mirror of
https://github.com/gnif/LookingGlass.git
synced 2026-08-22 15:11:31 +00:00
122 lines
4.0 KiB
C++
122 lines
4.0 KiB
C++
/**
|
|
* Looking Glass
|
|
* Copyright © 2017-2026 The Looking Glass Authors
|
|
* https://looking-glass.io
|
|
*
|
|
* 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 of the License, 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, Inc., 59
|
|
* Temple Place, Suite 330, Boston, MA 02111-1307 USA
|
|
*/
|
|
|
|
#include "CClipboardRing.h"
|
|
|
|
#include "Atomic.h"
|
|
|
|
#include <string.h>
|
|
|
|
void CClipboardRing::Initialize(
|
|
ClipboardMapping& mapping, uint64_t epoch)
|
|
{
|
|
memset(&mapping, 0, sizeof(mapping));
|
|
mapping.magic = LG_CLIPBOARD_MAPPING_MAGIC;
|
|
mapping.version = LG_CLIPBOARD_MAPPING_VERSION;
|
|
mapping.size = sizeof(mapping);
|
|
mapping.slotBytes = KVMFR_CLIPBOARD_DATA_BYTES;
|
|
mapping.slotCount = KVMFR_CLIPBOARD_SLOT_COUNT;
|
|
mapping.epoch = epoch;
|
|
}
|
|
|
|
bool CClipboardRing::Valid(
|
|
const ClipboardMapping& mapping, uint64_t epoch)
|
|
{
|
|
if (mapping.magic != LG_CLIPBOARD_MAPPING_MAGIC ||
|
|
mapping.version != LG_CLIPBOARD_MAPPING_VERSION ||
|
|
mapping.size != sizeof(mapping) ||
|
|
mapping.slotBytes != KVMFR_CLIPBOARD_DATA_BYTES ||
|
|
mapping.slotCount != KVMFR_CLIPBOARD_SLOT_COUNT ||
|
|
!mapping.epoch || mapping.epoch != epoch)
|
|
return false;
|
|
|
|
ClipboardRing& helper =
|
|
const_cast<ClipboardRing&>(mapping.helperToIdd);
|
|
ClipboardRing& idd =
|
|
const_cast<ClipboardRing&>(mapping.iddToHelper);
|
|
const uint32_t helperProduced = Atomic::Load(helper.produced);
|
|
const uint32_t helperConsumed = Atomic::Load(helper.consumed);
|
|
const uint32_t iddProduced = Atomic::Load(idd.produced);
|
|
const uint32_t iddConsumed = Atomic::Load(idd.consumed);
|
|
return helperProduced - helperConsumed <= KVMFR_CLIPBOARD_SLOT_COUNT &&
|
|
iddProduced - iddConsumed <= KVMFR_CLIPBOARD_SLOT_COUNT;
|
|
}
|
|
|
|
ClipboardRingSlot * CClipboardRing::BeginWrite(
|
|
ClipboardRing& ring, uint32_t& ticket)
|
|
{
|
|
const uint32_t produced = Atomic::Load(ring.produced);
|
|
const uint32_t consumed = Atomic::Load(ring.consumed);
|
|
const uint32_t pending = produced - consumed;
|
|
if (pending >= KVMFR_CLIPBOARD_SLOT_COUNT)
|
|
return nullptr;
|
|
|
|
ticket = produced;
|
|
return &ring.slots[produced % KVMFR_CLIPBOARD_SLOT_COUNT];
|
|
}
|
|
|
|
bool CClipboardRing::EndWrite(ClipboardRing& ring, uint32_t ticket)
|
|
{
|
|
if (Atomic::Load(ring.produced) != ticket)
|
|
return false;
|
|
|
|
Atomic::Fence();
|
|
Atomic::Store(ring.produced, ticket + 1U);
|
|
return true;
|
|
}
|
|
|
|
ClipboardRingReadResult CClipboardRing::BeginRead(ClipboardRing& ring,
|
|
uint32_t& ticket, const ClipboardRingSlot *& slot)
|
|
{
|
|
slot = nullptr;
|
|
const uint32_t consumed = Atomic::Load(ring.consumed);
|
|
const uint32_t pending = Atomic::Load(ring.produced) - consumed;
|
|
if (!pending)
|
|
return ClipboardRingReadResult::EMPTY;
|
|
if (pending > KVMFR_CLIPBOARD_SLOT_COUNT)
|
|
return ClipboardRingReadResult::CORRUPT;
|
|
|
|
Atomic::Fence();
|
|
ticket = consumed;
|
|
slot = &ring.slots[consumed % KVMFR_CLIPBOARD_SLOT_COUNT];
|
|
return ClipboardRingReadResult::READY;
|
|
}
|
|
|
|
bool CClipboardRing::EndRead(ClipboardRing& ring, uint32_t ticket)
|
|
{
|
|
if (Atomic::Load(ring.consumed) != ticket)
|
|
return false;
|
|
|
|
Atomic::Fence();
|
|
Atomic::Store(ring.consumed, ticket + 1U);
|
|
return true;
|
|
}
|
|
|
|
bool CClipboardRing::Valid(const ClipboardRingSlot& slot)
|
|
{
|
|
return slot.header.version == KVMFR_CLIPBOARD_VERSION &&
|
|
slot.header.type >= KVMFR_CLIPBOARD_MESSAGE_CLAIM &&
|
|
slot.header.type <= KVMFR_CLIPBOARD_MESSAGE_FILE_CANCEL &&
|
|
slot.header.length <= KVMFR_CLIPBOARD_DATA_BYTES &&
|
|
(slot.header.type == KVMFR_CLIPBOARD_MESSAGE_DATA ||
|
|
slot.header.type == KVMFR_CLIPBOARD_MESSAGE_FILE_DATA ||
|
|
!slot.header.length);
|
|
}
|