Struct serenity::CACHE

pub struct CACHE { /* fields omitted */ }

A mutable and lazily-initialized static binding. It can be accessed across any function and in any context.

This Cache instance is updated for every event received, so you do not need to maintain your own cache.

See the cache module documentation for more details.

The Cache itself is wrapped within an RwLock, which allows for multiple readers or at most one writer at a time across threads. This means that you may have multiple commands reading from the Cache concurrently.

Examples

Retrieve the current user's Id, by opening a Read guard:

use serenity::CACHE;

println!("{}", CACHE.read().unwrap().user.id);

By unwrap()ing, the thread managing an event dispatch will be blocked until the guard can be opened.

If you do not want to block the current thread, you may instead use RwLock::try_read. Refer to RwLock's documentation in the stdlib for more information.

Methods from __Deref<Target = RwLock<Cache>>

fn read(&self) -> Result<RwLockReadGuard<T>, PoisonError<RwLockReadGuard<T>>>

Locks this rwlock with shared read access, blocking the current thread until it can be acquired.

The calling thread will be blocked until there are no more writers which hold the lock. There may be other readers currently inside the lock when this method returns. This method does not provide any guarantees with respect to the ordering of whether contentious readers or writers will acquire the lock first.

Returns an RAII guard which will release this thread's shared access once it is dropped.

Errors

This function will return an error if the RwLock is poisoned. An RwLock is poisoned whenever a writer panics while holding an exclusive lock. The failure will occur immediately after the lock has been acquired.

Panics

This function might panic when called if the lock is already held by the current thread.

fn try_read(
    &self
) -> Result<RwLockReadGuard<T>, TryLockError<RwLockReadGuard<T>>>

Attempts to acquire this rwlock with shared read access.

If the access could not be granted at this time, then Err is returned. Otherwise, an RAII guard is returned which will release the shared access when it is dropped.

This function does not block.

This function does not provide any guarantees with respect to the ordering of whether contentious readers or writers will acquire the lock first.

Errors

This function will return an error if the RwLock is poisoned. An RwLock is poisoned whenever a writer panics while holding an exclusive lock. An error will only be returned if the lock would have otherwise been acquired.

fn write(&self) -> Result<RwLockWriteGuard<T>, PoisonError<RwLockWriteGuard<T>>>

Locks this rwlock with exclusive write access, blocking the current thread until it can be acquired.

This function will not return while other writers or other readers currently have access to the lock.

Returns an RAII guard which will drop the write access of this rwlock when dropped.

Errors

This function will return an error if the RwLock is poisoned. An RwLock is poisoned whenever a writer panics while holding an exclusive lock. An error will be returned when the lock is acquired.

Panics

This function might panic when called if the lock is already held by the current thread.

fn try_write(
    &self
) -> Result<RwLockWriteGuard<T>, TryLockError<RwLockWriteGuard<T>>>

Attempts to lock this rwlock with exclusive write access.

If the lock could not be acquired at this time, then Err is returned. Otherwise, an RAII guard is returned which will release the lock when it is dropped.

This function does not block.

This function does not provide any guarantees with respect to the ordering of whether contentious readers or writers will acquire the lock first.

Errors

This function will return an error if the RwLock is poisoned. An RwLock is poisoned whenever a writer panics while holding an exclusive lock. An error will only be returned if the lock would have otherwise been acquired.

fn is_poisoned(&self) -> bool

Determines whether the lock is poisoned.

If another thread is active, the lock can still become poisoned at any time. You should not trust a false value for program correctness without additional synchronization.

fn into_inner(self) -> Result<T, PoisonError<T>>

Consumes this RwLock, returning the underlying data.

Errors

This function will return an error if the RwLock is poisoned. An RwLock is poisoned whenever a writer panics while holding an exclusive lock. An error will only be returned if the lock would have otherwise been acquired.

Trait Implementations

impl __Deref for CACHE

type Target = RwLock<Cache>

The resulting type after dereferencing

fn deref(&self) -> &RwLock<Cache>

The method called to dereference a value

impl LazyStatic for CACHE

fn initialize(lazy: &Self)