Struct CowTransactionGuard 

pub struct CowTransactionGuard<'tra, ITEM: Send + Debug> { /* private fields */ }

A guard which guards the CoW read/write operation. During this operation, the instance is borrowed and copied or clonned or default or new instance created.

This method of modifying does not require to release all borrows i.e CowReadGuard. Instead the value in the base will be replaced and anyone who will request the borrow after the update will see the new value. The rest who keeps borrow would still use old value.

Implementations

impl<'tra, ITEM: Send + Debug> CowTransactionGuard<'tra, ITEM>

pub fn get_previous(&self) -> &ITEM

Returns the previous reference to the item (old value) which will be replaced.

pub fn completed(self, try_update: bool) -> Result<(), (Self, CowGuardError)>

Completes the transaction by attempting to replace the old item with new item in the base. If argument try_update is set to true, the completed will not block, but return an error to repeat the attempt later.

Arguments

The instance is consumed.

try_update - if set to true does not block if exclusive lock is pending.

Returns

A Result is returned with:

• Result::Ok with the guard is returned.

• Result::Err with the error is returned:

• CowGuardError::Poisoned - if the exclusive was poisoned i.e thread panicked.

• CowGuardError::ExclusiveLockPending - if the argument try_borrow is set to true.

Trait Implementations

impl<'tra, ITEM: Debug + Send + Debug> Debug for CowTransactionGuard<'tra, ITEM>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<'tra, ITEM: Send + Debug> Deref for CowTransactionGuard<'tra, ITEM>

type Target = ITEM

The resulting type after dereferencing.

fn deref(&self) -> &Self::Target

Dereferences the value.

impl<'tra, ITEM: Send + Debug> DerefMut for CowTransactionGuard<'tra, ITEM>

fn deref_mut(&mut self) -> &mut Self::Target

Mutably dereferences the value.