act::LocalChunkStore Class Reference

Detailed Description

A local chunk store for storing a given node's chunks in memory.

This class provides a thread-safe implementation of a chunk store that stores chunks in memory. It allows for writing, reading, and waiting for chunks to be available.

#include <actionengine/stores/local_chunk_store.h>

Inheritance diagram for act::LocalChunkStore:

Public Member Functions
absl::StatusOr< std::reference_wrapper< const Chunk > >	GetRef (int64_t seq, absl::Duration timeout) override
	Same as Get(), but returns a reference to the chunk instead of copying it.
absl::StatusOr< std::reference_wrapper< const Chunk > >	GetRefByArrivalOrder (int64_t arrival_offset, absl::Duration timeout) override
	Same as GetByArrivalOrder(), but returns a reference to the chunk instead of copying it.
absl::StatusOr< std::optional< Chunk > >	Pop (int64_t seq) override
	Pop a chunk from the store by its sequence number.
absl::Status	Put (int64_t seq, Chunk chunk, bool final) override
	Put a chunk into the store with the specified sequence number.
absl::Status	CloseWritesWithStatus (absl::Status) override
	Closes the store for writes, allowing for finalization of the store.
Public Member Functions inherited from act::ChunkStore
virtual absl::StatusOr< Chunk >	Get (int64_t seq, absl::Duration timeout)
	Get a chunk by its sequence number from the represented store.
virtual absl::StatusOr< Chunk >	GetByArrivalOrder (int64_t arrival_order, absl::Duration timeout)
	Same as Get(), but retrieves the chunk by its arrival order (rank by arrival time) instead of sequence number.

Member Function Documentation

CloseWritesWithStatus()

absl::Status act::LocalChunkStore::CloseWritesWithStatus ( absl::Status status )

overridevirtual

Closes the store for writes, allowing for finalization of the store.

This method is used to indicate that no further writes will be made to the store. It can be used to finalize the store, ensuring that no new writes are allowed. Any pending read operations that are waiting for new writes will be notified that no further writes will occur.

Parameters

status

The status to set for the store, indicating whether it was closed successfully or with an error.

Returns

An absl::Status indicating the success or failure of the operation.

Implements act::ChunkStore.

GetRef()

absl::StatusOr< std::reference_wrapper< const Chunk > > act::LocalChunkStore::GetRef ( int64_t seq, absl::Duration timeout )

overridevirtual

Same as Get(), but returns a reference to the chunk instead of copying it.

This allows for more efficient access to the chunk data in cases where data lives in-process, such as in-memory storage.

Parameters

seq	The sequence number of the chunk to retrieve.
timeout	The maximum duration to wait for the chunk to become available.

Returns

A reference to a Chunk object containing the data associated with the specified sequence number, or an absl::Status indicating an error if the chunk could not be retrieved due to timeout or other issues.

Reimplemented from act::ChunkStore.

GetRefByArrivalOrder()

absl::StatusOr< std::reference_wrapper< const Chunk > > act::LocalChunkStore::GetRefByArrivalOrder ( int64_t seq, absl::Duration timeout )

overridevirtual

Same as GetByArrivalOrder(), but returns a reference to the chunk instead of copying it.

This allows for more efficient access to the chunk data in cases where data lives in-process, such as in-memory storage.

Parameters

seq	The sequence number of the chunk to retrieve.
timeout	The maximum duration to wait for the chunk to become available.

Returns

A reference to a Chunk object containing the data associated with the specified sequence number, or an absl::Status indicating an error if the chunk could not be retrieved due to timeout or other issues.

Reimplemented from act::ChunkStore.

Pop()

absl::StatusOr< std::optional< Chunk > > act::LocalChunkStore::Pop ( int64_t seq )

overridevirtual

Pop a chunk from the store by its sequence number.

This method removes the chunk associated with the specified sequence number from the store and returns it. If no chunk with that sequence number exists, it returns std::nullopt.

Parameters

seq	The sequence number of the chunk to pop.

Returns

An absl::StatusOr<std::optional<Chunk>> containing the popped chunk, or std::nullopt if no chunk with that sequence number exists. If an error occurs during the operation, it returns an absl::Status indicating the error.

Implements act::ChunkStore.

Put()

absl::Status act::LocalChunkStore::Put ( int64_t seq, Chunk chunk, bool final )

overridevirtual

Put a chunk into the store with the specified sequence number.

This method allows you to store a chunk of data in the store, associating it with a specific sequence number. If the final parameter is set to true, it indicates that this is the last chunk in a sequence, and no further chunks with a higher sequence number will be added.

Parameters

seq	The sequence number to associate with the chunk. Putting the same seq twice is an error.
chunk	The Chunk of data to put in the store.
final	A boolean indicating whether this is the final chunk in a sequence. If true, it indicates that no further chunks with a higher sequence number will be added to the store.

Note

Complete and correct implementations of this method may become quite complex, as they need to handle various edge cases, such as:

• ensuring that the sequence number is unique,
• managing the finality of chunks and communicating that to readers,
• handling concurrent writes and reads without data corruption or loss.

LocalChunkStore is a good example of such an implementation. redis::ChunkStore is another example, which implements this interface on top of Redis, leveraging its atomicity within Lua scripts to ensure that writes are safe and consistent.

ChunkStore::Put

Implements act::ChunkStore.

---

The documentation for this class was generated from the following files:

• /Users/helenapankov/dev/actionengine/src/actionengine/stores/local_chunk_store.h
• /Users/helenapankov/dev/actionengine/src/actionengine/stores/local_chunk_store.cc