ClickHouse/src/Disks/DiskDecorator.h

#pragma once

#include "Disks/IDisk.h"

namespace DB
{

/** Forwards all methods to another disk.
  * Methods can be overridden by descendants.
  */
class DiskDecorator : public IDisk
{
public:
    explicit DiskDecorator(const DiskPtr & delegate_);
    const String & getName() const override;
    ReservationPtr reserve(UInt64 bytes) override;
    ~DiskDecorator() override = default;
    const String & getPath() const override;
    UInt64 getTotalSpace() const override;
    UInt64 getAvailableSpace() const override;
    UInt64 getUnreservedSpace() const override;
    UInt64 getKeepingFreeSpace() const override;
    bool exists(const String & path) const override;
    bool isFile(const String & path) const override;
    bool isDirectory(const String & path) const override;
    size_t getFileSize(const String & path) const override;
    void createDirectory(const String & path) override;
    void createDirectories(const String & path) override;
    void clearDirectory(const String & path) override;
    void moveDirectory(const String & from_path, const String & to_path) override;
    DiskDirectoryIteratorPtr iterateDirectory(const String & path) override;
    void createFile(const String & path) override;
    void moveFile(const String & from_path, const String & to_path) override;
    void replaceFile(const String & from_path, const String & to_path) override;
    void copy(const String & from_path, const std::shared_ptr<IDisk> & to_disk, const String & to_path) override;
    void listFiles(const String & path, std::vector<String> & file_names) override;

    std::unique_ptr<ReadBufferFromFileBase> readFile(
        const String & path,
        size_t buf_size,
        size_t estimated_size,
        size_t direct_io_threshold,
        size_t mmap_threshold,
        MMappedFileCache * mmap_cache) const override;

    std::unique_ptr<WriteBufferFromFileBase> writeFile(
        const String & path,
        size_t buf_size,
        WriteMode mode) override;

    void removeFile(const String & path) override;
    void removeFileIfExists(const String & path) override;
    void removeDirectory(const String & path) override;
    void removeRecursive(const String & path) override;
    void removeSharedFile(const String & path, bool keep_s3) override;
    void removeSharedRecursive(const String & path, bool keep_s3) override;
    void setLastModified(const String & path, const Poco::Timestamp & timestamp) override;
    Poco::Timestamp getLastModified(const String & path) override;
    void setReadOnly(const String & path) override;
    void createHardLink(const String & src_path, const String & dst_path) override;
    void truncateFile(const String & path, size_t size) override;
    int open(const String & path, mode_t mode) const;
    void close(int fd) const;
    void sync(int fd) const;
    String getUniqueId(const String & path) const override { return delegate->getUniqueId(path); }
    bool checkUniqueId(const String & id) const override { return delegate->checkUniqueId(id); }
    DiskType::Type getType() const override { return delegate->getType(); }
    bool supportZeroCopyReplication() const override { return delegate->supportZeroCopyReplication(); }
    void onFreeze(const String & path) override;
    SyncGuardPtr getDirectorySyncGuard(const String & path) const override;
    void shutdown() override;
    void startup() override;
    void applyNewSettings(const Poco::Util::AbstractConfiguration & config, ContextPtr context, const String & config_prefix, const DisksMap & map) override;

protected:
    Executor & getExecutor() override;

    DiskPtr delegate;
};

/// TODO: Current reservation mechanism leaks IDisk abstraction details.
/// This hack is needed to return proper disk pointer (wrapper instead of implementation) from reservation object.
class ReservationDelegate : public IReservation
{
public:
    ReservationDelegate(ReservationPtr delegate_, DiskPtr wrapper_) : delegate(std::move(delegate_)), wrapper(wrapper_) { }
    UInt64 getSize() const override { return delegate->getSize(); }
    DiskPtr getDisk(size_t) const override { return wrapper; }
    Disks getDisks() const override { return {wrapper}; }
    void update(UInt64 new_size) override { delegate->update(new_size); }

private:
    ReservationPtr delegate;
    DiskPtr wrapper;
};


}