--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/share/vm/gc_implementation/shared/spaceDecorator.hpp	Mon Jul 28 15:30:23 2008 -0700
@@ -0,0 +1,141 @@
+/*
+ * Copyright 2002-2005 Sun Microsystems, Inc.  All Rights Reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ *
+ */
+
+class SpaceDecorator: public AllStatic {
+ public:
+  // Initialization flags.
+  static const bool Clear               = true;
+  static const bool DontClear           = false;
+  static const bool Mangle              = true;
+  static const bool DontMangle          = false;
+};
+
+// Functionality for use with class Space and class MutableSpace.
+//   The approach taken with the mangling is to mangle all
+// the space initially and then to mangle areas that have
+// been allocated since the last collection.  Mangling is
+// done in the context of a generation and in the context
+// of a space.
+//   The space in a generation is mangled when it is first
+// initialized and when the generation grows.  The spaces
+// are not necessarily up-to-date when this mangling occurs
+// and the method mangle_region() is used.
+//   After allocations have been done in a space, the space generally
+// need to be remangled.  Remangling is only done on the
+// recently allocated regions in the space.  Typically, that is
+// the region between the new top and the top just before a
+// garbage collection.
+//   An exception to the usual mangling in a space is done when the
+// space is used for an extraordinary purpose.  Specifically, when
+// to-space is used as scratch space for a mark-sweep-compact
+// collection.
+//   Spaces are mangled after a collection.  If the generation
+// grows after a collection, the added space is mangled as part of
+// the growth of the generation.  No additional mangling is needed when the
+// spaces are resized after an expansion.
+//   The class SpaceMangler keeps a pointer to the top of the allocated
+// area and provides the methods for doing the piece meal mangling.
+// Methods for doing sparces and full checking of the mangling are
+// included.  The full checking is done if DEBUG_MANGLING is defined.
+//   GenSpaceMangler is used with the GenCollectedHeap collectors and
+// MutableSpaceMangler is used with the ParallelScavengeHeap collectors.
+// These subclasses abstract the differences in the types of spaces used
+// by each heap.
+
+class SpaceMangler: public CHeapObj {
+  friend class VMStructs;
+
+  // High water mark for allocations.  Typically, the space above
+  // this point have been mangle previously and don't need to be
+  // touched again.  Space belows this point has been allocated
+  // and remangling is needed between the current top and this
+  // high water mark.
+  HeapWord* _top_for_allocations;
+  HeapWord* top_for_allocations() { return _top_for_allocations; }
+
+ public:
+
+  // Setting _top_for_allocations to NULL at initialization
+  // makes it always below top so that mangling done as part
+  // of the initialize() call of a space does nothing (as it
+  // should since the mangling is done as part of the constructor
+  // for the space.
+  SpaceMangler() : _top_for_allocations(NULL) {}
+
+  // Methods for top and end that delegate to the specific
+  // space type.
+  virtual HeapWord* top() const = 0;
+  virtual HeapWord* end() const = 0;
+
+  // Return true if q matches the mangled pattern.
+  static bool is_mangled(HeapWord* q) PRODUCT_RETURN0;
+
+  // Used to save the an address in a space for later use during mangling.
+  void set_top_for_allocations(HeapWord* v);
+
+  // Overwrites the unused portion of this space.
+  // Mangle only the region not previously mangled [top, top_previously_mangled)
+  void mangle_unused_area();
+  // Mangle all the unused region [top, end)
+  void mangle_unused_area_complete();
+  // Do some sparse checking on the area that should have been mangled.
+  void check_mangled_unused_area(HeapWord* limit) PRODUCT_RETURN;
+  // Do a complete check of the area that should be mangled.
+  void check_mangled_unused_area_complete() PRODUCT_RETURN;
+
+  // Mangle the MemRegion.  This is a non-space specific mangler.  It
+  // is used during the initial mangling of a space before the space
+  // is fully constructed.  Also is used when a generation is expanded
+  // and possibly before the spaces have been reshaped to to the new
+  // size of the generation.
+  static void mangle_region(MemRegion mr);
+};
+
+class ContiguousSpace;
+
+// For use with GenCollectedHeap's
+class GenSpaceMangler: public SpaceMangler {
+  ContiguousSpace* _sp;
+
+  ContiguousSpace* sp() { return _sp; }
+
+  HeapWord* top() const { return _sp->top(); }
+  HeapWord* end() const { return _sp->end(); }
+
+ public:
+  GenSpaceMangler(ContiguousSpace* sp) : SpaceMangler(), _sp(sp) {}
+};
+
+// For use with ParallelScavengeHeap's.
+class MutableSpaceMangler: public SpaceMangler {
+  MutableSpace* _sp;
+
+  MutableSpace* sp() { return _sp; }
+
+  HeapWord* top() const { return _sp->top(); }
+  HeapWord* end() const { return _sp->end(); }
+
+ public:
+  MutableSpaceMangler(MutableSpace* sp) : SpaceMangler(), _sp(sp) {}
+};