1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/libfsserver/lib/pages/pages.cc Thu Apr 15 23:15:17 2021 +0200
1.3 @@ -0,0 +1,89 @@
1.4 +/*
1.5 + * A page collection abstraction providing pages from a queue to users.
1.6 + *
1.7 + * Copyright (C) 2021 Paul Boddie <paul@boddie.org.uk>
1.8 + *
1.9 + * This program is free software; you can redistribute it and/or
1.10 + * modify it under the terms of the GNU General Public License as
1.11 + * published by the Free Software Foundation; either version 2 of
1.12 + * the License, or (at your option) any later version.
1.13 + *
1.14 + * This program is distributed in the hope that it will be useful,
1.15 + * but WITHOUT ANY WARRANTY; without even the implied warranty of
1.16 + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
1.17 + * GNU General Public License for more details.
1.18 + *
1.19 + * You should have received a copy of the GNU General Public License
1.20 + * along with this program; if not, write to the Free Software
1.21 + * Foundation, Inc., 51 Franklin Street, Fifth Floor,
1.22 + * Boston, MA 02110-1301, USA
1.23 + */
1.24 +
1.25 +#include <mem/memory_incremental.h>
1.26 +
1.27 +#include "pages.h"
1.28 +
1.29 +
1.30 +
1.31 +Pages::Pages(Memory *memory, PageQueue *queue)
1.32 +: _memory(memory), _queue(queue)
1.33 +{
1.34 +}
1.35 +
1.36 +Pages::~Pages()
1.37 +{
1.38 + _queue->close(_memory);
1.39 +}
1.40 +
1.41 +/* Remove the first flexpage in the queue. If its owner exists, remove it from
1.42 + the owner (retiring the content). Return the flexpage for reuse. */
1.43 +
1.44 +Flexpage *Pages::remove()
1.45 +{
1.46 + PageOwner *owner;
1.47 + Flexpage *flexpage;
1.48 +
1.49 + _queue->pop(&owner, &flexpage);
1.50 +
1.51 + if (owner != NULL)
1.52 + owner->remove(flexpage);
1.53 +
1.54 + return flexpage;
1.55 +}
1.56 +
1.57 +/* Reserve 'flexpage' by removing it from this collection. */
1.58 +
1.59 +bool Pages::reserve(PageOwner *owner, Flexpage *flexpage)
1.60 +{
1.61 + return _queue->remove(owner, flexpage);
1.62 +}
1.63 +
1.64 +/* Obtain a new flexpage. Return the flexpage or None if no new flexpage could
1.65 + be created. */
1.66 +
1.67 +Flexpage *Pages::flexpage()
1.68 +{
1.69 + Region *region = _memory->region();
1.70 +
1.71 + if (region != NULL)
1.72 + return new Flexpage(region);
1.73 + else
1.74 + return NULL;
1.75 +}
1.76 +
1.77 +/* Queue an entry associating the given 'owner' and 'flexpage'. */
1.78 +
1.79 +void Pages::queue(PageOwner *owner, Flexpage *flexpage)
1.80 +{
1.81 + _queue->push(owner, flexpage);
1.82 +}
1.83 +
1.84 +/* Push an entry for 'flexpage' without owner association for immediate
1.85 + reuse. */
1.86 +
1.87 +void Pages::release(Flexpage *flexpage)
1.88 +{
1.89 + _queue->push_front(NULL, flexpage);
1.90 +}
1.91 +
1.92 +// vim: tabstop=4 expandtab shiftwidth=4