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#include "filelocks.h"
#include <utility>
#include "lockable.h"
#include "meta.h"
using namespace std;
namespace acng
{
base_with_condition g_mmapLocksMx;
decltype(TFileShrinkGuard::g_mmapLocks) TFileShrinkGuard::g_mmapLocks;
// little helper to exclude competing mmap and file shrinking operations
TFileShrinkGuard::~TFileShrinkGuard()
{
lockguard g(g_mmapLocksMx);
g_mmapLocks.erase(m_it);
g_mmapLocksMx.notifyAll();
}
unique_ptr<TFileShrinkGuard> TFileShrinkGuard::Acquire(const struct stat& info)
{
lockuniq g(g_mmapLocksMx);
while(true) {
#ifdef COMPATGCC47
auto res = g_mmapLocks.insert(make_pair(info.st_dev, info.st_ino));
#else
auto res = g_mmapLocks.emplace(info.st_dev, info.st_ino);
#endif
if(res.second) // true if freshly inserted, false if there was an entry already
{
auto ret = new TFileShrinkGuard();
ret->m_it = res.first;
return unique_ptr<TFileShrinkGuard>(ret);
}
g_mmapLocksMx.wait(g);
}
}
}
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