Struct ThreadsafePooledIter 

pub struct ThreadsafePooledIter<I, BorrowedItem: ToOwned> { /* private fields */ }

Available on crate feature anchored-pool only.

Convert a CursorLendingIterator into a CursorPooledIterator by storing recently accessed items in reusable buffers.

This effectively allows the iterator to lend out multiple items at once, unlike a lending iterator which can only lend out one. This comes primarily at the cost of extra copying into buffers, and in memory usage. The costs of allocating buffers is likely amortized by their reuse.

Implementations

impl<I, BorrowedItem> ThreadsafePooledIter<I, BorrowedItem>

where BorrowedItem: ToOwned, BorrowedItem::Owned: Default,

pub fn new(iter: I, num_buffers: usize) -> Self

Create a ThreadsafePooledIter that can lend out up to num_buffers items at a time.

Trait Implementations

impl<I, BorrowedItem> CursorPooledIterator for ThreadsafePooledIter<I, BorrowedItem>

where I: CursorLendingIterator, BorrowedItem: ToOwned, for<'lend> LentItem<'lend, I>: Borrow<BorrowedItem>,

fn current(&self) -> Option<Self::Item>

Get the current value the iterator is at, if the iterator is valid.

May need to wait for a buffer to become available.

Potential Panics or Deadlocks

If self.buffer_pool_size() == 0, then this method panics. This method may also cause a deadlock if no buffers are currently available, and the current thread needs to make progress in order to release a buffer.

fn prev(&mut self) -> Option<Self::Item>

Move the iterator one position back, and return the entry at that position. Returns None if the iterator was at the last entry.

May need to wait for a buffer to become available.

Potential Panics or Deadlocks

If self.buffer_pool_size() == 0, then this method panics. This method may also cause a deadlock if no buffers are currently available, and the current thread needs to make progress in order to release a buffer.

fn valid(&self) -> bool

Determine whether the iterator is currently at any value in the collection. If the iterator is invalid, then it is conceptually one position before the first entry and one position after the last entry. (Or, there may be no entries.)

fn try_current(&self) -> Result<Option<Self::Item>, OutOfBuffers>

If a buffer is available, get the current value the iterator is at, if the iterator is valid.

fn try_prev(&mut self) -> Result<Option<Self::Item>, OutOfBuffers>

If a buffer is available, move the iterator one position back, and return the entry at that position. Returns Ok(None) if the iterator was at the first entry.

impl<I: Debug, BorrowedItem: Debug + ToOwned> Debug for ThreadsafePooledIter<I, BorrowedItem>

where BorrowedItem::Owned: Debug,

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

Formats the value using the given formatter.

impl<I, BorrowedItem> PooledIterator for ThreadsafePooledIter<I, BorrowedItem>

where I: CursorLendingIterator, BorrowedItem: ToOwned, for<'lend> LentItem<'lend, I>: Borrow<BorrowedItem>,

fn next(&mut self) -> Option<Self::Item>

Move the iterator one position forwards, and return the entry at that position. Returns None if the iterator was at the last entry.

May need to wait for a buffer to become available.

Potential Panics or Deadlocks

If self.buffer_pool_size() == 0, then this method panics. This method may also cause a deadlock if no buffers are currently available, and the current thread needs to make progress in order to release a buffer.

type Item = ThreadsafePoolItem<<BorrowedItem as ToOwned>::Owned>

The item of this iterator, which likely has a nontrivial drop implementation that returns a buffer to the iterator’s buffer pool.

fn try_next(&mut self) -> Result<Option<Self::Item>, OutOfBuffers>

If a buffer is available, move the iterator one position forwards, and return the entry at that position. Returns Ok(None) if the iterator was at the last entry.

fn buffer_pool_size(&self) -> usize

Get the total number of buffers in the buffer pool, including buffers that are currently in use.

fn available_buffers(&self) -> usize

Get the number of buffers that are currently available.

fn into_lender(self) -> PooledLenderAdapter<Self>

where Self: Sized,

Available on crate feature lender only.

Convert the PooledIterator into a lender::Lender lending iterator which only uses one buffer at a time.

fn into_lending_iterator(self) -> PooledLendingIteratorAdapter<Self>

where Self: Sized,

Available on crate feature lending-iterator only.

Convert the PooledIterator into a lending_iterator::LendingIterator which only uses one buffer at a time.

impl<I, BorrowedItem, Key, Cmp> Seekable<Key, Cmp> for ThreadsafePooledIter<I, BorrowedItem>

where I: CursorLendingIterator + Seekable<Key, Cmp>, BorrowedItem: ToOwned, Key: ?Sized, Cmp: Comparator<Key>, for<'lend> LentItem<'lend, I>: Borrow<BorrowedItem>,

fn reset(&mut self)

Reset the iterator to its initial position, before the first entry and after the last entry (if there are any entries in the collection).

fn seek(&mut self, min_bound: &Key)

Move the iterator to the smallest key which is greater or equal than the provided min_bound.

fn seek_before(&mut self, strict_upper_bound: &Key)

Move the iterator to the greatest key which is strictly less than the provided strict_upper_bound.

fn seek_to_first(&mut self)

Move the iterator to the smallest key in the collection.

fn seek_to_last(&mut self)

Move the iterator to the greatest key in the collection.