fix reviews on awschunking and default behavior

Author: kai-ion

src/aws-cpp-sdk-core/include/smithy/client/features/ChunkingInterceptor.h

@@ -25,22 +25,29 @@ static const size_t DATA_BUFFER_SIZE = 65536;
 
 } // anonymous namespace
 
-class AwsChunkedStreamBuf : public std::streambuf {
+class AwsChunkedStreamWrapper {
 public:
-    AwsChunkedStreamBuf(Aws::Http::HttpRequest* request, const std::shared_ptr<Aws::IOStream>& originalBody, size_t bufferSize = DATA_BUFFER_SIZE)
-        : m_request(request), m_stream(originalBody), m_data(bufferSize), m_bufferSize(bufferSize),
-          m_chunkingStream(Aws::MakeShared<Aws::StringStream>(ALLOCATION_TAG)) {
-        setg(nullptr, nullptr, nullptr);
-    }
+    AwsChunkedStreamWrapper(Aws::Http::HttpRequest* request, const std::shared_ptr<Aws::IOStream>& originalBody, size_t bufferSize = DATA_BUFFER_SIZE)
+        : m_streambuf(request, originalBody, bufferSize), m_iostream(&m_streambuf) {}
+    
+    Aws::IOStream* GetIOStream() { return &m_iostream; }
 
-protected:
-    int_type underflow() override {
-        if (gptr() < egptr()) {
-            return traits_type::to_int_type(*gptr());
+private:
+    class AwsChunkedStreamBuf : public std::streambuf {
+    public:
+        AwsChunkedStreamBuf(Aws::Http::HttpRequest* request, const std::shared_ptr<Aws::IOStream>& originalBody, size_t bufferSize)
+            : m_request(request), m_stream(originalBody), m_data(bufferSize), m_bufferSize(bufferSize),
+              m_chunkingStream(Aws::MakeShared<Aws::StringStream>(ALLOCATION_TAG)) {
+            setg(nullptr, nullptr, nullptr);
         }
-        
-        // Only read from source stream if chunking stream is empty
-        if ((m_chunkingStream->peek() == EOF || m_chunkingStream->eof()) && !m_chunkingStream->bad()) {
+
+    protected:
+        int_type underflow() override {
+            if (gptr() < egptr()) {
+                return traits_type::to_int_type(*gptr());
+            }
+            
+            // BufferedRead logic inlined per Sam's guidance
             if (m_stream->good()) {
                 m_stream->read(m_data.GetUnderlyingData(), m_bufferSize);
                 size_t bytesRead = static_cast<size_t>(m_stream->gcount());
@@ -49,23 +56,24 @@ class AwsChunkedStreamBuf : public std::streambuf {
                 if ((m_stream->peek() == EOF || m_stream->eof()) && !m_stream->bad()) {
                     writeTrailerToUnderlyingStream();
                 }
-            } else {
+            }
+            
+            if ((m_chunkingStream->peek() == EOF || m_chunkingStream->eof()) && !m_chunkingStream->bad()) {
                 return traits_type::eof();
             }
+            
+            m_chunkingStream->read(m_buffer, sizeof(m_buffer));
+            size_t bytesRead = static_cast<size_t>(m_chunkingStream->gcount());
+            if (bytesRead == 0) {
+                return traits_type::eof();
+            }
+            
+            setg(m_buffer, m_buffer, m_buffer + bytesRead);
+            return traits_type::to_int_type(*gptr());
         }
-        
-        m_chunkingStream->read(m_buffer, sizeof(m_buffer));
-        size_t bytesRead = static_cast<size_t>(m_chunkingStream->gcount());
-        if (bytesRead == 0) {
-            return traits_type::eof();
-        }
-        
-        setg(m_buffer, m_buffer, m_buffer + bytesRead);
-        return traits_type::to_int_type(*gptr());
-    }
 
-private:
-    void writeTrailerToUnderlyingStream() {
+    private:
+        void writeTrailerToUnderlyingStream() {
         Aws::StringStream chunkedTrailerStream;
         chunkedTrailerStream << "0\r\n";
         if (m_request->GetRequestHash().second != nullptr) {
@@ -95,12 +103,16 @@ class AwsChunkedStreamBuf : public std::streambuf {
         }
     }
 
-    Aws::Http::HttpRequest* m_request;
-    std::shared_ptr<Aws::IOStream> m_stream;
-    Aws::Utils::Array<char> m_data;
-    size_t m_bufferSize;
-    std::shared_ptr<Aws::IOStream> m_chunkingStream;
-    char m_buffer[8192];
+        Aws::Http::HttpRequest* m_request;
+        std::shared_ptr<Aws::IOStream> m_stream;
+        Aws::Utils::Array<char> m_data;
+        size_t m_bufferSize;
+        std::shared_ptr<Aws::IOStream> m_chunkingStream;
+        char m_buffer[8192];
+    };
+    
+    AwsChunkedStreamBuf m_streambuf;
+    Aws::IOStream m_iostream;
 };
 
 /**
@@ -148,11 +160,11 @@ class ChunkingInterceptor : public smithy::interceptor::Interceptor {
             }
         }
 
-        auto chunkedBuf = Aws::MakeUnique<AwsChunkedStreamBuf>(
+        auto wrapper = Aws::MakeShared<AwsChunkedStreamWrapper>(
             ALLOCATION_TAG, request.get(), originalBody);
         auto chunkedBody = std::shared_ptr<Aws::IOStream>(
-            new Aws::IOStream(chunkedBuf.release()));
-
+            wrapper, wrapper->GetIOStream());
+        
         request->AddContentBody(chunkedBody);
         return request;
     }