ref: 4e0acb89b793d8895dc53eb8887be27430c3ab31
dir: /tpl/collections/collections.go/
// Copyright 2019 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 collections provides template functions for manipulating collections
// such as arrays, maps, and slices.
package collections
import (
"fmt"
"html/template"
"math/rand"
"net/url"
"reflect"
"strings"
"time"
"github.com/gohugoio/hugo/common/collections"
"github.com/gohugoio/hugo/common/maps"
"github.com/gohugoio/hugo/common/types"
"github.com/gohugoio/hugo/deps"
"github.com/gohugoio/hugo/helpers"
"github.com/pkg/errors"
"github.com/spf13/cast"
)
func init() {
rand.Seed(time.Now().UTC().UnixNano())
}
// New returns a new instance of the collections-namespaced template functions.
func New(deps *deps.Deps) *Namespace {
return &Namespace{
deps: deps,
}
}
// Namespace provides template functions for the "collections" namespace.
type Namespace struct {
deps *deps.Deps
}
// After returns all the items after the first N in a rangeable list.
func (ns *Namespace) After(index interface{}, seq interface{}) (interface{}, error) {
if index == nil || seq == nil {
return nil, errors.New("both limit and seq must be provided")
}
indexv, err := cast.ToIntE(index)
if err != nil {
return nil, err
}
if indexv < 0 {
return nil, errors.New("sequence bounds out of range [" + cast.ToString(indexv) + ":]")
}
seqv := reflect.ValueOf(seq)
seqv, isNil := indirect(seqv)
if isNil {
return nil, errors.New("can't iterate over a nil value")
}
switch seqv.Kind() {
case reflect.Array, reflect.Slice, reflect.String:
// okay
default:
return nil, errors.New("can't iterate over " + reflect.ValueOf(seq).Type().String())
}
if indexv >= seqv.Len() {
return seqv.Slice(0, 0).Interface(), nil
}
return seqv.Slice(indexv, seqv.Len()).Interface(), nil
}
// Delimit takes a given sequence and returns a delimited HTML string.
// If last is passed to the function, it will be used as the final delimiter.
func (ns *Namespace) Delimit(seq, delimiter interface{}, last ...interface{}) (template.HTML, error) {
d, err := cast.ToStringE(delimiter)
if err != nil {
return "", err
}
var dLast *string
if len(last) > 0 {
l := last[0]
dStr, err := cast.ToStringE(l)
if err != nil {
dLast = nil
} else {
dLast = &dStr
}
}
seqv := reflect.ValueOf(seq)
seqv, isNil := indirect(seqv)
if isNil {
return "", errors.New("can't iterate over a nil value")
}
var str string
switch seqv.Kind() {
case reflect.Map:
sortSeq, err := ns.Sort(seq)
if err != nil {
return "", err
}
seqv = reflect.ValueOf(sortSeq)
fallthrough
case reflect.Array, reflect.Slice, reflect.String:
for i := 0; i < seqv.Len(); i++ {
val := seqv.Index(i).Interface()
valStr, err := cast.ToStringE(val)
if err != nil {
continue
}
switch {
case i == seqv.Len()-2 && dLast != nil:
str += valStr + *dLast
case i == seqv.Len()-1:
str += valStr
default:
str += valStr + d
}
}
default:
return "", fmt.Errorf("can't iterate over %v", seq)
}
return template.HTML(str), nil
}
// Dictionary creates a map[string]interface{} from the given parameters by
// walking the parameters and treating them as key-value pairs. The number
// of parameters must be even.
// The keys can be string slices, which will create the needed nested structure.
func (ns *Namespace) Dictionary(values ...interface{}) (map[string]interface{}, error) {
if len(values)%2 != 0 {
return nil, errors.New("invalid dictionary call")
}
root := make(map[string]interface{})
for i := 0; i < len(values); i += 2 {
dict := root
var key string
switch v := values[i].(type) {
case string:
key = v
case []string:
for i := 0; i < len(v)-1; i++ {
key = v[i]
var m map[string]interface{}
v, found := dict[key]
if found {
m = v.(map[string]interface{})
} else {
m = make(map[string]interface{})
dict[key] = m
}
dict = m
}
key = v[len(v)-1]
default:
return nil, errors.New("invalid dictionary key")
}
dict[key] = values[i+1]
}
return root, nil
}
// EchoParam returns a given value if it is set; otherwise, it returns an
// empty string.
func (ns *Namespace) EchoParam(a, key interface{}) interface{} {
av, isNil := indirect(reflect.ValueOf(a))
if isNil {
return ""
}
var avv reflect.Value
switch av.Kind() {
case reflect.Array, reflect.Slice:
index, ok := key.(int)
if ok && av.Len() > index {
avv = av.Index(index)
}
case reflect.Map:
kv := reflect.ValueOf(key)
if kv.Type().AssignableTo(av.Type().Key()) {
avv = av.MapIndex(kv)
}
}
avv, isNil = indirect(avv)
if isNil {
return ""
}
if avv.IsValid() {
switch avv.Kind() {
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
return avv.Int()
case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
return avv.Uint()
case reflect.Float32, reflect.Float64:
return avv.Float()
case reflect.String:
return avv.String()
}
}
return ""
}
// First returns the first N items in a rangeable list.
func (ns *Namespace) First(limit interface{}, seq interface{}) (interface{}, error) {
if limit == nil || seq == nil {
return nil, errors.New("both limit and seq must be provided")
}
limitv, err := cast.ToIntE(limit)
if err != nil {
return nil, err
}
if limitv < 0 {
return nil, errors.New("sequence length must be non-negative")
}
seqv := reflect.ValueOf(seq)
seqv, isNil := indirect(seqv)
if isNil {
return nil, errors.New("can't iterate over a nil value")
}
switch seqv.Kind() {
case reflect.Array, reflect.Slice, reflect.String:
// okay
default:
return nil, errors.New("can't iterate over " + reflect.ValueOf(seq).Type().String())
}
if limitv > seqv.Len() {
limitv = seqv.Len()
}
return seqv.Slice(0, limitv).Interface(), nil
}
// In returns whether v is in the set l. l may be an array or slice.
func (ns *Namespace) In(l interface{}, v interface{}) (bool, error) {
if l == nil || v == nil {
return false, nil
}
lv := reflect.ValueOf(l)
vv := reflect.ValueOf(v)
vvk := normalize(vv)
switch lv.Kind() {
case reflect.Array, reflect.Slice:
for i := 0; i < lv.Len(); i++ {
lvv, isNil := indirectInterface(lv.Index(i))
if isNil {
continue
}
lvvk := normalize(lvv)
if lvvk == vvk {
return true, nil
}
}
}
ss, err := cast.ToStringE(l)
if err != nil {
return false, nil
}
su, err := cast.ToStringE(v)
if err != nil {
return false, nil
}
return strings.Contains(ss, su), nil
}
// Intersect returns the common elements in the given sets, l1 and l2. l1 and
// l2 must be of the same type and may be either arrays or slices.
func (ns *Namespace) Intersect(l1, l2 interface{}) (interface{}, error) {
if l1 == nil || l2 == nil {
return make([]interface{}, 0), nil
}
var ins *intersector
l1v := reflect.ValueOf(l1)
l2v := reflect.ValueOf(l2)
switch l1v.Kind() {
case reflect.Array, reflect.Slice:
ins = &intersector{r: reflect.MakeSlice(l1v.Type(), 0, 0), seen: make(map[interface{}]bool)}
switch l2v.Kind() {
case reflect.Array, reflect.Slice:
for i := 0; i < l1v.Len(); i++ {
l1vv := l1v.Index(i)
if !l1vv.Type().Comparable() {
return make([]interface{}, 0), errors.New("intersect does not support slices or arrays of uncomparable types")
}
for j := 0; j < l2v.Len(); j++ {
l2vv := l2v.Index(j)
if !l2vv.Type().Comparable() {
return make([]interface{}, 0), errors.New("intersect does not support slices or arrays of uncomparable types")
}
ins.handleValuePair(l1vv, l2vv)
}
}
return ins.r.Interface(), nil
default:
return nil, errors.New("can't iterate over " + reflect.ValueOf(l2).Type().String())
}
default:
return nil, errors.New("can't iterate over " + reflect.ValueOf(l1).Type().String())
}
}
// Group groups a set of elements by the given key.
// This is currently only supported for Pages.
func (ns *Namespace) Group(key interface{}, items interface{}) (interface{}, error) {
if key == nil {
return nil, errors.New("nil is not a valid key to group by")
}
if g, ok := items.(collections.Grouper); ok {
return g.Group(key, items)
}
in := newSliceElement(items)
if g, ok := in.(collections.Grouper); ok {
return g.Group(key, items)
}
return nil, fmt.Errorf("grouping not supported for type %T %T", items, in)
}
// IsSet returns whether a given array, channel, slice, or map has a key
// defined.
func (ns *Namespace) IsSet(a interface{}, key interface{}) (bool, error) {
av := reflect.ValueOf(a)
kv := reflect.ValueOf(key)
switch av.Kind() {
case reflect.Array, reflect.Chan, reflect.Slice:
k, err := cast.ToIntE(key)
if err != nil {
return false, fmt.Errorf("isset unable to use key of type %T as index", key)
}
if av.Len() > k {
return true, nil
}
case reflect.Map:
if kv.Type() == av.Type().Key() {
return av.MapIndex(kv).IsValid(), nil
}
default:
helpers.DistinctFeedbackLog.Printf("WARNING: calling IsSet with unsupported type %q (%T) will always return false.\n", av.Kind(), a)
}
return false, nil
}
// Last returns the last N items in a rangeable list.
func (ns *Namespace) Last(limit interface{}, seq interface{}) (interface{}, error) {
if limit == nil || seq == nil {
return nil, errors.New("both limit and seq must be provided")
}
limitv, err := cast.ToIntE(limit)
if err != nil {
return nil, err
}
if limitv < 0 {
return nil, errors.New("sequence length must be non-negative")
}
seqv := reflect.ValueOf(seq)
seqv, isNil := indirect(seqv)
if isNil {
return nil, errors.New("can't iterate over a nil value")
}
switch seqv.Kind() {
case reflect.Array, reflect.Slice, reflect.String:
// okay
default:
return nil, errors.New("can't iterate over " + reflect.ValueOf(seq).Type().String())
}
if limitv > seqv.Len() {
limitv = seqv.Len()
}
return seqv.Slice(seqv.Len()-limitv, seqv.Len()).Interface(), nil
}
// Querify encodes the given parameters in URL-encoded form ("bar=baz&foo=quux") sorted by key.
func (ns *Namespace) Querify(params ...interface{}) (string, error) {
qs := url.Values{}
vals, err := ns.Dictionary(params...)
if err != nil {
return "", errors.New("querify keys must be strings")
}
for name, value := range vals {
qs.Add(name, fmt.Sprintf("%v", value))
}
return qs.Encode(), nil
}
// Reverse creates a copy of slice and reverses it.
func (ns *Namespace) Reverse(slice interface{}) (interface{}, error) {
if slice == nil {
return nil, nil
}
v := reflect.ValueOf(slice)
switch v.Kind() {
case reflect.Slice:
default:
return nil, errors.New("argument must be a slice")
}
sliceCopy := reflect.MakeSlice(v.Type(), v.Len(), v.Len())
for i := v.Len() - 1; i >= 0; i-- {
element := sliceCopy.Index(i)
element.Set(v.Index(v.Len() - 1 - i))
}
return sliceCopy.Interface(), nil
}
// Seq creates a sequence of integers. It's named and used as GNU's seq.
//
// Examples:
// 3 => 1, 2, 3
// 1 2 4 => 1, 3
// -3 => -1, -2, -3
// 1 4 => 1, 2, 3, 4
// 1 -2 => 1, 0, -1, -2
func (ns *Namespace) Seq(args ...interface{}) ([]int, error) {
if len(args) < 1 || len(args) > 3 {
return nil, errors.New("invalid number of arguments to Seq")
}
intArgs := cast.ToIntSlice(args)
if len(intArgs) < 1 || len(intArgs) > 3 {
return nil, errors.New("invalid arguments to Seq")
}
inc := 1
var last int
first := intArgs[0]
if len(intArgs) == 1 {
last = first
if last == 0 {
return []int{}, nil
} else if last > 0 {
first = 1
} else {
first = -1
inc = -1
}
} else if len(intArgs) == 2 {
last = intArgs[1]
if last < first {
inc = -1
}
} else {
inc = intArgs[1]
last = intArgs[2]
if inc == 0 {
return nil, errors.New("'increment' must not be 0")
}
if first < last && inc < 0 {
return nil, errors.New("'increment' must be > 0")
}
if first > last && inc > 0 {
return nil, errors.New("'increment' must be < 0")
}
}
// sanity check
if last < -100000 {
return nil, errors.New("size of result exceeds limit")
}
size := ((last - first) / inc) + 1
// sanity check
if size <= 0 || size > 2000 {
return nil, errors.New("size of result exceeds limit")
}
seq := make([]int, size)
val := first
for i := 0; ; i++ {
seq[i] = val
val += inc
if (inc < 0 && val < last) || (inc > 0 && val > last) {
break
}
}
return seq, nil
}
// Shuffle returns the given rangeable list in a randomised order.
func (ns *Namespace) Shuffle(seq interface{}) (interface{}, error) {
if seq == nil {
return nil, errors.New("both count and seq must be provided")
}
seqv := reflect.ValueOf(seq)
seqv, isNil := indirect(seqv)
if isNil {
return nil, errors.New("can't iterate over a nil value")
}
switch seqv.Kind() {
case reflect.Array, reflect.Slice, reflect.String:
// okay
default:
return nil, errors.New("can't iterate over " + reflect.ValueOf(seq).Type().String())
}
shuffled := reflect.MakeSlice(reflect.TypeOf(seq), seqv.Len(), seqv.Len())
randomIndices := rand.Perm(seqv.Len())
for index, value := range randomIndices {
shuffled.Index(value).Set(seqv.Index(index))
}
return shuffled.Interface(), nil
}
// Slice returns a slice of all passed arguments.
func (ns *Namespace) Slice(args ...interface{}) interface{} {
if len(args) == 0 {
return args
}
return collections.Slice(args...)
}
type intersector struct {
r reflect.Value
seen map[interface{}]bool
}
func (i *intersector) appendIfNotSeen(v reflect.Value) {
vi := v.Interface()
if !i.seen[vi] {
i.r = reflect.Append(i.r, v)
i.seen[vi] = true
}
}
func (i *intersector) handleValuePair(l1vv, l2vv reflect.Value) {
switch kind := l1vv.Kind(); {
case kind == reflect.String:
l2t, err := toString(l2vv)
if err == nil && l1vv.String() == l2t {
i.appendIfNotSeen(l1vv)
}
case isNumber(kind):
f1, err1 := numberToFloat(l1vv)
f2, err2 := numberToFloat(l2vv)
if err1 == nil && err2 == nil && f1 == f2 {
i.appendIfNotSeen(l1vv)
}
case kind == reflect.Ptr, kind == reflect.Struct:
if l1vv.Interface() == l2vv.Interface() {
i.appendIfNotSeen(l1vv)
}
case kind == reflect.Interface:
i.handleValuePair(reflect.ValueOf(l1vv.Interface()), l2vv)
}
}
// Union returns the union of the given sets, l1 and l2. l1 and
// l2 must be of the same type and may be either arrays or slices.
// If l1 and l2 aren't of the same type then l1 will be returned.
// If either l1 or l2 is nil then the non-nil list will be returned.
func (ns *Namespace) Union(l1, l2 interface{}) (interface{}, error) {
if l1 == nil && l2 == nil {
return []interface{}{}, nil
} else if l1 == nil && l2 != nil {
return l2, nil
} else if l1 != nil && l2 == nil {
return l1, nil
}
l1v := reflect.ValueOf(l1)
l2v := reflect.ValueOf(l2)
var ins *intersector
switch l1v.Kind() {
case reflect.Array, reflect.Slice:
switch l2v.Kind() {
case reflect.Array, reflect.Slice:
ins = &intersector{r: reflect.MakeSlice(l1v.Type(), 0, 0), seen: make(map[interface{}]bool)}
if l1v.Type() != l2v.Type() &&
l1v.Type().Elem().Kind() != reflect.Interface &&
l2v.Type().Elem().Kind() != reflect.Interface {
return ins.r.Interface(), nil
}
var (
l1vv reflect.Value
isNil bool
)
for i := 0; i < l1v.Len(); i++ {
l1vv, isNil = indirectInterface(l1v.Index(i))
if !l1vv.Type().Comparable() {
return []interface{}{}, errors.New("union does not support slices or arrays of uncomparable types")
}
if !isNil {
ins.appendIfNotSeen(l1vv)
}
}
if !l1vv.IsValid() {
// The first slice may be empty. Pick the first value of the second
// to use as a prototype.
if l2v.Len() > 0 {
l1vv = l2v.Index(0)
}
}
for j := 0; j < l2v.Len(); j++ {
l2vv := l2v.Index(j)
switch kind := l1vv.Kind(); {
case kind == reflect.String:
l2t, err := toString(l2vv)
if err == nil {
ins.appendIfNotSeen(reflect.ValueOf(l2t))
}
case isNumber(kind):
var err error
l2vv, err = convertNumber(l2vv, kind)
if err == nil {
ins.appendIfNotSeen(l2vv)
}
case kind == reflect.Interface, kind == reflect.Struct, kind == reflect.Ptr:
ins.appendIfNotSeen(l2vv)
}
}
return ins.r.Interface(), nil
default:
return nil, errors.New("can't iterate over " + reflect.ValueOf(l2).Type().String())
}
default:
return nil, errors.New("can't iterate over " + reflect.ValueOf(l1).Type().String())
}
}
// Uniq takes in a slice or array and returns a slice with subsequent
// duplicate elements removed.
func (ns *Namespace) Uniq(seq interface{}) (interface{}, error) {
if seq == nil {
return make([]interface{}, 0), nil
}
v := reflect.ValueOf(seq)
var slice reflect.Value
switch v.Kind() {
case reflect.Slice:
slice = reflect.MakeSlice(v.Type(), 0, 0)
case reflect.Array:
slice = reflect.MakeSlice(reflect.SliceOf(v.Type().Elem()), 0, 0)
default:
return nil, errors.Errorf("type %T not supported", seq)
}
seen := make(map[interface{}]bool)
for i := 0; i < v.Len(); i++ {
ev, _ := indirectInterface(v.Index(i))
key := normalize(ev)
if _, found := seen[key]; !found {
slice = reflect.Append(slice, ev)
seen[key] = true
}
}
return slice.Interface(), nil
}
// KeyVals creates a key and values wrapper.
func (ns *Namespace) KeyVals(key interface{}, vals ...interface{}) (types.KeyValues, error) {
return types.KeyValues{Key: key, Values: vals}, nil
}
// NewScratch creates a new Scratch which can be used to store values in a
// thread safe way.
func (ns *Namespace) NewScratch() *maps.Scratch {
return maps.NewScratch()
}