• Max Kellermann's avatar
    db/simple: mount points · e9a85aa4
    Max Kellermann authored
    A SimpleDatabase instance can now "mount" other Database instances at
    certain locations.  This is used to use a new SimpleDatabase instance
    for each storage mount (issued with the "mount" protocol command).
    Each such instance has its own database file, stored in the directory
    that is specified with the "cache_directory" option.
    e9a85aa4
Mount.cxx 2.73 KB
/*
 * 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.
 */

#include "config.h"
#include "Mount.hxx"
#include "PrefixedLightSong.hxx"
#include "db/Selection.hxx"
#include "db/LightDirectory.hxx"
#include "db/LightSong.hxx"
#include "db/Interface.hxx"
#include "fs/Traits.hxx"
#include "util/Error.hxx"

#include <string>

struct PrefixedLightDirectory : LightDirectory {
	std::string buffer;

	PrefixedLightDirectory(const LightDirectory &directory,
			       const char *base)
		:LightDirectory(directory),
		 buffer(IsRoot()
			? std::string(base)
			: PathTraitsUTF8::Build(base, uri)) {
		uri = buffer.c_str();
	}
};

static bool
PrefixVisitDirectory(const char *base, const VisitDirectory &visit_directory,
		     const LightDirectory &directory, Error &error)
{
	return visit_directory(PrefixedLightDirectory(directory, base), error);
}

static bool
PrefixVisitSong(const char *base, const VisitSong &visit_song,
		const LightSong &song, Error &error)
{
	return visit_song(PrefixedLightSong(song, base), error);
}

static bool
PrefixVisitPlaylist(const char *base, const VisitPlaylist &visit_playlist,
		    const PlaylistInfo &playlist,
		    const LightDirectory &directory,
		    Error &error)
{
	return visit_playlist(playlist,
			      PrefixedLightDirectory(directory, base),
			      error);
}

bool
WalkMount(const char *base, const Database &db,
	  bool recursive, const SongFilter *filter,
	  const VisitDirectory &visit_directory, const VisitSong &visit_song,
	  const VisitPlaylist &visit_playlist,
	  Error &error)
{
	using namespace std::placeholders;

	VisitDirectory vd;
	if (visit_directory)
		vd = std::bind(PrefixVisitDirectory,
			       base, std::ref(visit_directory), _1, _2);

	VisitSong vs;
	if (visit_song)
		vs = std::bind(PrefixVisitSong,
			       base, std::ref(visit_song), _1, _2);

	VisitPlaylist vp;
	if (visit_playlist)
		vp = std::bind(PrefixVisitPlaylist,
			       base, std::ref(visit_playlist), _1, _2, _3);

	return db.Visit(DatabaseSelection("", recursive, filter),
			vd, vs, vp, error);
}