intermediate changes

ref:cde9a383711a11544ce7e107a78147fb96cc4029

1 files changed, 45 insertions, 0 deletions

diff --git a/library/cpp/dns/cache.h b/library/cpp/dns/cache.h
new file mode 100644
index 0000000000..eda5dc4070
--- /dev/null
+++ b/library/cpp/dns/cache.h
@@ -0,0 +1,45 @@
+#pragma once
+
+#include <util/network/socket.h>
+#include <util/generic/strbuf.h>
+#include <util/generic/string.h>
+
+namespace NDns {
+    struct TResolveInfo {
+        inline TResolveInfo(const TStringBuf& host, ui16 port)
+            : Host(host)
+            , Port(port)
+        {
+        }
+
+        TStringBuf Host;
+        ui16 Port;
+    };
+
+    struct TResolvedHost {
+        inline TResolvedHost(const TString& host, const TNetworkAddress& addr) noexcept
+            : Host(host)
+            , Addr(addr)
+            , Id(0)
+        {
+        }
+
+        TString Host; //resolved hostname (from TResolveInfo, - before aliasing)
+        TNetworkAddress Addr;
+        size_t Id; //cache record id
+    };
+
+    // Resolving order:
+    //   1. check local thread cache, return if found
+    //   2. check global cache, return if found
+    //   3. search alias for hostname, if found, continue resolving alias
+    //   4. normal resolver
+    const TResolvedHost* CachedResolve(const TResolveInfo& ri);
+
+    //like previous, but at stage 4 use separate thread for resolving (created on first usage)
+    //useful in green-threads with tiny stack
+    const TResolvedHost* CachedThrResolve(const TResolveInfo& ri);
+
+    //create alias for host, which can be used for static resolving (when alias is ip address)
+    void AddHostAlias(const TString& host, const TString& alias);
+}