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 "para.h"
  11 #include "server.cmdline.h"
  12 #include "afh.h"
  13 #include "server.h"
  14 #include "afs_common.h"
  15 #include "error.h"
  16 #include "net.h"
  17 #include "string.h"
  18 #include "random_selector_command_list.h"
  19
  20 extern struct misc_meta_data *mmd;
  21
  22 static unsigned int num_audio_files, audio_file_count;
  23 static char **audio_file_list;
  24
  25 static int count_audio_files(__a_unused const char *dir, __a_unused const char *name)
  26 {
  27         num_audio_files++;
  28         return 1;
  29 }
  30
  31 static int remember_file(const char *dir, const char *name)
  32 {
  33         if (audio_file_count < num_audio_files) {
  34                 audio_file_list[audio_file_count] =
  35                         make_message("%s/%s", dir, name);
  36                 audio_file_count++;
  37         }
  38         return 1;
  39 }
  40
  41 int com_random_info(int fd, __a_unused int argc, __a_unused char * const * const argv)
  42 {
  43         return send_buffer(fd, "Don't use for huge directories as it is "
  44                 "very inefficient in this case.\n");
  45 }
  46
  47 /*
  48  * Load a list of all audio files into memory and chose num of them randomly.
  49  * Called by server to determine next audio file to be streamed.
  50  */
  51 static char **random_get_audio_file_list(unsigned int num)
  52 {
  53         int i, ret;
  54         unsigned int len;
  55         char **ret_list = NULL; /* what we are going to return */
  56
  57         audio_file_list = NULL;
  58         num_audio_files = 0;
  59         /* first run, just count all audio files. dopey */
  60         ret = find_audio_files(conf.random_dir_arg, count_audio_files);
  61         if (ret < 0)
  62                 goto out;
  63         ret = -E_NOTHING_FOUND;
  64         if (!num_audio_files)
  65                 goto out;
  66         /* yeah, that doesn't scale, also dopey */
  67         audio_file_list = para_malloc(num_audio_files * sizeof(char *));
  68         audio_file_count = 0;
  69         /* second run (hot dentry cache, hopefully), fill audio_file_list */
  70         ret = find_audio_files(conf.random_dir_arg, remember_file);
  71         if (ret < 0)
  72                 goto out;
  73         /* careful, files might got deleted underneath */
  74         num_audio_files = audio_file_count; /* can only decrease */
  75         len = PARA_MIN(num, num_audio_files);
  76         ret = -E_NOTHING_FOUND;
  77         if (!len) /* nothing found, return NULL */
  78                 goto out;
  79         /* success, return NULL-terminated list */
  80         ret_list = para_calloc((len + 1) * sizeof(char *));
  81         for (i = 0; i < len; i++) { /* choose randomly */
  82                 int r = (int) ((num_audio_files + 0.0) * (rand()
  83                         / (RAND_MAX + 1.0)));
  84                 ret_list[i] = para_strdup(audio_file_list[r]);
  85         }
  86         ret = 1;
  87 out:
  88         if (audio_file_list) {
  89                 for (i = 0; i < num_audio_files; i++)
  90                         free(audio_file_list[i]);
  91                 free(audio_file_list);
  92         }
  93         if (ret > 0) {
  94         } else
  95                 sprintf(mmd->selector_info, "dbinfo1:%s\n", PARA_STRERROR(-ret));
  96         return ret_list;
  97 }
  98
  99 static void random_update_audio_file(char *audio_file)
 100 {
 101         char *dn = para_dirname(audio_file);
 102         snprintf(mmd->selector_info, MMD_INFO_SIZE - 1,
 103                 "dbinfo1:current dir: %s\n"
 104                 "dbinfo2:random_dir: %s\n"
 105                 "dbinfo3:%d files available\n",
 106                 dn, conf.random_dir_arg, num_audio_files);
 107         free(dn);
 108         mmd->selector_info[MMD_INFO_SIZE - 1] = '\0';
 109 }
 110 static void random_shutdown(void)
 111 {
 112 }
 113
 114 /**
 115  * the init function for the random audio file selector
 116  *
 117  * \param s pointer ro the struct to iniitalize
 118  *
 119  * Init all function pointers of \a s, init the info text and seed the PRNG.
 120  *
 121  * \sa struct audio_file_selector, misc_meta_data::selector_info, mysql.c
 122  */
 123 int random_selector_init(struct audio_file_selector *s)
 124 {
 125         struct timeval now;
 126         unsigned int seed;
 127
 128         PARA_INFO_LOG("%s", "registering random handlers ;)\n");
 129         gettimeofday(&now, NULL);
 130         seed = now.tv_usec;
 131         srand(seed);
 132         s->cmd_list = random_selector_cmds;
 133         s->get_audio_file_list = random_get_audio_file_list;
 134         s->shutdown = random_shutdown;
 135         s->update_audio_file = random_update_audio_file;
 136         snprintf(mmd->selector_info, MMD_INFO_SIZE - 1,
 137                 "dbinfo1: Welcome to the random selector\n"
 138                 "dbinfo2: random_dir: %s\n", conf.random_dir_arg);
 139         mmd->selector_info[MMD_INFO_SIZE - 1] = '\0';
 140         return 1;
 141 }