/
output.go
98 lines (85 loc) · 2.98 KB
/
output.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
// Licensed to the Apache Software Foundation (ASF) under one or more
// contributor license agreements. See the NOTICE file distributed with
// this work for additional information regarding copyright ownership.
// The ASF licenses this file to You 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 funcx
import (
"reflect"
"github.com/apache/beam/sdks/v2/go/pkg/beam/core/typex"
"github.com/apache/beam/sdks/v2/go/pkg/beam/internal/errors"
)
var (
errIllegalParametersInEmit = "All parameters in an emit must be universal type, container type, or concrete type"
)
// IsEmit returns true iff the supplied type is an emitter.
func IsEmit(t reflect.Type) bool {
_, ok, _ := unfoldEmit(t)
return ok
}
// IsMalformedEmit returns true iff the supplied type is an illegal emitter
// and an error explaining why it is illegal. For example, an emitter is illegal
// if one of its parameters is not concrete. If the type does not have the structure
// of an emitter or it is a legal emitter, IsMalformedEmit returns false and no error.
func IsMalformedEmit(t reflect.Type) (bool, error) {
_, _, err := unfoldEmit(t)
return err != nil, err
}
// IsEmitWithEventTime return true iff the supplied type is an
// emitter and the first argument is the optional EventTime.
func IsEmitWithEventTime(t reflect.Type) bool {
types, ok, _ := unfoldEmit(t)
return ok && types[0] == typex.EventTimeType
}
// UnfoldEmit returns the parameter types, if an emitter. For example:
//
// func (int) returns {int}
// func (string, int) returns {string, int}
// func (typex.EventTime, int) returns {typex.EventTime, int}
//
func UnfoldEmit(t reflect.Type) ([]reflect.Type, bool) {
types, ok, _ := unfoldEmit(t)
return types, ok
}
func unfoldEmit(t reflect.Type) ([]reflect.Type, bool, error) {
if t.Kind() != reflect.Func {
return nil, false, nil
}
if t.NumOut() != 0 {
return nil, false, nil
}
if t.NumIn() == 0 {
return nil, false, nil
}
var ret []reflect.Type
skip := 0
if t.In(0) == typex.EventTimeType {
ret = append(ret, typex.EventTimeType)
skip = 1
}
if t.NumIn()-skip > 2 || t.NumIn() == skip {
return nil, false, nil
}
for i := skip; i < t.NumIn(); i++ {
if ok, err := isInParam(t.In(i)); !ok {
return nil, false, errors.Wrap(err, errIllegalParametersInEmit)
}
ret = append(ret, t.In(i))
}
return ret, true, nil
}
func isInParam(t reflect.Type) (bool, error) {
if typex.IsUniversal(t) || typex.IsContainer(t) {
return true, nil
}
return typex.CheckConcrete(t)
}