forked from couchbaselabs/tuqtng
-
Notifications
You must be signed in to change notification settings - Fork 0
/
grouper.go
130 lines (116 loc) · 3.77 KB
/
grouper.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
// Copyright (c) 2013 Couchbase, 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 xpipeline
import (
"github.com/couchbaselabs/clog"
"github.com/couchbaselabs/dparval"
"github.com/couchbaselabs/tuqtng/ast"
"github.com/couchbaselabs/tuqtng/misc"
"github.com/couchbaselabs/tuqtng/network"
"github.com/couchbaselabs/tuqtng/query"
)
type Grouper struct {
Base *BaseOperator
GroupBy ast.ExpressionList
groups map[string]*dparval.Value
Aggregates ast.ExpressionList
groupAll bool
}
func NewGrouper(groupBy ast.ExpressionList, aggs ast.ExpressionList) *Grouper {
rv := &Grouper{
Base: NewBaseOperator(),
GroupBy: groupBy,
groups: make(map[string]*dparval.Value),
Aggregates: aggs,
}
if len(groupBy) == 0 {
// group all behavior
rv.GroupBy = ast.ExpressionList{ast.NewLiteralBool(true)}
rv.groupAll = true
}
return rv
}
func (this *Grouper) SetSource(source Operator) {
this.Base.SetSource(source)
}
func (this *Grouper) GetChannels() (dparval.ValueChannel, PipelineSupportChannel) {
return this.Base.GetChannels()
}
func (this *Grouper) Run(stopChannel misc.StopChannel) {
clog.To(CHANNEL, "group operator starting")
this.Base.RunOperator(this, stopChannel)
clog.To(CHANNEL, "group operator finished")
}
func (this *Grouper) processItem(item *dparval.Value) bool {
groupkey := dparval.NewValue(make([]interface{}, len(this.GroupBy)))
for i, groupElement := range this.GroupBy {
groupkeyval, err := this.Base.Evaluate(groupElement, item)
if err == nil {
groupkey.SetIndex(i, groupkeyval)
} else {
switch err := err.(type) {
case *dparval.Undefined:
// FIXME better way?
groupkey.SetIndex(i, "__tuqtng__MISSING__")
default:
return this.Base.SendError(query.NewError(err, "error evaluating group by"))
}
}
}
// FIXME slow, but lets me use map to match same groups
groupkeybytes := groupkey.Bytes()
groupkeystring := string(groupkeybytes)
group, ok := this.groups[groupkeystring]
if !ok {
// new group
this.groups[groupkeystring] = item
group = item
this.setGroupDefaults(group)
}
this.updateGroup(group, item)
return true
}
func (this *Grouper) setGroupDefaults(group *dparval.Value) {
// here we should ask each aggregate function to initialize default values for the group
for _, agg := range this.Aggregates {
switch agg := agg.(type) {
case ast.AggregateFunctionCallExpression:
err := agg.DefaultAggregate(group)
if err != nil {
this.Base.SendError(query.NewError(err, "error setting group defaults"))
}
}
}
}
func (this *Grouper) updateGroup(group *dparval.Value, val *dparval.Value) {
// here we should update aggregate functions with this new item
for _, agg := range this.Aggregates {
switch agg := agg.(type) {
case ast.AggregateFunctionCallExpression:
err := agg.UpdateAggregate(group, val)
if err != nil {
this.Base.SendError(query.NewError(err, "error updating group info"))
}
}
}
}
func (this *Grouper) afterItems() {
for _, group := range this.groups {
this.Base.SendItem(group)
}
if this.groupAll && len(this.groups) == 0 {
// need to report correctly on the empty group
group := dparval.NewValue(map[string]interface{}{})
this.setGroupDefaults(group)
this.Base.SendItem(group)
}
}
func (this *Grouper) SetQuery(q network.Query) {
this.Base.SetQuery(q)
}