intermediate changes

ref:cde9a383711a11544ce7e107a78147fb96cc4029

1 files changed, 72 insertions, 0 deletions

diff --git a/library/cpp/http/io/compression.h b/library/cpp/http/io/compression.h
new file mode 100644
index 0000000000..f16c4a18eb
--- /dev/null
+++ b/library/cpp/http/io/compression.h
@@ -0,0 +1,72 @@
+#pragma once
+
+#include "stream.h"
+
+#include <util/generic/deque.h>
+#include <util/generic/hash.h>
+
+class TCompressionCodecFactory {
+public:
+    using TDecoderConstructor = std::function<THolder<IInputStream>(IInputStream*)>;
+    using TEncoderConstructor = std::function<THolder<IOutputStream>(IOutputStream*)>;
+
+    TCompressionCodecFactory();
+
+    static inline TCompressionCodecFactory& Instance() noexcept {
+        return *SingletonWithPriority<TCompressionCodecFactory, 0>();
+    }
+
+    inline const TDecoderConstructor* FindDecoder(TStringBuf name) const {
+        if (auto codec = Codecs_.FindPtr(name)) {
+            return &codec->Decoder;
+        }
+
+        return nullptr;
+    }
+
+    inline const TEncoderConstructor* FindEncoder(TStringBuf name) const {
+        if (auto codec = Codecs_.FindPtr(name)) {
+            return &codec->Encoder;
+        }
+
+        return nullptr;
+    }
+
+    inline TArrayRef<const TStringBuf> GetBestCodecs() const {
+        return BestCodecs_;
+    }
+
+private:
+    void Add(TStringBuf name, TDecoderConstructor d, TEncoderConstructor e);
+
+    struct TCodec {
+        TDecoderConstructor Decoder;
+        TEncoderConstructor Encoder;
+    };
+
+    TDeque<TString> Strings_;
+    THashMap<TStringBuf, TCodec> Codecs_;
+    TVector<TStringBuf> BestCodecs_;
+};
+
+namespace NHttp {
+    template <typename F>
+    TString ChooseBestCompressionScheme(F accepted, TArrayRef<const TStringBuf> available) {
+        if (available.empty()) {
+            return "identity";
+        }
+
+        if (accepted("*")) {
+            return TString(available[0]);
+        }
+
+        for (const auto& coding : available) {
+            TString s(coding);
+            if (accepted(s)) {
+                return s;
+            }
+        }
+
+        return "identity";
+    }
+}