ffi: Wrap tpk::UserIDBinding.

  - Add sq_user_id_binding_user_id to return the value of the UserID
    from a UserIDBinding.

  - Export an interface to iterate over UserIDBindings,
    sq_tpk_user_id_binding_iter, fn sq_user_id_binding_iter_free,
    sq_user_id_binding_iter_next.

1 files changed, 37 insertions, 0 deletions

diff --git a/ffi/include/sequoia/openpgp.h b/ffi/include/sequoia/openpgp.h
index f898c2a3..c39581c7 100644
--- a/ffi/include/sequoia/openpgp.h
+++ b/ffi/include/sequoia/openpgp.h
@@ -545,6 +545,38 @@ typedef enum sq_reason_for_revocation {
   SQ_REASON_FOR_REVOCATION_FORCE_WIDTH = INT_MAX,
 } sq_reason_for_revocation_t;
 
+/* openpgp::tpk::UserIDBinding.  */
+
+/*/
+/// A `UserIDBinding`.
+/*/
+typedef struct sq_user_id_binding *sq_user_id_binding_t;
+
+/*/
+/// Returns the user id.
+///
+/// This function may fail and return NULL if the user id contains an
+/// interior NUL byte.  We do this rather than complicate the API, as
+/// there is no valid use for such user ids; they must be malicious.
+///
+/// The caller must free the returned value.
+/*/
+char *sq_user_id_binding_user_id (sq_user_id_binding_t binding);
+
+/* openpgp::tpk::UserIDBindingIter.  */
+
+/*/
+/// An iterator over `UserIDBinding`s.
+/*/
+typedef struct sq_user_id_binding_iter *sq_user_id_binding_iter_t;
+
+/*/
+/// Returns the next element in the iterator.
+/*/
+sq_user_id_binding_t sq_user_id_binding_iter_next (sq_user_id_binding_iter_t iter);
+
+/// Frees an sq_user_id_binding_iter_t.
+void sq_user_id_binding_iter_free (sq_user_id_binding_iter_t iter);
 
 /* openpgp::tpk.  */
 
@@ -708,6 +740,11 @@ sq_tpk_t sq_tpk_set_expiry(sq_context_t ctx,
 /*/
 int sq_tpk_is_tsk(sq_tpk_t tpk);
 
+/*/
+/// Returns an iterator over the `UserIDBinding`s.
+/*/
+sq_user_id_binding_iter_t sq_tpk_user_id_binding_iter (sq_tpk_t tpk);
+
 /* TPKBuilder */
 
 typedef struct sq_tpk_builder *sq_tpk_builder_t;