Cache URI swarm name prefix.

To avoid having to build the whole name (which implies encoding the injector
public key) every time a URI swarm name is needed.

src/bep5_swarms.cpp

@@ -19,12 +19,17 @@ std::string compute_bridge_swarm_name(const ouinet::util::Ed25519PublicKey& pubk
         , "/bridges");
 }
 
-std::string compute_uri_swarm_name(const ouinet::util::Ed25519PublicKey& pubkey, unsigned protocol_version, boost::string_view key)
+std::string compute_uri_swarm_prefix(const ouinet::util::Ed25519PublicKey& pubkey, unsigned protocol_version)
 {
     return util::str
         ( "ed25519:", util::base32up_encode(pubkey.serialize())
         , "/v", protocol_version
-        , "/uri/", key);
+        , "/uri/");
+}
+
+std::string compute_uri_swarm_name(boost::string_view prefix, boost::string_view uri)
+{
+    return util::str(prefix, uri);
 }
 
 }} // namespaces

src/bep5_swarms.h

@@ -38,9 +38,13 @@ std::string compute_injector_swarm_name( const ouinet::util::Ed25519PublicKey&
 std::string compute_bridge_swarm_name( const ouinet::util::Ed25519PublicKey&
                                      , unsigned protocol_version);
 
-std::string compute_uri_swarm_name( const ouinet::util::Ed25519PublicKey&
-                                  , unsigned protocol_version
-                                  , boost::string_view key);
+// Reuse the resulting prefix with `compute_uri_swarm_name` below.
+std::string compute_uri_swarm_prefix( const ouinet::util::Ed25519PublicKey&
+                                    , unsigned protocol_version);
+
+// Reuse the prefix resulting from `compute_uri_swarm_prefix` above.
+std::string compute_uri_swarm_name( boost::string_view prefix
+                                  , boost::string_view uri);
 
 }} // namespaces
 

src/cache/bep5_http/client.cpp

@@ -36,6 +36,7 @@ struct Client::Impl {
 
     asio::executor ex;
     shared_ptr<bt::MainlineDht> dht;
+    string uri_swarm_prefix;
     util::Ed25519PublicKey cache_pk;
     fs::path cache_dir;
     unique_ptr<cache::AbstractHttpStore> http_store;
@@ -59,6 +60,8 @@ struct Client::Impl {
         , log_level_t log_level)
         : ex(dht_->get_executor())
         , dht(move(dht_))
+        , uri_swarm_prefix(bep5::compute_uri_swarm_prefix
+              (cache_pk, http_::protocol_version_current))
         , cache_pk(cache_pk)
         , cache_dir(move(cache_dir))
         , http_store(move(http_store))
@@ -70,8 +73,7 @@ struct Client::Impl {
 
     std::string compute_swarm_name(boost::string_view dht_group) const {
         return bep5::compute_uri_swarm_name(
-                cache_pk,
-                http_::protocol_version_current,
+                uri_swarm_prefix,
                 dht_group);
     }