kern_objectsource.cxx

C++ 编写的EROS RTOS

/*
 * Copyright (C) 1998, 1999, Jonathan S. Shapiro.
 *
 * This file is part of the EROS Operating System.
 *
 * 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; either version 2,
 * or (at your option) any later version.
 *
 * 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, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

#include <kerninc/kernel.hxx>
#include <disk/DiskKey.hxx>
#include <disk/LowVolume.hxx>
#include <kerninc/BootInfo.h>
#include <kerninc/Node.hxx>
#include <kerninc/ObjectSource.hxx>

#include <kerninc/Thread.hxx>

ObCacheSource::ObCacheSource()
  :ObjectSource("obcache", 0llu, ~0llu)
{
}

ObjectHeader *
ObCacheSource::GetObject(OID oid, ObType::Type obType, 
			 ObCount count, bool useCount)
{
  ObjectHeader *pObj = 0;

  if (obType == ObType::NtUnprepared) {
    pObj = ObjectHeader::Lookup(ObType::NtUnprepared, oid);
    assertex(pObj, (pObj == 0) || ((Node *) pObj)->Validate());
  }
  else {
    pObj = ObjectHeader::Lookup(ObType::PtDataPage, oid);
  }

  return pObj;
}

bool
ObCacheSource::WriteBack(ObjectHeader *pObj, bool inBackground)
{
  return false;
}


bool
ObCacheSource::Invalidate(ObjectHeader *pObj)
{
  return false;
}

bool
ObCacheSource::Detach()
{
  fatal("ObCacheSource::Detach(): cannot detach object cache!\n");

  return false;
}


ObjectSource::ObjectSource(const char *nm, OID first, OID last)
{
  name = nm;
  start = first;
  end = last;
}

bool
ObjectSource::IsRemovable(ObjectHeader *)
{
  /* Until proven otherwise: */
  return false;
}

/* A source can publish an incompletely populated OID range. For
 * example, the user source claims the entire persistent OID range,
 * but the machine is unlikely to have that much disk space actually
 * attached.
 *
 * For most in-kernel sources (ROM, Preload), the claimed range is the
 * real range, so it's useful to have a "generic" implementation
 * here. The exceptional case is the ResidentRange, because the number
 * of available resident frames can change as the kernel dynamically
 * (de)allocates memory.
 *
 * FIX: Perhaps this is a bug and we should implement a separate
 * persistent source for each range?
 */
void 
ObjectSource::FindFirstSubrange(OID limStart, OID limEnd,
				OID& subStart, OID& subEnd)
{
  /* Validate that the requested range and this source really do
   * overlap:
   */
  assert (end >= limStart && start < limEnd);

  /* We shouldn't have been called unless we might have a better
   * answer: 
   */

  assert(start < subStart);

  subStart = max(start, limStart);
  subEnd = min(end, limEnd);
}