db/update/IO: pass std::string_view to directory_child_is_regular()

src/db/update/UpdateIO.cxx

@@ -66,7 +66,7 @@ DirectoryExists(Storage &storage, const Directory &directory) noexcept
 
 static StorageFileInfo
 GetDirectoryChildInfo(Storage &storage, const Directory &directory,
-		      const char *name_utf8)
+		      std::string_view name_utf8)
 {
 	const auto uri_utf8 = PathTraitsUTF8::Build(directory.GetPath(),
 						    name_utf8);
@@ -75,7 +75,7 @@ GetDirectoryChildInfo(Storage &storage, const Directory &directory,
 
 bool
 directory_child_is_regular(Storage &storage, const Directory &directory,
-			   const char *name_utf8) noexcept
+			   std::string_view name_utf8) noexcept
 try {
 	return GetDirectoryChildInfo(storage, directory, name_utf8)
 		.IsRegular();

src/db/update/UpdateIO.hxx

@@ -22,6 +22,8 @@
 
 #include "util/Compiler.h"
 
+#include <string_view>
+
 struct Directory;
 struct StorageFileInfo;
 class Storage;
@@ -48,7 +50,7 @@ DirectoryExists(Storage &storage, const Directory &directory) noexcept;
 gcc_pure
 bool
 directory_child_is_regular(Storage &storage, const Directory &directory,
-			   const char *name_utf8) noexcept;
+			   std::string_view name_utf8) noexcept;
 
 /**
  * Checks if the given permissions on the mapped file are given.

src/db/update/Walk.cxx

@@ -103,7 +103,7 @@ UpdateWalk::PurgeDeletedFromDirectory(Directory &directory) noexcept
 
 	directory.ForEachSongSafe([&](Song &song){
 			if (!directory_child_is_regular(storage, directory,
-							song.filename.c_str())) {
+							song.filename)) {
 				editor.LockDeleteSong(directory, &song);
 
 				modified = true;
@@ -113,8 +113,7 @@ UpdateWalk::PurgeDeletedFromDirectory(Directory &directory) noexcept
 	for (auto i = directory.playlists.begin(),
 		     end = directory.playlists.end();
 	     i != end;) {
-		if (!directory_child_is_regular(storage, directory,
-						i->name.c_str())) {
+		if (!directory_child_is_regular(storage, directory, i->name)) {
 			const ScopeDatabaseLock protect;
 			i = directory.playlists.erase(i);
 		} else