output/Interface: convert to abstract class

Yet another C-style vtable replaced with C++.

src/output/plugins/httpd/HttpdInternal.hxx

@@ -26,8 +26,7 @@
 #define MPD_OUTPUT_HTTPD_INTERNAL_H
 
 #include "HttpdClient.hxx"
-#include "output/Wrapper.hxx"
-#include "output/Filtered.hxx"
+#include "output/Interface.hxx"
 #include "output/Timer.hxx"
 #include "thread/Mutex.hxx"
 #include "thread/Cond.hxx"
@@ -49,11 +48,7 @@ class PreparedEncoder;
 class Encoder;
 struct Tag;
 
-class HttpdOutput final : ServerSocket, DeferredMonitor {
-	friend struct AudioOutputWrapper<HttpdOutput>;
-
-	AudioOutput base;
-
+class HttpdOutput final : AudioOutput, ServerSocket, DeferredMonitor {
 	/**
 	 * True if the audio output is open and accepts client
 	 * connections.
@@ -157,11 +152,9 @@ public:
 	HttpdOutput(EventLoop &_loop, const ConfigBlock &block);
 	~HttpdOutput();
 
-	static HttpdOutput *Create(EventLoop &event_loop,
-				   const ConfigBlock &block);
-
-	static constexpr HttpdOutput *Cast(AudioOutput *ao) {
-		return &ContainerCast(*ao, &HttpdOutput::base);
+	static AudioOutput *Create(EventLoop &event_loop,
+				   const ConfigBlock &block) {
+		return new HttpdOutput(event_loop, block);
 	}
 
 	using DeferredMonitor::GetEventLoop;
@@ -169,11 +162,11 @@ public:
 	void Bind();
 	void Unbind();
 
-	void Enable() {
+	void Enable() override {
 		Bind();
 	}
 
-	void Disable() {
+	void Disable() noexcept override {
 		Unbind();
 	}
 
@@ -187,12 +180,12 @@ public:
 	/**
 	 * Caller must lock the mutex.
 	 */
-	void Open(AudioFormat &audio_format);
+	void Open(AudioFormat &audio_format) override;
 
 	/**
 	 * Caller must lock the mutex.
 	 */
-	void Close();
+	void Close() noexcept override;
 
 	/**
 	 * Check whether there is at least one client.
@@ -227,7 +220,7 @@ public:
 	void SendHeader(HttpdClient &client) const;
 
 	gcc_pure
-	std::chrono::steady_clock::duration Delay() const noexcept;
+	std::chrono::steady_clock::duration Delay() const noexcept override;
 
 	/**
 	 * Reads data from the encoder (as much as available) and
@@ -252,14 +245,14 @@ public:
 	 */
 	void EncodeAndPlay(const void *chunk, size_t size);
 
-	void SendTag(const Tag &tag);
+	void SendTag(const Tag &tag) override;
 
-	size_t Play(const void *chunk, size_t size);
+	size_t Play(const void *chunk, size_t size) override;
 
 	void CancelAllClients();
 
-	void Cancel();
-	bool Pause();
+	void Cancel() noexcept override;
+	bool Pause() noexcept override;
 
 private:
 	virtual void RunDeferred() override;

src/output/plugins/httpd/HttpdOutputPlugin.cxx

@@ -50,8 +50,8 @@ const Domain httpd_output_domain("httpd_output");
 
 inline
 HttpdOutput::HttpdOutput(EventLoop &_loop, const ConfigBlock &block)
-	:ServerSocket(_loop), DeferredMonitor(_loop),
-	 base(httpd_output_plugin),
+	:AudioOutput(FLAG_ENABLE_DISABLE|FLAG_PAUSE),
+	 ServerSocket(_loop), DeferredMonitor(_loop),
 	 encoder(nullptr), unflushed_input(0),
 	 metadata(nullptr)
 {
@@ -113,12 +113,6 @@ HttpdOutput::Unbind()
 		});
 }
 
-HttpdOutput *
-HttpdOutput::Create(EventLoop &event_loop, const ConfigBlock &block)
-{
-	return new HttpdOutput(event_loop, block);
-}
-
 /**
  * Creates a new #HttpdClient object and adds it into the
  * HttpdOutput.clients linked list.
@@ -246,7 +240,7 @@ HttpdOutput::OpenEncoder(AudioFormat &audio_format)
 	unflushed_input = 0;
 }
 
-inline void
+void
 HttpdOutput::Open(AudioFormat &audio_format)
 {
 	assert(!open);
@@ -264,8 +258,8 @@ HttpdOutput::Open(AudioFormat &audio_format)
 	pause = false;
 }
 
-inline void
-HttpdOutput::Close()
+void
+HttpdOutput::Close() noexcept
 {
 	assert(open);
 
@@ -300,7 +294,7 @@ HttpdOutput::SendHeader(HttpdClient &client) const
 		client.PushPage(header);
 }
 
-inline std::chrono::steady_clock::duration
+std::chrono::steady_clock::duration
 HttpdOutput::Delay() const noexcept
 {
 	if (!LockHasClients() && pause) {
@@ -367,7 +361,7 @@ HttpdOutput::EncodeAndPlay(const void *chunk, size_t size)
 	BroadcastFromEncoder();
 }
 
-inline size_t
+size_t
 HttpdOutput::Play(const void *chunk, size_t size)
 {
 	pause = false;
@@ -383,7 +377,7 @@ HttpdOutput::Play(const void *chunk, size_t size)
 }
 
 bool
-HttpdOutput::Pause()
+HttpdOutput::Pause() noexcept
 {
 	pause = true;
 
@@ -395,7 +389,7 @@ HttpdOutput::Pause()
 	return true;
 }
 
-inline void
+void
 HttpdOutput::SendTag(const Tag &tag)
 {
 	if (encoder->ImplementsTag()) {
@@ -463,29 +457,16 @@ HttpdOutput::CancelAllClients()
 }
 
 void
-HttpdOutput::Cancel()
+HttpdOutput::Cancel() noexcept
 {
 	BlockingCall(GetEventLoop(), [this](){
 			CancelAllClients();
 		});
 }
 
-typedef AudioOutputWrapper<HttpdOutput> Wrapper;
-
 const struct AudioOutputPlugin httpd_output_plugin = {
 	"httpd",
 	nullptr,
-	&Wrapper::Init,
-	&Wrapper::Finish,
-	&Wrapper::Enable,
-	&Wrapper::Disable,
-	&Wrapper::Open,
-	&Wrapper::Close,
-	&Wrapper::Delay,
-	&Wrapper::SendTag,
-	&Wrapper::Play,
-	nullptr,
-	&Wrapper::Cancel,
-	&Wrapper::Pause,
+	&HttpdOutput::Create,
 	nullptr,
 };