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 = &uv->u.value; /* make it closed */
54 setnilvalue(uv->v);
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, int tbc, 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 = s2v(level); /* current value lives in the stack */
70 uv->tbc = tbc;
71 uv->u.open.next = next; /* link it to list of open upvalues */
72 uv->u.open.previous = prev;
73 if (next)
74 next->u.open.previous = &uv->u.open.next;
75 *prev = uv;
76 if (!isintwups(L)) { /* thread not in list of threads with upvalues? */
77 L->twups = G(L)->twups; /* link it to the list */
78 G(L)->twups = L;
79 }
80 return uv;
81}
82
83
84/*
85** Find and reuse, or create if it does not exist, an upvalue
86** at the given level.
87*/
88UpVal *luaF_findupval (lua_State *L, StkId level) {
89 UpVal **pp = &L->openupval;
90 UpVal *p;
91 lua_assert(isintwups(L) || L->openupval == NULL);
92 while ((p = *pp) != NULL && uplevel(p) >= level) { /* search for it */
93 lua_assert(!isdead(G(L), p));
94 if (uplevel(p) == level) /* corresponding upvalue? */
95 return p; /* return it */
96 pp = &p->u.open.next;
97 }
98 /* not found: create a new upvalue after 'pp' */
99 return newupval(L, 0, level, pp);
100}
101
102
103/*
104** Call closing method for object 'obj' with error message 'err'. The
105** boolean 'yy' controls whether the call is yieldable.
106** (This function assumes EXTRA_STACK.)
107*/
108static void callclosemethod (lua_State *L, TValue *obj, TValue *err, int yy) {
109 StkId top = L->top;
110 const TValue *tm = luaT_gettmbyobj(L, obj, TM_CLOSE);
111 setobj2s(L, top, tm); /* will call metamethod... */
112 setobj2s(L, top + 1, obj); /* with 'self' as the 1st argument */
113 setobj2s(L, top + 2, err); /* and error msg. as 2nd argument */
114 L->top = top + 3; /* add function and arguments */
115 if (yy)
116 luaD_call(L, top, 0);
117 else
118 luaD_callnoyield(L, top, 0);
119}
120
121
122/*
123** Check whether object at given level has a close metamethod and raise
124** an error if not.
125*/
126static void checkclosemth (lua_State *L, StkId level) {
127 const TValue *tm = luaT_gettmbyobj(L, s2v(level), TM_CLOSE);
128 if (ttisnil(tm)) { /* no metamethod? */
129 int idx = cast_int(level - L->ci->func); /* variable index */
130 const char *vname = luaG_findlocal(L, L->ci, idx, NULL);
131 if (vname == NULL) vname = "?";
132 luaG_runerror(L, "variable '%s' got a non-closable value", vname);
133 }
134}
135
136
137/*
138** Prepare and call a closing method.
139** If status is CLOSEKTOP, the call to the closing method will be pushed
140** at the top of the stack. Otherwise, values can be pushed right after
141** the 'level' of the upvalue being closed, as everything after that
142** won't be used again.
143*/
144static void prepcallclosemth (lua_State *L, StkId level, int status, int yy) {
145 TValue *uv = s2v(level); /* value being closed */
146 TValue *errobj;
147 if (status == CLOSEKTOP)
148 errobj = &G(L)->nilvalue; /* error object is nil */
149 else { /* 'luaD_seterrorobj' will set top to level + 2 */
150 errobj = s2v(level + 1); /* error object goes after 'uv' */
151 luaD_seterrorobj(L, status, level + 1); /* set error object */
152 }
153 callclosemethod(L, uv, errobj, yy);
154}
155
156
157/*
158** Maximum value for deltas in 'tbclist', dependent on the type
159** of delta. (This macro assumes that an 'L' is in scope where it
160** is used.)
161*/
162#define MAXDELTA \
163 ((256ul << ((sizeof(L->stack->tbclist.delta) - 1) * 8)) - 1)
164
165
166/*
167** Insert a variable in the list of to-be-closed variables.
168*/
169void luaF_newtbcupval (lua_State *L, StkId level) {
170 lua_assert(level > L->tbclist);
171 if (l_isfalse(s2v(level)))
172 return; /* false doesn't need to be closed */
173 checkclosemth(L, level); /* value must have a close method */
174 while (cast_uint(level - L->tbclist) > MAXDELTA) {
175 L->tbclist += MAXDELTA; /* create a dummy node at maximum delta */
176 L->tbclist->tbclist.delta = 0;
177 }
178 level->tbclist.delta = cast(unsigned short, level - L->tbclist);
179 L->tbclist = level;
180}
181
182
183void luaF_unlinkupval (UpVal *uv) {
184 lua_assert(upisopen(uv));
185 *uv->u.open.previous = uv->u.open.next;
186 if (uv->u.open.next)
187 uv->u.open.next->u.open.previous = uv->u.open.previous;
188}
189
190
191/*
192** Close all upvalues up to the given stack level.
193*/
194void luaF_closeupval (lua_State *L, StkId level) {
195 UpVal *uv;
196 StkId upl; /* stack index pointed by 'uv' */
197 while ((uv = L->openupval) != NULL && (upl = uplevel(uv)) >= level) {
198 TValue *slot = &uv->u.value; /* new position for value */
199 lua_assert(uplevel(uv) < L->top);
200 luaF_unlinkupval(uv); /* remove upvalue from 'openupval' list */
201 setobj(L, slot, uv->v); /* move value to upvalue slot */
202 uv->v = slot; /* now current value lives here */
203 if (!iswhite(uv)) { /* neither white nor dead? */
204 nw2black(uv); /* closed upvalues cannot be gray */
205 luaC_barrier(L, uv, slot);
206 }
207 }
208}
209
210
211/*
212** Remove firt element from the tbclist plus its dummy nodes.
213*/
214static void poptbclist (lua_State *L) {
215 StkId tbc = L->tbclist;
216 lua_assert(tbc->tbclist.delta > 0); /* first element cannot be dummy */
217 tbc -= tbc->tbclist.delta;
218 while (tbc > L->stack && tbc->tbclist.delta == 0)
219 tbc -= MAXDELTA; /* remove dummy nodes */
220 L->tbclist = tbc;
221}
222
223
224/*
225** Close all upvalues and to-be-closed variables up to the given stack
226** level.
227*/
228void luaF_close (lua_State *L, StkId level, int status, int yy) {
229 ptrdiff_t levelrel = savestack(L, level);
230 luaF_closeupval(L, level); /* first, close the upvalues */
231 while (L->tbclist >= level) { /* traverse tbc's down to that level */
232 StkId tbc = L->tbclist; /* get variable index */
233 poptbclist(L); /* remove it from list */
234 prepcallclosemth(L, tbc, status, yy); /* close variable */
235 level = restorestack(L, levelrel);
236 }
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
295