1 | #pragma once |
2 | |
3 | #include <Core/Types.h> |
4 | #include <Common/CurrentMetrics.h> |
5 | #include <Common/Exception.h> |
6 | |
7 | #include <memory> |
8 | #include <utility> |
9 | #include <boost/noncopyable.hpp> |
10 | |
11 | |
12 | namespace CurrentMetrics |
13 | { |
14 | extern const Metric DiskSpaceReservedForMerge; |
15 | } |
16 | |
17 | namespace DB |
18 | { |
19 | class IDiskDirectoryIterator; |
20 | using DiskDirectoryIteratorPtr = std::unique_ptr<IDiskDirectoryIterator>; |
21 | |
22 | class IReservation; |
23 | using ReservationPtr = std::unique_ptr<IReservation>; |
24 | |
25 | class ReadBuffer; |
26 | class WriteBuffer; |
27 | |
28 | /** |
29 | * Provide interface for reservation. |
30 | */ |
31 | class Space : public std::enable_shared_from_this<Space> |
32 | { |
33 | public: |
34 | /// Return the name of the space object. |
35 | virtual const String & getName() const = 0; |
36 | |
37 | /// Reserve the specified number of bytes. |
38 | virtual ReservationPtr reserve(UInt64 bytes) = 0; |
39 | |
40 | virtual ~Space() = default; |
41 | }; |
42 | |
43 | using SpacePtr = std::shared_ptr<Space>; |
44 | |
45 | /** |
46 | * A unit of storage persisting data and metadata. |
47 | * Abstract underlying storage technology. |
48 | * Responsible for: |
49 | * - file management; |
50 | * - space accounting and reservation. |
51 | */ |
52 | class IDisk : public Space |
53 | { |
54 | public: |
55 | /// Root path for all files stored on the disk. |
56 | /// It's not required to be a local filesystem path. |
57 | virtual const String & getPath() const = 0; |
58 | |
59 | /// Total available space on the disk. |
60 | virtual UInt64 getTotalSpace() const = 0; |
61 | |
62 | /// Space currently available on the disk. |
63 | virtual UInt64 getAvailableSpace() const = 0; |
64 | |
65 | /// Space available for reservation (available space minus reserved space). |
66 | virtual UInt64 getUnreservedSpace() const = 0; |
67 | |
68 | /// Amount of bytes which should be kept free on the disk. |
69 | virtual UInt64 getKeepingFreeSpace() const { return 0; } |
70 | |
71 | /// Return `true` if the specified file exists. |
72 | virtual bool exists(const String & path) const = 0; |
73 | |
74 | /// Return `true` if the specified file exists and it's a regular file (not a directory or special file type). |
75 | virtual bool isFile(const String & path) const = 0; |
76 | |
77 | /// Return `true` if the specified file exists and it's a directory. |
78 | virtual bool isDirectory(const String & path) const = 0; |
79 | |
80 | /// Create directory. |
81 | virtual void createDirectory(const String & path) = 0; |
82 | |
83 | /// Create directory and all parent directories if necessary. |
84 | virtual void createDirectories(const String & path) = 0; |
85 | |
86 | /// Return iterator to the contents of the specified directory. |
87 | virtual DiskDirectoryIteratorPtr iterateDirectory(const String & path) = 0; |
88 | |
89 | /// Move the file from `from_path` to `to_path`. |
90 | virtual void moveFile(const String & from_path, const String & to_path) = 0; |
91 | |
92 | /// Copy the file from `from_path` to `to_path`. |
93 | virtual void copyFile(const String & from_path, const String & to_path) = 0; |
94 | |
95 | /// Open the file for read and return ReadBuffer object. |
96 | virtual std::unique_ptr<ReadBuffer> readFile(const String & path) const = 0; |
97 | |
98 | /// Open the file for write and return WriteBuffer object. |
99 | virtual std::unique_ptr<WriteBuffer> writeFile(const String & path) = 0; |
100 | }; |
101 | |
102 | using DiskPtr = std::shared_ptr<IDisk>; |
103 | using Disks = std::vector<DiskPtr>; |
104 | |
105 | /** |
106 | * Iterator of directory contents on particular disk. |
107 | */ |
108 | class IDiskDirectoryIterator |
109 | { |
110 | public: |
111 | /// Iterate to the next file. |
112 | virtual void next() = 0; |
113 | |
114 | /// Return `true` if the iterator points to a valid element. |
115 | virtual bool isValid() const = 0; |
116 | |
117 | /// Name of the file that the iterator currently points to. |
118 | virtual String name() const = 0; |
119 | |
120 | virtual ~IDiskDirectoryIterator() = default; |
121 | }; |
122 | |
123 | /** |
124 | * Information about reserved size on particular disk. |
125 | */ |
126 | class IReservation |
127 | { |
128 | public: |
129 | /// Get reservation size. |
130 | virtual UInt64 getSize() const = 0; |
131 | |
132 | /// Get disk where reservation take place. |
133 | virtual DiskPtr getDisk() const = 0; |
134 | |
135 | /// Changes amount of reserved space. |
136 | virtual void update(UInt64 new_size) = 0; |
137 | |
138 | /// Unreserves reserved space. |
139 | virtual ~IReservation() = default; |
140 | }; |
141 | |
142 | /// Return full path to a file on disk. |
143 | inline String fullPath(const DiskPtr & disk, const String & path) |
144 | { |
145 | return disk->getPath() + path; |
146 | } |
147 | |
148 | } |
149 | |