clickhouse_readonly/block/
row.rs

1use std::{marker, sync::Arc};
2
3use crate::{
4    column::{Column, ColumnType},
5    types::{FromSql, SqlType},
6};
7
8use crate::{
9    block::{Block, ColumnIdx},
10    error::Result,
11};
12
13/// A row from Clickhouse
14pub struct Row<'a, K: ColumnType> {
15    pub(crate) row: usize,
16    pub(crate) block_ref: BlockRef<'a, K>,
17    pub(crate) kind: marker::PhantomData<K>,
18}
19
20impl<'a, K: ColumnType> Row<'a, K> {
21    /// Get the value of a particular cell of the row.
22    pub fn get<T, I>(&'a self, col: I) -> Result<T>
23    where
24        T: FromSql<'a>,
25        I: ColumnIdx + Copy,
26    {
27        self.block_ref.get(self.row, col)
28    }
29
30    /// Return the number of cells in the current row.
31    pub fn len(&self) -> usize {
32        self.block_ref.column_count()
33    }
34
35    /// Returns `true` if the row contains no cells.
36    pub fn is_empty(&self) -> bool {
37        self.len() == 0
38    }
39
40    /// Get the name of a particular cell of the row.
41    pub fn name<I: ColumnIdx + Copy>(&self, col: I) -> Result<&str> {
42        Ok(self.block_ref.get_column(col)?.name())
43    }
44
45    /// Get the type of a particular cell of the row.
46    pub fn sql_type<I: ColumnIdx + Copy>(&self, col: I) -> Result<SqlType> {
47        Ok(self.block_ref.get_column(col)?.sql_type())
48    }
49}
50
51pub(crate) enum BlockRef<'a, K: ColumnType> {
52    Borrowed(&'a Block<K>),
53    Owned(Arc<Block<K>>),
54}
55
56impl<'a, K: ColumnType> Clone for BlockRef<'a, K> {
57    fn clone(&self) -> Self {
58        match self {
59            BlockRef::Borrowed(block_ref) => BlockRef::Borrowed(*block_ref),
60            BlockRef::Owned(block_ref) => BlockRef::Owned(block_ref.clone()),
61        }
62    }
63}
64
65impl<'a, K: ColumnType> BlockRef<'a, K> {
66    fn row_count(&self) -> usize {
67        match self {
68            BlockRef::Borrowed(block) => block.row_count(),
69            BlockRef::Owned(block) => block.row_count(),
70        }
71    }
72
73    fn column_count(&self) -> usize {
74        match self {
75            BlockRef::Borrowed(block) => block.column_count(),
76            BlockRef::Owned(block) => block.column_count(),
77        }
78    }
79
80    fn get<'s, T, I>(&'s self, row: usize, col: I) -> Result<T>
81    where
82        T: FromSql<'s>,
83        I: ColumnIdx + Copy,
84    {
85        match self {
86            BlockRef::Borrowed(block) => block.get(row, col),
87            BlockRef::Owned(block) => block.get(row, col),
88        }
89    }
90
91    fn get_column<I: ColumnIdx + Copy>(&self, col: I) -> Result<&Column<K>> {
92        match self {
93            BlockRef::Borrowed(block) => {
94                let column_index = col.get_index(block.columns())?;
95                Ok(&block.columns[column_index])
96            }
97            BlockRef::Owned(block) => {
98                let column_index = col.get_index(block.columns())?;
99                Ok(&block.columns[column_index])
100            }
101        }
102    }
103}
104
105/// Immutable rows iterator
106pub struct Rows<'a, K: ColumnType> {
107    pub(crate) row: usize,
108    pub(crate) block_ref: BlockRef<'a, K>,
109    pub(crate) kind: marker::PhantomData<K>,
110}
111
112impl<'a, K: ColumnType> Iterator for Rows<'a, K> {
113    type Item = Row<'a, K>;
114
115    fn next(&mut self) -> Option<Self::Item> {
116        if self.row >= self.block_ref.row_count() {
117            return None;
118        }
119        let result = Some(Row {
120            row: self.row,
121            block_ref: self.block_ref.clone(),
122            kind: marker::PhantomData,
123        });
124        self.row += 1;
125        result
126    }
127}
clickhouse_readonly/block/row.rs

clickhouse_readonly/block/
row.rs
