use std::collections::BTreeMap;
use std::ops::Bound::{self, Excluded, Included, Unbounded};
use std::sync::RwLock;
use sodiumoxide::{hex, crypto::hash};
use tokio::sync::Notify;
use crate::storage::*;
/// This implementation is very inneficient, and not completely correct
/// Indeed, when the connector is dropped, the memory is freed.
/// It means that when a user disconnects, its data are lost.
/// It's intended only for basic debugging, do not use it for advanced tests...
#[derive(Debug, Default)]
pub struct MemDb(tokio::sync::Mutex<HashMap<String, Arc<MemBuilder>>>);
impl MemDb {
pub fn new() -> Self {
Self(tokio::sync::Mutex::new(HashMap::new()))
}
pub async fn builder(&self, username: &str) -> Arc<MemBuilder> {
let mut global_storage = self.0.lock().await;
global_storage
.entry(username.to_string())
.or_insert(MemBuilder::new(username))
.clone()
}
}
#[derive(Debug, Clone)]
enum InternalData {
Tombstone,
Value(Vec<u8>),
}
impl InternalData {
fn to_alternative(&self) -> Alternative {
match self {
Self::Tombstone => Alternative::Tombstone,
Self::Value(x) => Alternative::Value(x.clone()),
}
}
}
#[derive(Debug)]
struct InternalRowVal {
data: Vec<InternalData>,
version: u64,
change: Arc<Notify>,
}
impl std::default::Default for InternalRowVal {
fn default() -> Self {
Self {
data: vec![],
version: 1,
change: Arc::new(Notify::new()),
}
}
}
impl InternalRowVal {
fn concurrent_values(&self) -> Vec<Alternative> {
self.data.iter().map(InternalData::to_alternative).collect()
}
fn to_row_val(&self, row_ref: RowRef) -> RowVal {
RowVal {
row_ref: row_ref.with_causality(self.version.to_string()),
value: self.concurrent_values(),
}
}
}
#[derive(Debug, Default, Clone)]
struct InternalBlobVal {
data: Vec<u8>,
metadata: HashMap<String, String>,
}
impl InternalBlobVal {
fn to_blob_val(&self, bref: &BlobRef) -> BlobVal {
BlobVal {
blob_ref: bref.clone(),
meta: self.metadata.clone(),
value: self.data.clone(),
}
}
fn etag(&self) -> String {
let digest = hash::hash(self.data.as_ref());
let buff = digest.as_ref();
let hexstr = hex::encode(buff);
format!("\"{}\"", hexstr)
}
}
type ArcRow = Arc<RwLock<HashMap<String, BTreeMap<String, InternalRowVal>>>>;
type ArcBlob = Arc<RwLock<BTreeMap<String, InternalBlobVal>>>;
#[derive(Clone, Debug)]
pub struct MemBuilder {
unicity: Vec<u8>,
row: ArcRow,
blob: ArcBlob,
}
impl MemBuilder {
pub fn new(user: &str) -> Arc<Self> {
tracing::debug!("initialize membuilder for {}", user);
let mut unicity: Vec<u8> = vec![];
unicity.extend_from_slice(file!().as_bytes());
unicity.extend_from_slice(user.as_bytes());
Arc::new(Self {
unicity,
row: Arc::new(RwLock::new(HashMap::new())),
blob: Arc::new(RwLock::new(BTreeMap::new())),
})
}
}
#[async_trait]
impl IBuilder for MemBuilder {
async fn build(&self) -> Result<Store, StorageError> {
Ok(Box::new(MemStore {
row: self.row.clone(),
blob: self.blob.clone(),
}))
}
fn unique(&self) -> UnicityBuffer {
UnicityBuffer(self.unicity.clone())
}
}
pub struct MemStore {
row: ArcRow,
blob: ArcBlob,
}
fn prefix_last_bound(prefix: &str) -> Bound<String> {
let mut sort_end = prefix.to_string();
match sort_end.pop() {
None => Unbounded,
Some(ch) => {
let nc = char::from_u32(ch as u32 + 1).unwrap();
sort_end.push(nc);
Excluded(sort_end)
}
}
}
impl MemStore {
fn row_rm_single(&self, entry: &RowRef) -> Result<(), StorageError> {
tracing::trace!(entry=%entry, command="row_rm_single");
let mut store = self.row.write().or(Err(StorageError::Internal))?;
let shard = &entry.uid.shard;
let sort = &entry.uid.sort;
let cauz = match entry.causality.as_ref().map(|v| v.parse::<u64>()) {
Some(Ok(v)) => v,
_ => 0,
};
let bt = store.entry(shard.to_string()).or_default();
let intval = bt.entry(sort.to_string()).or_default();
if cauz == intval.version {
intval.data.clear();
}
intval.data.push(InternalData::Tombstone);
intval.version += 1;
intval.change.notify_waiters();
Ok(())
}
}
#[async_trait]
impl IStore for MemStore {
async fn row_fetch<'a>(&self, select: &Selector<'a>) -> Result<Vec<RowVal>, StorageError> {
tracing::trace!(select=%select, command="row_fetch");
let store = self.row.read().or(Err(StorageError::Internal))?;
match select {
Selector::Range {
shard,
sort_begin,
sort_end,
} => Ok(store
.get(*shard)
.unwrap_or(&BTreeMap::new())
.range((
Included(sort_begin.to_string()),
Excluded(sort_end.to_string()),
))
.map(|(k, v)| v.to_row_val(RowRef::new(shard, k)))
.collect::<Vec<_>>()),
Selector::List(rlist) => {
let mut acc = vec![];
for row_ref in rlist {
let maybe_intval = store
.get(&row_ref.uid.shard)
.map(|v| v.get(&row_ref.uid.sort))
.flatten();
if let Some(intval) = maybe_intval {
acc.push(intval.to_row_val(row_ref.clone()));
}
}
Ok(acc)
}
Selector::Prefix { shard, sort_prefix } => {
let last_bound = prefix_last_bound(sort_prefix);
Ok(store
.get(*shard)
.unwrap_or(&BTreeMap::new())
.range((Included(sort_prefix.to_string()), last_bound))
.map(|(k, v)| v.to_row_val(RowRef::new(shard, k)))
.collect::<Vec<_>>())
}
Selector::Single(row_ref) => {
let intval = store
.get(&row_ref.uid.shard)
.ok_or(StorageError::NotFound)?
.get(&row_ref.uid.sort)
.ok_or(StorageError::NotFound)?;
Ok(vec![intval.to_row_val((*row_ref).clone())])
}
}
}
async fn row_rm<'a>(&self, select: &Selector<'a>) -> Result<(), StorageError> {
tracing::trace!(select=%select, command="row_rm");
let values = match select {
Selector::Range { .. } | Selector::Prefix { .. } => self
.row_fetch(select)
.await?
.into_iter()
.map(|rv| rv.row_ref)
.collect::<Vec<_>>(),
Selector::List(rlist) => rlist.clone(),
Selector::Single(row_ref) => vec![(*row_ref).clone()],
};
for v in values.into_iter() {
self.row_rm_single(&v)?;
}
Ok(())
}
async fn row_insert(&self, values: Vec<RowVal>) -> Result<(), StorageError> {
tracing::trace!(entries=%values.iter().map(|v| v.row_ref.to_string()).collect::<Vec<_>>().join(","), command="row_insert");
let mut store = self.row.write().or(Err(StorageError::Internal))?;
for v in values.into_iter() {
let shard = v.row_ref.uid.shard;
let sort = v.row_ref.uid.sort;
let val = match v.value.into_iter().next() {
Some(Alternative::Value(x)) => x,
_ => vec![],
};
let cauz = match v.row_ref.causality.map(|v| v.parse::<u64>()) {
Some(Ok(v)) => v,
_ => 0,
};
let bt = store.entry(shard).or_default();
let intval = bt.entry(sort).or_default();
if cauz == intval.version {
intval.data.clear();
}
intval.data.push(InternalData::Value(val));
intval.version += 1;
intval.change.notify_waiters();
}
Ok(())
}
async fn row_poll(&self, value: &RowRef) -> Result<RowVal, StorageError> {
tracing::trace!(entry=%value, command="row_poll");
let shard = &value.uid.shard;
let sort = &value.uid.sort;
let cauz = match value.causality.as_ref().map(|v| v.parse::<u64>()) {
Some(Ok(v)) => v,
_ => 0,
};
let notify_me = {
let mut store = self.row.write().or(Err(StorageError::Internal))?;
let bt = store.entry(shard.to_string()).or_default();
let intval = bt.entry(sort.to_string()).or_default();
if intval.version != cauz {
return Ok(intval.to_row_val(value.clone()));
}
intval.change.clone()
};
notify_me.notified().await;
let res = self.row_fetch(&Selector::Single(value)).await?;
res.into_iter().next().ok_or(StorageError::NotFound)
}
async fn blob_fetch(&self, blob_ref: &BlobRef) -> Result<BlobVal, StorageError> {
tracing::trace!(entry=%blob_ref, command="blob_fetch");
let store = self.blob.read().or(Err(StorageError::Internal))?;
store
.get(&blob_ref.0)
.ok_or(StorageError::NotFound)
.map(|v| v.to_blob_val(blob_ref))
}
async fn blob_insert(&self, blob_val: BlobVal) -> Result<String, StorageError> {
tracing::trace!(entry=%blob_val.blob_ref, command="blob_insert");
let mut store = self.blob.write().or(Err(StorageError::Internal))?;
let entry = store.entry(blob_val.blob_ref.0.clone()).or_default();
entry.data = blob_val.value.clone();
entry.metadata = blob_val.meta.clone();
Ok(entry.etag())
}
async fn blob_copy(&self, src: &BlobRef, dst: &BlobRef) -> Result<(), StorageError> {
tracing::trace!(src=%src, dst=%dst, command="blob_copy");
let mut store = self.blob.write().or(Err(StorageError::Internal))?;
let blob_src = store.entry(src.0.clone()).or_default().clone();
store.insert(dst.0.clone(), blob_src);
Ok(())
}
async fn blob_list(&self, prefix: &str) -> Result<Vec<BlobRef>, StorageError> {
tracing::trace!(prefix = prefix, command = "blob_list");
let store = self.blob.read().or(Err(StorageError::Internal))?;
let last_bound = prefix_last_bound(prefix);
let blist = store
.range((Included(prefix.to_string()), last_bound))
.map(|(k, _)| BlobRef(k.to_string()))
.collect::<Vec<_>>();
Ok(blist)
}
async fn blob_rm(&self, blob_ref: &BlobRef) -> Result<(), StorageError> {
tracing::trace!(entry=%blob_ref, command="blob_rm");
let mut store = self.blob.write().or(Err(StorageError::Internal))?;
store.remove(&blob_ref.0);
Ok(())
}
}