Freeze HttpFields

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

@@ -1582,6 +1582,13 @@ public Mutable add(HttpField field)
                 return this;
             }
 
+            @Override
+            public Mutable clear()
+            {
+                _fields.clear();
+                return this;
+            }
+
             @Override
             public ListIterator<HttpField> listIterator()
             {

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

@@ -46,11 +46,6 @@ public class HttpGenerator
 
     private static final byte[] __colon_space = new byte[]{':', ' '};
     public static final MetaData.Response CONTINUE_100_INFO = new MetaData.Response(100, null, HttpVersion.HTTP_1_1, HttpFields.EMPTY);
-    public static final MetaData.Response PROGRESS_102_INFO = new MetaData.Response(102, null, HttpVersion.HTTP_1_1, HttpFields.EMPTY);
-    public static final MetaData.Response RESPONSE_400_INFO =
-        new MetaData.Response(HttpStatus.BAD_REQUEST_400, null, HttpVersion.HTTP_1_1, HttpFields.build().add(HttpFields.CONNECTION_CLOSE), 0);
-    public static final MetaData.Response RESPONSE_500_INFO =
-        new MetaData.Response(INTERNAL_SERVER_ERROR_500, null, HttpVersion.HTTP_1_1, HttpFields.build().add(HttpFields.CONNECTION_CLOSE), 0);
 
     // states
     public enum State
@@ -808,12 +803,6 @@ public String toString()
     private static final byte[] CONNECTION_CLOSE = StringUtil.getBytes("Connection: close\r\n");
     private static final byte[] HTTP_1_1_SPACE = StringUtil.getBytes(HttpVersion.HTTP_1_1 + " ");
     private static final byte[] TRANSFER_ENCODING_CHUNKED = StringUtil.getBytes("Transfer-Encoding: chunked\r\n");
-    private static final byte[][] SEND = new byte[][]{
-        new byte[0],
-        StringUtil.getBytes("Server: Jetty(12.x.x)\r\n"),
-        StringUtil.getBytes("X-Powered-By: Jetty(12.x.x)\r\n"),
-        StringUtil.getBytes("Server: Jetty(12.x.x)\r\nX-Powered-By: Jetty(12.x.x)\r\n")
-    };
 
     // Build cache of response lines for status
     private static class PreparedResponse

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

@@ -33,12 +33,12 @@
 import org.eclipse.jetty.http.HttpField;
 import org.eclipse.jetty.http.HttpHeader;
 import org.eclipse.jetty.http.MimeTypes;
-import org.eclipse.jetty.http.PreEncodedHttpField;
 import org.eclipse.jetty.io.ArrayByteBufferPool;
 import org.eclipse.jetty.io.ByteBufferPool;
 import org.eclipse.jetty.io.Connection;
 import org.eclipse.jetty.server.handler.ContextHandler;
 import org.eclipse.jetty.server.handler.ErrorHandler;
+import org.eclipse.jetty.server.internal.ResponseHttpFields;
 import org.eclipse.jetty.util.Attributes;
 import org.eclipse.jetty.util.Callback;
 import org.eclipse.jetty.util.DecoratedObjectFactory;
@@ -474,6 +474,11 @@ public void setDumpBeforeStop(boolean dumpBeforeStop)
         _dumpBeforeStop = dumpBeforeStop;
     }
 
+    /**
+     * @return A {@link HttpField} instance efficiently recording the current time to a second resolution,
+     * that cannot be cleared from a {@link ResponseHttpFields} instance.
+     * @see ResponseHttpFields.PersistentPreEncodedHttpField
+     */
     public HttpField getDateField()
     {
         long now = System.currentTimeMillis();
@@ -487,7 +492,7 @@ public HttpField getDateField()
                 df = _dateField;
                 if (df == null || df._seconds != seconds)
                 {
-                    HttpField field = new PreEncodedHttpField(HttpHeader.DATE, DateGenerator.formatDate(now));
+                    HttpField field = new ResponseHttpFields.PersistentPreEncodedHttpField(HttpHeader.DATE, DateGenerator.formatDate(now));
                     _dateField = new DateField(seconds, field);
                     return field;
                 }

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

@@ -37,7 +37,6 @@
 import org.eclipse.jetty.http.HttpVersion;
 import org.eclipse.jetty.http.MetaData;
 import org.eclipse.jetty.http.MultiPartFormData.Parts;
-import org.eclipse.jetty.http.PreEncodedHttpField;
 import org.eclipse.jetty.http.Trailers;
 import org.eclipse.jetty.http.UriCompliance;
 import org.eclipse.jetty.io.ByteBufferPool;
@@ -97,8 +96,8 @@ private enum StreamSendState
 
     private static final Logger LOG = LoggerFactory.getLogger(HttpChannelState.class);
     private static final Throwable DO_NOT_SEND = new Throwable("No Send");
-    private static final HttpField SERVER_VERSION = new PreEncodedHttpField(HttpHeader.SERVER, HttpConfiguration.SERVER_VERSION);
-    private static final HttpField POWERED_BY = new PreEncodedHttpField(HttpHeader.X_POWERED_BY, HttpConfiguration.SERVER_VERSION);
+    private static final HttpField SERVER_VERSION = new ResponseHttpFields.PersistentPreEncodedHttpField(HttpHeader.SERVER, HttpConfiguration.SERVER_VERSION);
+    private static final HttpField POWERED_BY = new ResponseHttpFields.PersistentPreEncodedHttpField(HttpHeader.X_POWERED_BY, HttpConfiguration.SERVER_VERSION);
 
     private final AutoLock _lock = new AutoLock();
     private final HandlerInvoker _handlerInvoker = new HandlerInvoker();
@@ -273,8 +272,8 @@ public Runnable onRequest(MetaData.Request request)
             _request = new ChannelRequest(this, request);
             _response = new ChannelResponse(_request);
 
-            HttpFields.Mutable responseHeaders = _response.getHeaders();
             HttpConfiguration httpConfiguration = getHttpConfiguration();
+            HttpFields.Mutable responseHeaders = _response.getHeaders();
             if (httpConfiguration.getSendServerVersion())
                 responseHeaders.add(SERVER_VERSION);
             if (httpConfiguration.getSendXPoweredBy())

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

@@ -20,9 +20,13 @@
 
 import org.eclipse.jetty.http.HttpField;
 import org.eclipse.jetty.http.HttpFields;
+import org.eclipse.jetty.http.HttpHeader;
+import org.eclipse.jetty.http.PreEncodedHttpField;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
+import static org.eclipse.jetty.server.internal.ResponseHttpFields.PersistentField.isPersistent;
+
 public class ResponseHttpFields implements HttpFields.Mutable
 {
     private static final Logger LOG = LoggerFactory.getLogger(ResponseHttpFields.class);
@@ -88,7 +92,17 @@ public HttpFields asImmutable()
     @Override
     public Mutable clear()
     {
-        return _committed.get() ? this : _fields.clear();
+        if (!_committed.get())
+        {
+            // TODO iterate backwards when the list iterator of that form is available
+            for (Iterator<HttpField> iterator = _fields.iterator(); iterator.hasNext();)
+            {
+                HttpField field = iterator.next();
+                if (!PersistentField.isPersistent(field))
+                    iterator.remove();
+            }
+        }
+        return this;
     }
 
     @Override
@@ -104,6 +118,8 @@ public Iterator<HttpField> iterator()
         Iterator<HttpField> i = _fields.iterator();
         return new Iterator<>()
         {
+            HttpField _current;
+
             @Override
             public boolean hasNext()
             {
@@ -113,15 +129,19 @@ public boolean hasNext()
             @Override
             public HttpField next()
             {
-                return i.next();
+                _current = i.next();
+                return _current;
             }
 
             @Override
             public void remove()
             {
                 if (_committed.get())
                     throw new UnsupportedOperationException("Read Only");
+                if (isPersistent(_current))
+                    throw new IllegalStateException("Persistent field");
                 i.remove();
+                _current = null;
             }
         };
     }
@@ -132,6 +152,8 @@ public ListIterator<HttpField> listIterator()
         ListIterator<HttpField> i = _fields.listIterator();
         return new ListIterator<>()
         {
+            HttpField _current;
+
             @Override
             public boolean hasNext()
             {
@@ -141,7 +163,8 @@ public boolean hasNext()
             @Override
             public HttpField next()
             {
-                return i.next();
+                _current = i.next();
+                return _current;
             }
 
             @Override
@@ -153,7 +176,8 @@ public boolean hasPrevious()
             @Override
             public HttpField previous()
             {
-                return i.previous();
+                _current = i.previous();
+                return _current;
             }
 
             @Override
@@ -173,18 +197,34 @@ public void remove()
             {
                 if (_committed.get())
                     throw new UnsupportedOperationException("Read Only");
+                if (isPersistent(_current))
+                    throw new IllegalStateException("Persistent field");
                 i.remove();
+                _current = null;
             }
 
             @Override
             public void set(HttpField field)
             {
                 if (_committed.get())
                     throw new UnsupportedOperationException("Read Only");
+                if (isPersistent(_current))
+                {
+                    // cannot change the field name
+                    if (field == null || !field.isSameName(_current))
+                        throw new IllegalStateException("Persistent field");
+
+                    // new field must also be persistent
+                    if (!isPersistent(field))
+                        field = (field instanceof PreEncodedHttpField)
+                            ? new PersistentPreEncodedHttpField(field.getHeader(), field.getValue())
+                            : new PersistentHttpField(field);
+                }
                 if (field == null)
                     i.remove();
                 else
                     i.set(field);
+                _current = field;
             }
 
             @Override
@@ -203,4 +243,59 @@ public String toString()
     {
         return _fields.toString();
     }
+
+    /**
+     * A marker interface for {@link HttpField}s that cannot be {@link #remove(HttpHeader) removed} or {@link #clear() cleared}
+     * from a {@link ResponseHttpFields} instance.   Persistent fields are not immutable in the {@link ResponseHttpFields}
+     * and may be replaced with a different value.
+     */
+    public interface PersistentField
+    {
+        static boolean isPersistent(HttpField field)
+        {
+            return field instanceof PersistentField;
+        }
+    }
+
+    /**
+     * A {@link HttpField} that is a {@link PersistentField}.
+     */
+    public static class PersistentHttpField extends HttpField implements PersistentField
+    {
+        private final HttpField _field;
+
+        public PersistentHttpField(HttpField field)
+        {
+            super(field.getHeader(), field.getName(), field.getValue());
+            _field = field;
+        }
+
+        @Override
+        public int getIntValue()
+        {
+            return _field.getIntValue();
+        }
+
+        @Override
+        public long getLongValue()
+        {
+            return _field.getIntValue();
+        }
+    }
+
+    /**
+     * A {@link PreEncodedHttpField} that is a {@link PersistentField}.
+     */
+    public static class PersistentPreEncodedHttpField extends PreEncodedHttpField implements PersistentField
+    {
+        public PersistentPreEncodedHttpField(HttpHeader header, String value)
+        {
+            this(header, value, true);
+        }
+
+        public PersistentPreEncodedHttpField(HttpHeader header, String value, boolean immutable)
+        {
+            super(header, value);
+        }
+    }
 }