summaryrefslogtreecommitdiff
path: root/vendor/github.com/gorilla/schema/encoder.go
blob: bf1d511e6f8dd2866302bc8229c12a87f9720dfb (plain)
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
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
package schema

import (
	"errors"
	"fmt"
	"reflect"
	"strconv"
)

type encoderFunc func(reflect.Value) string

// Encoder encodes values from a struct into url.Values.
type Encoder struct {
	cache  *cache
	regenc map[reflect.Type]encoderFunc
}

// NewEncoder returns a new Encoder with defaults.
func NewEncoder() *Encoder {
	return &Encoder{cache: newCache(), regenc: make(map[reflect.Type]encoderFunc)}
}

// Encode encodes a struct into map[string][]string.
//
// Intended for use with url.Values.
func (e *Encoder) Encode(src interface{}, dst map[string][]string) error {
	v := reflect.ValueOf(src)

	return e.encode(v, dst)
}

// RegisterEncoder registers a converter for encoding a custom type.
func (e *Encoder) RegisterEncoder(value interface{}, encoder func(reflect.Value) string) {
	e.regenc[reflect.TypeOf(value)] = encoder
}

// SetAliasTag changes the tag used to locate custom field aliases.
// The default tag is "schema".
func (e *Encoder) SetAliasTag(tag string) {
	e.cache.tag = tag
}

// isValidStructPointer test if input value is a valid struct pointer.
func isValidStructPointer(v reflect.Value) bool {
	return v.Type().Kind() == reflect.Ptr && v.Elem().IsValid() && v.Elem().Type().Kind() == reflect.Struct
}

func isZero(v reflect.Value) bool {
	switch v.Kind() {
	case reflect.Func:
	case reflect.Map, reflect.Slice:
		return v.IsNil() || v.Len() == 0
	case reflect.Array:
		z := true
		for i := 0; i < v.Len(); i++ {
			z = z && isZero(v.Index(i))
		}
		return z
	case reflect.Struct:
		z := true
		for i := 0; i < v.NumField(); i++ {
			z = z && isZero(v.Field(i))
		}
		return z
	}
	// Compare other types directly:
	z := reflect.Zero(v.Type())
	return v.Interface() == z.Interface()
}

func (e *Encoder) encode(v reflect.Value, dst map[string][]string) error {
	if v.Kind() == reflect.Ptr {
		v = v.Elem()
	}
	if v.Kind() != reflect.Struct {
		return errors.New("schema: interface must be a struct")
	}
	t := v.Type()

	errors := MultiError{}

	for i := 0; i < v.NumField(); i++ {
		name, opts := fieldAlias(t.Field(i), e.cache.tag)
		if name == "-" {
			continue
		}

		// Encode struct pointer types if the field is a valid pointer and a struct.
		if isValidStructPointer(v.Field(i)) {
			e.encode(v.Field(i).Elem(), dst)
			continue
		}

		encFunc := typeEncoder(v.Field(i).Type(), e.regenc)

		// Encode non-slice types and custom implementations immediately.
		if encFunc != nil {
			value := encFunc(v.Field(i))
			if opts.Contains("omitempty") && isZero(v.Field(i)) {
				continue
			}

			dst[name] = append(dst[name], value)
			continue
		}

		if v.Field(i).Type().Kind() == reflect.Struct {
			e.encode(v.Field(i), dst)
			continue
		}

		if v.Field(i).Type().Kind() == reflect.Slice {
			encFunc = typeEncoder(v.Field(i).Type().Elem(), e.regenc)
		}

		if encFunc == nil {
			errors[v.Field(i).Type().String()] = fmt.Errorf("schema: encoder not found for %v", v.Field(i))
			continue
		}

		// Encode a slice.
		if v.Field(i).Len() == 0 && opts.Contains("omitempty") {
			continue
		}

		dst[name] = []string{}
		for j := 0; j < v.Field(i).Len(); j++ {
			dst[name] = append(dst[name], encFunc(v.Field(i).Index(j)))
		}
	}

	if len(errors) > 0 {
		return errors
	}
	return nil
}

func typeEncoder(t reflect.Type, reg map[reflect.Type]encoderFunc) encoderFunc {
	if f, ok := reg[t]; ok {
		return f
	}

	switch t.Kind() {
	case reflect.Bool:
		return encodeBool
	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
		return encodeInt
	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
		return encodeUint
	case reflect.Float32:
		return encodeFloat32
	case reflect.Float64:
		return encodeFloat64
	case reflect.Ptr:
		f := typeEncoder(t.Elem(), reg)
		return func(v reflect.Value) string {
			if v.IsNil() {
				return "null"
			}
			return f(v.Elem())
		}
	case reflect.String:
		return encodeString
	default:
		return nil
	}
}

func encodeBool(v reflect.Value) string {
	return strconv.FormatBool(v.Bool())
}

func encodeInt(v reflect.Value) string {
	return strconv.FormatInt(int64(v.Int()), 10)
}

func encodeUint(v reflect.Value) string {
	return strconv.FormatUint(uint64(v.Uint()), 10)
}

func encodeFloat(v reflect.Value, bits int) string {
	return strconv.FormatFloat(v.Float(), 'f', 6, bits)
}

func encodeFloat32(v reflect.Value) string {
	return encodeFloat(v, 32)
}

func encodeFloat64(v reflect.Value) string {
	return encodeFloat(v, 64)
}

func encodeString(v reflect.Value) string {
	return v.String()
}