💯Go Struct and Field validation, including Cross Field, Cross Struct, Map, Slice and Array diving
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validator/cache.go

285 lines
6.0 KiB

package validator
import (
"fmt"
"reflect"
"strings"
"sync"
"sync/atomic"
)
type tagType uint8
const (
typeDefault tagType = iota
typeOmitEmpty
typeNoStructLevel
typeStructOnly
typeDive
typeOr
typeExists
)
const (
invalidValidation = "Invalid validation tag on field %s"
undefinedValidation = "Undefined validation function on field %s"
)
// var (
// validatable = reflect.TypeOf((*Validatable)(nil)).Elem()
// )
type structCache struct {
lock sync.Mutex
m atomic.Value // map[reflect.Type]*cStruct
}
func (sc *structCache) Get(key reflect.Type) (c *cStruct, found bool) {
c, found = sc.m.Load().(map[reflect.Type]*cStruct)[key]
return
}
func (sc *structCache) Set(key reflect.Type, value *cStruct) {
m := sc.m.Load().(map[reflect.Type]*cStruct)
nm := make(map[reflect.Type]*cStruct, len(m)+1)
for k, v := range m {
nm[k] = v
}
nm[key] = value
sc.m.Store(nm)
}
type tagCache struct {
lock sync.Mutex
m atomic.Value // map[string]*cTag
}
func (tc *tagCache) Get(key string) (c *cTag, found bool) {
c, found = tc.m.Load().(map[string]*cTag)[key]
return
}
func (tc *tagCache) Set(key string, value *cTag) {
m := tc.m.Load().(map[string]*cTag)
nm := make(map[string]*cTag, len(m)+1)
for k, v := range m {
nm[k] = v
}
nm[key] = value
tc.m.Store(nm)
}
type cStruct struct {
Name string
fields map[int]*cField
fn StructLevelFunc
}
type cField struct {
Idx int
Name string
AltName string
cTags *cTag
}
type cTag struct {
tag string
aliasTag string
actualAliasTag string
param string
hasAlias bool
typeof tagType
hasTag bool
fn Func
next *cTag
}
func (v *Validate) extractStructCache(current reflect.Value, sName string) *cStruct {
v.structCache.lock.Lock()
defer v.structCache.lock.Unlock() // leave as defer! because if inner panics, it will never get unlocked otherwise!
typ := current.Type()
// could have been multiple trying to access, but once first is done this ensures struct
// isn't parsed again.
cs, ok := v.structCache.Get(typ)
if ok {
return cs
}
cs = &cStruct{Name: sName, fields: make(map[int]*cField), fn: v.structLevelFuncs[typ]}
// newVal := reflect.New(typ)
// // fmt.Println("implements:", reflect.PtrTo(typ).Implements(validatable))
// tv1, tv2 := newVal.Interface().(Validatable)
// // tv1, tv2 := reflect.PtrTo(typ).Elem().(Validatable)
// fmt.Println("implements2:", tv1, tv2)
// // fmt.Println("Testing if Validatable", tv1, tv2, reflect.PtrTo(typ), current, current.Type(), typ)
// if vable, ok := reflect.New(typ).Interface().(Validatable); ok {
// // fmt.Println("Validatable", cs.fn)
// if cs.fn != nil {
// log.Println("warning: struct level validation overriding 'Validatabe' interface function")
// } else {
// cs.fn = vable.Validate
// // fmt.Println(cs.fn)
// }
// }
numFields := current.NumField()
var ctag *cTag
var fld reflect.StructField
var tag string
var customName string
for i := 0; i < numFields; i++ {
fld = typ.Field(i)
if !fld.Anonymous && len(fld.PkgPath) > 0 {
continue
}
tag = fld.Tag.Get(v.tagName)
if tag == skipValidationTag {
continue
}
customName = fld.Name
if v.hasTagNameFunc {
name := v.tagNameFunc(fld)
if len(name) > 0 {
customName = name
}
}
// NOTE: cannot use shared tag cache, because tags may be equal, but things like alias may be different
// and so only struct level caching can be used instead of combined with Field tag caching
if len(tag) > 0 {
ctag, _ = v.parseFieldTagsRecursive(tag, fld.Name, "", false)
} else {
// even if field doesn't have validations need cTag for traversing to potential inner/nested
// elements of the field.
ctag = new(cTag)
}
cs.fields[i] = &cField{Idx: i, Name: fld.Name, AltName: customName, cTags: ctag}
}
v.structCache.Set(typ, cs)
return cs
}
func (v *Validate) parseFieldTagsRecursive(tag string, fieldName string, alias string, hasAlias bool) (firstCtag *cTag, current *cTag) {
var t string
var ok bool
noAlias := len(alias) == 0
tags := strings.Split(tag, tagSeparator)
for i := 0; i < len(tags); i++ {
t = tags[i]
if noAlias {
alias = t
}
// check map for alias and process new tags, otherwise process as usual
if tagsVal, found := v.aliases[t]; found {
if i == 0 {
firstCtag, current = v.parseFieldTagsRecursive(tagsVal, fieldName, t, true)
} else {
next, curr := v.parseFieldTagsRecursive(tagsVal, fieldName, t, true)
current.next, current = next, curr
}
continue
}
if i == 0 {
current = &cTag{aliasTag: alias, hasAlias: hasAlias, hasTag: true}
firstCtag = current
} else {
current.next = &cTag{aliasTag: alias, hasAlias: hasAlias, hasTag: true}
current = current.next
}
switch t {
case diveTag:
current.typeof = typeDive
continue
case omitempty:
current.typeof = typeOmitEmpty
continue
case structOnlyTag:
current.typeof = typeStructOnly
continue
case noStructLevelTag:
current.typeof = typeNoStructLevel
continue
default:
// if a pipe character is needed within the param you must use the utf8Pipe representation "0x7C"
orVals := strings.Split(t, orSeparator)
for j := 0; j < len(orVals); j++ {
vals := strings.SplitN(orVals[j], tagKeySeparator, 2)
if noAlias {
alias = vals[0]
current.aliasTag = alias
} else {
current.actualAliasTag = t
}
if j > 0 {
current.next = &cTag{aliasTag: alias, actualAliasTag: current.actualAliasTag, hasAlias: hasAlias, hasTag: true}
current = current.next
}
current.tag = vals[0]
if len(current.tag) == 0 {
panic(strings.TrimSpace(fmt.Sprintf(invalidValidation, fieldName)))
}
if current.fn, ok = v.validations[current.tag]; !ok {
panic(strings.TrimSpace(fmt.Sprintf(undefinedValidation, fieldName)))
}
if len(orVals) > 1 {
current.typeof = typeOr
}
if len(vals) > 1 {
current.param = strings.Replace(strings.Replace(vals[1], utf8HexComma, ",", -1), utf8Pipe, "|", -1)
}
}
}
}
return
}