1/*
2** $Id: lstate.h,v 2.82 2012/07/02 13:37:04 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
42struct 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
59typedef 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*/
69typedef 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*/
112typedef 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*/
154struct 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*/
185union 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
221LUAI_FUNC void luaE_setdebt (global_State *g, l_mem debt);
222LUAI_FUNC void luaE_freethread (lua_State *L, lua_State *L1);
223LUAI_FUNC CallInfo *luaE_extendCI (lua_State *L);
224LUAI_FUNC void luaE_freeCI (lua_State *L);
225
226
227#endif
228
229