output/httpd/Page: use std::shared_ptr instead of class RefCount

src/output/plugins/httpd/HttpdClient.cxx

@@ -33,16 +33,6 @@
 
 HttpdClient::~HttpdClient()
 {
-	if (state == RESPONSE) {
-		if (current_page != nullptr)
-			current_page->Unref();
-
-		ClearQueue();
-	}
-
-	if (metadata)
-		metadata->Unref();
-
 	if (IsDefined())
 		BufferedSocket::Close();
 }
@@ -217,15 +207,13 @@ HttpdClient::ClearQueue()
 	assert(state == RESPONSE);
 
 	while (!pages.empty()) {
-		Page *page = pages.front();
-		pages.pop();
-
 #ifndef NDEBUG
+		auto &page = pages.front();
 		assert(queue_size >= page->GetSize());
 		queue_size -= page->GetSize();
 #endif
 
-		page->Unref();
+		pages.pop();
 	}
 
 	assert(queue_size == 0);
@@ -372,8 +360,7 @@ HttpdClient::TryWrite()
 			metadata_fill += nbytes;
 
 		if (current_position >= current_page->GetSize()) {
-			current_page->Unref();
-			current_page = nullptr;
+			current_page.reset();
 
 			if (pages.empty())
 				/* all pages are sent: remove the
@@ -386,7 +373,7 @@ HttpdClient::TryWrite()
 }
 
 void
-HttpdClient::PushPage(Page *page)
+HttpdClient::PushPage(PagePtr page)
 {
 	if (state != RESPONSE)
 		/* the client is still writing the HTTP request */
@@ -398,25 +385,18 @@ HttpdClient::PushPage(Page *page)
 		ClearQueue();
 	}
 
-	page->Ref();
-	pages.push(page);
 	queue_size += page->GetSize();
+	pages.emplace(std::move(page));
 
 	ScheduleWrite();
 }
 
 void
-HttpdClient::PushMetaData(Page *page)
+HttpdClient::PushMetaData(PagePtr page)
 {
 	assert(page != nullptr);
 
-	if (metadata) {
-		metadata->Unref();
-		metadata = nullptr;
-	}
-
-	page->Ref();
-	metadata = page;
+	metadata = std::move(page);
 	metadata_sent = false;
 }
 

src/output/plugins/httpd/HttpdClient.hxx

@@ -20,6 +20,7 @@
 #ifndef MPD_OUTPUT_HTTPD_CLIENT_HXX
 #define MPD_OUTPUT_HTTPD_CLIENT_HXX
 
+#include "Page.hxx"
 #include "event/BufferedSocket.hxx"
 #include "Compiler.h"
 
@@ -32,7 +33,6 @@
 #include <stddef.h>
 
 class HttpdOutput;
-class Page;
 
 class HttpdClient final
 	: BufferedSocket,
@@ -59,7 +59,7 @@ class HttpdClient final
 	/**
 	 * A queue of #Page objects to be sent to the client.
 	 */
-	std::queue<Page *, std::list<Page *>> pages;
+	std::queue<PagePtr, std::list<PagePtr>> pages;
 
 	/**
 	 * The sum of all page sizes in #pages.
@@ -69,7 +69,7 @@ class HttpdClient final
 	/**
 	 * The #page which is currently being sent to the client.
 	 */
-	Page *current_page;
+	PagePtr current_page;
 
 	/**
 	 * The amount of bytes which were already sent from
@@ -113,7 +113,7 @@ class HttpdClient final
 	/**
 	 * The metadata as #Page which is currently being sent to the client.
 	 */
-	Page *metadata;
+	PagePtr metadata;
 
 	/*
 	 * The amount of bytes which were already sent from the metadata.
@@ -178,12 +178,12 @@ public:
 	/**
 	 * Appends a page to the client's queue.
 	 */
-	void PushPage(Page *page);
+	void PushPage(PagePtr page);
 
 	/**
 	 * Sends the passed metadata.
 	 */
-	void PushMetaData(Page *page);
+	void PushMetaData(PagePtr page);
 
 private:
 	void ClearQueue();

src/output/plugins/httpd/HttpdInternal.hxx

@@ -44,7 +44,6 @@ struct ConfigBlock;
 class EventLoop;
 class ServerSocket;
 class HttpdClient;
-class Page;
 class PreparedEncoder;
 class Encoder;
 struct Tag;
@@ -102,12 +101,12 @@ private:
 	/**
 	 * The header page, which is sent to every client on connect.
 	 */
-	Page *header;
+	PagePtr header;
 
 	/**
 	 * The metadata, which is sent to every client.
 	 */
-	Page *metadata;
+	PagePtr metadata;
 
 	/**
 	 * The page queue, i.e. pages from the encoder to be
@@ -115,7 +114,7 @@ private:
 	 * pass pages from the OutputThread to the IOThread.  It is
 	 * protected by #mutex, and removing signals #cond.
 	 */
-	std::queue<Page *, std::list<Page *>> pages;
+	std::queue<PagePtr, std::list<PagePtr>> pages;
 
  public:
 	/**
@@ -234,14 +233,14 @@ public:
 	 * Reads data from the encoder (as much as available) and
 	 * returns it as a new #page object.
 	 */
-	Page *ReadPage();
+	PagePtr ReadPage();
 
 	/**
 	 * Broadcasts a page struct to all clients.
 	 *
 	 * Mutext must not be locked.
 	 */
-	void BroadcastPage(Page *page);
+	void BroadcastPage(PagePtr page);
 
 	/**
 	 * Broadcasts data from the encoder to all clients.

src/output/plugins/httpd/HttpdOutputPlugin.cxx

@@ -90,9 +90,6 @@ HttpdOutput::HttpdOutput(EventLoop &_loop, const ConfigBlock &block)
 
 HttpdOutput::~HttpdOutput()
 {
-	if (metadata != nullptr)
-		metadata->Unref();
-
 	delete prepared_encoder;
 }
 
@@ -147,13 +144,11 @@ HttpdOutput::RunDeferred()
 	const std::lock_guard<Mutex> protect(mutex);
 
 	while (!pages.empty()) {
-		Page *page = pages.front();
+		PagePtr page = std::move(pages.front());
 		pages.pop();
 
 		for (auto &client : clients)
 			client.PushPage(page);
-
-		page->Unref();
 	}
 
 	/* wake up the client that may be waiting for the queue to be
@@ -204,7 +199,7 @@ HttpdOutput::OnAccept(int fd, SocketAddress address, gcc_unused int uid)
 	}
 }
 
-Page *
+PagePtr
 HttpdOutput::ReadPage()
 {
 	if (unflushed_input >= 65536) {
@@ -235,7 +230,7 @@ HttpdOutput::ReadPage()
 	if (size == 0)
 		return nullptr;
 
-	return Page::Copy(buffer, size);
+	return std::make_shared<Page>(buffer, size);
 }
 
 inline void
@@ -282,8 +277,7 @@ HttpdOutput::Close()
 			clients.clear_and_dispose(DeleteDisposer());
 		});
 
-	if (header != nullptr)
-		header->Unref();
+	header.reset();
 
 	delete encoder;
 }
@@ -326,13 +320,12 @@ HttpdOutput::Delay() const
 }
 
 void
-HttpdOutput::BroadcastPage(Page *page)
+HttpdOutput::BroadcastPage(PagePtr page)
 {
 	assert(page != nullptr);
 
 	mutex.lock();
-	pages.push(page);
-	page->Ref();
+	pages.emplace(std::move(page));
 	mutex.unlock();
 
 	DeferredMonitor::Schedule();
@@ -346,7 +339,7 @@ HttpdOutput::BroadcastFromEncoder()
 	while (!pages.empty())
 		cond.wait(mutex);
 
-	Page *page;
+	PagePtr page;
 	while ((page = ReadPage()) != nullptr)
 		pages.push(page);
 
@@ -418,19 +411,14 @@ HttpdOutput::SendTag(const Tag &tag)
 		   used as the new "header" page, which is sent to all
 		   new clients */
 
-		Page *page = ReadPage();
+		auto page = ReadPage();
 		if (page != nullptr) {
-			if (header != nullptr)
-				header->Unref();
-			header = page;
+			header = std::move(page);
 			BroadcastPage(page);
 		}
 	} else {
 		/* use Icy-Metadata */
 
-		if (metadata != nullptr)
-			metadata->Unref();
-
 		static constexpr TagType types[] = {
 			TAG_ALBUM, TAG_ARTIST, TAG_TITLE,
 			TAG_NUM_OF_ITEM_TYPES
@@ -451,9 +439,8 @@ HttpdOutput::CancelAllClients()
 	const std::lock_guard<Mutex> protect(mutex);
 
 	while (!pages.empty()) {
-		Page *page = pages.front();
+		PagePtr page = std::move(pages.front());
 		pages.pop();
-		page->Unref();
 	}
 
 	for (auto &client : clients)

src/output/plugins/httpd/IcyMetaDataServer.cxx

@@ -19,7 +19,6 @@
 
 #include "config.h"
 #include "IcyMetaDataServer.hxx"
-#include "Page.hxx"
 #include "tag/Tag.hxx"
 #include "util/FormatString.hxx"
 #include "util/AllocatedString.hxx"
@@ -82,7 +81,7 @@ icy_server_metadata_string(const char *stream_title, const char* stream_url)
 	return icy_metadata;
 }
 
-Page *
+PagePtr
 icy_server_metadata_page(const Tag &tag, const TagType *types)
 {
 	const char *tag_items[TAG_NUM_OF_ITEM_TYPES];
@@ -113,5 +112,6 @@ icy_server_metadata_page(const Tag &tag, const TagType *types)
 	if (icy_string.IsNull())
 		return nullptr;
 
-	return Page::Copy(icy_string.c_str(), uint8_t(icy_string[0]) * 16 + 1);
+	return std::make_shared<Page>(icy_string.c_str(),
+				      uint8_t(icy_string[0]) * 16 + 1);
 }

src/output/plugins/httpd/IcyMetaDataServer.hxx

@@ -20,10 +20,10 @@
 #ifndef MPD_ICY_META_DATA_SERVER_HXX
 #define MPD_ICY_META_DATA_SERVER_HXX
 
+#include "Page.hxx"
 #include "tag/Type.h"
 
 struct Tag;
-class Page;
 template<typename T> class AllocatedString;
 
 AllocatedString<char>
@@ -31,7 +31,7 @@ icy_server_metadata_header(const char *name,
 			   const char *genre, const char *url,
 			   const char *content_type, int metaint);
 
-Page *
+PagePtr
 icy_server_metadata_page(const Tag &tag, const TagType *types);
 
 #endif

src/output/plugins/httpd/Page.cxx

@@ -24,29 +24,8 @@
 #include <string.h>
 #include <stdlib.h>
 
-Page *
-Page::Create(size_t size)
+Page::Page(const void *data, size_t size)
+	:buffer(size)
 {
-	return new Page(size);
-}
-
-Page *
-Page::Copy(const void *data, size_t size)
-{
-	assert(data != nullptr);
-
-	Page *page = Create(size);
-	memcpy(&page->buffer.front(), data, size);
-	return page;
-}
-
-bool
-Page::Unref()
-{
-	bool unused = ref.Decrement();
-
-	if (unused)
-		delete this;
-
-	return unused;
+	memcpy(&buffer.front(), data, size);
 }

src/output/plugins/httpd/Page.hxx

@@ -17,17 +17,13 @@
  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  */
 
-/** \file
- *
- * This is a library which manages reference counted buffers.
- */
-
 #ifndef MPD_PAGE_HXX
 #define MPD_PAGE_HXX
 
-#include "util/RefCount.hxx"
 #include "util/AllocatedArray.hxx"
 
+#include <memory>
+
 #include <stddef.h>
 #include <stdint.h>
 
@@ -37,54 +33,14 @@
  * instances hold references to one buffer.
  */
 class Page {
-	/**
-	 * The number of references to this buffer.  This library uses
-	 * atomic functions to access it, i.e. no locks are required.
-	 * As soon as this attribute reaches zero, the buffer is
-	 * freed.
-	 */
-	RefCount ref;
-
 	AllocatedArray<uint8_t> buffer;
 
-protected:
+public:
 	explicit Page(size_t _size):buffer(_size) {}
 	explicit Page(AllocatedArray<uint8_t> &&_buffer)
 		:buffer(std::move(_buffer)) {}
 
-	~Page() = default;
-
-	/**
-	 * Allocates a new #Page object, without filling the data
-	 * element.
-	 */
-	static Page *Create(size_t size);
-
-public:
-	/**
-	 * Creates a new #page object, and copies data from the
-	 * specified buffer.  It is initialized with a reference count
-	 * of 1.
-	 *
-	 * @param data the source buffer
-	 * @param size the size of the source buffer
-	 */
-	static Page *Copy(const void *data, size_t size);
-
-	/**
-	 * Increases the reference counter.
-	 */
-	void Ref() {
-		ref.Increment();
-	}
-
-	/**
-	 * Decreases the reference counter.  If it reaches zero, the #page is
-	 * freed.
-	 *
-	 * @return true if the #page has been freed
-	 */
-	bool Unref();
+	Page(const void *data, size_t size);
 
 	size_t GetSize() const {
 		return buffer.size();
@@ -95,4 +51,6 @@ public:
 	}
 };
 
+typedef std::shared_ptr<Page> PagePtr;
+
 #endif