piframe-go/vendor/github.com/knadh/koanf/maps/maps.go

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2020-09-03 03:46:55 +00:00
// Package maps provides reusable functions for manipulating nested
// map[string]interface{} maps are common unmarshal products from
// various serializers such as json, yaml etc.
package maps
import (
"encoding/json"
"fmt"
"strings"
)
// Flatten takes a map[string]interface{} and traverses it and flattens
// nested children into keys delimited by delim.
//
// It's important to note that all nested maps should be
// map[string]interface{} and not map[interface{}]interface{}.
// Use IntfaceKeysToStrings() to convert if necessary.
//
// eg: `{ "parent": { "child": 123 }}` becomes `{ "parent.child": 123 }`
// In addition, it keeps track of and returns a map of the delimited keypaths with
// a slice of key parts, for eg: { "parent.child": ["parent", "child"] }. This
// parts list is used to remember the key path's original structure to
// unflatten later.
func Flatten(m map[string]interface{}, keys []string, delim string) (map[string]interface{}, map[string][]string) {
var (
out = make(map[string]interface{})
keyMap = make(map[string][]string)
)
for key, val := range m {
// Copy the incoming key paths into a fresh list
// and append the current key in the iteration.
kp := make([]string, 0, len(keys)+1)
kp = append(kp, keys...)
kp = append(kp, key)
switch cur := val.(type) {
case map[string]interface{}:
// Empty map.
if len(cur) == 0 {
newKey := strings.Join(kp, delim)
out[newKey] = val
keyMap[newKey] = kp
continue
}
// It's a nested map. Flatten it recursively.
next, parts := Flatten(cur, kp, delim)
// Copy the resultant key parts and the value maps.
for k, p := range parts {
keyMap[k] = p
}
for k, v := range next {
out[k] = v
}
default:
newKey := strings.Join(kp, delim)
out[newKey] = val
keyMap[newKey] = kp
}
}
return out, keyMap
}
// Unflatten takes a flattened key:value map (non-nested with delimited keys)
// and returns a nested map where the keys are split into hierarchies by the given
// delimiter. For instance, `parent.child.key: 1` to `{parent: {child: {key: 1}}}`
//
// It's important to note that all nested maps should be
// map[string]interface{} and not map[interface{}]interface{}.
// Use IntfaceKeysToStrings() to convert if necessary.
func Unflatten(m map[string]interface{}, delim string) map[string]interface{} {
out := make(map[string]interface{})
// Iterate through the flat conf map.
for k, v := range m {
var (
keys = strings.Split(k, delim)
next = out
)
// Iterate through key parts, for eg:, parent.child.key
// will be ["parent", "child", "key"]
for _, k := range keys[:len(keys)-1] {
sub, ok := next[k]
if !ok {
// If the key does not exist in the map, create it.
sub = make(map[string]interface{})
next[k] = sub
}
if n, ok := sub.(map[string]interface{}); ok {
next = n
}
}
// Assign the value.
next[keys[len(keys)-1]] = v
}
return out
}
// Merge recursively merges map a into b (left to right), mutating
// and expanding map b. Note that there's no copying involved, so
// map b will retain references to map a.
//
// It's important to note that all nested maps should be
// map[string]interface{} and not map[interface{}]interface{}.
// Use IntfaceKeysToStrings() to convert if necessary.
func Merge(a, b map[string]interface{}) {
for key, val := range a {
// Does the key exist in the target map?
// If no, add it and move on.
bVal, ok := b[key]
if !ok {
b[key] = val
continue
}
// If the incoming val is not a map, do a direct merge.
if _, ok := val.(map[string]interface{}); !ok {
b[key] = val
continue
}
// The source key and target keys are both maps. Merge them.
switch v := bVal.(type) {
case map[string]interface{}:
Merge(val.(map[string]interface{}), v)
default:
b[key] = val
}
}
}
// Search recursively searches a map for a given path. The path is
// the key map slice, for eg:, parent.child.key -> [parent child key].
//
// It's important to note that all nested maps should be
// map[string]interface{} and not map[interface{}]interface{}.
// Use IntfaceKeysToStrings() to convert if necessary.
func Search(mp map[string]interface{}, path []string) interface{} {
next, ok := mp[path[0]]
if ok {
if len(path) == 1 {
return next
}
switch next.(type) {
case map[string]interface{}:
return Search(next.(map[string]interface{}), path[1:])
default:
return nil
} //
// It's important to note that all nested maps should be
// map[string]interface{} and not map[interface{}]interface{}.
// Use IntfaceKeysToStrings() to convert if necessary.
}
return nil
}
// Copy returns a copy of a conf map by doing a JSON marshal+unmarshal
// pass. Inefficient, but creates a true deep copy. There is a side
// effect, that is, all numeric types change to float64.
//
// It's important to note that all nested maps should be
// map[string]interface{} and not map[interface{}]interface{}.
// Use IntfaceKeysToStrings() to convert if necessary.
func Copy(mp map[string]interface{}) map[string]interface{} {
var out map[string]interface{}
b, _ := json.Marshal(mp)
json.Unmarshal(b, &out)
return out
}
// IntfaceKeysToStrings recursively converts map[interface{}]interface{} to
// map[string]interface{}. Some parses such as YAML unmarshal return this.
func IntfaceKeysToStrings(mp map[string]interface{}) {
for key, val := range mp {
switch cur := val.(type) {
case map[interface{}]interface{}:
x := make(map[string]interface{})
for k, v := range cur {
x[fmt.Sprintf("%v", k)] = v
}
mp[key] = x
IntfaceKeysToStrings(x)
case []interface{}:
for i, v := range cur {
switch sub := v.(type) {
case map[interface{}]interface{}:
x := make(map[string]interface{})
for k, v := range sub {
x[fmt.Sprintf("%v", k)] = v
}
cur[i] = x
IntfaceKeysToStrings(x)
case map[string]interface{}:
IntfaceKeysToStrings(sub)
}
}
case map[string]interface{}:
IntfaceKeysToStrings(cur)
}
}
}
// StringSliceToLookupMap takes a slice of strings and returns a lookup map
// with the slice values as keys with true values.
func StringSliceToLookupMap(s []string) map[string]bool {
mp := make(map[string]bool, len(s))
for _, v := range s {
mp[v] = true
}
return mp
}
// Int64SliceToLookupMap takes a slice of int64s and returns a lookup map
// with the slice values as keys with true values.
func Int64SliceToLookupMap(s []int64) map[int64]bool {
mp := make(map[int64]bool, len(s))
for _, v := range s {
mp[v] = true
}
return mp
}