anchor/lang/syn/src/codegen/program/dispatch.rs

109 lines
3.9 KiB
Rust

use crate::Program;
use heck::CamelCase;
use quote::quote;
pub fn generate(program: &Program) -> proc_macro2::TokenStream {
// Dispatch all global instructions.
let global_ixs = program.ixs.iter().map(|ix| {
let ix_method_name = &ix.raw_method.sig.ident;
let ix_name_camel: proc_macro2::TokenStream = ix_method_name
.to_string()
.to_camel_case()
.parse()
.expect("Failed to parse ix method name in camel as `TokenStream`");
let discriminator = quote! { instruction::#ix_name_camel::DISCRIMINATOR };
quote! {
if data.starts_with(#discriminator) {
return __private::__global::#ix_method_name(
program_id,
accounts,
&data[#discriminator.len()..],
)
}
}
});
let fallback_fn = gen_fallback(program).unwrap_or(quote! {
Err(anchor_lang::error::ErrorCode::InstructionFallbackNotFound.into())
});
let event_cpi_handler = generate_event_cpi_handler();
quote! {
/// Performs method dispatch.
///
/// Each method in an anchor program is uniquely defined by a namespace
/// and a rust identifier (i.e., the name given to the method). These
/// two pieces can be combined to create a method identifier,
/// specifically, Anchor uses
///
/// Sha256("<namespace>:<rust-identifier>")[..8],
///
/// where the namespace can be one type. "global" for a
/// regular instruction.
///
/// With this 8 byte identifier, Anchor performs method dispatch,
/// matching the given 8 byte identifier to the associated method
/// handler, which leads to user defined code being eventually invoked.
fn dispatch<'info>(
program_id: &Pubkey,
accounts: &'info [AccountInfo<'info>],
data: &[u8],
) -> anchor_lang::Result<()> {
#(#global_ixs)*
// Dispatch IDL instructions
if data.starts_with(anchor_lang::idl::IDL_IX_TAG_LE) {
// If the method identifier is the IDL tag, then execute an IDL
// instruction, injected into all Anchor programs unless they have
// `no-idl` feature enabled
#[cfg(not(feature = "no-idl"))]
return __private::__idl::__idl_dispatch(
program_id,
accounts,
&data[anchor_lang::idl::IDL_IX_TAG_LE.len()..],
);
#[cfg(feature = "no-idl")]
return Err(anchor_lang::error::ErrorCode::IdlInstructionStub.into());
}
// Dispatch Event CPI instruction
if data.starts_with(anchor_lang::event::EVENT_IX_TAG_LE) {
return #event_cpi_handler;
}
#fallback_fn
}
}
}
pub fn gen_fallback(program: &Program) -> Option<proc_macro2::TokenStream> {
program.fallback_fn.as_ref().map(|fallback_fn| {
let program_name = &program.name;
let method = &fallback_fn.raw_method;
let fn_name = &method.sig.ident;
quote! {
#program_name::#fn_name(program_id, accounts, data)
}
})
}
/// Generate the event-cpi instruction handler based on whether the `event-cpi` feature is enabled.
pub fn generate_event_cpi_handler() -> proc_macro2::TokenStream {
#[cfg(feature = "event-cpi")]
quote! {
// `event-cpi` feature is enabled, dispatch self-cpi instruction
__private::__events::__event_dispatch(
program_id,
accounts,
&data[anchor_lang::event::EVENT_IX_TAG_LE.len()..]
)
}
#[cfg(not(feature = "event-cpi"))]
quote! {
// `event-cpi` feature is not enabled
Err(anchor_lang::error::ErrorCode::EventInstructionStub.into())
}
}