lapi.cpp:581
#define luaL_argexpected(L, cond, arg, tname)
Definition: lauxlib.h:135
LUA_API int lua_gettop(lua_State *L)
Definition: lapi.cpp:168
static int auxresume(lua_State *L, lua_State *co, int narg)
Definition: lcorolib.cpp:32
LUA_API int lua_checkstack(lua_State *L, int n)
Definition: lapi.cpp:98
#define LUA_TFUNCTION
Definition: lua.h:71
static int luaB_cocreate(lua_State *L)
Definition: lcorolib.cpp:92
LUA_API void lua_pushcclosure(lua_State *L, lua_CFunction fn, int n)
Definition: lapi.cpp:555
LUA_API int lua_getstack(lua_State *L, int level, lua_Debug *ar)
Definition: ldebug.cpp:164
#define lua_pop(L, n)
Definition: lua.h:364
static const char *const statname[]
Definition: lcorolib.cpp:120
#define COS_NORM
Definition: lcorolib.cpp:117
#define lua_upvalueindex(i)
Definition: lua.h:45
#define LUA_TSTRING
Definition: lua.h:69
LUAMOD_API int luaopen_coroutine(lua_State *L)
Definition: lcorolib.cpp:203
#define LUA_YIELD
Definition: lua.h:50
static int luaB_yield(lua_State *L)
Definition: lcorolib.cpp:109
LUA_API lua_State * lua_tothread(lua_State *L, int idx)
Definition: lapi.cpp:438
LUALIB_API void luaL_where(lua_State *L, int level)
Definition: lauxlib.cpp:216
static int luaB_auxwrap(lua_State *L)
Definition: lcorolib.cpp:73
static int luaB_cowrap(lua_State *L)
Definition: lcorolib.cpp:102
#define COS_DEAD
Definition: lcorolib.cpp:115
LUA_API int lua_status(lua_State *L)
Definition: lapi.cpp:1093
static int luaB_costatus(lua_State *L)
Definition: lcorolib.cpp:146
LUA_API int lua_resume(lua_State *L, lua_State *from, int nargs, int *nresults)
Definition: ldo.cpp:701
static int luaB_close(lua_State *L)
Definition: lcorolib.cpp:167
#define lua_pushliteral(L, s)
Definition: lua.h:381
LUA_API int lua_pushthread(lua_State *L)
Definition: lapi.cpp:600
LUALIB_API void luaL_checktype(lua_State *L, int arg, int t)
Definition: lauxlib.cpp:390
LUA_API void lua_xmove(lua_State *from, lua_State *to, int n)
Definition: lapi.cpp:120
#define LUAMOD_API
Definition: luaconf.h:286
int lua_resetthread(lua_State *L)
Definition: lstate.cpp:327
#define lua_yield(L, n)
Definition: lua.h:305
static int luaB_coresume(lua_State *L)
Definition: lcorolib.cpp:56
LUA_API void lua_pushvalue(lua_State *L, int idx)
Definition: lapi.cpp:246
#define LUA_ERRMEM
Definition: lua.h:53
static const luaL_Reg co_funcs[]
Definition: lcorolib.cpp:189
#define luaL_newlib(L, l)
Definition: lauxlib.h:129
LUALIB_API int luaL_error(lua_State *L, const char *fmt,...)
Definition: lauxlib.cpp:234
LUA_API int lua_isyieldable(lua_State *L)
Definition: ldo.cpp:736
static int luaB_corunning(lua_State *L)
Definition: lcorolib.cpp:160
LUA_API int lua_error(lua_State *L)
Definition: lapi.cpp:1205
#define LUA_OK
Definition: lua.h:49
LUA_API void lua_concat(lua_State *L, int n)
Definition: lapi.cpp:1253
#define lua_insert(L, idx)
Definition: lua.h:389
LUA_API lua_State * lua_newthread(lua_State *L)
Definition: lstate.cpp:285
static int luaB_yieldable(lua_State *L)
Definition: lcorolib.cpp:153
#define COS_YIELD
Definition: lcorolib.cpp:116
static lua_State * getco(lua_State *L)
Definition: lcorolib.cpp:21
LUA_API const char * lua_pushstring(lua_State *L, const char *s)
Definition: lapi.cpp:514