mirror of
https://github.com/ClickHouse/ClickHouse.git
synced 2024-12-18 04:12:19 +00:00
47 lines
1.3 KiB
C++
47 lines
1.3 KiB
C++
#pragma once
|
||
|
||
#include <string>
|
||
#include <fcntl.h>
|
||
|
||
#include <DB/IO/ReadBuffer.h>
|
||
#include <DB/IO/BufferWithOwnMemory.h>
|
||
|
||
namespace DB
|
||
{
|
||
|
||
class ReadBufferFromFileBase : public BufferWithOwnMemory<ReadBuffer>
|
||
{
|
||
public:
|
||
ReadBufferFromFileBase(size_t buf_size, char * existing_memory, size_t alignment);
|
||
virtual ~ReadBufferFromFileBase();
|
||
off_t seek(off_t off, int whence = SEEK_SET);
|
||
virtual off_t getPositionInFile() = 0;
|
||
virtual std::string getFileName() const = 0;
|
||
virtual int getFD() const = 0;
|
||
|
||
/// Есть возможность получать информацию о времени каждого чтения.
|
||
struct ProfileInfo
|
||
{
|
||
size_t bytes_requested;
|
||
size_t bytes_read;
|
||
size_t nanoseconds;
|
||
};
|
||
|
||
using ProfileCallback = std::function<void(ProfileInfo)>;
|
||
|
||
/// CLOCK_MONOTONIC_COARSE более чем достаточно для отслеживания долгих чтений - например, залипаний на секунды.
|
||
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;
|
||
|
||
virtual off_t doSeek(off_t off, int whence) = 0;
|
||
};
|
||
|
||
}
|