cpp: Add revuid and adduid support

* lang/cpp/src/context.cpp
(Context::revUid, Context::startRevUid),
(Context::addUid, Context::startAddUid): New.
* lang/cpp/src/context.h: Declare new functions.
* lang/cpp/src/key.cpp (Key::UserID::revoke)
(Key::addUid): Idomatic helpers.
lang/cpp/src/key.h: Declare new functions.
* NEWS: Update accordingly.

NEWS

@@ -1,6 +1,17 @@
 Noteworthy changes in version 1.8.1 (unreleased)
 ------------------------------------------------
 
+ * cpp: Support for adduid and revuid operations.
+
+ * Interface changes relative to the 1.8.0 release:
+ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+ cpp: Context::revUid(const Key&, const char*)      NEW.
+ cpp: Context::startRevUid(const Key&, const char*) NEW.
+ cpp: Context::addUid(const Key&, const char*)      NEW.
+ cpp: Context::startAddUid(const Key&, const char*) NEW.
+ cpp: Key::UserID::revoke()                         NEW.
+ cpp: Key::addUid()                                 NEW.
+
 
 Noteworthy changes in version 1.8.0 (2016-11-16)
 ------------------------------------------------

lang/cpp/src/context.cpp

@@ -1376,6 +1376,30 @@ Error Context::setTofuPolicyStart(const Key &k, unsigned int policy)
                  k.impl(), to_tofu_policy_t(policy)));
 }
 
+Error Context::addUid(const Key &k, const char *userid)
+{
+    return Error(d->lasterr = gpgme_op_adduid(d->ctx,
+                 k.impl(), userid, 0));
+}
+
+Error Context::startAddUid(const Key &k, const char *userid)
+{
+    return Error(d->lasterr = gpgme_op_adduid_start(d->ctx,
+                 k.impl(), userid, 0));
+}
+
+Error Context::revUid(const Key &k, const char *userid)
+{
+    return Error(d->lasterr = gpgme_op_revuid(d->ctx,
+                 k.impl(), userid, 0));
+}
+
+Error Context::startRevUid(const Key &k, const char *userid)
+{
+    return Error(d->lasterr = gpgme_op_revuid_start(d->ctx,
+                 k.impl(), userid, 0));
+}
+
 // Engine Spawn stuff
 Error Context::spawn(const char *file, const char *argv[],
                      Data &input, Data &output, Data &err,

lang/cpp/src/context.h

@@ -214,6 +214,12 @@ public:
     GpgME::Error edit(const Key &key, std::unique_ptr<EditInteractor> function, Data &out);
     GpgME::Error startEditing(const Key &key, std::unique_ptr<EditInteractor> function, Data &out);
 
+    Error addUid(const Key &key, const char *userid);
+    Error startAddUid(const Key &key, const char *userid);
+
+    Error revUid(const Key &key, const char *userid);
+    Error startRevUid(const Key &key, const char *userid);
+
     // using TofuInfo::Policy
     Error setTofuPolicy(const Key &k, unsigned int policy);
     Error setTofuPolicyStart(const Key &k, unsigned int policy);

lang/cpp/src/key.cpp

@@ -906,6 +906,34 @@ std::string UserID::addrSpec() const
     return uid->address;
 }
 
+Error UserID::revoke()
+{
+    if (isNull()) {
+        return Error::fromCode(GPG_ERR_GENERAL);
+    }
+    auto ctx = Context::createForProtocol(parent().protocol());
+    if (!ctx) {
+        return Error::fromCode(GPG_ERR_INV_ENGINE);
+    }
+    Error ret = ctx->revUid(key, id());
+    delete ctx;
+    return ret;
+}
+
+Error Key::addUid(const char *uid)
+{
+    if (isNull()) {
+        return Error::fromCode(GPG_ERR_GENERAL);
+    }
+    auto ctx = Context::createForProtocol(protocol());
+    if (!ctx) {
+        return Error::fromCode(GPG_ERR_INV_ENGINE);
+    }
+    Error ret = ctx->addUid(key, uid);
+    delete ctx;
+    return ret;
+}
+
 std::ostream &operator<<(std::ostream &os, const UserID &uid)
 {
     os << "GpgME::UserID(";

lang/cpp/src/key.h

@@ -152,6 +152,17 @@ public:
      * how long the keylisting takes.*/
     void update();
 
+    /**
+     * @brief Add a user id to this key.
+     *
+     * Needs gnupg 2.1.13 and the key needs to be updated
+     * afterwards to see the new uid.
+     *
+     * @param uid should be fully formated and UTF-8 encoded.
+     *
+     * @returns a possible error.
+     **/
+    Error addUid(const char *uid);
 private:
     gpgme_key_t impl() const
     {
@@ -335,6 +346,13 @@ public:
      * @returns a normalized mail address for this userid
      * or an empty string. */
     std::string addrSpec() const;
+
+    /*! Revoke the user id.
+     *
+     * Key needs update afterwards.
+     *
+     * @returns an error on error.*/
+    Error revoke();
 private:
     shared_gpgme_key_t key;
     gpgme_user_id_t uid;