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use crate::ItemImplInfo;
use quote::quote;
use syn::export::{ToTokens, TokenStream2};
use syn::visit::Visit;
use syn::{Error, ItemImpl};
#[derive(Default)]
pub struct MetadataVisitor {
impl_item_infos: Vec<ItemImplInfo>,
errors: Vec<Error>,
}
impl<'ast> Visit<'ast> for MetadataVisitor {
fn visit_item_impl(&mut self, i: &'ast ItemImpl) {
let has_near_sdk_attr = i
.attrs
.iter()
.any(|attr| attr.path.to_token_stream().to_string().as_str() == "near_bindgen");
if has_near_sdk_attr {
match ItemImplInfo::new(&mut i.clone()) {
Ok(info) => self.impl_item_infos.push(info),
Err(err) => self.errors.push(err),
}
}
syn::visit::visit_item_impl(self, i);
}
}
impl MetadataVisitor {
pub fn new() -> Self {
Default::default()
}
pub fn generate_metadata_method(&self) -> syn::Result<TokenStream2> {
if !self.errors.is_empty() {
return Err(self.errors[0].clone());
}
let panic_hook = quote! {
near_sdk::env::setup_panic_hook();
};
let env_creation = quote! {
near_sdk::env::set_blockchain_interface(Box::new(near_blockchain::NearBlockchain {}));
};
let methods: Vec<TokenStream2> = self
.impl_item_infos
.iter()
.flat_map(|i| &i.methods)
.map(|m| m.metadata_struct())
.collect();
Ok(quote! {
#[cfg(target_arch = "wasm32")]
#[no_mangle]
pub extern "C" fn metadata() {
#panic_hook
#env_creation
use borsh::*;
let metadata = near_sdk::Metadata::new(vec![
#(#methods),*
]);
let data = borsh::BorshSerialize::try_to_vec(&metadata).expect("Failed to serialize the metadata using Borsh");
near_sdk::env::value_return(&data);
}
})
}
}
#[rustfmt::skip]
#[cfg(test)]
mod tests {
use quote::quote;
use super::*;
#[test]
fn several_methods() {
let code = quote! {
#[near_bindgen]
impl Hello {
pub fn f1(&self) { }
pub fn f2(&mut self, arg0: FancyStruct, arg1: u64) { }
}
#[near_bindgen]
impl SomeTrait for Hello {
fn f3(&mut self, arg0: FancyStruct, arg1: u64) -> Result<IsOk, Error> { }
}
};
let file: syn::File = syn::parse2(code).unwrap();
let mut visitor = MetadataVisitor::new();
visitor.visit_file(&file);
let actual = visitor.generate_metadata_method().unwrap();
let expected = quote!(
#[cfg(target_arch = "wasm32")]
#[no_mangle]
pub extern "C" fn metadata() {
near_sdk::env::setup_panic_hook();
near_sdk::env::set_blockchain_interface(Box::new(near_blockchain::NearBlockchain {}));
use borsh::*;
let metadata = near_sdk::Metadata::new(vec![
near_sdk::MethodMetadata {
name: "f1".to_string(),
is_view: true,
is_init: false,
args: None,
callbacks: vec![],
callbacks_vec: None,
result: None
},
near_sdk::MethodMetadata {
name: "f2".to_string(),
is_view: false,
is_init: false,
args: {
#[derive(borsh::BorshSchema)]
#[derive(serde :: Deserialize, serde :: Serialize)]
struct Input {
arg0: FancyStruct,
arg1: u64,
}
Some(Input::schema_container())
},
callbacks: vec![],
callbacks_vec: None,
result: None
},
near_sdk::MethodMetadata {
name: "f3".to_string(),
is_view: false,
is_init: false,
args: {
#[derive(borsh::BorshSchema)]
#[derive(serde :: Deserialize, serde :: Serialize)]
struct Input {
arg0: FancyStruct,
arg1: u64,
}
Some(Input::schema_container())
},
callbacks: vec![],
callbacks_vec: None,
result: Some(Result < IsOk, Error > ::schema_container())
}
]);
let data = borsh::BorshSerialize::try_to_vec(&metadata)
.expect("Failed to serialize the metadata using Borsh");
near_sdk::env::value_return(&data);
}
);
assert_eq!(expected.to_string(), actual.to_string());
}
}