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1422 1423 1424 1425 1426 1427
use super::{
value_initializer::{InitResult, ValueInitializer},
ConcurrentCacheExt,
};
use crate::{
sync::{
base_cache::{BaseCache, HouseKeeperArc, MAX_SYNC_REPEATS, WRITE_RETRY_INTERVAL_MICROS},
housekeeper::InnerSync,
PredicateId, WriteOp,
},
PredicateError,
};
use crossbeam_channel::{Sender, TrySendError};
use std::{
any::TypeId,
borrow::Borrow,
collections::hash_map::RandomState,
future::Future,
hash::{BuildHasher, Hash},
sync::Arc,
time::Duration,
};
/// A thread-safe, futures-aware concurrent in-memory cache.
///
/// `Cache` supports full concurrency of retrievals and a high expected concurrency
/// for updates. It can be accessed inside and outside of asynchronous contexts.
///
/// `Cache` utilizes a lock-free concurrent hash table `SegmentedHashMap` from the
/// [moka-cht][moka-cht-crate] crate for the central key-value storage. `Cache`
/// performs a best-effort bounding of the map using an entry replacement algorithm
/// to determine which entries to evict when the capacity is exceeded.
///
/// To use this cache, enable a crate feature called "future".
///
/// [moka-cht-crate]: https://crates.io/crates/moka-cht
///
/// # Examples
///
/// Cache entries are manually added using an insert method, and are stored in the
/// cache until either evicted or manually invalidated:
///
/// - Inside an async context (`async fn` or `async` block), use
/// [`insert`](#method.insert) or [`invalidate`](#method.invalidate) method for
/// updating the cache and `await` them.
/// - Outside any async context, use [`blocking_insert`](#method.blocking_insert) or
/// [`blocking_invalidate`](#method.blocking_invalidate) methods. They will block
/// for a short time under heavy updates.
///
/// Here's an example of reading and updating a cache by using multiple asynchronous
/// tasks with [Tokio][tokio-crate] runtime:
///
/// [tokio-crate]: https://crates.io/crates/tokio
///
///```rust
/// // Cargo.toml
/// //
/// // [dependencies]
/// // moka = { version = "0.6", features = ["future"] }
/// // tokio = { version = "1", features = ["rt-multi-thread", "macros" ] }
/// // futures = "0.3"
///
/// use moka::future::Cache;
///
/// #[tokio::main]
/// async fn main() {
/// const NUM_TASKS: usize = 16;
/// const NUM_KEYS_PER_TASK: usize = 64;
///
/// fn value(n: usize) -> String {
/// format!("value {}", n)
/// }
///
/// // Create a cache that can store up to 10,000 entries.
/// let cache = Cache::new(10_000);
///
/// // Spawn async tasks and write to and read from the cache.
/// let tasks: Vec<_> = (0..NUM_TASKS)
/// .map(|i| {
/// // To share the same cache across the async tasks, clone it.
/// // This is a cheap operation.
/// let my_cache = cache.clone();
/// let start = i * NUM_KEYS_PER_TASK;
/// let end = (i + 1) * NUM_KEYS_PER_TASK;
///
/// tokio::spawn(async move {
/// // Insert 64 entries. (NUM_KEYS_PER_TASK = 64)
/// for key in start..end {
/// // insert() is an async method, so await it.
/// my_cache.insert(key, value(key)).await;
/// // get() returns Option<String>, a clone of the stored value.
/// assert_eq!(my_cache.get(&key), Some(value(key)));
/// }
///
/// // Invalidate every 4 element of the inserted entries.
/// for key in (start..end).step_by(4) {
/// // invalidate() is an async method, so await it.
/// my_cache.invalidate(&key).await;
/// }
/// })
/// })
/// .collect();
///
/// // Wait for all tasks to complete.
/// futures_util::future::join_all(tasks).await;
///
/// // Verify the result.
/// for key in 0..(NUM_TASKS * NUM_KEYS_PER_TASK) {
/// if key % 4 == 0 {
/// assert_eq!(cache.get(&key), None);
/// } else {
/// assert_eq!(cache.get(&key), Some(value(key)));
/// }
/// }
/// }
/// ```
///
/// # Thread Safety
///
/// All methods provided by the `Cache` are considered thread-safe, and can be safely
/// accessed by multiple concurrent threads.
///
/// - `Cache<K, V, S>` requires trait bounds `Send`, `Sync` and `'static` for `K`
/// (key), `V` (value) and `S` (hasher state).
/// - `Cache<K, V, S>` will implement `Send` and `Sync`.
///
/// # Sharing a cache across asynchronous tasks
///
/// To share a cache across async tasks (or OS threads), do one of the followings:
///
/// - Create a clone of the cache by calling its `clone` method and pass it to other
/// task.
/// - Wrap the cache by a `sync::OnceCell` or `sync::Lazy` from
/// [once_cell][once-cell-crate] create, and set it to a `static` variable.
///
/// Cloning is a cheap operation for `Cache` as it only creates thread-safe
/// reference-counted pointers to the internal data structures.
///
/// [once-cell-crate]: https://crates.io/crates/once_cell
///
/// # Avoiding to clone the value at `get`
///
/// The return type of `get` method is `Option<V>` instead of `Option<&V>`. Every
/// time `get` is called for an existing key, it creates a clone of the stored value
/// `V` and returns it. This is because the `Cache` allows concurrent updates from
/// threads so a value stored in the cache can be dropped or replaced at any time by
/// any other thread. `get` cannot return a reference `&V` as it is impossible to
/// guarantee the value outlives the reference.
///
/// If you want to store values that will be expensive to clone, wrap them by
/// `std::sync::Arc` before storing in a cache. [`Arc`][rustdoc-std-arc] is a
/// thread-safe reference-counted pointer and its `clone()` method is cheap.
///
/// [rustdoc-std-arc]: https://doc.rust-lang.org/stable/std/sync/struct.Arc.html
///
/// # Expiration Policies
///
/// `Cache` supports the following expiration policies:
///
/// - **Time to live**: A cached entry will be expired after the specified duration
/// past from `insert`.
/// - **Time to idle**: A cached entry will be expired after the specified duration
/// past from `get` or `insert`.
///
/// See the [`CacheBuilder`][builder-struct]'s doc for how to configure a cache
/// with them.
///
/// [builder-struct]: ./struct.CacheBuilder.html
///
/// # Hashing Algorithm
///
/// By default, `Cache` uses a hashing algorithm selected to provide resistance
/// against HashDoS attacks. It will be the same one used by
/// `std::collections::HashMap`, which is currently SipHash 1-3.
///
/// While SipHash's performance is very competitive for medium sized keys, other
/// hashing algorithms will outperform it for small keys such as integers as well as
/// large keys such as long strings. However those algorithms will typically not
/// protect against attacks such as HashDoS.
///
/// The hashing algorithm can be replaced on a per-`Cache` basis using the
/// [`build_with_hasher`][build-with-hasher-method] method of the
/// `CacheBuilder`. Many alternative algorithms are available on crates.io, such
/// as the [aHash][ahash-crate] crate.
///
/// [build-with-hasher-method]: ./struct.CacheBuilder.html#method.build_with_hasher
/// [ahash-crate]: https://crates.io/crates/ahash
///
#[derive(Clone)]
pub struct Cache<K, V, S = RandomState> {
base: BaseCache<K, V, S>,
value_initializer: Arc<ValueInitializer<K, V, S>>,
}
// TODO: https://github.com/moka-rs/moka/issues/54
#[allow(clippy::non_send_fields_in_send_ty)]
unsafe impl<K, V, S> Send for Cache<K, V, S>
where
K: Send + Sync,
V: Send + Sync,
S: Send,
{
}
unsafe impl<K, V, S> Sync for Cache<K, V, S>
where
K: Send + Sync,
V: Send + Sync,
S: Sync,
{
}
impl<K, V> Cache<K, V, RandomState>
where
K: Hash + Eq + Send + Sync + 'static,
V: Clone + Send + Sync + 'static,
{
/// Constructs a new `Cache<K, V>` that will store up to the `max_capacity` entries.
///
/// To adjust various configuration knobs such as `initial_capacity` or
/// `time_to_live`, use the [`CacheBuilder`][builder-struct].
///
/// [builder-struct]: ./struct.CacheBuilder.html
pub fn new(max_capacity: usize) -> Self {
let build_hasher = RandomState::default();
Self::with_everything(max_capacity, None, build_hasher, None, None, false)
}
}
impl<K, V, S> Cache<K, V, S>
where
K: Hash + Eq + Send + Sync + 'static,
V: Clone + Send + Sync + 'static,
S: BuildHasher + Clone + Send + Sync + 'static,
{
pub(crate) fn with_everything(
max_capacity: usize,
initial_capacity: Option<usize>,
build_hasher: S,
time_to_live: Option<Duration>,
time_to_idle: Option<Duration>,
invalidator_enabled: bool,
) -> Self {
Self {
base: BaseCache::new(
max_capacity,
initial_capacity,
build_hasher.clone(),
time_to_live,
time_to_idle,
invalidator_enabled,
),
value_initializer: Arc::new(ValueInitializer::with_hasher(build_hasher)),
}
}
/// Returns a _clone_ of the value corresponding to the key.
///
/// If you want to store values that will be expensive to clone, wrap them by
/// `std::sync::Arc` before storing in a cache. [`Arc`][rustdoc-std-arc] is a
/// thread-safe reference-counted pointer and its `clone()` method is cheap.
///
/// The key may be any borrowed form of the cache's key type, but `Hash` and `Eq`
/// on the borrowed form _must_ match those for the key type.
///
/// [rustdoc-std-arc]: https://doc.rust-lang.org/stable/std/sync/struct.Arc.html
pub fn get<Q>(&self, key: &Q) -> Option<V>
where
Arc<K>: Borrow<Q>,
Q: Hash + Eq + ?Sized,
{
self.base.get_with_hash(key, self.base.hash(key))
}
/// Ensures the value of the key exists by inserting the output of the init
/// future if not exist, and returns a _clone_ of the value.
///
/// This method prevents to resolve the init future multiple times on the same
/// key even if the method is concurrently called by many async tasks; only one
/// of the calls resolves its future, and other calls wait for that future to
/// complete.
///
/// # Example
///
/// ```rust
/// // Cargo.toml
/// //
/// // [dependencies]
/// // moka = { version = "0.6", features = ["future"] }
/// // futures = "0.3"
/// // tokio = { version = "1", features = ["rt-multi-thread", "macros" ] }
/// use moka::future::Cache;
/// use std::sync::Arc;
///
/// #[tokio::main]
/// async fn main() {
/// const TEN_MIB: usize = 10 * 1024 * 1024; // 10MiB
/// let cache = Cache::new(100);
///
/// // Spawn four async tasks.
/// let tasks: Vec<_> = (0..4_u8)
/// .map(|task_id| {
/// let my_cache = cache.clone();
/// tokio::spawn(async move {
/// println!("Task {} started.", task_id);
///
/// // Insert and get the value for key1. Although all four async tasks
/// // will call `get_or_insert_with` at the same time, the `init` async
/// // block must be resolved only once.
/// let value = my_cache
/// .get_or_insert_with("key1", async move {
/// println!("Task {} inserting a value.", task_id);
/// Arc::new(vec![0u8; TEN_MIB])
/// })
/// .await;
///
/// // Ensure the value exists now.
/// assert_eq!(value.len(), TEN_MIB);
/// assert!(my_cache.get(&"key1").is_some());
///
/// println!("Task {} got the value. (len: {})", task_id, value.len());
/// })
/// })
/// .collect();
///
/// // Run all tasks concurrently and wait for them to complete.
/// futures_util::future::join_all(tasks).await;
/// }
/// ```
///
/// **A Sample Result**
///
/// - The `init` future (async black) was resolved exactly once by task 3.
/// - Other tasks were blocked until task 3 inserted the value.
///
/// ```console
/// Task 0 started.
/// Task 3 started.
/// Task 1 started.
/// Task 2 started.
/// Task 3 inserting a value.
/// Task 3 got the value. (len: 10485760)
/// Task 0 got the value. (len: 10485760)
/// Task 1 got the value. (len: 10485760)
/// Task 2 got the value. (len: 10485760)
/// ```
///
/// # Panics
///
/// This method panics when the `init` future has been panicked. When it happens,
/// only the caller whose `init` future panicked will get the panic (e.g. only
/// task 3 in the above sample). If there are other calls in progress (e.g. task
/// 0, 1 and 2 above), this method will restart and resolve one of the remaining
/// `init` futures.
///
pub async fn get_or_insert_with<F>(&self, key: K, init: F) -> V
where
F: Future<Output = V>,
{
let hash = self.base.hash(&key);
let key = Arc::new(key);
self.get_or_insert_with_hash_and_fun(key, hash, init).await
}
/// Try to ensure the value of the key exists by inserting an `Ok` output of the
/// init future if not exist, and returns a _clone_ of the value or the `Err`
/// produced by the future.
///
/// This method prevents to resolve the init future multiple times on the same
/// key even if the method is concurrently called by many async tasks; only one
/// of the calls resolves its future (as long as these futures return the same
/// error type), and other calls wait for that future to complete.
///
/// # Example
///
/// ```rust
/// // Cargo.toml
/// //
/// // [dependencies]
/// // moka = { version = "0.6", features = ["future"] }
/// // futures = "0.3"
/// // reqwest = "0.11"
/// // tokio = { version = "1", features = ["rt-multi-thread", "macros" ] }
/// use moka::future::Cache;
///
/// // This async function tries to get HTML from the given URI.
/// async fn get_html(task_id: u8, uri: &str) -> Result<String, reqwest::Error> {
/// println!("get_html() called by task {}.", task_id);
/// Ok(reqwest::get(uri).await?.text().await?)
/// }
///
/// #[tokio::main]
/// async fn main() {
/// let cache = Cache::new(100);
///
/// // Spawn four async tasks.
/// let tasks: Vec<_> = (0..4_u8)
/// .map(|task_id| {
/// let my_cache = cache.clone();
/// tokio::spawn(async move {
/// println!("Task {} started.", task_id);
///
/// // Try to insert and get the value for key1. Although
/// // all four async tasks will call `get_or_try_insert_with`
/// // at the same time, get_html() must be called only once.
/// let value = my_cache
/// .get_or_try_insert_with(
/// "key1",
/// get_html(task_id, "https://www.rust-lang.org"),
/// ).await;
///
/// // Ensure the value exists now.
/// assert!(value.is_ok());
/// assert!(my_cache.get(&"key1").is_some());
///
/// println!(
/// "Task {} got the value. (len: {})",
/// task_id,
/// value.unwrap().len()
/// );
/// })
/// })
/// .collect();
///
/// // Run all tasks concurrently and wait for them to complete.
/// futures_util::future::join_all(tasks).await;
/// }
/// ```
///
/// **A Sample Result**
///
/// - `get_html()` was called exactly once by task 2.
/// - Other tasks were blocked until task 2 inserted the value.
///
/// ```console
/// Task 1 started.
/// Task 0 started.
/// Task 2 started.
/// Task 3 started.
/// get_html() called by task 2.
/// Task 2 got the value. (len: 19419)
/// Task 1 got the value. (len: 19419)
/// Task 0 got the value. (len: 19419)
/// Task 3 got the value. (len: 19419)
/// ```
///
/// # Panics
///
/// This method panics when the `init` future has been panicked. When it happens,
/// only the caller whose `init` future panicked will get the panic (e.g. only
/// task 2 in the above sample). If there are other calls in progress (e.g. task
/// 0, 1 and 3 above), this method will restart and resolve one of the remaining
/// `init` futures.
///
pub async fn get_or_try_insert_with<F, E>(&self, key: K, init: F) -> Result<V, Arc<E>>
where
F: Future<Output = Result<V, E>>,
E: Send + Sync + 'static,
{
let hash = self.base.hash(&key);
let key = Arc::new(key);
self.get_or_try_insert_with_hash_and_fun(key, hash, init)
.await
}
/// Inserts a key-value pair into the cache.
///
/// If the cache has this key present, the value is updated.
pub async fn insert(&self, key: K, value: V) {
let hash = self.base.hash(&key);
let key = Arc::new(key);
self.insert_with_hash(key, hash, value).await
}
/// Blocking [insert](#method.insert) to call outside of asynchronous contexts.
///
/// This method is intended for use cases where you are inserting from
/// synchronous code.
pub fn blocking_insert(&self, key: K, value: V) {
let hash = self.base.hash(&key);
let key = Arc::new(key);
let op = self.base.do_insert_with_hash(key, hash, value);
let hk = self.base.housekeeper.as_ref();
Self::blocking_schedule_write_op(&self.base.write_op_ch, op, hk).expect("Failed to insert");
}
/// Discards any cached value for the key.
///
/// The key may be any borrowed form of the cache's key type, but `Hash` and `Eq`
/// on the borrowed form _must_ match those for the key type.
pub async fn invalidate<Q>(&self, key: &Q)
where
Arc<K>: Borrow<Q>,
Q: Hash + Eq + ?Sized,
{
if let Some(entry) = self.base.remove(key) {
let op = WriteOp::Remove(entry);
let hk = self.base.housekeeper.as_ref();
Self::schedule_write_op(&self.base.write_op_ch, op, hk)
.await
.expect("Failed to remove");
}
}
/// Blocking [invalidate](#method.invalidate) to call outside of asynchronous
/// contexts.
///
/// This method is intended for use cases where you are invalidating from
/// synchronous code.
pub fn blocking_invalidate<Q>(&self, key: &Q)
where
Arc<K>: Borrow<Q>,
Q: Hash + Eq + ?Sized,
{
if let Some(entry) = self.base.remove(key) {
let op = WriteOp::Remove(entry);
let hk = self.base.housekeeper.as_ref();
Self::blocking_schedule_write_op(&self.base.write_op_ch, op, hk)
.expect("Failed to remove");
}
}
/// Discards all cached values.
///
/// This method returns immediately and a background thread will evict all the
/// cached values inserted before the time when this method was called. It is
/// guaranteed that the `get` method must not return these invalidated values
/// even if they have not been evicted.
///
/// Like the `invalidate` method, this method does not clear the historic
/// popularity estimator of keys so that it retains the client activities of
/// trying to retrieve an item.
pub fn invalidate_all(&self) {
self.base.invalidate_all();
}
/// Discards cached values that satisfy a predicate.
///
/// `invalidate_entries_if` takes a closure that returns `true` or `false`. This
/// method returns immediately and a background thread will apply the closure to
/// each cached value inserted before the time when `invalidate_entries_if` was
/// called. If the closure returns `true` on a value, that value will be evicted
/// from the cache.
///
/// Also the `get` method will apply the closure to a value to determine if it
/// should have been invalidated. Therefore, it is guaranteed that the `get`
/// method must not return invalidated values.
///
/// Note that you must call
/// [`CacheBuilder::support_invalidation_closures`][support-invalidation-closures]
/// at the cache creation time as the cache needs to maintain additional internal
/// data structures to support this method. Otherwise, calling this method will
/// fail with a
/// [`PredicateError::InvalidationClosuresDisabled`][invalidation-disabled-error].
///
/// Like the `invalidate` method, this method does not clear the historic
/// popularity estimator of keys so that it retains the client activities of
/// trying to retrieve an item.
///
/// [support-invalidation-closures]: ./struct.CacheBuilder.html#method.support_invalidation_closures
/// [invalidation-disabled-error]: ../enum.PredicateError.html#variant.InvalidationClosuresDisabled
pub fn invalidate_entries_if<F>(&self, predicate: F) -> Result<PredicateId, PredicateError>
where
F: Fn(&K, &V) -> bool + Send + Sync + 'static,
{
self.base.invalidate_entries_if(Arc::new(predicate))
}
/// Returns the `max_capacity` of this cache.
pub fn max_capacity(&self) -> usize {
self.base.max_capacity()
}
/// Returns the `time_to_live` of this cache.
pub fn time_to_live(&self) -> Option<Duration> {
self.base.time_to_live()
}
/// Returns the `time_to_idle` of this cache.
pub fn time_to_idle(&self) -> Option<Duration> {
self.base.time_to_idle()
}
/// Returns the number of internal segments of this cache.
///
/// `Cache` always returns `1`.
pub fn num_segments(&self) -> usize {
1
}
}
impl<K, V, S> ConcurrentCacheExt<K, V> for Cache<K, V, S>
where
K: Hash + Eq + Send + Sync + 'static,
V: Send + Sync + 'static,
S: BuildHasher + Clone + Send + Sync + 'static,
{
fn sync(&self) {
self.base.inner.sync(MAX_SYNC_REPEATS);
}
}
// private methods
impl<K, V, S> Cache<K, V, S>
where
K: Hash + Eq + Send + Sync + 'static,
V: Clone + Send + Sync + 'static,
S: BuildHasher + Clone + Send + Sync + 'static,
{
async fn get_or_insert_with_hash_and_fun(
&self,
key: Arc<K>,
hash: u64,
init: impl Future<Output = V>,
) -> V {
if let Some(v) = self.base.get_with_hash(&key, hash) {
return v;
}
match self
.value_initializer
.init_or_read(Arc::clone(&key), init)
.await
{
InitResult::Initialized(v) => {
self.insert_with_hash(Arc::clone(&key), hash, v.clone())
.await;
self.value_initializer
.remove_waiter(&key, TypeId::of::<()>());
v
}
InitResult::ReadExisting(v) => v,
InitResult::InitErr(_) => unreachable!(),
}
}
async fn get_or_try_insert_with_hash_and_fun<F, E>(
&self,
key: Arc<K>,
hash: u64,
init: F,
) -> Result<V, Arc<E>>
where
F: Future<Output = Result<V, E>>,
E: Send + Sync + 'static,
{
if let Some(v) = self.base.get_with_hash(&key, hash) {
return Ok(v);
}
match self
.value_initializer
.try_init_or_read(Arc::clone(&key), init)
.await
{
InitResult::Initialized(v) => {
let hash = self.base.hash(&key);
self.insert_with_hash(Arc::clone(&key), hash, v.clone())
.await;
self.value_initializer
.remove_waiter(&key, TypeId::of::<E>());
Ok(v)
}
InitResult::ReadExisting(v) => Ok(v),
InitResult::InitErr(e) => Err(e),
}
}
async fn insert_with_hash(&self, key: Arc<K>, hash: u64, value: V) {
let op = self.base.do_insert_with_hash(key, hash, value);
let hk = self.base.housekeeper.as_ref();
Self::schedule_write_op(&self.base.write_op_ch, op, hk)
.await
.expect("Failed to insert");
}
#[inline]
async fn schedule_write_op(
ch: &Sender<WriteOp<K, V>>,
op: WriteOp<K, V>,
housekeeper: Option<&HouseKeeperArc<K, V, S>>,
) -> Result<(), TrySendError<WriteOp<K, V>>> {
let mut op = op;
// TODO: Try to replace the timer with an async event listener to see if it
// can provide better performance.
loop {
BaseCache::apply_reads_writes_if_needed(ch, housekeeper);
match ch.try_send(op) {
Ok(()) => break,
Err(TrySendError::Full(op1)) => {
op = op1;
async_io::Timer::after(Duration::from_micros(WRITE_RETRY_INTERVAL_MICROS))
.await;
}
Err(e @ TrySendError::Disconnected(_)) => return Err(e),
}
}
Ok(())
}
#[inline]
fn blocking_schedule_write_op(
ch: &Sender<WriteOp<K, V>>,
op: WriteOp<K, V>,
housekeeper: Option<&HouseKeeperArc<K, V, S>>,
) -> Result<(), TrySendError<WriteOp<K, V>>> {
let mut op = op;
loop {
BaseCache::apply_reads_writes_if_needed(ch, housekeeper);
match ch.try_send(op) {
Ok(()) => break,
Err(TrySendError::Full(op1)) => {
op = op1;
std::thread::sleep(Duration::from_micros(WRITE_RETRY_INTERVAL_MICROS));
}
Err(e @ TrySendError::Disconnected(_)) => return Err(e),
}
}
Ok(())
}
}
// For unit tests.
#[cfg(test)]
impl<K, V, S> Cache<K, V, S>
where
K: Hash + Eq + Send + Sync + 'static,
V: Send + Sync + 'static,
S: BuildHasher + Clone + Send + Sync + 'static,
{
fn is_table_empty(&self) -> bool {
self.table_size() == 0
}
fn table_size(&self) -> usize {
self.base.table_size()
}
fn invalidation_predicate_count(&self) -> usize {
self.base.invalidation_predicate_count()
}
fn reconfigure_for_testing(&mut self) {
self.base.reconfigure_for_testing();
}
fn set_expiration_clock(&self, clock: Option<crate::common::time::Clock>) {
self.base.set_expiration_clock(clock);
}
}
// To see the debug prints, run test as `cargo test -- --nocapture`
#[cfg(test)]
mod tests {
use super::{Cache, ConcurrentCacheExt};
use crate::{common::time::Clock, future::CacheBuilder};
use async_io::Timer;
use std::{convert::Infallible, sync::Arc, time::Duration};
#[tokio::test]
async fn basic_single_async_task() {
let mut cache = Cache::new(3);
cache.reconfigure_for_testing();
// Make the cache exterior immutable.
let cache = cache;
cache.insert("a", "alice").await;
cache.insert("b", "bob").await;
assert_eq!(cache.get(&"a"), Some("alice"));
assert_eq!(cache.get(&"b"), Some("bob"));
cache.sync();
// counts: a -> 1, b -> 1
cache.insert("c", "cindy").await;
assert_eq!(cache.get(&"c"), Some("cindy"));
// counts: a -> 1, b -> 1, c -> 1
cache.sync();
assert_eq!(cache.get(&"a"), Some("alice"));
assert_eq!(cache.get(&"b"), Some("bob"));
cache.sync();
// counts: a -> 2, b -> 2, c -> 1
// "d" should not be admitted because its frequency is too low.
cache.insert("d", "david").await; // count: d -> 0
cache.sync();
assert_eq!(cache.get(&"d"), None); // d -> 1
cache.insert("d", "david").await;
cache.sync();
assert_eq!(cache.get(&"d"), None); // d -> 2
// "d" should be admitted and "c" should be evicted
// because d's frequency is higher then c's.
cache.insert("d", "dennis").await;
cache.sync();
assert_eq!(cache.get(&"a"), Some("alice"));
assert_eq!(cache.get(&"b"), Some("bob"));
assert_eq!(cache.get(&"c"), None);
assert_eq!(cache.get(&"d"), Some("dennis"));
cache.invalidate(&"b").await;
assert_eq!(cache.get(&"b"), None);
}
#[test]
fn basic_single_blocking_api() {
let mut cache = Cache::new(3);
cache.reconfigure_for_testing();
// Make the cache exterior immutable.
let cache = cache;
cache.blocking_insert("a", "alice");
cache.blocking_insert("b", "bob");
assert_eq!(cache.get(&"a"), Some("alice"));
assert_eq!(cache.get(&"b"), Some("bob"));
cache.sync();
// counts: a -> 1, b -> 1
cache.blocking_insert("c", "cindy");
assert_eq!(cache.get(&"c"), Some("cindy"));
// counts: a -> 1, b -> 1, c -> 1
cache.sync();
assert_eq!(cache.get(&"a"), Some("alice"));
assert_eq!(cache.get(&"b"), Some("bob"));
cache.sync();
// counts: a -> 2, b -> 2, c -> 1
// "d" should not be admitted because its frequency is too low.
cache.blocking_insert("d", "david"); // count: d -> 0
cache.sync();
assert_eq!(cache.get(&"d"), None); // d -> 1
cache.blocking_insert("d", "david");
cache.sync();
assert_eq!(cache.get(&"d"), None); // d -> 2
// "d" should be admitted and "c" should be evicted
// because d's frequency is higher then c's.
cache.blocking_insert("d", "dennis");
cache.sync();
assert_eq!(cache.get(&"a"), Some("alice"));
assert_eq!(cache.get(&"b"), Some("bob"));
assert_eq!(cache.get(&"c"), None);
assert_eq!(cache.get(&"d"), Some("dennis"));
cache.blocking_invalidate(&"b");
assert_eq!(cache.get(&"b"), None);
}
#[tokio::test]
async fn basic_multi_async_tasks() {
let num_threads = 4;
let cache = Cache::new(100);
let tasks = (0..num_threads)
.map(|id| {
let cache = cache.clone();
if id == 0 {
tokio::spawn(async move {
cache.blocking_insert(10, format!("{}-100", id));
cache.get(&10);
cache.blocking_insert(20, format!("{}-200", id));
cache.blocking_invalidate(&10);
})
} else {
tokio::spawn(async move {
cache.insert(10, format!("{}-100", id)).await;
cache.get(&10);
cache.insert(20, format!("{}-200", id)).await;
cache.invalidate(&10).await;
})
}
})
.collect::<Vec<_>>();
let _ = futures_util::future::join_all(tasks).await;
assert!(cache.get(&10).is_none());
assert!(cache.get(&20).is_some());
}
#[tokio::test]
async fn invalidate_all() {
let mut cache = Cache::new(100);
cache.reconfigure_for_testing();
// Make the cache exterior immutable.
let cache = cache;
cache.insert("a", "alice").await;
cache.insert("b", "bob").await;
cache.insert("c", "cindy").await;
assert_eq!(cache.get(&"a"), Some("alice"));
assert_eq!(cache.get(&"b"), Some("bob"));
assert_eq!(cache.get(&"c"), Some("cindy"));
cache.sync();
cache.invalidate_all();
cache.sync();
cache.insert("d", "david").await;
cache.sync();
assert!(cache.get(&"a").is_none());
assert!(cache.get(&"b").is_none());
assert!(cache.get(&"c").is_none());
assert_eq!(cache.get(&"d"), Some("david"));
}
#[tokio::test]
async fn invalidate_entries_if() -> Result<(), Box<dyn std::error::Error>> {
use std::collections::HashSet;
let mut cache = CacheBuilder::new(100)
.support_invalidation_closures()
.build();
cache.reconfigure_for_testing();
let (clock, mock) = Clock::mock();
cache.set_expiration_clock(Some(clock));
// Make the cache exterior immutable.
let cache = cache;
cache.insert(0, "alice").await;
cache.insert(1, "bob").await;
cache.insert(2, "alex").await;
cache.sync();
mock.increment(Duration::from_secs(5)); // 5 secs from the start.
cache.sync();
assert_eq!(cache.get(&0), Some("alice"));
assert_eq!(cache.get(&1), Some("bob"));
assert_eq!(cache.get(&2), Some("alex"));
let names = ["alice", "alex"].iter().cloned().collect::<HashSet<_>>();
cache.invalidate_entries_if(move |_k, &v| names.contains(v))?;
assert_eq!(cache.invalidation_predicate_count(), 1);
mock.increment(Duration::from_secs(5)); // 10 secs from the start.
cache.insert(3, "alice").await;
// Run the invalidation task and wait for it to finish. (TODO: Need a better way than sleeping)
cache.sync(); // To submit the invalidation task.
std::thread::sleep(Duration::from_millis(200));
cache.sync(); // To process the task result.
std::thread::sleep(Duration::from_millis(200));
assert!(cache.get(&0).is_none());
assert!(cache.get(&2).is_none());
assert_eq!(cache.get(&1), Some("bob"));
// This should survive as it was inserted after calling invalidate_entries_if.
assert_eq!(cache.get(&3), Some("alice"));
assert_eq!(cache.table_size(), 2);
assert_eq!(cache.invalidation_predicate_count(), 0);
mock.increment(Duration::from_secs(5)); // 15 secs from the start.
cache.invalidate_entries_if(|_k, &v| v == "alice")?;
cache.invalidate_entries_if(|_k, &v| v == "bob")?;
assert_eq!(cache.invalidation_predicate_count(), 2);
// Run the invalidation task and wait for it to finish. (TODO: Need a better way than sleeping)
cache.sync(); // To submit the invalidation task.
std::thread::sleep(Duration::from_millis(200));
cache.sync(); // To process the task result.
std::thread::sleep(Duration::from_millis(200));
assert!(cache.get(&1).is_none());
assert!(cache.get(&3).is_none());
assert_eq!(cache.table_size(), 0);
assert_eq!(cache.invalidation_predicate_count(), 0);
Ok(())
}
#[tokio::test]
async fn time_to_live() {
let mut cache = CacheBuilder::new(100)
.time_to_live(Duration::from_secs(10))
.build();
cache.reconfigure_for_testing();
let (clock, mock) = Clock::mock();
cache.set_expiration_clock(Some(clock));
// Make the cache exterior immutable.
let cache = cache;
cache.insert("a", "alice").await;
cache.sync();
mock.increment(Duration::from_secs(5)); // 5 secs from the start.
cache.sync();
cache.get(&"a");
mock.increment(Duration::from_secs(5)); // 10 secs.
cache.sync();
assert_eq!(cache.get(&"a"), None);
assert!(cache.is_table_empty());
cache.insert("b", "bob").await;
cache.sync();
assert_eq!(cache.table_size(), 1);
mock.increment(Duration::from_secs(5)); // 15 secs.
cache.sync();
assert_eq!(cache.get(&"b"), Some("bob"));
assert_eq!(cache.table_size(), 1);
cache.insert("b", "bill").await;
cache.sync();
mock.increment(Duration::from_secs(5)); // 20 secs
cache.sync();
assert_eq!(cache.get(&"b"), Some("bill"));
assert_eq!(cache.table_size(), 1);
mock.increment(Duration::from_secs(5)); // 25 secs
cache.sync();
assert_eq!(cache.get(&"a"), None);
assert_eq!(cache.get(&"b"), None);
assert!(cache.is_table_empty());
}
#[tokio::test]
async fn time_to_idle() {
let mut cache = CacheBuilder::new(100)
.time_to_idle(Duration::from_secs(10))
.build();
cache.reconfigure_for_testing();
let (clock, mock) = Clock::mock();
cache.set_expiration_clock(Some(clock));
// Make the cache exterior immutable.
let cache = cache;
cache.insert("a", "alice").await;
cache.sync();
mock.increment(Duration::from_secs(5)); // 5 secs from the start.
cache.sync();
assert_eq!(cache.get(&"a"), Some("alice"));
mock.increment(Duration::from_secs(5)); // 10 secs.
cache.sync();
cache.insert("b", "bob").await;
cache.sync();
assert_eq!(cache.table_size(), 2);
mock.increment(Duration::from_secs(5)); // 15 secs.
cache.sync();
assert_eq!(cache.get(&"a"), None);
assert_eq!(cache.get(&"b"), Some("bob"));
assert_eq!(cache.table_size(), 1);
mock.increment(Duration::from_secs(10)); // 25 secs
cache.sync();
assert_eq!(cache.get(&"a"), None);
assert_eq!(cache.get(&"b"), None);
assert!(cache.is_table_empty());
}
#[tokio::test]
async fn get_or_insert_with() {
let cache = Cache::new(100);
const KEY: u32 = 0;
// This test will run five async tasks:
//
// Task1 will be the first task to call `get_or_insert_with` for a key, so
// its async block will be evaluated and then a &str value "task1" will be
// inserted to the cache.
let task1 = {
let cache1 = cache.clone();
async move {
// Call `get_or_insert_with` immediately.
let v = cache1
.get_or_insert_with(KEY, async {
// Wait for 300 ms and return a &str value.
Timer::after(Duration::from_millis(300)).await;
"task1"
})
.await;
assert_eq!(v, "task1");
}
};
// Task2 will be the second task to call `get_or_insert_with` for the same
// key, so its async block will not be evaluated. Once task1's async block
// finishes, it will get the value inserted by task1's async block.
let task2 = {
let cache2 = cache.clone();
async move {
// Wait for 100 ms before calling `get_or_insert_with`.
Timer::after(Duration::from_millis(100)).await;
let v = cache2
.get_or_insert_with(KEY, async { unreachable!() })
.await;
assert_eq!(v, "task1");
}
};
// Task3 will be the third task to call `get_or_insert_with` for the same
// key. By the time it calls, task1's async block should have finished
// already and the value should be already inserted to the cache. So its
// async block will not be evaluated and will get the value insert by task1's
// async block immediately.
let task3 = {
let cache3 = cache.clone();
async move {
// Wait for 400 ms before calling `get_or_insert_with`.
Timer::after(Duration::from_millis(400)).await;
let v = cache3
.get_or_insert_with(KEY, async { unreachable!() })
.await;
assert_eq!(v, "task1");
}
};
// Task4 will call `get` for the same key. It will call when task1's async
// block is still running, so it will get none for the key.
let task4 = {
let cache4 = cache.clone();
async move {
// Wait for 200 ms before calling `get`.
Timer::after(Duration::from_millis(200)).await;
let maybe_v = cache4.get(&KEY);
assert!(maybe_v.is_none());
}
};
// Task5 will call `get` for the same key. It will call after task1's async
// block finished, so it will get the value insert by task1's async block.
let task5 = {
let cache5 = cache.clone();
async move {
// Wait for 400 ms before calling `get`.
Timer::after(Duration::from_millis(400)).await;
let maybe_v = cache5.get(&KEY);
assert_eq!(maybe_v, Some("task1"));
}
};
futures_util::join!(task1, task2, task3, task4, task5);
}
#[tokio::test]
async fn get_or_try_insert_with() {
use std::sync::Arc;
// Note that MyError does not implement std::error::Error trait
// like anyhow::Error.
#[derive(Debug)]
pub struct MyError(String);
type MyResult<T> = Result<T, Arc<MyError>>;
let cache = Cache::new(100);
const KEY: u32 = 0;
// This test will run eight async tasks:
//
// Task1 will be the first task to call `get_or_insert_with` for a key, so
// its async block will be evaluated and then an error will be returned.
// Nothing will be inserted to the cache.
let task1 = {
let cache1 = cache.clone();
async move {
// Call `get_or_try_insert_with` immediately.
let v = cache1
.get_or_try_insert_with(KEY, async {
// Wait for 300 ms and return an error.
Timer::after(Duration::from_millis(300)).await;
Err(MyError("task1 error".into()))
})
.await;
assert!(v.is_err());
}
};
// Task2 will be the second task to call `get_or_insert_with` for the same
// key, so its async block will not be evaluated. Once task1's async block
// finishes, it will get the same error value returned by task1's async
// block.
let task2 = {
let cache2 = cache.clone();
async move {
// Wait for 100 ms before calling `get_or_try_insert_with`.
Timer::after(Duration::from_millis(100)).await;
let v: MyResult<_> = cache2
.get_or_try_insert_with(KEY, async { unreachable!() })
.await;
assert!(v.is_err());
}
};
// Task3 will be the third task to call `get_or_insert_with` for the same
// key. By the time it calls, task1's async block should have finished
// already, but the key still does not exist in the cache. So its async block
// will be evaluated and then an okay &str value will be returned. That value
// will be inserted to the cache.
let task3 = {
let cache3 = cache.clone();
async move {
// Wait for 400 ms before calling `get_or_try_insert_with`.
Timer::after(Duration::from_millis(400)).await;
let v: MyResult<_> = cache3
.get_or_try_insert_with(KEY, async {
// Wait for 300 ms and return an Ok(&str) value.
Timer::after(Duration::from_millis(300)).await;
Ok("task3")
})
.await;
assert_eq!(v.unwrap(), "task3");
}
};
// Task4 will be the fourth task to call `get_or_insert_with` for the same
// key. So its async block will not be evaluated. Once task3's async block
// finishes, it will get the same okay &str value.
let task4 = {
let cache4 = cache.clone();
async move {
// Wait for 500 ms before calling `get_or_try_insert_with`.
Timer::after(Duration::from_millis(500)).await;
let v: MyResult<_> = cache4
.get_or_try_insert_with(KEY, async { unreachable!() })
.await;
assert_eq!(v.unwrap(), "task3");
}
};
// Task5 will be the fifth task to call `get_or_insert_with` for the same
// key. So its async block will not be evaluated. By the time it calls,
// task3's async block should have finished already, so its async block will
// not be evaluated and will get the value insert by task3's async block
// immediately.
let task5 = {
let cache5 = cache.clone();
async move {
// Wait for 800 ms before calling `get_or_try_insert_with`.
Timer::after(Duration::from_millis(800)).await;
let v: MyResult<_> = cache5
.get_or_try_insert_with(KEY, async { unreachable!() })
.await;
assert_eq!(v.unwrap(), "task3");
}
};
// Task6 will call `get` for the same key. It will call when task1's async
// block is still running, so it will get none for the key.
let task6 = {
let cache6 = cache.clone();
async move {
// Wait for 200 ms before calling `get`.
Timer::after(Duration::from_millis(200)).await;
let maybe_v = cache6.get(&KEY);
assert!(maybe_v.is_none());
}
};
// Task7 will call `get` for the same key. It will call after task1's async
// block finished with an error. So it will get none for the key.
let task7 = {
let cache7 = cache.clone();
async move {
// Wait for 400 ms before calling `get`.
Timer::after(Duration::from_millis(400)).await;
let maybe_v = cache7.get(&KEY);
assert!(maybe_v.is_none());
}
};
// Task8 will call `get` for the same key. It will call after task3's async
// block finished, so it will get the value insert by task3's async block.
let task8 = {
let cache8 = cache.clone();
async move {
// Wait for 800 ms before calling `get`.
Timer::after(Duration::from_millis(800)).await;
let maybe_v = cache8.get(&KEY);
assert_eq!(maybe_v, Some("task3"));
}
};
futures_util::join!(task1, task2, task3, task4, task5, task6, task7, task8);
}
#[tokio::test]
// https://github.com/moka-rs/moka/issues/43
async fn handle_panic_in_get_or_insert_with() {
use tokio::time::{sleep, Duration};
let cache = Cache::new(16);
let semaphore = Arc::new(tokio::sync::Semaphore::new(0));
{
let cache_ref = cache.clone();
let semaphore_ref = semaphore.clone();
tokio::task::spawn(async move {
let _ = cache_ref
.get_or_insert_with(1, async move {
semaphore_ref.add_permits(1);
sleep(Duration::from_millis(50)).await;
panic!("Panic during get_or_try_insert_with");
})
.await;
});
}
let _ = semaphore.acquire().await.expect("semaphore acquire failed");
assert_eq!(cache.get_or_insert_with(1, async { 5 }).await, 5);
}
#[tokio::test]
// https://github.com/moka-rs/moka/issues/43
async fn handle_panic_in_get_or_try_insert_with() {
use tokio::time::{sleep, Duration};
let cache = Cache::new(16);
let semaphore = Arc::new(tokio::sync::Semaphore::new(0));
{
let cache_ref = cache.clone();
let semaphore_ref = semaphore.clone();
tokio::task::spawn(async move {
let _ = cache_ref
.get_or_try_insert_with(1, async move {
semaphore_ref.add_permits(1);
sleep(Duration::from_millis(50)).await;
panic!("Panic during get_or_try_insert_with");
})
.await as Result<_, Arc<Infallible>>;
});
}
let _ = semaphore.acquire().await.expect("semaphore acquire failed");
assert_eq!(
cache.get_or_try_insert_with(1, async { Ok(5) }).await as Result<_, Arc<Infallible>>,
Ok(5)
);
}
#[tokio::test]
// https://github.com/moka-rs/moka/issues/59
async fn abort_get_or_insert_with() {
use tokio::time::{sleep, Duration};
let cache = Cache::new(16);
let semaphore = Arc::new(tokio::sync::Semaphore::new(0));
let handle;
{
let cache_ref = cache.clone();
let semaphore_ref = semaphore.clone();
handle = tokio::task::spawn(async move {
let _ = cache_ref
.get_or_insert_with(1, async move {
semaphore_ref.add_permits(1);
sleep(Duration::from_millis(50)).await;
unreachable!();
})
.await;
});
}
let _ = semaphore.acquire().await.expect("semaphore acquire failed");
handle.abort();
assert_eq!(cache.get_or_insert_with(1, async { 5 }).await, 5);
}
#[tokio::test]
// https://github.com/moka-rs/moka/issues/59
async fn abort_get_or_try_insert_with() {
use tokio::time::{sleep, Duration};
let cache = Cache::new(16);
let semaphore = Arc::new(tokio::sync::Semaphore::new(0));
let handle;
{
let cache_ref = cache.clone();
let semaphore_ref = semaphore.clone();
handle = tokio::task::spawn(async move {
let _ = cache_ref
.get_or_try_insert_with(1, async move {
semaphore_ref.add_permits(1);
sleep(Duration::from_millis(50)).await;
unreachable!();
})
.await as Result<_, Arc<Infallible>>;
});
}
let _ = semaphore.acquire().await.expect("semaphore acquire failed");
handle.abort();
assert_eq!(
cache.get_or_try_insert_with(1, async { Ok(5) }).await as Result<_, Arc<Infallible>>,
Ok(5)
);
}
}