random_selector.c

   1 /*
   2  * Copyright (C) 2004-2007 Andre Noll <maan@systemlinux.org>
   3  *
   4  * Licensed under the GPL v2. For licencing details see COPYING.
   5  */
   6
   7 /** \file random_selector.c An audio file selector which chooses files by random */
   8
   9 #include <sys/time.h> /* gettimeofday */
  10 #include "server.cmdline.h"
  11 #include "server.h"
  12 #include "afs.h"
  13 #include "error.h"
  14 #include "net.h"
  15 #include "string.h"
  16 #include "random_selector_command_list.h"
  17
  18 extern struct misc_meta_data *mmd;
  19
  20 static unsigned int num_audio_files, audio_file_count;
  21 static char **audio_file_list;
  22
  23 static int count_audio_files(__a_unused const char *dir, __a_unused const char *name)
  24 {
  25         num_audio_files++;
  26         return 1;
  27 }
  28
  29 static int remember_file(const char *dir, const char *name)
  30 {
  31         if (audio_file_count < num_audio_files) {
  32                 audio_file_list[audio_file_count] =
  33                         make_message("%s/%s", dir, name);
  34                 audio_file_count++;
  35         }
  36         return 1;
  37 }
  38
  39 int com_random_info(int fd, __a_unused int argc, __a_unused char *argv[])
  40 {
  41         return send_buffer(fd, "Don't use for huge directories as it is "
  42                 "very inefficient in this case.\n");
  43 }
  44
  45 /*
  46  * Load a list of all audio files into memory and chose num of them randomly.
  47  * Called by server to determine next audio file to be streamed.
  48  */
  49 static char **random_get_audio_file_list(unsigned int num)
  50 {
  51         int i, ret;
  52         unsigned int len;
  53         char **ret_list = NULL; /* what we are going to return */
  54
  55         audio_file_list = NULL;
  56         num_audio_files = 0;
  57         /* first run, just count all audio files. dopey */
  58         ret = find_audio_files(conf.random_dir_arg, count_audio_files);
  59         if (ret < 0)
  60                 goto out;
  61         ret = -E_NOTHING_FOUND;
  62         if (!num_audio_files)
  63                 goto out;
  64         /* yeah, that doesn't scale, also dopey */
  65         audio_file_list = para_malloc(num_audio_files * sizeof(char *));
  66         audio_file_count = 0;
  67         /* second run (hot dentry cache, hopefully), fill audio_file_list */
  68         ret = find_audio_files(conf.random_dir_arg, remember_file);
  69         if (ret < 0)
  70                 goto out;
  71         /* careful, files might got deleted underneath */
  72         num_audio_files = audio_file_count; /* can only decrease */
  73         len = PARA_MIN(num, num_audio_files);
  74         ret = -E_NOTHING_FOUND;
  75         if (!len) /* nothing found, return NULL */
  76                 goto out;
  77         /* success, return NULL-terminated list */
  78         ret_list = para_calloc((len + 1) * sizeof(char *));
  79         for (i = 0; i < len; i++) { /* choose randomly */
  80                 int r = (int) ((num_audio_files + 0.0) * (rand()
  81                         / (RAND_MAX + 1.0)));
  82                 ret_list[i] = para_strdup(audio_file_list[r]);
  83         }
  84         ret = 1;
  85 out:
  86         if (audio_file_list) {
  87                 for (i = 0; i < num_audio_files; i++)
  88                         free(audio_file_list[i]);
  89                 free(audio_file_list);
  90         }
  91         if (ret > 0) {
  92         } else
  93                 sprintf(mmd->selector_info, "dbinfo1:%s\n", PARA_STRERROR(-ret));
  94         return ret_list;
  95 }
  96
  97 static void random_update_audio_file(char *audio_file)
  98 {
  99         char *dn = para_dirname(audio_file);
 100         snprintf(mmd->selector_info, MMD_INFO_SIZE - 1,
 101                 "dbinfo1:current dir: %s\n"
 102                 "dbinfo2:random_dir: %s\n"
 103                 "dbinfo3:%d files available\n",
 104                 dn, conf.random_dir_arg, num_audio_files);
 105         free(dn);
 106         mmd->selector_info[MMD_INFO_SIZE - 1] = '\0';
 107 }
 108 static void random_shutdown(void)
 109 {
 110 }
 111
 112 /**
 113  * the init function for the random audio file selector
 114  *
 115  * \param s pointer ro the struct to iniitalize
 116  *
 117  * Init all function pointers of \a s, init the info text and seed the PRNG.
 118  *
 119  * \sa struct audio_file_selector, misc_meta_data::selector_info, mysql.c
 120  */
 121 int random_selector_init(struct audio_file_selector *s)
 122 {
 123         struct timeval now;
 124         unsigned int seed;
 125
 126         PARA_INFO_LOG("%s", "registering random handlers ;)\n");
 127         gettimeofday(&now, NULL);
 128         seed = now.tv_usec;
 129         srand(seed);
 130         s->cmd_list = random_selector_cmds;
 131         s->get_audio_file_list = random_get_audio_file_list;
 132         s->shutdown = random_shutdown;
 133         s->update_audio_file = random_update_audio_file;
 134         snprintf(mmd->selector_info, MMD_INFO_SIZE - 1,
 135                 "dbinfo1: Welcome to the random selector\n"
 136                 "dbinfo2: random_dir: %s\n", conf.random_dir_arg);
 137         mmd->selector_info[MMD_INFO_SIZE - 1] = '\0';
 138         return 1;
 139 }