Allow short contract IDs (#49)

Co-authored-by: Leigh McCulloch <351529+leighmcculloch@users.noreply.github.com>

src/deploy.rs

@@ -3,7 +3,7 @@ use std::{fmt::Debug, fs, io};
 use clap::Parser;
 use soroban_env_host::xdr::Error as XdrError;
 
-use hex::{FromHex, FromHexError};
+use hex::FromHexError;
 
 use crate::snapshot;
 use crate::utils;
@@ -35,7 +35,7 @@ pub enum Error {
 
 impl Cmd {
     pub fn run(&self) -> Result<(), Error> {
-        let contract_id: [u8; 32] = FromHex::from_hex(&self.contract_id)?;
+        let contract_id: [u8; 32] = utils::contract_id_from_str(&self.contract_id)?;
         let contract = fs::read(&self.file).unwrap();
 
         let mut ledger_entries = snapshot::read(&self.snapshot_file)?;

src/invoke.rs

@@ -11,7 +11,7 @@ use soroban_env_host::{
     Host, HostError, Vm,
 };
 
-use hex::{FromHex, FromHexError};
+use hex::FromHexError;
 
 use crate::snapshot;
 use crate::strval::{self, StrValError};
@@ -67,7 +67,7 @@ pub enum Error {
 
 impl Cmd {
     pub fn run(&self) -> Result<(), Error> {
-        let contract_id: [u8; 32] = FromHex::from_hex(&self.contract_id)?;
+        let contract_id: [u8; 32] = utils::contract_id_from_str(&self.contract_id)?;
 
         // Initialize storage and host
         // TODO: allow option to separate input and output file

src/utils.rs

@@ -1,3 +1,4 @@
+use hex::FromHexError;
 use soroban_env_host::{
     im_rc::OrdMap,
     storage::Storage,
@@ -34,6 +35,13 @@ pub fn add_contract_to_ledger_entries(
     Ok(())
 }
 
+pub fn contract_id_from_str(contract_id: &String) -> Result<[u8; 32], FromHexError> {
+    let mut decoded = [0u8; 32];
+    let padded = format!("{:0>width$}", contract_id, width = decoded.len() * 2);
+    hex::decode_to_slice(padded, &mut decoded)?;
+    Ok(decoded)
+}
+
 pub fn get_contract_wasm_from_storage(
     storage: &mut Storage,
     contract_id: [u8; 32],