util/DeleteDisposer: new utility class

src/db/plugins/simple/Directory.cxx

@@ -31,6 +31,7 @@
 #include "lib/icu/Collate.hxx"
 #include "fs/Traits.hxx"
 #include "util/Alloc.hxx"
+#include "util/DeleteDisposer.hxx"
 #include "util/Error.hxx"
 
 #include <assert.h>
@@ -51,7 +52,7 @@ Directory::~Directory()
 	delete mounted_database;
 
 	songs.clear_and_dispose(Song::Disposer());
-	children.clear_and_dispose(Disposer());
+	children.clear_and_dispose(DeleteDisposer());
 }
 
 void
@@ -61,7 +62,7 @@ Directory::Delete()
 	assert(parent != nullptr);
 
 	parent->children.erase_and_dispose(parent->children.iterator_to(*this),
-					   Disposer());
+					   DeleteDisposer());
 }
 
 const char *
@@ -110,7 +111,8 @@ Directory::PruneEmpty()
 		child->PruneEmpty();
 
 		if (child->IsEmpty())
-			child = children.erase_and_dispose(child, Disposer());
+			child = children.erase_and_dispose(child,
+							   DeleteDisposer());
 		else
 			++child;
 	}

src/db/plugins/simple/Directory.hxx

@@ -53,12 +53,6 @@ struct Directory {
 	typedef boost::intrusive::link_mode<link_mode> LinkMode;
 	typedef boost::intrusive::list_member_hook<LinkMode> Hook;
 
-	struct Disposer {
-		void operator()(Directory *directory) const {
-			delete directory;
-		}
-	};
-
 	/**
 	 * Pointers to the siblings of this directory within the
 	 * parent directory.  It is unused (undefined) in the root