proplib/prop_parse_du.c

   1 /*
   2  * [root dictionary]
   3  *     [child dictionary]
   4  *         [path]
   5  *         [size]
   6  *         [type]
   7  *     [child dictionary]
   8  *         [path]
   9  *         [size]
  10  *         [type]
  11  *     ...
  12  *
  13  * Compile with:
  14  * gcc prop_parse_du.c -o prop_parse_du -lprop -Wall -W -Wextra -ansi -pedantic
  15  */
  16
  17 #include <err.h>
  18 #include <stdio.h>
  19 #include <stdlib.h>
  20 #include <string.h>
  21 #include <prop/proplib.h>
  22
  23 #define INIT_ROOT_CAPACITY 100    /* root's dict initial capacity */
  24 #define INIT_CHILD_CAPACITY 3     /* child's dict initial capacity */
  25 #define MAX_STR 100
  26 #define MAX_TOKENS 3
  27
  28 /* Resources */
  29 FILE *fp = NULL;
  30 prop_dictionary_t prd = NULL;    /* root dictionary */
  31 prop_dictionary_t pcd = NULL;    /* child dictionary */
  32 prop_string_t ps = NULL;         /* path name */
  33 prop_number_t pn = NULL;         /* size in bytes */
  34
  35 int main(void)
  36 {
  37     char str[MAX_STR];
  38     char *tokens[MAX_TOKENS];    /* for du(1) output parse */
  39     char *last, *p;
  40     int i;
  41
  42     /* Initiate pipe stream to du(1) */
  43     fp = popen("du", "r");
  44     if (fp == NULL)
  45         exit(EXIT_FAILURE);
  46
  47     /* Create root dictionary */
  48     prd = prop_dictionary_create_with_capacity(INIT_ROOT_CAPACITY);
  49     if (prd == NULL)
  50         err(EXIT_FAILURE, "prop_dictionary_create_with_capacity()");
  51
  52     /* Read from stream */
  53     while (fgets(str, MAX_STR, fp) != NULL) {
  54         /* Parse output of du(1) command */
  55         i = 0;
  56         p = strtok_r(str, "\t", &last);
  57         while (p && i < MAX_TOKENS - 1) {
  58             tokens[i++] = p;
  59             p = strtok_r(NULL, "\t", &last);
  60         }
  61         tokens[i] = NULL;
  62
  63         /* Trim '\n' from tokens[1] */
  64         (tokens[1])[strlen(tokens[1]) - 1] = '\0';
  65
  66         /* Create child dictionary */
  67         pcd = prop_dictionary_create_with_capacity(INIT_CHILD_CAPACITY);
  68         if (pcd == NULL)
  69             err(EXIT_FAILURE, "prop_dictionary_create_with_capacity()");
  70
  71         /*
  72          * tokens[0] holds the size in bytes
  73          *
  74          * We use a signed prop_number_t object, so that
  75          * when externalized it will be represented as decimal
  76          * (unsigned numbers are externalized in base-16).
  77          *
  78          * Note: atoi() does not detect errors, but we trust
  79          * du(1) to provide us with valid input. Otherwise,
  80          * we should use strtol(3) or sscanf(3).
  81          */
  82         pn = prop_number_create_integer(atoi(tokens[0]));
  83
  84         /* tokens[1] holds the path */
  85         ps = prop_string_create_cstring(tokens[1]);
  86
  87         /* Add path to child dictionary */
  88         if (prop_dictionary_set(pcd, "path", ps) == FALSE)
  89             err(EXIT_FAILURE, "prop_dictionary_set()");
  90
  91         /* Add size to child dictionary */
  92         if (prop_dictionary_set(pcd, "size in bytes", pn) == FALSE)
  93             err(EXIT_FAILURE, "prop_dictionary_set()");
  94
  95         /* Add child dictionary to root dictionary */
  96         if (prop_dictionary_set(prd, tokens[1], pcd) == FALSE)
  97             err(EXIT_FAILURE, "prop_dictionary_set()");
  98
  99         /* Release `pn' and `ps' */
 100         prop_object_release(pn);
 101         prop_object_release(ps);
 102
 103         /* Release child dictionary */
 104         prop_object_release(pcd);
 105     }
 106
 107     /* Externalize root dictionary to file in XML representation */
 108     if (prop_dictionary_externalize_to_file(prd, "./data.xml") == FALSE)
 109         err(EXIT_FAILURE, "prop_dictionary_externalize_to_file()");
 110
 111     /* Release root dictionary */
 112     prop_object_release(prd);
 113
 114     /* Close pipe stream */
 115     if  (pclose(fp) == -1)
 116         err(EXIT_FAILURE, "pclose()");
 117
 118     return EXIT_SUCCESS;
 119 }