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#include "cache.h"
#include "async.h"
#include "coro.h"
#include "helpers.h"
#include <library/cpp/cache/cache.h>
#include <library/cpp/coroutine/engine/impl.h>
#include <library/cpp/coroutine/engine/events.h>
using namespace NAddr;
using namespace NAsyncDns;
class TContDnsCache::TImpl {
using TKey = std::pair<TString, ui16>;
enum EResolveState {
RS_NOT_RESOLVED,
RS_IN_PROGRESS,
RS_RESOLVED,
RS_FAILED,
RS_EXPIRED
};
struct TEntry: public TSimpleRefCount<TEntry> {
TAddrs Addrs_;
TInstant ResolveTimestamp_;
EResolveState State_;
TContSimpleEvent ResolvedEvent_;
TString LastResolveError_;
TEntry(TContExecutor* e)
: State_(RS_NOT_RESOLVED)
, ResolvedEvent_(e)
{
}
};
using TEntryRef = TIntrusivePtr<TEntry>;
public:
inline TImpl(TContExecutor* e, const TCacheOptions& opts)
: Executor_(e)
, Opts_(opts)
, Cache_(opts.MaxSize)
{
}
inline ~TImpl() {
}
void LookupOrResolve(TContResolver& resolver, const TString& addr, ui16 port, TAddrs& result) {
TKey cacheKey(addr, port);
TEntryRef e;
auto iter = Cache_.Find(cacheKey);
if (iter == Cache_.End()) {
e = MakeIntrusive<TEntry>(Executor_);
Cache_.Insert(cacheKey, e);
} else {
e = iter.Value();
}
while (true) {
switch (e->State_) {
case RS_NOT_RESOLVED:
case RS_EXPIRED:
e->State_ = RS_IN_PROGRESS;
try {
ResolveAddr(resolver, addr, port, result);
} catch (TDnsError& err) {
e->ResolveTimestamp_ = TInstant::Now();
e->LastResolveError_ = err.AsStrBuf();
e->State_ = RS_FAILED;
e->ResolvedEvent_.BroadCast();
throw;
} catch (...) {
// errors not related to DNS
e->State_ = RS_NOT_RESOLVED;
e->ResolvedEvent_.BroadCast();
throw;
}
e->ResolveTimestamp_ = TInstant::Now();
e->Addrs_ = result;
e->State_ = RS_RESOLVED;
e->ResolvedEvent_.BroadCast();
return;
case RS_IN_PROGRESS:
e->ResolvedEvent_.WaitI();
continue;
case RS_RESOLVED:
if (e->ResolveTimestamp_ + Opts_.EntryLifetime < TInstant::Now()) {
e->State_ = RS_EXPIRED;
continue; // try and resolve again
}
result = e->Addrs_;
return;
case RS_FAILED:
if (e->ResolveTimestamp_ + Opts_.NotFoundLifetime < TInstant::Now()) {
e->State_ = RS_EXPIRED;
continue; // try and resolve again
}
ythrow TDnsError() << e->LastResolveError_;
default:
Y_FAIL("Bad state, shoult not get here");
};
}
}
private:
TContExecutor* Executor_;
const TCacheOptions Opts_;
TLRUCache<TKey, TEntryRef> Cache_;
};
TContDnsCache::TContDnsCache(TContExecutor* e, const NAsyncDns::TCacheOptions& opts)
: I_(MakeHolder<TImpl>(e, opts))
{
}
TContDnsCache::~TContDnsCache() {
}
void TContDnsCache::LookupOrResolve(TContResolver& resolver, const TString& addr, ui16 port, TVector<NAddr::IRemoteAddrRef>& result) {
return I_->LookupOrResolve(resolver, addr, port, result);
}
void TContDnsCache::LookupOrResolve(TContResolver& resolver, const TString& addr, TVector<NAddr::IRemoteAddrRef>& result) {
LookupOrResolve(resolver, addr, 80, result);
}
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