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

88 lines
3.8 KiB
Rust

use crate::program_codegen::dispatch;
use crate::Program;
use heck::CamelCase;
use quote::quote;
pub fn generate(program: &Program) -> proc_macro2::TokenStream {
let name: proc_macro2::TokenStream = program.name.to_string().to_camel_case().parse().unwrap();
let fallback_maybe = dispatch::gen_fallback(program).unwrap_or(quote! {
Err(anchor_lang::error::ErrorCode::InstructionMissing.into())
});
quote! {
#[cfg(not(feature = "no-entrypoint"))]
anchor_lang::solana_program::entrypoint!(entry);
/// The Anchor codegen exposes a programming model where a user defines
/// a set of methods inside of a `#[program]` module in a way similar
/// to writing RPC request handlers. The macro then generates a bunch of
/// code wrapping these user defined methods into something that can be
/// executed on Solana.
///
/// These methods fall into one categorie for now.
///
/// Global methods - regular methods inside of the `#[program]`.
///
/// Care must be taken by the codegen to prevent collisions between
/// methods in these different namespaces. For this reason, Anchor uses
/// a variant of sighash to perform method dispatch, rather than
/// something like a simple enum variant discriminator.
///
/// The execution flow of the generated code can be roughly outlined:
///
/// * Start program via the entrypoint.
/// * Strip method identifier off the first 8 bytes of the instruction
/// data and invoke the identified method. The method identifier
/// is a variant of sighash. See docs.rs for `anchor_lang` for details.
/// * If the method identifier is an IDL identifier, execute the IDL
/// instructions, which are a special set of hardcoded instructions
/// baked into every Anchor program. Then exit.
/// * Otherwise, the method identifier is for a user defined
/// instruction, i.e., one of the methods in the user defined
/// `#[program]` module. Perform method dispatch, i.e., execute the
/// big match statement mapping method identifier to method handler
/// wrapper.
/// * Run the method handler wrapper. This wraps the code the user
/// actually wrote, deserializing the accounts, constructing the
/// context, invoking the user's code, and finally running the exit
/// routine, which typically persists account changes.
///
/// The `entry` function here, defines the standard entry to a Solana
/// program, where execution begins.
pub fn entry(program_id: &Pubkey, accounts: &[AccountInfo], data: &[u8]) -> anchor_lang::solana_program::entrypoint::ProgramResult {
try_entry(program_id, accounts, data).map_err(|e| {
e.log();
e.into()
})
}
fn try_entry(program_id: &Pubkey, accounts: &[AccountInfo], data: &[u8]) -> anchor_lang::Result<()> {
#[cfg(feature = "anchor-debug")]
{
msg!("anchor-debug is active");
}
if *program_id != ID {
return Err(anchor_lang::error::ErrorCode::DeclaredProgramIdMismatch.into());
}
if data.len() < 8 {
return #fallback_maybe;
}
dispatch(program_id, accounts, data)
}
/// Module representing the program.
pub mod program {
use super::*;
/// Type representing the program.
#[derive(Clone)]
pub struct #name;
impl anchor_lang::Id for #name {
fn id() -> Pubkey {
ID
}
}
}
}
}