| 1 | // SPDX-License-Identifier: GPL-3.0-or-later |
| 2 | |
| 3 | package selectorcore |
| 4 | |
| 5 | import "fmt" |
| 6 | |
| 7 | // Expr is a selector expression with allow/deny selector lists. |
| 8 | type Expr struct { |
| 9 | Allow []string `yaml:"allow,omitempty" json:"allow"` |
| 10 | Deny []string `yaml:"deny,omitempty" json:"deny"` |
| 11 | } |
| 12 | |
| 13 | func (e Expr) Empty() bool { |
| 14 | return len(e.Allow) == 0 && len(e.Deny) == 0 |
| 15 | } |
| 16 | |
| 17 | func (e Expr) Parse() (Selector, error) { |
| 18 | if e.Empty() { |
| 19 | return nil, nil |
| 20 | } |
| 21 | |
| 22 | var ( |
| 23 | allow Selector = trueSelector{} |
| 24 | deny Selector = falseSelector{} |
| 25 | err error |
| 26 | ) |
| 27 | |
| 28 | if allow, err = parseSelectorList(e.Allow, trueSelector{}); err != nil { |
| 29 | return nil, err |
| 30 | } |
| 31 | if deny, err = parseSelectorList(e.Deny, falseSelector{}); err != nil { |
| 32 | return nil, err |
| 33 | } |
| 34 | return And(allow, Not(deny)), nil |
| 35 | } |
| 36 | |
| 37 | func parseSelectorList(items []string, fallback Selector) (Selector, error) { |
| 38 | srs := make([]Selector, 0, len(items)) |
| 39 | for _, item := range items { |
| 40 | sr, err := Parse(item) |
| 41 | if err != nil { |
| 42 | return nil, fmt.Errorf("parse selector %q: %w", item, err) |
| 43 | } |
| 44 | if sr == nil { |
| 45 | continue |
| 46 | } |
| 47 | srs = append(srs, sr) |
| 48 | } |
| 49 | switch len(srs) { |
| 50 | case 0: |
| 51 | return fallback, nil |
| 52 | case 1: |
| 53 | return srs[0], nil |
| 54 | default: |
| 55 | return Or(srs[0], srs[1], srs[2:]...), nil |
| 56 | } |
| 57 | } |