cpp: Add support for gpgme_op_setexpire

* lang/cpp/src/context.cpp
(Context::setExpire, Context::startSetExpire): New.
(Context::getLFSeparatedListOfFingerprintsFromSubkeys):
New helper.
* lang/cpp/src/context.h
(Context::SetExpireFlags): New enum.
(Context::setExpire, Context::startSetExpire): Add
prototypes.
(Context::getLFSeparatedListOfFingerprintsFromSubkeys):
Add as private helper.
--

GnuPG-bug-id: 5003

NEWS

@@ -4,10 +4,14 @@ Noteworthy changes in version 1.14.1 (unreleased)
 * New function gpgme_op_setexpire to make changing the expiration
   easier (requires GnuPG 2.1.22). [#4999]
 
+ * cpp: Support for set expire operations in the C++ bindings. [#5003]
+
  * Interface changes relative to the 1.14.0 release:
  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  gpgme_op_setexpire_start                   NEW.
  gpgme_op_setexpire                         NEW.
+ cpp: Context::setExpire                    NEW.
+ cpp: Context::startSetExpire               NEW.
 
 
 Noteworthy changes in version 1.14.0 (2020-07-16)

lang/cpp/src/context.cpp

@@ -51,6 +51,7 @@
 #include <gpgme.h>
 
 #include <istream>
+#include <numeric>
 #ifndef NDEBUG
 #include <iostream>
 using std::cerr;
@@ -1526,6 +1527,62 @@ Error Context::startCreateSubkey(const Key &k, const char *algo,
                  k.impl(), algo, reserved, expires, flags));
 }
 
+std::string Context::getLFSeparatedListOfFingerprintsFromSubkeys(const std::vector<Subkey> &subkeys)
+{
+    if (subkeys.empty()) {
+        return std::string();
+    }
+
+    std::vector<std::string> fprs;
+    fprs.reserve(subkeys.size());
+    for (auto &it : subkeys) {
+        if (it.fingerprint()) {
+            fprs.push_back(std::string(it.fingerprint()));
+        }
+    }
+
+    if (fprs.empty()) {
+        return std::string();
+    }
+
+    return std::accumulate(
+        std::next(fprs.begin()),
+        fprs.end(),
+        fprs[0],
+        [](const std::string &a, const std::string &b) {
+            return a + '\n' + b;
+        }
+    );
+}
+
+Error Context::setExpire(const Key &k, unsigned long expires,
+                         const std::vector<Subkey> &subkeys,
+                         const Context::SetExpireFlags flags)
+{
+    std::string subfprs;
+    if (flags & Context::SetExpireAllSubkeys) {
+        subfprs = "*";
+    } else {
+        subfprs = getLFSeparatedListOfFingerprintsFromSubkeys(subkeys);
+    }
+    return Error(d->lasterr = gpgme_op_setexpire(d->ctx,
+                 k.impl(), expires, subfprs.c_str(), 0));
+}
+
+Error Context::startSetExpire(const Key &k, unsigned long expires,
+                              const std::vector<Subkey> &subkeys,
+                              const Context::SetExpireFlags flags)
+{
+    std::string subfprs;
+    if (flags & Context::SetExpireAllSubkeys) {
+        subfprs = "*";
+    } else {
+        subfprs = getLFSeparatedListOfFingerprintsFromSubkeys(subkeys);
+    }
+    return Error(d->lasterr = gpgme_op_setexpire_start(d->ctx,
+                 k.impl(), expires, subfprs.c_str(), 0));
+}
+
 Error Context::setFlag(const char *name, const char *value)
 {
   return Error(d->lasterr = gpgme_set_ctx_flag(d->ctx, name, value));

lang/cpp/src/context.h

@@ -27,6 +27,7 @@
 #include "global.h"
 
 #include "error.h"
+#include "key.h"
 #include "verificationresult.h" // for Signature::Notation
 
 #include <memory>
@@ -37,7 +38,6 @@
 namespace GpgME
 {
 
-class Key;
 class Data;
 class TrustItem;
 class ProgressProvider;
@@ -273,6 +273,18 @@ public:
                             unsigned long expires = 0,
                             unsigned int flags = 0);
 
+    enum SetExpireFlags {
+        SetExpireDefault = 0,
+        SetExpireAllSubkeys = 1
+    };
+
+    Error setExpire(const Key &k, unsigned long expires,
+                    const std::vector<Subkey> &subkeys = std::vector<Subkey>(),
+                    const SetExpireFlags flags = SetExpireDefault);
+    Error startSetExpire(const Key &k, unsigned long expires,
+                         const std::vector<Subkey> &subkeys = std::vector<Subkey>(),
+                         const SetExpireFlags flags = SetExpireDefault);
+
     // using TofuInfo::Policy
     Error setTofuPolicy(const Key &k, unsigned int policy);
     Error setTofuPolicyStart(const Key &k, unsigned int policy);
@@ -488,6 +500,8 @@ private:
     // on the "Friendlyness" of context to access the gpgme types.
     gpgme_key_t *getKeysFromRecipients(const std::vector<Key> &recipients);
 
+    std::string getLFSeparatedListOfFingerprintsFromSubkeys(const std::vector<Subkey> &subkeys);
+
 private:
     Private *const d;