vlink::AckManager Class Reference

Thread-safe coordinator that pairs RPC requests with their acknowledgements. More...

#include <ack_manager.h>

Collaboration diagram for vlink::AckManager:

Public Types
using	ProcessCallback = MoveFunction< bool()>
	Send callback supplied to process(); returning false aborts the wait. More...
using	NotifyCallback = MoveFunction< void()>
	Optional fill-in callback invoked from inside notify() under the lock. More...
using	RequestPtr = std::shared_ptr< Request >
	Shared handle representing a single in-flight RPC request. More...

Public Member Functions
	AckManager () noexcept
	Constructs an empty manager. More...
	~AckManager () noexcept
	Destroys the manager and releases any remaining pending records. More...
RequestPtr	create_request () noexcept
	Allocates a new request token with the next monotonic sequence number. More...
bool	process (RequestPtr request, int ms, ProcessCallback &&process_callback) noexcept
	Publishes request via process_callback and blocks until it is acknowledged. More...
bool	notify (RequestPtr request, NotifyCallback &&notify_callback=nullptr) noexcept
	Resolves request and, if supplied, runs notify_callback before waking the caller. More...
bool	remove (RequestPtr request) noexcept
	Cancels request without waking any waiter. More...
void	clear () noexcept
	Interrupts every pending wait and refuses new ones until reset_interrupted(). More...
void	reset_interrupted () noexcept
	Permits new process() calls again after a previous clear(). More...

Detailed Description

Thread-safe coordinator that pairs RPC requests with their acknowledgements.

Stores a sorted set of in-flight RequestPtr handles indexed by their sequence number and uses one condition variable per request to wake the blocked caller when notify() arrives. Used internally by every ClientImpl subclass to provide the blocking call() semantics exposed at the public Client API.

Member Typedef Documentation

NotifyCallback

using vlink::AckManager::NotifyCallback = MoveFunction<void()>

Optional fill-in callback invoked from inside notify() under the lock.

Lets the transport copy the response into the caller's buffer before the waiting thread is resumed. May be nullptr.

ProcessCallback

using vlink::AckManager::ProcessCallback = MoveFunction<bool()>

Send callback supplied to process(); returning false aborts the wait.

Invoked while the request is already part of the pending set, so any concurrent notify() that arrives before the callback returns is safe.

RequestPtr

using vlink::AckManager::RequestPtr = std::shared_ptr<Request>

Shared handle representing a single in-flight RPC request.

Returned by create_request() and consumed by process(), notify() and remove(). Equality is implied by the monotonic sequence number.

Constructor & Destructor Documentation

AckManager()

vlink::AckManager::AckManager ( )

noexcept

Constructs an empty manager.

~AckManager()

vlink::AckManager::~AckManager ( )

noexcept

Destroys the manager and releases any remaining pending records.

Member Function Documentation

clear()

void vlink::AckManager::clear ( )

noexcept

Interrupts every pending wait and refuses new ones until reset_interrupted().

Bumps the generation counter, drains the pending set into a local copy and notifies every condition variable so that the affected process() calls return false. Used during node shutdown to avoid blocking destructors.

create_request()

RequestPtr vlink::AckManager::create_request ( )

noexcept

Allocates a new request token with the next monotonic sequence number.

Returns

Shared handle ready to be passed to process().

notify()

bool vlink::AckManager::notify ( RequestPtr  request, NotifyCallback &&  notify_callback = nullptr  )

noexcept

Resolves request and, if supplied, runs notify_callback before waking the caller.

Erases the entry from the pending set, executes notify_callback while holding the request lock so the caller observes the side effects before resuming, and signals the condition variable.

Parameters

request	Token to acknowledge.
notify_callback	Optional callable executed before notification.

Returns

true if the request was still pending and was resolved; false otherwise.

process()

bool vlink::AckManager::process ( RequestPtr  request, int  ms, ProcessCallback &&  process_callback  )

noexcept

Publishes request via process_callback and blocks until it is acknowledged.

The method performs four steps:

1. Registers request in the pending set; returns false straight away if clear() has been called and not yet reset.
2. Invokes process_callback to dispatch the request. When the callback returns false the entry is removed and process() also returns false.
3. Sleeps on a per-request condition variable until notify() / remove() fires or ms expires. A negative ms blocks forever.
4. Returns true on a successful notify(); false on timeout, abort or clear() interruption.

Parameters

request	Token obtained from create_request().
ms	Wait budget in milliseconds; negative for unlimited.
process_callback	Send callback; returning false aborts the wait.

Returns

true on acknowledgement, false otherwise.

remove()

bool vlink::AckManager::remove ( RequestPtr  request )

noexcept

Cancels request without waking any waiter.

Parameters

request

Token to drop from the pending set.

Returns

true if the entry existed and was removed; false otherwise.

reset_interrupted()

void vlink::AckManager::reset_interrupted ( )

noexcept

Permits new process() calls again after a previous clear().

Does not unblock requests interrupted by the earlier clear(); the generation tag they were created in remains cancelled.

---

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

• include/vlink/impl/ack_manager.h