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/* Distributed under the OSI-approved BSD 3-Clause License. See accompanying
file LICENSE.rst or https://cmake.org/licensing for details. */
#include <cm/memory>
#include <windows.h>
#include "cmFileLock.h"
#include "cmSystemTools.h"
static unsigned long const LOCK_LEN = static_cast<unsigned long>(-1);
cmFileLock::cmFileLock()
: Overlapped(cm::make_unique<OVERLAPPED>())
{
ZeroMemory(this->Overlapped.get(), sizeof(*this->Overlapped));
}
cmFileLockResult cmFileLock::Release()
{
if (this->Filename.empty()) {
return cmFileLockResult::MakeOk();
}
const DWORD reserved = 0;
ZeroMemory(this->Overlapped.get(), sizeof(*this->Overlapped));
const BOOL unlockResult =
UnlockFileEx(File, reserved, LOCK_LEN, LOCK_LEN, this->Overlapped.get());
this->Filename = "";
CloseHandle(this->File);
this->File = INVALID_HANDLE_VALUE;
if (unlockResult) {
return cmFileLockResult::MakeOk();
} else {
return cmFileLockResult::MakeSystem();
}
}
cmFileLockResult cmFileLock::OpenFile()
{
const DWORD access = GENERIC_READ | GENERIC_WRITE;
const DWORD shareMode = FILE_SHARE_READ | FILE_SHARE_WRITE;
const PSECURITY_ATTRIBUTES security = nullptr;
const DWORD attr = 0;
const HANDLE templ = nullptr;
this->File = CreateFileW(
cmSystemTools::ConvertToWindowsExtendedPath(this->Filename).c_str(),
access, shareMode, security, OPEN_EXISTING, attr, templ);
if (this->File == INVALID_HANDLE_VALUE) {
return cmFileLockResult::MakeSystem();
} else {
return cmFileLockResult::MakeOk();
}
}
cmFileLockResult cmFileLock::LockWithoutTimeout()
{
cmFileLockResult lock_result = cmFileLockResult::MakeOk();
if (!this->LockFile(LOCKFILE_EXCLUSIVE_LOCK)) {
lock_result = cmFileLockResult::MakeSystem();
}
CloseHandle(this->Overlapped->hEvent);
return lock_result;
}
cmFileLockResult cmFileLock::LockWithTimeout(unsigned long seconds)
{
cmFileLockResult lock_result = cmFileLockResult::MakeOk();
const DWORD flags = LOCKFILE_EXCLUSIVE_LOCK | LOCKFILE_FAIL_IMMEDIATELY;
bool in_time = true;
while (in_time && !this->LockFile(flags)) {
switch (GetLastError()) {
case ERROR_INVALID_HANDLE:
lock_result = cmFileLockResult::MakeSystem();
break;
case ERROR_LOCK_VIOLATION:
if (seconds == 0) {
in_time = false;
lock_result = cmFileLockResult::MakeTimeout();
continue;
}
--seconds;
cmSystemTools::Delay(1000);
continue;
case ERROR_IO_PENDING:
switch (
WaitForSingleObject(this->Overlapped->hEvent, seconds * 1000)) {
case WAIT_OBJECT_0:
break;
case WAIT_TIMEOUT:
lock_result = cmFileLockResult::MakeTimeout();
break;
default:
lock_result = cmFileLockResult::MakeSystem();
break;
}
break;
default:
lock_result = cmFileLockResult::MakeSystem();
break;
}
}
CloseHandle(this->Overlapped->hEvent);
return lock_result;
}
int cmFileLock::LockFile(int flags)
{
const DWORD reserved = 0;
this->Overlapped->hEvent = CreateEvent(nullptr, TRUE, FALSE, nullptr);
if (this->Overlapped->hEvent == nullptr) {
return false;
}
return LockFileEx(this->File, flags, reserved, LOCK_LEN, LOCK_LEN,
this->Overlapped.get());
}
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