cpp: Add some convenience functions

* lang/cpp/src/context.cpp (Context::create): New.
* lang/cpp/src/context.h: Update accordingly.
* lang/cpp/src/key.cpp, lang/cpp/src/key.h:
(Key::isBad, Subkey::isBad, UserID::isBad)
(UserID::Signature::isBad): Add shorthand for the isX checks.
* NEWS: Mention it.

--
I don't know how often I wrote:
if (key.isNull() || key.isExpired() || key.isRevoked() ...

And for the context it is good practice to use a unique ptr
so the API should make it easy.

1 files changed, 20 insertions, 0 deletions

diff --git a/lang/cpp/src/key.cpp b/lang/cpp/src/key.cpp
index 8fc266ff..0d272926 100644
--- a/lang/cpp/src/key.cpp
+++ b/lang/cpp/src/key.cpp
@@ -1033,6 +1033,26 @@ time_t Key::lastUpdate() const
     return static_cast<time_t>(key ? key->last_update : 0);
 }
 
+bool Key::isBad() const
+{
+    return isNull() || isRevoked() || isExpired() || isDisabled() || isInvalid();
+}
+
+bool Subkey::isBad() const
+{
+    return isNull() || isRevoked() || isExpired() || isDisabled() || isInvalid();
+}
+
+bool UserID::isBad() const
+{
+    return isNull() || isRevoked() || isInvalid();
+}
+
+bool UserID::Signature::isBad() const
+{
+    return isNull() || isExpired() || isInvalid();
+}
+
 std::ostream &operator<<(std::ostream &os, const UserID &uid)
 {
     os << "GpgME::UserID(";