1/*
2** $Id: lfunc.c $
3** Auxiliary functions to manipulate prototypes and closures
4** See Copyright Notice in lua.h
5*/
6
7#define lfunc_c
8#define LUA_CORE
9
10#include "lprefix.h"
11
12
13#include <stddef.h>
14
15#include "lua.h"
16
17#include "ldebug.h"
18#include "ldo.h"
19#include "lfunc.h"
20#include "lgc.h"
21#include "lmem.h"
22#include "lobject.h"
23#include "lstate.h"
24
25
26
27CClosure *luaF_newCclosure (lua_State *L, int nupvals) {
28 GCObject *o = luaC_newobj(L, LUA_VCCL, sizeCclosure(nupvals));
29 CClosure *c = gco2ccl(o);
30 c->nupvalues = cast_byte(nupvals);
31 return c;
32}
33
34
35LClosure *luaF_newLclosure (lua_State *L, int nupvals) {
36 GCObject *o = luaC_newobj(L, LUA_VLCL, sizeLclosure(nupvals));
37 LClosure *c = gco2lcl(o);
38 c->p = NULL;
39 c->nupvalues = cast_byte(nupvals);
40 while (nupvals--) c->upvals[nupvals] = NULL;
41 return c;
42}
43
44
45/*
46** fill a closure with new closed upvalues
47*/
48void luaF_initupvals (lua_State *L, LClosure *cl) {
49 int i;
50 for (i = 0; i < cl->nupvalues; i++) {
51 GCObject *o = luaC_newobj(L, LUA_VUPVAL, sizeof(UpVal));
52 UpVal *uv = gco2upv(o);
53 uv->v.p = &uv->u.value; /* make it closed */
54 setnilvalue(uv->v.p);
55 cl->upvals[i] = uv;
56 luaC_objbarrier(L, cl, uv);
57 }
58}
59
60
61/*
62** Create a new upvalue at the given level, and link it to the list of
63** open upvalues of 'L' after entry 'prev'.
64**/
65static UpVal *newupval (lua_State *L, StkId level, UpVal **prev) {
66 GCObject *o = luaC_newobj(L, LUA_VUPVAL, sizeof(UpVal));
67 UpVal *uv = gco2upv(o);
68 UpVal *next = *prev;
69 uv->v.p = s2v(level); /* current value lives in the stack */
70 uv->u.open.next = next; /* link it to list of open upvalues */
71 uv->u.open.previous = prev;
72 if (next)
73 next->u.open.previous = &uv->u.open.next;
74 *prev = uv;
75 if (!isintwups(L)) { /* thread not in list of threads with upvalues? */
76 L->twups = G(L)->twups; /* link it to the list */
77 G(L)->twups = L;
78 }
79 return uv;
80}
81
82
83/*
84** Find and reuse, or create if it does not exist, an upvalue
85** at the given level.
86*/
87UpVal *luaF_findupval (lua_State *L, StkId level) {
88 UpVal **pp = &L->openupval;
89 UpVal *p;
90 lua_assert(isintwups(L) || L->openupval == NULL);
91 while ((p = *pp) != NULL && uplevel(p) >= level) { /* search for it */
92 lua_assert(!isdead(G(L), p));
93 if (uplevel(p) == level) /* corresponding upvalue? */
94 return p; /* return it */
95 pp = &p->u.open.next;
96 }
97 /* not found: create a new upvalue after 'pp' */
98 return newupval(L, level, pp);
99}
100
101
102/*
103** Call closing method for object 'obj' with error message 'err'. The
104** boolean 'yy' controls whether the call is yieldable.
105** (This function assumes EXTRA_STACK.)
106*/
107static void callclosemethod (lua_State *L, TValue *obj, TValue *err, int yy) {
108 StkId top = L->top.p;
109 const TValue *tm = luaT_gettmbyobj(L, obj, TM_CLOSE);
110 setobj2s(L, top, tm); /* will call metamethod... */
111 setobj2s(L, top + 1, obj); /* with 'self' as the 1st argument */
112 setobj2s(L, top + 2, err); /* and error msg. as 2nd argument */
113 L->top.p = top + 3; /* add function and arguments */
114 if (yy)
115 luaD_call(L, top, 0);
116 else
117 luaD_callnoyield(L, top, 0);
118}
119
120
121/*
122** Check whether object at given level has a close metamethod and raise
123** an error if not.
124*/
125static void checkclosemth (lua_State *L, StkId level) {
126 const TValue *tm = luaT_gettmbyobj(L, s2v(level), TM_CLOSE);
127 if (ttisnil(tm)) { /* no metamethod? */
128 int idx = cast_int(level - L->ci->func.p); /* variable index */
129 const char *vname = luaG_findlocal(L, L->ci, idx, NULL);
130 if (vname == NULL) vname = "?";
131 luaG_runerror(L, "variable '%s' got a non-closable value", vname);
132 }
133}
134
135
136/*
137** Prepare and call a closing method.
138** If status is CLOSEKTOP, the call to the closing method will be pushed
139** at the top of the stack. Otherwise, values can be pushed right after
140** the 'level' of the upvalue being closed, as everything after that
141** won't be used again.
142*/
143static void prepcallclosemth (lua_State *L, StkId level, int status, int yy) {
144 TValue *uv = s2v(level); /* value being closed */
145 TValue *errobj;
146 if (status == CLOSEKTOP)
147 errobj = &G(L)->nilvalue; /* error object is nil */
148 else { /* 'luaD_seterrorobj' will set top to level + 2 */
149 errobj = s2v(level + 1); /* error object goes after 'uv' */
150 luaD_seterrorobj(L, status, level + 1); /* set error object */
151 }
152 callclosemethod(L, uv, errobj, yy);
153}
154
155
156/*
157** Maximum value for deltas in 'tbclist', dependent on the type
158** of delta. (This macro assumes that an 'L' is in scope where it
159** is used.)
160*/
161#define MAXDELTA \
162 ((256ul << ((sizeof(L->stack.p->tbclist.delta) - 1) * 8)) - 1)
163
164
165/*
166** Insert a variable in the list of to-be-closed variables.
167*/
168void luaF_newtbcupval (lua_State *L, StkId level) {
169 lua_assert(level > L->tbclist.p);
170 if (l_isfalse(s2v(level)))
171 return; /* false doesn't need to be closed */
172 checkclosemth(L, level); /* value must have a close method */
173 while (cast_uint(level - L->tbclist.p) > MAXDELTA) {
174 L->tbclist.p += MAXDELTA; /* create a dummy node at maximum delta */
175 L->tbclist.p->tbclist.delta = 0;
176 }
177 level->tbclist.delta = cast(unsigned short, level - L->tbclist.p);
178 L->tbclist.p = level;
179}
180
181
182void luaF_unlinkupval (UpVal *uv) {
183 lua_assert(upisopen(uv));
184 *uv->u.open.previous = uv->u.open.next;
185 if (uv->u.open.next)
186 uv->u.open.next->u.open.previous = uv->u.open.previous;
187}
188
189
190/*
191** Close all upvalues up to the given stack level.
192*/
193void luaF_closeupval (lua_State *L, StkId level) {
194 UpVal *uv;
195 StkId upl; /* stack index pointed by 'uv' */
196 while ((uv = L->openupval) != NULL && (upl = uplevel(uv)) >= level) {
197 TValue *slot = &uv->u.value; /* new position for value */
198 lua_assert(uplevel(uv) < L->top.p);
199 luaF_unlinkupval(uv); /* remove upvalue from 'openupval' list */
200 setobj(L, slot, uv->v.p); /* move value to upvalue slot */
201 uv->v.p = slot; /* now current value lives here */
202 if (!iswhite(uv)) { /* neither white nor dead? */
203 nw2black(uv); /* closed upvalues cannot be gray */
204 luaC_barrier(L, uv, slot);
205 }
206 }
207}
208
209
210/*
211** Remove first element from the tbclist plus its dummy nodes.
212*/
213static void poptbclist (lua_State *L) {
214 StkId tbc = L->tbclist.p;
215 lua_assert(tbc->tbclist.delta > 0); /* first element cannot be dummy */
216 tbc -= tbc->tbclist.delta;
217 while (tbc > L->stack.p && tbc->tbclist.delta == 0)
218 tbc -= MAXDELTA; /* remove dummy nodes */
219 L->tbclist.p = tbc;
220}
221
222
223/*
224** Close all upvalues and to-be-closed variables up to the given stack
225** level. Return restored 'level'.
226*/
227StkId luaF_close (lua_State *L, StkId level, int status, int yy) {
228 ptrdiff_t levelrel = savestack(L, level);
229 luaF_closeupval(L, level); /* first, close the upvalues */
230 while (L->tbclist.p >= level) { /* traverse tbc's down to that level */
231 StkId tbc = L->tbclist.p; /* get variable index */
232 poptbclist(L); /* remove it from list */
233 prepcallclosemth(L, tbc, status, yy); /* close variable */
234 level = restorestack(L, levelrel);
235 }
236 return level;
237}
238
239
240Proto *luaF_newproto (lua_State *L) {
241 GCObject *o = luaC_newobj(L, LUA_VPROTO, sizeof(Proto));
242 Proto *f = gco2p(o);
243 f->k = NULL;
244 f->sizek = 0;
245 f->p = NULL;
246 f->sizep = 0;
247 f->code = NULL;
248 f->sizecode = 0;
249 f->lineinfo = NULL;
250 f->sizelineinfo = 0;
251 f->abslineinfo = NULL;
252 f->sizeabslineinfo = 0;
253 f->upvalues = NULL;
254 f->sizeupvalues = 0;
255 f->numparams = 0;
256 f->is_vararg = 0;
257 f->maxstacksize = 0;
258 f->locvars = NULL;
259 f->sizelocvars = 0;
260 f->linedefined = 0;
261 f->lastlinedefined = 0;
262 f->source = NULL;
263 return f;
264}
265
266
267void luaF_freeproto (lua_State *L, Proto *f) {
268 luaM_freearray(L, f->code, f->sizecode);
269 luaM_freearray(L, f->p, f->sizep);
270 luaM_freearray(L, f->k, f->sizek);
271 luaM_freearray(L, f->lineinfo, f->sizelineinfo);
272 luaM_freearray(L, f->abslineinfo, f->sizeabslineinfo);
273 luaM_freearray(L, f->locvars, f->sizelocvars);
274 luaM_freearray(L, f->upvalues, f->sizeupvalues);
275 luaM_free(L, f);
276}
277
278
279/*
280** Look for n-th local variable at line 'line' in function 'func'.
281** Returns NULL if not found.
282*/
283const char *luaF_getlocalname (const Proto *f, int local_number, int pc) {
284 int i;
285 for (i = 0; i<f->sizelocvars && f->locvars[i].startpc <= pc; i++) {
286 if (pc < f->locvars[i].endpc) { /* is variable active? */
287 local_number--;
288 if (local_number == 0)
289 return getstr(f->locvars[i].varname);
290 }
291 }
292 return NULL; /* not found */
293}
294