new interface for weak modes

lapi.c

@@ -695,28 +695,7 @@ LUA_API void lua_newuserdatabox (lua_State *L, void *p) {
 }
 
 
-LUA_API int lua_getweakmode (lua_State *L, int index) {
-  StkId t;
-  int mode;
-  lua_lock(L);
-  t = luaA_index(L, index);
-  api_check(L, ttype(t) == LUA_TTABLE);
-  mode = hvalue(t)->weakmode;
-  lua_unlock(L);
-  return mode;
-}
-
-
-LUA_API void  lua_setweakmode (lua_State *L, int mode) {
-  lua_lock(L);
-  api_check(L, ttype(L->top-1) == LUA_TTABLE);
-  hvalue(L->top-1)->weakmode = cast(lu_byte, mode);
-  lua_unlock(L);
-}
-
-
-
-LUA_API void lua_pushupvalues (lua_State *L) {
+LUA_API int lua_pushupvalues (lua_State *L) {
   TObject *func;
   int n, i;
   lua_lock(L);
@@ -730,6 +709,7 @@ LUA_API void lua_pushupvalues (lua_State *L) {
     L->top++;
   }
   lua_unlock(L);
+  return n;
 }
 
 

lgc.c

@@ -4,6 +4,8 @@
 ** See Copyright Notice in lua.h
 */
 
+#include <string.h>
+
 #include "lua.h"
 
 #include "ldebug.h"
@@ -22,6 +24,7 @@
 typedef struct GCState {
   Table *tmark;  /* list of marked tables to be visited */
   Table *toclear;  /* list of visited weak tables (to be cleared after GC) */
+  lua_State *L;
 } GCState;
 
 
@@ -119,8 +122,8 @@ static void markobject (GCState *st, TObject *o) {
 }
 
 
-static void markstacks (lua_State *L, GCState *st) {
-  lua_State *L1 = L;
+static void markstacks (GCState *st) {
+  lua_State *L1 = st->L;
   do {  /* for each thread */
     StkId o, lim;
     for (o=L1->stack; o<L1->top; o++)
@@ -130,15 +133,15 @@ static void markstacks (lua_State *L, GCState *st) {
     for (; o<=lim; o++) setnilvalue(o);
     lua_assert(L1->previous->next == L1 && L1->next->previous == L1);
     L1 = L1->next;
-  } while (L1 != L);
+  } while (L1 != st->L);
 }
 
 
-static void markudet (lua_State *L, GCState *st) {
+static void markudet (GCState *st) {
   Udata *u;
-  for (u = G(L)->rootudata; u; u = u->uv.next)
+  for (u = G(st->L)->rootudata; u; u = u->uv.next)
     marktable(st, u->uv.eventtable);
-  for (u = G(L)->tmudata; u; u = u->uv.next)
+  for (u = G(st->L)->tmudata; u; u = u->uv.next)
     marktable(st, u->uv.eventtable);
 }
 
@@ -152,13 +155,20 @@ static void removekey (Node *n) {
 
 static void traversetable (GCState *st, Table *h) {
   int i;
-  int mode = h->weakmode;
+  const TObject *mode;
+  int weakkey = 0;
+  int weakvalue = 0;
+  marktable(st, h->eventtable);
+  mode = fasttm(st->L, h->eventtable, TM_WEAKMODE);
   if (mode) {  /* weak table? must be cleared after GC... */
     h->mark = st->toclear;  /* put in the appropriate list */
     st->toclear = h;
+    if (ttype(mode) == LUA_TSTRING) {
+      weakkey = (strchr(svalue(mode), 'k') != NULL);
+      weakvalue = (strchr(svalue(mode), 'v') != NULL);
+    }
   }
-  marktable(st, h->eventtable);
-  if (!(mode & LUA_WEAK_VALUE)) {
+  if (!weakvalue) {
     i = sizearray(h);
     while (i--)
       markobject(st, &h->array[i]);
@@ -168,18 +178,18 @@ static void traversetable (GCState *st, Table *h) {
     Node *n = node(h, i);
     if (ttype(val(n)) != LUA_TNIL) {
       lua_assert(ttype(key(n)) != LUA_TNIL);
-      if (!(mode & LUA_WEAK_KEY))
-        markobject(st, key(n));
-      if (!(mode & LUA_WEAK_VALUE))
-        markobject(st, val(n));
+      if (!weakkey) markobject(st, key(n));
+      if (!weakvalue) markobject(st, val(n));
     }
   }
 }
 
 
-static void markall (lua_State *L, GCState *st) {
-  markstacks(L, st); /* mark all stacks */
-  markudet(L, st);  /* mark userdata's event tables */
+static void markall (GCState *st) {
+  lua_assert(hvalue(defaultet(st->L))->flags == cast(unsigned short, ~0));
+                                                      /* table is unchanged */
+  markstacks(st); /* mark all stacks */
+  markudet(st);  /* mark userdata's event tables */
   while (st->tmark) {  /* traverse marked tables */
     Table *h = st->tmark;  /* get first table from list */
     st->tmark = h->mark;  /* remove it from list */
@@ -210,7 +220,6 @@ static int hasmark (const TObject *o) {
 static void cleartables (Table *h) {
   for (; h; h = h->mark) {
     int i;
-    lua_assert(h->weakmode);
     i = sizearray(h);
     while (i--) {
       TObject *o = &h->array[i];
@@ -421,9 +430,10 @@ void luaC_collect (lua_State *L, int all) {
 
 void luaC_collectgarbage (lua_State *L) {
   GCState st;
+  st.L = L;
   st.tmark = NULL;
   st.toclear = NULL;
-  markall(L, &st);
+  markall(&st);
   cleartables(st.toclear);
   luaC_collect(L, 0);
   checkMbuffer(L);

lobject.h

@@ -214,9 +214,9 @@ typedef union Closure {
 */
 
 typedef struct Node {
-  struct Node *next;  /* for chaining */
   TObject _key;
   TObject _val;
+  struct Node *next;  /* for chaining */
 } Node;
 
 
@@ -226,7 +226,6 @@ typedef struct Table {
   Node *node;
   int sizearray;  /* size of `array' array */
   lu_byte lsizenode;  /* log2 of size of `node' array */
-  lu_byte weakmode;
   unsigned short flags;  /* 1<<p means tagmethod(p) is not present */ 
   Node *firstfree;  /* this position is free; all positions after it are full */
   struct Table *next;

ltable.c

@@ -274,7 +274,6 @@ Table *luaH_new (lua_State *L, int narray, int lnhash) {
   t->next = G(L)->roottable;
   G(L)->roottable = t;
   t->mark = t;
-  t->weakmode = 0;
   t->flags = cast(unsigned short, ~0);
   /* temporary values (kept only if some malloc fails) */
   t->array = NULL;

ltm.c

@@ -26,7 +26,7 @@ const char *const luaT_typenames[] = {
 void luaT_init (lua_State *L) {
   static const char *const luaT_eventname[] = {  /* ORDER TM */
     "gettable", "settable", "index",
-    "gc",
+    "gc", "weakmode",
     "add", "sub", "mul", "div",
     "pow", "unm", "lt", "concat",
     "call"

ltm.h

@@ -19,6 +19,7 @@ typedef enum {
   TM_SETTABLE,
   TM_INDEX,
   TM_GC,
+  TM_WEAKMODE,
   TM_ADD,
   TM_SUB,
   TM_MUL,