1 files changed, 53 insertions, 0 deletions
diff --git a/identity/common.go b/identity/common.go
new file mode 100644
index 00000000..32dd3d9e
--- /dev/null
+++ b/identity/common.go
@@ -0,0 +1,53 @@
+package identity
+
+import (
+	"encoding/json"
+	"errors"
+	"fmt"
+	"strings"
+)
+
+var ErrIdentityNotExist = errors.New("identity doesn't exist")
+
+type ErrMultipleMatch struct {
+	Matching []string
+}
+
+func (e ErrMultipleMatch) Error() string {
+	return fmt.Sprintf("Multiple matching identities found:\n%s", strings.Join(e.Matching, "\n"))
+}
+
+// Custom unmarshaling function to allow package user to delegate
+// the decoding of an Identity and distinguish between an Identity
+// and a Bare.
+//
+// If the given message has a "id" field, it's considered being a proper Identity.
+func UnmarshalJSON(raw json.RawMessage) (Interface, error) {
+	// First try to decode as a normal Identity
+	var i Identity
+
+	err := json.Unmarshal(raw, &i)
+	if err == nil && i.id != "" {
+		return &i, nil
+	}
+
+	// abort if we have an error other than the wrong type
+	if _, ok := err.(*json.UnmarshalTypeError); err != nil && !ok {
+		return nil, err
+	}
+
+	// Fallback on a legacy Bare identity
+	var b Bare
+
+	err = json.Unmarshal(raw, &b)
+	if err == nil && (b.name != "" || b.login != "") {
+		return &b, nil
+	}
+
+	// abort if we have an error other than the wrong type
+	if _, ok := err.(*json.UnmarshalTypeError); err != nil && !ok {
+		return nil, err
+	}
+
+	return nil, fmt.Errorf("unknown identity type")
+}