Decouple more classes from XContentBuilder and make builder strict (#29197)

This commit decouples `BytesRef`, `Releaseable`, and `TimeValue` from
XContentBuilder, and paves the way for doupling `ByteSizeValue` as well. It
moves much of the Lucene and Joda encoding into a new SPI extension that is
loaded by XContentBuilder to know how to encode these values.

Part of doing this also allows us to make JSON encoding strict, as we no longer
allow just any old object to be passed (in the past it was possible to get json
that was `"field": "java.lang.Object@d8355a8"` if no one was careful about what
was passed in).

Relates to #28504

Author: dakrone

server/src/main/java/org/elasticsearch/Version.java

@@ -25,6 +25,8 @@
 import org.elasticsearch.common.io.stream.StreamInput;
 import org.elasticsearch.common.io.stream.StreamOutput;
 import org.elasticsearch.common.settings.Settings;
+import org.elasticsearch.common.xcontent.ToXContentFragment;
+import org.elasticsearch.common.xcontent.XContentBuilder;
 import org.elasticsearch.monitor.jvm.JvmInfo;
 
 import java.io.IOException;
@@ -34,7 +36,7 @@
 import java.util.Collections;
 import java.util.List;
 
-public class Version implements Comparable<Version> {
+public class Version implements Comparable<Version>, ToXContentFragment {
     /*
      * The logic for ID is: XXYYZZAA, where XX is major version, YY is minor version, ZZ is revision, and AA is alpha/beta/rc indicator AA
      * values below 25 are for alpha builder (since 5.0), and above 25 and below 50 are beta builds, and below 99 are RC builds, with 99
@@ -409,6 +411,11 @@ public int compareTo(Version other) {
         return Integer.compare(this.id, other.id);
     }
 
+    @Override
+    public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
+        return builder.value(toString());
+    }
+
     /*
      * We need the declared versions when computing the minimum compatibility version. As computing the declared versions uses reflection it
      * is not cheap. Since computing the minimum compatibility version can occur often, we use this holder to compute the declared versions

server/src/main/java/org/elasticsearch/common/bytes/BytesReference.java

@@ -23,6 +23,7 @@
 import org.apache.lucene.util.BytesRefIterator;
 import org.elasticsearch.common.io.stream.BytesStream;
 import org.elasticsearch.common.io.stream.StreamInput;
+import org.elasticsearch.common.xcontent.ToXContentFragment;
 import org.elasticsearch.common.xcontent.XContentBuilder;
 
 import java.io.ByteArrayOutputStream;
@@ -35,7 +36,7 @@
 /**
  * A reference to bytes.
  */
-public abstract class BytesReference implements Accountable, Comparable<BytesReference> {
+public abstract class BytesReference implements Accountable, Comparable<BytesReference>, ToXContentFragment {
 
     private Integer hash = null; // we cache the hash of this reference since it can be quite costly to re-calculated it
 
@@ -301,4 +302,10 @@ public long skip(long n) throws IOException {
             return input.skip(n);
         }
     }
+
+    @Override
+    public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
+        BytesRef bytes = toBytesRef();
+        return builder.value(bytes.bytes, bytes.offset, bytes.length);
+    }
 }

server/src/main/java/org/elasticsearch/common/document/DocumentField.java

@@ -19,6 +19,7 @@
 
 package org.elasticsearch.common.document;
 
+import org.apache.lucene.util.BytesRef;
 import org.elasticsearch.common.bytes.BytesReference;
 import org.elasticsearch.common.io.stream.StreamInput;
 import org.elasticsearch.common.io.stream.StreamOutput;
@@ -127,11 +128,7 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
             // Stored fields values are converted using MappedFieldType#valueForDisplay.
             // As a result they can either be Strings, Numbers, or Booleans, that's
             // all.
-            if (value instanceof BytesReference) {
-                builder.binaryValue(((BytesReference) value).toBytesRef());
-            } else {
-                builder.value(value);
-            }
+            builder.value(value);
         }
         builder.endArray();
         return builder;

server/src/main/java/org/elasticsearch/common/text/Text.java

@@ -18,6 +18,7 @@
  */
 package org.elasticsearch.common.text;
 
+import org.apache.lucene.util.BytesRef;
 import org.elasticsearch.common.bytes.BytesArray;
 import org.elasticsearch.common.bytes.BytesReference;
 import org.elasticsearch.common.xcontent.ToXContent;
@@ -125,7 +126,8 @@ public XContentBuilder toXContent(XContentBuilder builder, Params params) throws
         } else {
             // TODO: TextBytesOptimization we can use a buffer here to convert it? maybe add a
             // request to jackson to support InputStream as well?
-            return builder.utf8Value(this.bytes().toBytesRef());
+            BytesRef br = this.bytes().toBytesRef();
+            return builder.utf8Value(br.bytes, br.offset, br.length);
         }
     }
 }

server/src/main/java/org/elasticsearch/common/transport/TransportAddress.java

@@ -25,6 +25,9 @@
 import org.elasticsearch.common.io.stream.StreamOutput;
 import org.elasticsearch.common.io.stream.Writeable;
 import org.elasticsearch.common.network.NetworkAddress;
+import org.elasticsearch.common.xcontent.ToXContent;
+import org.elasticsearch.common.xcontent.ToXContentFragment;
+import org.elasticsearch.common.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.net.InetAddress;
@@ -34,7 +37,7 @@
 /**
  * A transport address used for IP socket address (wraps {@link java.net.InetSocketAddress}).
  */
-public final class TransportAddress implements Writeable {
+public final class TransportAddress implements Writeable, ToXContentFragment {
 
     /**
      * A <a href="https://en.wikipedia.org/wiki/0.0.0.0">non-routeable v4 meta transport address</a> that can be used for
@@ -155,4 +158,9 @@ public int hashCode() {
     public String toString() {
         return NetworkAddress.format(address);
     }
+
+    @Override
+    public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
+        return builder.value(toString());
+    }
 }

server/src/main/java/org/elasticsearch/common/unit/ByteSizeValue.java

@@ -27,12 +27,15 @@
 import org.elasticsearch.common.io.stream.Writeable;
 import org.elasticsearch.common.logging.DeprecationLogger;
 import org.elasticsearch.common.logging.Loggers;
+import org.elasticsearch.common.xcontent.ToXContent;
+import org.elasticsearch.common.xcontent.ToXContentFragment;
+import org.elasticsearch.common.xcontent.XContentBuilder;
 
 import java.io.IOException;
 import java.util.Locale;
 import java.util.Objects;
 
-public class ByteSizeValue implements Writeable, Comparable<ByteSizeValue> {
+public class ByteSizeValue implements Writeable, Comparable<ByteSizeValue>, ToXContentFragment {
     private static final DeprecationLogger DEPRECATION_LOGGER = new DeprecationLogger(Loggers.getLogger(ByteSizeValue.class));
 
     private final long size;
@@ -271,4 +274,9 @@ public int compareTo(ByteSizeValue other) {
         long otherValue = other.size * other.unit.toBytes(1);
         return Long.compare(thisValue, otherValue);
     }
+
+    @Override
+    public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
+        return builder.value(toString());
+    }
 }

server/src/main/java/org/elasticsearch/common/unit/TimeValue.java

@@ -24,6 +24,9 @@
 import org.elasticsearch.common.io.stream.StreamInput;
 import org.elasticsearch.common.io.stream.StreamOutput;
 import org.elasticsearch.common.io.stream.Writeable;
+import org.elasticsearch.common.xcontent.ToXContent;
+import org.elasticsearch.common.xcontent.ToXContentFragment;
+import org.elasticsearch.common.xcontent.XContentBuilder;
 import org.joda.time.Period;
 import org.joda.time.PeriodType;
 import org.joda.time.format.PeriodFormat;
@@ -40,7 +43,7 @@
 import java.util.Set;
 import java.util.concurrent.TimeUnit;
 
-public class TimeValue implements Writeable, Comparable<TimeValue> {
+public class TimeValue implements Writeable, Comparable<TimeValue>, ToXContentFragment {
 
     /** How many nano-seconds in one milli-second */
     public static final long NSEC_PER_MSEC = TimeUnit.NANOSECONDS.convert(1, TimeUnit.MILLISECONDS);
@@ -398,4 +401,9 @@ public int compareTo(TimeValue timeValue) {
         double otherValue = ((double) timeValue.duration) * timeValue.timeUnit.toNanos(1);
         return Double.compare(thisValue, otherValue);
     }
+
+    @Override
+    public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
+        return builder.value(toString());
+    }
 }

server/src/main/java/org/elasticsearch/common/xcontent/XContentBuilder.java

@@ -19,22 +19,21 @@
 
 package org.elasticsearch.common.xcontent;
 
-import org.apache.lucene.util.BytesRef;
-import org.elasticsearch.common.lease.Releasable;
 import org.elasticsearch.common.unit.ByteSizeValue;
-import org.elasticsearch.common.unit.TimeValue;
 import org.elasticsearch.common.util.CollectionUtils;
 import org.joda.time.DateTimeZone;
 import org.joda.time.ReadableInstant;
 import org.joda.time.format.DateTimeFormatter;
 import org.joda.time.format.ISODateTimeFormat;
 
 import java.io.ByteArrayOutputStream;
+import java.io.Closeable;
 import java.io.Flushable;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
 import java.nio.file.Path;
+import java.time.ZonedDateTime;
 import java.util.Arrays;
 import java.util.Calendar;
 import java.util.Collections;
@@ -49,7 +48,7 @@
 /**
  * A utility to build XContent (ie json).
  */
-public final class XContentBuilder implements Releasable, Flushable {
+public final class XContentBuilder implements Closeable, Flushable {
 
     /**
      * Create a new {@link XContentBuilder} using the given {@link XContent} content.
@@ -91,7 +90,6 @@ public static XContentBuilder builder(XContent xContent, Set<String> includes, S
         writers.put(Boolean.class, (b, v) -> b.value((Boolean) v));
         writers.put(Byte.class, (b, v) -> b.value((Byte) v));
         writers.put(byte[].class, (b, v) -> b.value((byte[]) v));
-        writers.put(BytesRef.class, (b, v) -> b.binaryValue((BytesRef) v));
         writers.put(Date.class, (b, v) -> b.value((Date) v));
         writers.put(Double.class, (b, v) -> b.value((Double) v));
         writers.put(double[].class, (b, v) -> b.values((double[]) v));
@@ -105,12 +103,12 @@ public static XContentBuilder builder(XContent xContent, Set<String> includes, S
         writers.put(short[].class, (b, v) -> b.values((short[]) v));
         writers.put(String.class, (b, v) -> b.value((String) v));
         writers.put(String[].class, (b, v) -> b.values((String[]) v));
+        writers.put(Locale.class, (b, v) -> b.value(v.toString()));
+        writers.put(Class.class, (b, v) -> b.value(v.toString()));
+        writers.put(ZonedDateTime.class, (b, v) -> b.value(v.toString()));
 
 
         Map<Class<?>, HumanReadableTransformer> humanReadableTransformer = new HashMap<>();
-        // These will be moved to a different class at a later time to decouple them from XContentBuilder
-        humanReadableTransformer.put(TimeValue.class, v -> ((TimeValue) v).millis());
-        humanReadableTransformer.put(ByteSizeValue.class, v -> ((ByteSizeValue) v).getBytes());
 
         // Load pluggable extensions
         for (XContentBuilderExtension service : ServiceLoader.load(XContentBuilderExtension.class)) {
@@ -613,49 +611,25 @@ public XContentBuilder value(byte[] value, int offset, int length) throws IOExce
     }
 
     /**
-     * Writes the binary content of the given {@link BytesRef}.
-     *
-     * Use {@link org.elasticsearch.common.xcontent.XContentParser#binaryValue()} to read the value back
-     */
-    public XContentBuilder field(String name, BytesRef value) throws IOException {
-        return field(name).binaryValue(value);
-    }
-
-    /**
-     * Writes the binary content of the given {@link BytesRef} as UTF-8 bytes.
+     * Writes the binary content of the given byte array as UTF-8 bytes.
      *
      * Use {@link XContentParser#charBuffer()} to read the value back
      */
-    public XContentBuilder utf8Field(String name, BytesRef value) throws IOException {
-        return field(name).utf8Value(value);
-    }
-
-    /**
-     * Writes the binary content of the given {@link BytesRef}.
-     *
-     * Use {@link org.elasticsearch.common.xcontent.XContentParser#binaryValue()} to read the value back
-     */
-    public XContentBuilder binaryValue(BytesRef value) throws IOException {
-        if (value == null) {
-            return nullValue();
-        }
-        value(value.bytes, value.offset, value.length);
-        return this;
+    public XContentBuilder utf8Field(String name, byte[] bytes, int offset, int length) throws IOException {
+        return field(name).utf8Value(bytes, offset, length);
     }
 
     /**
-     * Writes the binary content of the given {@link BytesRef} as UTF-8 bytes.
+     * Writes the binary content of the given byte array as UTF-8 bytes.
      *
      * Use {@link XContentParser#charBuffer()} to read the value back
      */
-    public XContentBuilder utf8Value(BytesRef value) throws IOException {
-        if (value == null) {
-            return nullValue();
-        }
-        generator.writeUTF8String(value.bytes, value.offset, value.length);
+    public XContentBuilder utf8Value(byte[] bytes, int offset, int length) throws IOException {
+        generator.writeUTF8String(bytes, offset, length);
         return this;
     }
 
+
     ////////////////////////////////////////////////////////////////////////////
     // Date
     //////////////////////////////////
@@ -793,10 +767,11 @@ private void unknownValue(Object value, boolean ensureNoSelfReferences) throws I
             value((ReadableInstant) value);
         } else if (value instanceof ToXContent) {
             value((ToXContent) value);
-        } else {
-            // This is a "value" object (like enum, DistanceUnit, etc) just toString() it
-            // (yes, it can be misleading when toString a Java class, but really, jackson should be used in that case)
+        } else if (value instanceof Enum<?>) {
+            // Write out the Enum toString
             value(Objects.toString(value));
+        } else {
+            throw new IllegalArgumentException("cannot write xcontent for unknown value of type " + value.getClass());
         }
     }
 

server/src/main/java/org/elasticsearch/common/xcontent/XContentElasticsearchExtension.java

@@ -0,0 +1,78 @@
+/*
+ * Licensed to Elasticsearch under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch licenses this file to you under
+ * the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing,
+ * software distributed under the License is distributed on an
+ * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+ * KIND, either express or implied.  See the License for the
+ * specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.elasticsearch.common.xcontent;
+
+import org.apache.lucene.util.BytesRef;
+import org.elasticsearch.common.bytes.BytesReference;
+import org.elasticsearch.common.unit.ByteSizeValue;
+import org.elasticsearch.common.unit.TimeValue;
+import org.joda.time.DateTimeZone;
+import org.joda.time.tz.CachedDateTimeZone;
+import org.joda.time.tz.FixedDateTimeZone;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Objects;
+
+/**
+ * SPI extensions for Elasticsearch-specific classes (like the Lucene or Joda
+ * dependency classes) that need to be encoded by {@link XContentBuilder} in a
+ * specific way.
+ */
+public class XContentElasticsearchExtension implements XContentBuilderExtension {
+
+    @Override
+    public Map<Class<?>, XContentBuilder.Writer> getXContentWriters() {
+        Map<Class<?>, XContentBuilder.Writer> writers = new HashMap<>();
+
+        // Fully-qualified here to reduce ambiguity around our (ES') Version class
+        writers.put(org.apache.lucene.util.Version.class, (b, v) -> b.value(Objects.toString(v)));
+        writers.put(DateTimeZone.class, (b, v) -> b.value(Objects.toString(v)));
+        writers.put(CachedDateTimeZone.class, (b, v) -> b.value(Objects.toString(v)));
+        writers.put(FixedDateTimeZone.class, (b, v) -> b.value(Objects.toString(v)));
+
+        writers.put(BytesReference.class, (b, v) -> {
+            if (v == null) {
+                b.nullValue();
+            } else {
+                BytesRef bytes = ((BytesReference) v).toBytesRef();
+                b.value(bytes.bytes, bytes.offset, bytes.length);
+            }
+        });
+
+        writers.put(BytesRef.class, (b, v) -> {
+            if (v == null) {
+                b.nullValue();
+            } else {
+                BytesRef bytes = (BytesRef) v;
+                b.value(bytes.bytes, bytes.offset, bytes.length);
+            }
+        });
+        return writers;
+    }
+
+    @Override
+    public Map<Class<?>, XContentBuilder.HumanReadableTransformer> getXContentHumanReadableTransformers() {
+        Map<Class<?>, XContentBuilder.HumanReadableTransformer> transformers = new HashMap<>();
+        transformers.put(TimeValue.class, v -> ((TimeValue) v).millis());
+        transformers.put(ByteSizeValue.class, v -> ((ByteSizeValue) v).getBytes());
+        return transformers;
+    }
+}