emergency garbage collector (core forces a GC when allocation fails)

1 files changed, 19 insertions, 6 deletions

diff --git a/lmem.c b/lmem.c
index 1a3e25c4..fb383d3e 100644
--- a/lmem.c
+++ b/lmem.c
@@ -1,5 +1,5 @@
 /*
-** $Id: lmem.c,v 1.69 2005/02/23 17:30:22 roberto Exp roberto $
+** $Id: lmem.c,v 1.70 2005/12/26 13:35:47 roberto Exp roberto $
 ** Interface to Memory Manager
 ** See Copyright Notice in lua.h
 */
@@ -14,6 +14,7 @@
 
 #include "ldebug.h"
 #include "ldo.h"
+#include "lgc.h"
 #include "lmem.h"
 #include "lobject.h"
 #include "lstate.h"
@@ -74,13 +75,25 @@ void *luaM_toobig (lua_State *L) {
 ** generic allocation routine.
 */
 void *luaM_realloc_ (lua_State *L, void *block, size_t osize, size_t nsize) {
+  void *newblock;
   global_State *g = G(L);
   lua_assert((osize == 0) == (block == NULL));
-  block = (*g->frealloc)(g->ud, block, osize, nsize);
-  if (block == NULL && nsize > 0)
-    luaD_throw(L, LUA_ERRMEM);
-  lua_assert((nsize == 0) == (block == NULL));
+#if defined(HARDMEMTESTS)
+  if (nsize > osize && g->GCthreshold != MAX_LUMEM)
+    luaC_fullgc(L, 1);  /* force a GC whenever possible */
+#endif
+  newblock = (*g->frealloc)(g->ud, block, osize, nsize);
+  if (newblock == NULL && nsize > 0) {
+    lua_assert(nsize > osize);  /* cannot fail when shrinking a block */
+    if (g->GCthreshold != MAX_LUMEM) {
+      luaC_fullgc(L, 1);  /* try to free some memory... */
+      newblock = (*g->frealloc)(g->ud, block, osize, nsize);  /* try again */
+    }
+    if (newblock == NULL)
+      luaD_throw(L, LUA_ERRMEM);
+  }
+  lua_assert((nsize == 0) == (newblock == NULL));
   g->totalbytes = (g->totalbytes - osize) + nsize;
-  return block;
+  return newblock;
 }