pcache.c

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    if(check_fn != pc->check_fn || data != pc->data)
      pca_remove_marks(pc);
/*
 * Record the new callback locally.
 */
    pc->check_fn = check_fn;
    pc->data = data;
/*
 * Configure cpl_file_completions() to use the same callback to
 * select files of interest.
 */
    cfc_set_check_fn(pc->cfc, check_fn, data);
  };
  return;
}

/*.......................................................................
 * Return a description of the last path-caching error that occurred.
 *
 * Input:
 *  pc     PathCache *   The filename cache that suffered the error.
 * Output:
 *  return      char *   The description of the last error.
 */
const char *pca_last_error(PathCache *pc)
{
  return pc ? pc->errmsg : "NULL PathCache argument";
}

/*.......................................................................
 * Discard all cached filenames.
 *
 * Input:
 *  pc   PathCache *  The cache to be cleared.
 */
static void pca_clear_cache(PathCache *pc)
{
  if(pc) {
/*
 * Return all path-nodes to the freelist.
 */
    _rst_FreeList(pc->node_mem);
    pc->head = pc->tail = NULL;
/*
 * Delete all filename strings.
 */
    rst_CacheMem(pc->abs_mem);
    rst_CacheMem(pc->rel_mem);
  };
  return;
}

/*.......................................................................
 * Build the list of files of interest contained in a given
 * colon-separated list of directories.
 *
 * Input:
 *  pc         PathCache *  The cache in which to store the names of
 *                          the files that are found in the list of
 *                          directories.
 *  path      const char *  A colon-separated list of directory
 *                          paths. Under UNIX, when searching for
 *                          executables, this should be the return
 *                          value of getenv("PATH").
 * Output:
 *  return           int    0 - OK.
 *                          1 - An error occurred. A description of
 *                              the error can be acquired by calling
 *                              pca_last_error(pc).
 */
int pca_scan_path(PathCache *pc, const char *path)
{
  const char *pptr; /* A pointer to the next unprocessed character in path[] */
  PathNode *node;   /* A node in the list of directory paths */
  char **fptr;      /* A pointer into pc->abs_mem->files[] */
/*
 * Check the arguments.
 */
  if(!pc)
    return 1;
/*
 * Clear the outdated contents of the cache.
 */
  pca_clear_cache(pc);
/*
 * If no path list was provided, there is nothing to be added to the
 * cache.
 */
  if(!path)
    return 0;
/*
 * Extract directories from the path list, expanding tilde expressions
 * on the fly into pc->pathname, then add them to the list of path
 * nodes, along with a sorted list of the filenames of interest that
 * the directories hold.
 */
  pptr = path;
  while(*pptr) {
/*
 * Extract the next pathname component into pc->path->name.
 */
    if(pca_extract_dir(pc, pptr, &pptr))
      return 1;
/*
 * Add a new node to the list of paths, containing both the
 * directory name and, if not a relative pathname, the list of
 * files of interest in the directory.
 */
    if(add_PathNode(pc, pc->path->name))
      return 1;
  };
/*
 * The file arrays in each absolute directory node are sections of
 * pc->abs_mem->files[]. Record pointers to the starts of each
 * of these sections in each directory node. Note that this couldn't
 * be done in add_PathNode(), because pc->abs_mem->files[] may
 * get reallocated in subsequent calls to add_PathNode(), thus
 * invalidating any pointers to it.
 */
  fptr = pc->abs_mem->files;
  for(node=pc->head; node; node=node->next) {
    node->files = fptr;
    fptr += node->nfile;
  };
  return 0;
}

/*.......................................................................
 * Extract the next directory path from a colon-separated list of
 * directories, expanding tilde home-directory expressions where needed.
 *
 * Input:
 *  pc      PathCache *   The cache of filenames.
 *  path   const char *   A pointer to the start of the next component
 *                        in the path list.
 * Input/Output:
 *  nextp  const char **  A pointer to the next unprocessed character
 *                        in path[] will be assigned to *nextp.
 * Output:
 *  return        int     0 - OK. The extracted path is in pc->path->name.
 *                        1 - Error. A description of the error will
 *                            have been left in pc->errmsg.
 */
static int pca_extract_dir(PathCache *pc, const char *path, const char **nextp)
{
  const char *pptr;         /* A pointer into path[] */
  const char *sptr;         /* The path following tilde expansion */
  int escaped = 0;          /* True if the last character was a backslash */
/*
 * If there is a tilde expression at the beginning of the specified path,
 * place the corresponding home directory into pc->path. Otherwise
 * just clear pc->path.
 */
  if(pca_expand_tilde(pc, path, strlen(path), 0, &pptr))
    return 1;
/*
 * Keep a record of the current location in the path.
 */
  sptr = pptr;
/*
 * Locate the end of the directory name in the pathname string, stopping
 * when either the end of the string is reached, or an un-escaped colon
 * separator is seen.
 */
  while(*pptr && (escaped || *pptr != ':'))
    escaped = !escaped && *pptr++ == '\\';
/*
 * Append the rest of the directory path to the pathname buffer.
 */
  if(_pn_append_to_path(pc->path, sptr, pptr - sptr, 1) == NULL) {
    strcpy(pc->errmsg, "Insufficient memory to record directory name");
    return 1;
  };
/*
 * To facilitate subsequently appending filenames to the directory
 * path name, make sure that the recorded directory name ends in a
 * directory separator.
 */
  {
    int dirlen = strlen(pc->path->name);
    if(dirlen < FS_DIR_SEP_LEN ||
       strncmp(pc->path->name + dirlen - FS_DIR_SEP_LEN, FS_DIR_SEP,
	       FS_DIR_SEP_LEN) != 0) {
      if(_pn_append_to_path(pc->path, FS_DIR_SEP, FS_DIR_SEP_LEN, 0) == NULL) {
	strcpy(pc->errmsg, "Insufficient memory to record directory name");
	return 1;
      };
    };
  };
/*
 * Skip the separator unless we have reached the end of the path.
 */
  if(*pptr==':')
    pptr++;
/*
 * Return the unprocessed tail of the path-list string.
 */
  *nextp = pptr;
  return 0;
}

/*.......................................................................
 * Read a username, stopping when a directory separator is seen, a colon
 * separator is seen, the end of the string is reached, or the username
 * buffer overflows.
 *
 * Input:
 *  pc   PathCache *   The cache of filenames.
 *  string    char *   The string who's prefix contains the name.
 *  slen       int     The max number of characters to read from string[].
 *  literal    int     If true, treat backslashes as literal characters
 *                     instead of escapes.
 * Input/Output:
 *  nextp     char **  A pointer to the next unprocessed character
 *                     in string[] will be assigned to *nextp.
 * Output:
 *  return     int     0 - OK. The username can be found in pc->usrnam.
 *                     1 - Error. A description of the error message
 *                         can be found in pc->errmsg.
 */
static int pca_read_username(PathCache *pc, const char *string, int slen,
			     int literal, const char **nextp)
{
  int usrlen;         /* The number of characters in pc->usrnam[] */
  const char *sptr;   /* A pointer into string[] */
  int escaped = 0;    /* True if the last character was a backslash */
/*
 * Extract the username.
 */
  for(sptr=string,usrlen=0; usrlen < USR_LEN && (sptr-string) < slen; sptr++) {
/*
 * Stop if the end of the string is reached, or a directory separator
 * or un-escaped colon separator is seen.
 */
    if(!*sptr || strncmp(sptr, FS_DIR_SEP, FS_DIR_SEP_LEN)==0 ||
       (!escaped && *sptr == ':'))
      break;
/*
 * Escape the next character?
 */
    if(!literal && !escaped && *sptr == '\\') {
      escaped = 1;
    } else {
      escaped = 0;
      pc->usrnam[usrlen++] = *sptr;
    };
  };
/*
 * Did the username overflow the buffer?
 */
  if(usrlen >= USR_LEN) {
    strcpy(pc->errmsg, "Username too long");
    return 1;
  };
/*
 * Terminate the string.
 */
  pc->usrnam[usrlen] = '\0';
/*
 * Indicate where processing of the input string should continue.
 */
  *nextp = sptr;
  return 0;
}


/*.......................................................................
 * Create a new CacheMem object.
 *
 * Output:
 *  return  CacheMem *  The new object, or NULL on error.
 */
static CacheMem *new_CacheMem(void)
{
  CacheMem *cm;  /* The object to be returned */
/*
 * Allocate the container.
 */
  cm = (CacheMem *)malloc(sizeof(CacheMem));
  if(!cm) {
    fprintf(stderr, "new_CacheMem: Insufficient memory.\n");
    return NULL;
  };
/*
 * Before attempting any operation that might fail, initialize the
 * container at least up to the point at which it can safely be passed
 * to del_CacheMem().
 */
  cm->sg = NULL;
  cm->files_dim = 0;
  cm->files = NULL;
  cm->nfiles = 0;
/*
 * Allocate a list of string segments for storing filenames.
 */
  cm->sg = _new_StringGroup(_pu_pathname_dim());
  if(!cm->sg)
    return del_CacheMem(cm);
/*
 * Allocate an array of pointers to filenames.
 * This will be extended later if needed.
 */
  cm->files_dim = FILES_BLK_FACT;
  cm->files = (char **) malloc(sizeof(*cm->files) * cm->files_dim);
  if(!cm->files) {
    fprintf(stderr,
        "new_CacheMem: Insufficient memory to allocate array of files.\n");
    return del_CacheMem(cm);
  };
  return cm;
}

/*.......................................................................
 * Delete a CacheMem object.
 *
 * Input:
 *  cm   CacheMem *  The object to be deleted.
 * Output:
 *  return CacheMem *  The deleted object (always NULL).
 */
static CacheMem *del_CacheMem(CacheMem *cm)
{
  if(cm) {
/*
 * Delete the memory that was used to record filename strings.
 */
    cm->sg = _del_StringGroup(cm->sg);
/*
 * Delete the array of pointers to filenames.
 */
    cm->files_dim = 0;
    if(cm->files) {
      free(cm->files);
      cm->files = NULL;
    };
/*
 * Delete the container.
 */
    free(cm);
  };
  return NULL;
}

/*.......................................................................
 * Re-initialize the memory used to allocate filename strings.
 *
 * Input:
 *  cm     CacheMem *  The memory cache to be cleared.
 */
static void rst_CacheMem(CacheMem *cm)
{
  _clr_StringGroup(cm->sg);
  cm->nfiles = 0;
  return;
}

/*.......................................................................
 * Append a new directory node to the list of directories read from the
 * path.
 *
 * Input:
 *  pc        PathCache *  The filename cache.
 *  dirname  const char *  The name of the new directory.
 * Output:
 *  return          int    0 - OK.
 *                         1 - Error.
 */
static int add_PathNode(PathCache *pc, const char *dirname)
{
  PathNode *node;  /* The new directory list node */
  int relative;    /* True if dirname[] is a relative pathname */
/*
 * Have we been passed a relative pathname or an absolute pathname?
 */
  relative = strncmp(dirname, FS_ROOT_DIR, FS_ROOT_DIR_LEN) != 0;
/*
 * If it's an absolute pathname, ignore it if the corresponding
 * directory doesn't exist.
 */
  if(!relative && !_pu_path_is_dir(dirname))
    return 0;
/*
 * Allocate a new list node to record the specifics of the new directory.
 */
  node = (PathNode *) _new_FreeListNode(pc->node_mem);
  if(!node) {
    sprintf(pc->errmsg, "Insufficient memory to cache new directory.");
    return 1;
  };
/*
 * Initialize the node.
 */
  node->next = NULL;
  node->relative = relative;
  node->mem = relative ? pc->rel_mem : pc->abs_mem;
  node->dir = NULL;
  node->nfile = 0;
  node->files = NULL;
/*
 * Make a copy of the directory pathname.
 */
  node->dir = _sg_store_string(pc->abs_mem->sg, dirname, 0);
  if(!node->dir) {
    strcpy(pc->errmsg, "Insufficient memory to store directory name.");
    return 1;
  };
/*
 * Scan absolute directories for files of interest, recording their names
 * in node->mem->sg and appending pointers to these names to the
 * node->mem->files[] array.
 */
  if(!node->relative) {
    int nfile = node->nfile = pca_scan_dir(pc, node->dir, node->mem);
    if(nfile < 1) {  /* No files matched or an error occurred */
      node = (PathNode *) _del_FreeListNode(pc->node_mem, node);
      return nfile < 0;
    };
  };
/*
 * Append the new node to the list.
 */
  if(pc->head) {
    pc->tail->next = node;