Cleanup: Avoid parameter copying overhead

42 files changed, 183 insertions, 172 deletions

diff --git a/src/server/BlockImpl.cpp b/src/server/BlockImpl.cpp
index 263e6fce..abea85eb 100644
--- a/src/server/BlockImpl.cpp
+++ b/src/server/BlockImpl.cpp
@@ -294,10 +294,10 @@ BlockImpl::post_process(RunContext& context)
 }
 
 void
-BlockImpl::set_port_buffer(uint32_t    voice,
-                           uint32_t    port_num,
-                           BufferRef   buf,
-                           SampleCount offset)
+BlockImpl::set_port_buffer(uint32_t         voice,
+                           uint32_t         port_num,
+                           const BufferRef& buf,
+                           SampleCount      offset)
 {
 	/*std::cout << path() << " set port " << port_num << " voice " << voice
 	  << " buffer " << buf << " offset " << offset << std::endl;*/
diff --git a/src/server/BlockImpl.hpp b/src/server/BlockImpl.hpp
index c8c36ddf..15a4e075 100644
--- a/src/server/BlockImpl.hpp
+++ b/src/server/BlockImpl.hpp
@@ -133,10 +133,10 @@ public:
 	virtual void post_process(RunContext& context);
 
 	/** Set the buffer of a port to a given buffer (e.g. connect plugin to buffer) */
-	virtual void set_port_buffer(uint32_t    voice,
-	                             uint32_t    port_num,
-	                             BufferRef   buf,
-	                             SampleCount offset);
+	virtual void set_port_buffer(uint32_t         voice,
+	                             uint32_t         port_num,
+	                             const BufferRef& buf,
+	                             SampleCount      offset);
 
 	Node*             port(uint32_t index)      const override;
 	virtual PortImpl* port_impl(uint32_t index) const { return (*_ports)[index]; }
diff --git a/src/server/Broadcaster.cpp b/src/server/Broadcaster.cpp
index c3fb82ef..914b891b 100644
--- a/src/server/Broadcaster.cpp
+++ b/src/server/Broadcaster.cpp
@@ -42,7 +42,7 @@ Broadcaster::~Broadcaster()
 /** Register a client to receive messages over the notification band.
  */
 void
-Broadcaster::register_client(SPtr<Interface> client)
+Broadcaster::register_client(const SPtr<Interface>& client)
 {
 	std::lock_guard<std::mutex> lock(_clients_mutex);
 	_clients.insert(client);
@@ -53,7 +53,7 @@ Broadcaster::register_client(SPtr<Interface> client)
  * @return true if client was found and removed.
  */
 bool
-Broadcaster::unregister_client(SPtr<Interface> client)
+Broadcaster::unregister_client(const SPtr<Interface>& client)
 {
 	std::lock_guard<std::mutex> lock(_clients_mutex);
 	const size_t erased = _clients.erase(client);
@@ -62,7 +62,7 @@ Broadcaster::unregister_client(SPtr<Interface> client)
 }
 
 void
-Broadcaster::set_broadcast(SPtr<Interface> client, bool broadcast)
+Broadcaster::set_broadcast(const SPtr<Interface>& client, bool broadcast)
 {
 	if (broadcast) {
 		_broadcastees.insert(client);
diff --git a/src/server/Broadcaster.hpp b/src/server/Broadcaster.hpp
index a2d75284..bf586c38 100644
--- a/src/server/Broadcaster.hpp
+++ b/src/server/Broadcaster.hpp
@@ -45,18 +45,22 @@ public:
 	Broadcaster();
 	~Broadcaster();
 
-	void register_client(SPtr<Interface> client);
-	bool unregister_client(SPtr<Interface> client);
+	void register_client(const SPtr<Interface>& client);
+	bool unregister_client(const SPtr<Interface>& client);
 
-	void set_broadcast(SPtr<Interface> client, bool broadcast);
+	void set_broadcast(const SPtr<Interface>& client, bool broadcast);
 
 	/** Ignore a client when broadcasting.
 	 *
 	 * This is used to prevent feeding back updates to the client that
 	 * initiated a property set in the first place.
 	 */
-	void set_ignore_client(SPtr<Interface> client) { _ignore_client = client; }
-	void clear_ignore_client()                     { _ignore_client.reset(); }
+	void set_ignore_client(const SPtr<Interface>& client)
+	{
+		_ignore_client = client;
+	}
+
+	void clear_ignore_client() { _ignore_client.reset(); }
 
 	/** Return true iff there are any clients with broadcasting enabled.
 	 *
diff --git a/src/server/Engine.cpp b/src/server/Engine.cpp
index 18feff1f..545ce72b 100644
--- a/src/server/Engine.cpp
+++ b/src/server/Engine.cpp
@@ -336,7 +336,7 @@ Engine::main_iteration()
 }
 
 void
-Engine::set_driver(SPtr<Driver> driver)
+Engine::set_driver(const SPtr<Driver>& driver)
 {
 	_driver = driver;
 	for (const auto& ctx : _run_contexts) {
@@ -510,14 +510,14 @@ Engine::log() const
 }
 
 void
-Engine::register_client(SPtr<Interface> client)
+Engine::register_client(const SPtr<Interface>& client)
 {
 	log().info("Registering client <%1%>\n", client->uri().c_str());
 	_broadcaster->register_client(client);
 }
 
 bool
-Engine::unregister_client(SPtr<Interface> client)
+Engine::unregister_client(const SPtr<Interface>& client)
 {
 	log().info("Unregistering client <%1%>\n", client->uri().c_str());
 	return _broadcaster->unregister_client(client);
diff --git a/src/server/Engine.hpp b/src/server/Engine.hpp
index d1f2da3d..55099f45 100644
--- a/src/server/Engine.hpp
+++ b/src/server/Engine.hpp
@@ -93,15 +93,15 @@ public:
 	unsigned run(uint32_t sample_count) override;
 	void quit() override;
 	bool main_iteration() override;
-	void register_client(SPtr<Interface> client) override;
-	bool unregister_client(SPtr<Interface> client) override;
+	void register_client(const SPtr<Interface>& client) override;
+	bool unregister_client(const SPtr<Interface>& client) override;
 
 	void listen() override;
 
 	/** Return a random [0..1] float with uniform distribution */
 	float frand() { return _uniform_dist(_rand_engine); }
 
-	void set_driver(SPtr<Driver> driver);
+	void set_driver(const SPtr<Driver>& driver);
 
 	/** Return the frame time to execute an event that arrived now.
 	 *
diff --git a/src/server/Event.hpp b/src/server/Event.hpp
index 1bd61187..7da4b955 100644
--- a/src/server/Event.hpp
+++ b/src/server/Event.hpp
@@ -104,7 +104,10 @@ public:
 	inline Engine& engine() { return _engine; }
 
 protected:
-	Event(Engine& engine, SPtr<Interface> client, int32_t id, FrameTime time)
+	Event(Engine&                engine,
+	      const SPtr<Interface>& client,
+	      int32_t                id,
+	      FrameTime              time)
 		: _engine(engine)
 		, _next(nullptr)
 		, _request_client(std::move(client))
diff --git a/src/server/GraphImpl.cpp b/src/server/GraphImpl.cpp
index c00819c2..db1b4561 100644
--- a/src/server/GraphImpl.cpp
+++ b/src/server/GraphImpl.cpp
@@ -271,7 +271,7 @@ GraphImpl::remove_block(BlockImpl& block)
 }
 
 void
-GraphImpl::add_arc(SPtr<ArcImpl> a)
+GraphImpl::add_arc(const SPtr<ArcImpl>& a)
 {
 	ThreadManager::assert_thread(THREAD_PRE_PROCESS);
 	_arcs.emplace(std::make_pair(a->tail(), a->head()), a);
diff --git a/src/server/GraphImpl.hpp b/src/server/GraphImpl.hpp
index 846996f3..a03d3faa 100644
--- a/src/server/GraphImpl.hpp
+++ b/src/server/GraphImpl.hpp
@@ -156,7 +156,7 @@ public:
 	/** Add an arc to this graph.
 	 * Pre-processing thread only.
 	 */
-	void add_arc(SPtr<ArcImpl> a);
+	void add_arc(const SPtr<ArcImpl>& a);
 
 	/** Remove an arc from this graph.
 	 * Pre-processing thread only.
diff --git a/src/server/LV2Block.cpp b/src/server/LV2Block.cpp
index aa9339d1..d7406bb5 100644
--- a/src/server/LV2Block.cpp
+++ b/src/server/LV2Block.cpp
@@ -732,10 +732,10 @@ LV2Block::save_preset(const URI&        uri,
 }
 
 void
-LV2Block::set_port_buffer(uint32_t    voice,
-                          uint32_t    port_num,
-                          BufferRef   buf,
-                          SampleCount offset)
+LV2Block::set_port_buffer(uint32_t         voice,
+                          uint32_t         port_num,
+                          const BufferRef& buf,
+                          SampleCount      offset)
 {
 	BlockImpl::set_port_buffer(voice, port_num, buf, offset);
 	lilv_instance_connect_port(
diff --git a/src/server/LV2Block.hpp b/src/server/LV2Block.hpp
index 07c04321..8046189e 100644
--- a/src/server/LV2Block.hpp
+++ b/src/server/LV2Block.hpp
@@ -85,10 +85,10 @@ public:
 	boost::optional<Resource> save_preset(const URI&        uri,
 	                                      const Properties& props) override;
 
-	void set_port_buffer(uint32_t    voice,
-	                     uint32_t    port_num,
-	                     BufferRef   buf,
-	                     SampleCount offset) override;
+	void set_port_buffer(uint32_t         voice,
+	                     uint32_t         port_num,
+	                     const BufferRef& buf,
+	                     SampleCount      offset) override;
 
 	static LilvState* load_state(World& world, const FilePath& path);
 
diff --git a/src/server/Task.cpp b/src/server/Task.cpp
index 0d76a43f..48da6040 100644
--- a/src/server/Task.cpp
+++ b/src/server/Task.cpp
@@ -140,7 +140,9 @@ Task::simplify(std::unique_ptr<Task>&& task)
 }
 
 void
-Task::dump(std::function<void (const std::string&)> sink, unsigned indent, bool first) const
+Task::dump(const std::function<void(const std::string&)>& sink,
+           unsigned                                       indent,
+           bool                                           first) const
 {
 	if (!first) {
 		sink("\n");
diff --git a/src/server/Task.hpp b/src/server/Task.hpp
index a6489e61..e8b658c3 100644
--- a/src/server/Task.hpp
+++ b/src/server/Task.hpp
@@ -73,7 +73,9 @@ public:
 	void run(RunContext& context);
 
 	/** Pretty print task to the given stream (recursively). */
-	void dump(std::function<void (const std::string&)> sink, unsigned indent, bool first) const;
+	void dump(const std::function<void(const std::string&)>& sink,
+	          unsigned                                       indent,
+	          bool                                           first) const;
 
 	/** Return true iff this is an empty task. */
 	bool empty() const { return _mode != Mode::SINGLE && _children.empty(); }
diff --git a/src/server/events/Connect.cpp b/src/server/events/Connect.cpp
index d27e1e3b..23a7d4b4 100644
--- a/src/server/events/Connect.cpp
+++ b/src/server/events/Connect.cpp
@@ -38,10 +38,10 @@ namespace ingen {
 namespace server {
 namespace events {
 
-Connect::Connect(Engine&               engine,
-                 SPtr<Interface>       client,
-                 SampleCount           timestamp,
-                 const ingen::Connect& msg)
+Connect::Connect(Engine&                engine,
+                 const SPtr<Interface>& client,
+                 SampleCount            timestamp,
+                 const ingen::Connect&  msg)
 	: Event(engine, client, msg.seq, timestamp)
 	, _msg(msg)
 	, _graph(nullptr)
diff --git a/src/server/events/Connect.hpp b/src/server/events/Connect.hpp
index 625fa39d..adc80afc 100644
--- a/src/server/events/Connect.hpp
+++ b/src/server/events/Connect.hpp
@@ -38,10 +38,10 @@ namespace events {
 class Connect : public Event
 {
 public:
-	Connect(Engine&               engine,
-	        SPtr<Interface>       client,
-	        SampleCount           timestamp,
-	        const ingen::Connect& msg);
+	Connect(Engine&                engine,
+	        const SPtr<Interface>& client,
+	        SampleCount            timestamp,
+	        const ingen::Connect&  msg);
 
 	bool pre_process(PreProcessContext& ctx) override;
 	void execute(RunContext& context) override;
diff --git a/src/server/events/Copy.cpp b/src/server/events/Copy.cpp
index 38cbc6d8..a8e08924 100644
--- a/src/server/events/Copy.cpp
+++ b/src/server/events/Copy.cpp
@@ -36,10 +36,10 @@ namespace ingen {
 namespace server {
 namespace events {
 
-Copy::Copy(Engine&            engine,
-           SPtr<Interface>    client,
-           SampleCount        timestamp,
-           const ingen::Copy& msg)
+Copy::Copy(Engine&                engine,
+           const SPtr<Interface>& client,
+           SampleCount            timestamp,
+           const ingen::Copy&     msg)
 	: Event(engine, client, msg.seq, timestamp)
 	, _msg(msg)
 	, _old_block(nullptr)
diff --git a/src/server/events/Copy.hpp b/src/server/events/Copy.hpp
index 86a95e9c..26673a55 100644
--- a/src/server/events/Copy.hpp
+++ b/src/server/events/Copy.hpp
@@ -35,10 +35,10 @@ namespace events {
 class Copy : public Event
 {
 public:
-	Copy(Engine&            engine,
-	     SPtr<Interface>    client,
-	     SampleCount        timestamp,
-	     const ingen::Copy& msg);
+	Copy(Engine&                engine,
+	     const SPtr<Interface>& client,
+	     SampleCount            timestamp,
+	     const ingen::Copy&     msg);
 
 	bool pre_process(PreProcessContext& ctx) override;
 	void execute(RunContext& context) override;
diff --git a/src/server/events/CreateBlock.cpp b/src/server/events/CreateBlock.cpp
index cfeb0e3d..e8816954 100644
--- a/src/server/events/CreateBlock.cpp
+++ b/src/server/events/CreateBlock.cpp
@@ -38,12 +38,12 @@ namespace ingen {
 namespace server {
 namespace events {
 
-CreateBlock::CreateBlock(Engine&           engine,
-                         SPtr<Interface>   client,
-                         int32_t           id,
-                         SampleCount       timestamp,
-                         const Raul::Path& path,
-                         Properties&       properties)
+CreateBlock::CreateBlock(Engine&                engine,
+                         const SPtr<Interface>& client,
+                         int32_t                id,
+                         SampleCount            timestamp,
+                         const Raul::Path&      path,
+                         Properties&            properties)
 	: Event(engine, client, id, timestamp)
 	, _path(path)
 	, _properties(properties)
diff --git a/src/server/events/CreateBlock.hpp b/src/server/events/CreateBlock.hpp
index bf34f6e2..00f58008 100644
--- a/src/server/events/CreateBlock.hpp
+++ b/src/server/events/CreateBlock.hpp
@@ -38,12 +38,12 @@ namespace events {
 class CreateBlock : public Event
 {
 public:
-	CreateBlock(Engine&           engine,
-	            SPtr<Interface>   client,
-	            int32_t           id,
-	            SampleCount       timestamp,
-	            const Raul::Path& path,
-	            Properties&       properties);
+	CreateBlock(Engine&                engine,
+	            const SPtr<Interface>& client,
+	            int32_t                id,
+	            SampleCount            timestamp,
+	            const Raul::Path&      path,
+	            Properties&            properties);
 
 	bool pre_process(PreProcessContext& ctx) override;
 	void execute(RunContext& context) override;
diff --git a/src/server/events/CreateGraph.cpp b/src/server/events/CreateGraph.cpp
index 5561d147..3e847bdd 100644
--- a/src/server/events/CreateGraph.cpp
+++ b/src/server/events/CreateGraph.cpp
@@ -35,12 +35,12 @@ namespace ingen {
 namespace server {
 namespace events {
 
-CreateGraph::CreateGraph(Engine&           engine,
-                         SPtr<Interface>   client,
-                         int32_t           id,
-                         SampleCount       timestamp,
-                         const Raul::Path& path,
-                         const Properties& properties)
+CreateGraph::CreateGraph(Engine&                engine,
+                         const SPtr<Interface>& client,
+                         int32_t                id,
+                         SampleCount            timestamp,
+                         const Raul::Path&      path,
+                         const Properties&      properties)
 	: Event(engine, client, id, timestamp)
 	, _path(path)
 	, _properties(properties)
diff --git a/src/server/events/CreateGraph.hpp b/src/server/events/CreateGraph.hpp
index 6ea07957..dadb644e 100644
--- a/src/server/events/CreateGraph.hpp
+++ b/src/server/events/CreateGraph.hpp
@@ -40,12 +40,12 @@ namespace events {
 class CreateGraph : public Event
 {
 public:
-	CreateGraph(Engine&           engine,
-	            SPtr<Interface>   client,
-	            int32_t           id,
-	            SampleCount       timestamp,
-	            const Raul::Path& path,
-	            const Properties& properties);
+	CreateGraph(Engine&                engine,
+	            const SPtr<Interface>& client,
+	            int32_t                id,
+	            SampleCount            timestamp,
+	            const Raul::Path&      path,
+	            const Properties&      properties);
 
 	bool pre_process(PreProcessContext& ctx) override;
 	void execute(RunContext& context) override;
diff --git a/src/server/events/CreatePort.cpp b/src/server/events/CreatePort.cpp
index 09eb8cff..d1b4f114 100644
--- a/src/server/events/CreatePort.cpp
+++ b/src/server/events/CreatePort.cpp
@@ -40,12 +40,12 @@ namespace ingen {
 namespace server {
 namespace events {
 
-CreatePort::CreatePort(Engine&           engine,
-                       SPtr<Interface>   client,
-                       int32_t           id,
-                       SampleCount       timestamp,
-                       const Raul::Path& path,
-                       const Properties& properties)
+CreatePort::CreatePort(Engine&                engine,
+                       const SPtr<Interface>& client,
+                       int32_t                id,
+                       SampleCount            timestamp,
+                       const Raul::Path&      path,
+                       const Properties&      properties)
 	: Event(engine, client, id, timestamp)
 	, _path(path)
 	, _port_type(PortType::UNKNOWN)
diff --git a/src/server/events/CreatePort.hpp b/src/server/events/CreatePort.hpp
index 9c5bb396..8137328d 100644
--- a/src/server/events/CreatePort.hpp
+++ b/src/server/events/CreatePort.hpp
@@ -44,12 +44,12 @@ namespace events {
 class CreatePort : public Event
 {
 public:
-	CreatePort(Engine&           engine,
-	           SPtr<Interface>   client,
-	           int32_t           id,
-	           SampleCount       timestamp,
-	           const Raul::Path& path,
-	           const Properties& properties);
+	CreatePort(Engine&                engine,
+	           const SPtr<Interface>& client,
+	           int32_t                id,
+	           SampleCount            timestamp,
+	           const Raul::Path&      path,
+	           const Properties&      properties);
 
 	bool pre_process(PreProcessContext& ctx) override;
 	void execute(RunContext& context) override;
diff --git a/src/server/events/Delete.cpp b/src/server/events/Delete.cpp
index 0b46f3f4..5d605bca 100644
--- a/src/server/events/Delete.cpp
+++ b/src/server/events/Delete.cpp
@@ -43,10 +43,10 @@ namespace ingen {
 namespace server {
 namespace events {
 
-Delete::Delete(Engine&           engine,
-               SPtr<Interface>   client,
-               FrameTime         timestamp,
-               const ingen::Del& msg)
+Delete::Delete(Engine&                engine,
+               const SPtr<Interface>& client,
+               FrameTime              timestamp,
+               const ingen::Del&      msg)
 	: Event(engine, client, msg.seq, timestamp)
 	, _msg(msg)
 	, _engine_port(nullptr)
diff --git a/src/server/events/Delete.hpp b/src/server/events/Delete.hpp
index 14acac83..6b3149e9 100644
--- a/src/server/events/Delete.hpp
+++ b/src/server/events/Delete.hpp
@@ -45,10 +45,10 @@ class DisconnectAll;
 class Delete : public Event
 {
 public:
-	Delete(Engine&           engine,
-	       SPtr<Interface>   client,
-	       FrameTime         timestamp,
-	       const ingen::Del& msg);
+	Delete(Engine&                engine,
+	       const SPtr<Interface>& client,
+	       FrameTime              timestamp,
+	       const ingen::Del&      msg);
 
 	~Delete();
 
diff --git a/src/server/events/Delta.cpp b/src/server/events/Delta.cpp
index f5928c12..19e5bb20 100644
--- a/src/server/events/Delta.cpp
+++ b/src/server/events/Delta.cpp
@@ -48,10 +48,10 @@ class PreProcessContext;
 
 namespace events {
 
-Delta::Delta(Engine&           engine,
-             SPtr<Interface>   client,
-             SampleCount       timestamp,
-             const ingen::Put& msg)
+Delta::Delta(Engine&                engine,
+             const SPtr<Interface>& client,
+             SampleCount            timestamp,
+             const ingen::Put&      msg)
 	: Event(engine, client, msg.seq, timestamp)
 	, _create_event(nullptr)
 	, _subject(msg.uri)
@@ -67,10 +67,10 @@ Delta::Delta(Engine&           engine,
 	init();
 }
 
-Delta::Delta(Engine&             engine,
-             SPtr<Interface>     client,
-             SampleCount         timestamp,
-             const ingen::Delta& msg)
+Delta::Delta(Engine&                engine,
+             const SPtr<Interface>& client,
+             SampleCount            timestamp,
+             const ingen::Delta&    msg)
 	: Event(engine, client, msg.seq, timestamp)
 	, _create_event(nullptr)
 	, _subject(msg.uri)
@@ -88,7 +88,7 @@ Delta::Delta(Engine&             engine,
 }
 
 Delta::Delta(Engine&                   engine,
-             SPtr<Interface>           client,
+             const SPtr<Interface>&    client,
              SampleCount               timestamp,
              const ingen::SetProperty& msg)
 	: Event(engine, client, msg.seq, timestamp)
diff --git a/src/server/events/Delta.hpp b/src/server/events/Delta.hpp
index 4328ad83..2aa2ff90 100644
--- a/src/server/events/Delta.hpp
+++ b/src/server/events/Delta.hpp
@@ -47,18 +47,18 @@ class SetPortValue;
 class Delta : public Event
 {
 public:
-	Delta(Engine&           engine,
-	      SPtr<Interface>   client,
-	      SampleCount       timestamp,
-	      const ingen::Put& msg);
+	Delta(Engine&                engine,
+	      const SPtr<Interface>& client,
+	      SampleCount            timestamp,
+	      const ingen::Put&      msg);
 
-	Delta(Engine&             engine,
-	      SPtr<Interface>     client,
-	      SampleCount         timestamp,
-	      const ingen::Delta& msg);
+	Delta(Engine&                engine,
+	      const SPtr<Interface>& client,
+	      SampleCount            timestamp,
+	      const ingen::Delta&    msg);
 
 	Delta(Engine&                   engine,
-	      SPtr<Interface>           client,
+	      const SPtr<Interface>&    client,
 	      SampleCount               timestamp,
 	      const ingen::SetProperty& msg);
 
diff --git a/src/server/events/Disconnect.cpp b/src/server/events/Disconnect.cpp
index 349fb6ae..531d70af 100644
--- a/src/server/events/Disconnect.cpp
+++ b/src/server/events/Disconnect.cpp
@@ -44,7 +44,7 @@ namespace server {
 namespace events {
 
 Disconnect::Disconnect(Engine&                  engine,
-                       SPtr<Interface>          client,
+                       const SPtr<Interface>&   client,
                        SampleCount              timestamp,
                        const ingen::Disconnect& msg)
 	: Event(engine, client, msg.seq, timestamp)
diff --git a/src/server/events/Disconnect.hpp b/src/server/events/Disconnect.hpp
index 15872ba5..ec638c73 100644
--- a/src/server/events/Disconnect.hpp
+++ b/src/server/events/Disconnect.hpp
@@ -38,7 +38,7 @@ class Disconnect : public Event
 {
 public:
 	Disconnect(Engine&                  engine,
-	           SPtr<Interface>          client,
+	           const SPtr<Interface>&   client,
 	           SampleCount              timestamp,
 	           const ingen::Disconnect& msg);
 
diff --git a/src/server/events/DisconnectAll.cpp b/src/server/events/DisconnectAll.cpp
index 9c949480..ada51302 100644
--- a/src/server/events/DisconnectAll.cpp
+++ b/src/server/events/DisconnectAll.cpp
@@ -41,7 +41,7 @@ namespace server {
 namespace events {
 
 DisconnectAll::DisconnectAll(Engine&                     engine,
-                             SPtr<Interface>             client,
+                             const SPtr<Interface>&      client,
                              SampleCount                 timestamp,
                              const ingen::DisconnectAll& msg)
 	: Event(engine, client, msg.seq, timestamp)
diff --git a/src/server/events/DisconnectAll.hpp b/src/server/events/DisconnectAll.hpp
index 3edfedd6..9ab908c1 100644
--- a/src/server/events/DisconnectAll.hpp
+++ b/src/server/events/DisconnectAll.hpp
@@ -44,7 +44,7 @@ class DisconnectAll : public Event
 {
 public:
 	DisconnectAll(Engine&                     engine,
-	              SPtr<Interface>             client,
+	              const SPtr<Interface>&      client,
 	              SampleCount                 timestamp,
 	              const ingen::DisconnectAll& msg);
 
diff --git a/src/server/events/Get.cpp b/src/server/events/Get.cpp
index 167f5f91..7bb6fd2f 100644
--- a/src/server/events/Get.cpp
+++ b/src/server/events/Get.cpp
@@ -37,10 +37,10 @@ namespace ingen {
 namespace server {
 namespace events {
 
-Get::Get(Engine&           engine,
-         SPtr<Interface>   client,
-         SampleCount       timestamp,
-         const ingen::Get& msg)
+Get::Get(Engine&                engine,
+         const SPtr<Interface>& client,
+         SampleCount            timestamp,
+         const ingen::Get&      msg)
 	: Event(engine, client, msg.seq, timestamp)
 	, _msg(msg)
 	, _object(nullptr)
diff --git a/src/server/events/Get.hpp b/src/server/events/Get.hpp
index b23c7294..e24c9998 100644
--- a/src/server/events/Get.hpp
+++ b/src/server/events/Get.hpp
@@ -39,10 +39,10 @@ namespace events {
 class Get : public Event
 {
 public:
-	Get(Engine&           engine,
-	    SPtr<Interface>   client,
-	    SampleCount       timestamp,
-	    const ingen::Get& msg);
+	Get(Engine&                engine,
+	    const SPtr<Interface>& client,
+	    SampleCount            timestamp,
+	    const ingen::Get&      msg);
 
 	bool pre_process(PreProcessContext& ctx) override;
 	void execute(RunContext& context) override {}
diff --git a/src/server/events/Mark.cpp b/src/server/events/Mark.cpp
index 4f9b1261..314805f5 100644
--- a/src/server/events/Mark.cpp
+++ b/src/server/events/Mark.cpp
@@ -27,7 +27,7 @@ namespace server {
 namespace events {
 
 Mark::Mark(Engine&                   engine,
-           SPtr<Interface>           client,
+           const SPtr<Interface>&    client,
            SampleCount               timestamp,
            const ingen::BundleBegin& msg)
 	: Event(engine, client, msg.seq, timestamp)
@@ -36,7 +36,7 @@ Mark::Mark(Engine&                   engine,
 {}
 
 Mark::Mark(Engine&                 engine,
-           SPtr<Interface>         client,
+           const SPtr<Interface>&  client,
            SampleCount             timestamp,
            const ingen::BundleEnd& msg)
 	: Event(engine, client, msg.seq, timestamp)
diff --git a/src/server/events/Mark.hpp b/src/server/events/Mark.hpp
index ad8cb66b..c32c2588 100644
--- a/src/server/events/Mark.hpp
+++ b/src/server/events/Mark.hpp
@@ -41,12 +41,12 @@ class Mark : public Event
 {
 public:
 	Mark(Engine&                   engine,
-	     SPtr<Interface>           client,
+	     const SPtr<Interface>&    client,
 	     SampleCount               timestamp,
 	     const ingen::BundleBegin& msg);
 
 	Mark(Engine&                 engine,
-	     SPtr<Interface>         client,
+	     const SPtr<Interface>&  client,
 	     SampleCount             timestamp,
 	     const ingen::BundleEnd& msg);
 
diff --git a/src/server/events/Move.cpp b/src/server/events/Move.cpp
index c7478898..857be189 100644
--- a/src/server/events/Move.cpp
+++ b/src/server/events/Move.cpp
@@ -31,10 +31,10 @@ namespace ingen {
 namespace server {
 namespace events {
 
-Move::Move(Engine&           engine,
-           SPtr<Interface>   client,
-           SampleCount       timestamp,
-           const ingen::Move& msg)
+Move::Move(Engine&                engine,
+           const SPtr<Interface>& client,
+           SampleCount            timestamp,
+           const ingen::Move&     msg)
 	: Event(engine, client, msg.seq, timestamp)
 	, _msg(msg)
 {
diff --git a/src/server/events/Move.hpp b/src/server/events/Move.hpp
index 327b31b9..b4487b78 100644
--- a/src/server/events/Move.hpp
+++ b/src/server/events/Move.hpp
@@ -36,10 +36,10 @@ namespace events {
 class Move : public Event
 {
 public:
-	Move(Engine&            engine,
-	     SPtr<Interface>    client,
-	     SampleCount        timestamp,
-	     const ingen::Move& msg);
+	Move(Engine&                engine,
+	     const SPtr<Interface>& client,
+	     SampleCount            timestamp,
+	     const ingen::Move&     msg);
 
 	bool pre_process(PreProcessContext& ctx) override;
 	void execute(RunContext& context) override;
diff --git a/src/server/events/SetPortValue.cpp b/src/server/events/SetPortValue.cpp
index 9193f876..02f3f66b 100644
--- a/src/server/events/SetPortValue.cpp
+++ b/src/server/events/SetPortValue.cpp
@@ -37,14 +37,14 @@ namespace server {
 namespace events {
 
 /** Internal */
-SetPortValue::SetPortValue(Engine&         engine,
-                           SPtr<Interface> client,
-                           int32_t         id,
-                           SampleCount     timestamp,
-                           PortImpl*       port,
-                           const Atom&     value,
-                           bool            activity,
-                           bool            synthetic)
+SetPortValue::SetPortValue(Engine&                engine,
+                           const SPtr<Interface>& client,
+                           int32_t                id,
+                           SampleCount            timestamp,
+                           PortImpl*              port,
+                           const Atom&            value,
+                           bool                   activity,
+                           bool                   synthetic)
 	: Event(engine, client, id, timestamp)
 	, _port(port)
 	, _value(value)
diff --git a/src/server/events/SetPortValue.hpp b/src/server/events/SetPortValue.hpp
index 1e7c7250..99d55af3 100644
--- a/src/server/events/SetPortValue.hpp
+++ b/src/server/events/SetPortValue.hpp
@@ -40,14 +40,14 @@ namespace events {
 class SetPortValue : public Event
 {
 public:
-	SetPortValue(Engine&         engine,
-	             SPtr<Interface> client,
-	             int32_t         id,
-	             SampleCount     timestamp,
-	             PortImpl*       port,
-	             const Atom&     value,
-	             bool            activity,
-	             bool            synthetic = false);
+	SetPortValue(Engine&                engine,
+	             const SPtr<Interface>& client,
+	             int32_t                id,
+	             SampleCount            timestamp,
+	             PortImpl*              port,
+	             const Atom&            value,
+	             bool                   activity,
+	             bool                   synthetic = false);
 
 	bool pre_process(PreProcessContext& ctx) override;
 	void execute(RunContext& context) override;
diff --git a/src/server/events/Undo.cpp b/src/server/events/Undo.cpp
index 3a3bdbe2..0741e60d 100644
--- a/src/server/events/Undo.cpp
+++ b/src/server/events/Undo.cpp
@@ -27,24 +27,24 @@ namespace ingen {
 namespace server {
 namespace events {
 
-Undo::Undo(Engine&            engine,
-           SPtr<Interface>    client,
-           SampleCount        timestamp,
-           const ingen::Undo& msg)
+Undo::Undo(Engine&                engine,
+           const SPtr<Interface>& client,
+           SampleCount            timestamp,
+           const ingen::Undo&     msg)
 	: Event(engine, client, msg.seq, timestamp)
 	, _is_redo(false)
 {}
 
-Undo::Undo(Engine&            engine,
-           SPtr<Interface>    client,
-           SampleCount        timestamp,
-           const ingen::Redo& msg)
+Undo::Undo(Engine&                engine,
+           const SPtr<Interface>& client,
+           SampleCount            timestamp,
+           const ingen::Redo&     msg)
 	: Event(engine, client, msg.seq, timestamp)
 	, _is_redo(true)
 {}
 
 bool
-Undo::pre_process(PreProcessContext& ctx)
+Undo::pre_process(PreProcessContext&)
 {
 	const UPtr<UndoStack>& stack = _is_redo ? _engine.redo_stack() : _engine.undo_stack();
 	const Event::Mode      mode  = _is_redo ? Event::Mode::REDO    : Event::Mode::UNDO;
diff --git a/src/server/events/Undo.hpp b/src/server/events/Undo.hpp
index f8469960..e36ebaad 100644
--- a/src/server/events/Undo.hpp
+++ b/src/server/events/Undo.hpp
@@ -32,15 +32,15 @@ namespace events {
 class Undo : public Event
 {
 public:
-	Undo(Engine&            engine,
-	     SPtr<Interface>    client,
-	     SampleCount        timestamp,
-	     const ingen::Undo& msg);
-
-	Undo(Engine&            engine,
-	     SPtr<Interface>    client,
-	     SampleCount        timestamp,
-	     const ingen::Redo& msg);
+	Undo(Engine&                engine,
+	     const SPtr<Interface>& client,
+	     SampleCount            timestamp,
+	     const ingen::Undo&     msg);
+
+	Undo(Engine&                engine,
+	     const SPtr<Interface>& client,
+	     SampleCount            timestamp,
+	     const ingen::Redo&     msg);
 
 	bool pre_process(PreProcessContext& ctx) override;
 	void execute(RunContext& context) override;
diff --git a/src/server/ingen_lv2.cpp b/src/server/ingen_lv2.cpp
index 5ef3a321..57663344 100644
--- a/src/server/ingen_lv2.cpp
+++ b/src/server/ingen_lv2.cpp
@@ -425,7 +425,7 @@ using namespace ingen;
 using namespace ingen::server;
 
 static void
-ingen_lv2_main(SPtr<Engine> engine, const SPtr<LV2Driver>& driver)
+ingen_lv2_main(const SPtr<Engine>& engine, const SPtr<LV2Driver>& driver)
 {
 	while (true) {
 		// Wait until there is work to be done