Matthias Andreas Benkard | 832a54e | 2019-01-29 09:27:38 +0100 | [diff] [blame] | 1 | /* |
| 2 | Copyright 2017 The Kubernetes Authors. |
| 3 | |
| 4 | Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | you may not use this file except in compliance with the License. |
| 6 | You may obtain a copy of the License at |
| 7 | |
| 8 | http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | |
| 10 | Unless required by applicable law or agreed to in writing, software |
| 11 | distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | See the License for the specific language governing permissions and |
| 14 | limitations under the License. |
| 15 | */ |
| 16 | |
| 17 | package flag |
| 18 | |
| 19 | import ( |
| 20 | "fmt" |
| 21 | "sort" |
| 22 | "strings" |
| 23 | ) |
| 24 | |
| 25 | // ColonSeparatedMultimapStringString supports setting a map[string][]string from an encoding |
| 26 | // that separates keys from values with ':' and separates key-value pairs with ','. |
| 27 | // A key can be repeated multiple times, in which case the values are appended to a |
| 28 | // slice of strings associated with that key. Items in the list associated with a given |
| 29 | // key will appear in the order provided. |
| 30 | // For example: `a:hello,b:again,c:world,b:beautiful` results in `{"a": ["hello"], "b": ["again", "beautiful"], "c": ["world"]}` |
| 31 | // The first call to Set will clear the map before adding entries; subsequent calls will simply append to the map. |
| 32 | // This makes it possible to override default values with a command-line option rather than appending to defaults, |
| 33 | // while still allowing the distribution of key-value pairs across multiple flag invocations. |
| 34 | // For example: `--flag "a:hello" --flag "b:again" --flag "b:beautiful" --flag "c:world"` results in `{"a": ["hello"], "b": ["again", "beautiful"], "c": ["world"]}` |
| 35 | type ColonSeparatedMultimapStringString struct { |
| 36 | Multimap *map[string][]string |
| 37 | initialized bool // set to true after the first Set call |
| 38 | } |
| 39 | |
| 40 | // NewColonSeparatedMultimapStringString takes a pointer to a map[string][]string and returns the |
| 41 | // ColonSeparatedMultimapStringString flag parsing shim for that map. |
| 42 | func NewColonSeparatedMultimapStringString(m *map[string][]string) *ColonSeparatedMultimapStringString { |
| 43 | return &ColonSeparatedMultimapStringString{Multimap: m} |
| 44 | } |
| 45 | |
| 46 | // Set implements github.com/spf13/pflag.Value |
| 47 | func (m *ColonSeparatedMultimapStringString) Set(value string) error { |
| 48 | if m.Multimap == nil { |
| 49 | return fmt.Errorf("no target (nil pointer to map[string][]string)") |
| 50 | } |
| 51 | if !m.initialized || *m.Multimap == nil { |
| 52 | // clear default values, or allocate if no existing map |
| 53 | *m.Multimap = make(map[string][]string) |
| 54 | m.initialized = true |
| 55 | } |
| 56 | for _, pair := range strings.Split(value, ",") { |
| 57 | if len(pair) == 0 { |
| 58 | continue |
| 59 | } |
| 60 | kv := strings.SplitN(pair, ":", 2) |
| 61 | if len(kv) != 2 { |
| 62 | return fmt.Errorf("malformed pair, expect string:string") |
| 63 | } |
| 64 | k := strings.TrimSpace(kv[0]) |
| 65 | v := strings.TrimSpace(kv[1]) |
| 66 | (*m.Multimap)[k] = append((*m.Multimap)[k], v) |
| 67 | } |
| 68 | return nil |
| 69 | } |
| 70 | |
| 71 | // String implements github.com/spf13/pflag.Value |
| 72 | func (m *ColonSeparatedMultimapStringString) String() string { |
| 73 | type kv struct { |
| 74 | k string |
| 75 | v string |
| 76 | } |
| 77 | kvs := make([]kv, 0, len(*m.Multimap)) |
| 78 | for k, vs := range *m.Multimap { |
| 79 | for i := range vs { |
| 80 | kvs = append(kvs, kv{k: k, v: vs[i]}) |
| 81 | } |
| 82 | } |
| 83 | // stable sort by keys, order of values should be preserved |
| 84 | sort.SliceStable(kvs, func(i, j int) bool { |
| 85 | return kvs[i].k < kvs[j].k |
| 86 | }) |
| 87 | pairs := make([]string, 0, len(kvs)) |
| 88 | for i := range kvs { |
| 89 | pairs = append(pairs, fmt.Sprintf("%s:%s", kvs[i].k, kvs[i].v)) |
| 90 | } |
| 91 | return strings.Join(pairs, ",") |
| 92 | } |
| 93 | |
| 94 | // Type implements github.com/spf13/pflag.Value |
| 95 | func (m *ColonSeparatedMultimapStringString) Type() string { |
| 96 | return "colonSeparatedMultimapStringString" |
| 97 | } |
| 98 | |
| 99 | // Empty implements OmitEmpty |
| 100 | func (m *ColonSeparatedMultimapStringString) Empty() bool { |
| 101 | return len(*m.Multimap) == 0 |
| 102 | } |