glob: a bit of reshaping, and a benchmark

capability/policy/glob.go

@@ -1,7 +1,11 @@
 package policy
 
-// validateGlobPattern ensures the pattern conforms to the spec: only '*' and escaped '\*' are allowed.
-func validateGlobPattern(pattern string) bool {
+import "fmt"
+
+type glob string
+
+// parseGlob ensures that the pattern conforms to the spec: only '*' and escaped '\*' are allowed.
+func parseGlob(pattern string) (glob, error) {
 	for i := 0; i < len(pattern); i++ {
 		if pattern[i] == '*' {
 			continue
@@ -15,15 +19,23 @@ func validateGlobPattern(pattern string) bool {
 			continue
 		}
 		if pattern[i] == '\\' {
-			return false // invalid escape sequence
+			return "", fmt.Errorf("invalid escape sequence")
 		}
 	}
 
-	return true
+	return glob(pattern), nil
+}
+
+func mustParseGlob(pattern string) glob {
+	g, err := parseGlob(pattern)
+	if err != nil {
+		panic(err)
+	}
+	return g
 }
 
-// globMatch matches a string against a pattern with * wildcards, handling escaped '\*' literals.
-func globMatch(pattern, str string) bool {
+// Match matches a string against the glob pattern with * wildcards, handling escaped '\*' literals.
+func (pattern glob) Match(str string) bool {
 	// i is the index for the pattern
 	// j is the index for the string
 	var i, j int

capability/policy/glob_test.go

@@ -3,7 +3,7 @@ package policy
 import (
 	"testing"
 
-	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 )
 
 func TestSimpleGlobMatch(t *testing.T) {
@@ -56,7 +56,18 @@ func TestSimpleGlobMatch(t *testing.T) {
 
 	for _, tt := range tests {
 		t.Run(tt.pattern+"_"+tt.str, func(t *testing.T) {
-			assert.Equal(t, tt.matches, globMatch(tt.pattern, tt.str))
+			g, err := parseGlob(tt.pattern)
+			require.NoError(t, err)
+			require.Equal(t, tt.matches, g.Match(tt.str))
 		})
 	}
 }
+
+func BenchmarkGlob(b *testing.B) {
+	b.ReportAllocs()
+
+	for i := 0; i < b.N; i++ {
+		g := mustParseGlob("Alice\\*, Bob*, Carol.")
+		g.Match("Alice*, Bob*, Carol!")
+	}
+}

capability/policy/match.go

@@ -112,7 +112,7 @@ func matchStatement(statement Statement, node ipld.Node) bool {
 			if err != nil {
 				return false
 			}
-			return s.pattern.match(v)
+			return s.pattern.Match(v)
 		}
 	case KindAll:
 		if s, ok := statement.(quantifier); ok {

capability/policy/policy.go

@@ -3,8 +3,6 @@ package policy
 // https://github.com/ucan-wg/delegation/blob/4094d5878b58f5d35055a3b93fccda0b8329ebae/README.md#policy
 
 import (
-	"errors"
-
 	"github.com/ipld/go-ipld-prime"
 
 	"github.com/ucan-wg/go-ucan/capability/policy/selector"
@@ -89,36 +87,22 @@ func Or(stmts ...Statement) Statement {
 	return connective{kind: KindOr, statements: stmts}
 }
 
-type wildcardPattern string
-
-func parseWildcardPattern(pattern string) (wildcardPattern, error) {
-	if !validateGlobPattern(pattern) {
-		return "", errors.New("invalid wildcard pattern")
-	}
-
-	return wildcardPattern(pattern), nil
-}
-
-func (wp wildcardPattern) match(str string) bool {
-	return globMatch(string(wp), str)
-}
-
 type wildcard struct {
 	selector selector.Selector
-	pattern  wildcardPattern
+	pattern  glob
 }
 
 func (n wildcard) Kind() string {
 	return KindLike
 }
 
 func Like(selector selector.Selector, pattern string) (Statement, error) {
-	parsedPattern, err := parseWildcardPattern(pattern)
+	g, err := parseGlob(pattern)
 	if err != nil {
 		return nil, err
 	}
 
-	return wildcard{selector: selector, pattern: parsedPattern}, nil
+	return wildcard{selector: selector, pattern: g}, nil
 }
 
 type quantifier struct {