Issue #11080 - copy ByteBuffer for non-retainable chunks

Signed-off-by: Lachlan Roberts <lachlan@webtide.com>

jetty-core/jetty-http/src/test/java/org/eclipse/jetty/http/MultiPartFormDataTest.java

@@ -13,6 +13,7 @@
 
 package org.eclipse.jetty.http;
 
+import java.io.ByteArrayInputStream;
 import java.io.IOException;
 import java.nio.ByteBuffer;
 import java.nio.charset.Charset;
@@ -27,6 +28,7 @@ import java.util.concurrent.atomic.AtomicInteger;
 
 import org.eclipse.jetty.io.Content;
 import org.eclipse.jetty.io.content.AsyncContent;
+import org.eclipse.jetty.io.content.InputStreamContentSource;
 import org.eclipse.jetty.toolchain.test.FS;
 import org.eclipse.jetty.toolchain.test.MavenTestingUtils;
 import org.eclipse.jetty.util.BufferUtil;
@@ -934,6 +936,48 @@ public class MultiPartFormDataTest
         assertInstanceOf(IllegalArgumentException.class, cause);
     }
 
+    @Test
+    public void testNonRetainableContent() throws Exception
+    {
+        String body = """
+            --AaB03x\r
+            content-disposition: form-data; name="field1"\r
+            \r
+            Joe Blow\r
+            --AaB03x\r
+            content-disposition: form-data; name="stuff"; filename="foo.txt"\r
+            Content-Type: text/plain\r
+            \r
+            aaaabbbbb\r
+            --AaB03x--\r
+            """;
+
+        Content.Source source = new InputStreamContentSource(new ByteArrayInputStream(body.getBytes(ISO_8859_1)))
+        {
+            @Override
+            public Content.Chunk read()
+            {
+                Content.Chunk chunk = super.read();
+                return new NonRetainableChunk(chunk);
+            }
+        };
+
+        MultiPartFormData.Parser formData = new MultiPartFormData.Parser("AaB03x");
+        formData.setFilesDirectory(_tmpDir);
+        try (MultiPartFormData.Parts parts = formData.parse(source).get(5, TimeUnit.SECONDS))
+        {
+            assertThat(parts.size(), is(2));
+            MultiPart.Part part1 = parts.getFirst("field1");
+            assertThat(part1, notNullValue());
+            Content.Source partContent = part1.getContentSource();
+            assertThat(Content.Source.asString(partContent), is("Joe Blow"));
+            MultiPart.Part part2 = parts.getFirst("stuff");
+            assertThat(part2, notNullValue());
+            partContent = part2.getContentSource();
+            assertThat(Content.Source.asString(partContent), is("aaaabbbbb"));
+        }
+    }
+
     private class TestContent extends AsyncContent
     {
         @Override
@@ -945,4 +989,43 @@ public class MultiPartFormDataTest
             return chunk;
         }
     }
+
+    private static class NonRetainableChunk implements Content.Chunk
+    {
+        private final ByteBuffer _content;
+        private final boolean _isLast;
+        private final Throwable _failure;
+
+        public NonRetainableChunk(Content.Chunk chunk)
+        {
+            _content = BufferUtil.copy(chunk.getByteBuffer());
+            _isLast = chunk.isLast();
+            _failure = chunk.getFailure();
+            chunk.release();
+        }
+
+        @Override
+        public ByteBuffer getByteBuffer()
+        {
+            return _content;
+        }
+
+        @Override
+        public boolean isLast()
+        {
+            return _isLast;
+        }
+
+        @Override
+        public Throwable getFailure()
+        {
+            return _failure;
+        }
+
+        @Override
+        public void retain()
+        {
+            throw new UnsupportedOperationException();
+        }
+    }
 }

jetty-core/jetty-io/src/main/java/org/eclipse/jetty/io/Content.java

@@ -41,6 +41,8 @@ import org.eclipse.jetty.util.FutureCallback;
 import org.eclipse.jetty.util.FuturePromise;
 import org.eclipse.jetty.util.IO;
 import org.eclipse.jetty.util.Promise;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 /**
  * <p>Namespace class that contains the definitions of a {@link Source content source},
@@ -48,6 +50,8 @@ import org.eclipse.jetty.util.Promise;
  */
 public class Content
 {
+    private static final Logger LOG = LoggerFactory.getLogger(Content.class);
+
     private Content()
     {
     }
@@ -666,15 +670,22 @@ public class Content
          * @param last whether the Chunk is the last one
          * @param retainable the Retainable this Chunk links to
          * @return a new Chunk
-         * @throws IllegalArgumentException if the {@code Retainable}
-         * {@link Retainable#canRetain() cannot be retained}
          */
         static Chunk asChunk(ByteBuffer byteBuffer, boolean last, Retainable retainable)
         {
-            if (!retainable.canRetain())
-                throw new IllegalArgumentException("Cannot create chunk from non-retainable " + retainable);
             if (byteBuffer.hasRemaining())
-                return new ByteBufferChunk.WithRetainable(byteBuffer, last, Objects.requireNonNull(retainable));
+            {
+                if (retainable.canRetain())
+                {
+                    return new ByteBufferChunk.WithRetainable(byteBuffer, last, Objects.requireNonNull(retainable));
+                }
+                else
+                {
+                    if (LOG.isDebugEnabled())
+                        LOG.debug("Copying buffer because could not retain");
+                    return new ByteBufferChunk.WithReferenceCount(BufferUtil.copy(byteBuffer), last);
+                }
+            }
             retainable.release();
             return last ? EOF : EMPTY;
         }