xmpp-rs/src/macros.rs

// Copyright (c) 2017-2018 Emmanuel Gil Peyrot <linkmauve@linkmauve.fr>
//
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
// file, You can obtain one at http://mozilla.org/MPL/2.0/.

macro_rules! get_attr {
    ($elem:ident, $attr:tt, $type:tt) => (
        get_attr!($elem, $attr, $type, value, value.parse()?)
    );
    ($elem:ident, $attr:tt, optional_empty, $value:ident, $func:expr) => (
        match $elem.attr($attr) {
            Some("") => None,
            Some($value) => Some($func),
            None => None,
        }
    );
    ($elem:ident, $attr:tt, optional, $value:ident, $func:expr) => (
        match $elem.attr($attr) {
            Some($value) => Some($func),
            None => None,
        }
    );
    ($elem:ident, $attr:tt, required, $value:ident, $func:expr) => (
        match $elem.attr($attr) {
            Some($value) => $func,
            None => return Err(crate::error::Error::ParseError(concat!("Required attribute '", $attr, "' missing."))),
        }
    );
    ($elem:ident, $attr:tt, default, $value:ident, $func:expr) => (
        match $elem.attr($attr) {
            Some($value) => $func,
            None => ::std::default::Default::default(),
        }
    );
}

macro_rules! generate_attribute {
    ($(#[$meta:meta])* $elem:ident, $name:tt, {$($(#[$a_meta:meta])* $a:ident => $b:tt),+,}) => (
        generate_attribute!($(#[$meta])* $elem, $name, {$($(#[$a_meta])* $a => $b),+});
    );
    ($(#[$meta:meta])* $elem:ident, $name:tt, {$($(#[$a_meta:meta])* $a:ident => $b:tt),+,}, Default = $default:ident) => (
        generate_attribute!($(#[$meta])* $elem, $name, {$($(#[$a_meta])* $a => $b),+}, Default = $default);
    );
    ($(#[$meta:meta])* $elem:ident, $name:tt, {$($(#[$a_meta:meta])* $a:ident => $b:tt),+}) => (
        $(#[$meta])*
        #[derive(Debug, Clone, PartialEq)]
        pub enum $elem {
            $(
                $(#[$a_meta])*
                $a
            ),+
        }
        impl ::std::str::FromStr for $elem {
            type Err = crate::error::Error;
            fn from_str(s: &str) -> Result<$elem, crate::error::Error> {
                Ok(match s {
                    $($b => $elem::$a),+,
                    _ => return Err(crate::error::Error::ParseError(concat!("Unknown value for '", $name, "' attribute."))),
                })
            }
        }
        impl ::minidom::IntoAttributeValue for $elem {
            fn into_attribute_value(self) -> Option<String> {
                Some(String::from(match self {
                    $($elem::$a => $b),+
                }))
            }
        }
    );
    ($(#[$meta:meta])* $elem:ident, $name:tt, {$($(#[$a_meta:meta])* $a:ident => $b:tt),+}, Default = $default:ident) => (
        $(#[$meta])*
        #[derive(Debug, Clone, PartialEq)]
        pub enum $elem {
            $(
                $(#[$a_meta])*
                $a
            ),+
        }
        impl ::std::str::FromStr for $elem {
            type Err = crate::error::Error;
            fn from_str(s: &str) -> Result<$elem, crate::error::Error> {
                Ok(match s {
                    $($b => $elem::$a),+,
                    _ => return Err(crate::error::Error::ParseError(concat!("Unknown value for '", $name, "' attribute."))),
                })
            }
        }
        impl ::minidom::IntoAttributeValue for $elem {
            #[allow(unreachable_patterns)]
            fn into_attribute_value(self) -> Option<String> {
                Some(String::from(match self {
                    $elem::$default => return None,
                    $($elem::$a => $b),+
                }))
            }
        }
        impl ::std::default::Default for $elem {
            fn default() -> $elem {
                $elem::$default
            }
        }
    );
    ($(#[$meta:meta])* $elem:ident, $name:tt, bool) => (
        $(#[$meta])*
        #[derive(Debug, Clone, PartialEq)]
        pub enum $elem {
            /// True value, represented by either 'true' or '1'.
            True,
            /// False value, represented by either 'false' or '0'.
            False,
        }
        impl ::std::str::FromStr for $elem {
            type Err = crate::error::Error;
            fn from_str(s: &str) -> Result<Self, crate::error::Error> {
                Ok(match s {
                    "true" | "1" => $elem::True,
                    "false" | "0" => $elem::False,
                    _ => return Err(crate::error::Error::ParseError(concat!("Unknown value for '", $name, "' attribute."))),
                })
            }
        }
        impl ::minidom::IntoAttributeValue for $elem {
            fn into_attribute_value(self) -> Option<String> {
                match self {
                    $elem::True => Some(String::from("true")),
                    $elem::False => None
                }
            }
        }
        impl ::std::default::Default for $elem {
            fn default() -> $elem {
                $elem::False
            }
        }
    );
}

macro_rules! generate_element_enum {
    ($(#[$meta:meta])* $elem:ident, $name:tt, $ns:ident, {$($(#[$enum_meta:meta])* $enum:ident => $enum_name:tt),+,}) => (
        generate_element_enum!($(#[$meta])* $elem, $name, $ns, {$($(#[$enum_meta])* $enum => $enum_name),+});
    );
    ($(#[$meta:meta])* $elem:ident, $name:tt, $ns:ident, {$($(#[$enum_meta:meta])* $enum:ident => $enum_name:tt),+}) => (
        $(#[$meta])*
        #[derive(Debug, Clone, PartialEq)]
        pub enum $elem {
            $(
            $(#[$enum_meta])*
            $enum
            ),+
        }
        impl ::try_from::TryFrom<::minidom::Element> for $elem {
            type Err = crate::error::Error;
            fn try_from(elem: ::minidom::Element) -> Result<$elem, crate::error::Error> {
                check_ns_only!(elem, $name, $ns);
                check_no_children!(elem, $name);
                check_no_attributes!(elem, $name);
                Ok(match elem.name() {
                    $($enum_name => $elem::$enum,)+
                    _ => return Err(crate::error::Error::ParseError(concat!("This is not a ", $name, " element."))),
                })
            }
        }
        impl From<$elem> for ::minidom::Element {
            fn from(elem: $elem) -> ::minidom::Element {
                ::minidom::Element::builder(match elem {
                    $($elem::$enum => $enum_name,)+
                }).ns(crate::ns::$ns)
                  .build()
            }
        }
    );
}

macro_rules! generate_attribute_enum {
    ($(#[$meta:meta])* $elem:ident, $name:tt, $ns:ident, $attr:tt, {$($(#[$enum_meta:meta])* $enum:ident => $enum_name:tt),+,}) => (
        generate_attribute_enum!($(#[$meta])* $elem, $name, $ns, $attr, {$($(#[$enum_meta])* $enum => $enum_name),+});
    );
    ($(#[$meta:meta])* $elem:ident, $name:tt, $ns:ident, $attr:tt, {$($(#[$enum_meta:meta])* $enum:ident => $enum_name:tt),+}) => (
        $(#[$meta])*
        #[derive(Debug, Clone, PartialEq)]
        pub enum $elem {
            $(
            $(#[$enum_meta])*
            $enum
            ),+
        }
        impl ::try_from::TryFrom<::minidom::Element> for $elem {
            type Err = crate::error::Error;
            fn try_from(elem: ::minidom::Element) -> Result<$elem, crate::error::Error> {
                check_ns_only!(elem, $name, $ns);
                check_no_children!(elem, $name);
                check_no_unknown_attributes!(elem, $name, [$attr]);
                Ok(match get_attr!(elem, $attr, required) {
                    $($enum_name => $elem::$enum,)+
                    _ => return Err(crate::error::Error::ParseError(concat!("Invalid ", $name, " ", $attr, " value."))),
                })
            }
        }
        impl From<$elem> for ::minidom::Element {
            fn from(elem: $elem) -> ::minidom::Element {
                ::minidom::Element::builder($name)
                        .ns(crate::ns::$ns)
                        .attr($attr, match elem {
                             $($elem::$enum => $enum_name,)+
                         })
                         .build()
            }
        }
    );
}

macro_rules! check_self {
    ($elem:ident, $name:tt, $ns:ident) => (
        check_self!($elem, $name, $ns, $name);
    );
    ($elem:ident, $name:tt, $ns:ident, $pretty_name:tt) => (
        if !$elem.is($name, crate::ns::$ns) {
            return Err(crate::error::Error::ParseError(concat!("This is not a ", $pretty_name, " element.")));
        }
    );
}

macro_rules! check_ns_only {
    ($elem:ident, $name:tt, $ns:ident) => (
        if !$elem.has_ns(crate::ns::$ns) {
            return Err(crate::error::Error::ParseError(concat!("This is not a ", $name, " element.")));
        }
    );
}

macro_rules! check_no_children {
    ($elem:ident, $name:tt) => (
        for _ in $elem.children() {
            return Err(crate::error::Error::ParseError(concat!("Unknown child in ", $name, " element.")));
        }
    );
}

macro_rules! check_no_attributes {
    ($elem:ident, $name:tt) => (
        for _ in $elem.attrs() {
            return Err(crate::error::Error::ParseError(concat!("Unknown attribute in ", $name, " element.")));
        }
    );
}

macro_rules! check_no_unknown_attributes {
    ($elem:ident, $name:tt, [$($attr:tt),*]) => (
        for (_attr, _) in $elem.attrs() {
            $(
            if _attr == $attr {
                continue;
            }
            )*
            return Err(crate::error::Error::ParseError(concat!("Unknown attribute in ", $name, " element.")));
        }
    );
}

macro_rules! generate_empty_element {
    ($(#[$meta:meta])* $elem:ident, $name:tt, $ns:ident) => (
        $(#[$meta])*
        #[derive(Debug, Clone)]
        pub struct $elem;

        impl ::try_from::TryFrom<::minidom::Element> for $elem {
            type Err = crate::error::Error;

            fn try_from(elem: ::minidom::Element) -> Result<$elem, crate::error::Error> {
                check_self!(elem, $name, $ns);
                check_no_children!(elem, $name);
                check_no_attributes!(elem, $name);
                Ok($elem)
            }
        }

        impl From<$elem> for ::minidom::Element {
            fn from(_: $elem) -> ::minidom::Element {
                ::minidom::Element::builder($name)
                        .ns(crate::ns::$ns)
                        .build()
            }
        }
    );
}

macro_rules! generate_id {
    ($(#[$meta:meta])* $elem:ident) => (
        $(#[$meta])*
        #[derive(Debug, Clone, PartialEq, Eq, Hash)]
        pub struct $elem(pub String);
        impl ::std::str::FromStr for $elem {
            type Err = crate::error::Error;
            fn from_str(s: &str) -> Result<$elem, crate::error::Error> {
                // TODO: add a way to parse that differently when needed.
                Ok($elem(String::from(s)))
            }
        }
        impl ::minidom::IntoAttributeValue for $elem {
            fn into_attribute_value(self) -> Option<String> {
                Some(self.0)
            }
        }
    );
}

macro_rules! generate_elem_id {
    ($(#[$meta:meta])* $elem:ident, $name:tt, $ns:ident) => (
        $(#[$meta])*
        #[derive(Debug, Clone, PartialEq, Eq, Hash)]
        pub struct $elem(pub String);
        impl ::std::str::FromStr for $elem {
            type Err = crate::error::Error;
            fn from_str(s: &str) -> Result<$elem, crate::error::Error> {
                // TODO: add a way to parse that differently when needed.
                Ok($elem(String::from(s)))
            }
        }
        impl ::try_from::TryFrom<::minidom::Element> for $elem {
            type Err = crate::error::Error;
            fn try_from(elem: ::minidom::Element) -> Result<$elem, crate::error::Error> {
                check_self!(elem, $name, $ns);
                check_no_children!(elem, $name);
                check_no_attributes!(elem, $name);
                // TODO: add a way to parse that differently when needed.
                Ok($elem(elem.text()))
            }
        }
        impl From<$elem> for ::minidom::Element {
            fn from(elem: $elem) -> ::minidom::Element {
                ::minidom::Element::builder($name)
                        .ns(crate::ns::$ns)
                        .append(elem.0)
                        .build()
            }
        }
    );
}

macro_rules! start_decl {
    (Vec, $type:ty) => (
        Vec<$type>
    );
    (Option, $type:ty) => (
        Option<$type>
    );
    (Required, $type:ty) => (
        $type
    );
}

macro_rules! start_parse_elem {
    ($temp:ident: Vec) => (
        let mut $temp = Vec::new();
    );
    ($temp:ident: Option) => (
        let mut $temp = None;
    );
    ($temp:ident: Required) => (
        let mut $temp = None;
    );
}

macro_rules! do_parse {
    ($elem:ident, Element) => (
        $elem.clone()
    );
    ($elem:ident, String) => (
        $elem.text()
    );
    ($elem:ident, $constructor:ident) => (
        $constructor::try_from($elem.clone())?
    );
}

macro_rules! do_parse_elem {
    ($temp:ident: Vec = $constructor:ident => $elem:ident, $name:tt, $parent_name:tt) => (
        $temp.push(do_parse!($elem, $constructor));
    );
    ($temp:ident: Option = $constructor:ident => $elem:ident, $name:tt, $parent_name:tt) => (
        if $temp.is_some() {
            return Err(crate::error::Error::ParseError(concat!("Element ", $parent_name, " must not have more than one ", $name, " child.")));
        }
        $temp = Some(do_parse!($elem, $constructor));
    );
    ($temp:ident: Required = $constructor:ident => $elem:ident, $name:tt, $parent_name:tt) => (
        if $temp.is_some() {
            return Err(crate::error::Error::ParseError(concat!("Element ", $parent_name, " must not have more than one ", $name, " child.")));
        }
        $temp = Some(do_parse!($elem, $constructor));
    );
}

macro_rules! finish_parse_elem {
    ($temp:ident: Vec = $name:tt, $parent_name:tt) => (
        $temp
    );
    ($temp:ident: Option = $name:tt, $parent_name:tt) => (
        $temp
    );
    ($temp:ident: Required = $name:tt, $parent_name:tt) => (
        $temp.ok_or(crate::error::Error::ParseError(concat!("Missing child ", $name, " in ", $parent_name, " element.")))?
    );
}

macro_rules! generate_serialiser {
    ($parent:ident, $elem:ident, Required, String, ($name:tt, $ns:ident)) => (
        ::minidom::Element::builder($name)
            .ns(crate::ns::$ns)
            .append($parent.$elem)
            .build()
    );
    ($parent:ident, $elem:ident, Option, String, ($name:tt, $ns:ident)) => (
        $parent.$elem.map(|elem|
            ::minidom::Element::builder($name)
                .ns(crate::ns::$ns)
                .append(elem)
                .build())
    );
    ($parent:ident, $elem:ident, $_:ident, $constructor:ident, ($name:tt, $ns:ident)) => (
        $parent.$elem
    );
}

macro_rules! generate_element {
    ($(#[$meta:meta])* $elem:ident, $name:tt, $ns:ident, attributes: [$($(#[$attr_meta:meta])* $attr:ident: $attr_type:ty = $attr_name:tt => $attr_action:tt),+,]) => (
        generate_element!($(#[$meta])* $elem, $name, $ns, attributes: [$($(#[$attr_meta])* $attr: $attr_type = $attr_name => $attr_action),*], children: []);
    );
    ($(#[$meta:meta])* $elem:ident, $name:tt, $ns:ident, attributes: [$($(#[$attr_meta:meta])* $attr:ident: $attr_type:ty = $attr_name:tt => $attr_action:tt),+]) => (
        generate_element!($(#[$meta])* $elem, $name, $ns, attributes: [$($(#[$attr_meta])* $attr: $attr_type = $attr_name => $attr_action),*], children: []);
    );
    ($(#[$meta:meta])* $elem:ident, $name:tt, $ns:ident, children: [$($(#[$child_meta:meta])* $child_ident:ident: $coucou:tt<$child_type:ty> = ($child_name:tt, $child_ns:ident) => $child_constructor:ident),*]) => (
        generate_element!($(#[$meta])* $elem, $name, $ns, attributes: [], children: [$($(#[$child_meta])* $child_ident: $coucou<$child_type> = ($child_name, $child_ns) => $child_constructor),*]);
    );
    ($(#[$meta:meta])* $elem:ident, $name:tt, $ns:ident, attributes: [$($(#[$attr_meta:meta])* $attr:ident: $attr_type:ty = $attr_name:tt => $attr_action:tt),*,], children: [$($(#[$child_meta:meta])* $child_ident:ident: $coucou:tt<$child_type:ty> = ($child_name:tt, $child_ns:ident) => $child_constructor:ident),*]) => (
        generate_element!($(#[$meta])* $elem, $name, $ns, attributes: [$($(#[$attr_meta])* $attr: $attr_type = $attr_name => $attr_action),*], children: [$($(#[$child_meta])* $child_ident: $coucou<$child_type> = ($child_name, $child_ns) => $child_constructor),*]);
    );
    ($(#[$meta:meta])* $elem:ident, $name:tt, $ns:ident, text: ($(#[$text_meta:meta])* $text_ident:ident: $codec:ident < $text_type:ty >)) => (
        generate_element!($(#[$meta])* $elem, $name, $ns, attributes: [], children: [], text: ($(#[$text_meta])* $text_ident: $codec<$text_type>));
    );
    ($(#[$meta:meta])* $elem:ident, $name:tt, $ns:ident, attributes: [$($(#[$attr_meta:meta])* $attr:ident: $attr_type:ty = $attr_name:tt => $attr_action:tt),+], text: ($(#[$text_meta:meta])* $text_ident:ident: $codec:ident < $text_type:ty >)) => (
        generate_element!($(#[$meta])* $elem, $name, $ns, attributes: [$($(#[$attr_meta])* $attr: $attr_type = $attr_name => $attr_action),*], children: [], text: ($(#[$text_meta])* $text_ident: $codec<$text_type>));
    );
    ($(#[$meta:meta])* $elem:ident, $name:tt, $ns:ident, attributes: [$($(#[$attr_meta:meta])* $attr:ident: $attr_type:ty = $attr_name:tt => $attr_action:tt),*], children: [$($(#[$child_meta:meta])* $child_ident:ident: $coucou:tt<$child_type:ty> = ($child_name:tt, $child_ns:ident) => $child_constructor:ident),*] $(, text: ($(#[$text_meta:meta])* $text_ident:ident: $codec:ident < $text_type:ty >))*) => (
        $(#[$meta])*
        #[derive(Debug, Clone)]
        pub struct $elem {
            $(
            $(#[$attr_meta])*
            pub $attr: $attr_type,
            )*
            $(
            $(#[$child_meta])*
            pub $child_ident: start_decl!($coucou, $child_type),
            )*
            $(
            $(#[$text_meta])*
            pub $text_ident: $text_type,
            )*
        }

        impl ::try_from::TryFrom<::minidom::Element> for $elem {
            type Err = crate::error::Error;

            fn try_from(elem: ::minidom::Element) -> Result<$elem, crate::error::Error> {
                check_self!(elem, $name, $ns);
                check_no_unknown_attributes!(elem, $name, [$($attr_name),*]);
                $(
                start_parse_elem!($child_ident: $coucou);
                )*
                for _child in elem.children() {
                    $(
                    if _child.is($child_name, crate::ns::$child_ns) {
                        do_parse_elem!($child_ident: $coucou = $child_constructor => _child, $child_name, $name);
                        continue;
                    }
                    )*
                    return Err(crate::error::Error::ParseError(concat!("Unknown child in ", $name, " element.")));
                }
                Ok($elem {
                    $(
                    $attr: get_attr!(elem, $attr_name, $attr_action),
                    )*
                    $(
                    $child_ident: finish_parse_elem!($child_ident: $coucou = $child_name, $name),
                    )*
                    $(
                    $text_ident: $codec::decode(&elem.text())?,
                    )*
                })
            }
        }

        impl From<$elem> for ::minidom::Element {
            fn from(elem: $elem) -> ::minidom::Element {
                ::minidom::Element::builder($name)
                        .ns(crate::ns::$ns)
                        $(
                        .attr($attr_name, elem.$attr)
                        )*
                        $(
                        .append(generate_serialiser!(elem, $child_ident, $coucou, $child_constructor, ($child_name, $child_ns)))
                        )*
                        $(
                        .append($codec::encode(&elem.$text_ident))
                        )*
                        .build()
            }
        }
    );
}

macro_rules! assert_size (
    ($t:ty, $sz:expr) => (
        assert_eq!(::std::mem::size_of::<$t>(), $sz);
    );
);