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chore: refactored macro more

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This commit is contained in:
əlemi 2024-09-21 20:46:48 +02:00
parent f136071c10
commit e855659e1a
Signed by: alemi
GPG key ID: A4895B84D311642C
5 changed files with 103 additions and 304 deletions
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224
macro/macro.rs
View file

@ -1,224 +0,0 @@
#[proc_macro_attribute]
pub fn jni(
attrs: proc_macro::TokenStream,
input: proc_macro::TokenStream,
) -> proc_macro::TokenStream {
generate_jni_wrapper(
syn::parse_macro_input!(attrs),
syn::parse_macro_input!(input),
)
.unwrap()
.into()
}
use proc_macro2::{Span, TokenStream, TokenTree};
use quote::TokenStreamExt;
use syn::{FnArg, Item, ReturnType, Type};
fn generate_jni_wrapper(attrs: TokenStream, input: TokenStream) -> Result<TokenStream, syn::Error> {
let mut out = TokenStream::new();
let Item::Fn(fn_item) = syn::parse2(input.clone())? else {
return Err(syn::Error::new(Span::call_site(), "#[jni] is only supported on functions"));
};
let mut what_next = WhatNext::Nothing;
let mut package = None;
let mut clazz = None;
let mut exception = None;
let mut return_pointer = false;
for attr in attrs {
match what_next {
WhatNext::Nothing => {
if let TokenTree::Ident(ref i) = attr {
match i.to_string().as_ref() {
"package" => what_next = WhatNext::Package,
"class" => what_next = WhatNext::Class,
"exception" => what_next = WhatNext::Exception,
"ptr" => return_pointer = true,
_ => return Err(syn::Error::new(Span::call_site(), "unexpected attribute on macro: {attr}")),
}
}
},
WhatNext::Class => {
if let TokenTree::Literal(i) = attr {
let raw = i.to_string().replace('"', "");
clazz = Some(syn::Ident::new(&raw, Span::call_site()));
what_next = WhatNext::Nothing;
}
},
WhatNext::Package => {
if let TokenTree::Literal(i) = attr {
let raw = i.to_string().replace('"', "").replace(".", "_");
package = Some(syn::Ident::new(&raw, Span::call_site()));
what_next = WhatNext::Nothing;
}
},
WhatNext::Exception => {
if let TokenTree::Literal(i) = attr {
let raw = i.to_string().replace('"', "").replace(".", "_");
exception = Some(raw);
what_next = WhatNext::Nothing;
}
}
}
}
let Some(package) = package else { return Err(syn::Error::new(Span::call_site(), "missing attribute 'package'")) };
let Some(clazz) = clazz else { return Err(syn::Error::new(Span::call_site(), "missing attribute 'class'")) };
let (could_error, ret_type) = match fn_item.sig.output {
syn::ReturnType::Default => (false, fn_item.sig.output),
syn::ReturnType::Type(_tok, ty) => match *ty {
syn::Type::Path(ref path) => {
let Some(last) = path.path.segments.last() else {
return Err(syn::Error::new(Span::call_site(), "empty Result type is not valid"));
};
// TODO this is terrible, macro returns a function and we call it?? there must be a
// better way!!!
let mut out = (
false,
ReturnType::Type(syn::Token![->](Span::call_site()), Box::new(Type::Path(path.clone())))
);
if last.ident == "Result" {
match &last.arguments {
syn::PathArguments::None => return Err(syn::Error::new(Span::call_site(), "Result without generics is not valid")),
syn::PathArguments::Parenthesized(_) => return Err(syn::Error::new(Span::call_site(), "Parenthesized Result is not valid")),
syn::PathArguments::AngleBracketed(ref generics) => for generic in generics.args.iter() {
match generic {
syn::GenericArgument::Lifetime(_) => continue,
syn::GenericArgument::Type(ty) => {
out = (true, ReturnType::Type(syn::Token![->](Span::call_site()), Box::new(ty.clone())));
break;
},
_ => return Err(syn::Error::new(Span::call_site(), "unexpected type in Result")),
}
}
}
}
out
},
_ => return Err(syn::Error::new(Span::call_site(), "unsupported return type")),
},
};
let mut incoming = TokenStream::new();
let mut forwarding = TokenStream::new();
for arg in fn_item.sig.inputs {
let FnArg::Typed(ty) = arg else {
return Err(syn::Error::new(Span::call_site(), "#[jni] macro doesn't work on methods"));
};
incoming.append_all(quote::quote!( #ty , ));
let pat = unpack_pat(*ty.pat)?;
forwarding.append_all(pat);
}
let name = fn_item.sig.ident.to_string();
let name_jni = name.replace("_", "_1");
let fn_name_inner = syn::Ident::new(&name, Span::call_site());
let fn_name = syn::Ident::new(&format!("Java_{package}_{clazz}_{name_jni}"), Span::call_site());
let Some(env_ident) = forwarding.clone().into_iter().next() else {
return Err(syn::Error::new(Span::call_site(), "missing JNIEnv argument"));
};
let return_expr = if return_pointer {
quote::quote!( std::ptr::null_mut() )
} else {
quote::quote!( 0 )
};
let wrapped = if could_error {
if let Some(exception) = exception {
// V----------------------------------V
quote::quote! {
#[no_mangle]
#[allow(unused_mut)]
pub extern "system" fn #fn_name<'local>(#incoming) #ret_type {
use jni_toolbox::JniToolboxError;
match #fn_name_inner(#forwarding) {
Ok(ret) => ret,
Err(e) => match #env_ident.throw_new(#exception, format!("{e:?}")) {
Ok(_) => return #return_expr,
Err(e) => panic!("error throwing java exception: {e}"),
}
}
}
}
// ^----------------------------------^
} else {
// V----------------------------------V
quote::quote! {
#[no_mangle]
#[allow(unused_mut)]
pub extern "system" fn #fn_name<'local>(#incoming) #ret_type {
use jni_toolbox::JniToolboxError;
// NOTE: this is SAFE! the cloned env reference lives less than the actual one, we just lack a
// way to get it back from the called function and thus resort to unsafe cloning
let mut env_copy = unsafe { #env_ident.unsafe_clone() };
match #fn_name_inner(#forwarding) {
Err(e) => match env_copy.find_class(e.jclass()) {
Err(e) => panic!("error throwing Java exception -- failed resolving error class: {e}"),
Ok(class) => match env_copy.new_string(format!("{e:?}")) {
Err(e) => panic!("error throwing Java exception -- failed creating error string: {e}"),
Ok(msg) => match env_copy.new_object(class, "(Ljava/lang/String;)V", &[jni::objects::JValueGen::Object(&msg)]) {
Err(e) => panic!("error throwing Java exception -- failed creating object: {e}"),
Ok(obj) => match env_copy.throw(jni::objects::JThrowable::from(obj)) {
Err(e) => panic!("error throwing Java exception -- failed throwing: {e}"),
Ok(_) => return #return_expr,
},
},
},
}
Ok(ret) => ret,
}
}
}
// ^----------------------------------^
}
} else {
// V----------------------------------V
quote::quote! {
#[no_mangle]
#[allow(unused_mut)]
pub extern "system" fn #fn_name<'local>(#incoming) #ret_type {
#fn_name_inner(#forwarding)
}
}
// ^----------------------------------^
};
out.append_all(input);
out.append_all(wrapped);
Ok(out)
}
enum WhatNext {
Nothing,
Package,
Class,
Exception,
}
fn unpack_pat(pat: syn::Pat) -> Result<TokenStream, syn::Error> {
match pat {
syn::Pat::Ident(i) => {
let ident = i.ident;
Ok(quote::quote!( #ident ,))
},
syn::Pat::Reference(r) => {
unpack_pat(*r.pat)
},
_ => Err(syn::Error::new(Span::call_site(), "unsupported argument type")),
}
}

30
macro/src/args.rs Normal file
View file

@ -0,0 +1,30 @@
use proc_macro2::{Span, TokenStream};
use quote::TokenStreamExt;
fn unpack_pat(pat: syn::Pat) -> Result<TokenStream, syn::Error> {
match pat {
syn::Pat::Ident(i) => {
let ident = i.ident;
Ok(quote::quote!( #ident ,))
},
syn::Pat::Reference(r) => {
unpack_pat(*r.pat)
},
_ => Err(syn::Error::new(Span::call_site(), "unsupported argument type")),
}
}
pub(crate) fn parse_args(fn_item: syn::ItemFn) -> Result<(TokenStream, TokenStream), syn::Error> {
let mut incoming = TokenStream::new();
let mut forwarding = TokenStream::new();
for arg in fn_item.sig.inputs {
let syn::FnArg::Typed(ty) = arg else {
return Err(syn::Error::new(Span::call_site(), "#[jni] macro doesn't work on methods"));
};
incoming.append_all(quote::quote!( #ty , ));
let pat = unpack_pat(*ty.pat)?;
forwarding.append_all(pat);
}
Ok((incoming, forwarding))
}

2
macro/src/lib.rs
View file

@ -1,5 +1,7 @@
mod attrs;
mod wrapper;
mod args;
mod ret;
/// wrap this function in in a JNI exported fn

48
macro/src/ret.rs Normal file
View file

@ -0,0 +1,48 @@
use proc_macro2::{Span, TokenStream};
use quote::ToTokens;
use syn::{ReturnType, Type};
#[derive(Clone)]
pub(crate) struct ReturnOptions {
pub(crate) ty: Option<Box<Type>>,
pub(crate) result: bool,
}
impl ReturnOptions {
pub(crate) fn parse_signature(ret: ReturnType) -> Result<Self, syn::Error> {
match ret {
syn::ReturnType::Default => Ok(Self { ty: None, result: false }),
syn::ReturnType::Type(_tok, ty) => match *ty {
syn::Type::Path(ref path) => {
let Some(last) = path.path.segments.last() else {
return Err(syn::Error::new(Span::call_site(), "empty Result type is not valid"));
};
if last.ident == "Result" {
match &last.arguments {
syn::PathArguments::None => return Err(syn::Error::new(Span::call_site(), "Result without generics is not valid")),
syn::PathArguments::Parenthesized(_) => return Err(syn::Error::new(Span::call_site(), "Parenthesized Result is not valid")),
syn::PathArguments::AngleBracketed(ref generics) => for generic in generics.args.iter() {
match generic {
syn::GenericArgument::Lifetime(_) => continue,
syn::GenericArgument::Type(ty) => return Ok(Self { ty: Some(Box::new(ty.clone())), result: true }),
_ => return Err(syn::Error::new(Span::call_site(), "unexpected type in Result")),
}
}
}
}
Ok(Self { ty: Some(Box::new(Type::Path(path.clone()))), result: false })
},
_ => Err(syn::Error::new(Span::call_site(), "unsupported return type")),
},
}
}
pub(crate) fn tokens(self) -> TokenStream {
match self.ty {
Some(t) => ReturnType::Type(syn::Token![->](Span::call_site()), t).to_token_stream(),
None => ReturnType::Default.to_token_stream(),
}
}
}

103
macro/src/wrapper.rs
View file

@ -1,8 +1,8 @@
use proc_macro2::{Span, TokenStream};
use quote::TokenStreamExt;
use syn::{FnArg, Item, ReturnType, Type};
use syn::Item;
use crate::attrs::AttrsOptions;
use crate::{args::parse_args, attrs::AttrsOptions, ret::ReturnOptions};
pub(crate) fn generate_jni_wrapper(attrs: TokenStream, input: TokenStream) -> Result<TokenStream, syn::Error> {
let mut out = TokenStream::new();
@ -12,65 +12,23 @@ pub(crate) fn generate_jni_wrapper(attrs: TokenStream, input: TokenStream) -> Re
};
let attrs = AttrsOptions::parse_attr(attrs)?;
let (could_error, ret_type) = match fn_item.sig.output {
syn::ReturnType::Default => (false, fn_item.sig.output),
syn::ReturnType::Type(_tok, ty) => match *ty {
syn::Type::Path(ref path) => {
let Some(last) = path.path.segments.last() else {
return Err(syn::Error::new(Span::call_site(), "empty Result type is not valid"));
};
// TODO this is terrible, macro returns a function and we call it?? there must be a
// better way!!!
let mut out = (
false,
ReturnType::Type(syn::Token![->](Span::call_site()), Box::new(Type::Path(path.clone())))
);
if last.ident == "Result" {
match &last.arguments {
syn::PathArguments::None => return Err(syn::Error::new(Span::call_site(), "Result without generics is not valid")),
syn::PathArguments::Parenthesized(_) => return Err(syn::Error::new(Span::call_site(), "Parenthesized Result is not valid")),
syn::PathArguments::AngleBracketed(ref generics) => for generic in generics.args.iter() {
match generic {
syn::GenericArgument::Lifetime(_) => continue,
syn::GenericArgument::Type(ty) => {
out = (true, ReturnType::Type(syn::Token![->](Span::call_site()), Box::new(ty.clone())));
break;
},
_ => return Err(syn::Error::new(Span::call_site(), "unexpected type in Result")),
}
}
}
}
out
},
_ => return Err(syn::Error::new(Span::call_site(), "unsupported return type")),
},
};
let ret = ReturnOptions::parse_signature(fn_item.sig.output.clone())?;
let mut incoming = TokenStream::new();
let mut forwarding = TokenStream::new();
for arg in fn_item.sig.inputs {
let FnArg::Typed(ty) = arg else {
return Err(syn::Error::new(Span::call_site(), "#[jni] macro doesn't work on methods"));
};
incoming.append_all(quote::quote!( #ty , ));
let pat = unpack_pat(*ty.pat)?;
forwarding.append_all(pat);
}
let return_type = ret.clone().tokens();
let name = fn_item.sig.ident.to_string();
let name_jni = name.replace("_", "_1");
let fn_name_inner = syn::Ident::new(&name, Span::call_site());
let fn_name = syn::Ident::new(&format!("Java_{}_{}_{name_jni}", attrs.package, attrs.class), Span::call_site());
let Some(env_ident) = forwarding.clone().into_iter().next() else {
return Err(syn::Error::new(Span::call_site(), "missing JNIEnv argument"));
let (incoming, forwarding) = parse_args(fn_item)?;
let header = quote::quote! {
#[no_mangle]
#[allow(unused_mut)]
pub extern "system" fn #fn_name<'local>(#incoming) #return_type
};
let return_expr = if attrs.return_pointer {
@ -79,13 +37,15 @@ pub(crate) fn generate_jni_wrapper(attrs: TokenStream, input: TokenStream) -> Re
quote::quote!( 0 )
};
let wrapped = if could_error {
let Some(env_ident) = forwarding.clone().into_iter().next() else {
return Err(syn::Error::new(Span::call_site(), "missing JNIEnv argument"));
};
let body = if ret.result { // wrap errors
if let Some(exception) = attrs.exception {
// V----------------------------------V
quote::quote! {
#[no_mangle]
#[allow(unused_mut)]
pub extern "system" fn #fn_name<'local>(#incoming) #ret_type {
{
use jni_toolbox::JniToolboxError;
match #fn_name_inner(#forwarding) {
Ok(ret) => ret,
@ -100,9 +60,7 @@ pub(crate) fn generate_jni_wrapper(attrs: TokenStream, input: TokenStream) -> Re
} else {
// V----------------------------------V
quote::quote! {
#[no_mangle]
#[allow(unused_mut)]
pub extern "system" fn #fn_name<'local>(#incoming) #ret_type {
{
use jni_toolbox::JniToolboxError;
// NOTE: this is SAFE! the cloned env reference lives less than the actual one, we just lack a
// way to get it back from the called function and thus resort to unsafe cloning
@ -125,14 +83,11 @@ pub(crate) fn generate_jni_wrapper(attrs: TokenStream, input: TokenStream) -> Re
}
}
}
// ^----------------------------------^
}
} else {
// V----------------------------------V
quote::quote! {
#[no_mangle]
#[allow(unused_mut)]
pub extern "system" fn #fn_name<'local>(#incoming) #ret_type {
{
#fn_name_inner(#forwarding)
}
}
@ -140,19 +95,7 @@ pub(crate) fn generate_jni_wrapper(attrs: TokenStream, input: TokenStream) -> Re
};
out.append_all(input);
out.append_all(wrapped);
out.append_all(header);
out.append_all(body);
Ok(out)
}
fn unpack_pat(pat: syn::Pat) -> Result<TokenStream, syn::Error> {
match pat {
syn::Pat::Ident(i) => {
let ident = i.ident;
Ok(quote::quote!( #ident ,))
},
syn::Pat::Reference(r) => {
unpack_pat(*r.pat)
},
_ => Err(syn::Error::new(Span::call_site(), "unsupported argument type")),
}
}