// Copyright 2022 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package tls
import (
"crypto/x509"
"runtime"
"sync"
"weak"
)
// weakCertCache provides a cache of *x509.Certificates, allowing multiple
// connections to reuse parsed certificates, instead of re-parsing the
// certificate for every connection, which is an expensive operation.
type weakCertCache struct{ sync.Map }
func (wcc *weakCertCache) newCert(der []byte) (*x509.Certificate, error) {
if entry, ok := wcc.Load(string(der)); ok {
if v := entry.(weak.Pointer[x509.Certificate]).Value(); v != nil {
return v, nil
}
}
cert, err := x509.ParseCertificate(der)
if err != nil {
return nil, err
}
wp := weak.Make(cert)
if entry, loaded := wcc.LoadOrStore(string(der), wp); !loaded {
runtime.AddCleanup(cert, func(_ any) { wcc.CompareAndDelete(string(der), entry) }, any(string(der)))
} else if v := entry.(weak.Pointer[x509.Certificate]).Value(); v != nil {
return v, nil
} else {
if wcc.CompareAndSwap(string(der), entry, wp) {
runtime.AddCleanup(cert, func(_ any) { wcc.CompareAndDelete(string(der), wp) }, any(string(der)))
}
}
return cert, nil
}
var globalCertCache = new(weakCertCache)
