1#pragma once
2
3#include <IO/ReadBufferFromFileDescriptor.h>
4#include <Common/CurrentMetrics.h>
5
6#ifndef O_DIRECT
7#define O_DIRECT 00040000
8#endif
9
10namespace CurrentMetrics
11{
12 extern const Metric OpenFileForRead;
13}
14
15namespace DB
16{
17
18/** Accepts path to file and opens it, or pre-opened file descriptor.
19 * Closes file by himself (thus "owns" a file descriptor).
20 */
21class ReadBufferFromFile : public ReadBufferFromFileDescriptor
22{
23protected:
24 std::string file_name;
25 CurrentMetrics::Increment metric_increment{CurrentMetrics::OpenFileForRead};
26
27public:
28 ReadBufferFromFile(const std::string & file_name_, size_t buf_size = DBMS_DEFAULT_BUFFER_SIZE, int flags = -1,
29 char * existing_memory = nullptr, size_t alignment = 0);
30
31 /// Use pre-opened file descriptor.
32 ReadBufferFromFile(int fd, const std::string & original_file_name = {}, size_t buf_size = DBMS_DEFAULT_BUFFER_SIZE,
33 char * existing_memory = nullptr, size_t alignment = 0);
34
35 ReadBufferFromFile(ReadBufferFromFile &&) = default;
36
37 ~ReadBufferFromFile() override;
38
39 /// Close file before destruction of object.
40 void close();
41
42 std::string getFileName() const override
43 {
44 return file_name;
45 }
46};
47
48}
49