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// Copyright (C) 2016 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
#include "qsharedmemory.h"
#include "qsharedmemory_p.h"
#include "qsystemsemaphore.h"
#include <qdebug.h>
#include <qt_windows.h>
QT_BEGIN_NAMESPACE
using namespace Qt::StringLiterals;
#if QT_CONFIG(sharedmemory)
QSharedMemoryPrivate::QSharedMemoryPrivate() :
#ifndef QT_NO_QOBJECT
QObjectPrivate(),
#endif
memory(0), size(0), error(QSharedMemory::NoError),
systemSemaphore(QString()), lockedByMe(false), hand(0)
{
}
void QSharedMemoryPrivate::setErrorString(QLatin1StringView function)
{
DWORD windowsError = GetLastError();
if (windowsError == 0)
return;
switch (windowsError) {
case ERROR_ALREADY_EXISTS:
error = QSharedMemory::AlreadyExists;
errorString = QSharedMemory::tr("%1: already exists").arg(function);
break;
case ERROR_FILE_NOT_FOUND:
error = QSharedMemory::NotFound;
errorString = QSharedMemory::tr("%1: doesn't exist").arg(function);
break;
case ERROR_COMMITMENT_LIMIT:
error = QSharedMemory::InvalidSize;
errorString = QSharedMemory::tr("%1: invalid size").arg(function);
break;
case ERROR_NO_SYSTEM_RESOURCES:
case ERROR_NOT_ENOUGH_MEMORY:
error = QSharedMemory::OutOfResources;
errorString = QSharedMemory::tr("%1: out of resources").arg(function);
break;
case ERROR_ACCESS_DENIED:
error = QSharedMemory::PermissionDenied;
errorString = QSharedMemory::tr("%1: permission denied").arg(function);
break;
default:
errorString = QSharedMemory::tr("%1: unknown error %2").arg(function).arg(windowsError);
error = QSharedMemory::UnknownError;
#if defined QSHAREDMEMORY_DEBUG
qDebug() << errorString << "key" << key;
#endif
}
}
HANDLE QSharedMemoryPrivate::handle()
{
if (!hand) {
const auto function = "QSharedMemory::handle"_L1;
if (nativeKey.isEmpty()) {
error = QSharedMemory::KeyError;
errorString = QSharedMemory::tr("%1: unable to make key").arg(function);
return 0;
}
hand = OpenFileMapping(FILE_MAP_ALL_ACCESS, false,
reinterpret_cast<const wchar_t *>(nativeKey.utf16()));
if (!hand) {
setErrorString(function);
return 0;
}
}
return hand;
}
bool QSharedMemoryPrivate::cleanHandle()
{
if (hand != 0 && !CloseHandle(hand)) {
hand = 0;
setErrorString("QSharedMemory::cleanHandle"_L1);
return false;
}
hand = 0;
return true;
}
bool QSharedMemoryPrivate::create(qsizetype size)
{
const auto function = "QSharedMemory::create"_L1;
if (nativeKey.isEmpty()) {
error = QSharedMemory::KeyError;
errorString = QSharedMemory::tr("%1: key error").arg(function);
return false;
}
// Create the file mapping.
DWORD high, low;
if constexpr (sizeof(qsizetype) == 8)
high = DWORD(quint64(size) >> 32);
else
high = 0;
low = DWORD(size_t(size) & 0xffffffff);
hand = CreateFileMapping(INVALID_HANDLE_VALUE, 0, PAGE_READWRITE, high, low,
reinterpret_cast<const wchar_t *>(nativeKey.utf16()));
setErrorString(function);
// hand is valid when it already exists unlike unix so explicitly check
return error != QSharedMemory::AlreadyExists && hand;
}
bool QSharedMemoryPrivate::attach(QSharedMemory::AccessMode mode)
{
// Grab a pointer to the memory block
int permissions = (mode == QSharedMemory::ReadOnly ? FILE_MAP_READ : FILE_MAP_ALL_ACCESS);
memory = (void *)MapViewOfFile(handle(), permissions, 0, 0, 0);
if (0 == memory) {
setErrorString("QSharedMemory::attach"_L1);
cleanHandle();
return false;
}
// Grab the size of the memory we have been given (a multiple of 4K on windows)
MEMORY_BASIC_INFORMATION info;
if (!VirtualQuery(memory, &info, sizeof(info))) {
// Windows doesn't set an error code on this one,
// it should only be a kernel memory error.
error = QSharedMemory::UnknownError;
errorString = QSharedMemory::tr("%1: size query failed").arg("QSharedMemory::attach: "_L1);
return false;
}
size = qsizetype(info.RegionSize);
return true;
}
bool QSharedMemoryPrivate::detach()
{
// umap memory
if (!UnmapViewOfFile(memory)) {
setErrorString("QSharedMemory::detach"_L1);
return false;
}
memory = 0;
size = 0;
// close handle
return cleanHandle();
}
#endif // QT_CONFIG(sharedmemory)
QT_END_NAMESPACE
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