Issue #12775 avoid unnecessary exception in getInputStream (#12789)

* Issue #12775 avoid unnecessary exception in getInputStream

Author: janbartel

jetty-core/jetty-server/src/main/java/org/eclipse/jetty/server/internal/HttpChannelState.java

@@ -917,24 +917,38 @@ public Content.Chunk read()
             try
             {
                 HttpStream stream;
+                boolean expecting100;
+                HttpChannelState httpChannel;
                 try (AutoLock ignored = _lock.lock())
                 {
-                    HttpChannelState httpChannel = lockedGetHttpChannelState();
-
+                    httpChannel = lockedGetHttpChannelState();
                     Content.Chunk error = httpChannel._readFailure;
                     httpChannel._readFailure = Content.Chunk.next(error);
                     if (error != null)
                         return error;
 
                     stream = httpChannel._stream;
+                    expecting100 = httpChannel._expects100Continue;
                 }
                 Content.Chunk chunk = stream.read();
 
                 if (LOG.isDebugEnabled())
                     LOG.debug("read {}", chunk);
 
-                if (chunk != null && chunk.hasRemaining())
-                    _contentBytesRead.add(chunk.getByteBuffer().remaining());
+                if (chunk == null)
+                    return null;
+
+                if (expecting100)
+                {
+                    // No need to send 100 continues as content has already arrived
+                    try (AutoLock ignored = _lock.lock())
+                    {
+                        httpChannel._expects100Continue = false;
+                    }
+                }
+
+                if (chunk.hasRemaining())
+                    _contentBytesRead.add(chunk.remaining());
 
                 if (chunk instanceof Trailers trailers)
                     _trailers = trailers.getTrailers();

jetty-ee10/jetty-ee10-servlet/src/main/java/org/eclipse/jetty/ee10/servlet/ServletApiRequest.java

@@ -63,6 +63,7 @@
 import org.eclipse.jetty.http.HttpField;
 import org.eclipse.jetty.http.HttpFields;
 import org.eclipse.jetty.http.HttpHeader;
+import org.eclipse.jetty.http.HttpHeaderValue;
 import org.eclipse.jetty.http.HttpStatus;
 import org.eclipse.jetty.http.HttpURI;
 import org.eclipse.jetty.http.HttpVersion;
@@ -916,9 +917,12 @@ public ServletInputStream getInputStream() throws IOException
     {
         if (_inputState != ServletContextRequest.INPUT_NONE && _inputState != ServletContextRequest.INPUT_STREAM)
             throw new IllegalStateException("READER");
+
+        // Try to write a 100 continue if it is necessary
+        if (_inputState == ServletContextRequest.INPUT_NONE && _servletContextRequest.getHeaders().contains(HttpHeader.EXPECT, HttpHeaderValue.CONTINUE.asString()))
+            _servletChannel.getResponse().writeInterim(HttpStatus.CONTINUE_100, HttpFields.EMPTY);
+
         _inputState = ServletContextRequest.INPUT_STREAM;
-        // Try to write a 100 continue, ignoring failure result if it was not necessary.
-        _servletChannel.getResponse().writeInterim(HttpStatus.CONTINUE_100, HttpFields.EMPTY);
         return getServletRequestInfo().getHttpInput();
     }
 

jetty-ee9/jetty-ee9-nested/src/main/java/org/eclipse/jetty/ee9/nested/Request.java

@@ -914,9 +914,12 @@ public ServletInputStream getInputStream() throws IOException
     {
         if (_inputState != INPUT_NONE && _inputState != INPUT_STREAM)
             throw new IllegalStateException("READER");
+
+        // Try to write a 100 continue if it is necessary.
+        if (_inputState == INPUT_NONE && _coreRequest.getHeaders().contains(HttpHeader.EXPECT, HttpHeaderValue.CONTINUE.asString()))
+            _channel.getCoreResponse().writeInterim(HttpStatus.CONTINUE_100, HttpFields.EMPTY);
+
         _inputState = INPUT_STREAM;
-        // Try to write a 100 continue, ignoring failure result if it was not necessary.
-        _channel.getCoreResponse().writeInterim(HttpStatus.CONTINUE_100, HttpFields.EMPTY);
         return _input;
     }