xso-proc: completely overengineer everything for no good reason!
Well, not really, of course. All of this will make sense once we start adding support for fields and non-struct types. Refactoring the code now before we start to add actual member field parsing is much easier. How do I know that this will work out? Well, my crystal ball knows it. Don't believe me? Okay, ChatGPT told me ... Alright alright, I went through the entire process of implementing this feature *twice* at this point and have a pretty good idea of where to draw the abstraction lines so that everything falls neatly into place. You'll have to trust me on this one. (Or, you know, check out old branches in my xmpp-rs repo. That might work, too. `feature/derive-macro-streaming-full` might be a name to look for if you dare.)
This commit is contained in:
Jonas Schäfer
parent
bf7816d321
commit
183bef5cf6
10 changed files with 930 additions and 135 deletions
|
|
@ -10,6 +10,7 @@ use proc_macro2::TokenStream;
|
|||
use quote::quote;
|
||||
use syn::*;
|
||||
|
||||
use crate::compound::Compound;
|
||||
use crate::meta::{NameRef, NamespaceRef, XmlCompoundMeta};
|
||||
|
||||
/// Parts necessary to construct a `::xso::FromXml` implementation.
|
||||
|
|
@ -44,6 +45,9 @@ pub(crate) struct StructDef {
|
|||
/// The XML name of the element to map the struct to.
|
||||
name: NameRef,
|
||||
|
||||
/// The field(s) of this struct.
|
||||
inner: Compound,
|
||||
|
||||
/// Name of the target type.
|
||||
target_ty_ident: Ident,
|
||||
|
||||
|
|
@ -65,19 +69,10 @@ impl StructDef {
|
|||
return Err(Error::new(meta.span, "`name` is required on structs"));
|
||||
};
|
||||
|
||||
match fields {
|
||||
Fields::Unit => (),
|
||||
other => {
|
||||
return Err(Error::new_spanned(
|
||||
other,
|
||||
"cannot derive on non-unit struct (yet!)",
|
||||
))
|
||||
}
|
||||
}
|
||||
|
||||
Ok(Self {
|
||||
namespace,
|
||||
name,
|
||||
inner: Compound::from_fields(fields)?,
|
||||
target_ty_ident: ident.clone(),
|
||||
builder_ty_ident: quote::format_ident!("{}FromXmlBuilder", ident),
|
||||
event_iter_ty_ident: quote::format_ident!("{}IntoXmlIterator", ident),
|
||||
|
|
@ -95,68 +90,43 @@ impl StructDef {
|
|||
|
||||
let target_ty_ident = &self.target_ty_ident;
|
||||
let builder_ty_ident = &self.builder_ty_ident;
|
||||
let state_ty_name = quote::format_ident!("{}State", builder_ty_ident);
|
||||
let state_ty_ident = quote::format_ident!("{}State", builder_ty_ident);
|
||||
|
||||
let unknown_attr_err = format!(
|
||||
"Unknown attribute in {} element.",
|
||||
xml_name.repr_to_string()
|
||||
);
|
||||
let unknown_child_err = format!("Unknown child in {} element.", xml_name.repr_to_string());
|
||||
|
||||
let docstr = format!("Build a [`{}`] from XML events", target_ty_ident);
|
||||
|
||||
Ok(FromXmlParts {
|
||||
defs: quote! {
|
||||
enum #state_ty_name {
|
||||
Default,
|
||||
}
|
||||
|
||||
#[doc = #docstr]
|
||||
#vis struct #builder_ty_ident(::core::option::Option<#state_ty_name>);
|
||||
|
||||
impl ::xso::FromEventsBuilder for #builder_ty_ident {
|
||||
type Output = #target_ty_ident;
|
||||
|
||||
fn feed(
|
||||
&mut self,
|
||||
ev: ::xso::exports::rxml::Event
|
||||
) -> ::core::result::Result<::core::option::Option<Self::Output>, ::xso::error::Error> {
|
||||
match self.0 {
|
||||
::core::option::Option::None => panic!("feed() called after it returned a non-None value"),
|
||||
::core::option::Option::Some(#state_ty_name::Default) => match ev {
|
||||
::xso::exports::rxml::Event::StartElement(..) => {
|
||||
::core::result::Result::Err(::xso::error::Error::Other(#unknown_child_err))
|
||||
}
|
||||
::xso::exports::rxml::Event::EndElement(..) => {
|
||||
self.0 = ::core::option::Option::None;
|
||||
::core::result::Result::Ok(::core::option::Option::Some(#target_ty_ident))
|
||||
}
|
||||
::xso::exports::rxml::Event::Text(..) => {
|
||||
::core::result::Result::Err(::xso::error::Error::Other("Unexpected text content".into()))
|
||||
}
|
||||
// we ignore these: a correct parser only generates
|
||||
// them at document start, and there we want to indeed
|
||||
// not worry about them being in front of the first
|
||||
// element.
|
||||
::xso::exports::rxml::Event::XmlDeclaration(_, ::xso::exports::rxml::XmlVersion::V1_0) => ::core::result::Result::Ok(::core::option::Option::None)
|
||||
}
|
||||
}
|
||||
let defs = self
|
||||
.inner
|
||||
.make_from_events_statemachine(
|
||||
&state_ty_ident,
|
||||
&target_ty_ident.clone().into(),
|
||||
"Struct",
|
||||
)?
|
||||
.with_augmented_init(|init| {
|
||||
quote! {
|
||||
if name.0 != #xml_namespace || name.1 != #xml_name {
|
||||
::core::result::Result::Err(::xso::error::FromEventsError::Mismatch {
|
||||
name,
|
||||
attrs,
|
||||
})
|
||||
} else {
|
||||
#init
|
||||
}
|
||||
}
|
||||
},
|
||||
})
|
||||
.compile()
|
||||
.render(
|
||||
vis,
|
||||
&builder_ty_ident,
|
||||
&state_ty_ident,
|
||||
&TypePath {
|
||||
qself: None,
|
||||
path: target_ty_ident.clone().into(),
|
||||
}
|
||||
.into(),
|
||||
)?;
|
||||
|
||||
Ok(FromXmlParts {
|
||||
defs,
|
||||
from_events_body: quote! {
|
||||
if #name_ident.0 != #xml_namespace || #name_ident.1 != #xml_name {
|
||||
return ::core::result::Result::Err(::xso::error::FromEventsError::Mismatch {
|
||||
name: #name_ident,
|
||||
attrs: #attrs_ident,
|
||||
});
|
||||
}
|
||||
if attrs.len() > 0 {
|
||||
return ::core::result::Result::Err(::xso::error::Error::Other(
|
||||
#unknown_attr_err,
|
||||
).into());
|
||||
}
|
||||
::core::result::Result::Ok(#builder_ty_ident(::core::option::Option::Some(#state_ty_name::Default)))
|
||||
#builder_ty_ident::new(#name_ident, #attrs_ident)
|
||||
},
|
||||
builder_ty_ident: builder_ty_ident.clone(),
|
||||
})
|
||||
|
|
@ -168,49 +138,36 @@ impl StructDef {
|
|||
|
||||
let target_ty_ident = &self.target_ty_ident;
|
||||
let event_iter_ty_ident = &self.event_iter_ty_ident;
|
||||
let state_ty_name = quote::format_ident!("{}State", event_iter_ty_ident);
|
||||
let state_ty_ident = quote::format_ident!("{}State", event_iter_ty_ident);
|
||||
|
||||
let docstr = format!("Decompose a [`{}`] into XML events", target_ty_ident);
|
||||
let defs = self
|
||||
.inner
|
||||
.make_into_event_iter_statemachine(&target_ty_ident.clone().into(), "Struct")?
|
||||
.with_augmented_init(|init| {
|
||||
quote! {
|
||||
let name = (
|
||||
::xso::exports::rxml::Namespace::from(#xml_namespace),
|
||||
#xml_name.into(),
|
||||
);
|
||||
#init
|
||||
}
|
||||
})
|
||||
.compile()
|
||||
.render(
|
||||
vis,
|
||||
&TypePath {
|
||||
qself: None,
|
||||
path: target_ty_ident.clone().into(),
|
||||
}
|
||||
.into(),
|
||||
&state_ty_ident,
|
||||
&event_iter_ty_ident,
|
||||
)?;
|
||||
|
||||
Ok(IntoXmlParts {
|
||||
defs: quote! {
|
||||
enum #state_ty_name {
|
||||
Header,
|
||||
Footer,
|
||||
}
|
||||
|
||||
#[doc = #docstr]
|
||||
#vis struct #event_iter_ty_ident(::core::option::Option<#state_ty_name>);
|
||||
|
||||
impl ::std::iter::Iterator for #event_iter_ty_ident {
|
||||
type Item = ::core::result::Result<::xso::exports::rxml::Event, ::xso::error::Error>;
|
||||
|
||||
fn next(&mut self) -> ::core::option::Option<Self::Item> {
|
||||
match self.0 {
|
||||
::core::option::Option::Some(#state_ty_name::Header) => {
|
||||
self.0 = ::core::option::Option::Some(#state_ty_name::Footer);
|
||||
::core::option::Option::Some(::core::result::Result::Ok(::xso::exports::rxml::Event::StartElement(
|
||||
::xso::exports::rxml::parser::EventMetrics::zero(),
|
||||
(
|
||||
::xso::exports::rxml::Namespace::from_str(#xml_namespace),
|
||||
#xml_name.to_owned(),
|
||||
),
|
||||
::xso::exports::rxml::AttrMap::new(),
|
||||
)))
|
||||
}
|
||||
::core::option::Option::Some(#state_ty_name::Footer) => {
|
||||
self.0 = ::core::option::Option::None;
|
||||
::core::option::Option::Some(::core::result::Result::Ok(::xso::exports::rxml::Event::EndElement(
|
||||
::xso::exports::rxml::parser::EventMetrics::zero(),
|
||||
)))
|
||||
}
|
||||
::core::option::Option::None => ::core::option::Option::None,
|
||||
}
|
||||
}
|
||||
}
|
||||
},
|
||||
defs,
|
||||
into_event_iter_body: quote! {
|
||||
::core::result::Result::Ok(#event_iter_ty_ident(::core::option::Option::Some(#state_ty_name::Header)))
|
||||
#event_iter_ty_ident::new(self)
|
||||
},
|
||||
event_iter_ty_ident: event_iter_ty_ident.clone(),
|
||||
})
|
||||
|
|
|
|||
Loading…
Reference in a new issue