solana[WIP]: Refactor to reduce code duplication

Author: nvsriram

solana/programs/example-native-token-transfers/src/instructions/initialize.rs

@@ -37,12 +37,7 @@ pub struct Initialize<'info> {
     )]
     pub config: Box<Account<'info, crate::config::Config>>,
 
-    #[account(
-        constraint =
-            args.mode == Mode::Locking
-            || mint.mint_authority.unwrap() == token_authority.key()
-            @ NTTError::InvalidMintAuthority,
-    )]
+    #[account()]
     pub mint: Box<InterfaceAccount<'info, token_interface::Mint>>,
 
     #[account(
@@ -95,25 +90,79 @@ pub struct InitializeArgs {
     pub mode: ntt_messages::mode::Mode,
 }
 
-pub fn initialize(ctx: Context<Initialize>, args: InitializeArgs) -> Result<()> {
-    ctx.accounts.config.set_inner(crate::config::Config {
-        bump: ctx.bumps.config,
-        mint: ctx.accounts.mint.key(),
-        token_program: ctx.accounts.token_program.key(),
-        mode: args.mode,
-        chain_id: ChainId { id: args.chain_id },
-        owner: ctx.accounts.deployer.key(),
+#[derive(Accounts)]
+#[instruction(args: InitializeArgs)]
+pub struct InitializeDefault<'info> {
+    #[account(
+        constraint =
+            args.mode == Mode::Locking
+            || common.mint.mint_authority.unwrap() == common.token_authority.key()
+            @ NTTError::InvalidMintAuthority,
+    )]
+    pub common: Initialize<'info>,
+}
+
+pub fn initialize(ctx: Context<InitializeDefault>, args: InitializeArgs) -> Result<()> {
+    initialize_config_and_rate_limit(
+        &mut ctx.accounts.common,
+        ctx.bumps.common.config,
+        args.chain_id,
+        args.limit,
+        args.mode,
+    )
+}
+
+#[derive(Accounts)]
+#[instruction(args: InitializeArgs)]
+pub struct InitializeMultisig<'info> {
+    #[account(
+        constraint =
+            args.mode == Mode::Locking
+            || common.mint.mint_authority.unwrap() == multisig.key()
+            @ NTTError::InvalidMintAuthority,
+    )]
+    pub common: Initialize<'info>,
+
+    #[account()]
+    /// CHECK: multisig is mint authority
+    pub multisig: UncheckedAccount<'info>,
+}
+
+pub fn initialize_multisig(ctx: Context<InitializeMultisig>, args: InitializeArgs) -> Result<()> {
+    initialize_config_and_rate_limit(
+        &mut ctx.accounts.common,
+        ctx.bumps.common.config,
+        args.chain_id,
+        args.limit,
+        args.mode,
+    )
+}
+
+fn initialize_config_and_rate_limit(
+    common: &mut Initialize<'_>,
+    config_bump: u8,
+    chain_id: u16,
+    limit: u64,
+    mode: ntt_messages::mode::Mode,
+) -> Result<()> {
+    common.config.set_inner(crate::config::Config {
+        bump: config_bump,
+        mint: common.mint.key(),
+        token_program: common.token_program.key(),
+        mode,
+        chain_id: ChainId { id: chain_id },
+        owner: common.deployer.key(),
         pending_owner: None,
         paused: false,
         next_transceiver_id: 0,
         // NOTE: can't be changed for now
         threshold: 1,
         enabled_transceivers: Bitmap::new(),
-        custody: ctx.accounts.custody.key(),
+        custody: common.custody.key(),
     });
 
-    ctx.accounts.rate_limit.set_inner(OutboxRateLimit {
-        rate_limit: RateLimitState::new(args.limit),
+    common.rate_limit.set_inner(OutboxRateLimit {
+        rate_limit: RateLimitState::new(limit),
     });
 
     Ok(())

solana/programs/example-native-token-transfers/src/instructions/mod.rs

@@ -1,19 +1,15 @@
 pub mod admin;
 pub mod initialize;
-pub mod initialize_multisig;
 pub mod luts;
 pub mod mark_outbox_item_as_released;
 pub mod redeem;
 pub mod release_inbound;
-pub mod release_inbound_multisig;
 pub mod transfer;
 
 pub use admin::*;
 pub use initialize::*;
-pub use initialize_multisig::*;
 pub use luts::*;
 pub use mark_outbox_item_as_released::*;
 pub use redeem::*;
 pub use release_inbound::*;
-pub use release_inbound_multisig::*;
 pub use transfer::*;

solana/programs/example-native-token-transfers/src/instructions/release_inbound.rs

@@ -1,3 +1,5 @@
+use std::ops::{Deref, DerefMut};
+
 use anchor_lang::prelude::*;
 use anchor_spl::token_interface;
 use ntt_messages::mode::Mode;
@@ -66,6 +68,34 @@ pub struct ReleaseInboundMint<'info> {
     common: ReleaseInbound<'info>,
 }
 
+impl<'info> Deref for ReleaseInboundMint<'info> {
+    type Target = ReleaseInbound<'info>;
+
+    fn deref(&self) -> &Self::Target {
+        &self.common
+    }
+}
+
+impl Deref for ReleaseInboundMintBumps {
+    type Target = ReleaseInboundBumps;
+
+    fn deref(&self) -> &Self::Target {
+        &self.common
+    }
+}
+
+impl<'info> DerefMut for ReleaseInboundMint<'info> {
+    fn deref_mut(&mut self) -> &mut Self::Target {
+        &mut self.common
+    }
+}
+
+#[derive(Accounts)]
+pub struct ReleaseInboundMintDefault<'info> {
+    #[account(constraint = common.mint.mint_authority.unwrap() == common.token_authority.key())]
+    common: ReleaseInboundMint<'info>,
+}
+
 /// Release an inbound transfer and mint the tokens to the recipient.
 /// When `revert_on_error` is true, the transaction will revert if the
 /// release timestamp has not been reached. When `revert_on_error` is false, the
@@ -74,23 +104,9 @@ pub struct ReleaseInboundMint<'info> {
 /// together with [`crate::instructions::redeem`] in a transaction, so that the minting
 /// is attempted optimistically.
 pub fn release_inbound_mint<'info>(
-    ctx: Context<'_, '_, '_, 'info, ReleaseInboundMint<'info>>,
+    ctx: Context<'_, '_, '_, 'info, ReleaseInboundMintDefault<'info>>,
     args: ReleaseInboundArgs,
 ) -> Result<()> {
-    let inbox_item = &mut ctx.accounts.common.inbox_item;
-
-    let released = inbox_item.try_release()?;
-
-    if !released {
-        if args.revert_on_delay {
-            return Err(NTTError::CantReleaseYet.into());
-        } else {
-            return Ok(());
-        }
-    }
-
-    assert!(inbox_item.release_status == ReleaseStatus::Released);
-
     // NOTE: minting tokens is a two-step process:
     // 1. Mint tokens to the custody account
     // 2. Transfer the tokens from the custody account to the recipient
@@ -120,7 +136,7 @@ pub fn release_inbound_mint<'info>(
                 &[ctx.bumps.common.token_authority],
             ]],
         ),
-        inbox_item.amount,
+        ctx.accounts.common.inbox_item.amount,
     )?;
 
     // Step 2: transfer the tokens from the custody account to the recipient
@@ -131,13 +147,100 @@ pub fn release_inbound_mint<'info>(
         ctx.accounts.common.recipient.to_account_info(),
         ctx.accounts.common.token_authority.to_account_info(),
         ctx.remaining_accounts,
-        inbox_item.amount,
+        ctx.accounts.common.inbox_item.amount,
+        ctx.accounts.common.mint.decimals,
+        &[&[
+            crate::TOKEN_AUTHORITY_SEED,
+            &[ctx.bumps.common.token_authority],
+        ]],
+    )?;
+
+    release_inbox_item(&mut ctx.accounts.common.inbox_item, args.revert_on_delay)
+}
+
+#[derive(Accounts)]
+pub struct ReleaseInboundMintMultisig<'info> {
+    #[account(constraint = common.mint.mint_authority.unwrap() == multisig.key())]
+    common: ReleaseInboundMint<'info>,
+
+    /// CHECK: multisig account should be mint authority
+    pub multisig: UncheckedAccount<'info>,
+}
+
+pub fn release_inbound_mint_multisig<'info>(
+    ctx: Context<'_, '_, '_, 'info, ReleaseInboundMintMultisig<'info>>,
+    args: ReleaseInboundArgs,
+) -> Result<()> {
+    // NOTE: minting tokens is a two-step process:
+    // 1. Mint tokens to the custody account
+    // 2. Transfer the tokens from the custody account to the recipient
+    //
+    // This is done to ensure that if the token has a transfer hook defined, it
+    // will be called after the tokens are minted.
+    // Unfortunately the Token2022 program doesn't trigger transfer hooks when
+    // minting tokens, so we have to do it "manually" via a transfer.
+    //
+    // If we didn't do this, transfer hooks could be bypassed by transferring
+    // the tokens out through NTT first, then back in to the intended recipient.
+    //
+    // The [`transfer_burn`] function operates in a similar way
+    // (transfer to custody from sender, *then* burn).
+
+    // Step 1: mint tokens to the custody account
+    let ix = spl_token_2022::instruction::mint_to(
+        &ctx.accounts.common.token_program.key(),
+        &ctx.accounts.common.mint.key(),
+        &ctx.accounts.common.custody.key(),
+        &ctx.accounts.multisig.key(),
+        &[&ctx.accounts.common.token_authority.key()],
+        ctx.accounts.common.inbox_item.amount,
+    )?;
+    solana_program::program::invoke_signed(
+        &ix,
+        &[
+            ctx.accounts.common.custody.to_account_info(),
+            ctx.accounts.common.mint.to_account_info(),
+            ctx.accounts.common.token_authority.to_account_info(),
+            ctx.accounts.multisig.to_account_info(),
+        ],
+        &[&[
+            crate::TOKEN_AUTHORITY_SEED,
+            &[ctx.bumps.common.token_authority],
+        ]],
+    )?;
+
+    // Step 2: transfer the tokens from the custody account to the recipient
+    onchain::invoke_transfer_checked(
+        &ctx.accounts.common.token_program.key(),
+        ctx.accounts.common.custody.to_account_info(),
+        ctx.accounts.common.mint.to_account_info(),
+        ctx.accounts.common.recipient.to_account_info(),
+        ctx.accounts.common.token_authority.to_account_info(),
+        ctx.remaining_accounts,
+        ctx.accounts.common.inbox_item.amount,
         ctx.accounts.common.mint.decimals,
         &[&[
             crate::TOKEN_AUTHORITY_SEED,
             &[ctx.bumps.common.token_authority],
         ]],
     )?;
+
+    release_inbox_item(&mut ctx.accounts.common.inbox_item, args.revert_on_delay)
+}
+
+fn release_inbox_item(inbox_item: &mut InboxItem, revert_on_delay: bool) -> Result<()> {
+    let released = inbox_item.try_release()?;
+
+    if !released {
+        if revert_on_delay {
+            return Err(NTTError::CantReleaseYet.into());
+        } else {
+            return Ok(());
+        }
+    }
+
+    assert!(inbox_item.release_status == ReleaseStatus::Released);
+
     Ok(())
 }
 

solana/programs/example-native-token-transfers/src/lib.rs

@@ -70,13 +70,13 @@ pub mod example_native_token_transfers {
 
     use super::*;
 
-    pub fn initialize(ctx: Context<Initialize>, args: InitializeArgs) -> Result<()> {
+    pub fn initialize(ctx: Context<InitializeDefault>, args: InitializeArgs) -> Result<()> {
         instructions::initialize(ctx, args)
     }
 
     pub fn initialize_multisig(
         ctx: Context<InitializeMultisig>,
-        args: InitializeMultisigArgs,
+        args: InitializeArgs,
     ) -> Result<()> {
         instructions::initialize_multisig(ctx, args)
     }
@@ -108,24 +108,24 @@ pub mod example_native_token_transfers {
     }
 
     pub fn release_inbound_mint<'info>(
-        ctx: Context<'_, '_, '_, 'info, ReleaseInboundMint<'info>>,
+        ctx: Context<'_, '_, '_, 'info, ReleaseInboundMintDefault<'info>>,
         args: ReleaseInboundArgs,
     ) -> Result<()> {
         instructions::release_inbound_mint(ctx, args)
     }
 
-    pub fn release_inbound_unlock<'info>(
-        ctx: Context<'_, '_, '_, 'info, ReleaseInboundUnlock<'info>>,
+    pub fn release_inbound_mint_multisig<'info>(
+        ctx: Context<'_, '_, '_, 'info, ReleaseInboundMintMultisig<'info>>,
         args: ReleaseInboundArgs,
     ) -> Result<()> {
-        instructions::release_inbound_unlock(ctx, args)
+        instructions::release_inbound_mint_multisig(ctx, args)
     }
 
-    pub fn release_inbound_multisig_mint<'info>(
-        ctx: Context<'_, '_, '_, 'info, ReleaseInboundMultisigMint<'info>>,
-        args: ReleaseInboundMultisigArgs,
+    pub fn release_inbound_unlock<'info>(
+        ctx: Context<'_, '_, '_, 'info, ReleaseInboundUnlock<'info>>,
+        args: ReleaseInboundArgs,
     ) -> Result<()> {
-        instructions::release_inbound_multisig_mint(ctx, args)
+        instructions::release_inbound_unlock(ctx, args)
     }
 
     pub fn transfer_ownership(ctx: Context<TransferOwnership>) -> Result<()> {