morph::journal::SessionLog Class Reference

Full-fidelity, in-memory log of one model instance's executed actions. More...

#include <journal.hpp>

Inheritance diagram for morph::journal::SessionLog:

Public Member Functions
	SessionLog (::morph::exec::IExecutor &owner)
	Constructs an empty session log belonging to owner.
void	append (LogEntry entry) override
	Appends entry, assigning a monotonically increasing seq, on the owner.
void	flush () override
	No-op — checkpoint() is this class's real commit point. Callable anywhere.
std::vector< LogEntry >	entries (std::string_view entityKey={}) const override
	Returns the full history (or one entity's slice of it) in append order. On the owner.
::morph::exec::IExecutor *	owner () const noexcept override
	The executor given at construction.
std::unique_ptr<::morph::model::detail::IModelHolder >	undoLast (std::string_view modelTypeId, ::morph::model::detail::ModelRegistryFactory &registry=::morph::model::detail::defaultRegistry(), ::morph::model::detail::ActionDispatcher &dispatcher=::morph::model::detail::defaultDispatcher())
	Drops the most recently appended entry and replays everything that remains against a fresh model instance, reconstructing the state the model was in immediately before that entry executed. On the owner.
void	checkpoint (IActionLog &durableSink, ::morph::model::detail::ActionDispatcher &dispatcher=::morph::model::detail::defaultDispatcher())
	Coalesces entries appended since the last checkpoint and forwards the reduced set, in order, to durableSink; then flushes it. On the owner.
::morph::async::Completion< std::vector< LogEntry > >	entries (::morph::exec::IExecutor &replyExec, std::string entityKey={}) const
	Returns recorded entries in append order, read on the log's owner and delivered on replyExec.
::morph::async::Completion< bool >	flush (::morph::exec::IExecutor &replyExec)
	Pushes buffered entries to the durable backend on the log's owner; the answer is delivered on replyExec.
Public Member Functions inherited from morph::journal::IActionLog
::morph::async::Completion< std::vector< LogEntry > >	entries (::morph::exec::IExecutor &replyExec, std::string entityKey={}) const
	Returns recorded entries in append order, read on the log's owner and delivered on replyExec.
::morph::async::Completion< bool >	flush (::morph::exec::IExecutor &replyExec)
	Pushes buffered entries to the durable backend on the log's owner; the answer is delivered on replyExec.

Protected Member Functions
::morph::async::Completion< std::vector< LogEntry > >	askEntries (::morph::exec::IExecutor &replyExec, std::string entityKey) const override
	Reads the history on the owner, delivered on replyExec.
Protected Member Functions inherited from morph::journal::IActionLog
virtual ::morph::async::Completion< bool >	askFlush (::morph::exec::IExecutor &replyExec)
	What flush(replyExec) asks. The default flushes where it is called, for an implementation with no owner; one with an owner flushes there.

Detailed Description

Full-fidelity, in-memory log of one model instance's executed actions.

Attach directly via IModelHolder::attachActionLog — every successfully executed loggable action is appended here in order, regardless of any ActionLogPolicy::coalesce setting. This full history is the raw material for undoLast(). checkpoint() is the one place coalescing actually happens: entries accumulated since the last checkpoint are reduced by (modelType, entityKey, actionType) — keeping only the latest occurrence where the action's policy says coalesce == true, keeping every occurrence otherwise — and only that reduced set reaches the durable sink.

One owner

The history and the checkpoint watermark belong to the executor given at construction, which must run one task at a time. append() runs there — at once when called on it, posted from a model's strand. entries(), undoLast() and checkpoint() run only there; a caller elsewhere reads through entries(replyExec, entityKey). Because a checkpoint and every append are tasks of the one owner, a checkpoint's slice-and-forward is never interleaved with an append or with another checkpoint. See docs/spec/journal/journal.md, "One owner".

Definition at line 338 of file journal.hpp.

Constructor & Destructor Documentation

SessionLog()

morph::journal::SessionLog::SessionLog ( ::morph::exec::IExecutor & owner )

inlineexplicit

Constructs an empty session log belonging to owner.

Parameters

owner

The executor every access runs on; must run one task at a time. Borrowed: it must outlive this log and run what it posts.

Definition at line 346 of file journal.hpp.

Member Function Documentation

append()

void morph::journal::SessionLog::append ( LogEntry entry )

inlineoverridevirtual

Appends entry, assigning a monotonically increasing seq, on the owner.

Always full fidelity: this is what undoLast() walks back through, so nothing is coalesced or dropped here.

Parameters

entry

Entry to append; seq is overwritten regardless of the input value.

Implements morph::journal::IActionLog.

Definition at line 355 of file journal.hpp.

flush() [1/2]

void morph::journal::SessionLog::flush ( )

inlineoverridevirtual

No-op — checkpoint() is this class's real commit point. Callable anywhere.

Implements morph::journal::IActionLog.

Definition at line 363 of file journal.hpp.

entries() [1/2]

std::vector< LogEntry > morph::journal::SessionLog::entries ( std::string_view entityKey = {} ) const

inlinenodiscardoverridevirtual

Returns the full history (or one entity's slice of it) in append order. On the owner.

Parameters

entityKey

If non-empty, restricts the result to that entity's entries.

Returns

Matching entries, in append order.

Implements morph::journal::IActionLog.

Definition at line 369 of file journal.hpp.

owner()

::morph::exec::IExecutor * morph::journal::SessionLog::owner ( ) const

inlinenodiscardoverridevirtualnoexcept

The executor given at construction.

Returns

The owner.

Reimplemented from morph::journal::IActionLog.

Definition at line 375 of file journal.hpp.

undoLast()

std::unique_ptr<::morph::model::detail::IModelHolder > morph::journal::SessionLog::undoLast ( std::string_view modelTypeId, ::morph::model::detail::ModelRegistryFactory & registry = ::morph::model::detail::defaultRegistry(), ::morph::model::detail::ActionDispatcher & dispatcher = ::morph::model::detail::defaultDispatcher() )

inline

Drops the most recently appended entry and replays everything that remains against a fresh model instance, reconstructing the state the model was in immediately before that entry executed. On the owner.

No inverse/undo operations are needed on the action types themselves — this reuses replay() over a shorter prefix of the same log. A no-op (returns a freshly created, un-replayed holder) if the log is empty.

Undo only rewinds this in-memory history; it never moves the checkpoint watermark, which is keyed by entry seq (see checkpoint()). Undoing an entry a prior checkpoint() already forwarded does not un-forward it: the durable sink is append-only, so that entry stays durable while the reconstructed history diverges from it. A later checkpoint() never re-forwards a coalesced-away, already-committed entry. Applications that need to durably reverse a checkpointed action must record a compensating action, not rely on undoLast().

Replays through replay() with its default payload-schema settings. That gate cannot fire here in practice: the entries being replayed were appended by this same process, so their fingerprints are this build's by construction. Undo is not a cross-version path.

Synchronous: it returns the reconstructed holder, and its caller — the application — is the owner.

Parameters

modelTypeId	String type-id of the model to reconstruct.
registry	Model factory registry; defaults to the process-level singleton.
dispatcher	Action dispatcher; defaults to the process-level singleton.

Returns

A freshly created holder with the pre-undo state replayed onto it.

Definition at line 406 of file journal.hpp.

checkpoint()

void morph::journal::SessionLog::checkpoint ( IActionLog & durableSink, ::morph::model::detail::ActionDispatcher & dispatcher = ::morph::model::detail::defaultDispatcher() )

inline

Coalesces entries appended since the last checkpoint and forwards the reduced set, in order, to durableSink; then flushes it. On the owner.

Advances the checkpoint watermark (the seq of the last committed entry) before forwarding, so the batch is consumed even if durableSink's append() or flush() throws: a checkpoint is a forward-only commit point (at-most-once), not a transaction to retry. A no-op if nothing has been appended since the last checkpoint.

Ordering

The whole body is one task of the owner, where every append() runs too, so no append lands between taking the slice and forwarding it, and two checkpoints forward their batches in the order they ran. That is the append-order identity the sink relies on.

Parameters

durableSink	Receives only the coalesced entries — never the raw stream. Driven from this log's owner, so it must share it: its flush() answers only on its own owner.
dispatcher	Supplies each action's coalesce policy; defaults to the process-level singleton (the same one actions were registered against via BRIDGE_REGISTER_ACTION).

Definition at line 443 of file journal.hpp.

askEntries()

::morph::async::Completion< std::vector< LogEntry > > morph::journal::SessionLog::askEntries ( ::morph::exec::IExecutor & replyExec, std::string entityKey ) const

inlinenodiscardoverrideprotectedvirtual

Reads the history on the owner, delivered on replyExec.

Parameters

replyExec	Where the answer is delivered.
entityKey	If non-empty, restricts the result to that entity's entries.

Returns

The matching entries.

Reimplemented from morph::journal::IActionLog.

Definition at line 473 of file journal.hpp.

entries() [2/2]

::morph::async::Completion< std::vector< LogEntry > > morph::journal::IActionLog::entries ( ::morph::exec::IExecutor & replyExec, std::string entityKey = {} ) const

inlinenodiscard

Returns recorded entries in append order, read on the log's owner and delivered on replyExec.

The form for a caller that is not on the owner: a model's strand, an application thread the log does not belong to. The read is ordered after every append() posted to the owner before it.

Parameters

replyExec	Where the answer is delivered, and where the caller attaches to it. Borrowed: it must outlive the completion.
entityKey	If non-empty, restricts the result to that entity's entries.

Returns

The matching entries, in append order.

Definition at line 231 of file action_log.hpp.

flush() [2/2]

::morph::async::Completion< bool > morph::journal::IActionLog::flush ( ::morph::exec::IExecutor & replyExec )

inlinenodiscard

Pushes buffered entries to the durable backend on the log's owner; the answer is delivered on replyExec.

The form of flush() for a caller that is not on the owner. It is ordered after every append() posted to the owner before it.

Parameters

replyExec

Where the answer is delivered. Borrowed: it must outlive the completion.

Returns

true once the entries are durable; rejected with the error flush() would have thrown.

Definition at line 245 of file action_log.hpp.

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

• morph/journal/journal.hpp