🌅 complete OS X keychain implementation.

Signed-off-by: David Calavera <david.calavera@gmail.com>

osxkeychain/osxkeychain_darwin.go

@@ -0,0 +1,125 @@
+package osxkeychain
+
+/*
+#cgo CFLAGS: -x objective-c
+#cgo LDFLAGS: -framework Security -framework Foundation
+
+#include "osxkeychain_darwin.h"
+#include <stdlib.h>
+*/
+import "C"
+import (
+	"errors"
+	"net/url"
+	"strconv"
+	"strings"
+	"unsafe"
+
+	"github.com/calavera/docker-credential-helpers/credentials"
+)
+
+type osxkeychain struct{}
+
+func New() credentials.Helper {
+	return osxkeychain{}
+}
+
+// Add adds new credentials to the keychain.
+func (h osxkeychain) Add(creds *credentials.Credentials) error {
+	s, err := splitServer(creds.ServerURL)
+	if err != nil {
+		return err
+	}
+	defer freeServer(s)
+
+	username := C.CString(creds.Username)
+	defer C.free(unsafe.Pointer(username))
+	password := C.CString(creds.Password)
+	defer C.free(unsafe.Pointer(password))
+
+	errMsg := C.keychain_add(s, username, password)
+	if errMsg != nil {
+		defer C.free(unsafe.Pointer(errMsg))
+		return errors.New(C.GoString(errMsg))
+	}
+
+	return nil
+}
+
+// Delete removes credentials from the keychain.
+func (h osxkeychain) Delete(serverURL string) error {
+	s, err := splitServer(serverURL)
+	if err != nil {
+		return err
+	}
+	defer freeServer(s)
+
+	errMsg := C.keychain_delete(s)
+	if errMsg != nil {
+		defer C.free(unsafe.Pointer(errMsg))
+		return errors.New(C.GoString(errMsg))
+	}
+
+	return nil
+}
+
+// Get returns the username and password to use for a given registry server URL.
+func (h osxkeychain) Get(serverURL string) (string, string, error) {
+	s, err := splitServer(serverURL)
+	if err != nil {
+		return "", "", err
+	}
+	defer freeServer(s)
+
+	var usernameLen C.uint
+	var username *C.char
+	var passwordLen C.uint
+	var password *C.char
+	defer C.free(unsafe.Pointer(username))
+	defer C.free(unsafe.Pointer(password))
+
+	errMsg := C.keychain_get(s, &usernameLen, &username, &passwordLen, &password)
+	if errMsg != nil {
+		defer C.free(unsafe.Pointer(errMsg))
+		return "", "", errors.New(C.GoString(errMsg))
+	}
+
+	user := C.GoStringN(username, C.int(usernameLen))
+	pass := C.GoStringN(password, C.int(passwordLen))
+	return user, pass, nil
+}
+
+func splitServer(serverURL string) (*C.struct_Server, error) {
+	u, err := url.Parse(serverURL)
+	if err != nil {
+		return nil, err
+	}
+
+	hostAndPort := strings.Split(u.Host, ":")
+	host := hostAndPort[0]
+	var port int
+	if len(hostAndPort) == 2 {
+		p, err := strconv.Atoi(hostAndPort[1])
+		if err != nil {
+			return nil, err
+		}
+		port = p
+	}
+
+	proto := C.kSecProtocolTypeHTTPS
+	if u.Scheme != "https" {
+		proto = C.kSecProtocolTypeHTTP
+	}
+
+	return &C.struct_Server{
+		proto: C.SecProtocolType(proto),
+		host:  C.CString(host),
+		port:  C.uint(port),
+		path:  C.CString(u.Path),
+	}, nil
+}
+
+func freeServer(s *C.struct_Server) {
+	C.free(unsafe.Pointer(s.host))
+	C.free(unsafe.Pointer(s.path))
+}