feat: return Result for SpendBook trait methods. adds Error::SpendBoo…

…k enum
maidsafe · Jun 24, 2021 · 5bddb4c · 5bddb4c
1 parent 287a341
commit 5bddb4c
Show file tree

Hide file tree

Showing 3 changed files with 44 additions and 12 deletions.
diff --git a/examples/mint-repl/mint-repl.rs b/examples/mint-repl/mint-repl.rs
@@ -499,7 +499,7 @@ fn validate(mintinfo: &MintInfo) -> Result<()> {
     };
 
     match dbc.confirm_valid(mintinfo.mintnode()?.key_manager()) {
-        Ok(_) => match mintinfo.mintnode()?.is_spent(dbc.name()) {
+        Ok(_) => match mintinfo.mintnode()?.is_spent(dbc.name())? {
             true => println!("\nThis DBC is unspendable.  (valid but has already been spent)\n"),
             false => println!("\nThis DBC is spendable.   (valid and has not been spent)\n"),
         },

diff --git a/src/error.rs b/src/error.rs
@@ -61,4 +61,6 @@ pub enum Error {
     /// JSON serialisation error.
     #[error("JSON serialisation error:: {0}")]
     JsonSerialisation(#[from] serde_json::Error),
+    #[error("SpendBook error {0}")]
+    SpendBook(String),
 }
diff --git a/src/mint.rs b/src/mint.rs
@@ -28,8 +28,14 @@ pub type MintSignatures = BTreeMap<DbcContentHash, (PublicKeySet, NodeSignature)
 pub const GENESIS_DBC_INPUT: Hash = Hash([0u8; 32]);
 
 pub trait SpendBook: std::fmt::Debug + Clone + IntoIterator {
-    fn lookup(&self, dbc_hash: &DbcContentHash) -> Option<&DbcTransaction>;
-    fn log(&mut self, dbc_hash: DbcContentHash, transaction: DbcTransaction);
+    type Error: std::error::Error;
+
+    fn lookup(&self, dbc_hash: &DbcContentHash) -> Result<Option<&DbcTransaction>, Self::Error>;
+    fn log(
+        &mut self,
+        dbc_hash: DbcContentHash,
+        transaction: DbcTransaction,
+    ) -> Result<(), Self::Error>;
 }
 
 #[derive(Debug, Default, Clone, Serialize, Deserialize)]
@@ -38,12 +44,19 @@ pub struct SimpleSpendBook {
 }
 
 impl SpendBook for SimpleSpendBook {
-    fn lookup(&self, dbc_hash: &DbcContentHash) -> Option<&DbcTransaction> {
-        self.transactions.get(dbc_hash)
+    type Error = std::convert::Infallible;
+
+    fn lookup(&self, dbc_hash: &DbcContentHash) -> Result<Option<&DbcTransaction>, Self::Error> {
+        Ok(self.transactions.get(dbc_hash))
     }
 
-    fn log(&mut self, dbc_hash: DbcContentHash, transaction: DbcTransaction) {
+    fn log(
+        &mut self,
+        dbc_hash: DbcContentHash,
+        transaction: DbcTransaction,
+    ) -> Result<(), Self::Error> {
         self.transactions.insert(dbc_hash, transaction);
+        Ok(())
     }
 }
 
@@ -181,12 +194,18 @@ impl<K: KeyManager, S: SpendBook> Mint<K, S> {
             outputs: BTreeSet::from_iter(vec![content.hash()]),
         };
 
-        match self.spendbook.lookup(&GENESIS_DBC_INPUT) {
+        match self
+            .spendbook
+            .lookup(&GENESIS_DBC_INPUT)
+            .map_err(|e| Error::SpendBook(e.to_string()))?
+        {
             Some(tx) if tx != &transaction => return Err(Error::GenesisInputAlreadySpent),
             _ => (),
         }
 
-        self.spendbook.log(GENESIS_DBC_INPUT, transaction.clone());
+        self.spendbook
+            .log(GENESIS_DBC_INPUT, transaction.clone())
+            .map_err(|e| Error::SpendBook(e.to_string()))?;
         let transaction_sig = self
             .key_manager
             .sign(&transaction.hash())
@@ -204,8 +223,12 @@ impl<K: KeyManager, S: SpendBook> Mint<K, S> {
         ))
     }
 
-    pub fn is_spent(&self, dbc_hash: DbcContentHash) -> bool {
-        self.spendbook.lookup(&dbc_hash).is_some()
+    pub fn is_spent(&self, dbc_hash: DbcContentHash) -> Result<bool> {
+        Ok(self
+            .spendbook
+            .lookup(&dbc_hash)
+            .map_err(|e| Error::SpendBook(e.to_string()))?
+            .is_some())
     }
 
     pub fn key_manager(&self) -> &K {
@@ -237,7 +260,12 @@ impl<K: KeyManager, S: SpendBook> Mint<K, S> {
 
         // Validate that each input has not yet been spent.
         for input in inputs_belonging_to_mint.iter() {
-            if let Some(transaction) = self.spendbook.lookup(&input).cloned() {
+            if let Some(transaction) = self
+                .spendbook
+                .lookup(&input)
+                .map_err(|e| Error::SpendBook(e.to_string()))?
+                .cloned()
+            {
                 // This input has already been spent, return the spend transaction to the user
                 let transaction_sigs = self.sign_transaction(&transaction)?;
                 return Err(Error::DbcAlreadySpent {
@@ -255,7 +283,9 @@ impl<K: KeyManager, S: SpendBook> Mint<K, S> {
             .iter()
             .filter(|&i| inputs_belonging_to_mint.contains(&i.name()))
         {
-            self.spendbook.log(input.name(), transaction.clone());
+            self.spendbook
+                .log(input.name(), transaction.clone())
+                .map_err(|e| Error::SpendBook(e.to_string()))?;
         }
 
         Ok((transaction, transaction_sigs))