macro: support tuple return types in functions

These are now *list* return types in perl.
However, currently there is no support for 'wantarray' or
lists of dynamic length.

Signed-off-by: Wolfgang Bumiller <w.bumiller@proxmox.com>
This commit is contained in:
Wolfgang Bumiller 2021-02-16 10:39:36 +01:00
parent 03644975f4
commit 705d6989ad
2 changed files with 290 additions and 78 deletions

View File

@ -43,6 +43,17 @@ impl ArgumentAttrs {
}
}
enum Return {
/// Return nothing. (This is different from returning an implicit undef!)
None(bool),
/// Return a single element.
Single(bool),
/// We support tuple return types. They act like "list" return types in perl.
Tuple(bool, usize),
}
pub fn handle_function(
attr: FunctionAttrs,
mut func: syn::ItemFn,
@ -57,10 +68,13 @@ pub fn handle_function(
}
let name = func.sig.ident.clone();
let xs_name = attr.xs_name.unwrap_or_else(|| match mangled_package_name {
None => Ident::new(&format!("xs_{}", name), name.span()),
Some(prefix) => Ident::new(&format!("xs_{}_{}", prefix, name), name.span()),
});
let xs_name = attr
.xs_name
.clone()
.unwrap_or_else(|| match mangled_package_name {
None => Ident::new(&format!("xs_{}", name), name.span()),
Some(prefix) => Ident::new(&format!("xs_{}_{}", prefix, name), name.span()),
});
let impl_xs_name = Ident::new(&format!("impl_xs_{}", name), name.span());
let mut extract_arguments = TokenStream::new();
@ -150,10 +164,11 @@ pub fn handle_function(
}
let has_return_value = match &func.sig.output {
syn::ReturnType::Default => false,
syn::ReturnType::Type(_arrow, ty) => match &**ty {
syn::Type::Tuple(tuple) => !tuple.elems.is_empty(),
_ => true,
syn::ReturnType::Default => Return::None(false),
syn::ReturnType::Type(_arrow, ty) => match get_result_type(&**ty) {
(syn::Type::Tuple(tuple), result) if tuple.elems.is_empty() => Return::None(result),
(syn::Type::Tuple(tuple), result) => Return::Tuple(result, tuple.elems.len()),
(_, result) => Return::Single(result),
},
};
@ -166,76 +181,18 @@ pub fn handle_function(
Span::call_site(),
);
let mut handle_return;
let return_type;
let wrapper_func;
if has_return_value {
return_type = quote! { *mut ::perlmod::ffi::SV };
handle_return = quote! {
let result = match #name(#passed_arguments) {
Ok(output) => output,
Err(err) => {
return Err(::perlmod::Value::new_string(&err.to_string())
.into_mortal()
.into_raw());
}
};
};
if attr.raw_return {
handle_return.extend(quote! {
Ok(result.into_mortal().into_raw())
});
} else {
handle_return.extend(quote! {
match ::perlmod::to_value(&result) {
Ok(value) => Ok(value.into_mortal().into_raw()),
Err(err) => Err(::perlmod::Value::new_string(&err.to_string())
.into_mortal()
.into_raw()),
}
});
};
wrapper_func = quote! {
#[no_mangle]
#[doc(hidden)]
pub extern "C" fn #xs_name(cv: &::perlmod::ffi::CV) {
unsafe {
match #impl_xs_name(cv) {
Ok(sv) => ::perlmod::ffi::stack_push_raw(sv),
Err(sv) => ::perlmod::ffi::croak(sv),
}
}
}
};
} else {
return_type = quote! { () };
if attr.raw_return {
bail!(&attr.raw_return => "raw_return attribute is illegal without a return value");
}
handle_return = quote! {
#name(#passed_arguments);
Ok(())
};
wrapper_func = quote! {
#[no_mangle]
#[doc(hidden)]
pub extern "C" fn #xs_name(cv: &::perlmod::ffi::CV) {
unsafe {
match #impl_xs_name(cv) {
Ok(()) => (),
Err(sv) => ::perlmod::ffi::croak(sv),
}
}
}
};
}
let ReturnHandling {
return_type,
handle_return,
wrapper_func,
} = handle_return_kind(
&attr,
has_return_value,
&name,
&xs_name,
&impl_xs_name,
passed_arguments,
)?;
let tokens = quote! {
#func
@ -277,3 +234,253 @@ pub fn handle_function(
tokens,
})
}
struct ReturnHandling {
return_type: TokenStream,
handle_return: TokenStream,
wrapper_func: TokenStream,
}
fn handle_return_kind(
attr: &FunctionAttrs,
ret: Return,
name: &Ident,
xs_name: &Ident,
impl_xs_name: &Ident,
passed_arguments: TokenStream,
) -> Result<ReturnHandling, Error> {
let return_type;
let mut handle_return;
let wrapper_func;
match ret {
Return::None(result) => {
return_type = quote! { () };
if attr.raw_return {
bail!(&attr.raw_return => "raw_return attribute is illegal without a return value");
}
if result {
handle_return = quote! {
match #name(#passed_arguments) {
Ok(()) => (),
Err(err) => {
return Err(::perlmod::Value::new_string(&err.to_string())
.into_mortal()
.into_raw());
}
}
Ok(())
};
} else {
handle_return = quote! {
#name(#passed_arguments);
Ok(())
};
}
wrapper_func = quote! {
#[no_mangle]
#[doc(hidden)]
pub extern "C" fn #xs_name(cv: &::perlmod::ffi::CV) {
unsafe {
match #impl_xs_name(cv) {
Ok(()) => (),
Err(sv) => ::perlmod::ffi::croak(sv),
}
}
}
};
}
Return::Single(result) => {
return_type = quote! { *mut ::perlmod::ffi::SV };
if result {
handle_return = quote! {
let result = match #name(#passed_arguments) {
Ok(output) => output,
Err(err) => {
return Err(::perlmod::Value::new_string(&err.to_string())
.into_mortal()
.into_raw());
}
};
};
} else {
handle_return = quote! {
let result = #name(#passed_arguments);
};
}
if attr.raw_return {
handle_return.extend(quote! {
Ok(result.into_mortal().into_raw())
});
} else {
handle_return.extend(quote! {
match ::perlmod::to_value(&result) {
Ok(value) => Ok(value.into_mortal().into_raw()),
Err(err) => Err(::perlmod::Value::new_string(&err.to_string())
.into_mortal()
.into_raw()),
}
});
};
wrapper_func = quote! {
#[no_mangle]
#[doc(hidden)]
pub extern "C" fn #xs_name(cv: &::perlmod::ffi::CV) {
unsafe {
match #impl_xs_name(cv) {
Ok(sv) => ::perlmod::ffi::stack_push_raw(sv),
Err(sv) => ::perlmod::ffi::croak(sv),
}
}
}
};
}
Return::Tuple(result, count) => {
return_type = {
let mut rt = TokenStream::new();
for _ in 0..count {
rt.extend(quote! { *mut ::perlmod::ffi::SV, });
}
quote! { (#rt) }
};
if result {
handle_return = quote! {
let result = match #name(#passed_arguments) {
Ok(output) => output,
Err(err) => {
return Err(::perlmod::Value::new_string(&err.to_string())
.into_mortal()
.into_raw());
}
};
};
} else {
handle_return = quote! {
let result = match #name(#passed_arguments);
};
}
if attr.raw_return {
let mut rt = TokenStream::new();
for i in 0..count {
let i = simple_usize(i, Span::call_site());
rt.extend(quote! { (result.#i).into_mortal().into_raw(), });
}
handle_return.extend(quote! {
Ok((#rt))
});
} else {
let mut rt = TokenStream::new();
for i in 0..count {
let i = simple_usize(i, Span::call_site());
rt.extend(quote! {
match ::perlmod::to_value(&result.#i) {
Ok(value) => value.into_mortal().into_raw(),
Err(err) => return Err(::perlmod::Value::new_string(&err.to_string())
.into_mortal()
.into_raw()),
},
});
}
handle_return.extend(quote! {
Ok((#rt))
});
}
let icount = simple_usize(count, Span::call_site());
let sp_offset = simple_usize(count - 1, Span::call_site());
let mut push = quote! {
::perlmod::ffi::RSPL_stack_resize_by(#icount);
let mut sp = ::perlmod::ffi::RSPL_stack_sp().sub(#sp_offset);
*sp = sv.0;
};
for i in 1..count {
let i = simple_usize(i, Span::call_site());
push.extend(quote! {
sp = sp.add(1);
*sp = sv.#i;
});
}
//let mut push = TokenStream::new();
//for i in 0..count {
// let i = simple_usize(i, Span::call_site());
// push.extend(quote! {
// ::perlmod::ffi::stack_push_raw(sv.#i);
// });
//}
wrapper_func = quote! {
#[no_mangle]
#[doc(hidden)]
pub extern "C" fn #xs_name(cv: &::perlmod::ffi::CV) {
unsafe {
match #impl_xs_name(cv) {
Ok(sv) => { #push },
Err(sv) => ::perlmod::ffi::croak(sv),
}
}
}
};
}
}
Ok(ReturnHandling {
return_type,
handle_return,
wrapper_func,
})
}
/// Note that we cannot handle renamed imports at all here...
pub fn is_result_type(ty: &syn::Type) -> Option<&syn::Type> {
if let syn::Type::Path(p) = ty {
if p.qself.is_some() {
return None;
}
let segs = &p.path.segments;
let is_result = match segs.len() {
1 => segs.last().unwrap().ident == "Result",
2 => segs.first().unwrap().ident == "std" && segs.last().unwrap().ident == "Result",
_ => false,
};
if !is_result {
return None;
}
if let syn::PathArguments::AngleBracketed(generic) = &segs.last().unwrap().arguments {
// We allow aliased Result types with an implicit Error:
if generic.args.len() != 1 && generic.args.len() != 2 {
return None;
}
if let syn::GenericArgument::Type(ty) = generic.args.first().unwrap() {
return Some(ty);
}
}
}
None
}
/// If the type is a Result type, return the contained Ok type, otherwise return the type itself.
/// Also return whether or not it actually was a Result.
pub fn get_result_type(ty: &syn::Type) -> (&syn::Type, bool) {
match is_result_type(ty) {
Some(ty) => (ty, true),
None => (ty, false),
}
}
/// Get a non-suffixed integer from an usize.
fn simple_usize(i: usize, span: Span) -> syn::LitInt {
syn::LitInt::new(&format!("{}", i), span)
}

View File

@ -45,6 +45,11 @@ mod export {
perlmod::destructor!(this, Bless: CLASSNAME);
}
#[export]
fn multi_return(#[raw] _this: Value) -> Result<(u32, u32), std::convert::Infallible> {
Ok((17, 32))
}
impl<'a> TryFrom<&'a Value> for &'a Bless {
type Error = Error;