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#pragma once
#include <Storages/FileLog/DirectoryWatcherBase.h>
#include <memory>
#include <mutex>
namespace DB
{
class StorageFileLog;
class FileLogDirectoryWatcher
{
public:
struct EventInfo
{
DirectoryWatcherBase::DirectoryEventType type;
std::string callback;
};
struct FileEvents
{
bool received_modification_event = false;
std::vector<EventInfo> file_events;
};
using Events = std::unordered_map<std::string, FileEvents>;
struct Error
{
bool has_error = false;
std::string error_msg = {};
};
FileLogDirectoryWatcher(const std::string & path_, StorageFileLog & storage_, ContextPtr context_);
~FileLogDirectoryWatcher() = default;
Events getEventsAndReset();
Error getErrorAndReset();
const std::string & getPath() const;
private:
friend class DirectoryWatcherBase;
/// Here must pass by value, otherwise will lead to stack-use-of-scope.
void onItemAdded(DirectoryWatcherBase::DirectoryEvent ev);
void onItemRemoved(DirectoryWatcherBase::DirectoryEvent ev);
void onItemModified(DirectoryWatcherBase::DirectoryEvent ev);
void onItemMovedFrom(DirectoryWatcherBase::DirectoryEvent ev);
void onItemMovedTo(DirectoryWatcherBase::DirectoryEvent ev);
void onError(Exception);
const std::string path;
StorageFileLog & storage;
/// Note, in order to avoid data race found by fuzzer, put events before dw,
/// such that when this class destruction, dw will be destructed before events.
/// The data race is because dw create a separate thread to monitor file events
/// and put into events, then if we destruct events first, the monitor thread still
/// running, it may access events during events destruction, leads to data race.
/// And we should put other members before dw as well, because all of them can be
/// accessed in thread created by dw.
Events events;
Poco::Logger * log;
std::mutex mutex;
Error error;
std::unique_ptr<DirectoryWatcherBase> dw;
};
}
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