Let clients know when transactions failed

src/bank.rs

@@ -89,6 +89,10 @@ pub enum BankError {
     /// the `last_id` has been discarded.
     LastIdNotFound(Hash),
 
+    /// The bank has not seen a transaction with the given `Signature` or the transaction is
+    /// too old and has been discarded.
+    SignatureNotFound,
+
     /// Proof of History verification failed.
     LedgerVerificationFailed,
     /// Contract's transaction token balance does not equal the balance after the transaction
@@ -711,17 +715,18 @@ impl Bank {
         self.transaction_count.load(Ordering::Relaxed)
     }
 
+    pub fn get_signature_status(&self, signature: &Signature) -> Result<()> {
+        let last_ids_sigs = self.last_ids_sigs.read().unwrap();
+        for (_hash, (signatures, _)) in last_ids_sigs.iter() {
+            if let Some(res) = signatures.get(signature) {
+                return res.clone();
+            }
+        }
+        Err(BankError::SignatureNotFound)
+    }
+
     pub fn has_signature(&self, signature: &Signature) -> bool {
-        let last_ids_sigs = self
+        self.get_signature_status(signature) != Err(BankError::SignatureNotFound)
-            .last_ids_sigs
-            .read()
-            .expect("'last_ids_sigs' read lock");
-        for (_hash, signatures) in last_ids_sigs.iter() {
-            if signatures.0.contains_key(signature) {
-                return true;
-            }
-        }
-        false
     }
 
     /// Hash the `accounts` HashMap. This represents a validator's interpretation

src/rpc.rs

@@ -1,6 +1,6 @@
 //! The `rpc` module implements the Solana RPC interface.
 
-use bank::{Account, Bank};
+use bank::{Account, Bank, BankError};
 use bincode::deserialize;
 use bs58;
 use jsonrpc_core::*;
@@ -9,6 +9,7 @@ use service::Service;
 use signature::{Pubkey, Signature};
 use std::mem;
 use std::net::{SocketAddr, UdpSocket};
+use std::result;
 use std::sync::atomic::{AtomicBool, Ordering};
 use std::sync::Arc;
 use std::thread::{self, sleep, Builder, JoinHandle};
@@ -125,7 +126,9 @@ impl RpcSol for RpcSolImpl {
             return Err(Error::invalid_request());
         }
         let signature = Signature::new(&signature_vec);
-        meta.request_processor.get_signature_status(signature)
+        meta.request_processor
+            .get_signature_status(signature)
+            .map(|res| res.is_ok())
     }
     fn get_account_info(&self, meta: Self::Metadata, id: String) -> Result<Account> {
         let pubkey_vec = bs58::decode(id)
@@ -174,7 +177,7 @@ impl RpcSol for RpcSolImpl {
                 .get_signature_status(signature)
                 .map_err(|_| Error::internal_error())?;
 
-            if signature_status {
+            if signature_status.is_ok() {
                 return Ok(bs58::encode(signature).into_string());
             } else if now.elapsed().as_secs() > 5 {
                 return Err(Error::internal_error());
@@ -224,8 +227,8 @@ impl JsonRpcRequestProcessor {
         let id = self.bank.last_id();
         Ok(bs58::encode(id).into_string())
     }
-    fn get_signature_status(&self, signature: Signature) -> Result<bool> {
+    fn get_signature_status(&self, signature: Signature) -> Result<result::Result<(), BankError>> {
-        Ok(self.bank.has_signature(&signature))
+        Ok(self.bank.get_signature_status(&signature))
     }
     fn get_transaction_count(&self) -> Result<u64> {
         Ok(self.bank.transaction_count() as u64)