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 | |
10 | namespace CurrentMetrics |
11 | { |
12 | extern const Metric OpenFileForRead; |
13 | } |
14 | |
15 | namespace 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 | */ |
21 | class ReadBufferFromFile : public ReadBufferFromFileDescriptor |
22 | { |
23 | protected: |
24 | std::string file_name; |
25 | CurrentMetrics::Increment metric_increment{CurrentMetrics::OpenFileForRead}; |
26 | |
27 | public: |
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 | |