output/{recorder,httpd,shout}: use std::unique_ptr to manage PreparedEncoder pointer

src/output/plugins/RecorderOutputPlugin.cxx

@@ -35,6 +35,7 @@
 #include "util/ScopeExit.hxx"
 
 #include <stdexcept>
+#include <memory>
 
 #include <assert.h>
 #include <stdlib.h>
@@ -45,7 +46,7 @@ class RecorderOutput final : AudioOutput {
 	/**
 	 * The configured encoder plugin.
 	 */
-	PreparedEncoder *prepared_encoder = nullptr;
+	std::unique_ptr<PreparedEncoder> prepared_encoder;
 	Encoder *encoder;
 
 	/**
@@ -72,10 +73,6 @@ class RecorderOutput final : AudioOutput {
 
 	RecorderOutput(const ConfigBlock &block);
 
-	~RecorderOutput() {
-		delete prepared_encoder;
-	}
-
 public:
 	static AudioOutput *Create(EventLoop &, const ConfigBlock &block) {
 		return new RecorderOutput(block);
@@ -136,7 +133,7 @@ RecorderOutput::RecorderOutput(const ConfigBlock &block)
 
 	/* initialize encoder */
 
-	prepared_encoder = encoder_init(*encoder_plugin, block);
+	prepared_encoder.reset(encoder_init(*encoder_plugin, block));
 }
 
 inline void

src/output/plugins/ShoutOutputPlugin.cxx

@@ -30,6 +30,7 @@
 #include <shout/shout.h>
 
 #include <stdexcept>
+#include <memory>
 
 #include <assert.h>
 #include <stdlib.h>
@@ -42,7 +43,7 @@ struct ShoutOutput final : AudioOutput {
 	shout_t *shout_conn;
 	shout_metadata_t *shout_meta;
 
-	PreparedEncoder *prepared_encoder = nullptr;
+	std::unique_ptr<PreparedEncoder> prepared_encoder;
 	Encoder *encoder;
 
 	float quality = -2.0;
@@ -162,7 +163,7 @@ ShoutOutput::ShoutOutput(const ConfigBlock &block)
 		throw FormatRuntimeError("couldn't find shout encoder plugin \"%s\"",
 					 encoding);
 
-	prepared_encoder = encoder_init(*encoder_plugin, block);
+	prepared_encoder.reset(encoder_init(*encoder_plugin, block));
 
 	unsigned shout_format;
 	if (strcmp(encoding, "mp3") == 0 || strcmp(encoding, "lame") == 0)
@@ -243,8 +244,6 @@ ShoutOutput::~ShoutOutput()
 	shout_init_count--;
 	if (shout_init_count == 0)
 		shout_shutdown();
-
-	delete prepared_encoder;
 }
 
 AudioOutput *

src/output/plugins/httpd/HttpdInternal.hxx

@@ -39,6 +39,7 @@
 
 #include <queue>
 #include <list>
+#include <memory>
 
 struct ConfigBlock;
 class EventLoop;
@@ -60,7 +61,7 @@ class HttpdOutput final : AudioOutput, ServerSocket {
 	/**
 	 * The configured encoder plugin.
 	 */
-	PreparedEncoder *prepared_encoder = nullptr;
+	std::unique_ptr<PreparedEncoder> prepared_encoder;
 	Encoder *encoder = nullptr;
 
 	/**
@@ -152,7 +153,6 @@ private:
 
 public:
 	HttpdOutput(EventLoop &_loop, const ConfigBlock &block);
-	~HttpdOutput();
 
 	static AudioOutput *Create(EventLoop &event_loop,
 				   const ConfigBlock &block) {

src/output/plugins/httpd/HttpdOutputPlugin.cxx

@@ -79,7 +79,7 @@ HttpdOutput::HttpdOutput(EventLoop &_loop, const ConfigBlock &block)
 
 	/* initialize encoder */
 
-	prepared_encoder = encoder_init(*encoder_plugin, block);
+	prepared_encoder.reset(encoder_init(*encoder_plugin, block));
 
 	/* determine content type */
 	content_type = prepared_encoder->GetMimeType();
@@ -87,11 +87,6 @@ HttpdOutput::HttpdOutput(EventLoop &_loop, const ConfigBlock &block)
 		content_type = "application/octet-stream";
 }
 
-HttpdOutput::~HttpdOutput()
-{
-	delete prepared_encoder;
-}
-
 inline void
 HttpdOutput::Bind()
 {