minishell/src/subst/wildcard_exp.c

/* ************************************************************************** */
/*                                                                            */
/*                                                        :::      ::::::::   */
/*   wildcard_exp.c                                     :+:      :+:    :+:   */
/*                                                    +:+ +:+         +:+     */
/*   By: jguelen <jguelen@student.42.fr>            +#+  +:+       +#+        */
/*                                                +#+#+#+#+#+   +#+           */
/*   Created: 2025/03/20 15:01:38 by jguelen           #+#    #+#             */
/*   Updated: 2025/03/21 18:42:04 by jguelen          ###   ########.fr       */
/*                                                                            */
/* ************************************************************************** */

#include "libft.h"
#include "subst.h"
#include "replace_substr.h"

/******************************************************************************/
/*                                                                            */
/* NOTE: The use of errno and the setting of it was OKed by Alexandru in this */
/* context.                                                                   */
/*                                                                            */
/******************************************************************************/
/*
** Returns a directory stream corresponding to the current directory.
**
*/
static DIR	*open_current_dir(void)
{
	char	*cur_dir_path;
	size_t	size;
	DIR		*dir;

	size = PATH_SIZE_INIT;
	cur_dir_path = malloc(size * sizeof(char));
	if (!cur_dir_path)
		return (NULL);
	while (getcwd(cur_dir_path, size) == NULL)
	{
		if (errno != ERANGE)
			return (NULL);
		free(cur_dir_path);
		size *= 2;
		cur_dir_path = malloc(size * sizeof(char));
		if (!cur_dir_path)
			return (NULL);
	}
	errno = 0;
	dir = opendir(cur_dir_path);
	free(cur_dir_path);
	return (dir);
}

/*
** Adds filename to the end of the wordlist *list by creating a worddesc whose
** word is filename and marker makes filename be considered fully single
** quoted.
** NOTE: In case of error, this function destroys *list in a similar fashion
** as worddesc_create destroys its first parameter in case of failure.
*/
static t_wordlist	*add_file_to_list(t_wordlist **list, char *filename)
{
	t_worddesc	*file_desc;
	char		*copy;
	char		*marker;

	copy = ft_strdup(filename);
	if (!copy)
		return (wordlist_destroy(*list), NULL);
	marker = construct_repeting_char_string('\'', ft_strlen(copy));
	if (!marker)
		return (wordlist_destroy(*list), free(copy), NULL);
	file_desc = worddesc_create(copy, '\0', marker);
	if (!file_desc)
	{
		wordlist_destroy(*list);
		free(marker);
		return (NULL);
	}
	*list = wordlist_push(*list, file_desc);
	return (*list);
}

/*
** A function designed to present all possible * or ? filename expansions
** for the current directory. (? is not asked by the subject).
** Does not take into account any other wildcard and does only search the
** current working directory.
** @PARAM A C compliant character string representing a pattern for a filename.
** @RETURN Returns a wordlist for which each entry corresponds to a filename
** that matches pattern->word if any file matches in the current directory.
** Otherwise return file_pattern itself if nothing matches the perceived
** pattern. This list should be alphabetically sorted.
** Can return NULL only in case of error.
** NOTE: this function never becomes the owner of file_pattern to maintain
** coherency of use.
*/
static t_wordlist	*expand_star_core(t_worddesc *file_pattern)
{
	struct dirent	*new;
	DIR				*current_dir;
	t_wordlist		*file_wordlist;

	current_dir = open_current_dir();
	if (current_dir == NULL)
		return (NULL);
	file_wordlist = NULL;
	errno = 0;
	new = readdir(current_dir);
	while (new)
	{
		if (fits_pattern(new->d_name, file_pattern))
		{
			if (add_file_to_list(&file_wordlist, new->d_name) == NULL)
				return (NULL);
		}
		errno = 0;
		new = readdir(current_dir);
	}
	if (errno)
		return (wordlist_destroy(file_wordlist), NULL);
	if (!file_wordlist)
		file_wordlist = wordlist_independant_create(file_pattern);
	return (wordlist_quicksort_full(file_wordlist));
}

/*
** Returns 1 if and only if filename is recognized by pattern, 0
** otherwise or -1 in case of error.
** Takes only into account the * wildcard or ?, those characters
** NOTE: for a pattern to accept '.' as the first character of a filename
** it must be explicitly matched (only for the first character though).
** Similarly, '/' is never to be matched except if given explicitly as per
** bash requirement. This is a note in case of future expansion as in our case
** here we do not have to deal with that since we concern ourselves only with
** the current working directory.
*/
char	fits_pattern(char *str, t_worddesc *pattern)
{
	char	**pattern_check;
	size_t	str_len;
	size_t	pattern_len;
	size_t	i;
	char	ret;

	if (str && str[0] == '.' && pattern->word[0] != '.')
		return (0);
	pattern_len = ft_strlen(pattern->word);
	str_len = ft_strlen(str);
	pattern_check = ft_calloc(str_len + 1, sizeof(char *));
	if (!pattern_check)
		return (-1);
	i = 0;
	while (i <= str_len)
	{
		pattern_check[i] = ft_calloc(pattern_len + 1, sizeof(char));
		if (!pattern_check[i])
			return (destroy_pattern_check(pattern_check, str_len + 1), -1);
		i++;
	}
	build_pattern_checks(str, pattern, pattern_check);
	ret = pattern_check[str_len][pattern_len];
	destroy_pattern_check(pattern_check, str_len + 1);
	return (ret);
}

/*
** Returns NULL in case of error.
** NOTE: This phase of pre-processing relies partly on processing done before
** it therefore checks more loosely (and quote removal still seems not to be
** done on string comming from a variable expansion) <-----TO RE-CHECK
*/
t_wordlist	*expand_star(t_worddesc *file_pattern)
{
	clean_pattern(file_pattern);
	return (expand_star_core(file_pattern));
}