ClickHouse/libs/libzkutil/include/zkutil/Increment.h

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#pragma once
#include <zkutil/ZooKeeperHolder.h>
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namespace zkutil
{
class Increment
{
public:
Increment(ZooKeeperHolderPtr zk_holder_, const std::string & path_)
: zookeeper_holder(zk_holder_), path(path_)
{
zookeeper_holder->getZooKeeper()->createAncestors(path);
}
size_t get()
{
LOG_TRACE(log, "Get increment");
size_t result = 0;
std::string result_str;
zkutil::Stat stat;
bool success = false;
auto zookeeper = zookeeper_holder->getZooKeeper();
do
{
if (zookeeper->tryGet(path, result_str, &stat))
{
result = std::stol(result_str) + 1;
success = zookeeper->trySet(path, std::to_string(result), stat.version) == ZOK;
}
else
{
success = zookeeper->tryCreate(path, std::to_string(result), zkutil::CreateMode::Persistent) == ZOK;
}
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}
while (!success);
return result;
}
private:
zkutil::ZooKeeperHolderPtr zookeeper_holder;
std::string path;
Logger * log = &Logger::get("zkutil::Increment");
};
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}