-
Notifications
You must be signed in to change notification settings - Fork 378
/
count.go
89 lines (77 loc) · 2.5 KB
/
count.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
// Copyright 2021 FerretDB 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 stages
import (
"context"
"strings"
"github.com/FerretDB/FerretDB/internal/handlers/common"
"github.com/FerretDB/FerretDB/internal/handlers/common/aggregations"
"github.com/FerretDB/FerretDB/internal/handlers/commonerrors"
"github.com/FerretDB/FerretDB/internal/types"
"github.com/FerretDB/FerretDB/internal/util/iterator"
)
// count represents $count stage.
type count struct {
field string
}
// newCount creates a new $count stage.
func newCount(stage *types.Document) (aggregations.Stage, error) {
field, err := common.GetRequiredParam[string](stage, "$count")
if err != nil {
return nil, commonerrors.NewCommandErrorMsgWithArgument(
commonerrors.ErrStageCountNonString,
"the count field must be a non-empty string",
"$count (stage)",
)
}
if len(field) == 0 {
return nil, commonerrors.NewCommandErrorMsgWithArgument(
commonerrors.ErrStageCountNonEmptyString,
"the count field must be a non-empty string",
"$count (stage)",
)
}
if strings.Contains(field, ".") {
return nil, commonerrors.NewCommandErrorMsgWithArgument(
commonerrors.ErrStageCountBadValue,
"the count field cannot contain '.'",
"$count (stage)",
)
}
if strings.HasPrefix(field, "$") {
return nil, commonerrors.NewCommandErrorMsgWithArgument(
commonerrors.ErrStageCountBadPrefix,
"the count field cannot be a $-prefixed path",
"$count (stage)",
)
}
if field == "_id" {
return nil, commonerrors.NewCommandErrorMsgWithArgument(
commonerrors.ErrStageGroupID,
"a group's _id may only be specified once",
"$count (stage)",
)
}
return &count{
field: field,
}, nil
}
// Process implements Stage interface.
func (c *count) Process(ctx context.Context, iter types.DocumentsIterator, closer *iterator.MultiCloser) (types.DocumentsIterator, error) { //nolint:lll // for readability
return common.CountIterator(iter, closer, c.field), nil
}
// check interfaces
var (
_ aggregations.Stage = (*count)(nil)
)