From beee01b170c5fea9ed4527b28b9221d2df1baaba Mon Sep 17 00:00:00 2001
From: Roberto Ierusalimschy <roberto@inf.puc-rio.br>
Date: Tue, 17 Apr 2001 14:35:54 -0300
Subject: re-implementation of refs through weak tables
---
lapi.c | 76 +++++++++++++++++++++++++++++++++++++++-------------------------
lgc.c | 35 +++---------------------------
lstate.c | 25 ++++-----------------
lstate.h | 22 +++----------------
ltests.c | 15 ++++++++++---
lua.h | 25 +++++++++++----------
6 files changed, 81 insertions(+), 117 deletions(-)
diff --git a/lapi.c b/lapi.c
index 243087fe..c715301d 100644
--- a/lapi.c
+++ b/lapi.c
@@ -1,5 +1,5 @@
/*
-** $Id: lapi.c,v 1.138 2001/04/11 14:42:41 roberto Exp roberto $
+** $Id: lapi.c,v 1.139 2001/04/11 18:39:37 roberto Exp roberto $
** Lua API
** See Copyright Notice in lua.h
*/
@@ -417,21 +417,18 @@ LUA_API void lua_getglobals (lua_State *L) {
LUA_API int lua_getref (lua_State *L, int ref) {
- int status = 1;
+ int status;
lua_lock(L);
if (ref == LUA_REFNIL) {
setnilvalue(L->top);
- api_incr_top(L);
+ status = 1;
}
else {
- api_check(L, 0 <= ref && ref < G(L)->nref);
- if (G(L)->refArray[ref].st != LOCK && G(L)->refArray[ref].st != HOLD)
- status = 0;
- else {
- setobj(L->top, &G(L)->refArray[ref].o);
- api_incr_top(L);
- }
+ setobj(L->top, luaH_getnum(G(L)->weakregistry, ref));
+ status = (ttype(L->top) != LUA_TNIL);
}
+ if (status)
+ api_incr_top(L);
lua_unlock(L);
return status;
}
@@ -445,6 +442,22 @@ LUA_API void lua_newtable (lua_State *L) {
}
+LUA_API void lua_getregistry (lua_State *L) {
+ lua_lock(L);
+ sethvalue(L->top, G(L)->registry);
+ api_incr_top(L);
+ lua_unlock(L);
+}
+
+
+LUA_API void lua_getweakregistry (lua_State *L) {
+ lua_lock(L);
+ sethvalue(L->top, G(L)->weakregistry);
+ api_incr_top(L);
+ lua_unlock(L);
+}
+
+
/*
** set functions (stack -> Lua)
@@ -508,25 +521,26 @@ LUA_API void lua_setglobals (lua_State *L) {
LUA_API int lua_ref (lua_State *L, int lock) {
int ref;
- lua_lock(L);
- api_checknelems(L, 1);
- if (ttype(L->top-1) == LUA_TNIL)
+ if (lua_isnil(L, -1)) {
+ lua_pop(L, 1);
ref = LUA_REFNIL;
+ }
else {
- if (G(L)->refFree != NONEXT) { /* is there a free place? */
- ref = G(L)->refFree;
- G(L)->refFree = G(L)->refArray[ref].st;
- }
- else { /* no more free places */
- luaM_growvector(L, G(L)->refArray, G(L)->nref, G(L)->sizeref, struct Ref,
- MAX_INT, l_s("reference table overflow"));
- ref = G(L)->nref++;
+ lua_getweakregistry(L);
+ ref = lua_getn(L, -1) + 1;
+ lua_pushvalue(L, -2);
+ lua_rawseti(L, -2, ref);
+ if (lock) {
+ lua_getregistry(L);
+ lua_pushvalue(L, -3);
+ lua_rawseti(L, -2, ref);
+ lua_pop(L, 1); /* remove registry */
}
- setobj(&G(L)->refArray[ref].o, L->top-1);
- G(L)->refArray[ref].st = lock ? LOCK : HOLD;
+ lua_pushliteral(L, "n");
+ lua_pushnumber(L, ref);
+ lua_settable(L, -3);
+ lua_pop(L, 2);
}
- L->top--;
- lua_unlock(L);
return ref;
}
@@ -671,13 +685,15 @@ LUA_API void lua_error (lua_State *L, const l_char *s) {
LUA_API void lua_unref (lua_State *L, int ref) {
- lua_lock(L);
if (ref >= 0) {
- api_check(L, ref < G(L)->nref && G(L)->refArray[ref].st < 0);
- G(L)->refArray[ref].st = G(L)->refFree;
- G(L)->refFree = ref;
+ lua_getregistry(L);
+ lua_pushnil(L);
+ lua_rawseti(L, -2, ref);
+ lua_getweakregistry(L);
+ lua_pushnil(L);
+ lua_rawseti(L, -2, ref);
+ lua_pop(L, 2); /* remove both registries */
}
- lua_unlock(L);
}
diff --git a/lgc.c b/lgc.c
index a7f96f8c..0237b88c 100644
--- a/lgc.c
+++ b/lgc.c
@@ -1,5 +1,5 @@
/*
-** $Id: lgc.c,v 1.95 2001/03/26 14:31:49 roberto Exp roberto $
+** $Id: lgc.c,v 1.96 2001/04/11 14:42:41 roberto Exp roberto $
** Garbage Collector
** See Copyright Notice in lua.h
*/
@@ -111,15 +111,6 @@ static void markstacks (lua_State *L, GCState *st) {
}
-static void marklock (global_State *G, GCState *st) {
- int i;
- for (i=0; i<G->nref; i++) {
- if (G->refArray[i].st == LOCK)
- markobject(st, &G->refArray[i].o);
- }
-}
-
-
static void marktagmethods (global_State *G, GCState *st) {
int t;
for (t=0; t<G->ntag; t++) {
@@ -176,8 +167,9 @@ static void markall (lua_State *L) {
st.tmark = NULL;
marktagmethods(G(L), &st); /* mark tag methods */
markstacks(L, &st); /* mark all stacks */
- marklock(G(L), &st); /* mark locked objects */
marktable(&st, G(L)->type2tag);
+ marktable(&st, G(L)->registry);
+ marktable(&st, G(L)->weakregistry);
for (;;) { /* mark tables and closures */
if (st.cmark) {
Closure *f = st.cmark; /* get first closure from list */
@@ -208,26 +200,6 @@ static int hasmark (const TObject *o) {
}
-/* macro for internal debugging; check if a link of free refs is valid */
-#define VALIDLINK(L, st,n) (NONEXT <= (st) && (st) < (n))
-
-static void invalidaterefs (global_State *G) {
- int n = G->nref;
- int i;
- for (i=0; i<n; i++) {
- struct Ref *r = &G->refArray[i];
- if (r->st == HOLD && !hasmark(&r->o))
- r->st = COLLECTED;
- lua_assert((r->st == LOCK && hasmark(&r->o)) ||
- (r->st == HOLD && hasmark(&r->o)) ||
- r->st == COLLECTED ||
- r->st == NONEXT ||
- (r->st < n && VALIDLINK(L, G->refArray[r->st].st, n)));
- }
- lua_assert(VALIDLINK(L, G->refFree, n));
-}
-
-
static void invalidatetable (Hash *h) {
int i;
for (i=0; i<h->size; i++) {
@@ -408,7 +380,6 @@ void luaC_collect (lua_State *L, int all) {
void luaC_collectgarbage (lua_State *L) {
markall(L);
- invalidaterefs(G(L)); /* check unlocked references */
invalidatetables(G(L));
luaC_collect(L, 0);
checkMbuffer(L);
diff --git a/lstate.c b/lstate.c
index 1006dbec..63e15283 100644
--- a/lstate.c
+++ b/lstate.c
@@ -1,5 +1,5 @@
/*
-** $Id: lstate.c,v 1.60 2001/03/09 18:05:05 roberto Exp roberto $
+** $Id: lstate.c,v 1.61 2001/03/26 14:31:49 roberto Exp roberto $
** Global State
** See Copyright Notice in lua.h
*/
@@ -29,20 +29,6 @@ struct Sopen {
static void close_state (lua_State *L, lua_State *OL);
-/*
-** initialize ref array and registry
-*/
-#define INIT_REFSIZE 4
-
-static void ref_init (lua_State *L) {
- G(L)->refArray = luaM_newvector(L, INIT_REFSIZE, struct Ref);
- G(L)->sizeref = INIT_REFSIZE;
- sethvalue(&G(L)->refArray[0].o, luaH_new(L, 0));
- G(L)->refArray[0].st = LOCK;
- G(L)->nref = 1;
-}
-
-
/*
** open parts that may cause memory-allocation errors
*/
@@ -74,18 +60,16 @@ static void f_luaopen (lua_State *L, void *ud) {
G(L)->TMtable = NULL;
G(L)->sizeTM = 0;
G(L)->ntag = 0;
- G(L)->refArray = NULL;
- G(L)->nref = 0;
- G(L)->sizeref = 0;
- G(L)->refFree = NONEXT;
G(L)->nblocks = sizeof(lua_State) + sizeof(global_State);
luaD_init(L, so->stacksize); /* init stack */
L->gt = luaH_new(L, 10); /* table of globals */
G(L)->type2tag = luaH_new(L, 10);
+ G(L)->registry = luaH_new(L, 0);
+ G(L)->weakregistry = luaH_new(L, 0);
+ G(L)->weakregistry->weakmode = LUA_WEAK_VALUE; /* make weakregistry weak */
luaS_init(L);
luaX_init(L);
luaT_init(L);
- ref_init(L);
G(L)->GCthreshold = 4*G(L)->nblocks;
}
}
@@ -133,7 +117,6 @@ static void close_state (lua_State *L, lua_State *OL) {
lua_assert(G(L)->roottable == NULL);
luaS_freeall(L);
luaM_freearray(L, G(L)->TMtable, G(L)->sizeTM, struct TM);
- luaM_freearray(L, G(L)->refArray, G(L)->sizeref, struct Ref);
luaM_freearray(L, G(L)->Mbuffer, G(L)->Mbuffsize, l_char);
luaM_freelem(NULL, L->G, global_State);
}
diff --git a/lstate.h b/lstate.h
index 69fd02ad..7c0e808d 100644
--- a/lstate.h
+++ b/lstate.h
@@ -1,5 +1,5 @@
/*
-** $Id: lstate.h,v 1.54 2001/03/02 17:27:50 roberto Exp roberto $
+** $Id: lstate.h,v 1.55 2001/03/07 18:09:25 roberto Exp roberto $
** Global State
** See Copyright Notice in lua.h
*/
@@ -32,20 +32,6 @@
#endif
-/*
-** marks for Reference array
-*/
-#define NONEXT -1 /* to end the free list */
-#define HOLD -2
-#define COLLECTED -3
-#define LOCK -4
-
-
-struct Ref {
- TObject o;
- int st; /* can be LOCK, HOLD, COLLECTED, or next (for free list) */
-};
-
struct lua_longjmp; /* defined in ldo.c */
struct TM; /* defined in ltm.h */
@@ -70,13 +56,11 @@ typedef struct global_State {
stringtable strt; /* hash table for strings */
stringtable udt; /* hash table for udata */
Hash *type2tag; /* hash table from type names to tags */
+ Hash *registry; /* (strong) registry table */
+ Hash *weakregistry; /* weakregistry table */
struct TM *TMtable; /* table for tag methods */
int sizeTM; /* size of TMtable */
int ntag; /* number of tags in TMtable */
- struct Ref *refArray; /* locked objects */
- int nref; /* first unused element in refArray */
- int sizeref; /* size of refArray */
- int refFree; /* list of free positions in refArray */
lu_mem GCthreshold;
lu_mem nblocks; /* number of `bytes' currently allocated */
} global_State;
diff --git a/ltests.c b/ltests.c
index d012df8b..d761d065 100644
--- a/ltests.c
+++ b/ltests.c
@@ -1,5 +1,5 @@
/*
-** $Id: ltests.c,v 1.77 2001/03/26 14:31:49 roberto Exp roberto $
+** $Id: ltests.c,v 1.78 2001/04/11 14:42:41 roberto Exp roberto $
** Internal Module for Debugging of the Lua Implementation
** See Copyright Notice in lua.h
*/
@@ -383,21 +383,30 @@ static int string_query (lua_State *L) {
static int tref (lua_State *L) {
+ int level = lua_gettop(L);
luaL_checkany(L, 1);
lua_pushvalue(L, 1);
lua_pushnumber(L, lua_ref(L, luaL_opt_int(L, 2, 1)));
+ assert(lua_gettop(L) == level+1); /* +1 for result */
return 1;
}
static int getref (lua_State *L) {
- if (lua_getref(L, luaL_check_int(L, 1)))
+ int level = lua_gettop(L);
+ if (lua_getref(L, luaL_check_int(L, 1))) {
+ assert(lua_gettop(L) == level+1);
return 1;
- else
+ }
+ else {
+ assert(lua_gettop(L) == level);
return 0;
+ }
}
static int unref (lua_State *L) {
+ int level = lua_gettop(L);
lua_unref(L, luaL_check_int(L, 1));
+ assert(lua_gettop(L) == level);
return 0;
}
diff --git a/lua.h b/lua.h
index 313a32be..4bfbc336 100644
--- a/lua.h
+++ b/lua.h
@@ -1,8 +1,8 @@
/*
-** $Id: lua.h,v 1.94 2001/04/11 14:42:41 roberto Exp roberto $
+** $Id: lua.h,v 1.95 2001/04/11 18:39:37 roberto Exp roberto $
** Lua - An Extensible Extension Language
** TeCGraf: Grupo de Tecnologia em Computacao Grafica, PUC-Rio, Brazil
-** e-mail: lua@tecgraf.puc-rio.br
+** e-mail: info@lua.org
** www: http://www.lua.org
** See Copyright Notice at the end of this file
*/
@@ -29,24 +29,20 @@
/* pre-defined references */
#define LUA_NOREF (-2)
#define LUA_REFNIL (-1)
-#define LUA_REFREGISTRY 0
-
-/* pre-defined tags */
-#define LUA_NOTAG (-2)
-/* option for multiple returns in lua_call */
+/* option for multiple returns in `lua_call' */
#define LUA_MULTRET (-1)
-/* error codes for lua_do* */
+/* error codes for `lua_do*' and the like */
#define LUA_ERRRUN 1
#define LUA_ERRFILE 2
#define LUA_ERRSYNTAX 3
#define LUA_ERRMEM 4
#define LUA_ERRERR 5
-/* weak modes */
+/* weak-table modes */
#define LUA_WEAK_KEY 1
#define LUA_WEAK_VALUE 2
@@ -67,6 +63,11 @@ typedef int (*lua_CFunction) (lua_State *L);
#define LUA_TTABLE 4
#define LUA_TFUNCTION 5
+/*
+** an invalid `tag'
+*/
+#define LUA_NOTAG (-2)
+
/*
@@ -77,7 +78,7 @@ typedef int (*lua_CFunction) (lua_State *L);
#endif
-/* minimum stack available for a C function */
+/* minimum Lua stack available to a C function */
#define LUA_MINSTACK 20
@@ -163,6 +164,8 @@ LUA_API void lua_getglobals (lua_State *L);
LUA_API void lua_gettagmethod (lua_State *L, int tag, const lua_char *event);
LUA_API int lua_getref (lua_State *L, int ref);
LUA_API void lua_newtable (lua_State *L);
+LUA_API void lua_getregistry (lua_State *L);
+LUA_API void lua_getweakregistry (lua_State *L);
/*
@@ -241,8 +244,6 @@ LUA_API int lua_getweakmode (lua_State *L, int index);
#define lua_isnil(L,n) (lua_type(L,n) == LUA_TNIL)
#define lua_isnull(L,n) (lua_type(L,n) == LUA_TNONE)
-#define lua_getregistry(L) lua_getref(L, LUA_REFREGISTRY)
-
#define lua_pushliteral(L, s) lua_pushlstring(L, s, \
(sizeof(s)/sizeof(lua_char))-1)
--
cgit v1.2.3-55-g6feb