1 | #pragma once |
2 | |
3 | #include <algorithm> |
4 | #include <Core/Block.h> |
5 | #include <Columns/IColumn.h> |
6 | #include <boost/smart_ptr/intrusive_ptr.hpp> |
7 | |
8 | |
9 | namespace DB |
10 | { |
11 | |
12 | /// Allows you refer to the row in the block and hold the block ownership, |
13 | /// and thus avoid creating a temporary row object. |
14 | /// Do not use std::shared_ptr, since there is no need for a place for `weak_count` and `deleter`; |
15 | /// does not use Poco::SharedPtr, since you need to allocate a block and `refcount` in one piece; |
16 | /// does not use Poco::AutoPtr, since it does not have a `move` constructor and there are extra checks for nullptr; |
17 | /// The reference counter is not atomic, since it is used from one thread. |
18 | namespace detail |
19 | { |
20 | struct SharedBlock : Block |
21 | { |
22 | int refcount = 0; |
23 | |
24 | ColumnRawPtrs all_columns; |
25 | ColumnRawPtrs sort_columns; |
26 | |
27 | SharedBlock(Block && block) : Block(std::move(block)) {} |
28 | }; |
29 | } |
30 | |
31 | inline void intrusive_ptr_add_ref(detail::SharedBlock * ptr) |
32 | { |
33 | ++ptr->refcount; |
34 | } |
35 | |
36 | inline void intrusive_ptr_release(detail::SharedBlock * ptr) |
37 | { |
38 | if (0 == --ptr->refcount) |
39 | delete ptr; |
40 | } |
41 | |
42 | using SharedBlockPtr = boost::intrusive_ptr<detail::SharedBlock>; |
43 | |
44 | struct SharedBlockRowRef |
45 | { |
46 | ColumnRawPtrs * columns = nullptr; |
47 | size_t row_num; |
48 | SharedBlockPtr shared_block; |
49 | |
50 | void swap(SharedBlockRowRef & other) |
51 | { |
52 | std::swap(columns, other.columns); |
53 | std::swap(row_num, other.row_num); |
54 | std::swap(shared_block, other.shared_block); |
55 | } |
56 | |
57 | /// The number and types of columns must match. |
58 | bool operator==(const SharedBlockRowRef & other) const |
59 | { |
60 | size_t size = columns->size(); |
61 | for (size_t i = 0; i < size; ++i) |
62 | if (0 != (*columns)[i]->compareAt(row_num, other.row_num, *(*other.columns)[i], 1)) |
63 | return false; |
64 | return true; |
65 | } |
66 | |
67 | bool operator!=(const SharedBlockRowRef & other) const |
68 | { |
69 | return !(*this == other); |
70 | } |
71 | |
72 | void reset() |
73 | { |
74 | SharedBlockRowRef empty; |
75 | swap(empty); |
76 | } |
77 | |
78 | bool empty() const { return columns == nullptr; } |
79 | size_t size() const { return empty() ? 0 : columns->size(); } |
80 | |
81 | void set(SharedBlockPtr & shared_block_, ColumnRawPtrs * columns_, size_t row_num_) |
82 | { |
83 | shared_block = shared_block_; |
84 | columns = columns_; |
85 | row_num = row_num_; |
86 | } |
87 | }; |
88 | |
89 | } |
90 | |