1 /*
2 ** $Id: lstate.h,v 2.82.1.1 2013/04/12 18:48:47 roberto Exp $
3 ** Global State
4 ** See Copyright Notice in lua.h
5 */
6 
7 #ifndef lstate_h
8 #define lstate_h
9 
10 #include "lua.h"
11 
12 #include "lobject.h"
13 #include "ltm.h"
14 #include "lzio.h"
15 
16 
17 /*
18 
19 ** Some notes about garbage-collected objects:  All objects in Lua must
20 ** be kept somehow accessible until being freed.
21 **
22 ** Lua keeps most objects linked in list g->allgc. The link uses field
23 ** 'next' of the CommonHeader.
24 **
25 ** Strings are kept in several lists headed by the array g->strt.hash.
26 **
27 ** Open upvalues are not subject to independent garbage collection. They
28 ** are collected together with their respective threads. Lua keeps a
29 ** double-linked list with all open upvalues (g->uvhead) so that it can
30 ** mark objects referred by them. (They are always gray, so they must
31 ** be remarked in the atomic step. Usually their contents would be marked
32 ** when traversing the respective threads, but the thread may already be
33 ** dead, while the upvalue is still accessible through closures.)
34 **
35 ** Objects with finalizers are kept in the list g->finobj.
36 **
37 ** The list g->tobefnz links all objects being finalized.
38 
39 */
40 
41 
42 struct lua_longjmp;  /* defined in ldo.c */
43 
44 
45 
46 /* extra stack space to handle TM calls and some other extras */
47 #define EXTRA_STACK   5
48 
49 
50 #define BASIC_STACK_SIZE        (2*LUA_MINSTACK)
51 
52 
53 /* kinds of Garbage Collection */
54 #define KGC_NORMAL	0
55 #define KGC_EMERGENCY	1	/* gc was forced by an allocation failure */
56 #define KGC_GEN		2	/* generational collection */
57 
58 
59 typedef struct stringtable {
60   GCObject **hash;
61   lu_int32 nuse;  /* number of elements */
62   int size;
63 } stringtable;
64 
65 
66 /*
67 ** information about a call
68 */
69 typedef struct CallInfo {
70   StkId func;  /* function index in the stack */
71   StkId	top;  /* top for this function */
72   struct CallInfo *previous, *next;  /* dynamic call link */
73   short nresults;  /* expected number of results from this function */
74   lu_byte callstatus;
75   ptrdiff_t extra;
76   union {
77     struct {  /* only for Lua functions */
78       StkId base;  /* base for this function */
79       const Instruction *savedpc;
80     } l;
81     struct {  /* only for C functions */
82       int ctx;  /* context info. in case of yields */
83       lua_CFunction k;  /* continuation in case of yields */
84       ptrdiff_t old_errfunc;
85       lu_byte old_allowhook;
86       lu_byte status;
87     } c;
88   } u;
89 } CallInfo;
90 
91 
92 /*
93 ** Bits in CallInfo status
94 */
95 #define CIST_LUA	(1<<0)	/* call is running a Lua function */
96 #define CIST_HOOKED	(1<<1)	/* call is running a debug hook */
97 #define CIST_REENTRY	(1<<2)	/* call is running on same invocation of
98                                    luaV_execute of previous call */
99 #define CIST_YIELDED	(1<<3)	/* call reentered after suspension */
100 #define CIST_YPCALL	(1<<4)	/* call is a yieldable protected call */
101 #define CIST_STAT	(1<<5)	/* call has an error status (pcall) */
102 #define CIST_TAIL	(1<<6)	/* call was tail called */
103 #define CIST_HOOKYIELD	(1<<7)	/* last hook called yielded */
104 
105 
106 #define isLua(ci)	((ci)->callstatus & CIST_LUA)
107 
108 
109 /*
110 ** `global state', shared by all threads of this state
111 */
112 typedef struct global_State {
113   lua_Alloc frealloc;  /* function to reallocate memory */
114   void *ud;         /* auxiliary data to `frealloc' */
115   lu_mem totalbytes;  /* number of bytes currently allocated - GCdebt */
116   l_mem GCdebt;  /* bytes allocated not yet compensated by the collector */
117   lu_mem GCmemtrav;  /* memory traversed by the GC */
118   lu_mem GCestimate;  /* an estimate of the non-garbage memory in use */
119   stringtable strt;  /* hash table for strings */
120   TValue l_registry;
121   unsigned int seed;  /* randomized seed for hashes */
122   lu_byte currentwhite;
123   lu_byte gcstate;  /* state of garbage collector */
124   lu_byte gckind;  /* kind of GC running */
125   lu_byte gcrunning;  /* true if GC is running */
126   int sweepstrgc;  /* position of sweep in `strt' */
127   GCObject *allgc;  /* list of all collectable objects */
128   GCObject *finobj;  /* list of collectable objects with finalizers */
129   GCObject **sweepgc;  /* current position of sweep in list 'allgc' */
130   GCObject **sweepfin;  /* current position of sweep in list 'finobj' */
131   GCObject *gray;  /* list of gray objects */
132   GCObject *grayagain;  /* list of objects to be traversed atomically */
133   GCObject *weak;  /* list of tables with weak values */
134   GCObject *ephemeron;  /* list of ephemeron tables (weak keys) */
135   GCObject *allweak;  /* list of all-weak tables */
136   GCObject *tobefnz;  /* list of userdata to be GC */
137   UpVal uvhead;  /* head of double-linked list of all open upvalues */
138   Mbuffer buff;  /* temporary buffer for string concatenation */
139   int gcpause;  /* size of pause between successive GCs */
140   int gcmajorinc;  /* pause between major collections (only in gen. mode) */
141   int gcstepmul;  /* GC `granularity' */
142   lua_CFunction panic;  /* to be called in unprotected errors */
143   struct lua_State *mainthread;
144   const lua_Number *version;  /* pointer to version number */
145   TString *memerrmsg;  /* memory-error message */
146   TString *tmname[TM_N];  /* array with tag-method names */
147   struct Table *mt[LUA_NUMTAGS];  /* metatables for basic types */
148 } global_State;
149 
150 
151 /*
152 ** `per thread' state
153 */
154 struct lua_State {
155   CommonHeader;
156   lu_byte status;
157   StkId top;  /* first free slot in the stack */
158   global_State *l_G;
159   CallInfo *ci;  /* call info for current function */
160   const Instruction *oldpc;  /* last pc traced */
161   StkId stack_last;  /* last free slot in the stack */
162   StkId stack;  /* stack base */
163   int stacksize;
164   unsigned short nny;  /* number of non-yieldable calls in stack */
165   unsigned short nCcalls;  /* number of nested C calls */
166   lu_byte hookmask;
167   lu_byte allowhook;
168   int basehookcount;
169   int hookcount;
170   lua_Hook hook;
171   GCObject *openupval;  /* list of open upvalues in this stack */
172   GCObject *gclist;
173   struct lua_longjmp *errorJmp;  /* current error recover point */
174   ptrdiff_t errfunc;  /* current error handling function (stack index) */
175   CallInfo base_ci;  /* CallInfo for first level (C calling Lua) */
176 };
177 
178 
179 #define G(L)	(L->l_G)
180 
181 
182 /*
183 ** Union of all collectable objects
184 */
185 union GCObject {
186   GCheader gch;  /* common header */
187   union TString ts;
188   union Udata u;
189   union Closure cl;
190   struct Table h;
191   struct Proto p;
192   struct UpVal uv;
193   struct lua_State th;  /* thread */
194 };
195 
196 
197 #define gch(o)		(&(o)->gch)
198 
199 /* macros to convert a GCObject into a specific value */
200 #define rawgco2ts(o)  \
201 	check_exp(novariant((o)->gch.tt) == LUA_TSTRING, &((o)->ts))
202 #define gco2ts(o)	(&rawgco2ts(o)->tsv)
203 #define rawgco2u(o)	check_exp((o)->gch.tt == LUA_TUSERDATA, &((o)->u))
204 #define gco2u(o)	(&rawgco2u(o)->uv)
205 #define gco2lcl(o)	check_exp((o)->gch.tt == LUA_TLCL, &((o)->cl.l))
206 #define gco2ccl(o)	check_exp((o)->gch.tt == LUA_TCCL, &((o)->cl.c))
207 #define gco2cl(o)  \
208 	check_exp(novariant((o)->gch.tt) == LUA_TFUNCTION, &((o)->cl))
209 #define gco2t(o)	check_exp((o)->gch.tt == LUA_TTABLE, &((o)->h))
210 #define gco2p(o)	check_exp((o)->gch.tt == LUA_TPROTO, &((o)->p))
211 #define gco2uv(o)	check_exp((o)->gch.tt == LUA_TUPVAL, &((o)->uv))
212 #define gco2th(o)	check_exp((o)->gch.tt == LUA_TTHREAD, &((o)->th))
213 
214 /* macro to convert any Lua object into a GCObject */
215 #define obj2gco(v)	(cast(GCObject *, (v)))
216 
217 
218 /* actual number of total bytes allocated */
219 #define gettotalbytes(g)	((g)->totalbytes + (g)->GCdebt)
220 
221 LUAI_FUNC void luaE_setdebt (global_State *g, l_mem debt);
222 LUAI_FUNC void luaE_freethread (lua_State *L, lua_State *L1);
223 LUAI_FUNC CallInfo *luaE_extendCI (lua_State *L);
224 LUAI_FUNC void luaE_freeCI (lua_State *L);
225 
226 
227 #endif
228 
229