use core::borrow::Borrow;
use std::sync::Arc;
use log::warn;
use serde_bytes::ByteBuf;
use sled::Transactional;
use garage_util::background::BackgroundRunner;
use garage_util::data::*;
use garage_util::error::*;
use crate::crdt::CRDT;
use crate::merkle::*;
use crate::schema::*;
pub struct TableData<F: TableSchema> {
pub name: String,
pub instance: F,
pub store: sled::Tree,
pub gc_todo: sled::Tree,
pub merkle_updater: Arc<MerkleUpdater>,
}
impl<F> TableData<F>
where
F: TableSchema,
{
pub fn new(
name: String,
instance: F,
db: &sled::Db,
background: Arc<BackgroundRunner>,
) -> Arc<Self> {
let store = db
.open_tree(&format!("{}:table", name))
.expect("Unable to open DB tree");
let merkle_todo_store = db
.open_tree(&format!("{}:merkle_todo", name))
.expect("Unable to open DB Merkle TODO tree");
let merkle_tree_store = db
.open_tree(&format!("{}:merkle_tree", name))
.expect("Unable to open DB Merkle tree tree");
let gc_todo = db
.open_tree(&format!("{}:gc_todo", name))
.expect("Unable to open DB tree");
let merkle_updater = MerkleUpdater::launch(
name.clone(),
background,
merkle_todo_store,
merkle_tree_store,
);
Arc::new(Self {
name,
instance,
store,
gc_todo,
merkle_updater,
})
}
// Read functions
pub fn read_entry(&self, p: &F::P, s: &F::S) -> Result<Option<ByteBuf>, Error> {
let tree_key = self.tree_key(p, s);
if let Some(bytes) = self.store.get(&tree_key)? {
Ok(Some(ByteBuf::from(bytes.to_vec())))
} else {
Ok(None)
}
}
pub fn read_range(
&self,
p: &F::P,
s: &Option<F::S>,
filter: &Option<F::Filter>,
limit: usize,
) -> Result<Vec<Arc<ByteBuf>>, Error> {
let partition_hash = p.hash();
let first_key = match s {
None => partition_hash.to_vec(),
Some(sk) => self.tree_key(p, sk),
};
let mut ret = vec![];
for item in self.store.range(first_key..) {
let (key, value) = item?;
if &key[..32] != partition_hash.as_slice() {
break;
}
let keep = match filter {
None => true,
Some(f) => {
let entry = self.decode_entry(value.as_ref())?;
F::matches_filter(&entry, f)
}
};
if keep {
ret.push(Arc::new(ByteBuf::from(value.as_ref())));
}
if ret.len() >= limit {
break;
}
}
Ok(ret)
}
// Mutation functions
// When changing this code, take care of propagating modifications correctly:
// - When an entry is modified or deleted, call the updated() function
// on the table instance
// - When an entry is modified or deleted, add it to the merkle updater's todo list.
// This has to be done atomically with the modification for the merkle updater
// to maintain consistency. The merkle updater must then be notified with todo_notify.
// - When an entry is updated to be a tombstone, add it to the gc_todo tree
pub(crate) fn update_many<T: Borrow<ByteBuf>>(&self, entries: &[T]) -> Result<(), Error> {
for update_bytes in entries.iter() {
self.update_entry(update_bytes.borrow().as_slice())?;
}
Ok(())
}
pub(crate) fn update_entry(&self, update_bytes: &[u8]) -> Result<(), Error> {
let update = self.decode_entry(update_bytes)?;
let tree_key = self.tree_key(update.partition_key(), update.sort_key());
let changed =
(&self.store, &self.merkle_updater.todo).transaction(|(store, mkl_todo)| {
let (old_entry, new_entry) = match store.get(&tree_key)? {
Some(prev_bytes) => {
let old_entry = self
.decode_entry(&prev_bytes)
.map_err(sled::transaction::ConflictableTransactionError::Abort)?;
let mut new_entry = old_entry.clone();
new_entry.merge(&update);
(Some(old_entry), new_entry)
}
None => (None, update.clone()),
};
if Some(&new_entry) != old_entry.as_ref() {
let new_bytes = rmp_to_vec_all_named(&new_entry)
.map_err(Error::RMPEncode)
.map_err(sled::transaction::ConflictableTransactionError::Abort)?;
let new_bytes_hash = blake2sum(&new_bytes[..]);
mkl_todo.insert(tree_key.clone(), new_bytes_hash.as_slice())?;
store.insert(tree_key.clone(), new_bytes)?;
Ok(Some((old_entry, new_entry, new_bytes_hash)))
} else {
Ok(None)
}
})?;
if let Some((old_entry, new_entry, new_bytes_hash)) = changed {
let is_tombstone = new_entry.is_tombstone();
self.instance.updated(old_entry, Some(new_entry));
self.merkle_updater.todo_notify.notify();
if is_tombstone {
self.gc_todo.insert(&tree_key, new_bytes_hash.as_slice())?;
}
}
Ok(())
}
pub(crate) fn delete_if_equal(self: &Arc<Self>, k: &[u8], v: &[u8]) -> Result<bool, Error> {
let removed =
(&self.store, &self.merkle_updater.todo).transaction(|(store, mkl_todo)| {
if let Some(cur_v) = store.get(k)? {
if cur_v == v {
store.remove(k)?;
mkl_todo.insert(k, vec![])?;
return Ok(true);
}
}
Ok(false)
})?;
if removed {
let old_entry = self.decode_entry(v)?;
self.instance.updated(Some(old_entry), None);
self.merkle_updater.todo_notify.notify();
}
Ok(removed)
}
pub(crate) fn delete_if_equal_hash(
self: &Arc<Self>,
k: &[u8],
vhash: Hash,
) -> Result<bool, Error> {
let removed =
(&self.store, &self.merkle_updater.todo).transaction(|(store, mkl_todo)| {
if let Some(cur_v) = store.get(k)? {
if blake2sum(&cur_v[..]) == vhash {
store.remove(k)?;
mkl_todo.insert(k, vec![])?;
return Ok(Some(cur_v));
}
}
Ok(None)
})?;
if let Some(old_v) = removed {
let old_entry = self.decode_entry(&old_v[..])?;
self.instance.updated(Some(old_entry), None);
self.merkle_updater.todo_notify.notify();
Ok(true)
} else {
Ok(false)
}
}
// ---- Utility functions ----
pub(crate) fn tree_key(&self, p: &F::P, s: &F::S) -> Vec<u8> {
let mut ret = p.hash().to_vec();
ret.extend(s.sort_key());
ret
}
pub(crate) fn decode_entry(&self, bytes: &[u8]) -> Result<F::E, Error> {
match rmp_serde::decode::from_read_ref::<_, F::E>(bytes) {
Ok(x) => Ok(x),
Err(e) => match F::try_migrate(bytes) {
Some(x) => Ok(x),
None => {
warn!("Unable to decode entry of {}: {}", self.name, e);
for line in hexdump::hexdump_iter(bytes) {
debug!("{}", line);
}
Err(e.into())
}
},
}
}
}
