support.c

   1 /*
   2
   3     Ann Hell Ex Machina - Music Software
   4     Copyright (C) 2003/2006 Angel Ortega <angel@triptico.com>
   5
   6     support.c - Miscellaneous support functions
   7
   8     This program is free software; you can redistribute it and/or
   9     modify it under the terms of the GNU General Public License
  10     as published by the Free Software Foundation; either version 2
  11     of the License, or (at your option) any later version.
  12
  13     This program is distributed in the hope that it will be useful,
  14     but WITHOUT ANY WARRANTY; without even the implied warranty of
  15     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16     GNU General Public License for more details.
  17
  18     You should have received a copy of the GNU General Public License
  19     along with this program; if not, write to the Free Software
  20     Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
  21
  22     http://www.triptico.com
  23
  24 */
  25
  26 #include "config.h"
  27
  28 #include <stdio.h>
  29 #include <string.h>
  30 #include <stdlib.h>
  31
  32 #include "annhell.h"
  33
  34 /*******************
  35         Data
  36 ********************/
  37
  38 static char ** library_path = NULL;
  39 static int n_library_paths = 0;
  40
  41 static char located_file[2048];
  42
  43 /* global verbose flag */
  44 int verbose = 1;
  45
  46 /* global tracing flag */
  47 int trace = 0;
  48
  49 /*******************
  50         Code
  51 ********************/
  52
  53 /**
  54  * add_to_library_path - Adds a directory path to the search path
  55  * @path: the directory path
  56  * @strip: flag to strip the upper level
  57  *
  58  * Adds @path to the list of searchable paths for path_fopen(),
  59  * optionally stripping the upper level if @strip is set.
  60  * The last part of the path is stripped before being stored,
  61  * and duplication is avoided.
  62  */
  63 void add_to_library_path(char * path, int strip)
  64 {
  65         int n;
  66         char * ptr;
  67
  68         /* if path starts with ~, pre-prend $HOME */
  69         if(*path == '~')
  70         {
  71                 char * new;
  72                 char * home;
  73
  74                 if((home = getenv("HOME")) == NULL)
  75                         return;
  76
  77                 if((new = malloc(strlen(home) + strlen(path) + 2)) == NULL)
  78                         return;
  79
  80                 strcpy(new, home);
  81                 strcat(new, "/");
  82                 strcat(new, path + 1);
  83
  84                 path = new;
  85         }
  86         else
  87         {
  88                 /* just duplicate */
  89                 path = strdup(path);
  90         }
  91
  92         /* if no directory path remains, abort */
  93         if((ptr = strrchr(path, '/')) == NULL)
  94         {
  95                 free(path);
  96                 return;
  97         }
  98
  99         /* strip the filename part */
 100         if(strip) *ptr = '\0';
 101
 102         /* now try to find if that path is already stored */
 103         for(n = 0;n < n_library_paths;n++)
 104         {
 105                 if(strcmp(path, library_path[n]) == 0)
 106                 {
 107                         /* found; free and return */
 108                         free(path);
 109                         return;
 110                 }
 111         }
 112
 113         /* add room for the new path */
 114         n_library_paths++;
 115         library_path = (char **)realloc(library_path,
 116                 n_library_paths * sizeof(char *));
 117
 118         /* store */
 119         library_path[n_library_paths - 1] = path;
 120 }
 121
 122
 123 /**
 124  * path_fopen - Opens a file, optionally searching in a path list
 125  * @filename: the file name
 126  * @mode: the file mode
 127  *
 128  * Opens a file. If the file is found as is, it's opened;
 129  * otherwise, the full list of directory paths maintained by
 130  * add_to_library_path() is searched until it's found or the
 131  * end of the list is reached. Whenever a file
 132  * is successfully opened, its path is also stored.
 133  */
 134 FILE * path_fopen(char * filename, char * mode)
 135 {
 136         int n;
 137         FILE * f = NULL;
 138
 139         /* try first here */
 140         if((f = fopen(filename, mode)) != NULL)
 141         {
 142                 strncpy(located_file, filename, sizeof(located_file));
 143                 located_file[sizeof(located_file) - 1] = '\0';
 144
 145                 add_to_library_path(filename, 1);
 146                 return(f);
 147         }
 148
 149         /* couldn't open; try concatenating all stored paths */
 150         for(n = n_library_paths - 1;n >= 0;n--)
 151         {
 152                 snprintf(located_file, sizeof(located_file), "%s/%s",
 153                         library_path[n], filename);
 154                 located_file[sizeof(located_file) - 1] = '\0';
 155
 156                 if((f = fopen(located_file, mode)) != NULL)
 157                 {
 158                         add_to_library_path(located_file, 1);
 159                         break;
 160                 }
 161         }
 162
 163         return(f);
 164 }
 165
 166
 167 /**
 168  * locate_file - Locates a file inside the path
 169  * @filename: the file to be located
 170  *
 171  * Locates a file inside the library path maintained by path_fopen()
 172  * and add_library_path(). If the file is found, a pointer to a static
 173  * buffer containing the real path of the file is returned, or
 174  * NULL otherwise.
 175  */
 176 char * locate_file(char * filename)
 177 {
 178         FILE * f;
 179
 180         if((f = path_fopen(filename, "r")) == NULL)
 181                 return(NULL);
 182
 183         fclose(f);
 184         return(located_file);
 185 }