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#include "StarLockFile.hpp"
#include "StarTime.hpp"
#include "StarThread.hpp"
#include "StarString_windows.hpp"
#include <windows.h>
namespace Star {
int64_t const LockFile::MaximumSleepMillis;
Maybe<LockFile> LockFile::acquireLock(String const& filename, int64_t lockTimeout) {
LockFile lock(std::move(filename));
if (lock.lock(lockTimeout))
return std::move(lock);
return {};
}
LockFile::LockFile(String const& filename) : m_filename(std::move(filename)) {}
LockFile::LockFile(LockFile&& lockFile) {
operator=(std::move(lockFile));
}
LockFile::~LockFile() {
unlock();
}
LockFile& LockFile::operator=(LockFile&& lockFile) {
m_filename = std::move(lockFile.m_filename);
m_handle = std::move(lockFile.m_handle);
return *this;
}
bool LockFile::lock(int64_t timeout) {
auto doFLock = [](String const& filename) -> shared_ptr<HANDLE> {
HANDLE handle = CreateFileW(
stringToUtf16(filename).get(), GENERIC_READ, 0, nullptr, OPEN_ALWAYS, FILE_FLAG_DELETE_ON_CLOSE, nullptr);
if (handle == INVALID_HANDLE_VALUE) {
if (GetLastError() == ERROR_SHARING_VIOLATION)
return {};
throw StarException(strf("Could not open lock file {}, error code {}\n", filename, GetLastError()));
}
return make_shared<HANDLE>(handle);
};
if (timeout == 0) {
m_handle = doFLock(m_filename);
return (bool)m_handle;
} else {
int64_t startTime = Time::monotonicMilliseconds();
while (true) {
m_handle = doFLock(m_filename);
if (m_handle)
return true;
if (timeout > 0 && Time::monotonicMilliseconds() - startTime > timeout)
return false;
Thread::sleep(min(timeout / 4, MaximumSleepMillis));
}
}
}
void LockFile::unlock() {
if (m_handle) {
HANDLE handle = *(HANDLE*)m_handle.get();
CloseHandle(handle);
m_handle.reset();
}
}
bool LockFile::isLocked() const {
return (bool)m_handle;
}
}
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