151 lines
3.6 KiB
Go
151 lines
3.6 KiB
Go
package policy
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// https://github.com/ucan-wg/delegation/blob/4094d5878b58f5d35055a3b93fccda0b8329ebae/README.md#policy
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import (
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"github.com/ipld/go-ipld-prime"
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"github.com/ucan-wg/go-ucan/pkg/policy/selector"
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)
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const (
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KindEqual = "==" // implemented by equality
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KindGreaterThan = ">" // implemented by equality
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KindGreaterThanOrEqual = ">=" // implemented by equality
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KindLessThan = "<" // implemented by equality
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KindLessThanOrEqual = "<=" // implemented by equality
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KindNot = "not" // implemented by negation
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KindAnd = "and" // implemented by connective
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KindOr = "or" // implemented by connective
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KindLike = "like" // implemented by wildcard
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KindAll = "all" // implemented by quantifier
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KindAny = "any" // implemented by quantifier
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)
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type Policy []Statement
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type Statement interface {
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Kind() string
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Selector() selector.Selector
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}
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type equality struct {
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kind string
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selector selector.Selector
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value ipld.Node
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}
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func (e equality) Kind() string {
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return e.kind
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}
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func (e equality) Selector() selector.Selector {
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return e.selector
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}
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func Equal(selector selector.Selector, value ipld.Node) Statement {
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return equality{kind: KindEqual, selector: selector, value: value}
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}
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func GreaterThan(selector selector.Selector, value ipld.Node) Statement {
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return equality{kind: KindGreaterThan, selector: selector, value: value}
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}
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func GreaterThanOrEqual(selector selector.Selector, value ipld.Node) Statement {
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return equality{kind: KindGreaterThanOrEqual, selector: selector, value: value}
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}
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func LessThan(selector selector.Selector, value ipld.Node) Statement {
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return equality{kind: KindLessThan, selector: selector, value: value}
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}
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func LessThanOrEqual(selector selector.Selector, value ipld.Node) Statement {
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return equality{kind: KindLessThanOrEqual, selector: selector, value: value}
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}
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type negation struct {
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statement Statement
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}
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func (n negation) Kind() string {
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return KindNot
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}
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func (n negation) Selector() selector.Selector {
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return n.statement.Selector()
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}
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func Not(stmt Statement) Statement {
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return negation{statement: stmt}
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}
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type connective struct {
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kind string
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statements []Statement
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}
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func (c connective) Kind() string {
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return c.kind
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}
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func (c connective) Selector() selector.Selector {
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// assuming the first statement's selector is representative
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if len(c.statements) > 0 {
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return c.statements[0].Selector()
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}
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return selector.Selector{}
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}
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func And(stmts ...Statement) Statement {
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return connective{kind: KindAnd, statements: stmts}
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}
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func Or(stmts ...Statement) Statement {
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return connective{kind: KindOr, statements: stmts}
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}
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type wildcard struct {
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selector selector.Selector
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pattern glob
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}
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func (n wildcard) Kind() string {
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return KindLike
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}
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func (n wildcard) Selector() selector.Selector {
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return n.selector
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}
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func Like(selector selector.Selector, pattern string) (Statement, error) {
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g, err := parseGlob(pattern)
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if err != nil {
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return nil, err
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}
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return wildcard{selector: selector, pattern: g}, nil
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}
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type quantifier struct {
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kind string
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selector selector.Selector
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statement Statement
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}
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func (n quantifier) Kind() string {
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return n.kind
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}
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func (n quantifier) Selector() selector.Selector {
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return n.selector
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}
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func All(selector selector.Selector, statement Statement) Statement {
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return quantifier{kind: KindAll, selector: selector, statement: statement}
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}
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func Any(selector selector.Selector, statement Statement) Statement {
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return quantifier{kind: KindAny, selector: selector, statement: statement}
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}
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