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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 "qv4compilationunitmapper_p.h"
#include <private/qv4compileddata_p.h>
#include <QtCore/qdatetime.h>
#include <QtCore/qfileinfo.h>
#include <QtCore/qscopeguard.h>
#include <qt_windows.h>
QT_BEGIN_NAMESPACE
using namespace QV4;
CompiledData::Unit *CompilationUnitMapper::open(const QString &cacheFileName, const QDateTime &sourceTimeStamp, QString *errorString)
{
close();
// ### TODO: fix up file encoding/normalization/unc handling once QFileSystemEntry
// is exported from QtCore.
HANDLE handle =
CreateFile(reinterpret_cast<const wchar_t*>(cacheFileName.constData()),
GENERIC_READ | GENERIC_EXECUTE, FILE_SHARE_READ,
nullptr, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL,
nullptr);
if (handle == INVALID_HANDLE_VALUE) {
*errorString = qt_error_string(GetLastError());
return nullptr;
}
auto fileHandleCleanup = qScopeGuard([handle]{
CloseHandle(handle);
});
CompiledData::Unit header;
DWORD bytesRead;
if (!ReadFile(handle, reinterpret_cast<char *>(&header), sizeof(header), &bytesRead, nullptr)) {
*errorString = qt_error_string(GetLastError());
return nullptr;
}
if (bytesRead != sizeof(header)) {
*errorString = QStringLiteral("File too small for the header fields");
return nullptr;
}
if (!header.verifyHeader(sourceTimeStamp, errorString))
return nullptr;
// Data structure and qt version matched, so now we can access the rest of the file safely.
/* Error out early on file corruption. We assume we can read header.unitSize bytes
later (even before verifying the checksum), potentially causing out-of-bound
reads
Also, no need to wait until checksum verification if we know beforehand
that the cached unit is bogus
*/
LARGE_INTEGER fileSize;
if (!GetFileSizeEx(handle, &fileSize)) {
*errorString = QStringLiteral("Could not determine file size");
return nullptr;
}
if (header.unitSize != fileSize.QuadPart) {
*errorString = QStringLiteral("Potential file corruption, file too small");
return nullptr;
}
HANDLE fileMappingHandle = CreateFileMapping(handle, 0, PAGE_READONLY, 0, 0, 0);
if (!fileMappingHandle) {
*errorString = qt_error_string(GetLastError());
return nullptr;
}
auto mappingCleanup = qScopeGuard([fileMappingHandle]{
CloseHandle(fileMappingHandle);
});
dataPtr = MapViewOfFile(fileMappingHandle, FILE_MAP_READ, 0, 0, 0);
if (!dataPtr) {
*errorString = qt_error_string(GetLastError());
return nullptr;
}
return reinterpret_cast<CompiledData::Unit*>(dataPtr);
}
void CompilationUnitMapper::close()
{
if (dataPtr != nullptr) {
// Do not unmap cache files that are built with the StaticData flag. That's the majority of
// them and it's necessary to benefit from the QString literal optimization. There might
// still be QString instances around that point into that memory area. The memory is backed
// on the disk, so the kernel is free to release the pages and all that remains is the
// address space allocation.
if (!(reinterpret_cast<CompiledData::Unit*>(dataPtr)->flags & CompiledData::Unit::StaticData))
UnmapViewOfFile(dataPtr);
}
dataPtr = nullptr;
}
QT_END_NAMESPACE
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