MusicChunk, player/Thread: use std::unique_ptr<Tag>

src/MusicChunk.cxx

@@ -24,10 +24,8 @@
 
 #include <assert.h>
 
-MusicChunk::~MusicChunk()
-{
-	delete tag;
-}
+MusicChunk::MusicChunk() noexcept = default;
+MusicChunk::~MusicChunk() noexcept = default;
 
 #ifndef NDEBUG
 bool

src/MusicChunk.hxx

@@ -28,6 +28,8 @@
 #include "AudioFormat.hxx"
 #endif
 
+#include <memory>
+
 #include <stdint.h>
 #include <stddef.h>
 
@@ -67,11 +69,9 @@ struct MusicChunk {
 
 	/**
 	 * An optional tag associated with this chunk (and the
-	 * following chunks); appears at song boundaries.  The tag
-	 * object is owned by this chunk, and must be freed when this
-	 * chunk is deinitialized.
+	 * following chunks); appears at song boundaries.
 	 */
-	Tag *tag = nullptr;
+	std::unique_ptr<Tag> tag;
 
 	/**
 	 * Replay gain information associated with this chunk.
@@ -101,12 +101,10 @@ struct MusicChunk {
 	AudioFormat audio_format;
 #endif
 
-	MusicChunk() = default;
+	MusicChunk() noexcept;
+	~MusicChunk() noexcept;
 
 	MusicChunk(const MusicChunk &) = delete;
-
-	~MusicChunk();
-
 	MusicChunk &operator=(const MusicChunk &) = delete;
 
 	bool IsEmpty() const {

src/decoder/Bridge.cxx

@@ -215,7 +215,7 @@ DecoderBridge::DoSendTag(const Tag &tag)
 		return dc.command;
 	}
 
-	chunk->tag = new Tag(tag);
+	chunk->tag = std::make_unique<Tag>(tag);
 	return DecoderCommand::NONE;
 }
 

src/output/Source.cxx

@@ -222,7 +222,7 @@ AudioOutputSource::Fill(Mutex &mutex)
 	if (current_chunk == nullptr)
 		return false;
 
-	pending_tag = current_chunk->tag;
+	pending_tag = current_chunk->tag.get();
 
 	try {
 		/* release the mutex while the filter runs, because

src/player/Thread.cxx

@@ -131,7 +131,7 @@ class Player {
 	 * postponed, and sent to the output thread when the new song
 	 * really begins.
 	 */
-	Tag *cross_fade_tag = nullptr;
+	std::unique_ptr<Tag> cross_fade_tag;
 
 	/**
 	 * The current audio format for the audio outputs.
@@ -837,10 +837,8 @@ Player::PlayNextChunk() noexcept
 			/* don't send the tags of the new song (which
 			   is being faded in) yet; postpone it until
 			   the current song is faded out */
-			cross_fade_tag =
-				Tag::MergeReplace(cross_fade_tag,
-						  other_chunk->tag);
-			other_chunk->tag = nullptr;
+			cross_fade_tag = Tag::Merge(std::move(cross_fade_tag),
+						    std::move(other_chunk->tag));
 
 			if (pc.cross_fade.mixramp_delay <= 0) {
 				chunk->mix_ratio = ((float)cross_fade_position)
@@ -889,7 +887,8 @@ Player::PlayNextChunk() noexcept
 	/* insert the postponed tag if cross-fading is finished */
 
 	if (xfade_state != CrossFadeState::ACTIVE && cross_fade_tag != nullptr) {
-		chunk->tag = Tag::MergeReplace(chunk->tag, cross_fade_tag);
+		chunk->tag = Tag::Merge(std::move(chunk->tag),
+					std::move(cross_fade_tag));
 		cross_fade_tag = nullptr;
 	}
 
@@ -1114,7 +1113,7 @@ Player::Run() noexcept
 
 	ClearAndDeletePipe();
 
-	delete cross_fade_tag;
+	cross_fade_tag.reset();
 
 	if (song != nullptr) {
 		FormatDefault(player_domain, "played \"%s\"", song->GetURI());

src/tag/Tag.cxx

@@ -63,8 +63,8 @@ Tag::Merge(const Tag &base, const Tag &add) noexcept
 	return builder.CommitNew();
 }
 
-Tag *
-Tag::MergeReplace(Tag *base, Tag *add)
+std::unique_ptr<Tag>
+Tag::Merge(std::unique_ptr<Tag> base, std::unique_ptr<Tag> add)
 {
 	if (add == nullptr)
 		return base;
@@ -72,11 +72,7 @@ Tag::MergeReplace(Tag *base, Tag *add)
 	if (base == nullptr)
 		return add;
 
-	Tag *tag = Merge(*base, *add).release();
-	delete base;
-	delete add;
-
-	return tag;
+	return Merge(*base, *add);
 }
 
 const char *

src/tag/Tag.hxx

@@ -126,8 +126,8 @@ struct Tag {
 	 *
 	 * @return a newly allocated tag
 	 */
-	gcc_malloc gcc_returns_nonnull
-	static Tag *MergeReplace(Tag *base, Tag *add);
+	static std::unique_ptr<Tag> Merge(std::unique_ptr<Tag> base,
+					  std::unique_ptr<Tag> add);
 
 	/**
 	 * Returns the first value of the specified tag type, or