real::detail::shared_dfa_slot Struct Reference

Process-wide shared DFA transition caches keyed by regex_immutables*. More...

#include <onepass.hpp>

Public Attributes
std::mutex	mu
	Guards every DFA below: warm-up and scan alike.
std::optional< lazy_dfa >	fwd
	Forward lazy DFA, absent until a route first needs it.
std::optional< reverse_dfa >	rev
	Reverse lazy DFA, for finding a match start from its end.
std::optional< reverse_dfa >	il_prefix_rev
std::atomic< bool >	il_warmed {false}
	True after this regex has been IL-candidate-scanned at least once (any size). Cold first scan keeps the high regex_immutables::il_min_haystack floor; warm scans use il_warm_floor. Not "il_prefix_rev is built" — a always-<floor corpus would never build the reverse DFA and so would never drop the floor.
std::atomic< const regex_immutables * >	owner {nullptr}
	The regex this slot belongs to, or null once erase_shared_dfas has retired it.

Detailed Description

Process-wide shared DFA transition caches keyed by regex_immutables*.

Thread-safe: map insert/erase under shared_dfa_map_mu, DFA warm/scan under mu. Slots are shared_ptr so a concurrent erase_shared_dfas (from a destructor) cannot free a slot a thread is still scanning — the slot dies when the last holder, map or thread-local cache, releases it.

Member Data Documentation

il_prefix_rev

std::optional<reverse_dfa> real::detail::shared_dfa_slot::il_prefix_rev

Reverse DFA over the inner-literal PREFIX sub-program only.

owner

std::atomic<const regex_immutables*> real::detail::shared_dfa_slot::owner {nullptr}

The regex this slot belongs to, or null once erase_shared_dfas has retired it.

This is what validates a thread's last-hit cache in shared_dfa_for — a cached slot is still this regex's slot exactly while owner == immut. The predecessor was a single process-wide epoch counter bumped on every erase, which meant ANY regex's destruction invalidated EVERY thread's cache and sent them all back to shared_dfa_map_mu — the global mutex the cache exists to avoid, once per inner-literal candidate. Ownership is per slot, so one regex dying now costs only the threads that were actually using it.

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

• include/real/automata/onepass.hpp