forked from dolthub/go-mysql-server
/
table_iter.go
142 lines (118 loc) · 2.88 KB
/
table_iter.go
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
// Copyright 2020-2021 Dolthub, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package sql
import (
"fmt"
"io"
)
// TableRowIter is an iterator over the partitions in a table.
type TableRowIter struct {
table Table
partitions PartitionIter
partition Partition
rows RowIter
rows2 RowIter2
}
var _ RowIter = (*TableRowIter)(nil)
var _ RowIter2 = (*TableRowIter)(nil)
// NewTableRowIter returns a new iterator over the rows in the partitions of the table given.
func NewTableRowIter(ctx *Context, table Table, partitions PartitionIter) *TableRowIter {
return &TableRowIter{table: table, partitions: partitions}
}
func (i *TableRowIter) Next(ctx *Context) (Row, error) {
if ctx.Err() != nil {
return nil, ctx.Err()
}
if i.partition == nil {
partition, err := i.partitions.Next(ctx)
if err != nil {
if err == io.EOF {
if e := i.partitions.Close(ctx); e != nil {
return nil, e
}
}
return nil, err
}
i.partition = partition
}
if i.rows == nil {
rows, err := i.table.PartitionRows(ctx, i.partition)
if err != nil {
return nil, err
}
i.rows = rows
}
row, err := i.rows.Next(ctx)
if err != nil && err == io.EOF {
if err = i.rows.Close(ctx); err != nil {
return nil, err
}
i.partition = nil
i.rows = nil
row, err = i.Next(ctx)
}
select {
case <-ctx.Done():
return nil, ctx.Err()
default:
}
return row, err
}
func (i *TableRowIter) Next2(ctx *Context, frame *RowFrame) error {
if ctx.Err() != nil {
return ctx.Err()
}
if i.partition == nil {
partition, err := i.partitions.Next(ctx)
if err != nil {
if err == io.EOF {
if e := i.partitions.Close(ctx); e != nil {
return e
}
}
return err
}
i.partition = partition
}
if i.rows2 == nil {
t2, ok := i.table.(Table2)
if !ok {
return fmt.Errorf("table does not implement Table2: %s (%T)", i.table.Name(), i.table)
}
rows, err := t2.PartitionRows2(ctx, i.partition)
if err != nil {
return err
}
i.rows2 = rows
}
err := i.rows2.Next2(ctx, frame)
if err != nil && err == io.EOF {
if err = i.rows2.Close(ctx); err != nil {
return err
}
i.partition = nil
i.rows2 = nil
return i.Next2(ctx, frame)
}
return err
}
func (i *TableRowIter) Close(ctx *Context) error {
if i.rows != nil {
if err := i.rows.Close(ctx); err != nil {
_ = i.partitions.Close(ctx)
return err
}
}
return i.partitions.Close(ctx)
}