support for multiple stacks sharing the same global environment

lgc.c

@@ -1,5 +1,5 @@
 /*
-** $Id: lgc.c,v 1.76 2001/01/18 15:59:09 roberto Exp roberto $
+** $Id: lgc.c,v 1.77 2001/01/19 13:20:30 roberto Exp roberto $
 ** Garbage Collector
 ** See Copyright Notice in lua.h
 */
@@ -47,22 +47,6 @@ static void protomark (Proto *f) {
 }
 
 
-static void markstack (lua_State *L, GCState *st) {
-  StkId o;
-  for (o=L->stack; o<L->top; o++)
-    markobject(st, o);
-}
-
-
-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 markclosure (GCState *st, Closure *cl) {
   if (!ismarked(cl)) {
     if (!cl->isC)
@@ -73,14 +57,10 @@ static void markclosure (GCState *st, Closure *cl) {
 }
 
 
-static void marktagmethods (global_State *G, GCState *st) {
-  int e;
-  for (e=0; e<TM_N; e++) {
-    int t;
-    for (t=0; t<G->ntag; t++) {
-      Closure *cl = luaT_gettm(G, t, e);
-      if (cl) markclosure(st, cl);
-    }
+static void marktable (GCState *st, Hash *h) {
+  if (!ismarked(h)) {
+    h->mark = st->tmark;  /* chain it in list of marked */
+    st->tmark = h;
   }
 }
 
@@ -97,10 +77,7 @@ static void markobject (GCState *st, TObject *o) {
       markclosure(st, clvalue(o));
       break;
     case LUA_TTABLE: {
-      if (!ismarked(hvalue(o))) {
-        hvalue(o)->mark = st->tmark;  /* chain it in list of marked */
-        st->tmark = hvalue(o);
-      }
+      marktable(st, hvalue(o));
       break;
     }
     default: break;  /* numbers, etc */
@@ -108,13 +85,46 @@ static void markobject (GCState *st, TObject *o) {
 }
 
 
+static void markstacks (lua_State *L, GCState *st) {
+  lua_State *L1 = L;
+  do {  /* for each thread */
+    StkId o;
+    marktable(st, L1->gt);  /* mark table of globals */
+    for (o=L1->stack; o<L1->top; o++)
+      markobject(st, o);
+    lua_assert(L->previous->next == L && L->next->previous == L);
+    L1 = L1->next;
+  } while (L1 != L);
+}
+
+
+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 e;
+  for (e=0; e<TM_N; e++) {
+    int t;
+    for (t=0; t<G->ntag; t++) {
+      Closure *cl = luaT_gettm(G, t, e);
+      if (cl) markclosure(st, cl);
+    }
+  }
+}
+
+
 static void markall (lua_State *L) {
   GCState st;
   st.cmark = NULL;
-  st.tmark = L->gt;  /* put table of globals in mark list */
-  L->gt->mark = NULL;
+  st.tmark = NULL;
   marktagmethods(G(L), &st);  /* mark tag methods */
-  markstack(L, &st); /* mark stack objects */
+  markstacks(L, &st); /* mark all stacks */
   marklock(G(L), &st); /* mark locked objects */
   for (;;) {  /* mark tables and closures */
     if (st.cmark) {

lstate.c

@@ -1,5 +1,5 @@
 /*
-** $Id: lstate.c,v 1.50 2000/12/28 12:55:41 roberto Exp roberto $
+** $Id: lstate.c,v 1.51 2001/01/19 13:20:30 roberto Exp roberto $
 ** Global State
 ** See Copyright Notice in lua.h
 */
@@ -38,52 +38,70 @@ static int errormessage (lua_State *L) {
 }
 
 
+struct Sopen {
+  int stacksize;
+  lua_State *L;
+};
+
+
 /*
 ** open parts that may cause memory-allocation errors
 */
 static void f_luaopen (lua_State *L, void *ud) {
-  int stacksize = *(int *)ud;
-  if (stacksize == 0)
-    stacksize = DEFAULT_STACK_SIZE;
+  struct Sopen *so = (struct Sopen *)ud;
+  if (so->stacksize == 0)
+    so->stacksize = DEFAULT_STACK_SIZE;
   else
-    stacksize += LUA_MINSTACK;
-  L->G = luaM_new(L, global_State);
-  G(L)->strt.size = G(L)->udt.size = 0;
-  G(L)->strt.nuse = G(L)->udt.nuse = 0;
-  G(L)->strt.hash = G(L)->udt.hash = NULL;
-  G(L)->Mbuffer = NULL;
-  G(L)->Mbuffsize = 0;
-  G(L)->rootproto = NULL;
-  G(L)->rootcl = NULL;
-  G(L)->roottable = NULL;
-  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);
-  G(L)->GCthreshold = MAX_INT;  /* to avoid GC during pre-definitions */
-  L->gt = luaH_new(L, 10);  /* table of globals */
-  luaD_init(L, stacksize);
-  luaS_init(L);
-  luaX_init(L);
-  luaT_init(L);
-  lua_newtable(L);
-  lua_ref(L, 1);  /* create registry */
-  lua_register(L, LUA_ERRORMESSAGE, errormessage);
+    so->stacksize += LUA_MINSTACK;
+  if (so->L != NULL) {  /* shared global state? */
+    L->G = G(so->L);
+    L->gt = so->L->gt;  /* share table of globals */
+    so->L->next->previous = L;  /* insert L into linked list */
+    L->next = so->L->next;
+    so->L->next = L;
+    L->previous = so->L;
+    luaD_init(L, so->stacksize);  /* init stack */
+  }
+  else {  /* create a new global state */
+    L->G = luaM_new(L, global_State);
+    G(L)->strt.size = G(L)->udt.size = 0;
+    G(L)->strt.nuse = G(L)->udt.nuse = 0;
+    G(L)->strt.hash = G(L)->udt.hash = NULL;
+    G(L)->Mbuffer = NULL;
+    G(L)->Mbuffsize = 0;
+    G(L)->rootproto = NULL;
+    G(L)->rootcl = NULL;
+    G(L)->roottable = NULL;
+    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);
+    G(L)->GCthreshold = MAX_INT;  /* to avoid GC during pre-definitions */
+    luaD_init(L, so->stacksize);  /* init stack */
+    L->gt = luaH_new(L, 10);  /* table of globals */
+    luaS_init(L);
+    luaX_init(L);
+    luaT_init(L);
+    lua_newtable(L);
+    lua_ref(L, 1);  /* create registry */
+    lua_register(L, LUA_ERRORMESSAGE, errormessage);
 #ifdef LUA_DEBUG
-  luaB_opentests(L);
-  if (lua_state == NULL) lua_state = L;  /* keep first state to be opened */
-  lua_assert(lua_gettop(L) == 0);
+    luaB_opentests(L);
+    if (lua_state == NULL) lua_state = L;  /* keep first state to be opened */
+    lua_assert(lua_gettop(L) == 0);
 #endif
+    G(L)->GCthreshold = 2*G(L)->nblocks;
+  }
 }
 
 
-LUA_API lua_State *lua_open (int stacksize) {
-  lua_State *L;
-  L = luaM_new(NULL, lua_State);
+LUA_API lua_State *lua_open (lua_State *OL, int stacksize) {
+  struct Sopen so;
+  lua_State *L = luaM_new(OL, lua_State);
   if (L == NULL) return NULL;  /* memory allocation error */
   L->G = NULL;
   L->stack = NULL;
@@ -92,19 +110,28 @@ LUA_API lua_State *lua_open (int stacksize) {
   L->callhook = NULL;
   L->linehook = NULL;
   L->allowhooks = 1;
-  if (luaD_runprotected(L, f_luaopen, &stacksize) != 0) {
+  L->next = L->previous = L;
+  so.stacksize = stacksize;
+  so.L = OL;
+  if (luaD_runprotected(L, f_luaopen, &so) != 0) {
     /* memory allocation error: free partial state */
     lua_close(L);
     return NULL;
   }
-  G(L)->GCthreshold = 2*G(L)->nblocks;
   return L;
 }
 
 
 LUA_API void lua_close (lua_State *L) {
+  lua_State *L1 = L->next;  /* any surviving thread (if there is one) */
   lua_assert(L != lua_state || lua_gettop(L) == 0);
-  if (G(L)) {  /* close global state */
+  if (L1 == L) L1 = NULL;  /* no surviving threads */
+  if (L1 != NULL) {  /* are there other threads? */
+    lua_assert(L->previous != L);
+    L->previous->next = L->next;
+    L->next->previous = L->previous;
+  }
+  else if (G(L)) {  /* last thread; close global state */
     luaC_collect(L, 1);  /* collect all elements */
     lua_assert(G(L)->rootproto == NULL);
     lua_assert(G(L)->rootcl == NULL);
@@ -115,8 +142,8 @@ LUA_API void lua_close (lua_State *L) {
     luaM_freearray(L, G(L)->Mbuffer, G(L)->Mbuffsize, char);
     luaM_freelem(NULL, L->G, global_State);
   }
-  luaM_freearray(NULL, L->stack, L->stacksize, TObject);
-  luaM_freelem(NULL, L, lua_State);
+  luaM_freearray(L1, L->stack, L->stacksize, TObject);
+  luaM_freelem(L1, L, lua_State);
   lua_assert(L != lua_state || memdebug_numblocks == 0);
   lua_assert(L != lua_state || memdebug_total == 0);
 }

lstate.h

@@ -1,5 +1,5 @@
 /*
-** $Id: lstate.h,v 1.43 2000/12/26 18:46:09 roberto Exp roberto $
+** $Id: lstate.h,v 1.44 2001/01/19 13:20:30 roberto Exp roberto $
 ** Global State
 ** See Copyright Notice in lua.h
 */
@@ -74,12 +74,14 @@ struct lua_State {
   StkId stack_last;  /* last free slot in the stack */
   int stacksize;
   StkId Cbase;  /* base for current C function */
-  struct lua_longjmp *errorJmp;  /* current error recover point */
   Hash *gt;  /* table for globals */
+  global_State *G;
   lua_Hook callhook;
   lua_Hook linehook;
   int allowhooks;
-  global_State *G;
+  struct lua_longjmp *errorJmp;  /* current error recover point */
+  lua_State *next;  /* circular double linked list of states */
+  lua_State *previous;
 };
 
 

ltests.c

@@ -1,5 +1,5 @@
 /*
-** $Id: ltests.c,v 1.57 2001/01/18 15:59:09 roberto Exp roberto $
+** $Id: ltests.c,v 1.58 2001/01/19 13:20:30 roberto Exp roberto $
 ** Internal Module for Debugging of the Lua Implementation
 ** See Copyright Notice in lua.h
 */
@@ -270,8 +270,19 @@ static int udataval (lua_State *L) {
   return 1;
 }
 
+
+static int doonnewstack (lua_State *L) {
+  lua_State *L1 = lua_open(L, luaL_check_int(L, 1));
+  if (L1 == NULL) return 0;
+  lua_dostring(L1, luaL_check_string(L, 2));
+  lua_pushnumber(L, 1);
+  lua_close(L1);
+  return 1;
+}
+
+
 static int newstate (lua_State *L) {
-  lua_State *L1 = lua_open(luaL_check_int(L, 1));
+  lua_State *L1 = lua_open(NULL, luaL_check_int(L, 1));
   if (L1)
     lua_pushuserdata(L, L1);
   else
@@ -518,6 +529,7 @@ static const struct luaL_reg tests_funcs[] = {
   {"unref", unref},
   {"newuserdata", newuserdata},
   {"udataval", udataval},
+  {"doonnewstack", doonnewstack},
   {"newstate", newstate},
   {"closestate", closestate},
   {"doremote", doremote},

lua.c

@@ -1,5 +1,5 @@
 /*
-** $Id: lua.c,v 1.55 2000/10/20 16:36:32 roberto Exp roberto $
+** $Id: lua.c,v 1.56 2001/01/10 16:58:11 roberto Exp roberto $
 ** Lua stand-alone interpreter
 ** See Copyright Notice in lua.h
 */
@@ -311,7 +311,7 @@ int main (int argc, char *argv[]) {
   int status;
   opt.toclose = 0;
   getstacksize(argc, argv, &opt);  /* handle option `-s' */
-  L = lua_open(opt.stacksize);  /* create state */
+  L = lua_open(NULL, opt.stacksize);  /* create state */
   userinit();  /* open libraries */
   register_getargs(argv);  /* create `getargs' function */
   status = handle_argv(argv+1, &opt);

lua.h

@@ -1,5 +1,5 @@
 /*
-** $Id: lua.h,v 1.81 2000/12/22 16:58:41 roberto Exp roberto $
+** $Id: lua.h,v 1.82 2001/01/10 16:58:11 roberto Exp roberto $
 ** Lua - An Extensible Extension Language
 ** TeCGraf: Grupo de Tecnologia em Computacao Grafica, PUC-Rio, Brazil
 ** e-mail: [email protected]
@@ -81,7 +81,7 @@ typedef int (*lua_CFunction) (lua_State *L);
 /*
 ** state manipulation
 */
-LUA_API lua_State *lua_open (int stacksize);
+LUA_API lua_State *lua_open (lua_State *L, int stacksize);
 LUA_API void       lua_close (lua_State *L);