82 lines
2.7 KiB
Rust
82 lines
2.7 KiB
Rust
extern crate proc_macro;
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use quote::quote;
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use syn::parse_macro_input;
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/// The event attribute allows a struct to be used with
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/// [emit!](./macro.emit.html) so that programs can log significant events in
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/// their programs that clients can subscribe to. Currently, this macro is for
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/// structs only.
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#[proc_macro_attribute]
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pub fn event(
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_args: proc_macro::TokenStream,
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input: proc_macro::TokenStream,
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) -> proc_macro::TokenStream {
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let event_strct = parse_macro_input!(input as syn::ItemStruct);
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let event_name = &event_strct.ident;
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let discriminator: proc_macro2::TokenStream = {
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let discriminator =
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anchor_common::header::create_discriminator(&event_name.to_string(), Some("event"));
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format!("{:?}", discriminator).parse().unwrap()
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};
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let discriminator_trait_impl = {
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if cfg!(feature = "deprecated_layout") {
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quote! {
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fn discriminator() -> [u8; 8] {
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#discriminator
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}
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}
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} else {
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quote! {
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fn discriminator() -> [u8; 4] {
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#discriminator
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}
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}
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}
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};
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proc_macro::TokenStream::from(quote! {
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#[derive(anchor_lang::__private::EventIndex, AnchorSerialize, AnchorDeserialize)]
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#event_strct
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impl anchor_lang::Event for #event_name {
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fn data(&self) -> Vec<u8> {
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let mut d = #discriminator.to_vec();
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d.append(&mut self.try_to_vec().unwrap());
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d
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}
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}
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impl anchor_lang::Discriminator for #event_name {
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#discriminator_trait_impl
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}
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})
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}
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/// Creates an event that can be subscribed to by clients. Calling this method
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/// will internally borsh serialize the [event](./attr.event.html), base64
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/// encode the bytes, and then add a [msg!](../solana_program/macro.msg.html)
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/// log to the transaction.
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#[proc_macro]
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pub fn emit(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
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let data: proc_macro2::TokenStream = input.into();
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proc_macro::TokenStream::from(quote! {
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{
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let data = anchor_lang::Event::data(&#data);
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let msg_str = &anchor_lang::__private::base64::encode(data);
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anchor_lang::solana_program::msg!(msg_str);
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}
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})
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}
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// EventIndex is a marker macro. It functionally does nothing other than
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// allow one to mark fields with the `#[index]` inert attribute, which is
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// used to add metadata to IDLs.
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#[proc_macro_derive(EventIndex, attributes(index))]
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pub fn derive_event(_item: proc_macro::TokenStream) -> proc_macro::TokenStream {
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proc_macro::TokenStream::from(quote! {})
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}
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