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Make RegexCache thread-safe

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This commit is contained in:
Eelco Dolstra 2024-05-31 19:18:38 +02:00
parent b36aa04b53
commit fbbca59453
1 changed files with 13 additions and 7 deletions
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14
src/libexpr/primops.cc
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@ -4061,18 +4061,24 @@ static RegisterPrimOp primop_convertHash({
});
struct RegexCache
{
struct State
{
// TODO use C++20 transparent comparison when available
std::unordered_map<std::string_view, std::regex> cache;
std::list<std::string> keys;
};
Sync<State> state_;
std::regex get(std::string_view re)
{
auto it = cache.find(re);
if (it != cache.end())
auto state(state_.lock());
auto it = state->cache.find(re);
if (it != state->cache.end())
return it->second;
keys.emplace_back(re);
return cache.emplace(keys.back(), std::regex(keys.back(), std::regex::extended)).first->second;
state->keys.emplace_back(re);
return state->cache.emplace(state->keys.back(), std::regex(state->keys.back(), std::regex::extended)).first->second;
}
};