Directory: convert to fixed-size struct

Using a variable-size struct with embedded string is not worth the
trouble here.  There are not so many Directory objects.

src/Directory.cxx

@@ -25,7 +25,7 @@
 #include "SongSort.hxx"
 #include "Song.hxx"
 #include "fs/Traits.hxx"
-#include "util/VarSize.hxx"
+#include "util/Alloc.hxx"
 #include "util/Error.hxx"
 
 extern "C" {
@@ -38,23 +38,11 @@ extern "C" {
 #include <string.h>
 #include <stdlib.h>
 
-inline Directory *
-Directory::Allocate(const char *path)
-{
-	assert(path != nullptr);
-
-	return NewVarSize<Directory>(sizeof(Directory::path),
-				     strlen(path) + 1,
-				     path);
-}
-
-Directory::Directory(const char *_path)
-	:mtime(0), have_stat(false)
+Directory::Directory(const char *_path_utf8, Directory *_parent)
+	:parent(_parent), path(_path_utf8)
 {
 	INIT_LIST_HEAD(&children);
 	INIT_LIST_HEAD(&songs);
-
-	strcpy(path, _path);
 }
 
 Directory::~Directory()
@@ -68,25 +56,6 @@ Directory::~Directory()
 		child->Free();
 }
 
-Directory *
-Directory::NewGeneric(const char *path, Directory *parent)
-{
-	assert(path != nullptr);
-	assert((*path == 0) == (parent == nullptr));
-
-	Directory *directory = Allocate(path);
-
-	directory->parent = parent;
-
-	return directory;
-}
-
-void
-Directory::Free()
-{
-	DeleteVarSize(this);
-}
-
 void
 Directory::Delete()
 {
@@ -102,7 +71,7 @@ Directory::GetName() const
 {
 	assert(!IsRoot());
 
-	return PathTraitsUTF8::GetBase(path);
+	return PathTraitsUTF8::GetBase(path.c_str());
 }
 
 Directory *
@@ -123,7 +92,7 @@ Directory::CreateChild(const char *name_utf8)
 		path_utf8 = allocated;
 	}
 
-	Directory *child = NewGeneric(path_utf8, this);
+	Directory *child = new Directory(path_utf8, this);
 	g_free(allocated);
 
 	list_add_tail(&child->siblings, &children);
@@ -264,7 +233,7 @@ directory_cmp(gcc_unused void *priv,
 {
 	const Directory *a = (const Directory *)_a;
 	const Directory *b = (const Directory *)_b;
-	return g_utf8_collate(a->path, b->path);
+	return g_utf8_collate(a->path.c_str(), b->path.c_str());
 }
 
 void

src/Directory.hxx

@@ -26,6 +26,8 @@
 #include "DatabaseVisitor.hxx"
 #include "PlaylistVector.hxx"
 
+#include <string>
+
 #include <sys/types.h>
 
 #define DEVICE_INARCHIVE (dev_t)(-1)
@@ -49,10 +51,6 @@ class SongFilter;
 class Error;
 
 struct Directory {
-	template<class T, typename... Args> friend T *
-	NewVarSize(size_t declared_tail_size, size_t real_tail_size,
-		   Args&&... args);
-
 	/**
 	 * Pointers to the siblings of this directory within the
 	 * parent directory.  It is unused (undefined) in the root
@@ -86,36 +84,28 @@ struct Directory {
 	ino_t inode;
 	dev_t device;
 	bool have_stat; /* not needed if ino_t == dev_t == 0 is impossible */
-	char path[sizeof(long)];
 
-protected:
-	Directory(const char *path);
-
-	gcc_malloc gcc_nonnull_all
-	static Directory *Allocate(const char *path);
+	std::string path;
 
 public:
+	Directory(const char *_path_utf8, Directory *_parent);
 	~Directory();
 
-	/**
-	 * Generic constructor for #Directory object.
-	 */
-	gcc_malloc
-	static Directory *NewGeneric(const char *path_utf8, Directory *parent);
-
 	/**
 	 * Create a new root #Directory object.
 	 */
 	gcc_malloc
 	static Directory *NewRoot() {
-		return NewGeneric("", nullptr);
+		return new Directory("", nullptr);
 	}
 
 	/**
 	 * Free this #Directory object (and the whole object tree within it),
 	 * assuming it was already removed from the parent.
 	 */
-	void Free();
+	void Free() {
+		delete this;
+	}
 
 	/**
 	 * Remove this #Directory object from its parent and free it.  This
@@ -178,7 +168,7 @@ public:
 
 	gcc_pure
 	const char *GetPath() const {
-		return path;
+		return path.c_str();
 	}
 
 	/**