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package gocsv
import (
"fmt"
"reflect"
"strconv"
"strings"
"sync"
)
// --------------------------------------------------------------------------
// Reflection helpers
type structInfo struct {
Fields []fieldInfo
}
// fieldInfo is a struct field that should be mapped to a CSV column, or vice-versa
// Each IndexChain element before the last is the index of an the embedded struct field
// that defines Key as a tag
type fieldInfo struct {
keys []string
omitEmpty bool
IndexChain []int
defaultValue string
}
func (f fieldInfo) getFirstKey() string {
return f.keys[0]
}
func (f fieldInfo) matchesKey(key string) bool {
for _, k := range f.keys {
if key == k || strings.TrimSpace(key) == k {
return true
}
}
return false
}
var structInfoCache sync.Map
var structMap = make(map[reflect.Type]*structInfo)
var structMapMutex sync.RWMutex
func getStructInfo(rType reflect.Type) *structInfo {
stInfo, ok := structInfoCache.Load(rType)
if ok {
return stInfo.(*structInfo)
}
fieldsList := getFieldInfos(rType, []int{})
stInfo = &structInfo{fieldsList}
structInfoCache.Store(rType, stInfo)
return stInfo.(*structInfo)
}
func getFieldInfos(rType reflect.Type, parentIndexChain []int) []fieldInfo {
fieldsCount := rType.NumField()
fieldsList := make([]fieldInfo, 0, fieldsCount)
for i := 0; i < fieldsCount; i++ {
field := rType.Field(i)
if field.PkgPath != "" {
continue
}
var cpy = make([]int, len(parentIndexChain))
copy(cpy, parentIndexChain)
indexChain := append(cpy, i)
// if the field is a pointer to a struct, follow the pointer then create fieldinfo for each field
if field.Type.Kind() == reflect.Ptr && field.Type.Elem().Kind() == reflect.Struct {
// Structs that implement any of the text or CSV marshaling methods
// should result in one value and not have their fields exposed
if !(canMarshal(field.Type.Elem()) || canMarshal(field.Type)) {
fieldsList = append(fieldsList, getFieldInfos(field.Type.Elem(), indexChain)...)
}
}
// if the field is a struct, create a fieldInfo for each of its fields
if field.Type.Kind() == reflect.Struct {
// Structs that implement any of the text or CSV marshaling methods
// should result in one value and not have their fields exposed
if !(canMarshal(field.Type)) {
fieldsList = append(fieldsList, getFieldInfos(field.Type, indexChain)...)
}
}
// if the field is an embedded struct, ignore the csv tag
if field.Anonymous {
continue
}
currFieldInfo := fieldInfo{IndexChain: indexChain}
fieldTag := field.Tag.Get(TagName)
fieldTags := strings.Split(fieldTag, TagSeparator)
filteredTags := []string{}
for _, fieldTagEntry := range fieldTags {
trimmedFieldTagEntry := strings.TrimSpace(fieldTagEntry) // handles cases like `csv:"foo, omitempty, default=test"`
if trimmedFieldTagEntry == "omitempty" {
currFieldInfo.omitEmpty = true
} else if strings.HasPrefix(trimmedFieldTagEntry, "default=") {
currFieldInfo.defaultValue = strings.TrimPrefix(trimmedFieldTagEntry, "default=")
} else {
filteredTags = append(filteredTags, normalizeName(trimmedFieldTagEntry))
}
}
if len(filteredTags) == 1 && filteredTags[0] == "-" {
continue
} else if len(filteredTags) > 0 && filteredTags[0] != "" {
currFieldInfo.keys = filteredTags
} else {
currFieldInfo.keys = []string{normalizeName(field.Name)}
}
if field.Type.Kind() == reflect.Slice || field.Type.Kind() == reflect.Array {
var arrayLength = -1
if arrayTag, ok := field.Tag.Lookup(TagName + "[]"); ok {
arrayLength, _ = strconv.Atoi(arrayTag)
}
// When the field is a slice/array of structs, create a fieldInfo for each index and each field
if field.Type.Elem().Kind() == reflect.Struct {
fieldInfos := getFieldInfos(field.Type.Elem(), []int{})
for idx := 0; idx < arrayLength; idx++ {
// copy index chain and append array index
var cpy2 = make([]int, len(indexChain))
copy(cpy2, indexChain)
arrayIndexChain := append(cpy2, idx)
for _, childFieldInfo := range fieldInfos {
// copy array index chain and append array index
var cpy3 = make([]int, len(arrayIndexChain))
copy(cpy3, arrayIndexChain)
arrayFieldInfo := fieldInfo{
IndexChain: append(cpy3, childFieldInfo.IndexChain...),
omitEmpty: childFieldInfo.omitEmpty,
defaultValue: childFieldInfo.defaultValue,
}
// create cartesian product of keys
// eg: array field keys x struct field keys
for _, akey := range currFieldInfo.keys {
for _, fkey := range childFieldInfo.keys {
arrayFieldInfo.keys = append(arrayFieldInfo.keys, normalizeName(fmt.Sprintf("%s[%d].%s", akey, idx, fkey)))
}
}
fieldsList = append(fieldsList, arrayFieldInfo)
}
}
} else if arrayLength > 0 {
// When the field is a slice/array of primitives, create a fieldInfo for each index
for idx := 0; idx < arrayLength; idx++ {
// copy index chain and append array index
var cpy2 = make([]int, len(indexChain))
copy(cpy2, indexChain)
arrayFieldInfo := fieldInfo{
IndexChain: append(cpy2, idx),
omitEmpty: currFieldInfo.omitEmpty,
defaultValue: currFieldInfo.defaultValue,
}
for _, akey := range currFieldInfo.keys {
arrayFieldInfo.keys = append(arrayFieldInfo.keys, normalizeName(fmt.Sprintf("%s[%d]", akey, idx)))
}
fieldsList = append(fieldsList, arrayFieldInfo)
}
} else {
fieldsList = append(fieldsList, currFieldInfo)
}
} else {
fieldsList = append(fieldsList, currFieldInfo)
}
}
return fieldsList
}
func getConcreteContainerInnerType(in reflect.Type) (inInnerWasPointer bool, inInnerType reflect.Type) {
inInnerType = in.Elem()
inInnerWasPointer = false
if inInnerType.Kind() == reflect.Ptr {
inInnerWasPointer = true
inInnerType = inInnerType.Elem()
}
return inInnerWasPointer, inInnerType
}
func getConcreteReflectValueAndType(in interface{}) (reflect.Value, reflect.Type) {
value := reflect.ValueOf(in)
if value.Kind() == reflect.Ptr {
value = value.Elem()
}
return value, value.Type()
}
var errorInterface = reflect.TypeOf((*error)(nil)).Elem()
func isErrorType(outType reflect.Type) bool {
if outType.Kind() != reflect.Interface {
return false
}
return outType.Implements(errorInterface)
}
|
