improve: binary encoding for wallet data

src/wallet/api.rs

@@ -498,14 +498,8 @@
         prevout: OutPoint,
         contract: ScriptBuf,
     ) -> Result<(), WalletError> {
-        // let mut wallet_file_data = Wallet::load_wallet_file_data(&self.wallet_file_path[..])?;
-        // wallet_file_data
-        //     .prevout_to_contract_map
-        //     .insert(prevout, contract);
-        // let wallet_file = File::create(&self.wallet_file_path[..])?;
-        // serde_json::to_writer(wallet_file, &wallet_file_data).map_err(|e| io::Error::from(e))?;
         if let Some(contract) = self.store.prevout_to_contract_map.insert(prevout, contract) {
-            log::debug!(target: "Wallet:cache_prevout_to_contract", "prevout-contract map updated. existing contract: {}", contract);
+            log::debug!(target: "Wallet:cache_prevout_to_contract", "prevout-contract map updated.\nExisting contract: {}", contract);
         }
         Ok(())
     }

src/wallet/error.rs

@@ -6,7 +6,7 @@
 #[derive(Debug)]
 pub enum WalletError {
     File(std::io::Error),
-    Json(serde_json::Error),
+    Cbor(serde_cbor::Error),
     Rpc(bitcoind::bitcoincore_rpc::Error),
     Protocol(String),
     BIP32(bitcoin::bip32::Error),
@@ -20,12 +20,6 @@
     }
 }
 
-impl From<serde_json::Error> for WalletError {
-    fn from(e: serde_json::Error) -> Self {
-        Self::File(e.into())
-    }
-}
-
 impl From<bitcoind::bitcoincore_rpc::Error> for WalletError {
     fn from(value: bitcoind::bitcoincore_rpc::Error) -> Self {
         Self::Rpc(value)
@@ -49,3 +43,9 @@
         Self::Contract(value)
     }
 }
+
+impl From<serde_cbor::Error> for WalletError {
+    fn from(value: serde_cbor::Error) -> Self {
+        Self::Cbor(value)
+    }
+}

src/wallet/storage.rs

@@ -1,12 +1,16 @@
 //! The Wallet Storage Interface.
 //!
-//! Wallet data are currently written in a readable, unencrypted json file.
+//! Wallet data is currently written in unencrypted CBOR files which are not directly human readable.
 
-use std::{collections::HashMap, convert::TryFrom, io::Read, path::PathBuf};
+use std::{collections::HashMap, convert::TryFrom, path::PathBuf};
 
 use bip39::Mnemonic;
 use bitcoin::{bip32::ExtendedPrivKey, Network, OutPoint, ScriptBuf};
-use std::fs::{File, OpenOptions};
+use serde::{Deserialize, Serialize};
+use std::{
+    fs::{File, OpenOptions},
+    io::{BufReader, BufWriter},
+};
 
 use super::{error::WalletError, SwapCoin};
 
@@ -16,7 +20,7 @@ use super::fidelity::generate_fidelity_scripts;
 
 const WALLET_FILE_VERSION: u32 = 0;
 
-#[derive(serde::Serialize, serde::Deserialize)]
+#[derive(Serialize, Deserialize)]
 struct FileData {
     file_name: String,
     version: u32,
@@ -34,7 +38,7 @@ struct FileData {
 pub struct WalletStore {
     /// The file name associated with the wallet store.
     pub(crate) file_name: String,
-    /// The network the wallet operates on.
+    /// Network the wallet operates on.
     pub(crate) network: Network,
     /// The master key for the wallet.
     pub(super) master_key: ExtendedPrivKey,
@@ -153,17 +157,17 @@ impl FileData {
 
     /// File path should exist.
     fn load_from_file(path: &PathBuf) -> Result<Self, WalletError> {
-        let mut wallet_file = File::open(path)?;
-        let mut wallet_file_str = String::new();
-        wallet_file.read_to_string(&mut wallet_file_str)?;
-        Ok(serde_json::from_str::<FileData>(&wallet_file_str)?)
+        let wallet_file = File::open(path)?;
+        let reader = BufReader::new(wallet_file);
+        Ok(serde_cbor::from_reader(reader)?)
     }
 
     // Overwrite existing file or create a new one.
     fn save_to_file(&self, path: &PathBuf) -> Result<(), WalletError> {
-        std::fs::create_dir_all(path.parent().expect("path should not be root"))?;
+        std::fs::create_dir_all(path.parent().expect("Path should NOT be root!"))?;
         let file = OpenOptions::new().write(true).create(true).open(path)?;
-        serde_json::to_writer(file, &self)?;
+        let writer = BufWriter::new(file);
+        serde_cbor::to_writer(writer, &self)?;
         Ok(())
     }
 }
@@ -178,7 +182,7 @@ mod tests {
     #[test]
     fn test_write_and_read_wallet_to_disk() {
         let temp_dir = tempdir().unwrap();
-        let file_path = temp_dir.path().join("test_wallet.json");
+        let file_path = temp_dir.path().join("test_wallet.cbor");
         let mnemonic = Mnemonic::generate(12).unwrap().to_string();
 
         let original_wallet_store = WalletStore::init(