From ebc006ab529169d3d067231863ab7fc52fd9c49a Mon Sep 17 00:00:00 2001
From: Max Kellermann <max@musicpd.org>
Date: Fri, 6 Jul 2018 16:46:01 +0200
Subject: [PATCH] db/simple: wrap LightSong in Manual<>

Prepare to make LightSong non-assignable.
---
 src/db/plugins/simple/SimpleDatabasePlugin.cxx | 18 ++++++++++--------
 src/db/plugins/simple/SimpleDatabasePlugin.hxx |  3 ++-
 2 files changed, 12 insertions(+), 9 deletions(-)

diff --git a/src/db/plugins/simple/SimpleDatabasePlugin.cxx b/src/db/plugins/simple/SimpleDatabasePlugin.cxx
index 772b4d826..6ea2bf9bd 100644
--- a/src/db/plugins/simple/SimpleDatabasePlugin.cxx
+++ b/src/db/plugins/simple/SimpleDatabasePlugin.cxx
@@ -237,30 +237,32 @@ SimpleDatabase::GetSong(const char *uri) const
 		throw DatabaseError(DatabaseErrorCode::NOT_FOUND,
 				    "No such song");
 
-	light_song = song->Export();
+	light_song.Construct(song->Export());
 
 #ifndef NDEBUG
 	++borrowed_song_count;
 #endif
 
-	return &light_song;
+	return &light_song.Get();
 }
 
 void
 SimpleDatabase::ReturnSong(gcc_unused const LightSong *song) const
 {
 	assert(song != nullptr);
-	assert(song == &light_song || song == prefixed_light_song);
-
-	delete prefixed_light_song;
-	prefixed_light_song = nullptr;
+	assert(song == &light_song.Get() || song == prefixed_light_song);
 
+	if (prefixed_light_song != nullptr) {
+		delete prefixed_light_song;
+		prefixed_light_song = nullptr;
+	} else {
 #ifndef NDEBUG
-	if (song == &light_song) {
 		assert(borrowed_song_count > 0);
 		--borrowed_song_count;
-	}
 #endif
+
+		light_song.Destruct();
+	}
 }
 
 void
diff --git a/src/db/plugins/simple/SimpleDatabasePlugin.hxx b/src/db/plugins/simple/SimpleDatabasePlugin.hxx
index c18b580eb..4d167eabf 100644
--- a/src/db/plugins/simple/SimpleDatabasePlugin.hxx
+++ b/src/db/plugins/simple/SimpleDatabasePlugin.hxx
@@ -24,6 +24,7 @@
 #include "db/Interface.hxx"
 #include "fs/AllocatedPath.hxx"
 #include "db/LightSong.hxx"
+#include "util/Manual.hxx"
 #include "Compiler.h"
 
 #include <cassert>
@@ -61,7 +62,7 @@ class SimpleDatabase : public Database {
 	/**
 	 * A buffer for GetSong().
 	 */
-	mutable LightSong light_song;
+	mutable Manual<LightSong> light_song;
 
 #ifndef NDEBUG
 	mutable unsigned borrowed_song_count;