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xso: implement catch-all for unknown elements

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This commit is contained in:
Jonas Schäfer 2024-08-05 08:20:25 +02:00
commit 0361b5905b
10 changed files with 412 additions and 48 deletions
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8
xso-proc/src/field/child.rs
View file

@ -23,7 +23,7 @@ use crate::types::{
option_as_xml_ty, option_ty, ref_ty, ty_from_ident,
};
use super::{Field, FieldBuilderPart, FieldIteratorPart, FieldTempInit};
use super::{Field, FieldBuilderPart, FieldIteratorPart, FieldTempInit, NestedMatcher};
/// The field maps to a child
pub(super) struct ChildField {
@ -101,7 +101,7 @@ impl Field for ChildField {
init: quote! { ::core::option::Option::None },
ty: option_ty(ty.clone()),
},
matcher: quote! {
matcher: NestedMatcher::Selective(quote! {
match #matcher {
::core::result::Result::Ok(v) => if #field_access.is_some() {
::core::result::Result::Err(::xso::error::FromEventsError::Invalid(::xso::error::Error::Other(#duplicate_msg)))
@ -110,7 +110,7 @@ impl Field for ChildField {
},
::core::result::Result::Err(e) => ::core::result::Result::Err(e),
}
},
}),
builder,
collect: quote! {
#field_access = ::core::option::Option::Some(#fetch);
@ -132,7 +132,7 @@ impl Field for ChildField {
init: quote! { #ty_default() },
ty: ty.clone(),
},
matcher,
matcher: NestedMatcher::Selective(matcher),
builder,
collect: quote! {
#ty_extend(&mut #field_access, [#fetch]);

110
xso-proc/src/field/element.rs Normal file
View file

@ -0,0 +1,110 @@
// Copyright (c) 2024 Jonas Schäfer <jonas@zombofant.net>
//
// 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/.
//! This module concerns the processing of untyped `minidom::Element`
//! children.
//!
//! In particular, it provides the `#[xml(element)]` implementation.
use proc_macro2::{Span, TokenStream};
use quote::quote;
use syn::*;
use crate::error_message::ParentRef;
use crate::scope::{AsItemsScope, FromEventsScope};
use crate::types::{
default_fn, element_ty, from_xml_builder_ty, into_iterator_into_iter_fn, into_iterator_iter_ty,
item_iter_ty, option_ty, ref_ty,
};
use super::{Field, FieldBuilderPart, FieldIteratorPart, FieldTempInit, NestedMatcher};
pub(super) struct ElementField;
impl Field for ElementField {
fn make_builder_part(
&self,
scope: &FromEventsScope,
_container_name: &ParentRef,
member: &Member,
ty: &Type,
) -> Result<FieldBuilderPart> {
let FromEventsScope {
ref substate_result,
..
} = scope;
let field_access = scope.access_field(member);
let element_ty = element_ty(Span::call_site());
let default_fn = default_fn(ty.clone());
let builder = from_xml_builder_ty(element_ty.clone());
Ok(FieldBuilderPart::Nested {
extra_defs: TokenStream::default(),
value: FieldTempInit {
init: quote! { #default_fn() },
ty: ty.clone(),
},
matcher: NestedMatcher::Fallback(quote! {
#builder::new(name, attrs)
}),
builder,
collect: quote! {
<#ty as ::core::iter::Extend::<#element_ty>>::extend(&mut #field_access, [#substate_result]);
},
finalize: quote! {
#field_access
},
})
}
fn make_iterator_part(
&self,
scope: &AsItemsScope,
_container_name: &ParentRef,
bound_name: &Ident,
_member: &Member,
ty: &Type,
) -> Result<FieldIteratorPart> {
let AsItemsScope { ref lifetime, .. } = scope;
let element_ty = element_ty(Span::call_site());
let iter_ty = item_iter_ty(element_ty.clone(), lifetime.clone());
let element_iter = into_iterator_iter_ty(ref_ty(ty.clone(), lifetime.clone()));
let into_iter = into_iterator_into_iter_fn(ref_ty(ty.clone(), lifetime.clone()));
let state_ty = Type::Tuple(TypeTuple {
paren_token: token::Paren::default(),
elems: [element_iter, option_ty(iter_ty)].into_iter().collect(),
});
Ok(FieldIteratorPart::Content {
extra_defs: TokenStream::default(),
value: FieldTempInit {
init: quote! {
(#into_iter(#bound_name), ::core::option::Option::None)
},
ty: state_ty,
},
generator: quote! {
loop {
if let ::core::option::Option::Some(current) = #bound_name.1.as_mut() {
if let ::core::option::Option::Some(item) = current.next() {
break ::core::option::Option::Some(item).transpose();
}
}
if let ::core::option::Option::Some(item) = #bound_name.0.next() {
#bound_name.1 = ::core::option::Option::Some(
<#element_ty as ::xso::AsXml>::as_xml_iter(item)?
);
} else {
break ::core::result::Result::Ok(::core::option::Option::None)
}
}
},
})
}
}

75
xso-proc/src/field/mod.rs
View file

@ -18,10 +18,14 @@ use crate::scope::{AsItemsScope, FromEventsScope};
mod attribute;
mod child;
#[cfg(feature = "minidom")]
mod element;
mod text;
use self::attribute::AttributeField;
use self::child::{ChildField, ExtractDef};
#[cfg(feature = "minidom")]
use self::element::ElementField;
use self::text::TextField;
/// Code slices necessary for declaring and initializing a temporary variable
@ -34,6 +38,33 @@ pub(crate) struct FieldTempInit {
pub(crate) init: TokenStream,
}
/// Configure how a nested field builder selects child elements.
pub(crate) enum NestedMatcher {
/// Matches a specific child element fallabily.
Selective(
/// Expression which evaluates to `Result<T, FromEventsError>`,
/// consuming `name: rxml::QName` and `attrs: rxml::AttrMap`.
///
/// `T` must be the type specified in the
/// [`FieldBuilderPart::Nested::builder`] field.
TokenStream,
),
#[cfg_attr(not(feature = "minidom"), allow(dead_code))]
/// Matches any child element not matched by another matcher.
///
/// Only a single field may use this variant, otherwise an error is
/// raised during execution of the proc macro.
Fallback(
/// Expression which evaluates to `T` (or `return`s an error),
/// consuming `name: rxml::QName` and `attrs: rxml::AttrMap`.
///
/// `T` must be the type specified in the
/// [`FieldBuilderPart::Nested::builder`] field.
TokenStream,
),
}
/// Describe how a struct or enum variant's member is parsed from XML data.
///
/// This struct is returned from [`FieldDef::make_builder_part`] and
@ -73,12 +104,9 @@ pub(crate) enum FieldBuilderPart {
/// parsing.
value: FieldTempInit,
/// Expression which evaluates to `Result<T, FromEventsError>`,
/// consuming `name: rxml::QName` and `attrs: rxml::AttrMap`.
///
/// `T` must be the type specified in the
/// [`Self::Nested::builder`] field.
matcher: TokenStream,
/// Configure child matching behaviour for this field. See
/// [`NestedMatcher`] for options.
matcher: NestedMatcher,
/// Type implementing `xso::FromEventsBuilder` which parses the child
/// element.
@ -343,6 +371,31 @@ fn new_field(
}),
}))
}
#[cfg(feature = "minidom")]
XmlFieldMeta::Element { span, amount } => {
match amount {
Some(AmountConstraint::Any(_)) => (),
Some(AmountConstraint::FixedSingle(span)) => {
return Err(Error::new(
span,
"only `n = ..` is supported for #[xml(element)]` currently",
))
}
None => return Err(Error::new(span, "`n` must be set to `..` currently")),
}
Ok(Box::new(ElementField))
}
#[cfg(not(feature = "minidom"))]
XmlFieldMeta::Element { span, amount } => {
let _ = amount;
Err(Error::new(
span,
"#[xml(element)] requires xso to be built with the \"minidom\" feature.",
))
}
}
}
@ -351,6 +404,9 @@ fn new_field(
/// See [`Compound`][`crate::compound::Compound`] for more information on
/// compounds in general.
pub(crate) struct FieldDef {
/// A span which refers to the field's definition.
span: Span,
/// The member identifying the field.
member: Member,
@ -388,6 +444,7 @@ impl FieldDef {
let ty = field.ty.clone();
Ok(Self {
span: field_span,
inner: new_field(meta, ident, &ty, container_namespace)?,
member,
ty,
@ -406,6 +463,7 @@ impl FieldDef {
) -> Result<Self> {
let span = meta.span();
Ok(Self {
span,
member: Member::Unnamed(Index { index, span }),
ty: ty.clone(),
inner: new_field(meta, None, ty, container_namespace)?,
@ -454,4 +512,9 @@ impl FieldDef {
pub(crate) fn is_text_field(&self) -> bool {
self.inner.captures_text()
}
/// Return a span which points at the field's definition.'
pub(crate) fn span(&self) -> Span {
self.span
}
}