db/simple: create dedicated directory

src/db/plugins/simple/Directory.hxx

@@ -0,0 +1,239 @@
+/*
+ * Copyright (C) 2003-2014 The Music Player Daemon Project
+ * http://www.musicpd.org
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#ifndef MPD_DIRECTORY_HXX
+#define MPD_DIRECTORY_HXX
+
+#include "check.h"
+#include "util/list.h"
+#include "Compiler.h"
+#include "db/Visitor.hxx"
+#include "db/PlaylistVector.hxx"
+
+#include <string>
+
+static constexpr unsigned DEVICE_INARCHIVE = -1;
+static constexpr unsigned DEVICE_CONTAINER = -2;
+
+#define directory_for_each_child(pos, directory) \
+	list_for_each_entry(pos, &(directory).children, siblings)
+
+#define directory_for_each_child_safe(pos, n, directory) \
+	list_for_each_entry_safe(pos, n, &(directory).children, siblings)
+
+#define directory_for_each_song(pos, directory) \
+	list_for_each_entry(pos, &(directory).songs, siblings)
+
+#define directory_for_each_song_safe(pos, n, directory) \
+	list_for_each_entry_safe(pos, n, &(directory).songs, siblings)
+
+struct Song;
+struct db_visitor;
+class SongFilter;
+class Error;
+
+struct Directory {
+	/**
+	 * Pointers to the siblings of this directory within the
+	 * parent directory.  It is unused (undefined) in the root
+	 * directory.
+	 *
+	 * This attribute is protected with the global #db_mutex.
+	 * Read access in the update thread does not need protection.
+	 */
+	struct list_head siblings;
+
+	/**
+	 * A doubly linked list of child directories.
+	 *
+	 * This attribute is protected with the global #db_mutex.
+	 * Read access in the update thread does not need protection.
+	 */
+	struct list_head children;
+
+	/**
+	 * A doubly linked list of songs within this directory.
+	 *
+	 * This attribute is protected with the global #db_mutex.
+	 * Read access in the update thread does not need protection.
+	 */
+	struct list_head songs;
+
+	PlaylistVector playlists;
+
+	Directory *parent;
+	time_t mtime;
+	unsigned inode, device;
+	bool have_stat; /* not needed if ino_t == dev_t == 0 is impossible */
+
+	std::string path;
+
+public:
+	Directory(std::string &&_path_utf8, Directory *_parent);
+	~Directory();
+
+	/**
+	 * Create a new root #Directory object.
+	 */
+	gcc_malloc
+	static Directory *NewRoot() {
+		return new Directory(std::string(), nullptr);
+	}
+
+	/**
+	 * Remove this #Directory object from its parent and free it.  This
+	 * must not be called with the root Directory.
+	 *
+	 * Caller must lock the #db_mutex.
+	 */
+	void Delete();
+
+	/**
+	 * Create a new #Directory object as a child of the given one.
+	 *
+	 * Caller must lock the #db_mutex.
+	 *
+	 * @param name_utf8 the UTF-8 encoded name of the new sub directory
+	 */
+	gcc_malloc
+	Directory *CreateChild(const char *name_utf8);
+
+	/**
+	 * Caller must lock the #db_mutex.
+	 */
+	gcc_pure
+	const Directory *FindChild(const char *name) const;
+
+	gcc_pure
+	Directory *FindChild(const char *name) {
+		const Directory *cthis = this;
+		return const_cast<Directory *>(cthis->FindChild(name));
+	}
+
+	/**
+	 * Look up a sub directory, and create the object if it does not
+	 * exist.
+	 *
+	 * Caller must lock the #db_mutex.
+	 */
+	Directory *MakeChild(const char *name_utf8) {
+		Directory *child = FindChild(name_utf8);
+		if (child == nullptr)
+			child = CreateChild(name_utf8);
+		return child;
+	}
+
+	/**
+	 * Looks up a directory by its relative URI.
+	 *
+	 * @param uri the relative URI
+	 * @return the Directory, or nullptr if none was found
+	 */
+	gcc_pure
+	Directory *LookupDirectory(const char *uri);
+
+	gcc_pure
+	bool IsEmpty() const {
+		return list_empty(&children) &&
+			list_empty(&songs) &&
+			playlists.empty();
+	}
+
+	gcc_pure
+	const char *GetPath() const {
+		return path.c_str();
+	}
+
+	/**
+	 * Returns the base name of the directory.
+	 */
+	gcc_pure
+	const char *GetName() const;
+
+	/**
+	 * Is this the root directory of the music database?
+	 */
+	gcc_pure
+	bool IsRoot() const {
+		return parent == nullptr;
+	}
+
+	/**
+	 * Look up a song in this directory by its name.
+	 *
+	 * Caller must lock the #db_mutex.
+	 */
+	gcc_pure
+	const Song *FindSong(const char *name_utf8) const;
+
+	gcc_pure
+	Song *FindSong(const char *name_utf8) {
+		const Directory *cthis = this;
+		return const_cast<Song *>(cthis->FindSong(name_utf8));
+	}
+
+	/**
+	 * Looks up a song by its relative URI.
+	 *
+	 * Caller must lock the #db_mutex.
+	 *
+	 * @param uri the relative URI
+	 * @return the song, or nullptr if none was found
+	 */
+	gcc_pure
+	Song *LookupSong(const char *uri);
+
+	/**
+	 * Add a song object to this directory.  Its "parent" attribute must
+	 * be set already.
+	 */
+	void AddSong(Song *song);
+
+	/**
+	 * Remove a song object from this directory (which effectively
+	 * invalidates the song object, because the "parent" attribute becomes
+	 * stale), but does not free it.
+	 */
+	void RemoveSong(Song *song);
+
+	/**
+	 * Caller must lock the #db_mutex.
+	 */
+	void PruneEmpty();
+
+	/**
+	 * Sort all directory entries recursively.
+	 *
+	 * Caller must lock the #db_mutex.
+	 */
+	void Sort();
+
+	/**
+	 * Caller must lock #db_mutex.
+	 */
+	bool Walk(bool recursive, const SongFilter *match,
+		  VisitDirectory visit_directory, VisitSong visit_song,
+		  VisitPlaylist visit_playlist,
+		  Error &error) const;
+
+	gcc_pure
+	LightDirectory Export() const;
+};
+
+#endif