src/state_file.c

   1 /*
   2  * Copyright (C) 2003-2010 The Music Player Daemon Project
   3  * http://www.musicpd.org
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License along
  16  * with this program; if not, write to the Free Software Foundation, Inc.,
  17  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  18  */
  19
  20 #include "config.h"
  21 #include "state_file.h"
  22 #include "output_state.h"
  23 #include "playlist.h"
  24 #include "playlist_state.h"
  25 #include "volume.h"
  26 #include "glib_compat.h"
  27
  28 #include <glib.h>
  29 #include <assert.h>
  30 #include <string.h>
  31 #include <errno.h>
  32
  33 #undef G_LOG_DOMAIN
  34 #define G_LOG_DOMAIN "state_file"
  35
  36 static char *state_file_path;
  37
  38 /** the GLib source id for the save timer */
  39 static guint save_state_source_id;
  40
  41 /**
  42  * These version numbers determine whether we need to save the state
  43  * file.  If nothing has changed, we won't let the hard drive spin up.
  44  */
  45 static unsigned prev_volume_version, prev_output_version,
  46         prev_playlist_version;
  47
  48 static void
  49 state_file_write(void)
  50 {
  51         FILE *fp;
  52
  53         assert(state_file_path != NULL);
  54
  55         g_debug("Saving state file %s", state_file_path);
  56
  57         fp = fopen(state_file_path, "w");
  58         if (G_UNLIKELY(!fp)) {
  59                 g_warning("failed to create %s: %s",
  60                           state_file_path, strerror(errno));
  61                 return;
  62         }
  63
  64         save_sw_volume_state(fp);
  65         audio_output_state_save(fp);
  66         playlist_state_save(fp, &g_playlist);
  67
  68         while(fclose(fp) && errno == EINTR) /* nothing */;
  69
  70         prev_volume_version = sw_volume_state_get_hash();
  71         prev_output_version = audio_output_state_get_version();
  72         prev_playlist_version = playlist_state_get_hash(&g_playlist);
  73 }
  74
  75 static void
  76 state_file_read(void)
  77 {
  78         FILE *fp;
  79         char line[1024];
  80         bool success;
  81
  82         assert(state_file_path != NULL);
  83
  84         g_debug("Loading state file %s", state_file_path);
  85
  86         fp = fopen(state_file_path, "r");
  87         if (G_UNLIKELY(!fp)) {
  88                 g_warning("failed to open %s: %s",
  89                           state_file_path, strerror(errno));
  90                 return;
  91         }
  92
  93         while (fgets(line, sizeof(line), fp) != NULL) {
  94                 g_strchomp(line);
  95
  96                 success = read_sw_volume_state(line) ||
  97                         audio_output_state_read(line) ||
  98                         playlist_state_restore(line, fp, &g_playlist);
  99                 if (!success)
 100                         g_warning("Unrecognized line in state file: %s", line);
 101         }
 102
 103         while(fclose(fp) && errno == EINTR) /* nothing */;
 104
 105         prev_volume_version = sw_volume_state_get_hash();
 106         prev_output_version = audio_output_state_get_version();
 107         prev_playlist_version = playlist_state_get_hash(&g_playlist);
 108 }
 109
 110 /**
 111  * This function is called every 5 minutes by the GLib main loop, and
 112  * saves the state file.
 113  */
 114 static gboolean
 115 timer_save_state_file(G_GNUC_UNUSED gpointer data)
 116 {
 117         if (prev_volume_version == sw_volume_state_get_hash() &&
 118             prev_output_version == audio_output_state_get_version() &&
 119             prev_playlist_version == playlist_state_get_hash(&g_playlist))
 120                 /* nothing has changed - don't save the state file,
 121                    don't spin up the hard disk */
 122                 return true;
 123
 124         state_file_write();
 125         return true;
 126 }
 127
 128 void
 129 state_file_init(const char *path)
 130 {
 131         assert(state_file_path == NULL);
 132
 133         if (path == NULL)
 134                 return;
 135
 136         state_file_path = g_strdup(path);
 137         state_file_read();
 138
 139         save_state_source_id = g_timeout_add_seconds(5 * 60,
 140                                                      timer_save_state_file,
 141                                                      NULL);
 142 }
 143
 144 void
 145 state_file_finish(void)
 146 {
 147         if (state_file_path == NULL)
 148                 /* no state file configured, no cleanup required */
 149                 return;
 150
 151         if (save_state_source_id != 0)
 152                 g_source_remove(save_state_source_id);
 153
 154         state_file_write();
 155
 156         g_free(state_file_path);
 157 }