path: root/src/database.c

/* the Music Player Daemon (MPD)
 * Copyright (C) 2003-2007 by Warren Dukes (warren.dukes@gmail.com)
 * Copyright (C) 2008 Max Kellermann <max@duempel.org>
 * This project's homepage is: 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#include "database.h"
#include "directory.h"
#include "song.h"
#include "conf.h"
#include "log.h"
#include "ls.h"
#include "path.h"
#include "stats.h"
#include "utils.h"
#include "dbUtils.h"
#include "update.h"
#include "os_compat.h"
#include "myfprintf.h"

static struct directory *music_root;

static time_t directory_dbModTime;

void db_init(void)
{
	music_root = directory_new(NULL, NULL);
	updateDirectory(music_root);
	stats.numberOfSongs = countSongsIn(NULL);
	stats.dbPlayTime = sumSongTimesIn(NULL);
}

void db_finish(void)
{
	directory_free(music_root);
}

struct directory * db_get_root(void)
{
	assert(music_root != NULL);

	return music_root;
}

struct directory * db_get_directory(const char *name)
{
	if (name == NULL)
		return music_root;

	return directory_get_subdir(music_root, name);
}

struct mpd_song *db_get_song(const char *file)
{
	struct mpd_song *song = NULL;
	struct directory *directory;
	char *dir = NULL;
	char *duplicated = xstrdup(file);
	char *shortname = strrchr(duplicated, '/');

	DEBUG("get song: %s\n", file);

	if (!shortname) {
		shortname = duplicated;
	} else {
		*shortname = '\0';
		++shortname;
		dir = duplicated;
	}

	if (!(directory = db_get_directory(dir)))
		goto out;
	if (!(song = songvec_find(&directory->songs, shortname)))
		goto out;
	assert(song->parent == directory);

out:
	free(duplicated);
	return song;
}

int db_walk(const char *name,
	          int (*forEachSong) (struct mpd_song *, void *),
	          int (*forEachDir) (struct directory *, void *), void *data)
{
	struct directory *directory;

	if ((directory = db_get_directory(name)) == NULL) {
		struct mpd_song *song;
		if ((song = db_get_song(name)) && forEachSong) {
			return forEachSong(song, data);
		}
		return -1;
	}

	return directory_walk(directory, forEachSong, forEachDir,
					 data);
}

static char *db_get_file(void)
{
	ConfigParam *param = parseConfigFilePath(CONF_DB_FILE, 1);

	assert(param);
	assert(param->value);

	return param->value;
}

int db_check(void)
{
	struct stat st;
	char *dbFile = db_get_file();

	/* Check if the file exists */
	if (access(dbFile, F_OK)) {
		/* If the file doesn't exist, we can't check if we can write
		 * it, so we are going to try to get the directory path, and
		 * see if we can write a file in that */
		char dirPath[MPD_PATH_MAX];
		parent_path(dirPath, dbFile);
		if (*dirPath == '\0')
			strcpy(dirPath, "/");

		/* Check that the parent part of the path is a directory */
		if (stat(dirPath, &st) < 0) {
			ERROR("Couldn't stat parent directory of db file "
			      "\"%s\": %s\n", dbFile, strerror(errno));
			return -1;
		}

		if (!S_ISDIR(st.st_mode)) {
			ERROR("Couldn't create db file \"%s\" because the "
			      "parent path is not a directory\n", dbFile);
			return -1;
		}

		/* Check if we can write to the directory */
		if (access(dirPath, R_OK | W_OK)) {
			ERROR("Can't create db file in \"%s\": %s\n", dirPath,
			      strerror(errno));
			return -1;
		}

		return 0;
	}

	/* Path exists, now check if it's a regular file */
	if (stat(dbFile, &st) < 0) {
		ERROR("Couldn't stat db file \"%s\": %s\n", dbFile,
		      strerror(errno));
		return -1;
	}

	if (!S_ISREG(st.st_mode)) {
		ERROR("db file \"%s\" is not a regular file\n", dbFile);
		return -1;
	}

	/* And check that we can write to it */
	if (access(dbFile, R_OK | W_OK)) {
		ERROR("Can't open db file \"%s\" for reading/writing: %s\n",
		      dbFile, strerror(errno));
		return -1;
	}

	return 0;
}

int db_save(void)
{
	int fd;
	char *dbFile = db_get_file();
	struct stat st;

	DEBUG("removing empty directories from DB\n");
	directory_prune_empty(music_root);

	DEBUG("sorting DB\n");

	directory_sort(music_root);

	DEBUG("writing DB\n");

	fd = open(dbFile, O_WRONLY|O_TRUNC|O_CREAT, 0666);
	if (fd < 0) {
		ERROR("unable to write to db file \"%s\": %s\n",
		      dbFile, strerror(errno));
		return -1;
	}

	/*
	 * TODO: block signals when writing the db so we don't get a corrupted
	 * db (or unexpected failures).  fdprintf() needs better error handling
	 */
	fdprintf(fd,
	         DIRECTORY_INFO_BEGIN "\n"
	         DIRECTORY_MPD_VERSION VERSION "\n"
	         DIRECTORY_FS_CHARSET "%s\n"
	         DIRECTORY_INFO_END "\n", getFsCharset());

	if (directory_save(fd, music_root) < 0) {
		ERROR("Failed to write to database file: %s\n",
		      strerror(errno));
		xclose(fd);
		return -1;
	}
	xclose(fd);

	if (stat(dbFile, &st) == 0)
		directory_dbModTime = st.st_mtime;

	return 0;
}

int db_load(void)
{
	FILE *fp = NULL;
	char *dbFile = db_get_file();
	struct stat st;

	if (!music_root)
		music_root = directory_new(NULL, NULL);
	while (!(fp = fopen(dbFile, "r")) && errno == EINTR) ;
	if (fp == NULL) {
		ERROR("unable to open db file \"%s\": %s\n",
		      dbFile, strerror(errno));
		return -1;
	}

	/* get initial info */
	{
		char buffer[100];
		int bufferSize = 100;
		int foundFsCharset = 0;
		int foundVersion = 0;

		if (!myFgets(buffer, bufferSize, fp))
			FATAL("Error reading db, fgets\n");
		if (0 == strcmp(DIRECTORY_INFO_BEGIN, buffer)) {
			while (myFgets(buffer, bufferSize, fp) &&
			       0 != strcmp(DIRECTORY_INFO_END, buffer)) {
				if (!prefixcmp(buffer, DIRECTORY_MPD_VERSION))
				{
					if (foundVersion)
						FATAL("already found version in db\n");
					foundVersion = 1;
				} else if (!prefixcmp(buffer,
				                      DIRECTORY_FS_CHARSET)) {
					char *fsCharset;
					char *tempCharset;

					if (foundFsCharset)
						FATAL("already found fs charset in db\n");

					foundFsCharset = 1;

					fsCharset = &(buffer[strlen(DIRECTORY_FS_CHARSET)]);
					if ((tempCharset = getConfigParamValue(CONF_FS_CHARSET))
					    && strcmp(fsCharset, tempCharset)) {
						WARNING("Using \"%s\" for the "
							"filesystem charset "
							"instead of \"%s\"\n",
							fsCharset, tempCharset);
						WARNING("maybe you need to "
							"recreate the db?\n");
						setFsCharset(fsCharset);
					}
				} else {
					FATAL("directory: unknown line in db info: %s\n",
					     buffer);
				}
			}
		} else {
			ERROR("db info not found in db file\n");
			ERROR("you should recreate the db using --create-db\n");
			while (fclose(fp) && errno == EINTR) ;
			return -1;
		}
	}

	DEBUG("reading DB\n");

	directory_load(fp, music_root);
	while (fclose(fp) && errno == EINTR) ;

	stats.numberOfSongs = countSongsIn(NULL);
	stats.dbPlayTime = sumSongTimesIn(NULL);

	if (stat(dbFile, &st) == 0)
		directory_dbModTime = st.st_mtime;

	return 0;
}

time_t db_get_mtime(void)
{
	return directory_dbModTime;
}