/*

 * Copyright 2001-2007 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 Generation;

class HeapWord;

class CardTableRS;

class CardTableModRefBS;

class DefNewGeneration;

// Closure for iterating roots from a particular generation

// Note: all classes deriving from this MUST call this do_barrier

// method at the end of their own do_oop method!

// Note: no do_oop defined, this is an abstract class.

class OopsInGenClosure : public OopClosure {

 private:

  Generation*         _orig_gen;     // generation originally set in ctor

  Generation*         _gen;          // generation being scanned

 protected:

  // Some subtypes need access.

  HeapWord*           _gen_boundary; // start of generation

  CardTableRS*        _rs;           // remembered set

  // For assertions

  Generation* generation() { return _gen; }

  CardTableRS* rs() { return _rs; }

  // Derived classes that modify oops so that they might be old-to-young

  // pointers must call the method below.

  void do_barrier(oop* p);

 public:

  OopsInGenClosure() : OopClosure(NULL),

    _orig_gen(NULL), _gen(NULL), _gen_boundary(NULL), _rs(NULL) {};

  OopsInGenClosure(Generation* gen);

  void set_generation(Generation* gen);

  void reset_generation() { _gen = _orig_gen; }

  // Problem with static closures: must have _gen_boundary set at some point,

  // but cannot do this until after the heap is initialized.

  void set_orig_generation(Generation* gen) {

    _orig_gen = gen;

    set_generation(gen);

  }

  HeapWord* gen_boundary() { return _gen_boundary; }

};

// Closure for scanning DefNewGeneration.

//

// This closure will perform barrier store calls for ALL

// pointers in scanned oops.

class ScanClosure: public OopsInGenClosure {

protected:

  DefNewGeneration* _g;

  HeapWord* _boundary;

  bool _gc_barrier;

public:

  ScanClosure(DefNewGeneration* g, bool gc_barrier);

  void do_oop(oop* p);

  void do_oop_nv(oop* p);

  bool do_header() { return false; }

  Prefetch::style prefetch_style() {

    return Prefetch::do_write;

  }

};

// Closure for scanning DefNewGeneration.

//

// This closure only performs barrier store calls on

// pointers into the DefNewGeneration. This is less

// precise, but faster, than a ScanClosure

class FastScanClosure: public OopsInGenClosure {

protected:

  DefNewGeneration* _g;

  HeapWord* _boundary;

  bool _gc_barrier;

public:

  FastScanClosure(DefNewGeneration* g, bool gc_barrier);

  void do_oop(oop* p);

  void do_oop_nv(oop* p);

  bool do_header() { return false; }

  Prefetch::style prefetch_style() {

    return Prefetch::do_write;

  }

};

class FilteringClosure: public OopClosure {

  HeapWord* _boundary;

  OopClosure* _cl;

public:

  FilteringClosure(HeapWord* boundary, OopClosure* cl) :

    OopClosure(cl->_ref_processor), _boundary(boundary),

    _cl(cl) {}

  void do_oop(oop* p);

  void do_oop_nv(oop* p) {

    oop obj = *p;

    if ((HeapWord*)obj < _boundary && obj != NULL) {

      _cl->do_oop(p);

    }

  }

  bool do_header() { return false; }

};

// Closure for scanning DefNewGeneration's weak references.

// NOTE: very much like ScanClosure but not derived from

//  OopsInGenClosure -- weak references are processed all

//  at once, with no notion of which generation they were in.

class ScanWeakRefClosure: public OopClosure {

protected:

  DefNewGeneration*  _g;

  HeapWord*          _boundary;

public:

  ScanWeakRefClosure(DefNewGeneration* g);

  void do_oop(oop* p);

  void do_oop_nv(oop* p);

};

class VerifyOopClosure: public OopClosure {

public:

  void do_oop(oop* p) {

    guarantee((*p)->is_oop_or_null(), "invalid oop");

  }

  static VerifyOopClosure verify_oop;

};