mirror of
https://github.com/gohugoio/hugo.git
synced 2024-11-21 20:46:30 -05:00
431 lines
11 KiB
Go
431 lines
11 KiB
Go
// Copyright 2017 The Hugo Authors. All rights reserved.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package collections
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import (
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"errors"
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"fmt"
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"reflect"
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"strings"
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"time"
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)
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// Where returns a filtered subset of a given data type.
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func (ns *Namespace) Where(seq, key interface{}, args ...interface{}) (interface{}, error) {
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seqv, isNil := indirect(reflect.ValueOf(seq))
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if isNil {
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return nil, errors.New("can't iterate over a nil value of type " + reflect.ValueOf(seq).Type().String())
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}
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mv, op, err := parseWhereArgs(args...)
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if err != nil {
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return nil, err
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}
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var path []string
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kv := reflect.ValueOf(key)
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if kv.Kind() == reflect.String {
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path = strings.Split(strings.Trim(kv.String(), "."), ".")
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}
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switch seqv.Kind() {
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case reflect.Array, reflect.Slice:
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return ns.checkWhereArray(seqv, kv, mv, path, op)
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case reflect.Map:
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return ns.checkWhereMap(seqv, kv, mv, path, op)
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default:
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return nil, fmt.Errorf("can't iterate over %v", seq)
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}
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}
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func (ns *Namespace) checkCondition(v, mv reflect.Value, op string) (bool, error) {
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v, vIsNil := indirect(v)
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if !v.IsValid() {
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vIsNil = true
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}
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mv, mvIsNil := indirect(mv)
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if !mv.IsValid() {
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mvIsNil = true
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}
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if vIsNil || mvIsNil {
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switch op {
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case "", "=", "==", "eq":
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return vIsNil == mvIsNil, nil
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case "!=", "<>", "ne":
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return vIsNil != mvIsNil, nil
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}
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return false, nil
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}
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if v.Kind() == reflect.Bool && mv.Kind() == reflect.Bool {
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switch op {
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case "", "=", "==", "eq":
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return v.Bool() == mv.Bool(), nil
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case "!=", "<>", "ne":
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return v.Bool() != mv.Bool(), nil
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}
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return false, nil
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}
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var ivp, imvp *int64
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var svp, smvp *string
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var slv, slmv interface{}
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var ima []int64
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var sma []string
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if mv.Type() == v.Type() {
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switch v.Kind() {
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case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
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iv := v.Int()
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ivp = &iv
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imv := mv.Int()
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imvp = &imv
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case reflect.String:
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sv := v.String()
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svp = &sv
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smv := mv.String()
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smvp = &smv
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case reflect.Struct:
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switch v.Type() {
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case timeType:
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iv := toTimeUnix(v)
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ivp = &iv
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imv := toTimeUnix(mv)
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imvp = &imv
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}
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case reflect.Array, reflect.Slice:
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slv = v.Interface()
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slmv = mv.Interface()
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}
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} else {
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if mv.Kind() != reflect.Array && mv.Kind() != reflect.Slice {
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return false, nil
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}
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if mv.Len() == 0 {
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return false, nil
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}
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if v.Kind() != reflect.Interface && mv.Type().Elem().Kind() != reflect.Interface && mv.Type().Elem() != v.Type() {
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return false, nil
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}
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switch v.Kind() {
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case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
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iv := v.Int()
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ivp = &iv
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for i := 0; i < mv.Len(); i++ {
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if anInt, err := toInt(mv.Index(i)); err == nil {
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ima = append(ima, anInt)
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}
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}
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case reflect.String:
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sv := v.String()
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svp = &sv
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for i := 0; i < mv.Len(); i++ {
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if aString, err := toString(mv.Index(i)); err == nil {
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sma = append(sma, aString)
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}
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}
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case reflect.Struct:
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switch v.Type() {
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case timeType:
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iv := toTimeUnix(v)
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ivp = &iv
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for i := 0; i < mv.Len(); i++ {
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ima = append(ima, toTimeUnix(mv.Index(i)))
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}
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}
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}
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}
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switch op {
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case "", "=", "==", "eq":
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if ivp != nil && imvp != nil {
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return *ivp == *imvp, nil
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} else if svp != nil && smvp != nil {
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return *svp == *smvp, nil
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}
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case "!=", "<>", "ne":
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if ivp != nil && imvp != nil {
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return *ivp != *imvp, nil
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} else if svp != nil && smvp != nil {
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return *svp != *smvp, nil
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}
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case ">=", "ge":
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if ivp != nil && imvp != nil {
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return *ivp >= *imvp, nil
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} else if svp != nil && smvp != nil {
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return *svp >= *smvp, nil
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}
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case ">", "gt":
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if ivp != nil && imvp != nil {
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return *ivp > *imvp, nil
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} else if svp != nil && smvp != nil {
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return *svp > *smvp, nil
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}
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case "<=", "le":
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if ivp != nil && imvp != nil {
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return *ivp <= *imvp, nil
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} else if svp != nil && smvp != nil {
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return *svp <= *smvp, nil
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}
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case "<", "lt":
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if ivp != nil && imvp != nil {
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return *ivp < *imvp, nil
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} else if svp != nil && smvp != nil {
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return *svp < *smvp, nil
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}
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case "in", "not in":
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var r bool
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if ivp != nil && len(ima) > 0 {
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r = ns.In(ima, *ivp)
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} else if svp != nil {
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if len(sma) > 0 {
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r = ns.In(sma, *svp)
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} else if smvp != nil {
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r = ns.In(*smvp, *svp)
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}
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} else {
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return false, nil
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}
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if op == "not in" {
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return !r, nil
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}
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return r, nil
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case "intersect":
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r, err := ns.Intersect(slv, slmv)
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if err != nil {
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return false, err
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}
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if reflect.TypeOf(r).Kind() == reflect.Slice {
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s := reflect.ValueOf(r)
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if s.Len() > 0 {
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return true, nil
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}
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return false, nil
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}
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return false, errors.New("invalid intersect values")
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default:
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return false, errors.New("no such operator")
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}
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return false, nil
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}
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func evaluateSubElem(obj reflect.Value, elemName string) (reflect.Value, error) {
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if !obj.IsValid() {
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return zero, errors.New("can't evaluate an invalid value")
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}
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typ := obj.Type()
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obj, isNil := indirect(obj)
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// first, check whether obj has a method. In this case, obj is
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// an interface, a struct or its pointer. If obj is a struct,
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// to check all T and *T method, use obj pointer type Value
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objPtr := obj
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if objPtr.Kind() != reflect.Interface && objPtr.CanAddr() {
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objPtr = objPtr.Addr()
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}
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mt, ok := objPtr.Type().MethodByName(elemName)
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if ok {
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if mt.PkgPath != "" {
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return zero, fmt.Errorf("%s is an unexported method of type %s", elemName, typ)
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}
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// struct pointer has one receiver argument and interface doesn't have an argument
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if mt.Type.NumIn() > 1 || mt.Type.NumOut() == 0 || mt.Type.NumOut() > 2 {
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return zero, fmt.Errorf("%s is a method of type %s but doesn't satisfy requirements", elemName, typ)
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}
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if mt.Type.NumOut() == 1 && mt.Type.Out(0).Implements(errorType) {
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return zero, fmt.Errorf("%s is a method of type %s but doesn't satisfy requirements", elemName, typ)
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}
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if mt.Type.NumOut() == 2 && !mt.Type.Out(1).Implements(errorType) {
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return zero, fmt.Errorf("%s is a method of type %s but doesn't satisfy requirements", elemName, typ)
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}
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res := objPtr.Method(mt.Index).Call([]reflect.Value{})
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if len(res) == 2 && !res[1].IsNil() {
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return zero, fmt.Errorf("error at calling a method %s of type %s: %s", elemName, typ, res[1].Interface().(error))
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}
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return res[0], nil
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}
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// elemName isn't a method so next start to check whether it is
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// a struct field or a map value. In both cases, it mustn't be
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// a nil value
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if isNil {
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return zero, fmt.Errorf("can't evaluate a nil pointer of type %s by a struct field or map key name %s", typ, elemName)
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}
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switch obj.Kind() {
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case reflect.Struct:
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ft, ok := obj.Type().FieldByName(elemName)
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if ok {
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if ft.PkgPath != "" && !ft.Anonymous {
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return zero, fmt.Errorf("%s is an unexported field of struct type %s", elemName, typ)
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}
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return obj.FieldByIndex(ft.Index), nil
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}
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return zero, fmt.Errorf("%s isn't a field of struct type %s", elemName, typ)
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case reflect.Map:
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kv := reflect.ValueOf(elemName)
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if kv.Type().AssignableTo(obj.Type().Key()) {
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return obj.MapIndex(kv), nil
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}
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return zero, fmt.Errorf("%s isn't a key of map type %s", elemName, typ)
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}
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return zero, fmt.Errorf("%s is neither a struct field, a method nor a map element of type %s", elemName, typ)
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}
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// parseWhereArgs parses the end arguments to the where function. Return a
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// match value and an operator, if one is defined.
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func parseWhereArgs(args ...interface{}) (mv reflect.Value, op string, err error) {
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switch len(args) {
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case 1:
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mv = reflect.ValueOf(args[0])
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case 2:
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var ok bool
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if op, ok = args[0].(string); !ok {
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err = errors.New("operator argument must be string type")
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return
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}
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op = strings.TrimSpace(strings.ToLower(op))
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mv = reflect.ValueOf(args[1])
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default:
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err = errors.New("can't evaluate the array by no match argument or more than or equal to two arguments")
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}
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return
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}
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// checkWhereArray handles the where-matching logic when the seqv value is an
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// Array or Slice.
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func (ns *Namespace) checkWhereArray(seqv, kv, mv reflect.Value, path []string, op string) (interface{}, error) {
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rv := reflect.MakeSlice(seqv.Type(), 0, 0)
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for i := 0; i < seqv.Len(); i++ {
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var vvv reflect.Value
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rvv := seqv.Index(i)
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if kv.Kind() == reflect.String {
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vvv = rvv
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for _, elemName := range path {
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var err error
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vvv, err = evaluateSubElem(vvv, elemName)
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if err != nil {
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return nil, err
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}
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}
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} else {
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vv, _ := indirect(rvv)
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if vv.Kind() == reflect.Map && kv.Type().AssignableTo(vv.Type().Key()) {
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vvv = vv.MapIndex(kv)
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}
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}
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if ok, err := ns.checkCondition(vvv, mv, op); ok {
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rv = reflect.Append(rv, rvv)
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} else if err != nil {
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return nil, err
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}
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}
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return rv.Interface(), nil
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}
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// checkWhereMap handles the where-matching logic when the seqv value is a Map.
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func (ns *Namespace) checkWhereMap(seqv, kv, mv reflect.Value, path []string, op string) (interface{}, error) {
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rv := reflect.MakeMap(seqv.Type())
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keys := seqv.MapKeys()
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for _, k := range keys {
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elemv := seqv.MapIndex(k)
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switch elemv.Kind() {
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case reflect.Array, reflect.Slice:
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r, err := ns.checkWhereArray(elemv, kv, mv, path, op)
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if err != nil {
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return nil, err
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}
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switch rr := reflect.ValueOf(r); rr.Kind() {
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case reflect.Slice:
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if rr.Len() > 0 {
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rv.SetMapIndex(k, elemv)
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}
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}
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case reflect.Interface:
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elemvv, isNil := indirect(elemv)
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if isNil {
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continue
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}
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switch elemvv.Kind() {
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case reflect.Array, reflect.Slice:
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r, err := ns.checkWhereArray(elemvv, kv, mv, path, op)
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if err != nil {
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return nil, err
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}
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switch rr := reflect.ValueOf(r); rr.Kind() {
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case reflect.Slice:
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if rr.Len() > 0 {
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rv.SetMapIndex(k, elemv)
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}
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}
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}
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}
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}
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return rv.Interface(), nil
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}
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// toFloat returns the int value if possible.
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func toFloat(v reflect.Value) (float64, error) {
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switch v.Kind() {
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case reflect.Float32, reflect.Float64:
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return v.Float(), nil
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case reflect.Interface:
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return toFloat(v.Elem())
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}
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return -1, errors.New("unable to convert value to float")
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}
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// toInt returns the int value if possible, -1 if not.
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func toInt(v reflect.Value) (int64, error) {
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switch v.Kind() {
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case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
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return v.Int(), nil
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case reflect.Interface:
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return toInt(v.Elem())
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}
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return -1, errors.New("unable to convert value to int")
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}
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// toString returns the string value if possible, "" if not.
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func toString(v reflect.Value) (string, error) {
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switch v.Kind() {
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case reflect.String:
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return v.String(), nil
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case reflect.Interface:
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return toString(v.Elem())
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}
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return "", errors.New("unable to convert value to string")
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}
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var (
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zero reflect.Value
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errorType = reflect.TypeOf((*error)(nil)).Elem()
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timeType = reflect.TypeOf((*time.Time)(nil)).Elem()
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)
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func toTimeUnix(v reflect.Value) int64 {
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if v.Kind() == reflect.Interface {
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return toTimeUnix(v.Elem())
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}
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if v.Type() != timeType {
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panic("coding error: argument must be time.Time type reflect Value")
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}
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return v.MethodByName("Unix").Call([]reflect.Value{})[0].Int()
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}
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