ledger-tool: Minor cleanup on accountsdb config argument parsing (#34671)

- Avoid repeated parsing + use of values_t_or_exit!()
- Move associated items closer to show grouping

ledger-tool/src/args.rs

@@ -1,6 +1,6 @@
 use {
     crate::LEDGER_TOOL_DIRECTORY,
-    clap::{value_t, values_t_or_exit, ArgMatches},
+    clap::{value_t, values_t, values_t_or_exit, ArgMatches},
     solana_accounts_db::{
         accounts_db::{AccountsDb, AccountsDbConfig},
         accounts_index::{AccountsIndexConfig, IndexLimitMb},
@@ -20,6 +20,7 @@ pub fn get_accounts_db_config(
     arg_matches: &ArgMatches<'_>,
 ) -> AccountsDbConfig {
     let ledger_tool_ledger_path = ledger_path.join(LEDGER_TOOL_DIRECTORY);
+
     let accounts_index_bins = value_t!(arg_matches, "accounts_index_bins", usize).ok();
     let accounts_index_index_limit_mb =
         if let Ok(limit) = value_t!(arg_matches, "accounts_index_memory_limit_mb", usize) {
@@ -29,6 +30,17 @@ pub fn get_accounts_db_config(
         } else {
             IndexLimitMb::Unspecified
         };
+    let accounts_index_drives = values_t!(arg_matches, "accounts_index_path", String)
+        .ok()
+        .map(|drives| drives.into_iter().map(PathBuf::from).collect())
+        .unwrap_or_else(|| vec![ledger_tool_ledger_path.join("accounts_index")]);
+    let accounts_index_config = AccountsIndexConfig {
+        bins: accounts_index_bins,
+        index_limit_mb: accounts_index_index_limit_mb,
+        drives: Some(accounts_index_drives),
+        ..AccountsIndexConfig::default()
+    };
+
     let test_partitioned_epoch_rewards =
         if arg_matches.is_present("partitioned_epoch_rewards_compare_calculation") {
             TestPartitionedEpochRewards::CompareResults
@@ -38,21 +50,6 @@ pub fn get_accounts_db_config(
             TestPartitionedEpochRewards::None
         };
 
-    let accounts_index_drives: Vec<PathBuf> = if arg_matches.is_present("accounts_index_path") {
-        values_t_or_exit!(arg_matches, "accounts_index_path", String)
-            .into_iter()
-            .map(PathBuf::from)
-            .collect()
-    } else {
-        vec![ledger_tool_ledger_path.join("accounts_index")]
-    };
-    let accounts_index_config = AccountsIndexConfig {
-        bins: accounts_index_bins,
-        index_limit_mb: accounts_index_index_limit_mb,
-        drives: Some(accounts_index_drives),
-        ..AccountsIndexConfig::default()
-    };
-
     let accounts_hash_cache_path = arg_matches
         .value_of("accounts_hash_cache_path")
         .map(Into::into)