-
Notifications
You must be signed in to change notification settings - Fork 0
/
generator.go
142 lines (119 loc) · 3.72 KB
/
generator.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 2016 The Cockroach Authors.
//
// 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.
//
// Author: Raphael 'kena' Poss (knz@cockroachlabs.com)
package sql
import (
"fmt"
"github.com/pkg/errors"
"golang.org/x/net/context"
"github.com/cockroachdb/cockroach/pkg/roachpb"
"github.com/cockroachdb/cockroach/pkg/sql/parser"
"github.com/cockroachdb/cockroach/pkg/sql/sqlbase"
)
// valueGenerator represents a node that produces rows
// computationally, by means of a "generator function" (called
// "set-generating function" in PostgreSQL).
type valueGenerator struct {
p *planner
// expr holds the function call that needs to be performed,
// including its arguments that need evaluation, to obtain the
// generator object.
expr parser.TypedExpr
// gen is a reference to the generator object that produces the row
// for this planNode.
gen parser.ValueGenerator
// columns is the signature of this generator.
columns sqlbase.ResultColumns
// rowCount is used for DebugValues() only.
rowCount int
}
// makeGenerator creates a valueGenerator instance that wraps a call to a
// generator function.
func (p *planner) makeGenerator(ctx context.Context, t *parser.FuncExpr) (planNode, error) {
origName := t.Func.String()
if err := p.parser.AssertNoAggregationOrWindowing(t, "FROM", p.session.SearchPath); err != nil {
return nil, err
}
normalized, err := p.analyzeExpr(
ctx, t, multiSourceInfo{}, parser.IndexedVarHelper{}, parser.TypeAny, false, "FROM",
)
if err != nil {
return nil, err
}
tType, ok := normalized.ResolvedType().(parser.TTable)
if !ok {
return nil, errors.Errorf("FROM expression is not a generator: %s", t)
}
var columns sqlbase.ResultColumns
if len(tType.Cols) == 1 {
columns = sqlbase.ResultColumns{sqlbase.ResultColumn{Name: origName, Typ: tType.Cols[0]}}
} else {
columns = make(sqlbase.ResultColumns, len(tType.Cols))
for i, t := range tType.Cols {
columns[i] = sqlbase.ResultColumn{
Name: fmt.Sprintf("column%d", i+1),
Typ: t,
}
}
}
return &valueGenerator{
p: p,
expr: normalized,
columns: columns,
}, nil
}
func (n *valueGenerator) Start(context.Context) error {
expr, err := n.expr.Eval(&n.p.evalCtx)
if err != nil {
return err
}
var tb *parser.DTable
if expr == parser.DNull {
tb = parser.EmptyDTable()
} else {
tb = expr.(*parser.DTable)
}
gen := tb.ValueGenerator
if err := gen.Start(); err != nil {
return err
}
n.gen = gen
return nil
}
func (n *valueGenerator) Next(context.Context) (bool, error) {
n.rowCount++
return n.gen.Next()
}
func (n *valueGenerator) Close(context.Context) {
if n.gen != nil {
n.gen.Close()
}
}
func (n *valueGenerator) DebugValues() debugValues {
row := n.gen.Values()
return debugValues{
rowIdx: n.rowCount,
key: fmt.Sprintf("%d", n.rowCount),
value: row.String(),
output: debugValueRow,
}
}
func (n *valueGenerator) Spans(context.Context) (_, _ roachpb.Spans, _ error) {
return nil, nil, nil
}
func (n *valueGenerator) Ordering() orderingInfo { return orderingInfo{} }
func (n *valueGenerator) Values() parser.Datums { return n.gen.Values() }
func (n *valueGenerator) MarkDebug(_ explainMode) {}
func (n *valueGenerator) Columns() sqlbase.ResultColumns { return n.columns }