program: Add custom errors

program/src/error.rs

@@ -4,6 +4,18 @@ use pinocchio::program_error::ProgramError;
 pub enum ProgramMetadataError {
     /// 0 - The program account is not executable.
     NotExecutableAccount,
+
+    /// 1 - The program state is invalid.
+    InvalidProgramState,
+
+    /// 2 - The program data account is invalid.
+    InvalidProgramDataAccount,
+
+    /// 3 - The metadata account is immutable.
+    ImmutableMetadataAccount,
+
+    /// 4 - The account data length is invalid.
+    InvalidDataLength,
 }
 
 impl From<ProgramMetadataError> for ProgramError {

program/src/processor/mod.rs

@@ -4,7 +4,10 @@ use pinocchio::{
     pubkey::{Pubkey, PUBKEY_BYTES},
 };
 
-use crate::state::{header::Header, Account, AccountDiscriminator};
+use crate::{
+    error::ProgramMetadataError,
+    state::{header::Header, Account, AccountDiscriminator},
+};
 
 pub mod allocate;
 pub mod close;
@@ -71,16 +74,14 @@ fn is_program_authority(
                     .map_err(|_| ProgramError::InvalidAccountData)?
             }
             _ => {
-                // TODO: use custom error (invalid program state)
-                return Err(ProgramError::InvalidAccountData);
+                return Err(ProgramMetadataError::InvalidProgramState.into());
             }
         }
     };
 
     // Program <-> Program Data check.
     if expected_program_data != *program_data.key() {
-        // TODO: use custom error (invalid program data account)
-        return Err(ProgramError::InvalidAccountData);
+        return Err(ProgramMetadataError::InvalidProgramDataAccount.into());
     }
 
     // Program Data checks.
@@ -101,8 +102,7 @@ fn is_program_authority(
                 }
             }
             _ => {
-                // TODO: use custom error (invalid program state)
-                return Err(ProgramError::InvalidAccountData);
+                return Err(ProgramMetadataError::InvalidProgramState.into());
             }
         }
     };
@@ -124,8 +124,7 @@ fn validate_metadata(metadata: &AccountInfo) -> Result<&Header, ProgramError> {
         return Err(ProgramError::UninitializedAccount);
     }
     if !header.mutable() {
-        // TODO: use custom error (immutable metadata account)
-        return Err(ProgramError::InvalidAccountData);
+        return Err(ProgramMetadataError::ImmutableMetadataAccount.into());
     }
     Ok(header)
 }

program/src/processor/set_immutable.rs

@@ -1,6 +1,6 @@
 use pinocchio::{account_info::AccountInfo, program_error::ProgramError, ProgramResult};
 
-use crate::state::header::Header;
+use crate::{error::ProgramMetadataError, state::header::Header};
 
 use super::{validate_authority, validate_metadata};
 
@@ -40,8 +40,7 @@ pub fn set_immutable(accounts: &[AccountInfo]) -> ProgramResult {
     if header.mutable() {
         header.mutable = 0;
     } else {
-        // TODO: use custom error (metadata already immutable)
-        return Err(ProgramError::InvalidAccountData);
+        return Err(ProgramMetadataError::ImmutableMetadataAccount.into());
     }
 
     Ok(())

program/src/state/mod.rs

@@ -11,6 +11,8 @@ use pinocchio::{
 use data::{Data, ExternalData};
 use header::Header;
 
+use crate::error::ProgramMetadataError;
+
 /// The length of the seed used to derive the metadata account address.
 pub const SEED_LEN: usize = 16;
 
@@ -176,10 +178,7 @@ impl DataSource {
         match (self, length) {
             (DataSource::Direct | DataSource::Url, l) if l > 0 => Ok(()),
             (DataSource::External, ExternalData::LEN) => Ok(()),
-            _ => {
-                // TODO: use custom error (invalid data length)
-                Err(ProgramError::InvalidAccountData)
-            }
+            _ => Err(ProgramMetadataError::InvalidDataLength.into()),
         }
     }
 }