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use crate::codegen::program::common::*;
use crate::Program;
use heck::CamelCase;
use quote::quote;
pub fn generate(program: &Program) -> proc_macro2::TokenStream {
// Dispatch the state constructor.
let ctor_state_dispatch_arm = match &program.state {
None => quote! { /* no-op */ },
Some(state) => match state.ctor_and_anchor.is_some() {
false => quote! {},
true => {
let sighash_arr = sighash_ctor();
let sighash_tts: proc_macro2::TokenStream =
format!("{:?}", sighash_arr).parse().unwrap();
quote! {
#sighash_tts => {
__private::__state::__ctor(
program_id,
accounts,
ix_data,
)
}
}
}
},
};
// Dispatch the state impl instructions.
let state_dispatch_arms: Vec<proc_macro2::TokenStream> = match &program.state {
None => vec![],
Some(s) => s
.impl_block_and_methods
.as_ref()
.map(|(_impl_block, methods)| {
methods
.iter()
.map(|ix: &crate::StateIx| {
let ix_method_name: proc_macro2::TokenStream =
format!("__{}", ix.raw_method.sig.ident).parse().expect(
"Failed to parse ix method name with `__` as `TokenStream`",
);
let ix_name_camel: proc_macro2::TokenStream = ix
.raw_method
.sig
.ident
.to_string()
.as_str()
.to_camel_case()
.parse()
.expect(
"Failed to parse state ix method name in camel as `TokenStream`",
);
quote! {
instruction::state::#ix_name_camel::DISCRIMINATOR => {
__private::__state::#ix_method_name(
program_id,
accounts,
ix_data,
)
}
}
})
.collect()
})
.unwrap_or_default(),
};
// Dispatch all trait interface implementations.
let trait_dispatch_arms: Vec<proc_macro2::TokenStream> = match &program.state {
None => vec![],
Some(s) => s
.interfaces
.as_ref()
.map(|interfaces| {
interfaces
.iter()
.flat_map(|iface: &crate::StateInterface| {
iface
.methods
.iter()
.map(|m: &crate::StateIx| {
let sighash_arr = sighash(&iface.trait_name, &m.ident.to_string());
let sighash_tts: proc_macro2::TokenStream =
format!("{:?}", sighash_arr).parse().unwrap();
let name = &m.raw_method.sig.ident.to_string();
let ix_method_name: proc_macro2::TokenStream =
format!("__{}_{}", iface.trait_name, name).parse().unwrap();
quote! {
#sighash_tts => {
__private::__interface::#ix_method_name(
program_id,
accounts,
ix_data,
)
}
}
})
.collect::<Vec<proc_macro2::TokenStream>>()
})
.collect()
})
.unwrap_or_default(),
};
// Dispatch all global instructions.
let global_dispatch_arms: Vec<proc_macro2::TokenStream> = 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()
.as_str()
.to_camel_case()
.parse()
.expect("Failed to parse ix method name in camel as `TokenStream`");
quote! {
instruction::#ix_name_camel::DISCRIMINATOR => {
__private::__global::#ix_method_name(
program_id,
accounts,
ix_data,
)
}
}
})
.collect();
let fallback_fn = gen_fallback(program).unwrap_or(quote! {
Err(anchor_lang::error::ErrorCode::InstructionFallbackNotFound.into())
});
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 creater a method identifier,
/// specifically, Anchor uses
///
/// Sha256("<namespace>:<rust-identifier>")[..8],
///
/// where the namespace can be one of three types. 1) "global" for a
/// regular instruction, 2) "state" for a state struct instruction
/// handler and 3) a trait namespace (used in combination with the
/// `#[interface]` attribute), which is defined by the trait name, e..
/// `MyTrait`.
///
/// 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(
program_id: &Pubkey,
accounts: &[AccountInfo],
data: &[u8],
) -> anchor_lang::Result<()> {
// Split the instruction data into the first 8 byte method
// identifier (sighash) and the serialized instruction data.
let mut ix_data: &[u8] = data;
let sighash: [u8; 8] = {
let mut sighash: [u8; 8] = [0; 8];
sighash.copy_from_slice(&ix_data[..8]);
ix_data = &ix_data[8..];
sighash
};
// If the method identifier is the IDL tag, then execute an IDL
// instruction, injected into all Anchor programs.
if cfg!(not(feature = "no-idl")) {
if sighash == anchor_lang::idl::IDL_IX_TAG.to_le_bytes() {
return __private::__idl::__idl_dispatch(
program_id,
accounts,
&ix_data,
);
}
}
use anchor_lang::Discriminator;
match sighash {
#ctor_state_dispatch_arm
#(#state_dispatch_arms)*
#(#trait_dispatch_arms)*
#(#global_dispatch_arms)*
_ => {
#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)
}
})
}