remove ListOfMatchable (#286)

Author: sukunrt

util.go

@@ -123,16 +123,7 @@ func ForEach(m Multiaddr, cb func(c Component) bool) {
 	}
 }
 
-type componentList []Component
-
-func (m componentList) Get(i int) meg.Matchable {
-	return &m[i]
-}
-
-func (m componentList) Len() int {
-	return len(m)
-}
 func (m Multiaddr) Match(p ...meg.Pattern) (bool, error) {
 	matcher := meg.PatternToMatcher(p...)
-	return meg.Match(matcher, componentList(m))
+	return meg.Match(matcher, m)
 }

x/meg/bench_test.go

@@ -29,18 +29,8 @@ func preallocateCapture() *preallocatedCapture {
 
 var webrtcMatchPrealloc *preallocatedCapture
 
-type componentList []multiaddr.Component
-
-func (m componentList) Get(i int) meg.Matchable {
-	return &m[i]
-}
-
-func (m componentList) Len() int {
-	return len(m)
-}
-
 func (p *preallocatedCapture) IsWebRTCDirectMultiaddr(addr multiaddr.Multiaddr) (bool, int) {
-	found, _ := meg.Match(p.matcher, componentList(addr))
+	found, _ := meg.Match(p.matcher, addr)
 	return found, len(p.certHashes)
 }
 
@@ -117,7 +107,7 @@ func isWebTransportMultiaddrPrealloc() *preallocatedCapture {
 
 func IsWebTransportMultiaddrPrealloc(m multiaddr.Multiaddr) (bool, int) {
 	p := isWebTransportMultiaddrPrealloc()
-	found, _ := meg.Match(p.matcher, componentList(m))
+	found, _ := meg.Match(p.matcher, m)
 	return found, len(p.certHashes)
 }
 
@@ -375,7 +365,7 @@ func BenchmarkIsWebTransportMultiaddrNoCapturePrealloc(b *testing.B) {
 
 	b.ResetTimer()
 	for i := 0; i < b.N; i++ {
-		isWT, _ := meg.Match(wtPreallocNoCapture, componentList(addr))
+		isWT, _ := meg.Match(wtPreallocNoCapture, addr)
 		if !isWT {
 			b.Fatal("unexpected result")
 		}

x/meg/meg.go

@@ -67,25 +67,16 @@ type Matchable interface {
 	Bytes() []byte
 }
 
-// ListOfMatchable is anything list-like that contains Matchable items.
-// This allows us to convert a slice of []T as a []Matchable when *T implements
-// Matchable. In the future, this may not be required if Go generics allows us
-// to say S ~[]T, and *T implements Matchable. This may also not be required if
-// we move this out of its own package and depend on Multiaddr and Components
-// directly.
-type ListOfMatchable interface {
-	Get(i int) Matchable
-	Len() int
-}
-
 // Match returns whether the given Components match the Matcher
 //
 // Errors are used to communicate capture errors.
 // If the error is non-nil the returned bool will be false.
 //
-// Components must be a ListOfMatchable to allow us to use a slice of []T as a
-// []Matchable when *T implements Matchable.
-func Match[L ListOfMatchable](matcher Matcher, components L) (bool, error) {
+// The PT pattern is from: https://go.dev/blog/generic-interfaces
+func Match[T any, PT interface {
+	*T
+	Matchable
+}](matcher Matcher, components []T) (bool, error) {
 	states := matcher.states
 	startStateIdx := matcher.startIdx
 
@@ -108,14 +99,14 @@ func Match[L ListOfMatchable](matcher Matcher, components L) (bool, error) {
 
 	currentStates = appendState(currentStates, states, startStateIdx, nil, visitedBitSet)
 
-	for ic := range components.Len() {
+	for ic := range len(components) {
 		clear(visitedBitSet)
 		if len(currentStates.states) == 0 {
 			return false, nil
 		}
 		for i, stateIndex := range currentStates.states {
 			s := &states[stateIndex]
-			cPtr := components.Get(ic)
+			cPtr := PT(&components[ic])
 			if s.codeOrKind == matchAny || (s.codeOrKind >= 0 && s.codeOrKind == cPtr.Code()) {
 				cm := currentStates.captures[i]
 				if s.capture != nil {

x/meg/meg_test.go

@@ -226,7 +226,7 @@ func TestCapture(t *testing.T) {
 	_ = testCases
 	for _, tc := range testCases {
 		state, assert := tc.setup()
-		if matches, _ := Match(state, codeAndValueList(tc.parts)); !matches {
+		if matches, _ := Match(state, tc.parts); !matches {
 			t.Fatalf("failed to match %v with %v", tc.parts, state)
 		}
 		assert()
@@ -235,7 +235,7 @@ func TestCapture(t *testing.T) {
 
 func TestPreferExactOverAny(t *testing.T) {
 	t.Run("Optional", func(t *testing.T) {
-		m := codeAndValueList{
+		m := []codeAndValue{
 			{0, "hello"},
 			{1, "foo"},
 			{42, "A"},
@@ -260,7 +260,7 @@ func TestPreferExactOverAny(t *testing.T) {
 	})
 
 	t.Run("Or", func(t *testing.T) {
-		m := codeAndValueList{
+		m := []codeAndValue{
 			{1, "foo"},
 			{42, "A"},
 			{42, "B"},
@@ -282,7 +282,7 @@ func TestPreferExactOverAny(t *testing.T) {
 		}
 	})
 	t.Run("OneOrMore", func(t *testing.T) {
-		m := codeAndValueList{
+		m := []codeAndValue{
 			{1, "foo"},
 			{42, "A"},
 			{42, "B"},
@@ -305,7 +305,7 @@ func TestPreferExactOverAny(t *testing.T) {
 }
 
 func TestCaptureWithAny(t *testing.T) {
-	m := codeAndValueList{
+	m := []codeAndValue{
 		{0, "hello"},
 		{1, "foo"},
 		{42, "A"},
@@ -334,25 +334,15 @@ func TestCaptureWithAny(t *testing.T) {
 	}
 }
 
-type codeAndValueList []codeAndValue
-
-func (c codeAndValueList) Get(i int) Matchable {
-	return &c[i]
-}
-
-func (c codeAndValueList) Len() int {
-	return len(c)
-}
-
-func codesToCodeAndValue(codes []int) codeAndValueList {
+func codesToCodeAndValue(codes []int) []codeAndValue {
 	out := make([]codeAndValue, len(codes))
 	for i, c := range codes {
 		out[i] = codeAndValue{code: c}
 	}
 	return out
 }
 
-func bytesToCodeAndValue(codes []byte) codeAndValueList {
+func bytesToCodeAndValue(codes []byte) []codeAndValue {
 	out := make([]codeAndValue, len(codes))
 	for i, c := range codes {
 		out[i] = codeAndValue{code: int(c)}