do fetch and remove a the same time: PopFromDB

C/dbase.c

@@ -4944,6 +4944,42 @@ Yap_FetchTermFromDB(DBTerm *ref)
   return GetDBTerm(ref);
 }
 
+Term 
+Yap_PopTermFromDB(DBTerm *ref)
+{
+  Term t = GetDBTerm(ref);
+  DBRef *cp = ref->DBRefs;
+
+  if (cp) {
+    DBRef eref;
+
+    while ((eref = *--cp) != NIL) {
+      if (eref->Flags & LogUpdMask) {
+	LogUpdClause *cl = (LogUpdClause *)eref;
+	cl->ClRefCount--;
+	if (cl->ClFlags & ErasedMask &&
+	    !(cl->ClFlags & InUseMask) &&
+	    !(cl->ClRefCount)) {
+	  EraseLogUpdCl(cl);
+	}
+      } else {
+	LOCK(eref->lock);
+	eref->NOfRefsTo--;
+	if (eref->Flags & ErasedMask &&
+	    !(eref->Flags & InUseMask) &&
+	    eref->NOfRefsTo) {
+	  UNLOCK(eref->lock);
+	  ErDBE(eref);
+	} else {
+	  UNLOCK(ref->lock);
+	}
+      }
+    }
+  }
+  Yap_FreeCodeSpace((char *)ref);
+  return t;
+}
+
 static DBTerm *
 StoreTermInDB(Term t, int nargs)
 {

C/exec.c

@@ -1463,6 +1463,31 @@ suspended_on_current_execution(Term t, Term t0)
   return t0 == ArgOfTerm(1, t1);
 }
 
+static Term
+get_term(DBTerm *dbt, Term t)
+{
+  if (dbt) {
+    while (!(t = Yap_PopTermFromDB(dbt))) {
+      if (Yap_Error_TYPE == OUT_OF_ATTVARS_ERROR) {
+	Yap_Error_TYPE = YAP_NO_ERROR;
+	if (!Yap_growglobal(NULL)) {
+	  t = MkAtomTerm(AtomOutOfStackError);
+	}
+      } else {
+	Yap_Error_TYPE = YAP_NO_ERROR;
+	if (!Yap_growstack(dbt->NOfCells*CellSize)) {
+	  t = MkAtomTerm(AtomOutOfStackError);
+	}
+      }
+    }
+    if (t) {
+      B->cp_h = H;
+    }
+  }
+  return t;
+}
+
+
 static Term
 clean_trail(Term t, DBTerm *dbt, Term t0)
 {
@@ -1495,14 +1520,7 @@ clean_trail(Term t, DBTerm *dbt, Term t0)
 	  if (suspended_on_current_execution(val, t0)) {
 	    RESET_VARIABLE(&TrailTerm(pt1));
 	  } else {
-	    if (dbt) {
+	    t = get_term(dbt, t);
-	      t = Yap_FetchTermFromDB(dbt);
-	      if (t) {
-		B->cp_h = H;
-	      } else {
-		t = MkAtomTerm(AtomDAbort);
-	      }
-	    }
 	    Bind(pt, t);
 	    Yap_WakeUp(pt);
 	    return t;
@@ -1524,14 +1542,7 @@ clean_trail(Term t, DBTerm *dbt, Term t0)
 #endif /* FROZEN_STACKS */
     }
   }
-  if (dbt) {
+  t = get_term(dbt, t);
-    t = Yap_FetchTermFromDB(dbt);
-    if (t) {
-      B->cp_h = H;
-    } else {
-      t = MkAtomTerm(AtomDAbort);
-    }
-  }
   return t;
 }
 

C/threads.c

@@ -185,7 +185,7 @@ thread_run(void *widp)
 
   start_thread(myworker_id);
   do {
-    t = tgs[0] = Yap_FetchTermFromDB(ThreadHandle[worker_id].tgoal);
+    t = tgs[0] = Yap_PopTermFromDB(ThreadHandle[worker_id].tgoal);
     if (t == 0) {
       if (Yap_Error_TYPE == OUT_OF_ATTVARS_ERROR) {
 	Yap_Error_TYPE = YAP_NO_ERROR;
@@ -204,7 +204,6 @@ thread_run(void *widp)
       }
     }
   } while (t == 0);
-  Yap_ReleaseTermFromDB(ThreadHandle[myworker_id].tgoal);
   ThreadHandle[myworker_id].tgoal = NULL;
   tgs[1] = ThreadHandle[worker_id].tdetach;
   tgoal = Yap_MkApplTerm(FunctorThreadRun, 2, tgs);
@@ -716,7 +715,8 @@ p_thread_atexit(void)
     return FALSE;
   }
   do {
-    t = Yap_FetchTermFromDB(ThreadHandle[worker_id].texit);
+    t = Yap_PopTermFromDB(ThreadHandle[worker_id].texit);
+    ThreadHandle[worker_id].texit = NULL;
     if (t == 0) {
       if (Yap_Error_TYPE == OUT_OF_ATTVARS_ERROR) {
 	Yap_Error_TYPE = YAP_NO_ERROR;

H/Yatom.h

@@ -1363,6 +1363,7 @@ void STD_PROTO (Yap_ErDBE, (DBRef));
 DBTerm *STD_PROTO (Yap_StoreTermInDB, (Term, int));
 DBTerm *STD_PROTO (Yap_StoreTermInDBPlusExtraSpace, (Term, UInt, UInt *));
 Term STD_PROTO (Yap_FetchTermFromDB, (DBTerm *));
+Term STD_PROTO (Yap_PopTermFromDB, (DBTerm *));
 void STD_PROTO (Yap_ReleaseTermFromDB, (DBTerm *));
 
 /* init.c */