Get ride of functor passing for transaction signing

Just embed the logic needed right in to wallet implementations. This will cause a little bit of code duplication but avoids the complexity of the functor

libraries/chain/include/eosio/chain/transaction.hpp

@@ -76,8 +76,6 @@ namespace eosio { namespace chain {
 
    struct signed_transaction : public transaction
    {
-      using sign_digest_functor = std::function<signature_type(digest_type)>;
-
       signed_transaction() = default;
 //      signed_transaction( const signed_transaction& ) = default;
 //      signed_transaction( signed_transaction&& ) = default;
@@ -92,7 +90,6 @@ namespace eosio { namespace chain {
       vector<bytes>             context_free_data; ///< for each context-free action, there is an entry here
 
       const signature_type&     sign(const private_key_type& key, const chain_id_type& chain_id);
-      const signature_type&     sign(sign_digest_functor signature_request, const chain_id_type& chain_id);
       signature_type            sign(const private_key_type& key, const chain_id_type& chain_id)const;
       flat_set<public_key_type> get_signature_keys( const chain_id_type& chain_id, bool allow_duplicate_keys = false )const;
    };

libraries/chain/transaction.cpp

@@ -119,11 +119,6 @@ const signature_type& signed_transaction::sign(const private_key_type& key, cons
    return signatures.back();
 }
 
-const signature_type& signed_transaction::sign(sign_digest_functor signature_request, const chain_id_type& chain_id) {
-   signatures.push_back(signature_request(sig_digest(chain_id, context_free_data)));
-   return signatures.back();
-}
-
 signature_type signed_transaction::sign(const private_key_type& key, const chain_id_type& chain_id)const {
    return key.sign(sig_digest(chain_id, context_free_data));
 }

plugins/wallet_plugin/include/eosio/wallet_plugin/wallet.hpp

@@ -171,9 +171,9 @@ class soft_wallet final : public wallet_api
        */
       string create_key( string key_type ) override;
 
-      /* Returns a fuctor to sign a digest via the given public_key
+      /* Attempts to sign a digest via the given public_key
       */
-      optional<signed_transaction::sign_digest_functor> sign_digest( public_key_type public_key ) override;
+      optional<signature_type> try_sign_digest( const digest_type digest, const public_key_type public_key ) override;
 
       std::shared_ptr<detail::soft_wallet_impl> my;
       void encrypt_keys();

plugins/wallet_plugin/include/eosio/wallet_plugin/wallet_api.hpp

@@ -91,12 +91,9 @@ class wallet_api
        */
       virtual string create_key( string key_type ) = 0;
 
-      /** Returns a functor that can be used to sign a digest based on the given public key (provided the
-       *
-       * wallet can sign with that key)
-       * @param public_key the key type to create. May be empty to allow wallet to pick appropriate/"best" key type
+      /** Returns a signature given the digest and public_key, if this wallet can sign via that public key
        */
-      virtual optional<signed_transaction::sign_digest_functor> sign_digest( public_key_type public_key ) = 0;
+      virtual optional<signature_type> try_sign_digest( const digest_type digest, const public_key_type public_key ) = 0;
 };
 
 }}
\ No newline at end of file

plugins/wallet_plugin/wallet.cpp

@@ -128,13 +128,11 @@ public:
       return optional<private_key_type>();
    }
 
-   optional<signed_transaction::sign_digest_functor> sign_digest( public_key_type public_key ) {
+   optional<signature_type> try_sign_digest( const digest_type digest, const public_key_type public_key ) {
       auto it = _keys.find(public_key);
       if( it == _keys.end() )
-         return optional<signed_transaction::sign_digest_functor>{};
-      return [priv_key = it->second](digest_type d) {
-         return priv_key.sign(d);
-      };
+         return optional<signature_type>{};
+      return it->second.sign(digest);
    }
 
    private_key_type get_private_key(const public_key_type& id)const
@@ -377,8 +375,8 @@ private_key_type soft_wallet::get_private_key( public_key_type pubkey )const
    return my->get_private_key( pubkey );
 }
 
-optional<signed_transaction::sign_digest_functor> soft_wallet::sign_digest( public_key_type public_key ) {
-   return my->sign_digest(public_key);
+optional<signature_type> soft_wallet::try_sign_digest( const digest_type digest, const public_key_type public_key ) {
+   return my->try_sign_digest(digest, public_key);
 }
 
 pair<public_key_type,private_key_type> soft_wallet::get_private_key_from_password( string account, string role, string password )const {

plugins/wallet_plugin/wallet_manager.cpp

@@ -204,9 +204,9 @@ wallet_manager::sign_transaction(const chain::signed_transaction& txn, const fla
       bool found = false;
       for (const auto& i : wallets) {
          if (!i.second->is_locked()) {
-            auto f = i.second->sign_digest(pk);
-            if (f) {
-               stxn.sign(*f, id);
+            optional<signature_type> sig = i.second->try_sign_digest(stxn.sig_digest(id, stxn.context_free_data), pk);
+            if (sig) {
+               stxn.signatures.push_back(*sig);
                found = true;
                break; // inner for
             }
@@ -227,10 +227,9 @@ wallet_manager::sign_digest(const chain::digest_type& digest, const public_key_t
    try {
       for (const auto& i : wallets) {
          if (!i.second->is_locked()) {
-            auto f = i.second->sign_digest(key);
-            if (f) {
-               return (*f)(digest);
-            }
+            optional<signature_type> sig = i.second->try_sign_digest(digest, key);
+            if (sig)
+               return *sig;
          }
       }
    } FC_LOG_AND_RETHROW();