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64 lines
1.1 KiB
C++
64 lines
1.1 KiB
C++
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#if defined(OS_LINUX)
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#include <Common/EventFD.h>
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#include <Common/Exception.h>
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#include <sys/eventfd.h>
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#include <unistd.h>
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namespace DB
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{
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namespace ErrorCodes
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{
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extern const int CANNOT_PIPE;
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extern const int CANNOT_READ_FROM_SOCKET;
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extern const int CANNOT_WRITE_TO_SOCKET;
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}
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EventFD::EventFD()
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{
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fd = eventfd(0 /* initval */, 0 /* flags */);
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if (fd == -1)
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throwFromErrno("Cannot create eventfd", ErrorCodes::CANNOT_PIPE);
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}
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uint64_t EventFD::read() const
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{
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uint64_t buf = 0;
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while (-1 == ::read(fd, &buf, sizeof(buf)))
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{
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if (errno == EAGAIN)
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break;
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if (errno != EINTR)
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throwFromErrno("Cannot read from eventfd", ErrorCodes::CANNOT_READ_FROM_SOCKET);
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}
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return buf;
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}
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bool EventFD::write(uint64_t increase) const
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{
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while (-1 == ::write(fd, &increase, sizeof(increase)))
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{
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if (errno == EAGAIN)
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return false;
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if (errno != EINTR)
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throwFromErrno("Cannot write to eventfd", ErrorCodes::CANNOT_WRITE_TO_SOCKET);
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}
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return true;
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}
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EventFD::~EventFD()
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{
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if (fd != -1)
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close(fd);
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}
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}
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#endif
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