ClickHouse/src/Access/DiskAccessStorage.h

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#pragma once
#include <Access/MemoryAccessStorage.h>
#include <Common/ThreadPool.h>
#include <boost/container/flat_set.hpp>
namespace DB
{
/// Loads and saves access entities on a local disk to a specified directory.
class DiskAccessStorage : public IAccessStorage
{
public:
static constexpr char STORAGE_TYPE[] = "local directory";
DiskAccessStorage(const String & storage_name_, const String & directory_path_, bool readonly_ = false);
DiskAccessStorage(const String & directory_path_, bool readonly_ = false);
~DiskAccessStorage() override;
const char * getStorageType() const override { return STORAGE_TYPE; }
String getStoragePath() const override { return directory_path; }
bool isStoragePathEqual(const String & directory_path_) const;
void setReadOnly(bool readonly_) { readonly = readonly_; }
bool isStorageReadOnly() const override { return readonly; }
private:
std::optional<UUID> findImpl(EntityType type, const String & name) const override;
std::vector<UUID> findAllImpl(EntityType type) const override;
bool existsImpl(const UUID & id) const override;
AccessEntityPtr readImpl(const UUID & id) const override;
String readNameImpl(const UUID & id) const override;
bool canInsertImpl(const AccessEntityPtr & entity) const override;
UUID insertImpl(const AccessEntityPtr & entity, bool replace_if_exists) override;
void removeImpl(const UUID & id) override;
void updateImpl(const UUID & id, const UpdateFunc & update_func) override;
ext::scope_guard subscribeForChangesImpl(const UUID & id, const OnChangedHandler & handler) const override;
ext::scope_guard subscribeForChangesImpl(EntityType type, const OnChangedHandler & handler) const override;
bool hasSubscriptionImpl(const UUID & id) const override;
bool hasSubscriptionImpl(EntityType type) const override;
void clear();
bool readLists();
bool writeLists();
void scheduleWriteLists(EntityType type);
bool rebuildLists();
void listsWritingThreadFunc();
void stopListsWritingThread();
void insertNoLock(const UUID & id, const AccessEntityPtr & new_entity, bool replace_if_exists, Notifications & notifications);
void removeNoLock(const UUID & id, Notifications & notifications);
void updateNoLock(const UUID & id, const UpdateFunc & update_func, Notifications & notifications);
AccessEntityPtr readAccessEntityFromDisk(const UUID & id) const;
void writeAccessEntityToDisk(const UUID & id, const IAccessEntity & entity) const;
void deleteAccessEntityOnDisk(const UUID & id) const;
using NameToIDMap = std::unordered_map<String, UUID>;
struct Entry
{
UUID id;
String name;
EntityType type;
mutable AccessEntityPtr entity; /// may be nullptr, if the entity hasn't been loaded yet.
mutable std::list<OnChangedHandler> handlers_by_id;
};
void prepareNotifications(const UUID & id, const Entry & entry, bool remove, Notifications & notifications) const;
String directory_path;
std::atomic<bool> readonly;
std::unordered_map<UUID, Entry> entries_by_id;
std::unordered_map<std::string_view, Entry *> entries_by_name_and_type[static_cast<size_t>(EntityType::MAX)];
boost::container::flat_set<EntityType> types_of_lists_to_write;
bool failed_to_write_lists = false; /// Whether writing of the list files has been failed since the recent restart of the server.
ThreadFromGlobalPool lists_writing_thread; /// List files are written in a separate thread.
std::condition_variable lists_writing_thread_should_exit; /// Signals `lists_writing_thread` to exit.
bool lists_writing_thread_is_waiting = false;
mutable std::list<OnChangedHandler> handlers_by_type[static_cast<size_t>(EntityType::MAX)];
mutable std::mutex mutex;
};
}