move all constants

metadata/program/src/constants.rs

@@ -0,0 +1,15 @@
+/// A constant seed used for metadata-related operations.
+/// This is a byte slice with the value `"metadata"`.
+pub const METADATA_SEED: &[u8] = b"metadata";
+
+/// The maximum allowed length for a name in the metadata.
+/// This value is set to 32 characters.
+pub const MAX_NAME_LEN: usize = 32;
+
+/// The maximum allowed length for a symbol in the metadata.
+/// This value is set to 10 characters.
+pub const MAX_SYMBOL_LEN: usize = 10;
+
+/// The maximum allowed length for a URI in the metadata.
+/// This value is set to 200 characters.
+pub const MAX_URI_LEN: usize = 200;

metadata/program/src/lib.rs

@@ -1,8 +1,10 @@
+pub mod constants;
 pub mod entrypoint;
 pub mod error;
 pub mod instruction;
 pub mod processor;
 pub mod state;
+pub mod utils;
 
 // Defineing the program ID
 solana_program::declare_id!("metaAig5QsCBSfstkwqPQxzdjXdUB8JxjfvtvEPNe3F");

metadata/program/src/processor.rs

@@ -1,4 +1,10 @@
-use crate::{error::MetadataError, instruction::TokenInstruction, state::TokenMetadata};
+use crate::{
+    constants::{MAX_NAME_LEN, MAX_SYMBOL_LEN, MAX_URI_LEN, METADATA_SEED},
+    error::MetadataError,
+    instruction::TokenInstruction,
+    state::TokenMetadata,
+    utils::derive_metadata_pda,
+};
 
 use borsh::{BorshDeserialize, BorshSerialize};
 use solana_program::{
@@ -13,10 +19,6 @@ use solana_program::{
     sysvar::Sysvar,
 };
 
-const MAX_NAME_LEN: usize = 32;
-const MAX_SYMBOL_LEN: usize = 10;
-const MAX_URI_LEN: usize = 200;
-
 pub struct Processor;
 impl Processor {
     pub fn process(
@@ -84,8 +86,7 @@ impl Processor {
         }
 
         // Create PDA account
-        let (pda, bump_seed) =
-            Pubkey::find_program_address(&[b"metadata", mint_account.key.as_ref()], program_id);
+        let (pda, bump_seed) = derive_metadata_pda(mint_account.key, program_id);
         if pda != *metadata_account.key {
             return Err(MetadataError::InvalidPda.into());
         }
@@ -108,7 +109,7 @@ impl Processor {
                 metadata_account.clone(),
                 system_program.clone(),
             ],
-            &[&[b"metadata", mint_account.key.as_ref(), &[bump_seed]]],
+            &[&[METADATA_SEED, mint_account.key.as_ref(), &[bump_seed]]],
         )?;
 
         // Write metadata to the account
@@ -142,8 +143,7 @@ impl Processor {
         let authority = next_account_info(account_info_iter)?;
 
         // Check mint account
-        let (pda, _bump_seed) =
-            Pubkey::find_program_address(&[b"metadata", mint_account.key.as_ref()], program_id);
+        let (pda, _bump_seed) = derive_metadata_pda(mint_account.key, program_id);
         if pda != *metadata_account.key {
             return Err(MetadataError::InvalidPda.into());
         }

metadata/program/src/utils.rs

@@ -1,5 +1,7 @@
-use solana_program::{program_error::ProgramError, pubkey::Pubkey};
+use solana_program::pubkey::Pubkey;
+
+use crate::constants::METADATA_SEED;
 
 pub fn derive_metadata_pda(mint: &Pubkey, program_id: &Pubkey) -> (Pubkey, u8) {
-    Pubkey::find_program_address(&[b"metadata", mint.as_ref()], program_id)
+    Pubkey::find_program_address(&[METADATA_SEED, mint.as_ref()], program_id)
 }