/*

 * 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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 */

#include "memory/allocation.hpp"

class FreeIdSet;

// A closure class for processing card table entries.  Note that we don't

// require these closure objects to be stack-allocated.

class CardTableEntryClosure: public CHeapObj<mtGC> {

public:

  // Process the card whose card table entry is "card_ptr".  If returns

  // "false", terminate the iteration early.

  virtual bool do_card_ptr(jbyte* card_ptr, uint worker_i = 0) = 0;

};

// A ptrQueue whose elements are "oops", pointers to object heads.

class DirtyCardQueue: public PtrQueue {

public:

  DirtyCardQueue(PtrQueueSet* qset_, bool perm = false) :

    // Dirty card queues are always active, so we create them with their

    // active field set to true.

    PtrQueue(qset_, perm, true /* active */) { }

  // Flush before destroying; queue may be used to capture pending work while

  // doing something else, with auto-flush on completion.

  ~DirtyCardQueue() { if (!is_permanent()) flush(); }

  // Process queue entries and release resources.

  void flush() { flush_impl(); }

  // Apply the closure to all elements, and reset the index to make the

  // buffer empty.  If a closure application returns "false", return

  // "false" immediately, halting the iteration.  If "consume" is true,

  // deletes processed entries from logs.

  bool apply_closure(CardTableEntryClosure* cl,

                     bool consume = true,

                     uint worker_i = 0);

  // Apply the closure to all elements of "buf", down to "index"

  // (inclusive.)  If returns "false", then a closure application returned

  // "false", and we return immediately.  If "consume" is true, entries are

  // set to NULL as they are processed, so they will not be processed again

  // later.

  static bool apply_closure_to_buffer(CardTableEntryClosure* cl,

                                      void** buf, size_t index, size_t sz,

                                      bool consume = true,

                                      uint worker_i = 0);

  void **get_buf() { return _buf;}

  void set_buf(void **buf) {_buf = buf;}

  size_t get_index() { return _index;}

  void reinitialize() { _buf = 0; _sz = 0; _index = 0;}

};

class DirtyCardQueueSet: public PtrQueueSet {

  // The closure used in mut_process_buffer().

  CardTableEntryClosure* _mut_process_closure;

  DirtyCardQueue _shared_dirty_card_queue;

  // Override.

  bool mut_process_buffer(void** buf);

  // Protected by the _cbl_mon.

  FreeIdSet* _free_ids;

  // The number of completed buffers processed by mutator and rs thread,

  // respectively.

  jint _processed_buffers_mut;

  jint _processed_buffers_rs_thread;

  // Current buffer node used for parallel iteration.

  BufferNode* volatile _cur_par_buffer_node;

public:

  DirtyCardQueueSet(bool notify_when_complete = true);

  void initialize(CardTableEntryClosure* cl, Monitor* cbl_mon, Mutex* fl_lock,

                  int process_completed_threshold,

                  int max_completed_queue,

                  Mutex* lock, PtrQueueSet* fl_owner = NULL);

  // The number of parallel ids that can be claimed to allow collector or

  // mutator threads to do card-processing work.

  static uint num_par_ids();

  static void handle_zero_index_for_thread(JavaThread* t);

  // Apply the given closure to all entries in all currently-active buffers.

  // This should only be applied at a safepoint. (Currently must not be called

  // in parallel; this should change in the future.)  If "consume" is true,

  // processed entries are discarded.

  void iterate_closure_all_threads(CardTableEntryClosure* cl,

                                   bool consume = true,

                                   uint worker_i = 0);

  // If there exists some completed buffer, pop it, then apply the

  // specified closure to all its elements, nulling out those elements

  // processed.  If all elements are processed, returns "true".  If no

  // completed buffers exist, returns false.  If a completed buffer exists,

  // but is only partially completed before a "yield" happens, the

  // partially completed buffer (with its processed elements set to NULL)

  // is returned to the completed buffer set, and this call returns false.

  bool apply_closure_to_completed_buffer(CardTableEntryClosure* cl,

                                         uint worker_i = 0,

                                         int stop_at = 0,

                                         bool during_pause = false);

  // Helper routine for the above.

  bool apply_closure_to_completed_buffer_helper(CardTableEntryClosure* cl,

                                                uint worker_i,

                                                BufferNode* nd);

  BufferNode* get_completed_buffer(int stop_at);

  // Applies the current closure to all completed buffers,

  // non-consumptively.

  void apply_closure_to_all_completed_buffers(CardTableEntryClosure* cl);

  void reset_for_par_iteration() { _cur_par_buffer_node = _completed_buffers_head; }

  // Applies the current closure to all completed buffers, non-consumptively.

  // Parallel version.

  void par_apply_closure_to_all_completed_buffers(CardTableEntryClosure* cl);

  DirtyCardQueue* shared_dirty_card_queue() {

    return &_shared_dirty_card_queue;

  }

  // Deallocate any completed log buffers

  void clear();

  // If a full collection is happening, reset partial logs, and ignore

  // completed ones: the full collection will make them all irrelevant.

  void abandon_logs();

  // If any threads have partial logs, add them to the global list of logs.

  void concatenate_logs();

  void clear_n_completed_buffers() { _n_completed_buffers = 0;}

  jint processed_buffers_mut() {

    return _processed_buffers_mut;

  }

  jint processed_buffers_rs_thread() {

    return _processed_buffers_rs_thread;

  }

};