gf/internal/empty/empty.go
2021-10-06 19:52:19 +08:00

341 lines
6.9 KiB
Go

// Copyright GoFrame gf Author(https://goframe.org). All Rights Reserved.
//
// This Source Code Form is subject to the terms of the MIT License.
// If a copy of the MIT was not distributed with this file,
// You can obtain one at https://github.com/gogf/gf.
// Package empty provides functions for checking empty/nil variables.
package empty
import (
"reflect"
"time"
)
// iString is used for type assert api for String().
type iString interface {
String() string
}
// iInterfaces is used for type assert api for Interfaces.
type iInterfaces interface {
Interfaces() []interface{}
}
// iMapStrAny is the interface support for converting struct parameter to map.
type iMapStrAny interface {
MapStrAny() map[string]interface{}
}
type iTime interface {
Date() (year int, month time.Month, day int)
IsZero() bool
}
// IsEmpty checks whether given `value` empty.
// It returns true if `value` is in: 0, nil, false, "", len(slice/map/chan) == 0,
// or else it returns false.
func IsEmpty(value interface{}) bool {
if value == nil {
return true
}
// It firstly checks the variable as common types using assertion to enhance the performance,
// and then using reflection.
switch result := value.(type) {
case int:
return result == 0
case int8:
return result == 0
case int16:
return result == 0
case int32:
return result == 0
case int64:
return result == 0
case uint:
return result == 0
case uint8:
return result == 0
case uint16:
return result == 0
case uint32:
return result == 0
case uint64:
return result == 0
case float32:
return result == 0
case float64:
return result == 0
case bool:
return result == false
case string:
return result == ""
case []byte:
return len(result) == 0
case []rune:
return len(result) == 0
case []int:
return len(result) == 0
case []string:
return len(result) == 0
case []float32:
return len(result) == 0
case []float64:
return len(result) == 0
case map[string]interface{}:
return len(result) == 0
default:
// =========================
// Common interfaces checks.
// =========================
if f, ok := value.(iTime); ok {
if f == nil {
return true
}
return f.IsZero()
}
if f, ok := value.(iString); ok {
if f == nil {
return true
}
return f.String() == ""
}
if f, ok := value.(iInterfaces); ok {
if f == nil {
return true
}
return len(f.Interfaces()) == 0
}
if f, ok := value.(iMapStrAny); ok {
if f == nil {
return true
}
return len(f.MapStrAny()) == 0
}
// Finally, using reflect.
var rv reflect.Value
if v, ok := value.(reflect.Value); ok {
rv = v
} else {
rv = reflect.ValueOf(value)
}
switch rv.Kind() {
case reflect.Bool:
return !rv.Bool()
case
reflect.Int,
reflect.Int8,
reflect.Int16,
reflect.Int32,
reflect.Int64:
return rv.Int() == 0
case
reflect.Uint,
reflect.Uint8,
reflect.Uint16,
reflect.Uint32,
reflect.Uint64,
reflect.Uintptr:
return rv.Uint() == 0
case
reflect.Float32,
reflect.Float64:
return rv.Float() == 0
case reflect.String:
return rv.Len() == 0
case reflect.Struct:
for i := 0; i < rv.NumField(); i++ {
if !IsEmpty(rv.Field(i).Interface()) {
return false
}
}
return true
case
reflect.Chan,
reflect.Map,
reflect.Slice,
reflect.Array:
return rv.Len() == 0
case
reflect.Func,
reflect.Ptr,
reflect.Interface,
reflect.UnsafePointer:
if rv.IsNil() {
return true
}
}
}
return false
}
// IsEmptyLength checks whether given `value` is empty length.
// It returns true if `value` is in: nil, "", len(slice/map/chan) == 0,
// or else it returns false.
//func IsEmptyLength(value interface{}) bool {
// if value == nil {
// return true
// }
// // It firstly checks the variable as common types using assertion to enhance the performance,
// // and then using reflection.
// switch value := value.(type) {
// case
// int,
// int8,
// int16,
// int32,
// int64,
// uint,
// uint8,
// uint16,
// uint32,
// uint64,
// float32,
// float64,
// bool:
// return false
// case string:
// return value == ""
// case []byte:
// return len(value) == 0
// case []rune:
// return len(value) == 0
// case []int:
// return len(value) == 0
// case []string:
// return len(value) == 0
// case []float32:
// return len(value) == 0
// case []float64:
// return len(value) == 0
// case map[string]interface{}:
// return len(value) == 0
// default:
// // =========================
// // Common interfaces checks.
// // =========================
// if f, ok := value.(iTime); ok {
// if f == nil {
// return true
// }
// return f.IsZero()
// }
// if f, ok := value.(iString); ok {
// if f == nil {
// return true
// }
// return f.String() == ""
// }
// if f, ok := value.(iInterfaces); ok {
// if f == nil {
// return true
// }
// return len(f.Interfaces()) == 0
// }
// if f, ok := value.(iMapStrAny); ok {
// if f == nil {
// return true
// }
// return len(f.MapStrAny()) == 0
// }
// // Finally using reflect.
// var rv reflect.Value
// if v, ok := value.(reflect.Value); ok {
// rv = v
// } else {
// rv = reflect.ValueOf(value)
// }
//
// switch rv.Kind() {
// case
// reflect.Int,
// reflect.Int8,
// reflect.Int16,
// reflect.Int32,
// reflect.Int64,
// reflect.Uint,
// reflect.Uint8,
// reflect.Uint16,
// reflect.Uint32,
// reflect.Uint64,
// reflect.Uintptr,
// reflect.Float32,
// reflect.Float64,
// reflect.Bool:
// return false
// case reflect.String:
// return rv.Len() == 0
// case reflect.Struct:
// for i := 0; i < rv.NumField(); i++ {
// if !IsEmpty(rv) {
// return false
// }
// }
// return true
// case reflect.Chan,
// reflect.Map,
// reflect.Slice,
// reflect.Array:
// return rv.Len() == 0
// case reflect.Func,
// reflect.Ptr,
// reflect.Interface,
// reflect.UnsafePointer:
// if rv.IsNil() {
// return true
// }
// }
// }
// return false
//}
// IsNil checks whether given `value` is nil.
// Parameter `traceSource` is used for tracing to the source variable if given `value` is type of pinter
// that also points to a pointer. It returns nil if the source is nil when `traceSource` is true.
// Note that it might use reflect feature which affects performance a little.
func IsNil(value interface{}, traceSource ...bool) bool {
if value == nil {
return true
}
var rv reflect.Value
if v, ok := value.(reflect.Value); ok {
rv = v
} else {
rv = reflect.ValueOf(value)
}
switch rv.Kind() {
case reflect.Chan,
reflect.Map,
reflect.Slice,
reflect.Func,
reflect.Interface,
reflect.UnsafePointer:
return !rv.IsValid() || rv.IsNil()
case reflect.Ptr:
if len(traceSource) > 0 && traceSource[0] {
for rv.Kind() == reflect.Ptr {
rv = rv.Elem()
}
if !rv.IsValid() {
return true
}
if rv.Kind() == reflect.Ptr {
return rv.IsNil()
}
} else {
return !rv.IsValid() || rv.IsNil()
}
}
return false
}