ClickHouse/src/IO/ReadBufferFromFileBase.h
2020-07-31 17:53:41 +03:00

46 lines
1.1 KiB
C++

#pragma once
#include <IO/BufferWithOwnMemory.h>
#include <IO/SeekableReadBuffer.h>
#include <common/time.h>
#include <functional>
#include <string>
#include <fcntl.h>
namespace DB
{
class ReadBufferFromFileBase : public BufferWithOwnMemory<SeekableReadBuffer>
{
public:
ReadBufferFromFileBase();
ReadBufferFromFileBase(size_t buf_size, char * existing_memory, size_t alignment);
~ReadBufferFromFileBase() override;
virtual std::string getFileName() const = 0;
/// It is possible to get information about the time of each reading.
struct ProfileInfo
{
size_t bytes_requested;
size_t bytes_read;
size_t nanoseconds;
};
using ProfileCallback = std::function<void(ProfileInfo)>;
/// CLOCK_MONOTONIC_COARSE is more than enough to track long reads - for example, hanging for a second.
void setProfileCallback(const ProfileCallback & profile_callback_, clockid_t clock_type_ = CLOCK_MONOTONIC_COARSE)
{
profile_callback = profile_callback_;
clock_type = clock_type_;
}
protected:
ProfileCallback profile_callback;
clockid_t clock_type{};
};
}