Move get_bank_forks() into ledger/ so its available for use by ledger-tool/ (#6720)

ledger/src/bank_forks.rs

@@ -292,8 +292,8 @@ impl BankForks {
             .retain(|slot, _| slot == &root || descendants[&root].contains(slot));
     }
 
-    pub fn set_snapshot_config(&mut self, snapshot_config: SnapshotConfig) {
-        self.snapshot_config = Some(snapshot_config);
+    pub fn set_snapshot_config(&mut self, snapshot_config: Option<SnapshotConfig>) {
+        self.snapshot_config = snapshot_config;
     }
 
     pub fn snapshot_config(&self) -> &Option<SnapshotConfig> {

ledger/src/bank_forks_utils.rs

@@ -0,0 +1,62 @@
+use crate::{
+    bank_forks::{BankForks, SnapshotConfig},
+    blocktree::Blocktree,
+    blocktree_processor::{self, BankForksInfo, BlocktreeProcessorError, ProcessOptions},
+    leader_schedule_cache::LeaderScheduleCache,
+    snapshot_utils,
+};
+use log::*;
+use solana_sdk::genesis_block::GenesisBlock;
+use std::{fs, sync::Arc};
+
+pub fn load(
+    genesis_block: &GenesisBlock,
+    blocktree: &Blocktree,
+    account_paths: Option<String>,
+    snapshot_config: Option<&SnapshotConfig>,
+    process_options: ProcessOptions,
+) -> Result<(BankForks, Vec<BankForksInfo>, LeaderScheduleCache), BlocktreeProcessorError> {
+    if let Some(snapshot_config) = snapshot_config.as_ref() {
+        info!(
+            "Initializing snapshot path: {:?}",
+            snapshot_config.snapshot_path
+        );
+        let _ = fs::remove_dir_all(&snapshot_config.snapshot_path);
+        fs::create_dir_all(&snapshot_config.snapshot_path)
+            .expect("Couldn't create snapshot directory");
+
+        let tar =
+            snapshot_utils::get_snapshot_tar_path(&snapshot_config.snapshot_package_output_path);
+        if tar.exists() {
+            info!("Loading snapshot package: {:?}", tar);
+            // Fail hard here if snapshot fails to load, don't silently continue
+            let deserialized_bank = snapshot_utils::bank_from_archive(
+                account_paths
+                    .clone()
+                    .expect("Account paths not present when booting from snapshot"),
+                &snapshot_config.snapshot_path,
+                &tar,
+            )
+            .expect("Load from snapshot failed");
+
+            return blocktree_processor::process_blocktree_from_root(
+                genesis_block,
+                blocktree,
+                Arc::new(deserialized_bank),
+                &process_options,
+            );
+        } else {
+            info!("Snapshot package does not exist: {:?}", tar);
+        }
+    } else {
+        info!("Snapshots disabled");
+    }
+
+    info!("Processing ledger from genesis");
+    blocktree_processor::process_blocktree(
+        &genesis_block,
+        &blocktree,
+        account_paths,
+        process_options,
+    )
+}

ledger/src/lib.rs

@@ -1,4 +1,5 @@
 pub mod bank_forks;
+pub mod bank_forks_utils;
 pub mod block_error;
 #[macro_use]
 pub mod blocktree;