ref: 8f5c9a747fcebb02bb99f5de272046411eb15370
dir: /tpl/compare/compare.go/
// Copyright 2017 The Hugo Authors. All rights reserved.
//
// Licensed 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 compare provides template functions for comparing values.
package compare
import (
"fmt"
"reflect"
"strconv"
"time"
"github.com/gohugoio/hugo/compare"
"github.com/gohugoio/hugo/common/types"
)
// New returns a new instance of the compare-namespaced template functions.
func New(caseInsensitive bool) *Namespace {
return &Namespace{caseInsensitive: caseInsensitive}
}
// Namespace provides template functions for the "compare" namespace.
type Namespace struct {
// Enable to do case insensitive string compares.
caseInsensitive bool
}
// Default checks whether a given value is set and returns a default value if it
// is not. "Set" in this context means non-zero for numeric types and times;
// non-zero length for strings, arrays, slices, and maps;
// any boolean or struct value; or non-nil for any other types.
func (*Namespace) Default(dflt interface{}, given ...interface{}) (interface{}, error) {
// given is variadic because the following construct will not pass a piped
// argument when the key is missing: {{ index . "key" | default "foo" }}
// The Go template will complain that we got 1 argument when we expectd 2.
if len(given) == 0 {
return dflt, nil
}
if len(given) != 1 {
return nil, fmt.Errorf("wrong number of args for default: want 2 got %d", len(given)+1)
}
g := reflect.ValueOf(given[0])
if !g.IsValid() {
return dflt, nil
}
set := false
switch g.Kind() {
case reflect.Bool:
set = true
case reflect.String, reflect.Array, reflect.Slice, reflect.Map:
set = g.Len() != 0
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
set = g.Int() != 0
case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
set = g.Uint() != 0
case reflect.Float32, reflect.Float64:
set = g.Float() != 0
case reflect.Complex64, reflect.Complex128:
set = g.Complex() != 0
case reflect.Struct:
switch actual := given[0].(type) {
case time.Time:
set = !actual.IsZero()
default:
set = true
}
default:
set = !g.IsNil()
}
if set {
return given[0], nil
}
return dflt, nil
}
// Eq returns the boolean truth of arg1 == arg2 || arg1 == arg3 || arg1 == arg4.
func (n *Namespace) Eq(first interface{}, others ...interface{}) bool {
if n.caseInsensitive {
panic("caseInsensitive not implemented for Eq")
}
if len(others) == 0 {
panic("missing arguments for comparison")
}
normalize := func(v interface{}) interface{} {
if types.IsNil(v) {
return nil
}
vv := reflect.ValueOf(v)
switch vv.Kind() {
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
return vv.Int()
case reflect.Float32, reflect.Float64:
return vv.Float()
case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
return vv.Uint()
case reflect.String:
return vv.String()
default:
return v
}
}
normFirst := normalize(first)
for _, other := range others {
if e, ok := first.(compare.Eqer); ok {
if e.Eq(other) {
return true
}
continue
}
if e, ok := other.(compare.Eqer); ok {
if e.Eq(first) {
return true
}
continue
}
other = normalize(other)
if reflect.DeepEqual(normFirst, other) {
return true
}
}
return false
}
// Ne returns the boolean truth of arg1 != arg2 && arg1 != arg3 && arg1 != arg4.
func (n *Namespace) Ne(first interface{}, others ...interface{}) bool {
for _, other := range others {
if n.Eq(first, other) {
return false
}
}
return true
}
// Ge returns the boolean truth of arg1 >= arg2 && arg1 >= arg3 && arg1 >= arg4.
func (n *Namespace) Ge(first interface{}, others ...interface{}) bool {
for _, other := range others {
left, right := n.compareGet(first, other)
if !(left >= right) {
return false
}
}
return true
}
// Gt returns the boolean truth of arg1 > arg2 && arg1 > arg3 && arg1 > arg4.
func (n *Namespace) Gt(first interface{}, others ...interface{}) bool {
for _, other := range others {
left, right := n.compareGet(first, other)
if !(left > right) {
return false
}
}
return true
}
// Le returns the boolean truth of arg1 <= arg2 && arg1 <= arg3 && arg1 <= arg4.
func (n *Namespace) Le(first interface{}, others ...interface{}) bool {
for _, other := range others {
left, right := n.compareGet(first, other)
if !(left <= right) {
return false
}
}
return true
}
// Lt returns the boolean truth of arg1 < arg2 && arg1 < arg3 && arg1 < arg4.
func (n *Namespace) Lt(first interface{}, others ...interface{}) bool {
for _, other := range others {
left, right := n.compareGet(first, other)
if !(left < right) {
return false
}
}
return true
}
// Conditional can be used as a ternary operator.
// It returns a if condition, else b.
func (n *Namespace) Conditional(condition bool, a, b interface{}) interface{} {
if condition {
return a
}
return b
}
func (ns *Namespace) compareGet(a interface{}, b interface{}) (float64, float64) {
if ac, ok := a.(compare.Comparer); ok {
c := ac.Compare(b)
if c < 0 {
return 1, 0
} else if c == 0 {
return 0, 0
} else {
return 0, 1
}
}
if bc, ok := b.(compare.Comparer); ok {
c := bc.Compare(a)
if c < 0 {
return 0, 1
} else if c == 0 {
return 0, 0
} else {
return 1, 0
}
}
var left, right float64
var leftStr, rightStr *string
av := reflect.ValueOf(a)
switch av.Kind() {
case reflect.Array, reflect.Chan, reflect.Map, reflect.Slice:
left = float64(av.Len())
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
left = float64(av.Int())
case reflect.Float32, reflect.Float64:
left = av.Float()
case reflect.String:
var err error
left, err = strconv.ParseFloat(av.String(), 64)
if err != nil {
str := av.String()
leftStr = &str
}
case reflect.Struct:
switch av.Type() {
case timeType:
left = float64(toTimeUnix(av))
}
case reflect.Bool:
left = 0
if av.Bool() {
left = 1
}
}
bv := reflect.ValueOf(b)
switch bv.Kind() {
case reflect.Array, reflect.Chan, reflect.Map, reflect.Slice:
right = float64(bv.Len())
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
right = float64(bv.Int())
case reflect.Float32, reflect.Float64:
right = bv.Float()
case reflect.String:
var err error
right, err = strconv.ParseFloat(bv.String(), 64)
if err != nil {
str := bv.String()
rightStr = &str
}
case reflect.Struct:
switch bv.Type() {
case timeType:
right = float64(toTimeUnix(bv))
}
case reflect.Bool:
right = 0
if bv.Bool() {
right = 1
}
}
if ns.caseInsensitive && leftStr != nil && rightStr != nil {
c := compare.Strings(*leftStr, *rightStr)
if c < 0 {
return 0, 1
} else if c > 0 {
return 1, 0
} else {
return 0, 0
}
}
switch {
case leftStr == nil || rightStr == nil:
case *leftStr < *rightStr:
return 0, 1
case *leftStr > *rightStr:
return 1, 0
default:
return 0, 0
}
return left, right
}
var timeType = reflect.TypeOf((*time.Time)(nil)).Elem()
func toTimeUnix(v reflect.Value) int64 {
if v.Kind() == reflect.Interface {
return toTimeUnix(v.Elem())
}
if v.Type() != timeType {
panic("coding error: argument must be time.Time type reflect Value")
}
return v.MethodByName("Unix").Call([]reflect.Value{})[0].Int()
}