program: use size_of() uniformly

program/src/instruction.rs

@@ -180,11 +180,11 @@ pub fn initialize(
     minimum_pool_balance: u64,
 ) -> Vec<Instruction> {
     let pool_address = find_pool_address(program_id, vote_account_address);
-    let pool_rent = rent.minimum_balance(std::mem::size_of::<SinglePool>());
+    let pool_rent = rent.minimum_balance(SinglePool::size_of());
 
     let stake_address = find_pool_stake_address(program_id, &pool_address);
     let onramp_address = find_pool_onramp_address(program_id, &pool_address);
-    let stake_space = std::mem::size_of::<stake::state::StakeStateV2>();
+    let stake_space = stake::state::StakeStateV2::size_of();
     let stake_rent = rent.minimum_balance(stake_space);
     let stake_rent_plus_minimum = stake_rent.saturating_add(minimum_pool_balance);
 
@@ -344,8 +344,7 @@ pub fn deposit_stake(
 /// Creates all necessary instructions to withdraw stake into a given stake
 /// account. If a new stake account is required, the user should first include
 /// `system_instruction::create_account` with account size
-/// `std::mem::size_of::<stake::state::StakeStateV2>()` and owner
-/// `stake::program::id()`.
+/// `stake::state::StakeStateV2::size_of()` and owner `stake::program::id()`.
 pub fn withdraw(
     program_id: &Pubkey,
     pool_address: &Pubkey,
@@ -438,7 +437,7 @@ pub fn create_and_delegate_user_stake(
     stake_amount: u64,
 ) -> Vec<Instruction> {
     let pool_address = find_pool_address(program_id, vote_account_address);
-    let stake_space = std::mem::size_of::<stake::state::StakeStateV2>();
+    let stake_space = stake::state::StakeStateV2::size_of();
     let lamports = rent
         .minimum_balance(stake_space)
         .saturating_add(stake_amount);
@@ -557,7 +556,7 @@ pub fn create_pool_onramp(
     rent: &Rent,
 ) -> Vec<Instruction> {
     let onramp_address = find_pool_onramp_address(program_id, pool_address);
-    let stake_space = std::mem::size_of::<stake::state::StakeStateV2>();
+    let stake_space = stake::state::StakeStateV2::size_of();
     let stake_rent = rent.minimum_balance(stake_space);
 
     vec![

program/src/processor.rs

@@ -18,7 +18,7 @@ use {
     },
     borsh::BorshDeserialize,
     solana_account_info::{next_account_info, AccountInfo},
-    solana_borsh::v1::{get_packed_len, try_from_slice_unchecked},
+    solana_borsh::v1::try_from_slice_unchecked,
     solana_clock::{Clock, Epoch},
     solana_cpi::invoke_signed,
     solana_msg::msg,
@@ -626,7 +626,7 @@ impl Processor {
         let mint_authority_signers = &[&mint_authority_seeds[..]];
 
         // create the pool. user has already transferred in rent
-        let pool_space = get_packed_len::<SinglePool>();
+        let pool_space = SinglePool::size_of();
         if !rent.is_exempt(pool_info.lamports(), pool_space) {
             return Err(SinglePoolError::WrongRentAmount.into());
         }
@@ -681,7 +681,7 @@ impl Processor {
         // create the pool stake account. user has already transferred in rent plus at
         // least the minimum
         let minimum_pool_balance = minimum_pool_balance()?;
-        let stake_space = std::mem::size_of::<stake::state::StakeStateV2>();
+        let stake_space = StakeStateV2::size_of();
         let stake_rent_plus_initial = rent
             .minimum_balance(stake_space)
             .saturating_add(minimum_pool_balance);
@@ -1411,7 +1411,7 @@ impl Processor {
         let stake_authority_signers = &[&stake_authority_seeds[..]];
 
         // create the pool on-ramp account. user has already transferred in rent
-        let stake_space = std::mem::size_of::<stake::state::StakeStateV2>();
+        let stake_space = StakeStateV2::size_of();
         let stake_rent = rent.minimum_balance(stake_space);
 
         if pool_onramp_info.lamports() < stake_rent {

program/src/state.rs

@@ -28,6 +28,11 @@ pub struct SinglePool {
     pub vote_account_address: Pubkey,
 }
 impl SinglePool {
+    /// Onchain serialized size of `SinglePool`
+    pub const fn size_of() -> usize {
+        33
+    }
+
     /// Create a `SinglePool` struct from its account info
     pub fn from_account_info(
         account_info: &AccountInfo,
@@ -55,3 +60,13 @@ impl SinglePool {
         Ok(pool)
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use {super::*, solana_borsh::v1::get_packed_len};
+
+    #[test]
+    fn single_pool_size_of() {
+        assert_eq!(SinglePool::size_of(), get_packed_len::<SinglePool>());
+    }
+}