diff --git a/platform/built-in-server/src/org/jetbrains/io/fastCgi/FastCgiDecoder.kt b/platform/built-in-server/src/org/jetbrains/io/fastCgi/FastCgiDecoder.kt
index 60f320e6fec2..64e295b03f65 100644
--- a/platform/built-in-server/src/org/jetbrains/io/fastCgi/FastCgiDecoder.kt
+++ b/platform/built-in-server/src/org/jetbrains/io/fastCgi/FastCgiDecoder.kt
@@ -10,13 +10,13 @@ import org.jetbrains.io.Decoder
 
 internal const val HEADER_LENGTH = 8
 
-internal class FastCgiDecoder(private val errorOutputConsumer: Consumer<String>, private val responseHandler: FastCgiService) : Decoder(), Decoder.FullMessageConsumer<Void> {
-  private enum class State {
-    HEADER,
-    CONTENT
-  }
+private enum class DecodeRecordState {
+  HEADER,
+  CONTENT
+}
 
-  private var state = State.HEADER
+internal class FastCgiDecoder(private val errorOutputConsumer: Consumer<String>, private val responseHandler: FastCgiService) : Decoder(), Decoder.FullMessageConsumer<Void> {
+  private var state = DecodeRecordState.HEADER
 
   private enum class ProtocolStatus {
     REQUEST_COMPLETE,
@@ -31,8 +31,8 @@ internal class FastCgiDecoder(private val errorOutputConsumer: Consumer<String>,
     val STDERR = 7
   }
 
-  private var type: Int = 0
-  private var id: Int = 0
+  private var type = 0
+  private var id = 0
   private var contentLength: Int = 0
   private var paddingLength: Int = 0
 
@@ -41,7 +41,7 @@ internal class FastCgiDecoder(private val errorOutputConsumer: Consumer<String>,
   override fun messageReceived(context: ChannelHandlerContext, input: ByteBuf) {
     while (true) {
       when (state) {
-        FastCgiDecoder.State.HEADER -> {
+        DecodeRecordState.HEADER -> {
           if (paddingLength > 0) {
             if (input.readableBytes() > paddingLength) {
               input.skipBytes(paddingLength)
@@ -55,21 +55,20 @@ internal class FastCgiDecoder(private val errorOutputConsumer: Consumer<String>,
           }
 
           val buffer = getBufferIfSufficient(input, HEADER_LENGTH, context) ?: return
-
-          decodeHeader(buffer)
-          state = State.CONTENT
-
-          if (contentLength > 0) {
-            readContent(input, context, contentLength, this)
-          }
-          state = State.HEADER
+          buffer.skipBytes(1)
+          type = buffer.readUnsignedByte().toInt()
+          id = buffer.readUnsignedShort()
+          contentLength = buffer.readUnsignedShort()
+          paddingLength = buffer.readUnsignedByte().toInt()
+          buffer.skipBytes(1)
+          state = DecodeRecordState.CONTENT
         }
 
-        FastCgiDecoder.State.CONTENT -> {
+        DecodeRecordState.CONTENT -> {
           if (contentLength > 0) {
             readContent(input, context, contentLength, this)
           }
-          state = State.HEADER
+          state = DecodeRecordState.HEADER
         }
       }
     }
@@ -95,52 +94,30 @@ internal class FastCgiDecoder(private val errorOutputConsumer: Consumer<String>,
     }
   }
 
-  private fun decodeHeader(buffer: ByteBuf) {
-    buffer.skipBytes(1)
-    type = buffer.readUnsignedByte().toInt()
-    id = buffer.readUnsignedShort()
-    contentLength = buffer.readUnsignedShort()
-    paddingLength = buffer.readUnsignedByte().toInt()
-    buffer.skipBytes(1)
-  }
-
   override fun contentReceived(buffer: ByteBuf, context: ChannelHandlerContext, isCumulateBuffer: Boolean): Void? {
     when (type) {
-      RecordType.END_REQUEST -> {
-        val appStatus = buffer.readInt()
-        val protocolStatus = buffer.readUnsignedByte().toInt()
-        if (appStatus != 0 || protocolStatus != ProtocolStatus.REQUEST_COMPLETE.ordinal) {
-          LOG.warn("Protocol status $protocolStatus")
-          dataBuffers.remove(id)
-          responseHandler.responseReceived(id, null)
-        }
-        else if (protocolStatus == ProtocolStatus.REQUEST_COMPLETE.ordinal) {
-          responseHandler.responseReceived(id, dataBuffers.remove(id))
-        }
-      }
-
       RecordType.STDOUT -> {
         var data = dataBuffers.get(id)
         val sliced = if (isCumulateBuffer) buffer else buffer.slice(buffer.readerIndex(), contentLength)
-        if (data == null) {
-          dataBuffers.put(id, sliced)
-        }
-        else if (data is CompositeByteBuf) {
-          data.addComponent(sliced)
-          data.writerIndex(data.writerIndex() + sliced.readableBytes())
-        }
-        else {
-          if (sliced is CompositeByteBuf) {
-            data = sliced.addComponent(0, data)
-            data.writerIndex(data.writerIndex() + data.readableBytes())
+        when (data) {
+          null -> dataBuffers.put(id, sliced)
+          is CompositeByteBuf -> {
+            data.addComponent(sliced)
+            data.writerIndex(data.writerIndex() + sliced.readableBytes())
           }
-          else {
-            // must be computed here before we set data to new composite buffer
-            val newLength = data.readableBytes() + sliced.readableBytes()
-            data = context.alloc().compositeBuffer(Decoder.DEFAULT_MAX_COMPOSITE_BUFFER_COMPONENTS).addComponents(data, sliced)
-            data.writerIndex(data.writerIndex() + newLength)
+          else -> {
+            if (sliced is CompositeByteBuf) {
+              data = sliced.addComponent(0, data)
+              data.writerIndex(data.writerIndex() + data.readableBytes())
+            }
+            else {
+              // must be computed here before we set data to new composite buffer
+              val newLength = data.readableBytes() + sliced.readableBytes()
+              data = context.alloc().compositeBuffer(Decoder.DEFAULT_MAX_COMPOSITE_BUFFER_COMPONENTS).addComponents(data, sliced)
+              data.writerIndex(data.writerIndex() + newLength)
+            }
+            dataBuffers.put(id, data)
           }
-          dataBuffers.put(id, data)
         }
         sliced.retain()
       }
@@ -154,7 +131,25 @@ internal class FastCgiDecoder(private val errorOutputConsumer: Consumer<String>,
         }
       }
 
-      else -> LOG.error("Unknown type $type")
+      RecordType.END_REQUEST -> {
+        val appStatus = buffer.readInt()
+        val protocolStatus = buffer.readUnsignedByte().toInt()
+        if (appStatus != 0 || protocolStatus != ProtocolStatus.REQUEST_COMPLETE.ordinal) {
+          LOG.warn("Protocol status $protocolStatus")
+          dataBuffers.remove(id)
+          responseHandler.responseReceived(id, null)
+        }
+        else if (protocolStatus == ProtocolStatus.REQUEST_COMPLETE.ordinal) {
+          responseHandler.responseReceived(id, dataBuffers.remove(id))
+        }
+        else {
+          LOG.warn("protocolStatus $protocolStatus")
+        }
+      }
+
+      else -> {
+        LOG.error("Unknown type $type")
+      }
     }
     return null
   }