searchPath.c

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/**
 * @file searchPath.c
 * @brief Implementation of search path management and file locating functions.
 *
 * @copyright 
 *   - (c) 2002 The University of Chicago, as Operator of Argonne National Laboratory.
 *   - (c) 2002 The Regents of the University of California, as Operator of Los Alamos National Laboratory.
 *
 * @license 
 * This file is distributed under the terms of the Software License Agreement
 * found in the file LICENSE included with this distribution.
 *
 * @author H. Shang, M. Borland, R. Soliday
 */
 
#include "mdb.h"
 
static MDB_THREAD_LOCK search_path_lock = MDB_THREAD_LOCK_INITIALIZER;
static char *search_path = NULL;
/**
 * @brief Sets the search path for file lookup.
 *
 * This function updates the global `search_path` variable. If a new input path is provided,
 * it copies the input string to `search_path`, freeing any previously allocated memory.
 * If the input is `NULL`, `search_path` is set to `NULL`.
 *
 * @param input The new search path to set. If `NULL`, the search path is cleared.
 */
void setSearchPath(char *input) {
  char *new_search_path = NULL;
  char *old_search_path;
 
  if (input)
    cp_str(&new_search_path, input);
 
  mdb_thread_lock(&search_path_lock);
  old_search_path = search_path;
  search_path = new_search_path;
  mdb_thread_unlock(&search_path_lock);
 
  if (old_search_path)
    free(old_search_path);
}
 
/**
 * @brief Finds a file within the configured search path.
 *
 * This function searches for the specified `filename` in each directory listed in the
 * `search_path`. If the `filename` includes SDDS tags (indicated by '=' and '+'),
 * the tags are processed and appended to the found file path.
 *
 * @param filename The name of the file to locate. It may include SDDS tags in the format
 *                 `<filename>=<x>+<y>`.
 * @return A dynamically allocated string containing the path to the found file with tags,
 *         or `NULL` if the file is not found.
 */
char *findFileInSearchPath(const char *filename) {
    char *pathList = NULL;
 
    if (!filename || !strlen(filename))
        return NULL;
 
    /* Work on a modifiable copy of filename */
    char *localFilename = strdup(filename);
    if (!localFilename)
        return NULL;
 
    char *sddsTags = NULL;
    /* Look for '=' in the copy */
    if ((sddsTags = strchr(localFilename, '='))) {
        *sddsTags = '\0';
        sddsTags++;
    }
 
    char *result = NULL;
    mdb_thread_lock(&search_path_lock);
    if (search_path && strlen(search_path))
        cp_str(&pathList, search_path);
    mdb_thread_unlock(&search_path_lock);
 
    if (pathList) {
        char *path;
        while ((path = get_token(pathList))) {
            size_t needed = strlen(localFilename) + strlen(path) + 2 +
                            (sddsTags ? strlen(sddsTags) + 2 : 0);
            char *tmpName = malloc(needed);
            sprintf(tmpName, "%s/%s", path, localFilename);
            free(path);
            if (fexists(tmpName)) {
                if (sddsTags) {
                    strcat(tmpName, "=");
                    strcat(tmpName, sddsTags);
                }
                cp_str(&result, tmpName);
                free(tmpName);
                free(pathList);
                free(localFilename);
                return result;
            }
            free(tmpName);
        }
        free(pathList);
    }
    if (fexists(localFilename)) {
        result = strdup(filename);
        free(localFilename);
        return result;
    }
    free(localFilename);
    return NULL;
}