/* SPDX-License-Identifier: LGPL-2.1-or-later */

#include "sd-bus-protocol.h"

#include "bus-signature.h"

#include "bus-type.h"

static int signature_element_length_internal(

                const char *s,

                bool allow_dict_entry,

                unsigned array_depth,

                unsigned struct_depth,

                size_t *l) {

        int r;

        if (!s)

                return -EINVAL;

        assert(l);

        if (bus_type_is_basic(*s) || *s == SD_BUS_TYPE_VARIANT) {

                *l = 1;

                return 0;

        }

        if (*s == SD_BUS_TYPE_ARRAY) {

                size_t t;

                if (array_depth >= 32)

                        return -EINVAL;

                r = signature_element_length_internal(s + 1, true, array_depth+1, struct_depth, &t);

                if (r < 0)

                        return r;

                *l = t + 1;

                return 0;

        }

        if (*s == SD_BUS_TYPE_STRUCT_BEGIN) {

                const char *p = s + 1;

                if (struct_depth >= 32)

                        return -EINVAL;

                while (*p != SD_BUS_TYPE_STRUCT_END) {

                        size_t t;

                        r = signature_element_length_internal(p, false, array_depth, struct_depth+1, &t);

                        if (r < 0)

                                return r;

                        p += t;

                }

                if (p - s < 2)

                        /* D-Bus spec: Empty structures are not allowed; there

                         * must be at least one type code between the parentheses.

                         */

                        return -EINVAL;

                *l = p - s + 1;

                return 0;

        }

        if (*s == SD_BUS_TYPE_DICT_ENTRY_BEGIN && allow_dict_entry) {

                const char *p = s + 1;

                unsigned n = 0;

                if (struct_depth >= 32)

                        return -EINVAL;

                while (*p != SD_BUS_TYPE_DICT_ENTRY_END) {

                        size_t t;

                        if (n == 0 && !bus_type_is_basic(*p))

                                return -EINVAL;

                        r = signature_element_length_internal(p, false, array_depth, struct_depth+1, &t);

                        if (r < 0)

                                return r;

                        p += t;

                        n++;

                }

                if (n != 2)

                        return -EINVAL;

                *l = p - s + 1;

                return 0;

        }

        return -EINVAL;

}

int signature_element_length(const char *s, size_t *l) {

        return signature_element_length_internal(s, true, 0, 0, l);

}

bool signature_is_single(const char *s, bool allow_dict_entry) {

        int r;

        size_t t;

        if (!s)

                return false;

        r = signature_element_length_internal(s, allow_dict_entry, 0, 0, &t);

        if (r < 0)

                return false;

        return s[t] == 0;

}

bool signature_is_pair(const char *s) {

        if (!s)

                return false;

        if (!bus_type_is_basic(*s))

                return false;

        return signature_is_single(s + 1, false);

}

bool signature_is_valid(const char *s, bool allow_dict_entry) {

        const char *p;

        int r;

        if (!s)

                return false;

        p = s;

        while (*p) {

                size_t t;

                r = signature_element_length_internal(p, allow_dict_entry, 0, 0, &t);

                if (r < 0)

                        return false;

                p += t;

        }

        return p - s <= SD_BUS_MAXIMUM_SIGNATURE_LENGTH;

}