use {
    crate::{
        accounts_db::{AccountShrinkThreshold, AccountsDb},
        accounts_index::AccountSecondaryIndexes,
        bank::{Bank, BankSlotDelta, Builtins},
        hardened_unpack::{unpack_snapshot, ParallelSelector, UnpackError, UnpackedAppendVecMap},
        serde_snapshot::{
            bank_from_streams, bank_to_stream, SerdeStyle, SnapshotStorage, SnapshotStorages,
            SnapshotStreams,
        },
        shared_buffer_reader::{SharedBuffer, SharedBufferReader},
        snapshot_package::{
            AccountsPackage, AccountsPackagePre, AccountsPackageSendError, AccountsPackageSender,
        },
        sorted_storages::SortedStorages,
    },
    bincode::{config::Options, serialize_into},
    bzip2::bufread::BzDecoder,
    flate2::read::GzDecoder,
    lazy_static::lazy_static,
    log::*,
    rayon::{prelude::*, ThreadPool},
    regex::Regex,
    solana_measure::measure::Measure,
    solana_sdk::{clock::Slot, genesis_config::GenesisConfig, hash::Hash, pubkey::Pubkey},
    std::{
        cmp::{max, Ordering},
        collections::HashSet,
        fmt,
        fs::{self, File},
        io::{self, BufReader, BufWriter, Error as IoError, ErrorKind, Read, Seek, Write},
        path::{Path, PathBuf},
        process::{self, ExitStatus},
        str::FromStr,
        sync::Arc,
    },
    tar::Archive,
    tempfile::TempDir,
    thiserror::Error,
};

/// Common information about a snapshot archive
#[derive(PartialEq, Eq, Debug)]
struct SnapshotArchiveInfo {
    /// Path to the snapshot archive file
    path: PathBuf,

    /// Slot that the snapshot was made
    slot: Slot,

    /// Hash of the accounts at this slot
    hash: Hash,

    /// Archive format for the snapshot file
    archive_format: ArchiveFormat,
}

/// Information about a full snapshot archive: its path, slot, hash, and archive format
#[derive(PartialEq, Eq, Debug)]
pub struct FullSnapshotArchiveInfo(SnapshotArchiveInfo);

impl FullSnapshotArchiveInfo {
    /// Parse the path to a full snapshot archive and return a new `FullSnapshotArchiveInfo`
    fn new_from_path(path: PathBuf) -> Result<Self> {
        let filename = path_to_file_name_str(path.as_path())?;
        let (slot, hash, archive_format) = parse_full_snapshot_archive_filename(filename)?;

        Ok(Self(SnapshotArchiveInfo {
            path,
            slot,
            hash,
            archive_format,
        }))
    }

    pub fn path(&self) -> &PathBuf {
        &self.0.path
    }

    pub fn slot(&self) -> &Slot {
        &self.0.slot
    }

    pub fn hash(&self) -> &Hash {
        &self.0.hash
    }

    pub fn archive_format(&self) -> &ArchiveFormat {
        &self.0.archive_format
    }
}

impl PartialOrd for FullSnapshotArchiveInfo {
    fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
        Some(self.cmp(other))
    }
}

// Order `FullSnapshotArchiveInfo` by slot (ascending), which practially is sorting chronologically
impl Ord for FullSnapshotArchiveInfo {
    fn cmp(&self, other: &Self) -> Ordering {
        self.slot().cmp(other.slot())
    }
}

/// Information about an incremental snapshot archive: its path, slot, base slot, hash, and archive format
#[derive(PartialEq, Eq, Debug)]
pub struct IncrementalSnapshotArchiveInfo {
    /// The slot that the incremental snapshot was based from.  This is the same as the full
    /// snapshot slot used when making the incremental snapshot.
    base_slot: Slot,

    /// Use the `SnapshotArchiveInfo` struct for the common fields: path, slot, hash, and
    /// archive_format, but as they pertain to the incremental snapshot.
    inner: SnapshotArchiveInfo,
}

impl IncrementalSnapshotArchiveInfo {
    /// Parse the path to an incremental snapshot archive and return a new `IncrementalSnapshotArchiveInfo`
    fn new_from_path(path: PathBuf) -> Result<Self> {
        let filename = path_to_file_name_str(path.as_path())?;
        let (base_slot, slot, hash, archive_format) =
            parse_incremental_snapshot_archive_filename(filename)?;

        Ok(Self {
            base_slot,
            inner: SnapshotArchiveInfo {
                path,
                slot,
                hash,
                archive_format,
            },
        })
    }

    pub fn path(&self) -> &PathBuf {
        &self.inner.path
    }

    pub fn base_slot(&self) -> &Slot {
        &self.base_slot
    }

    pub fn slot(&self) -> &Slot {
        &self.inner.slot
    }

    fn _hash(&self) -> &Hash {
        &self.inner.hash
    }

    fn _archive_format(&self) -> &ArchiveFormat {
        &self.inner.archive_format
    }
}

impl PartialOrd for IncrementalSnapshotArchiveInfo {
    fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
        Some(self.cmp(other))
    }
}

// Order `IncrementalSnapshotArchiveInfo` by base slot (ascending), then slot (ascending), which
// practially is sorting chronologically
impl Ord for IncrementalSnapshotArchiveInfo {
    fn cmp(&self, other: &Self) -> Ordering {
        self.base_slot()
            .cmp(other.base_slot())
            .then(self.slot().cmp(other.slot()))
    }
}

pub const SNAPSHOT_STATUS_CACHE_FILE_NAME: &str = "status_cache";

pub const MAX_BANK_SNAPSHOTS: usize = 8; // Save some snapshots but not too many
const MAX_SNAPSHOT_DATA_FILE_SIZE: u64 = 32 * 1024 * 1024 * 1024; // 32 GiB
const VERSION_STRING_V1_2_0: &str = "1.2.0";
const DEFAULT_SNAPSHOT_VERSION: SnapshotVersion = SnapshotVersion::V1_2_0;
pub(crate) const TMP_FULL_SNAPSHOT_PREFIX: &str = "tmp-snapshot-";
pub(crate) const TMP_INCREMENTAL_SNAPSHOT_PREFIX: &str = "tmp-incremental-snapshot-";
pub const DEFAULT_MAX_FULL_SNAPSHOT_ARCHIVES_TO_RETAIN: usize = 2;
pub const FULL_SNAPSHOT_ARCHIVE_FILENAME_REGEX: &str = r"^snapshot-(?P<slot>[[:digit:]]+)-(?P<hash>[[:alnum:]]+)\.(?P<ext>tar|tar\.bz2|tar\.zst|tar\.gz)$";
pub const INCREMENTAL_SNAPSHOT_ARCHIVE_FILENAME_REGEX: &str = r"^incremental-snapshot-(?P<base>[[:digit:]]+)-(?P<slot>[[:digit:]]+)-(?P<hash>[[:alnum:]]+)\.(?P<ext>tar|tar\.bz2|tar\.zst|tar\.gz)$";

#[derive(Copy, Clone, Eq, PartialEq, Debug)]
pub enum SnapshotVersion {
    V1_2_0,
}

impl Default for SnapshotVersion {
    fn default() -> Self {
        DEFAULT_SNAPSHOT_VERSION
    }
}

impl fmt::Display for SnapshotVersion {
    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
        f.write_str(From::from(*self))
    }
}

impl From<SnapshotVersion> for &'static str {
    fn from(snapshot_version: SnapshotVersion) -> &'static str {
        match snapshot_version {
            SnapshotVersion::V1_2_0 => VERSION_STRING_V1_2_0,
        }
    }
}

impl FromStr for SnapshotVersion {
    type Err = &'static str;

    fn from_str(version_string: &str) -> std::result::Result<Self, Self::Err> {
        // Remove leading 'v' or 'V' from slice
        let version_string = if version_string
            .get(..1)
            .map_or(false, |s| s.eq_ignore_ascii_case("v"))
        {
            &version_string[1..]
        } else {
            version_string
        };
        match version_string {
            VERSION_STRING_V1_2_0 => Ok(SnapshotVersion::V1_2_0),
            _ => Err("unsupported snapshot version"),
        }
    }
}

impl SnapshotVersion {
    pub fn as_str(self) -> &'static str {
        <&str as From<Self>>::from(self)
    }

    fn maybe_from_string(version_string: &str) -> Option<SnapshotVersion> {
        version_string.parse::<Self>().ok()
    }
}

/// The different archive formats used for snapshots
#[derive(Copy, Clone, Debug, Eq, PartialEq)]
pub enum ArchiveFormat {
    TarBzip2,
    TarGzip,
    TarZstd,
    Tar,
}

/// A slot and the path to its bank snapshot
#[derive(PartialEq, Eq, Debug)]
pub struct BankSnapshotInfo {
    pub slot: Slot,
    pub snapshot_path: PathBuf,
}

impl PartialOrd for BankSnapshotInfo {
    fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
        Some(self.cmp(other))
    }
}

// Order BankSnapshotInfo by slot (ascending), which practially is sorting chronologically
impl Ord for BankSnapshotInfo {
    fn cmp(&self, other: &Self) -> Ordering {
        self.slot.cmp(&other.slot)
    }
}

/// Helper type when rebuilding from snapshots.  Designed to handle when rebuilding from just a
/// full snapshot, or from both a full snapshot and an incremental snapshot.
#[derive(Debug)]
struct SnapshotRootPaths {
    full_snapshot_root_file_path: PathBuf,
    incremental_snapshot_root_file_path: Option<PathBuf>,
}

/// Helper type to bundle up the results from `unarchive_snapshot()`
#[derive(Debug)]
struct UnarchivedSnapshot {
    unpack_dir: TempDir,
    unpacked_append_vec_map: UnpackedAppendVecMap,
    unpacked_snapshots_dir_and_version: UnpackedSnapshotsDirAndVersion,
    measure_untar: Measure,
}

/// Helper type for passing around the unpacked snapshots dir and the snapshot version together
#[derive(Debug)]
struct UnpackedSnapshotsDirAndVersion {
    unpacked_snapshots_dir: PathBuf,
    snapshot_version: String,
}

#[derive(Error, Debug)]
pub enum SnapshotError {
    #[error("I/O error: {0}")]
    Io(#[from] std::io::Error),

    #[error("serialization error: {0}")]
    Serialize(#[from] bincode::Error),

    #[error("archive generation failure {0}")]
    ArchiveGenerationFailure(ExitStatus),

    #[error("storage path symlink is invalid")]
    StoragePathSymlinkInvalid,

    #[error("Unpack error: {0}")]
    UnpackError(#[from] UnpackError),

    #[error("accounts package send error")]
    AccountsPackageSendError(#[from] AccountsPackageSendError),

    #[error("source({1}) - I/O error: {0}")]
    IoWithSource(std::io::Error, &'static str),

    #[error("could not get file name from path: {}", .0.display())]
    PathToFileNameError(PathBuf),

    #[error("could not get str from file name: {}", .0.display())]
    FileNameToStrError(PathBuf),

    #[error("could not parse snapshot archive's file name: {0}")]
    ParseSnapshotArchiveFileNameError(String),

    #[error("snapshots are incompatible: full snapshot slot ({0}) and incremental snapshot base slot ({1}) do not match")]
    MismatchedBaseSlot(Slot, Slot),
}
pub type Result<T> = std::result::Result<T, SnapshotError>;

fn get_archive_ext(archive_format: ArchiveFormat) -> &'static str {
    match archive_format {
        ArchiveFormat::TarBzip2 => "tar.bz2",
        ArchiveFormat::TarGzip => "tar.gz",
        ArchiveFormat::TarZstd => "tar.zst",
        ArchiveFormat::Tar => "tar",
    }
}

/// If the validator halts in the middle of `archive_snapshot_package()`, the temporary staging
/// directory won't be cleaned up.  Call this function to clean them up.
pub fn remove_tmp_snapshot_archives(snapshot_archives_dir: &Path) {
    if let Ok(entries) = fs::read_dir(snapshot_archives_dir) {
        for entry in entries.filter_map(|entry| entry.ok()) {
            let file_name = entry
                .file_name()
                .into_string()
                .unwrap_or_else(|_| String::new());
            if file_name.starts_with(TMP_FULL_SNAPSHOT_PREFIX)
                || file_name.starts_with(TMP_INCREMENTAL_SNAPSHOT_PREFIX)
            {
                if entry.path().is_file() {
                    fs::remove_file(entry.path())
                } else {
                    fs::remove_dir_all(entry.path())
                }
                .unwrap_or_else(|err| {
                    warn!("Failed to remove {}: {}", entry.path().display(), err)
                });
            }
        }
    }
}

/// Make a full snapshot archive out of the AccountsPackage
pub fn archive_snapshot_package(
    snapshot_package: &AccountsPackage,
    maximum_snapshots_to_retain: usize,
) -> Result<()> {
    info!(
        "Generating snapshot archive for slot {}",
        snapshot_package.slot
    );

    serialize_status_cache(
        snapshot_package.slot,
        &snapshot_package.slot_deltas,
        &snapshot_package
            .snapshot_links
            .path()
            .join(SNAPSHOT_STATUS_CACHE_FILE_NAME),
    )?;

    let mut timer = Measure::start("snapshot_package-package_snapshots");
    let tar_dir = snapshot_package
        .tar_output_file
        .parent()
        .expect("Tar output path is invalid");

    fs::create_dir_all(tar_dir)
        .map_err(|e| SnapshotError::IoWithSource(e, "create archive path"))?;

    // Create the staging directories
    let staging_dir = tempfile::Builder::new()
        .prefix(&format!(
            "{}{}-",
            TMP_FULL_SNAPSHOT_PREFIX, snapshot_package.slot
        ))
        .tempdir_in(tar_dir)
        .map_err(|e| SnapshotError::IoWithSource(e, "create archive tempdir"))?;

    let staging_accounts_dir = staging_dir.path().join("accounts");
    let staging_snapshots_dir = staging_dir.path().join("snapshots");
    let staging_version_file = staging_dir.path().join("version");
    fs::create_dir_all(&staging_accounts_dir)
        .map_err(|e| SnapshotError::IoWithSource(e, "create staging path"))?;

    // Add the snapshots to the staging directory
    symlink::symlink_dir(
        snapshot_package.snapshot_links.path(),
        &staging_snapshots_dir,
    )
    .map_err(|e| SnapshotError::IoWithSource(e, "create staging symlinks"))?;

    // Add the AppendVecs into the compressible list
    for storage in snapshot_package.storages.iter().flatten() {
        storage.flush()?;
        let storage_path = storage.get_path();
        let output_path = staging_accounts_dir.join(crate::append_vec::AppendVec::file_name(
            storage.slot(),
            storage.append_vec_id(),
        ));

        // `storage_path` - The file path where the AppendVec itself is located
        // `output_path` - The file path where the AppendVec will be placed in the staging directory.
        let storage_path =
            fs::canonicalize(storage_path).expect("Could not get absolute path for accounts");
        symlink::symlink_file(storage_path, &output_path)
            .map_err(|e| SnapshotError::IoWithSource(e, "create storage symlink"))?;
        if !output_path.is_file() {
            return Err(SnapshotError::StoragePathSymlinkInvalid);
        }
    }

    // Write version file
    {
        let mut f = fs::File::create(staging_version_file)
            .map_err(|e| SnapshotError::IoWithSource(e, "create version file"))?;
        f.write_all(snapshot_package.snapshot_version.as_str().as_bytes())
            .map_err(|e| SnapshotError::IoWithSource(e, "write version file"))?;
    }

    let file_ext = get_archive_ext(snapshot_package.archive_format);

    // Tar the staging directory into the archive at `archive_path`
    //
    // system `tar` program is used for -S (sparse file support)
    let archive_path = tar_dir.join(format!(
        "{}{}.{}",
        TMP_FULL_SNAPSHOT_PREFIX, snapshot_package.slot, file_ext
    ));

    let mut tar = process::Command::new("tar")
        .args(&[
            "chS",
            "-C",
            staging_dir.path().to_str().unwrap(),
            "accounts",
            "snapshots",
            "version",
        ])
        .stdin(process::Stdio::null())
        .stdout(process::Stdio::piped())
        .stderr(process::Stdio::inherit())
        .spawn()
        .map_err(|e| SnapshotError::IoWithSource(e, "tar process spawn"))?;

    match &mut tar.stdout {
        None => {
            return Err(SnapshotError::Io(IoError::new(
                ErrorKind::Other,
                "tar stdout unavailable".to_string(),
            )));
        }
        Some(tar_output) => {
            let mut archive_file = fs::File::create(&archive_path)?;

            match snapshot_package.archive_format {
                ArchiveFormat::TarBzip2 => {
                    let mut encoder =
                        bzip2::write::BzEncoder::new(archive_file, bzip2::Compression::best());
                    io::copy(tar_output, &mut encoder)?;
                    let _ = encoder.finish()?;
                }
                ArchiveFormat::TarGzip => {
                    let mut encoder =
                        flate2::write::GzEncoder::new(archive_file, flate2::Compression::default());
                    io::copy(tar_output, &mut encoder)?;
                    let _ = encoder.finish()?;
                }
                ArchiveFormat::Tar => {
                    io::copy(tar_output, &mut archive_file)?;
                }
                ArchiveFormat::TarZstd => {
                    let mut encoder = zstd::stream::Encoder::new(archive_file, 0)?;
                    io::copy(tar_output, &mut encoder)?;
                    let _ = encoder.finish()?;
                }
            };
        }
    }

    let tar_exit_status = tar
        .wait()
        .map_err(|e| SnapshotError::IoWithSource(e, "tar process wait"))?;
    if !tar_exit_status.success() {
        warn!("tar command failed with exit code: {}", tar_exit_status);
        return Err(SnapshotError::ArchiveGenerationFailure(tar_exit_status));
    }

    // Atomically move the archive into position for other validators to find
    let metadata = fs::metadata(&archive_path)
        .map_err(|e| SnapshotError::IoWithSource(e, "archive path stat"))?;
    fs::rename(&archive_path, &snapshot_package.tar_output_file)
        .map_err(|e| SnapshotError::IoWithSource(e, "archive path rename"))?;

    purge_old_snapshot_archives(tar_dir, maximum_snapshots_to_retain);

    timer.stop();
    info!(
        "Successfully created {:?}. slot: {}, elapsed ms: {}, size={}",
        snapshot_package.tar_output_file,
        snapshot_package.slot,
        timer.as_ms(),
        metadata.len()
    );
    datapoint_info!(
        "snapshot-package",
        ("slot", snapshot_package.slot, i64),
        ("duration_ms", timer.as_ms(), i64),
        ("size", metadata.len(), i64)
    );
    Ok(())
}

/// Get a list of bank snapshots in a directory
pub fn get_bank_snapshots<P>(snapshots_dir: P) -> Vec<BankSnapshotInfo>
where
    P: AsRef<Path>,
{
    match fs::read_dir(&snapshots_dir) {
        Ok(paths) => paths
            .filter_map(|entry| {
                entry.ok().and_then(|e| {
                    e.path()
                        .file_name()
                        .and_then(|n| n.to_str().map(|s| s.parse::<Slot>().ok()))
                        .unwrap_or(None)
                })
            })
            .map(|slot| {
                let snapshot_file_name = get_snapshot_file_name(slot);
                // So nice I join-ed it twice!  The redundant `snapshot_file_name` is unintentional
                // and should be simplified.  Kept for compatibility.
                let snapshot_path = snapshots_dir
                    .as_ref()
                    .join(&snapshot_file_name)
                    .join(snapshot_file_name);
                BankSnapshotInfo {
                    slot,
                    snapshot_path,
                }
            })
            .collect::<Vec<BankSnapshotInfo>>(),
        Err(err) => {
            info!(
                "Unable to read snapshots directory {}: {}",
                snapshots_dir.as_ref().display(),
                err
            );
            vec![]
        }
    }
}

/// Get the bank snapshot with the highest slot in a directory
pub fn get_highest_bank_snapshot_info<P>(snapshots_dir: P) -> Option<BankSnapshotInfo>
where
    P: AsRef<Path>,
{
    let mut bank_snapshot_infos = get_bank_snapshots(snapshots_dir);
    bank_snapshot_infos.sort_unstable();
    bank_snapshot_infos.into_iter().rev().next()
}

pub fn serialize_snapshot_data_file<F>(data_file_path: &Path, serializer: F) -> Result<u64>
where
    F: FnOnce(&mut BufWriter<File>) -> Result<()>,
{
    serialize_snapshot_data_file_capped::<F>(
        data_file_path,
        MAX_SNAPSHOT_DATA_FILE_SIZE,
        serializer,
    )
}

pub fn deserialize_snapshot_data_file<T: Sized>(
    data_file_path: &Path,
    deserializer: impl FnOnce(&mut BufReader<File>) -> Result<T>,
) -> Result<T> {
    let wrapped_deserializer = move |streams: &mut SnapshotStreams<File>| -> Result<T> {
        deserializer(&mut streams.full_snapshot_stream)
    };

    let wrapped_data_file_path = SnapshotRootPaths {
        full_snapshot_root_file_path: data_file_path.to_path_buf(),
        incremental_snapshot_root_file_path: None,
    };

    deserialize_snapshot_data_files_capped(
        &wrapped_data_file_path,
        MAX_SNAPSHOT_DATA_FILE_SIZE,
        wrapped_deserializer,
    )
}

fn deserialize_snapshot_data_files<T: Sized>(
    snapshot_root_paths: &SnapshotRootPaths,
    deserializer: impl FnOnce(&mut SnapshotStreams<File>) -> Result<T>,
) -> Result<T> {
    deserialize_snapshot_data_files_capped(
        snapshot_root_paths,
        MAX_SNAPSHOT_DATA_FILE_SIZE,
        deserializer,
    )
}

fn serialize_snapshot_data_file_capped<F>(
    data_file_path: &Path,
    maximum_file_size: u64,
    serializer: F,
) -> Result<u64>
where
    F: FnOnce(&mut BufWriter<File>) -> Result<()>,
{
    let data_file = File::create(data_file_path)?;
    let mut data_file_stream = BufWriter::new(data_file);
    serializer(&mut data_file_stream)?;
    data_file_stream.flush()?;

    let consumed_size = data_file_stream.stream_position()?;
    if consumed_size > maximum_file_size {
        let error_message = format!(
            "too large snapshot data file to serialize: {:?} has {} bytes",
            data_file_path, consumed_size
        );
        return Err(get_io_error(&error_message));
    }
    Ok(consumed_size)
}

fn deserialize_snapshot_data_files_capped<T: Sized>(
    snapshot_root_paths: &SnapshotRootPaths,
    maximum_file_size: u64,
    deserializer: impl FnOnce(&mut SnapshotStreams<File>) -> Result<T>,
) -> Result<T> {
    let (full_snapshot_file_size, mut full_snapshot_data_file_stream) =
        create_snapshot_data_file_stream(
            &snapshot_root_paths.full_snapshot_root_file_path,
            maximum_file_size,
        )?;

    let (incremental_snapshot_file_size, mut incremental_snapshot_data_file_stream) =
        if let Some(ref incremental_snapshot_root_file_path) =
            snapshot_root_paths.incremental_snapshot_root_file_path
        {
            let (incremental_snapshot_file_size, incremental_snapshot_data_file_stream) =
                create_snapshot_data_file_stream(
                    incremental_snapshot_root_file_path,
                    maximum_file_size,
                )?;
            (
                Some(incremental_snapshot_file_size),
                Some(incremental_snapshot_data_file_stream),
            )
        } else {
            (None, None)
        };

    let mut snapshot_streams = SnapshotStreams {
        full_snapshot_stream: &mut full_snapshot_data_file_stream,
        incremental_snapshot_stream: incremental_snapshot_data_file_stream.as_mut(),
    };
    let ret = deserializer(&mut snapshot_streams)?;

    check_deserialize_file_consumed(
        full_snapshot_file_size,
        &snapshot_root_paths.full_snapshot_root_file_path,
        &mut full_snapshot_data_file_stream,
    )?;

    if let Some(ref incremental_snapshot_root_file_path) =
        snapshot_root_paths.incremental_snapshot_root_file_path
    {
        check_deserialize_file_consumed(
            incremental_snapshot_file_size.unwrap(),
            incremental_snapshot_root_file_path,
            incremental_snapshot_data_file_stream.as_mut().unwrap(),
        )?;
    }

    Ok(ret)
}

/// Before running the deserializer function, perform common operations on the snapshot archive
/// files, such as checking the file size and opening the file into a stream.
fn create_snapshot_data_file_stream<P>(
    snapshot_root_file_path: P,
    maximum_file_size: u64,
) -> Result<(u64, BufReader<File>)>
where
    P: AsRef<Path>,
{
    let snapshot_file_size = fs::metadata(&snapshot_root_file_path)?.len();

    if snapshot_file_size > maximum_file_size {
        let error_message =
            format!(
            "too large snapshot data file to deserialize: {} has {} bytes (max size is {} bytes)",
            snapshot_root_file_path.as_ref().display(), snapshot_file_size, maximum_file_size
        );
        return Err(get_io_error(&error_message));
    }

    let snapshot_data_file = File::open(&snapshot_root_file_path)?;
    let snapshot_data_file_stream = BufReader::new(snapshot_data_file);

    Ok((snapshot_file_size, snapshot_data_file_stream))
}

/// After running the deserializer function, perform common checks to ensure the snapshot archive
/// files were consumed correctly.
fn check_deserialize_file_consumed<P>(
    file_size: u64,
    file_path: P,
    file_stream: &mut BufReader<File>,
) -> Result<()>
where
    P: AsRef<Path>,
{
    let consumed_size = file_stream.stream_position()?;

    if consumed_size != file_size {
        let error_message =
            format!(
            "invalid snapshot data file: {} has {} bytes, however consumed {} bytes to deserialize",
            file_path.as_ref().display(), file_size, consumed_size
        );
        return Err(get_io_error(&error_message));
    }

    Ok(())
}

/// Serialize a bank to a snapshot
pub fn add_bank_snapshot<P: AsRef<Path>>(
    snapshots_dir: P,
    bank: &Bank,
    snapshot_storages: &[SnapshotStorage],
    snapshot_version: SnapshotVersion,
) -> Result<BankSnapshotInfo> {
    let slot = bank.slot();
    // snapshots_dir/slot
    let bank_snapshots_dir = get_bank_snapshots_dir(snapshots_dir, slot);
    fs::create_dir_all(&bank_snapshots_dir)?;

    // the bank snapshot is stored as snapshots_dir/slot/slot
    let snapshot_bank_file_path = bank_snapshots_dir.join(get_snapshot_file_name(slot));
    info!(
        "Creating snapshot for slot {}, path: {:?}",
        slot, snapshot_bank_file_path,
    );

    let mut bank_serialize = Measure::start("bank-serialize-ms");
    let bank_snapshot_serializer = move |stream: &mut BufWriter<File>| -> Result<()> {
        let serde_style = match snapshot_version {
            SnapshotVersion::V1_2_0 => SerdeStyle::Newer,
        };
        bank_to_stream(serde_style, stream.by_ref(), bank, snapshot_storages)?;
        Ok(())
    };
    let consumed_size =
        serialize_snapshot_data_file(&snapshot_bank_file_path, bank_snapshot_serializer)?;
    bank_serialize.stop();

    // Monitor sizes because they're capped to MAX_SNAPSHOT_DATA_FILE_SIZE
    datapoint_info!(
        "snapshot-bank-file",
        ("slot", slot, i64),
        ("size", consumed_size, i64)
    );

    inc_new_counter_info!("bank-serialize-ms", bank_serialize.as_ms() as usize);

    info!(
        "{} for slot {} at {:?}",
        bank_serialize, slot, snapshot_bank_file_path,
    );

    Ok(BankSnapshotInfo {
        slot,
        snapshot_path: snapshot_bank_file_path,
    })
}

fn serialize_status_cache(
    slot: Slot,
    slot_deltas: &[BankSlotDelta],
    status_cache_path: &Path,
) -> Result<()> {
    let mut status_cache_serialize = Measure::start("status_cache_serialize-ms");
    let consumed_size = serialize_snapshot_data_file(status_cache_path, |stream| {
        serialize_into(stream, slot_deltas)?;
        Ok(())
    })?;
    status_cache_serialize.stop();

    // Monitor sizes because they're capped to MAX_SNAPSHOT_DATA_FILE_SIZE
    datapoint_info!(
        "snapshot-status-cache-file",
        ("slot", slot, i64),
        ("size", consumed_size, i64)
    );

    inc_new_counter_info!(
        "serialize-status-cache-ms",
        status_cache_serialize.as_ms() as usize
    );
    Ok(())
}

/// Remove the snapshot directory for this slot
pub fn remove_bank_snapshot<P>(slot: Slot, snapshots_dir: P) -> Result<()>
where
    P: AsRef<Path>,
{
    let bank_snapshot_dir = get_bank_snapshots_dir(&snapshots_dir, slot);
    fs::remove_dir_all(bank_snapshot_dir)?;
    Ok(())
}

#[derive(Debug, Default)]
pub struct BankFromArchiveTimings {
    pub rebuild_bank_from_snapshots_us: u64,
    pub full_snapshot_untar_us: u64,
    pub incremental_snapshot_untar_us: u64,
    pub verify_snapshot_bank_us: u64,
}

// From testing, 4 seems to be a sweet spot for ranges of 60M-360M accounts and 16-64 cores. This may need to be tuned later.
const PARALLEL_UNTAR_READERS_DEFAULT: usize = 4;

/// Rebuild bank from snapshot archives.  Handles either just a full snapshot, or both a full
/// snapshot and an incremental snapshot.
#[allow(clippy::too_many_arguments)]
pub fn bank_from_snapshot_archives<P>(
    account_paths: &[PathBuf],
    frozen_account_pubkeys: &[Pubkey],
    snapshots_dir: &Path,
    full_snapshot_archive_path: P,
    incremental_snapshot_archive_path: Option<P>,
    archive_format: ArchiveFormat,
    genesis_config: &GenesisConfig,
    debug_keys: Option<Arc<HashSet<Pubkey>>>,
    additional_builtins: Option<&Builtins>,
    account_secondary_indexes: AccountSecondaryIndexes,
    accounts_db_caching_enabled: bool,
    limit_load_slot_count_from_snapshot: Option<usize>,
    shrink_ratio: AccountShrinkThreshold,
    test_hash_calculation: bool,
    verify_index: bool,
) -> Result<(Bank, BankFromArchiveTimings)>
where
    P: AsRef<Path> + std::marker::Sync,
{
    let parallel_divisions = std::cmp::min(
        PARALLEL_UNTAR_READERS_DEFAULT,
        std::cmp::max(1, num_cpus::get() / 4),
    );

    let unarchived_full_snapshot = unarchive_snapshot(
        snapshots_dir,
        TMP_FULL_SNAPSHOT_PREFIX,
        &full_snapshot_archive_path,
        "snapshot untar",
        account_paths,
        archive_format,
        parallel_divisions,
    )?;

    let mut unarchived_incremental_snapshot =
        if let Some(incremental_snapshot_archive_path) = incremental_snapshot_archive_path {
            check_are_snapshots_compatible(
                &full_snapshot_archive_path,
                &incremental_snapshot_archive_path,
            )?;

            let unarchived_incremental_snapshot = unarchive_snapshot(
                snapshots_dir,
                TMP_INCREMENTAL_SNAPSHOT_PREFIX,
                &incremental_snapshot_archive_path,
                "incremental snapshot untar",
                account_paths,
                archive_format,
                parallel_divisions,
            )?;
            Some(unarchived_incremental_snapshot)
        } else {
            None
        };

    let mut unpacked_append_vec_map = unarchived_full_snapshot.unpacked_append_vec_map;
    if let Some(ref mut unarchive_preparation_result) = unarchived_incremental_snapshot {
        let incremental_snapshot_unpacked_append_vec_map =
            std::mem::take(&mut unarchive_preparation_result.unpacked_append_vec_map);
        unpacked_append_vec_map.extend(incremental_snapshot_unpacked_append_vec_map.into_iter());
    }

    let mut measure_rebuild = Measure::start("rebuild bank from snapshots");
    let bank = rebuild_bank_from_snapshots(
        &unarchived_full_snapshot.unpacked_snapshots_dir_and_version,
        unarchived_incremental_snapshot
            .as_ref()
            .map(|unarchive_preparation_result| {
                &unarchive_preparation_result.unpacked_snapshots_dir_and_version
            }),
        frozen_account_pubkeys,
        account_paths,
        unpacked_append_vec_map,
        genesis_config,
        debug_keys,
        additional_builtins,
        account_secondary_indexes,
        accounts_db_caching_enabled,
        limit_load_slot_count_from_snapshot,
        shrink_ratio,
        verify_index,
    )?;
    measure_rebuild.stop();
    info!("{}", measure_rebuild);

    let mut measure_verify = Measure::start("verify");
    if !bank.verify_snapshot_bank(test_hash_calculation)
        && limit_load_slot_count_from_snapshot.is_none()
    {
        panic!("Snapshot bank for slot {} failed to verify", bank.slot());
    }
    measure_verify.stop();

    let timings = BankFromArchiveTimings {
        rebuild_bank_from_snapshots_us: measure_rebuild.as_us(),
        full_snapshot_untar_us: unarchived_full_snapshot.measure_untar.as_us(),
        incremental_snapshot_untar_us: unarchived_incremental_snapshot
            .map_or(0, |unarchive_preparation_result| {
                unarchive_preparation_result.measure_untar.as_us()
            }),
        verify_snapshot_bank_us: measure_verify.as_us(),
    };
    Ok((bank, timings))
}

/// Perform the common tasks when unarchiving a snapshot.  Handles creating the temporary
/// directories, untaring, reading the version file, and then returning those fields plus the
/// unpacked append vec map.
fn unarchive_snapshot<P, Q>(
    snapshots_dir: P,
    unpacked_snapshots_dir_prefix: &'static str,
    snapshot_archive_path: Q,
    measure_name: &'static str,
    account_paths: &[PathBuf],
    archive_format: ArchiveFormat,
    parallel_divisions: usize,
) -> Result<UnarchivedSnapshot>
where
    P: AsRef<Path>,
    Q: AsRef<Path>,
{
    let unpack_dir = tempfile::Builder::new()
        .prefix(unpacked_snapshots_dir_prefix)
        .tempdir_in(snapshots_dir)?;
    let unpacked_snapshots_dir = unpack_dir.path().join("snapshots");

    let mut measure_untar = Measure::start(measure_name);
    let unpacked_append_vec_map = untar_snapshot_in(
        snapshot_archive_path,
        unpack_dir.path(),
        account_paths,
        archive_format,
        parallel_divisions,
    )?;
    measure_untar.stop();
    info!("{}", measure_untar);

    let unpacked_version_file = unpack_dir.path().join("version");
    let snapshot_version = {
        let mut snapshot_version = String::new();
        File::open(unpacked_version_file)
            .and_then(|mut f| f.read_to_string(&mut snapshot_version))?;
        snapshot_version.trim().to_string()
    };

    Ok(UnarchivedSnapshot {
        unpack_dir,
        unpacked_append_vec_map,
        unpacked_snapshots_dir_and_version: UnpackedSnapshotsDirAndVersion {
            unpacked_snapshots_dir,
            snapshot_version,
        },
        measure_untar,
    })
}

/// Check if an incremental snapshot is compatible with a full snapshot.  This function parses the
/// paths to see if the incremental snapshot's base slot is the same as the full snapshot's slot.
/// Return an error if they are incompatible (or if the paths cannot be parsed), otherwise return a
/// tuple of the full snapshot slot and the incremental snapshot slot.
fn check_are_snapshots_compatible<P>(
    full_snapshot_archive_path: P,
    incremental_snapshot_archive_path: P,
) -> Result<()>
where
    P: AsRef<Path>,
{
    let full_snapshot_filename = path_to_file_name_str(full_snapshot_archive_path.as_ref())?;
    let (full_snapshot_slot, _, _) = parse_full_snapshot_archive_filename(full_snapshot_filename)?;

    let incremental_snapshot_filename =
        path_to_file_name_str(incremental_snapshot_archive_path.as_ref())?;
    let (incremental_snapshot_base_slot, _, _, _) =
        parse_incremental_snapshot_archive_filename(incremental_snapshot_filename)?;

    (full_snapshot_slot == incremental_snapshot_base_slot)
        .then(|| ())
        .ok_or(SnapshotError::MismatchedBaseSlot(
            full_snapshot_slot,
            incremental_snapshot_base_slot,
        ))
}

/// Get the `&str` from a `&Path`
fn path_to_file_name_str(path: &Path) -> Result<&str> {
    path.file_name()
        .ok_or_else(|| SnapshotError::PathToFileNameError(path.to_path_buf()))?
        .to_str()
        .ok_or_else(|| SnapshotError::FileNameToStrError(path.to_path_buf()))
}

/// Build the full snapshot archive path from its components: the snapshot archives directory, the
/// snapshot slot, the accounts hash, and the archive format.
pub fn build_full_snapshot_archive_path(
    snapshot_archives_dir: PathBuf,
    slot: Slot,
    hash: &Hash,
    archive_format: ArchiveFormat,
) -> PathBuf {
    snapshot_archives_dir.join(format!(
        "snapshot-{}-{}.{}",
        slot,
        hash,
        get_archive_ext(archive_format),
    ))
}

/// Build the incremental snapshot archive path from its components: the snapshot archives
/// directory, the snapshot base slot, the snapshot slot, the accounts hash, and the archive
/// format.
pub fn build_incremental_snapshot_archive_path(
    snapshot_archives_dir: PathBuf,
    base_slot: Slot,
    slot: Slot,
    hash: &Hash,
    archive_format: ArchiveFormat,
) -> PathBuf {
    snapshot_archives_dir.join(format!(
        "incremental-snapshot-{}-{}-{}.{}",
        base_slot,
        slot,
        hash,
        get_archive_ext(archive_format),
    ))
}

fn archive_format_from_str(archive_format: &str) -> Option<ArchiveFormat> {
    match archive_format {
        "tar.bz2" => Some(ArchiveFormat::TarBzip2),
        "tar.gz" => Some(ArchiveFormat::TarGzip),
        "tar.zst" => Some(ArchiveFormat::TarZstd),
        "tar" => Some(ArchiveFormat::Tar),
        _ => None,
    }
}

/// Parse a full snapshot archive filename into its Slot, Hash, and Archive Format
fn parse_full_snapshot_archive_filename(
    archive_filename: &str,
) -> Result<(Slot, Hash, ArchiveFormat)> {
    lazy_static! {
        static ref RE: Regex = Regex::new(FULL_SNAPSHOT_ARCHIVE_FILENAME_REGEX).unwrap();
    }

    let do_parse = || {
        RE.captures(archive_filename).and_then(|captures| {
            let slot = captures
                .name("slot")
                .map(|x| x.as_str().parse::<Slot>())?
                .ok()?;
            let hash = captures
                .name("hash")
                .map(|x| x.as_str().parse::<Hash>())?
                .ok()?;
            let archive_format = captures
                .name("ext")
                .map(|x| archive_format_from_str(x.as_str()))??;

            Some((slot, hash, archive_format))
        })
    };

    do_parse().ok_or_else(|| {
        SnapshotError::ParseSnapshotArchiveFileNameError(archive_filename.to_string())
    })
}

/// Parse an incremental snapshot archive filename into its base Slot, actual Slot, Hash, and Archive Format
fn parse_incremental_snapshot_archive_filename(
    archive_filename: &str,
) -> Result<(Slot, Slot, Hash, ArchiveFormat)> {
    lazy_static! {
        static ref RE: Regex = Regex::new(INCREMENTAL_SNAPSHOT_ARCHIVE_FILENAME_REGEX).unwrap();
    }

    let do_parse = || {
        RE.captures(archive_filename).and_then(|captures| {
            let base_slot = captures
                .name("base")
                .map(|x| x.as_str().parse::<Slot>())?
                .ok()?;
            let slot = captures
                .name("slot")
                .map(|x| x.as_str().parse::<Slot>())?
                .ok()?;
            let hash = captures
                .name("hash")
                .map(|x| x.as_str().parse::<Hash>())?
                .ok()?;
            let archive_format = captures
                .name("ext")
                .map(|x| archive_format_from_str(x.as_str()))??;

            Some((base_slot, slot, hash, archive_format))
        })
    };

    do_parse().ok_or_else(|| {
        SnapshotError::ParseSnapshotArchiveFileNameError(archive_filename.to_string())
    })
}

/// Get a list of the full snapshot archives in a directory
pub fn get_full_snapshot_archives<P>(snapshot_archives_dir: P) -> Vec<FullSnapshotArchiveInfo>
where
    P: AsRef<Path>,
{
    match fs::read_dir(&snapshot_archives_dir) {
        Err(err) => {
            info!(
                "Unable to read snapshot archives directory: err: {}, path: {}",
                err,
                snapshot_archives_dir.as_ref().display()
            );
            vec![]
        }
        Ok(files) => files
            .filter_map(|entry| {
                entry.map_or(None, |entry| {
                    FullSnapshotArchiveInfo::new_from_path(entry.path()).ok()
                })
            })
            .collect(),
    }
}

/// Get a list of the incremental snapshot archives in a directory
fn get_incremental_snapshot_archives<P>(
    snapshot_archives_dir: P,
) -> Vec<IncrementalSnapshotArchiveInfo>
where
    P: AsRef<Path>,
{
    match fs::read_dir(&snapshot_archives_dir) {
        Err(err) => {
            info!(
                "Unable to read snapshot archives directory: err: {}, path: {}",
                err,
                snapshot_archives_dir.as_ref().display()
            );
            vec![]
        }
        Ok(files) => files
            .filter_map(|entry| {
                entry.map_or(None, |entry| {
                    IncrementalSnapshotArchiveInfo::new_from_path(entry.path()).ok()
                })
            })
            .collect(),
    }
}

/// Get the highest slot of the full snapshot archives in a directory
pub fn get_highest_full_snapshot_archive_slot<P>(snapshot_archives_dir: P) -> Option<Slot>
where
    P: AsRef<Path>,
{
    get_highest_full_snapshot_archive_info(snapshot_archives_dir)
        .map(|full_snapshot_archive_info| *full_snapshot_archive_info.slot())
}

/// Get the highest slot of the incremental snapshot archives in a directory, for a given full
/// snapshot slot
pub fn get_highest_incremental_snapshot_archive_slot<P: AsRef<Path>>(
    snapshot_archives_dir: P,
    full_snapshot_slot: Slot,
) -> Option<Slot> {
    get_highest_incremental_snapshot_archive_info(snapshot_archives_dir, full_snapshot_slot)
        .map(|incremental_snapshot_archive_info| *incremental_snapshot_archive_info.slot())
}

/// Get the path (and metadata) for the full snapshot archive with the highest slot in a directory
pub fn get_highest_full_snapshot_archive_info<P>(
    snapshot_archives_dir: P,
) -> Option<FullSnapshotArchiveInfo>
where
    P: AsRef<Path>,
{
    let mut full_snapshot_archives = get_full_snapshot_archives(snapshot_archives_dir);
    full_snapshot_archives.sort_unstable();
    full_snapshot_archives.into_iter().rev().next()
}

/// Get the path for the incremental snapshot archive with the highest slot, for a given full
/// snapshot slot, in a directory
pub fn get_highest_incremental_snapshot_archive_info<P>(
    snapshot_archives_dir: P,
    full_snapshot_slot: Slot,
) -> Option<IncrementalSnapshotArchiveInfo>
where
    P: AsRef<Path>,
{
    // Since we want to filter down to only the incremental snapshot archives that have the same
    // full snapshot slot as the value passed in, perform the filtering before sorting to avoid
    // doing unnecessary work.
    let mut incremental_snapshot_archives =
        get_incremental_snapshot_archives(snapshot_archives_dir)
            .into_iter()
            .filter(|incremental_snapshot_archive_info| {
                *incremental_snapshot_archive_info.base_slot() == full_snapshot_slot
            })
            .collect::<Vec<_>>();
    incremental_snapshot_archives.sort_unstable();
    incremental_snapshot_archives.into_iter().rev().next()
}

pub fn purge_old_snapshot_archives<P>(snapshot_archives_dir: P, maximum_snapshots_to_retain: usize)
where
    P: AsRef<Path>,
{
    info!(
        "Purging old snapshot archives in {}, retaining {} full snapshots",
        snapshot_archives_dir.as_ref().display(),
        maximum_snapshots_to_retain
    );
    let mut snapshot_archives = get_full_snapshot_archives(&snapshot_archives_dir);
    snapshot_archives.sort_unstable();
    // Keep the oldest snapshot so we can always play the ledger from it.
    snapshot_archives.pop();
    let max_snaps = max(1, maximum_snapshots_to_retain);
    for old_archive in snapshot_archives.into_iter().skip(max_snaps) {
        trace!(
            "Purging old full snapshot archive: {}",
            old_archive.path().display()
        );
        fs::remove_file(old_archive.path())
            .unwrap_or_else(|err| info!("Failed to remove old full snapshot archive: {}", err));
    }

    // Only keep incremental snapshots for the latest full snapshot
    // bprumo TODO issue #18639: As an option to further reduce the number of incremental
    // snapshots, only a subset of the incremental snapshots for the lastest full snapshot could be
    // kept.  This could reuse maximum_snapshots_to_retain, or use a new field just for incremental
    // snapshots.
    // In case there are incremental snapshots but no full snapshots, make sure all the incremental
    // snapshots are purged.
    let last_full_snapshot_slot =
        get_highest_full_snapshot_archive_slot(&snapshot_archives_dir).unwrap_or(Slot::MAX);
    get_incremental_snapshot_archives(&snapshot_archives_dir)
        .iter()
        .filter(|archive_info| *archive_info.base_slot() < last_full_snapshot_slot)
        .for_each(|old_archive| {
            trace!(
                "Purging old incremental snapshot archive: {}",
                old_archive.path().display()
            );
            fs::remove_file(old_archive.path()).unwrap_or_else(|err| {
                info!("Failed to remove old incremental snapshot archive: {}", err)
            })
        });
}

fn unpack_snapshot_local<T: 'static + Read + std::marker::Send, F: Fn() -> T>(
    reader: F,
    ledger_dir: &Path,
    account_paths: &[PathBuf],
    parallel_archivers: usize,
) -> Result<UnpackedAppendVecMap> {
    assert!(parallel_archivers > 0);
    // a shared 'reader' that reads the decompressed stream once, keeps some history, and acts as a reader for multiple parallel archive readers
    let shared_buffer = SharedBuffer::new(reader());

    // allocate all readers before any readers start reading
    let readers = (0..parallel_archivers)
        .into_iter()
        .map(|_| SharedBufferReader::new(&shared_buffer))
        .collect::<Vec<_>>();

    // create 'parallel_archivers' # of parallel workers, each responsible for 1/parallel_archivers of all the files to extract.
    let all_unpacked_append_vec_map = readers
        .into_par_iter()
        .enumerate()
        .map(|(index, reader)| {
            let parallel_selector = Some(ParallelSelector {
                index,
                divisions: parallel_archivers,
            });
            let mut archive = Archive::new(reader);
            unpack_snapshot(&mut archive, ledger_dir, account_paths, parallel_selector)
        })
        .collect::<Vec<_>>();
    let mut unpacked_append_vec_map = UnpackedAppendVecMap::new();
    for h in all_unpacked_append_vec_map {
        unpacked_append_vec_map.extend(h?);
    }

    Ok(unpacked_append_vec_map)
}

fn untar_snapshot_in<P: AsRef<Path>>(
    snapshot_tar: P,
    unpack_dir: &Path,
    account_paths: &[PathBuf],
    archive_format: ArchiveFormat,
    parallel_divisions: usize,
) -> Result<UnpackedAppendVecMap> {
    let open_file = || File::open(&snapshot_tar).unwrap();
    let account_paths_map = match archive_format {
        ArchiveFormat::TarBzip2 => unpack_snapshot_local(
            || BzDecoder::new(BufReader::new(open_file())),
            unpack_dir,
            account_paths,
            parallel_divisions,
        )?,
        ArchiveFormat::TarGzip => unpack_snapshot_local(
            || GzDecoder::new(BufReader::new(open_file())),
            unpack_dir,
            account_paths,
            parallel_divisions,
        )?,
        ArchiveFormat::TarZstd => unpack_snapshot_local(
            || zstd::stream::read::Decoder::new(BufReader::new(open_file())).unwrap(),
            unpack_dir,
            account_paths,
            parallel_divisions,
        )?,
        ArchiveFormat::Tar => unpack_snapshot_local(
            || BufReader::new(open_file()),
            unpack_dir,
            account_paths,
            parallel_divisions,
        )?,
    };
    Ok(account_paths_map)
}

fn verify_unpacked_snapshots_dir_and_version(
    unpacked_snapshots_dir_and_version: &UnpackedSnapshotsDirAndVersion,
) -> Result<(SnapshotVersion, BankSnapshotInfo)> {
    info!(
        "snapshot version: {}",
        &unpacked_snapshots_dir_and_version.snapshot_version
    );

    let snapshot_version =
        SnapshotVersion::maybe_from_string(&unpacked_snapshots_dir_and_version.snapshot_version)
            .ok_or_else(|| {
                get_io_error(&format!(
                    "unsupported snapshot version: {}",
                    &unpacked_snapshots_dir_and_version.snapshot_version,
                ))
            })?;
    let mut bank_snapshot_infos =
        get_bank_snapshots(&unpacked_snapshots_dir_and_version.unpacked_snapshots_dir);
    if bank_snapshot_infos.len() > 1 {
        return Err(get_io_error("invalid snapshot format"));
    }
    bank_snapshot_infos.sort_unstable();
    let root_paths = bank_snapshot_infos
        .pop()
        .ok_or_else(|| get_io_error("No snapshots found in snapshots directory"))?;
    Ok((snapshot_version, root_paths))
}

#[allow(clippy::too_many_arguments)]
fn rebuild_bank_from_snapshots(
    full_snapshot_unpacked_snapshots_dir_and_version: &UnpackedSnapshotsDirAndVersion,
    incremental_snapshot_unpacked_snapshots_dir_and_version: Option<
        &UnpackedSnapshotsDirAndVersion,
    >,
    frozen_account_pubkeys: &[Pubkey],
    account_paths: &[PathBuf],
    unpacked_append_vec_map: UnpackedAppendVecMap,
    genesis_config: &GenesisConfig,
    debug_keys: Option<Arc<HashSet<Pubkey>>>,
    additional_builtins: Option<&Builtins>,
    account_secondary_indexes: AccountSecondaryIndexes,
    accounts_db_caching_enabled: bool,
    limit_load_slot_count_from_snapshot: Option<usize>,
    shrink_ratio: AccountShrinkThreshold,
    verify_index: bool,
) -> Result<Bank> {
    let (full_snapshot_version, full_snapshot_root_paths) =
        verify_unpacked_snapshots_dir_and_version(
            full_snapshot_unpacked_snapshots_dir_and_version,
        )?;
    let (incremental_snapshot_version, incremental_snapshot_root_paths) =
        if let Some(snapshot_unpacked_snapshots_dir_and_version) =
            incremental_snapshot_unpacked_snapshots_dir_and_version
        {
            let (snapshot_version, bank_snapshot_info) = verify_unpacked_snapshots_dir_and_version(
                snapshot_unpacked_snapshots_dir_and_version,
            )?;
            (Some(snapshot_version), Some(bank_snapshot_info))
        } else {
            (None, None)
        };
    info!(
        "Loading bank from full snapshot {} and incremental snapshot {:?}",
        full_snapshot_root_paths.snapshot_path.display(),
        incremental_snapshot_root_paths
            .as_ref()
            .map(|paths| paths.snapshot_path.display()),
    );

    let snapshot_root_paths = SnapshotRootPaths {
        full_snapshot_root_file_path: full_snapshot_root_paths.snapshot_path,
        incremental_snapshot_root_file_path: incremental_snapshot_root_paths
            .map(|root_paths| root_paths.snapshot_path),
    };

    let bank = deserialize_snapshot_data_files(&snapshot_root_paths, |mut snapshot_streams| {
        Ok(
            match incremental_snapshot_version.unwrap_or(full_snapshot_version) {
                SnapshotVersion::V1_2_0 => bank_from_streams(
                    SerdeStyle::Newer,
                    &mut snapshot_streams,
                    account_paths,
                    unpacked_append_vec_map,
                    genesis_config,
                    frozen_account_pubkeys,
                    debug_keys,
                    additional_builtins,
                    account_secondary_indexes,
                    accounts_db_caching_enabled,
                    limit_load_slot_count_from_snapshot,
                    shrink_ratio,
                    verify_index,
                ),
            }?,
        )
    })?;

    // The status cache is rebuilt from the latest snapshot.  So, if there's an incremental
    // snapshot, use that.  Otherwise use the full snapshot.
    let status_cache_path = incremental_snapshot_unpacked_snapshots_dir_and_version
        .map_or_else(
            || {
                full_snapshot_unpacked_snapshots_dir_and_version
                    .unpacked_snapshots_dir
                    .as_path()
            },
            |unpacked_snapshots_dir_and_version| {
                unpacked_snapshots_dir_and_version
                    .unpacked_snapshots_dir
                    .as_path()
            },
        )
        .join(SNAPSHOT_STATUS_CACHE_FILE_NAME);
    let slot_deltas = deserialize_snapshot_data_file(&status_cache_path, |stream| {
        info!(
            "Rebuilding status cache from {}",
            status_cache_path.display()
        );
        let slot_deltas: Vec<BankSlotDelta> = bincode::options()
            .with_limit(MAX_SNAPSHOT_DATA_FILE_SIZE)
            .with_fixint_encoding()
            .allow_trailing_bytes()
            .deserialize_from(stream)?;
        Ok(slot_deltas)
    })?;

    bank.src.append(&slot_deltas);

    info!("Loaded bank for slot: {}", bank.slot());
    Ok(bank)
}

fn get_snapshot_file_name(slot: Slot) -> String {
    slot.to_string()
}

fn get_bank_snapshots_dir<P: AsRef<Path>>(path: P, slot: Slot) -> PathBuf {
    path.as_ref().join(slot.to_string())
}

fn get_io_error(error: &str) -> SnapshotError {
    warn!("Snapshot Error: {:?}", error);
    SnapshotError::Io(IoError::new(ErrorKind::Other, error))
}

pub fn verify_snapshot_archive<P, Q, R>(
    snapshot_archive: P,
    snapshots_to_verify: Q,
    storages_to_verify: R,
    archive_format: ArchiveFormat,
) where
    P: AsRef<Path>,
    Q: AsRef<Path>,
    R: AsRef<Path>,
{
    let temp_dir = tempfile::TempDir::new().unwrap();
    let unpack_dir = temp_dir.path();
    untar_snapshot_in(
        snapshot_archive,
        unpack_dir,
        &[unpack_dir.to_path_buf()],
        archive_format,
        1,
    )
    .unwrap();

    // Check snapshots are the same
    let unpacked_snapshots = unpack_dir.join("snapshots");
    assert!(!dir_diff::is_different(&snapshots_to_verify, unpacked_snapshots).unwrap());

    // Check the account entries are the same
    let unpacked_accounts = unpack_dir.join("accounts");
    assert!(!dir_diff::is_different(&storages_to_verify, unpacked_accounts).unwrap());
}

/// Remove outdated bank snapshots
pub fn purge_old_bank_snapshots<P>(snapshots_dir: P)
where
    P: AsRef<Path>,
{
    let mut bank_snapshot_infos = get_bank_snapshots(&snapshots_dir);
    bank_snapshot_infos.sort_unstable();
    bank_snapshot_infos
        .into_iter()
        .rev()
        .skip(MAX_BANK_SNAPSHOTS)
        .for_each(|bank_snapshot_info| {
            let r = remove_bank_snapshot(bank_snapshot_info.slot, &snapshots_dir);
            if r.is_err() {
                warn!(
                    "Couldn't remove snapshot at: {}",
                    bank_snapshot_info.snapshot_path.display()
                );
            }
        })
}

/// Gather the necessary elements for a snapshot of the given `root_bank`
pub fn snapshot_bank(
    root_bank: &Bank,
    status_cache_slot_deltas: Vec<BankSlotDelta>,
    accounts_package_sender: &AccountsPackageSender,
    snapshots_dir: &Path,
    snapshot_package_output_path: &Path,
    snapshot_version: SnapshotVersion,
    archive_format: &ArchiveFormat,
    hash_for_testing: Option<Hash>,
) -> Result<()> {
    let storages: Vec<_> = root_bank.get_snapshot_storages();
    let mut add_snapshot_time = Measure::start("add-snapshot-ms");
    add_bank_snapshot(snapshots_dir, root_bank, &storages, snapshot_version)?;
    add_snapshot_time.stop();
    inc_new_counter_info!("add-snapshot-ms", add_snapshot_time.as_ms() as usize);

    // Package the relevant snapshots
    let highest_bank_snapshot_info = get_highest_bank_snapshot_info(snapshots_dir)
        .expect("no snapshots found in config snapshots_dir");

    let package = AccountsPackagePre::new_full_snapshot_package(
        root_bank,
        &highest_bank_snapshot_info,
        snapshots_dir,
        status_cache_slot_deltas,
        snapshot_package_output_path,
        storages,
        *archive_format,
        snapshot_version,
        hash_for_testing,
    )?;

    accounts_package_sender.send(package)?;

    Ok(())
}

/// Convenience function to create a full snapshot archive out of any Bank, regardless of state.
/// The Bank will be frozen during the process.
///
/// Requires:
///     - `bank` is complete
pub fn bank_to_full_snapshot_archive<P: AsRef<Path>, Q: AsRef<Path>>(
    snapshots_dir: P,
    bank: &Bank,
    snapshot_version: Option<SnapshotVersion>,
    snapshot_package_output_path: Q,
    archive_format: ArchiveFormat,
    thread_pool: Option<&ThreadPool>,
    maximum_snapshots_to_retain: usize,
) -> Result<PathBuf> {
    let snapshot_version = snapshot_version.unwrap_or_default();

    assert!(bank.is_complete());
    bank.squash(); // Bank may not be a root
    bank.force_flush_accounts_cache();
    bank.clean_accounts(true, false);
    bank.update_accounts_hash();
    bank.rehash(); // Bank accounts may have been manually modified by the caller

    let temp_dir = tempfile::tempdir_in(snapshots_dir)?;
    let storages = bank.get_snapshot_storages();
    let bank_snapshot_info = add_bank_snapshot(&temp_dir, bank, &storages, snapshot_version)?;

    package_process_and_archive_full_snapshot(
        bank,
        &bank_snapshot_info,
        &temp_dir,
        snapshot_package_output_path,
        storages,
        archive_format,
        snapshot_version,
        thread_pool,
        maximum_snapshots_to_retain,
    )
}

/// Convenience function to create an incremental snapshot archive out of any Bank, regardless of
/// state.  The Bank will be frozen during the process.
///
/// Requires:
///     - `bank` is complete
///     - `bank`'s slot is greater than `full_snapshot_slot`
pub fn bank_to_incremental_snapshot_archive<P: AsRef<Path>, Q: AsRef<Path>>(
    snapshots_dir: P,
    bank: &Bank,
    full_snapshot_slot: Slot,
    snapshot_version: Option<SnapshotVersion>,
    snapshot_package_output_path: Q,
    archive_format: ArchiveFormat,
    thread_pool: Option<&ThreadPool>,
    maximum_snapshots_to_retain: usize,
) -> Result<PathBuf> {
    let snapshot_version = snapshot_version.unwrap_or_default();

    assert!(bank.is_complete());
    assert!(bank.slot() > full_snapshot_slot);
    bank.squash(); // Bank may not be a root
    bank.force_flush_accounts_cache();
    bank.clean_accounts(true, false);
    bank.update_accounts_hash();
    bank.rehash(); // Bank accounts may have been manually modified by the caller

    let temp_dir = tempfile::tempdir_in(snapshots_dir)?;
    let storages = bank.get_incremental_snapshot_storages(full_snapshot_slot);
    let bank_snapshot_info = add_bank_snapshot(&temp_dir, bank, &storages, snapshot_version)?;

    package_process_and_archive_incremental_snapshot(
        bank,
        full_snapshot_slot,
        &bank_snapshot_info,
        &temp_dir,
        snapshot_package_output_path,
        storages,
        archive_format,
        snapshot_version,
        thread_pool,
        maximum_snapshots_to_retain,
    )
}

/// Helper function to hold shared code to package, process, and archive full snapshots
pub fn package_process_and_archive_full_snapshot(
    bank: &Bank,
    bank_snapshot_info: &BankSnapshotInfo,
    snapshots_dir: impl AsRef<Path>,
    snapshot_package_output_path: impl AsRef<Path>,
    snapshot_storages: SnapshotStorages,
    archive_format: ArchiveFormat,
    snapshot_version: SnapshotVersion,
    thread_pool: Option<&ThreadPool>,
    maximum_snapshots_to_retain: usize,
) -> Result<PathBuf> {
    let package = AccountsPackagePre::new_full_snapshot_package(
        bank,
        bank_snapshot_info,
        snapshots_dir,
        bank.src.slot_deltas(&bank.src.roots()),
        snapshot_package_output_path,
        snapshot_storages,
        archive_format,
        snapshot_version,
        None,
    )?;

    process_and_archive_snapshot_package_pre(
        package,
        thread_pool,
        None,
        maximum_snapshots_to_retain,
    )
}

/// Helper function to hold shared code to package, process, and archive incremental snapshots
#[allow(clippy::too_many_arguments)]
pub fn package_process_and_archive_incremental_snapshot(
    bank: &Bank,
    incremental_snapshot_base_slot: Slot,
    bank_snapshot_info: &BankSnapshotInfo,
    snapshots_dir: impl AsRef<Path>,
    snapshot_package_output_path: impl AsRef<Path>,
    snapshot_storages: SnapshotStorages,
    archive_format: ArchiveFormat,
    snapshot_version: SnapshotVersion,
    thread_pool: Option<&ThreadPool>,
    maximum_snapshots_to_retain: usize,
) -> Result<PathBuf> {
    let package = AccountsPackagePre::new_incremental_snapshot_package(
        bank,
        incremental_snapshot_base_slot,
        bank_snapshot_info,
        snapshots_dir,
        bank.src.slot_deltas(&bank.src.roots()),
        snapshot_package_output_path,
        snapshot_storages,
        archive_format,
        snapshot_version,
        None,
    )?;

    process_and_archive_snapshot_package_pre(
        package,
        thread_pool,
        Some(incremental_snapshot_base_slot),
        maximum_snapshots_to_retain,
    )
}

/// Helper function to hold shared code to process and archive snapshot packages
fn process_and_archive_snapshot_package_pre(
    package_pre: AccountsPackagePre,
    thread_pool: Option<&ThreadPool>,
    incremental_snapshot_base_slot: Option<Slot>,
    maximum_snapshots_to_retain: usize,
) -> Result<PathBuf> {
    let package =
        process_accounts_package_pre(package_pre, thread_pool, incremental_snapshot_base_slot);

    archive_snapshot_package(&package, maximum_snapshots_to_retain)?;

    Ok(package.tar_output_file)
}

pub fn process_accounts_package_pre(
    accounts_package: AccountsPackagePre,
    thread_pool: Option<&ThreadPool>,
    incremental_snapshot_base_slot: Option<Slot>,
) -> AccountsPackage {
    let mut time = Measure::start("hash");

    let hash = accounts_package.hash; // temporarily remaining here
    if let Some(expected_hash) = accounts_package.hash_for_testing {
        let sorted_storages = SortedStorages::new(&accounts_package.storages);
        let (hash, lamports) = AccountsDb::calculate_accounts_hash_without_index(
            &sorted_storages,
            thread_pool,
            crate::accounts_hash::HashStats::default(),
            false,
            None,
        )
        .unwrap();

        assert_eq!(accounts_package.expected_capitalization, lamports);

        assert_eq!(expected_hash, hash);
    };
    time.stop();

    datapoint_info!(
        "accounts_hash_verifier",
        ("calculate_hash", time.as_us(), i64),
    );

    let tar_output_file = match incremental_snapshot_base_slot {
        None => build_full_snapshot_archive_path(
            accounts_package.snapshot_output_dir,
            accounts_package.slot,
            &hash,
            accounts_package.archive_format,
        ),
        Some(incremental_snapshot_base_slot) => build_incremental_snapshot_archive_path(
            accounts_package.snapshot_output_dir,
            incremental_snapshot_base_slot,
            accounts_package.slot,
            &hash,
            accounts_package.archive_format,
        ),
    };

    AccountsPackage::new(
        accounts_package.slot,
        accounts_package.block_height,
        accounts_package.slot_deltas,
        accounts_package.snapshot_links,
        accounts_package.storages,
        tar_output_file,
        hash,
        accounts_package.archive_format,
        accounts_package.snapshot_version,
    )
}

#[cfg(test)]
mod tests {
    use super::*;
    use assert_matches::assert_matches;
    use bincode::{deserialize_from, serialize_into};
    use solana_sdk::{
        genesis_config::create_genesis_config,
        signature::{Keypair, Signer},
    };
    use std::mem::size_of;

    #[test]
    fn test_serialize_snapshot_data_file_under_limit() {
        let temp_dir = tempfile::TempDir::new().unwrap();
        let expected_consumed_size = size_of::<u32>() as u64;
        let consumed_size = serialize_snapshot_data_file_capped(
            &temp_dir.path().join("data-file"),
            expected_consumed_size,
            |stream| {
                serialize_into(stream, &2323_u32)?;
                Ok(())
            },
        )
        .unwrap();
        assert_eq!(consumed_size, expected_consumed_size);
    }

    #[test]
    fn test_serialize_snapshot_data_file_over_limit() {
        let temp_dir = tempfile::TempDir::new().unwrap();
        let expected_consumed_size = size_of::<u32>() as u64;
        let result = serialize_snapshot_data_file_capped(
            &temp_dir.path().join("data-file"),
            expected_consumed_size - 1,
            |stream| {
                serialize_into(stream, &2323_u32)?;
                Ok(())
            },
        );
        assert_matches!(result, Err(SnapshotError::Io(ref message)) if message.to_string().starts_with("too large snapshot data file to serialize"));
    }

    #[test]
    fn test_deserialize_snapshot_data_file_under_limit() {
        let expected_data = 2323_u32;
        let expected_consumed_size = size_of::<u32>() as u64;

        let temp_dir = tempfile::TempDir::new().unwrap();
        serialize_snapshot_data_file_capped(
            &temp_dir.path().join("data-file"),
            expected_consumed_size,
            |stream| {
                serialize_into(stream, &expected_data)?;
                Ok(())
            },
        )
        .unwrap();

        let snapshot_root_paths = SnapshotRootPaths {
            full_snapshot_root_file_path: temp_dir.path().join("data-file"),
            incremental_snapshot_root_file_path: None,
        };

        let actual_data = deserialize_snapshot_data_files_capped(
            &snapshot_root_paths,
            expected_consumed_size,
            |stream| {
                Ok(deserialize_from::<_, u32>(
                    &mut stream.full_snapshot_stream,
                )?)
            },
        )
        .unwrap();
        assert_eq!(actual_data, expected_data);
    }

    #[test]
    fn test_deserialize_snapshot_data_file_over_limit() {
        let expected_data = 2323_u32;
        let expected_consumed_size = size_of::<u32>() as u64;

        let temp_dir = tempfile::TempDir::new().unwrap();
        serialize_snapshot_data_file_capped(
            &temp_dir.path().join("data-file"),
            expected_consumed_size,
            |stream| {
                serialize_into(stream, &expected_data)?;
                Ok(())
            },
        )
        .unwrap();

        let snapshot_root_paths = SnapshotRootPaths {
            full_snapshot_root_file_path: temp_dir.path().join("data-file"),
            incremental_snapshot_root_file_path: None,
        };

        let result = deserialize_snapshot_data_files_capped(
            &snapshot_root_paths,
            expected_consumed_size - 1,
            |stream| {
                Ok(deserialize_from::<_, u32>(
                    &mut stream.full_snapshot_stream,
                )?)
            },
        );
        assert_matches!(result, Err(SnapshotError::Io(ref message)) if message.to_string().starts_with("too large snapshot data file to deserialize"));
    }

    #[test]
    fn test_deserialize_snapshot_data_file_extra_data() {
        let expected_data = 2323_u32;
        let expected_consumed_size = size_of::<u32>() as u64;

        let temp_dir = tempfile::TempDir::new().unwrap();
        serialize_snapshot_data_file_capped(
            &temp_dir.path().join("data-file"),
            expected_consumed_size * 2,
            |stream| {
                serialize_into(stream.by_ref(), &expected_data)?;
                serialize_into(stream.by_ref(), &expected_data)?;
                Ok(())
            },
        )
        .unwrap();

        let snapshot_root_paths = SnapshotRootPaths {
            full_snapshot_root_file_path: temp_dir.path().join("data-file"),
            incremental_snapshot_root_file_path: None,
        };

        let result = deserialize_snapshot_data_files_capped(
            &snapshot_root_paths,
            expected_consumed_size * 2,
            |stream| {
                Ok(deserialize_from::<_, u32>(
                    &mut stream.full_snapshot_stream,
                )?)
            },
        );
        assert_matches!(result, Err(SnapshotError::Io(ref message)) if message.to_string().starts_with("invalid snapshot data file"));
    }

    #[test]
    fn test_parse_full_snapshot_archive_filename() {
        assert_eq!(
            parse_full_snapshot_archive_filename(&format!(
                "snapshot-42-{}.tar.bz2",
                Hash::default()
            ))
            .unwrap(),
            (42, Hash::default(), ArchiveFormat::TarBzip2)
        );
        assert_eq!(
            parse_full_snapshot_archive_filename(&format!(
                "snapshot-43-{}.tar.zst",
                Hash::default()
            ))
            .unwrap(),
            (43, Hash::default(), ArchiveFormat::TarZstd)
        );
        assert_eq!(
            parse_full_snapshot_archive_filename(&format!("snapshot-44-{}.tar", Hash::default()))
                .unwrap(),
            (44, Hash::default(), ArchiveFormat::Tar)
        );

        assert!(parse_full_snapshot_archive_filename("invalid").is_err());
        assert!(
            parse_full_snapshot_archive_filename("snapshot-bad!slot-bad!hash.bad!ext").is_err()
        );

        assert!(
            parse_full_snapshot_archive_filename("snapshot-12345678-bad!hash.bad!ext").is_err()
        );
        assert!(parse_full_snapshot_archive_filename(&format!(
            "snapshot-12345678-{}.bad!ext",
            Hash::new_unique()
        ))
        .is_err());
        assert!(parse_full_snapshot_archive_filename("snapshot-12345678-bad!hash.tar").is_err());

        assert!(parse_full_snapshot_archive_filename(&format!(
            "snapshot-bad!slot-{}.bad!ext",
            Hash::new_unique()
        ))
        .is_err());
        assert!(parse_full_snapshot_archive_filename(&format!(
            "snapshot-12345678-{}.bad!ext",
            Hash::new_unique()
        ))
        .is_err());
        assert!(parse_full_snapshot_archive_filename(&format!(
            "snapshot-bad!slot-{}.tar",
            Hash::new_unique()
        ))
        .is_err());

        assert!(parse_full_snapshot_archive_filename("snapshot-bad!slot-bad!hash.tar").is_err());
        assert!(parse_full_snapshot_archive_filename("snapshot-12345678-bad!hash.tar").is_err());
        assert!(parse_full_snapshot_archive_filename(&format!(
            "snapshot-bad!slot-{}.tar",
            Hash::new_unique()
        ))
        .is_err());
    }

    #[test]
    fn test_parse_incremental_snapshot_archive_filename() {
        solana_logger::setup();
        assert_eq!(
            parse_incremental_snapshot_archive_filename(&format!(
                "incremental-snapshot-42-123-{}.tar.bz2",
                Hash::default()
            ))
            .unwrap(),
            (42, 123, Hash::default(), ArchiveFormat::TarBzip2)
        );
        assert_eq!(
            parse_incremental_snapshot_archive_filename(&format!(
                "incremental-snapshot-43-234-{}.tar.zst",
                Hash::default()
            ))
            .unwrap(),
            (43, 234, Hash::default(), ArchiveFormat::TarZstd)
        );
        assert_eq!(
            parse_incremental_snapshot_archive_filename(&format!(
                "incremental-snapshot-44-345-{}.tar",
                Hash::default()
            ))
            .unwrap(),
            (44, 345, Hash::default(), ArchiveFormat::Tar)
        );

        assert!(parse_incremental_snapshot_archive_filename("invalid").is_err());
        assert!(parse_incremental_snapshot_archive_filename(&format!(
            "snapshot-42-{}.tar",
            Hash::new_unique()
        ))
        .is_err());
        assert!(parse_incremental_snapshot_archive_filename(
            "incremental-snapshot-bad!slot-bad!slot-bad!hash.bad!ext"
        )
        .is_err());

        assert!(parse_incremental_snapshot_archive_filename(&format!(
            "incremental-snapshot-bad!slot-56785678-{}.tar",
            Hash::new_unique()
        ))
        .is_err());

        assert!(parse_incremental_snapshot_archive_filename(&format!(
            "incremental-snapshot-12345678-bad!slot-{}.tar",
            Hash::new_unique()
        ))
        .is_err());

        assert!(parse_incremental_snapshot_archive_filename(
            "incremental-snapshot-12341234-56785678-bad!HASH.tar"
        )
        .is_err());

        assert!(parse_incremental_snapshot_archive_filename(&format!(
            "incremental-snapshot-12341234-56785678-{}.bad!ext",
            Hash::new_unique()
        ))
        .is_err());
    }

    #[test]
    fn test_check_are_snapshots_compatible() {
        solana_logger::setup();
        let slot1: Slot = 1234;
        let slot2: Slot = 5678;
        let slot3: Slot = 999_999;

        assert!(check_are_snapshots_compatible(
            &format!("/dir/snapshot-{}-{}.tar", slot1, Hash::new_unique()),
            &format!(
                "/dir/incremental-snapshot-{}-{}-{}.tar",
                slot1,
                slot2,
                Hash::new_unique()
            ),
        )
        .is_ok());

        assert!(check_are_snapshots_compatible(
            &format!("/dir/snapshot-{}-{}.tar", slot1, Hash::new_unique()),
            &format!(
                "/dir/incremental-snapshot-{}-{}-{}.tar",
                slot2,
                slot3,
                Hash::new_unique()
            ),
        )
        .is_err());
    }

    /// A test heler function that creates bank snapshot files
    fn common_create_bank_snapshot_files(snapshots_dir: &Path, min_slot: Slot, max_slot: Slot) {
        for slot in min_slot..max_slot {
            let snapshot_dir = get_bank_snapshots_dir(snapshots_dir, slot);
            fs::create_dir_all(&snapshot_dir).unwrap();

            let snapshot_filename = get_snapshot_file_name(slot);
            let snapshot_path = snapshot_dir.join(snapshot_filename);
            File::create(snapshot_path).unwrap();
        }
    }

    #[test]
    fn test_get_bank_snapshot_infos() {
        solana_logger::setup();
        let temp_snapshots_dir = tempfile::TempDir::new().unwrap();
        let min_slot = 10;
        let max_slot = 20;
        common_create_bank_snapshot_files(temp_snapshots_dir.path(), min_slot, max_slot);

        let bank_snapshot_infos = get_bank_snapshots(temp_snapshots_dir.path());
        assert_eq!(bank_snapshot_infos.len() as Slot, max_slot - min_slot);
    }

    #[test]
    fn test_get_highest_bank_snapshot_info() {
        solana_logger::setup();
        let temp_snapshots_dir = tempfile::TempDir::new().unwrap();
        let min_slot = 99;
        let max_slot = 123;
        common_create_bank_snapshot_files(temp_snapshots_dir.path(), min_slot, max_slot);

        let highest_bank_snapshot_info = get_highest_bank_snapshot_info(temp_snapshots_dir.path());
        assert!(highest_bank_snapshot_info.is_some());
        assert_eq!(highest_bank_snapshot_info.unwrap().slot, max_slot - 1);
    }

    /// A test helper function that creates full and incremental snapshot archive files.  Creates
    /// full snapshot files in the range (`min_full_snapshot_slot`, `max_full_snapshot_slot`], and
    /// incremental snapshot files in the range (`min_incremental_snapshot_slot`,
    /// `max_incremental_snapshot_slot`].  Additionally, "bad" files are created for both full and
    /// incremental snapshots to ensure the tests properly filter them out.
    fn common_create_snapshot_archive_files(
        snapshot_archives_dir: &Path,
        min_full_snapshot_slot: Slot,
        max_full_snapshot_slot: Slot,
        min_incremental_snapshot_slot: Slot,
        max_incremental_snapshot_slot: Slot,
    ) {
        for full_snapshot_slot in min_full_snapshot_slot..max_full_snapshot_slot {
            for incremental_snapshot_slot in
                min_incremental_snapshot_slot..max_incremental_snapshot_slot
            {
                let snapshot_filename = format!(
                    "incremental-snapshot-{}-{}-{}.tar",
                    full_snapshot_slot,
                    incremental_snapshot_slot,
                    Hash::default()
                );
                let snapshot_filepath = snapshot_archives_dir.join(snapshot_filename);
                File::create(snapshot_filepath).unwrap();
            }

            let snapshot_filename =
                format!("snapshot-{}-{}.tar", full_snapshot_slot, Hash::default());
            let snapshot_filepath = snapshot_archives_dir.join(snapshot_filename);
            File::create(snapshot_filepath).unwrap();

            // Add in an incremental snapshot with a bad filename and high slot to ensure filename are filtered and sorted correctly
            let bad_filename = format!(
                "incremental-snapshot-{}-{}-bad!hash.tar",
                full_snapshot_slot,
                max_incremental_snapshot_slot + 1,
            );
            let bad_filepath = snapshot_archives_dir.join(bad_filename);
            File::create(bad_filepath).unwrap();
        }

        // Add in a snapshot with a bad filename and high slot to ensure filename are filtered and
        // sorted correctly
        let bad_filename = format!("snapshot-{}-bad!hash.tar", max_full_snapshot_slot + 1);
        let bad_filepath = snapshot_archives_dir.join(bad_filename);
        File::create(bad_filepath).unwrap();
    }

    #[test]
    fn test_get_full_snapshot_archives() {
        solana_logger::setup();
        let temp_snapshot_archives_dir = tempfile::TempDir::new().unwrap();
        let min_slot = 123;
        let max_slot = 456;
        common_create_snapshot_archive_files(
            temp_snapshot_archives_dir.path(),
            min_slot,
            max_slot,
            0,
            0,
        );

        let snapshot_archives = get_full_snapshot_archives(temp_snapshot_archives_dir);
        assert_eq!(snapshot_archives.len() as Slot, max_slot - min_slot);
    }

    #[test]
    fn test_get_incremental_snapshot_archives() {
        solana_logger::setup();
        let temp_snapshot_archives_dir = tempfile::TempDir::new().unwrap();
        let min_full_snapshot_slot = 12;
        let max_full_snapshot_slot = 23;
        let min_incremental_snapshot_slot = 34;
        let max_incremental_snapshot_slot = 45;
        common_create_snapshot_archive_files(
            temp_snapshot_archives_dir.path(),
            min_full_snapshot_slot,
            max_full_snapshot_slot,
            min_incremental_snapshot_slot,
            max_incremental_snapshot_slot,
        );

        let incremental_snapshot_archives =
            get_incremental_snapshot_archives(temp_snapshot_archives_dir);
        assert_eq!(
            incremental_snapshot_archives.len() as Slot,
            (max_full_snapshot_slot - min_full_snapshot_slot)
                * (max_incremental_snapshot_slot - min_incremental_snapshot_slot)
        );
    }

    #[test]
    fn test_get_highest_full_snapshot_archive_slot() {
        solana_logger::setup();
        let temp_snapshot_archives_dir = tempfile::TempDir::new().unwrap();
        let min_slot = 123;
        let max_slot = 456;
        common_create_snapshot_archive_files(
            temp_snapshot_archives_dir.path(),
            min_slot,
            max_slot,
            0,
            0,
        );

        assert_eq!(
            get_highest_full_snapshot_archive_slot(temp_snapshot_archives_dir.path()),
            Some(max_slot - 1)
        );
    }

    #[test]
    fn test_get_highest_incremental_snapshot_slot() {
        solana_logger::setup();
        let temp_snapshot_archives_dir = tempfile::TempDir::new().unwrap();
        let min_full_snapshot_slot = 12;
        let max_full_snapshot_slot = 23;
        let min_incremental_snapshot_slot = 34;
        let max_incremental_snapshot_slot = 45;
        common_create_snapshot_archive_files(
            temp_snapshot_archives_dir.path(),
            min_full_snapshot_slot,
            max_full_snapshot_slot,
            min_incremental_snapshot_slot,
            max_incremental_snapshot_slot,
        );

        for full_snapshot_slot in min_full_snapshot_slot..max_full_snapshot_slot {
            assert_eq!(
                get_highest_incremental_snapshot_archive_slot(
                    temp_snapshot_archives_dir.path(),
                    full_snapshot_slot
                ),
                Some(max_incremental_snapshot_slot - 1)
            );
        }

        assert_eq!(
            get_highest_incremental_snapshot_archive_slot(
                temp_snapshot_archives_dir.path(),
                max_full_snapshot_slot
            ),
            None
        );
    }

    fn common_test_purge_old_snapshot_archives(
        snapshot_names: &[&String],
        maximum_snapshots_to_retain: usize,
        expected_snapshots: &[&String],
    ) {
        let temp_snap_dir = tempfile::TempDir::new().unwrap();

        for snap_name in snapshot_names {
            let snap_path = temp_snap_dir.path().join(&snap_name);
            let mut _snap_file = File::create(snap_path);
        }
        purge_old_snapshot_archives(temp_snap_dir.path(), maximum_snapshots_to_retain);

        let mut retained_snaps = HashSet::new();
        for entry in fs::read_dir(temp_snap_dir.path()).unwrap() {
            let entry_path_buf = entry.unwrap().path();
            let entry_path = entry_path_buf.as_path();
            let snapshot_name = entry_path
                .file_name()
                .unwrap()
                .to_str()
                .unwrap()
                .to_string();
            retained_snaps.insert(snapshot_name);
        }

        for snap_name in expected_snapshots {
            assert!(retained_snaps.contains(snap_name.as_str()));
        }
        assert!(retained_snaps.len() == expected_snapshots.len());
    }

    #[test]
    fn test_purge_old_full_snapshot_archives() {
        // Create 3 snapshots, retaining 1,
        // expecting the oldest 1 and the newest 1 are retained
        let snap1_name = format!("snapshot-1-{}.tar.zst", Hash::default());
        let snap2_name = format!("snapshot-3-{}.tar.zst", Hash::default());
        let snap3_name = format!("snapshot-50-{}.tar.zst", Hash::default());
        let snapshot_names = vec![&snap1_name, &snap2_name, &snap3_name];
        let expected_snapshots = vec![&snap1_name, &snap3_name];
        common_test_purge_old_snapshot_archives(&snapshot_names, 1, &expected_snapshots);

        // retaining 0, the expectation is the same as for 1, as at least 1 newest is expected to be retained
        common_test_purge_old_snapshot_archives(&snapshot_names, 0, &expected_snapshots);

        // retaining 2, all three should be retained
        let expected_snapshots = vec![&snap1_name, &snap2_name, &snap3_name];
        common_test_purge_old_snapshot_archives(&snapshot_names, 2, &expected_snapshots);
    }

    #[test]
    fn test_purge_old_incremental_snapshot_archives() {
        let snapshot_archives_dir = tempfile::TempDir::new().unwrap();

        for snapshot_filename in [
            format!("snapshot-100-{}.tar", Hash::default()),
            format!("snapshot-200-{}.tar", Hash::default()),
            format!("incremental-snapshot-100-120-{}.tar", Hash::default()),
            format!("incremental-snapshot-100-140-{}.tar", Hash::default()),
            format!("incremental-snapshot-100-160-{}.tar", Hash::default()),
            format!("incremental-snapshot-100-180-{}.tar", Hash::default()),
            format!("incremental-snapshot-200-220-{}.tar", Hash::default()),
            format!("incremental-snapshot-200-240-{}.tar", Hash::default()),
            format!("incremental-snapshot-200-260-{}.tar", Hash::default()),
            format!("incremental-snapshot-200-280-{}.tar", Hash::default()),
        ] {
            let snapshot_path = snapshot_archives_dir.path().join(&snapshot_filename);
            File::create(snapshot_path).unwrap();
        }

        purge_old_snapshot_archives(snapshot_archives_dir.path(), std::usize::MAX);

        let remaining_incremental_snapshot_archives =
            get_incremental_snapshot_archives(snapshot_archives_dir.path());
        assert_eq!(remaining_incremental_snapshot_archives.len(), 4);
        for archive in &remaining_incremental_snapshot_archives {
            assert_eq!(*archive.base_slot(), 200);
        }
    }

    #[test]
    fn test_purge_all_incremental_snapshot_archives_when_no_full_snapshot_archives() {
        let snapshot_archives_dir = tempfile::TempDir::new().unwrap();

        for snapshot_filename in [
            format!("incremental-snapshot-100-120-{}.tar", Hash::default()),
            format!("incremental-snapshot-100-140-{}.tar", Hash::default()),
            format!("incremental-snapshot-100-160-{}.tar", Hash::default()),
            format!("incremental-snapshot-100-180-{}.tar", Hash::default()),
            format!("incremental-snapshot-200-220-{}.tar", Hash::default()),
            format!("incremental-snapshot-200-240-{}.tar", Hash::default()),
            format!("incremental-snapshot-200-260-{}.tar", Hash::default()),
            format!("incremental-snapshot-200-280-{}.tar", Hash::default()),
        ] {
            let snapshot_path = snapshot_archives_dir.path().join(&snapshot_filename);
            File::create(snapshot_path).unwrap();
        }

        purge_old_snapshot_archives(snapshot_archives_dir.path(), std::usize::MAX);

        let remaining_incremental_snapshot_archives =
            get_incremental_snapshot_archives(snapshot_archives_dir.path());
        assert!(remaining_incremental_snapshot_archives.is_empty());
    }

    /// Test roundtrip of bank to a full snapshot, then back again.  This test creates the simplest
    /// bank possible, so the contents of the snapshot archive will be quite minimal.
    #[test]
    fn test_roundtrip_bank_to_and_from_full_snapshot_simple() {
        solana_logger::setup();
        let genesis_config = GenesisConfig::default();
        let original_bank = Bank::new(&genesis_config);

        while !original_bank.is_complete() {
            original_bank.register_tick(&Hash::new_unique());
        }

        let accounts_dir = tempfile::TempDir::new().unwrap();
        let snapshots_dir = tempfile::TempDir::new().unwrap();
        let snapshot_archives_dir = tempfile::TempDir::new().unwrap();
        let snapshot_archive_format = ArchiveFormat::Tar;

        let snapshot_archive_path = bank_to_full_snapshot_archive(
            snapshots_dir.path(),
            &original_bank,
            None,
            snapshot_archives_dir.path(),
            snapshot_archive_format,
            None,
            1,
        )
        .unwrap();

        let (roundtrip_bank, _) = bank_from_snapshot_archives(
            &[PathBuf::from(accounts_dir.path())],
            &[],
            snapshots_dir.path(),
            &snapshot_archive_path,
            None,
            snapshot_archive_format,
            &genesis_config,
            None,
            None,
            AccountSecondaryIndexes::default(),
            false,
            None,
            AccountShrinkThreshold::default(),
            false,
            false,
        )
        .unwrap();

        assert_eq!(original_bank, roundtrip_bank);
    }

    /// Test roundtrip of bank to a full snapshot, then back again.  This test is more involved
    /// than the simple version above; creating multiple banks over multiple slots and doing
    /// multiple transfers.  So this full snapshot should contain more data.
    #[test]
    fn test_roundtrip_bank_to_and_from_snapshot_complex() {
        solana_logger::setup();
        let collector = Pubkey::new_unique();
        let key1 = Keypair::new();
        let key2 = Keypair::new();
        let key3 = Keypair::new();
        let key4 = Keypair::new();
        let key5 = Keypair::new();

        let (genesis_config, mint_keypair) = create_genesis_config(1_000_000);
        let bank0 = Arc::new(Bank::new(&genesis_config));
        bank0.transfer(1, &mint_keypair, &key1.pubkey()).unwrap();
        bank0.transfer(2, &mint_keypair, &key2.pubkey()).unwrap();
        bank0.transfer(3, &mint_keypair, &key3.pubkey()).unwrap();
        while !bank0.is_complete() {
            bank0.register_tick(&Hash::new_unique());
        }

        let slot = 1;
        let bank1 = Arc::new(Bank::new_from_parent(&bank0, &collector, slot));
        bank1.transfer(3, &mint_keypair, &key3.pubkey()).unwrap();
        bank1.transfer(4, &mint_keypair, &key4.pubkey()).unwrap();
        bank1.transfer(5, &mint_keypair, &key5.pubkey()).unwrap();
        while !bank1.is_complete() {
            bank1.register_tick(&Hash::new_unique());
        }

        let slot = slot + 1;
        let bank2 = Arc::new(Bank::new_from_parent(&bank1, &collector, slot));
        bank2.transfer(1, &mint_keypair, &key1.pubkey()).unwrap();
        while !bank2.is_complete() {
            bank2.register_tick(&Hash::new_unique());
        }

        let slot = slot + 1;
        let bank3 = Arc::new(Bank::new_from_parent(&bank2, &collector, slot));
        bank3.transfer(1, &mint_keypair, &key1.pubkey()).unwrap();
        while !bank3.is_complete() {
            bank3.register_tick(&Hash::new_unique());
        }

        let slot = slot + 1;
        let bank4 = Arc::new(Bank::new_from_parent(&bank3, &collector, slot));
        bank4.transfer(1, &mint_keypair, &key1.pubkey()).unwrap();
        while !bank4.is_complete() {
            bank4.register_tick(&Hash::new_unique());
        }

        let accounts_dir = tempfile::TempDir::new().unwrap();
        let snapshots_dir = tempfile::TempDir::new().unwrap();
        let snapshot_archives_dir = tempfile::TempDir::new().unwrap();
        let snapshot_archive_format = ArchiveFormat::Tar;

        let full_snapshot_archive_path = bank_to_full_snapshot_archive(
            snapshots_dir.path(),
            &bank4,
            None,
            snapshot_archives_dir.path(),
            snapshot_archive_format,
            None,
            std::usize::MAX,
        )
        .unwrap();

        let (roundtrip_bank, _) = bank_from_snapshot_archives(
            &[PathBuf::from(accounts_dir.path())],
            &[],
            snapshots_dir.path(),
            &full_snapshot_archive_path,
            None,
            snapshot_archive_format,
            &genesis_config,
            None,
            None,
            AccountSecondaryIndexes::default(),
            false,
            None,
            AccountShrinkThreshold::default(),
            false,
            false,
        )
        .unwrap();

        assert_eq!(*bank4, roundtrip_bank);
    }

    /// Test roundtrip of bank to snapshots, then back again, with incremental snapshots.  In this
    /// version, build up a few slots and take a full snapshot.  Continue on a few more slots and
    /// take an incremental snapshot.  Rebuild the bank from both the incremental snapshot and full
    /// snapshot.
    ///
    /// For the full snapshot, touch all the accounts, but only one for the incremental snapshot.
    /// This is intended to mimic the real behavior of transactions, where only a small number of
    /// accounts are modified often, which are captured by the incremental snapshot.  The majority
    /// of the accounts are not modified often, and are captured by the full snapshot.
    #[test]
    fn test_roundtrip_bank_to_and_from_incremental_snapshot() {
        solana_logger::setup();
        let collector = Pubkey::new_unique();
        let key1 = Keypair::new();
        let key2 = Keypair::new();
        let key3 = Keypair::new();
        let key4 = Keypair::new();
        let key5 = Keypair::new();

        let (genesis_config, mint_keypair) = create_genesis_config(1_000_000);
        let bank0 = Arc::new(Bank::new(&genesis_config));
        bank0.transfer(1, &mint_keypair, &key1.pubkey()).unwrap();
        bank0.transfer(2, &mint_keypair, &key2.pubkey()).unwrap();
        bank0.transfer(3, &mint_keypair, &key3.pubkey()).unwrap();
        while !bank0.is_complete() {
            bank0.register_tick(&Hash::new_unique());
        }

        let slot = 1;
        let bank1 = Arc::new(Bank::new_from_parent(&bank0, &collector, slot));
        bank1.transfer(3, &mint_keypair, &key3.pubkey()).unwrap();
        bank1.transfer(4, &mint_keypair, &key4.pubkey()).unwrap();
        bank1.transfer(5, &mint_keypair, &key5.pubkey()).unwrap();
        while !bank1.is_complete() {
            bank1.register_tick(&Hash::new_unique());
        }

        let accounts_dir = tempfile::TempDir::new().unwrap();
        let snapshots_dir = tempfile::TempDir::new().unwrap();
        let snapshot_archives_dir = tempfile::TempDir::new().unwrap();
        let snapshot_archive_format = ArchiveFormat::Tar;

        let full_snapshot_slot = slot;
        let full_snapshot_archive_path = bank_to_full_snapshot_archive(
            snapshots_dir.path(),
            &bank1,
            None,
            snapshot_archives_dir.path(),
            snapshot_archive_format,
            None,
            std::usize::MAX,
        )
        .unwrap();

        let slot = slot + 1;
        let bank2 = Arc::new(Bank::new_from_parent(&bank1, &collector, slot));
        bank2.transfer(1, &mint_keypair, &key1.pubkey()).unwrap();
        while !bank2.is_complete() {
            bank2.register_tick(&Hash::new_unique());
        }

        let slot = slot + 1;
        let bank3 = Arc::new(Bank::new_from_parent(&bank2, &collector, slot));
        bank3.transfer(1, &mint_keypair, &key1.pubkey()).unwrap();
        while !bank3.is_complete() {
            bank3.register_tick(&Hash::new_unique());
        }

        let slot = slot + 1;
        let bank4 = Arc::new(Bank::new_from_parent(&bank3, &collector, slot));
        bank4.transfer(1, &mint_keypair, &key1.pubkey()).unwrap();
        while !bank4.is_complete() {
            bank4.register_tick(&Hash::new_unique());
        }

        let incremental_snapshot_archive_path = bank_to_incremental_snapshot_archive(
            snapshots_dir.path(),
            &bank4,
            full_snapshot_slot,
            None,
            snapshot_archives_dir.path(),
            snapshot_archive_format,
            None,
            std::usize::MAX,
        )
        .unwrap();

        let (roundtrip_bank, _) = bank_from_snapshot_archives(
            &[PathBuf::from(accounts_dir.path())],
            &[],
            snapshots_dir.path(),
            &full_snapshot_archive_path,
            Some(&incremental_snapshot_archive_path),
            snapshot_archive_format,
            &genesis_config,
            None,
            None,
            AccountSecondaryIndexes::default(),
            false,
            None,
            AccountShrinkThreshold::default(),
            false,
            false,
        )
        .unwrap();

        assert_eq!(*bank4, roundtrip_bank);
    }
}