/*
   Copyright (c) 2003, 2010, Oracle and/or its affiliates. All rights reserved.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; version 2 of the License.

   This program 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 for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA
*/

#define DBTUP_C
#define DBTUP_FIXALLOC_CPP
#include "Dbtup.hpp"
#include <RefConvert.hpp>
#include <ndb_limits.h>
#include <pc.hpp>

//
// Fixed Allocator
// This module is used to allocate and free fixed size tuples from the
// set of pages attached to a fragment. The fixed size is preset per
// fragment and their can only be one such value per fragment in the
// current implementation.
// 
// Public methods
// bool
// alloc_fix_rec(Fragrecord* const regFragPtr, # In
//               Tablerec* const regTabPtr,    # In
//               Uint32 pageType,              # In
//               Signal* signal,               # In
//               Uint32& pageOffset,           # Out
//               PagePtr& pagePtr)             # In/Out
// This method allocates a fixed size and the pagePtr is a reference
// to the page and pageOffset is the offset in the page of the tuple.
//
// freeTh()
// This method is used to free a tuple header in normal transaction
// handling.
//
// getThAtPageSr()
// This method is used to allocate a tuple on a set page as part of
// undo log execution.
//
//
// Private methods
// getThAtPage()
// This method gets a tuple from a page with free tuples.
//
// convertThPage()
// Convert an empty page into a page of free tuples in a linked list.
//
// getEmptyPageTh()
// A page recently taken from the set of empty pages on the fragment is
// is made part of the set of free pages with fixed size tuples in the
// fragment.
// 
Uint32*
Dbtup::alloc_fix_rec(Uint32 * err,
                     Fragrecord* const regFragPtr,
		     Tablerec* const regTabPtr,
		     Local_key* key,
		     Uint32 * out_frag_page_id) 
{
/* ---------------------------------------------------------------- */
/*       EITHER NORMAL PAGE REQUESTED OR ALLOCATION FROM COPY PAGE  */
/*       FAILED. TRY ALLOCATING FROM NORMAL PAGE.                   */
/* ---------------------------------------------------------------- */
  PagePtr pagePtr;
  pagePtr.i = regFragPtr->thFreeFirst.firstItem;
  if (pagePtr.i == RNIL) {
/* ---------------------------------------------------------------- */
// No prepared tuple header page with free entries exists.
/* ---------------------------------------------------------------- */
    pagePtr.i = allocFragPage(err, regFragPtr);
    if (pagePtr.i != RNIL) {
      jam();
/* ---------------------------------------------------------------- */
// We found empty pages on the fragment. Allocate an empty page and
// convert it into a tuple header page and put it in thFreeFirst-list.
/* ---------------------------------------------------------------- */
      c_page_pool.getPtr(pagePtr);

      convertThPage((Fix_page*)pagePtr.p, regTabPtr, MM);
      pagePtr.p->page_state = ZTH_MM_FREE;
      
      LocalDLFifoList<Page> free_pages(c_page_pool, regFragPtr->thFreeFirst);
      free_pages.addFirst(pagePtr);
    } else {
      jam();
/* ---------------------------------------------------------------- */
/*       THERE ARE NO EMPTY PAGES. MEMORY CAN NOT BE ALLOCATED.     */
/* ---------------------------------------------------------------- */
      return 0;
    }
  } else {
    jam();
/* ---------------------------------------------------------------- */
/*       THIS SHOULD BE THE COMMON PATH THROUGH THE CODE, FREE      */
/*       COPY PAGE EXISTED.                                         */
/* ---------------------------------------------------------------- */
    c_page_pool.getPtr(pagePtr);
  }

  Uint32 page_offset= alloc_tuple_from_page(regFragPtr, (Fix_page*)pagePtr.p);
  
  *out_frag_page_id= pagePtr.p->frag_page_id;
  key->m_page_no = pagePtr.i;
  key->m_page_idx = page_offset;
  return pagePtr.p->m_data + page_offset;
}

void Dbtup::convertThPage(Fix_page* regPagePtr,
			  Tablerec* regTabPtr,
			  Uint32 mm) 
{
  Uint32 nextTuple = regTabPtr->m_offsets[mm].m_fix_header_size;
  /*
  ASSUMES AT LEAST ONE TUPLE HEADER FITS AND THEREFORE NO HANDLING
  OF ZERO AS EXTREME CASE
  */
  Uint32 cnt= 0;
  Uint32 pos= 0;
  Uint32 prev = 0xFFFF;
#ifdef VM_TRACE
  memset(regPagePtr->m_data, 0xF1, 4*Fix_page::DATA_WORDS);
#endif
  Uint32 gci_pos = 2;
  Uint32 gci_val = 0xF1F1F1F1;
  if (regTabPtr->m_bits & Tablerec::TR_RowGCI)
  {
    Tuple_header* ptr = 0;
    gci_pos = Uint32(ptr->get_mm_gci(regTabPtr) - (Uint32*)ptr);
    gci_val = 0;
  }
  while (pos + nextTuple <= Fix_page::DATA_WORDS)
  {
    regPagePtr->m_data[pos] = (prev << 16) | (pos + nextTuple);
    regPagePtr->m_data[pos + 1] = Fix_page::FREE_RECORD;
    regPagePtr->m_data[pos + gci_pos] = gci_val;
    prev = pos;
    pos += nextTuple;
    cnt ++;
  } 
  
  regPagePtr->m_data[prev] |= 0xFFFF;
  regPagePtr->next_free_index= 0;
  regPagePtr->free_space= cnt;
  regPagePtr->m_page_header.m_page_type = File_formats::PT_Tup_fixsize_page;
}//Dbtup::convertThPage()

Uint32
Dbtup::alloc_tuple_from_page(Fragrecord* const regFragPtr,
			     Fix_page* const regPagePtr)
{
  ndbassert(regPagePtr->free_space);
  Uint32 idx= regPagePtr->alloc_record();
  if(regPagePtr->free_space == 0)
  {
    jam();
/* ---------------------------------------------------------------- */
/*       THIS WAS THE LAST TUPLE HEADER IN THIS PAGE. REMOVE IT FROM*/
/*       THE TUPLE HEADER FREE LIST OR TH COPY FREE LIST. ALSO SET  */
/*       A PROPER PAGE STATE.                                       */
/*                                                                  */
/*       WE ALSO HAVE TO INSERT AN UNDO LOG ENTRY TO ENSURE PAGE    */
/*       ARE MAINTAINED EVEN AFTER A SYSTEM CRASH.                  */
/* ---------------------------------------------------------------- */
    ndbrequire(regPagePtr->page_state == ZTH_MM_FREE);
    LocalDLFifoList<Page> free_pages(c_page_pool, regFragPtr->thFreeFirst);    
    free_pages.remove((Page*)regPagePtr);
    regPagePtr->page_state = ZTH_MM_FULL;
  }
  
  return idx;
}//Dbtup::getThAtPage()


void Dbtup::free_fix_rec(Fragrecord* regFragPtr,
			 Tablerec* regTabPtr,
			 Local_key* key,
			 Fix_page* regPagePtr)
{
  Uint32 free= regPagePtr->free_record(key->m_page_idx);
  PagePtr pagePtr = { (Page*)regPagePtr, key->m_page_no };
  
  if(free == 1)
  {
    jam();
    LocalDLFifoList<Page> free_pages(c_page_pool, regFragPtr->thFreeFirst);    
    ndbrequire(regPagePtr->page_state == ZTH_MM_FULL);
    regPagePtr->page_state = ZTH_MM_FREE;
    free_pages.addLast(pagePtr);
  } 
  else if (free == 
           (Fix_page::DATA_WORDS / regTabPtr->m_offsets[MM].m_fix_header_size))
  {
    jam();
    Uint32 page_no = pagePtr.p->frag_page_id;
    LocalDLFifoList<Page> free_pages(c_page_pool, regFragPtr->thFreeFirst);    
    free_pages.remove(pagePtr);
    releaseFragPage(regFragPtr, page_no, pagePtr);
  }
}//Dbtup::freeTh()

Uint32*
Dbtup::alloc_fix_rowid(Uint32 * err,
                       Fragrecord* regFragPtr,
		       Tablerec* regTabPtr,
		       Local_key* key,
		       Uint32 * out_frag_page_id) 
{
  Uint32 page_no = key->m_page_no;
  Uint32 idx= key->m_page_idx;
  
  PagePtr pagePtr;
  if ((pagePtr.i = allocFragPage(err, regTabPtr, regFragPtr, page_no)) == RNIL)
  {
    return 0;
  }

  c_page_pool.getPtr(pagePtr);
  Uint32 state = pagePtr.p->page_state;
  LocalDLFifoList<Page> free_pages(c_page_pool, regFragPtr->thFreeFirst);
  switch(state){
  case ZTH_MM_FREE:
    if (((Fix_page*)pagePtr.p)->alloc_record(idx) != idx)
    {
      * err = ZROWID_ALLOCATED;
      return 0;
    }
    
    if(pagePtr.p->free_space == 0)
    {
      jam();
      pagePtr.p->page_state = ZTH_MM_FULL;
      free_pages.remove(pagePtr);
    }
    
    *out_frag_page_id= page_no;
    key->m_page_no = pagePtr.i;
    key->m_page_idx = idx;
    return pagePtr.p->m_data + idx;
  case ZTH_MM_FULL:
    * err = ZROWID_ALLOCATED;
    return 0;
  default:
    ndbrequire(false);
  }
  return 0;                                     /* purify: deadcode */
}
