312 lines
6.3 KiB
Rust
312 lines
6.3 KiB
Rust
use std::{
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collections::{
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HashMap,
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},
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iter::FromIterator,
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sync::{
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Mutex,
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MutexGuard,
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PoisonError,
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},
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};
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pub struct Store {
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status_dirs: HashMap <Vec <u8>, StatusKeyDirectory>,
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}
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#[derive (thiserror::Error, Debug, PartialEq)]
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pub enum Error {
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#[error ("key too long")]
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KeyTooLong,
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#[error ("mutex poisoned")]
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MutexPoisoned,
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#[error ("no such key dir")]
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NoSuchKeyDir,
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#[error ("value too long")]
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ValueTooLong,
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}
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pub struct StatusQuotas {
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pub max_keys: usize,
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pub max_key_bytes: usize,
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pub max_value_bytes: usize,
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pub max_payload_bytes: usize,
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}
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pub struct GetAfter {
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pub tuples: Vec <(Vec <u8>, Vec <u8>)>,
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pub sequence: u64,
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}
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impl Store {
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pub fn new <I> (status_dirs: I)
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-> Self
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where I: Iterator <Item = (Vec <u8>, StatusQuotas)>
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{
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let status_dirs = HashMap::from_iter (
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status_dirs
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.map (|(name, quotas)| (name, StatusKeyDirectory::new (quotas)))
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);
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Self {
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status_dirs,
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}
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}
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pub fn list_key_dirs (&self) -> Vec <Vec <u8>> {
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self.status_dirs.iter ()
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.map (|(k, _)| k.clone ())
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.collect ()
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}
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pub fn set (&self, name: &[u8], key: Vec <u8>, value: Vec <u8>)
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-> Result <(), Error>
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{
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let dir = self.status_dirs.get (name)
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.ok_or (Error::NoSuchKeyDir)?;
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dir.set (key, value)
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}
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pub fn get_after (&self, name: &[u8], thresh: Option <u64>)
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-> Result <GetAfter, Error>
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{
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let dir = self.status_dirs.get (name)
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.ok_or (Error::NoSuchKeyDir)?;
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dir.get_after (thresh)
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}
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}
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// End of public interface
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impl <T> From <PoisonError <MutexGuard <'_, T>>> for Error {
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fn from (_: PoisonError <MutexGuard <'_, T>>) -> Self {
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Self::MutexPoisoned
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}
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}
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enum StoreCommand {
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SetStatus (SetStatusCommand),
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Multi (Vec <StoreCommand>),
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}
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struct StatusKeyDirectory {
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quotas: StatusQuotas,
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// TODO: Make this tokio::sync::Mutex.
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table: Mutex <StatusTable>,
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}
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#[derive (Default)]
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struct StatusTable {
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map: HashMap <Vec <u8>, StatusValue>,
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sequence: u64,
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}
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struct StatusValue {
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value: Vec <u8>,
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sequence: u64,
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}
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struct SetStatusCommand {
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key_dir: Vec <u8>,
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key: Vec <u8>,
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value: Vec <u8>,
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}
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impl StatusKeyDirectory {
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fn new (quotas: StatusQuotas) -> Self {
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Self {
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quotas,
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table: Mutex::new (Default::default ()),
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}
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}
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fn set (&self, key: Vec <u8>, value: Vec <u8>) -> Result <(), Error>
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{
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if key.len () > self.quotas.max_key_bytes {
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return Err (Error::KeyTooLong);
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}
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if value.len () > self.quotas.max_value_bytes {
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return Err (Error::ValueTooLong);
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}
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{
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let mut guard = self.table.lock ()?;
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guard.set (&self.quotas, key, value);
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}
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Ok (())
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}
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fn get_after (&self, thresh: Option <u64>) -> Result <GetAfter, Error> {
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let guard = self.table.lock ()?;
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Ok (guard.get_after (thresh))
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}
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}
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impl StatusTable {
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fn payload_bytes (&self) -> usize {
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self.map.iter ()
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.map (|(k, v)| k.len () + v.len ())
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.sum ()
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}
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fn set (&mut self, quotas: &StatusQuotas, key: Vec <u8>, value: Vec <u8>) {
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self.sequence += 1;
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if self.map.len () > quotas.max_keys {
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self.map.clear ();
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}
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let new_bytes = key.len () + value.len ();
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if self.payload_bytes () + new_bytes > quotas.max_payload_bytes {
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self.map.clear ();
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}
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let value = StatusValue {
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value,
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sequence: self.sequence,
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};
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self.map.insert (key, value);
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}
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fn get_after (&self, thresh: Option <u64>) -> GetAfter {
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let thresh = thresh.unwrap_or (0);
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let tuples = self.map.iter ()
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.filter_map (|(key, value)| {
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if value.sequence <= thresh {
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return None;
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}
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Some ((key.clone (), value.value.clone ()))
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})
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.collect ();
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GetAfter {
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tuples,
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sequence: self.sequence,
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}
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}
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}
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impl StatusValue {
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fn len (&self) -> usize {
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self.value.len ()
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}
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}
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fn main () {
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println! ("Hello, world!");
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}
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#[cfg (test)]
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mod tests {
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use super::*;
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fn get_after_eq (a: &GetAfter, b: &GetAfter) {
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assert_eq! (a.sequence, b.sequence);
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let a = a.tuples.clone ();
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let b = b.tuples.clone ();
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let a = HashMap::<Vec <u8>, Vec <u8>>::from_iter (a.into_iter ());
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let b = HashMap::from_iter (b.into_iter ());
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assert_eq! (a, b);
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}
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#[test]
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fn store () {
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let s = Store::new (vec! [
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(b"key_dir".to_vec (), StatusQuotas {
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max_keys: 4,
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max_key_bytes: 16,
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max_value_bytes: 16,
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max_payload_bytes: 128,
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}),
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].into_iter ());
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let mut expected_sequence = 0;
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assert_eq! (s.list_key_dirs (), vec! [
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b"key_dir".to_vec (),
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]);
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assert_eq! (
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s.set (b"key_dir", b"this key is too long and will cause an error".to_vec (), b"bar".to_vec ()),
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Err (Error::KeyTooLong)
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);
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assert_eq! (
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s.set (b"key_dir", b"foo".to_vec (), b"this value is too long and will cause an error".to_vec ()),
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Err (Error::ValueTooLong)
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);
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assert_eq! (
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s.set (b"invalid_key_dir", b"foo".to_vec (), b"bar".to_vec ()),
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Err (Error::NoSuchKeyDir)
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);
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let ga = s.get_after (b"key_dir", None).unwrap ();
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assert_eq! (ga.sequence, expected_sequence);
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assert_eq! (ga.tuples, vec! []);
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s.set (b"key_dir", b"foo_1".to_vec (), b"bar_1".to_vec ()).unwrap ();
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expected_sequence += 1;
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let ga = s.get_after (b"key_dir", None).unwrap ();
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assert_eq! (ga.sequence, expected_sequence);
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assert_eq! (ga.tuples, vec! [
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(b"foo_1".to_vec (), b"bar_1".to_vec ()),
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]);
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get_after_eq (&ga, &GetAfter {
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sequence: expected_sequence,
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tuples: vec! [
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(b"foo_1".to_vec (), b"bar_1".to_vec ()),
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]
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});
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s.set (b"key_dir", b"foo_2".to_vec (), b"bar_2".to_vec ()).unwrap ();
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expected_sequence += 1;
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let ga = s.get_after (b"key_dir", None).unwrap ();
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get_after_eq (&ga, &GetAfter {
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sequence: expected_sequence,
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tuples: vec! [
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(b"foo_1".to_vec (), b"bar_1".to_vec ()),
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(b"foo_2".to_vec (), b"bar_2".to_vec ()),
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]
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});
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s.set (b"key_dir", b"foo_1".to_vec (), b"bar_3".to_vec ()).unwrap ();
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expected_sequence += 1;
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let ga = s.get_after (b"key_dir", None).unwrap ();
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get_after_eq (&ga, &GetAfter {
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sequence: expected_sequence,
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tuples: vec! [
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(b"foo_1".to_vec (), b"bar_3".to_vec ()),
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(b"foo_2".to_vec (), b"bar_2".to_vec ()),
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]
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});
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let ga = s.get_after (b"key_dir", Some (2)).unwrap ();
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get_after_eq (&ga, &GetAfter {
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sequence: expected_sequence,
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tuples: vec! [
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(b"foo_1".to_vec (), b"bar_3".to_vec ()),
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]
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});
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let ga = s.get_after (b"key_dir", Some (3)).unwrap ();
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get_after_eq (&ga, &GetAfter {
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sequence: expected_sequence,
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tuples: vec! []
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});
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}
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}
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