input/InputStream: ReadTag() returns std::unique_ptr<Tag>

src/decoder/Bridge.cxx

@@ -223,7 +223,7 @@ bool
 DecoderBridge::UpdateStreamTag(InputStream *is)
 {
 	auto *tag = is != nullptr
-		? is->LockReadTag()
+		? is->LockReadTag().release()
 		: nullptr;
 	if (tag == nullptr) {
 		tag = song_tag;

src/input/AsyncInputStream.cxx

@@ -45,15 +45,19 @@ AsyncInputStream::AsyncInputStream(EventLoop &event_loop, const char *_url,
 
 AsyncInputStream::~AsyncInputStream()
 {
-	delete tag;
-
 	buffer.Clear();
 }
 
 void
-AsyncInputStream::SetTag(Tag *_tag) noexcept
+AsyncInputStream::SetTag(std::unique_ptr<Tag> _tag) noexcept
+{
+	tag = std::move(_tag);
+}
+
+void
+AsyncInputStream::ClearTag() noexcept
 {
-	delete std::exchange(tag, _tag);
+	tag.reset();
 }
 
 void
@@ -151,7 +155,7 @@ AsyncInputStream::SeekDone() noexcept
 	cond.broadcast();
 }
 
-Tag *
+std::unique_ptr<Tag>
 AsyncInputStream::ReadTag()
 {
 	return std::exchange(tag, nullptr);

src/input/AsyncInputStream.hxx

@@ -61,7 +61,7 @@ class AsyncInputStream : public InputStream {
 	 * The #Tag object ready to be requested via
 	 * InputStream::ReadTag().
 	 */
-	Tag *tag = nullptr;
+	std::unique_ptr<Tag> tag;
 
 	offset_type seek_offset;
 
@@ -84,7 +84,7 @@ public:
 	void Check() final;
 	bool IsEOF() noexcept final;
 	void Seek(offset_type new_offset) final;
-	Tag *ReadTag() final;
+	std::unique_ptr<Tag> ReadTag() final;
 	bool IsAvailable() noexcept final;
 	size_t Read(void *ptr, size_t read_size) final;
 
@@ -92,11 +92,8 @@ protected:
 	/**
 	 * Pass an tag from the I/O thread to the client thread.
 	 */
-	void SetTag(Tag *_tag) noexcept;
-
-	void ClearTag() noexcept {
-		SetTag(nullptr);
-	}
+	void SetTag(std::unique_ptr<Tag> _tag) noexcept;
+	void ClearTag() noexcept;
 
 	void Pause() noexcept;
 

src/input/IcyInputStream.cxx

@@ -38,22 +38,23 @@ IcyInputStream::Update()
 		offset = override_offset;
 }
 
-Tag *
+std::unique_ptr<Tag>
 IcyInputStream::ReadTag()
 {
-	Tag *new_input_tag = ProxyInputStream::ReadTag();
+	auto new_input_tag = ProxyInputStream::ReadTag();
 	if (!IsEnabled())
 		return new_input_tag;
 
+	const bool had_new_input_tag = !!new_input_tag;
 	if (new_input_tag != nullptr)
-		input_tag.reset(new_input_tag);
+		input_tag = std::move(new_input_tag);
 
 	auto new_icy_tag = parser.ReadTag();
 	const bool had_new_icy_tag = !!new_icy_tag;
 	if (new_icy_tag != nullptr)
 		icy_tag = std::move(new_icy_tag);
 
-	if (new_input_tag == nullptr && !had_new_icy_tag)
+	if (!had_new_input_tag && !had_new_icy_tag)
 		/* no change */
 		return nullptr;
 
@@ -62,12 +63,12 @@ IcyInputStream::ReadTag()
 		return nullptr;
 
 	if (input_tag == nullptr)
-		return new Tag(*icy_tag);
+		return std::make_unique<Tag>(*icy_tag);
 
 	if (icy_tag == nullptr)
-		return new Tag(*input_tag);
+		return std::make_unique<Tag>(*input_tag);
 
-	return Tag::Merge(*input_tag, *icy_tag).release();
+	return Tag::Merge(*input_tag, *icy_tag);
 }
 
 size_t

src/input/IcyInputStream.hxx

@@ -63,7 +63,7 @@ public:
 
 	/* virtual methods from InputStream */
 	void Update() override;
-	Tag *ReadTag() override;
+	std::unique_ptr<Tag> ReadTag() override;
 	size_t Read(void *ptr, size_t size) override;
 };
 

src/input/InputStream.cxx

@@ -19,6 +19,7 @@
 
 #include "config.h"
 #include "InputStream.hxx"
+#include "tag/Tag.hxx"
 #include "thread/Cond.hxx"
 #include "util/StringCompare.hxx"
 
@@ -107,13 +108,13 @@ InputStream::LockSkip(offset_type _offset)
 	Skip(_offset);
 }
 
-Tag *
+std::unique_ptr<Tag>
 InputStream::ReadTag()
 {
 	return nullptr;
 }
 
-Tag *
+std::unique_ptr<Tag>
 InputStream::LockReadTag()
 {
 	const std::lock_guard<Mutex> protect(mutex);

src/input/InputStream.hxx

@@ -27,6 +27,7 @@
 #include "Compiler.h"
 
 #include <string>
+#include <memory>
 
 #include <assert.h>
 
@@ -322,18 +323,16 @@ public:
 	 *
 	 * The caller must lock the mutex.
 	 *
-	 * @return a tag object which must be freed by the caller, or
-	 * nullptr if the tag has not changed since the last call
+	 * @return a tag object or nullptr if the tag has not changed
+	 * since the last call
 	 */
-	gcc_malloc
-	virtual Tag *ReadTag();
+	virtual std::unique_ptr<Tag> ReadTag();
 
 	/**
 	 * Wrapper for ReadTag() which locks and unlocks the mutex;
 	 * the caller must not be holding it already.
 	 */
-	gcc_malloc
-	Tag *LockReadTag();
+	std::unique_ptr<Tag> LockReadTag();
 
 	/**
 	 * Returns true if the next read operation will not block: either data

src/input/ProxyInputStream.cxx

@@ -19,6 +19,7 @@
 
 #include "config.h"
 #include "ProxyInputStream.hxx"
+#include "tag/Tag.hxx"
 
 ProxyInputStream::ProxyInputStream(InputStream *_input)
 	:InputStream(_input->GetURI(), _input->mutex, _input->cond),
@@ -75,7 +76,7 @@ ProxyInputStream::IsEOF() noexcept
 	return input.IsEOF();
 }
 
-Tag *
+std::unique_ptr<Tag>
 ProxyInputStream::ReadTag()
 {
 	return input.ReadTag();

src/input/ProxyInputStream.hxx

@@ -47,7 +47,7 @@ public:
 	void Update() override;
 	void Seek(offset_type new_offset) override;
 	bool IsEOF() noexcept override;
-	Tag *ReadTag() override;
+	std::unique_ptr<Tag> ReadTag() override;
 	bool IsAvailable() noexcept override;
 	size_t Read(void *ptr, size_t read_size) override;
 

src/input/plugins/CurlInputPlugin.cxx

@@ -223,7 +223,7 @@ CurlInputStream::OnHeaders(unsigned status,
 		TagBuilder tag_builder;
 		tag_builder.AddItem(TAG_NAME, i->second.c_str());
 
-		SetTag(tag_builder.CommitNew().release());
+		SetTag(tag_builder.CommitNew());
 	}
 
 	if (!icy->IsEnabled()) {

test/run_input.cxx

@@ -82,11 +82,12 @@ dump_input_stream(InputStream *is)
 	/* read data and tags from the stream */
 
 	while (!is->IsEOF()) {
-		Tag *tag = is->ReadTag();
-		if (tag != NULL) {
-			fprintf(stderr, "Received a tag:\n");
-			tag_save(stderr, *tag);
-			delete tag;
+		{
+			auto tag = is->ReadTag();
+			if (tag) {
+				fprintf(stderr, "Received a tag:\n");
+				tag_save(stderr, *tag);
+			}
 		}
 
 		char buffer[4096];