95 lines
2.1 KiB
C++
95 lines
2.1 KiB
C++
#include "StarLockFile.hpp"
|
|
#include "StarTime.hpp"
|
|
#include "StarThread.hpp"
|
|
|
|
#include <sys/file.h>
|
|
#include <fcntl.h>
|
|
#include <errno.h>
|
|
#include <unistd.h>
|
|
|
|
namespace Star {
|
|
|
|
int64_t const LockFile::MaximumSleepMillis;
|
|
|
|
Maybe<LockFile> LockFile::acquireLock(String const& filename, int64_t lockTimeout) {
|
|
LockFile lock(move(filename));
|
|
if (lock.lock(lockTimeout))
|
|
return move(lock);
|
|
return {};
|
|
}
|
|
|
|
LockFile::LockFile(String const& filename) : m_filename(move(filename)) {}
|
|
|
|
LockFile::LockFile(LockFile&& lockFile) {
|
|
operator=(move(lockFile));
|
|
}
|
|
|
|
LockFile::~LockFile() {
|
|
unlock();
|
|
}
|
|
|
|
LockFile& LockFile::operator=(LockFile&& lockFile) {
|
|
m_filename = move(lockFile.m_filename);
|
|
m_handle = move(lockFile.m_handle);
|
|
|
|
return *this;
|
|
}
|
|
|
|
bool LockFile::lock(int64_t timeout) {
|
|
auto doFLock = [](String const& filename, bool block) -> shared_ptr<int> {
|
|
int fd = open(filename.utf8Ptr(), O_RDONLY | O_CREAT, 0644);
|
|
if (fd < 0)
|
|
throw StarException(strf("Could not open lock file %s, %s\n", filename, strerror(errno)));
|
|
|
|
int ret;
|
|
if (block)
|
|
ret = flock(fd, LOCK_EX);
|
|
else
|
|
ret = flock(fd, LOCK_EX | LOCK_NB);
|
|
|
|
if (ret != 0) {
|
|
close(fd);
|
|
if (errno != EWOULDBLOCK)
|
|
throw StarException(strf("Could not lock file %s, %s\n", filename, strerror(errno)));
|
|
return {};
|
|
}
|
|
|
|
return make_shared<int>(fd);
|
|
};
|
|
|
|
if (timeout < 0) {
|
|
m_handle = doFLock(m_filename, true);
|
|
return true;
|
|
} else if (timeout == 0) {
|
|
m_handle = doFLock(m_filename, false);
|
|
return (bool)m_handle;
|
|
} else {
|
|
int64_t startTime = Time::monotonicMilliseconds();
|
|
while (true) {
|
|
m_handle = doFLock(m_filename, false);
|
|
if (m_handle)
|
|
return true;
|
|
|
|
if (Time::monotonicMilliseconds() - startTime > timeout)
|
|
return false;
|
|
|
|
Thread::sleep(min(timeout / 4, MaximumSleepMillis));
|
|
}
|
|
}
|
|
}
|
|
|
|
void LockFile::unlock() {
|
|
if (m_handle) {
|
|
int fd = *(int*)m_handle.get();
|
|
unlink(m_filename.utf8Ptr());
|
|
close(fd);
|
|
m_handle.reset();
|
|
}
|
|
}
|
|
|
|
bool LockFile::isLocked() const {
|
|
return (bool)m_handle;
|
|
}
|
|
|
|
}
|