/*
 * argvsplit.c
 * argv_split() routine
 *
 * Copyright (c) 2012, 2017 pkgconf authors (see AUTHORS).
 *
 * Permission to use, copy, modify, and/or distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * This software is provided 'as is' and without any warranty, express or
 * implied.  In no event shall the authors be liable for any damages arising
 * from the use of this software.
 */

#include <libpkgconf/stdinc.h>
#include <libpkgconf/libpkgconf.h>

/*
 * !doc
 *
 * libpkgconf `argvsplit` module
 * =============================
 *
 * This is a lowlevel module which provides parsing of strings into argument vectors,
 * similar to what a shell would do.
 */

/*
 * !doc
 *
 * .. c:function:: void pkgconf_argv_free(char **argv)
 *
 *    Frees an argument vector.
 *
 *    :param char** argv: The argument vector to free.
 *    :return: nothing
 */
void
pkgconf_argv_free(char **argv)
{
        free(argv[0]);
        free(argv);
}

/*
 * !doc
 *
 * .. c:function:: int pkgconf_argv_split(const char *src, int *argc, char ***argv)
 *
 *    Splits a string into an argument vector.
 *
 *    :param char*   src: The string to split.
 *    :param int*    argc: A pointer to an integer to store the argument count.
 *    :param char*** argv: A pointer to a pointer for an argument vector.
 *    :return: 0 on success, -1 on error.
 *    :rtype: int
 */
int
pkgconf_argv_split(const char *src, int *argc, char ***argv)
{
        char *buf = malloc(strlen(src) + 1);
        const char *src_iter;
        char *dst_iter;
        int argc_count = 0;
        int argv_size = 5;
        char quote = 0;
        bool escaped = false;

        src_iter = src;
        dst_iter = buf;

        memset(buf, 0, strlen(src) + 1);

        *argv = calloc(argv_size, sizeof (void *));
        (*argv)[argc_count] = dst_iter;

        while (*src_iter)
        {
                if (escaped)
                {
                        /* POSIX: only \CHAR is special inside a double quote if CHAR is {$, `, ", \, newline}. */
                        if (quote == '"')
                        {
                                if (!(*src_iter == '$' || *src_iter == '`' || *src_iter == '"' || *src_iter == '\\'))
                                        *dst_iter++ = '\\';

                                *dst_iter++ = *src_iter;
                        }
                        else
                        {
                                *dst_iter++ = *src_iter;
                        }

                        escaped = false;
                }
                else if (quote)
                {
                        if (*src_iter == quote)
                                quote = 0;
                        else if (*src_iter == '\\' && quote != '\'')
                                escaped = true;
                        else
                                *dst_iter++ = *src_iter;
                }
                else if (isspace((unsigned char)*src_iter))
                {
                        if ((*argv)[argc_count] != NULL)
                        {
                                argc_count++, dst_iter++;

                                if (argc_count == argv_size)
                                {
                                        argv_size += 5;
                                        *argv = realloc(*argv, sizeof(void *) * argv_size);
                                }

                                (*argv)[argc_count] = dst_iter;
                        }
                }
                else switch(*src_iter)
                {
                        case '\\':
                                escaped = true;
                                break;

                        case '\"':
                        case '\'':
                                quote = *src_iter;
                                break;

                        default:
                                *dst_iter++ = *src_iter;
                                break;
                }

                src_iter++;
        }

        if (escaped || quote)
        {
                free(*argv);
                free(buf);
                return -1;
        }

        if (strlen((*argv)[argc_count]))
        {
                argc_count++;
        }

        *argc = argc_count;
        return 0;
}