Refine how Request / Channel / Stream completion works

jetty-core/jetty-http/src/main/java/org/eclipse/jetty/http/HttpHeader.java

@@ -14,6 +14,7 @@
 package org.eclipse.jetty.http;
 
 import java.nio.ByteBuffer;
+import java.util.EnumSet;
 
 import org.eclipse.jetty.util.Index;
 import org.eclipse.jetty.util.StringUtil;
@@ -132,6 +133,18 @@ public enum HttpHeader
     C_STATUS(":status", true),
     C_PROTOCOL(":protocol");
 
+    public static final EnumSet<HttpHeader> CONTENT_HEADERS;
+    public static final EnumSet<HttpHeader> CONTENT_HEADERS_304;
+
+    static
+    {
+        CONTENT_HEADERS = EnumSet.of(
+            CONTENT_TYPE, CONTENT_LENGTH, CONTENT_ENCODING, CONTENT_LANGUAGE, CONTENT_RANGE, CONTENT_MD5, CONTENT_LOCATION, TRANSFER_ENCODING, CACHE_CONTROL, LAST_MODIFIED, EXPIRES, VARY, ETAG
+        );
+        CONTENT_HEADERS_304 = EnumSet.copyOf(CONTENT_HEADERS);
+        CONTENT_HEADERS_304.remove(ETAG);
+    }
+
     public static final Index<HttpHeader> CACHE = new Index.Builder<HttpHeader>()
         .caseSensitive(false)
         .withAll(HttpHeader.values(), HttpHeader::toString)

jetty-core/jetty-http2/jetty-http2-tests/src/test/java/org/eclipse/jetty/http2/tests/StreamResetTest.java

@@ -556,7 +556,7 @@ public void succeeded()
         });
 
         // Wait for WINDOW_UPDATEs to be processed by the client.
-        await().atMost(1000, TimeUnit.SECONDS).until(() -> ((HTTP2Session)client).updateSendWindow(0), Matchers.greaterThan(0));
+        await().atMost(5, TimeUnit.SECONDS).until(() -> ((HTTP2Session)client).updateSendWindow(0), Matchers.greaterThan(0));
 
         latch.set(new CountDownLatch(2 * streams.size()));
         // Notify all blocked threads to wakeup.

jetty-core/jetty-server/src/main/java/org/eclipse/jetty/server/Request.java

@@ -250,7 +250,7 @@ default void push(MetaData.Request resource)
     /**
      * <p>Adds a listener for asynchronous errors.</p>
      * <p>The listener is a predicate function that should return {@code true} to indicate
-     * that the function has completed (either successfully or with a failure) the callback
+     * that the function will complete (either successfully or with a failure) the callback
      * received from {@link org.eclipse.jetty.server.Handler#handle(Request, Response, Callback)}, or
      * {@code false} otherwise.</p>
      * <p>Listeners are processed in sequence, and the first that returns {@code true}

jetty-core/jetty-server/src/main/java/org/eclipse/jetty/server/handler/ErrorHandler.java

@@ -41,6 +41,7 @@
 import org.eclipse.jetty.http.QuotedQualityCSV;
 import org.eclipse.jetty.io.ByteBufferOutputStream;
 import org.eclipse.jetty.io.Content;
+import org.eclipse.jetty.io.Retainable;
 import org.eclipse.jetty.io.RetainableByteBuffer;
 import org.eclipse.jetty.server.Request;
 import org.eclipse.jetty.server.Response;
@@ -86,6 +87,8 @@ public boolean errorPageForMethod(String method)
     @Override
     public boolean handle(Request request, Response response, Callback callback)
     {
+        if (LOG.isDebugEnabled())
+            LOG.debug("handle({}, {}, {})", request, response, callback);
         if (_cacheControl != null)
             response.getHeaders().put(_cacheControl);
 
@@ -256,22 +259,7 @@ else if (charsets.contains(StandardCharsets.ISO_8859_1))
             }
 
             response.getHeaders().put(type.getContentTypeField(charset));
-            response.write(true, buffer.getByteBuffer(), new Callback.Nested(callback)
-            {
-                @Override
-                public void succeeded()
-                {
-                    buffer.release();
-                    super.succeeded();
-                }
-
-                @Override
-                public void failed(Throwable x)
-                {
-                    buffer.release();
-                    super.failed(x);
-                }
-            });
+            response.write(true, buffer.getByteBuffer(), new WriteErrorCallback(callback, buffer));
 
             return true;
         }
@@ -576,5 +564,34 @@ public Set<String> getAttributeNameSet()
                 names.add(ERROR_EXCEPTION);
             return names;
         }
+
+        @Override
+        public String toString()
+        {
+            return "%s@%x:%s".formatted(getClass().getSimpleName(), hashCode(), getWrapped());
+        }
+    }
+
+    /**
+     * The callback used by
+     * {@link ErrorHandler#generateAcceptableResponse(Request, Response, Callback, String, List, int, String, Throwable)}
+     * when calling {@link Response#write(boolean, ByteBuffer, Callback)} to wrap the passed in {@link Callback}
+     * so that the {@link RetainableByteBuffer} used can be released.
+     */
+    private static class WriteErrorCallback extends Callback.Nested
+    {
+        private final Retainable _retainable;
+
+        public WriteErrorCallback(Callback callback, Retainable retainable)
+        {
+            super(callback);
+            _retainable = retainable;
+        }
+
+        @Override
+        public void completed()
+        {
+            _retainable.release();
+        }
     }
 }