Decouple XContentGenerator and JsonXContentGenerator from BytesReference (#28772)

This removes the link these two classes have with BytesReference, in favor of an
`InputStream` approach.

Relates to #28504

server/src/main/java/org/elasticsearch/action/admin/indices/mapping/put/PutMappingRequest.java

@@ -323,7 +323,7 @@ public class PutMappingRequest extends AcknowledgedRequest<PutMappingRequest> im
     @Override
     public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
         if (source != null) {
-            builder.rawValue(new BytesArray(source), XContentType.JSON);
+            builder.rawValue(new BytesArray(source).streamInput(), XContentType.JSON);
         } else {
             builder.startObject().endObject();
         }

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

@@ -987,7 +987,7 @@ public final class XContentBuilder implements Releasable, Flushable {
      */
     @Deprecated
     public XContentBuilder rawField(String name, BytesReference value) throws IOException {
-        generator.writeRawField(name, value);
+        generator.writeRawField(name, value.streamInput());
         return this;
     }
 
@@ -995,25 +995,15 @@ public final class XContentBuilder implements Releasable, Flushable {
      * Writes a raw field with the given bytes as the value
      */
     public XContentBuilder rawField(String name, BytesReference value, XContentType contentType) throws IOException {
-        generator.writeRawField(name, value, contentType);
+        generator.writeRawField(name, value.streamInput(), contentType);
         return this;
     }
 
     /**
-     * Writes a value with the source coming directly from the bytes
+     * Writes a value with the source coming directly from the bytes in the stream
-     * @deprecated use {@link #rawValue(BytesReference, XContentType)} to avoid content type auto-detection
      */
-    @Deprecated
+    public XContentBuilder rawValue(InputStream stream, XContentType contentType) throws IOException {
-    public XContentBuilder rawValue(BytesReference value) throws IOException {
+        generator.writeRawValue(stream, contentType);
-        generator.writeRawValue(value);
-        return this;
-    }
-
-    /**
-     * Writes a value with the source coming directly from the bytes
-     */
-    public XContentBuilder rawValue(BytesReference value, XContentType contentType) throws IOException {
-        generator.writeRawValue(value, contentType);
         return this;
     }
 

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

@@ -19,8 +19,6 @@
 
 package org.elasticsearch.common.xcontent;
 
-import org.elasticsearch.common.bytes.BytesReference;
-
 import java.io.Closeable;
 import java.io.Flushable;
 import java.io.IOException;
@@ -99,28 +97,9 @@ public interface XContentGenerator extends Closeable, Flushable {
     void writeRawField(String name, InputStream value, XContentType xContentType) throws IOException;
 
     /**
-     * Writes a raw field with the given bytes as the value
+     * Writes a raw value taken from the bytes in the stream
-     * @deprecated use {@link #writeRawField(String, BytesReference, XContentType)} to avoid content type auto-detection
      */
-    @Deprecated
+    void writeRawValue(InputStream value, XContentType xContentType) throws IOException;
-    void writeRawField(String name, BytesReference value) throws IOException;
-
-    /**
-     * Writes a raw field with the given bytes as the value
-     */
-    void writeRawField(String name, BytesReference value, XContentType xContentType) throws IOException;
-
-    /**
-     * Writes a value with the source coming directly from the bytes
-     * @deprecated use {@link #writeRawValue(BytesReference, XContentType)} to avoid content type auto-detection
-     */
-    @Deprecated
-    void writeRawValue(BytesReference value) throws IOException;
-
-    /**
-     * Writes a value with the source coming directly from the bytes
-     */
-    void writeRawValue(BytesReference value, XContentType xContentType) throws IOException;
 
     void copyCurrentStructure(XContentParser parser) throws IOException;
 

server/src/main/java/org/elasticsearch/common/xcontent/json/JsonXContentGenerator.java

@@ -28,9 +28,7 @@ import com.fasterxml.jackson.core.json.JsonWriteContext;
 import com.fasterxml.jackson.core.util.DefaultIndenter;
 import com.fasterxml.jackson.core.util.DefaultPrettyPrinter;
 import com.fasterxml.jackson.core.util.JsonGeneratorDelegate;
-import org.elasticsearch.common.bytes.BytesReference;
 import org.elasticsearch.common.io.Streams;
-import org.elasticsearch.common.io.stream.StreamInput;
 import org.elasticsearch.common.xcontent.DeprecationHandler;
 import org.elasticsearch.common.xcontent.NamedXContentRegistry;
 import org.elasticsearch.common.xcontent.XContent;
@@ -333,51 +331,33 @@ public class JsonXContentGenerator implements XContentGenerator {
     }
 
     @Override
-    public final void writeRawField(String name, BytesReference content) throws IOException {
+    public void writeRawValue(InputStream stream, XContentType xContentType) throws IOException {
-        XContentType contentType = XContentFactory.xContentType(content);
+        if (mayWriteRawData(xContentType) == false) {
-        if (contentType == null) {
+            copyRawValue(stream, xContentType.xContent());
-            throw new IllegalArgumentException("Can't write raw bytes whose xcontent-type can't be guessed");
-        }
-        writeRawField(name, content, contentType);
-    }
-
-    @Override
-    public final void writeRawField(String name, BytesReference content, XContentType contentType) throws IOException {
-        if (mayWriteRawData(contentType) == false) {
-            writeFieldName(name);
-            copyRawValue(content, contentType.xContent());
-        } else {
-            writeStartRaw(name);
-            flush();
-            content.writeTo(os);
-            writeEndRaw();
-        }
-    }
-
-    @Override
-    public final void writeRawValue(BytesReference content) throws IOException {
-        XContentType contentType = XContentFactory.xContentType(content);
-        if (contentType == null) {
-            throw new IllegalArgumentException("Can't write raw bytes whose xcontent-type can't be guessed");
-        }
-        writeRawValue(content, contentType);
-    }
-
-    @Override
-    public final void writeRawValue(BytesReference content, XContentType contentType) throws IOException {
-        if (mayWriteRawData(contentType) == false) {
-            copyRawValue(content, contentType.xContent());
         } else {
             if (generator.getOutputContext().getCurrentName() != null) {
                 // If we've just started a field we'll need to add the separator
                 generator.writeRaw(':');
             }
             flush();
-            content.writeTo(os);
+            transfer(stream, os);
             writeEndRaw();
         }
     }
 
+    // A basic copy of Java 9's InputStream#transferTo
+    private static long transfer(InputStream in, OutputStream out) throws IOException {
+        Objects.requireNonNull(out, "out");
+        long transferred = 0;
+        byte[] buffer = new byte[8192];
+        int read;
+        while ((read = in.read(buffer, 0, 8192)) >= 0) {
+            out.write(buffer, 0, read);
+            transferred += read;
+        }
+        return transferred;
+    }
+
     private boolean mayWriteRawData(XContentType contentType) {
         // When the current generator is filtered (ie filter != null)
         // or the content is in a different format than the current generator,
@@ -394,13 +374,12 @@ public class JsonXContentGenerator implements XContentGenerator {
         return true;
     }
 
-    protected void copyRawValue(BytesReference content, XContent xContent) throws IOException {
+    protected void copyRawValue(InputStream stream, XContent xContent) throws IOException {
         // EMPTY is safe here because we never call namedObject
-        try (StreamInput input = content.streamInput();
+        try (XContentParser parser = xContent
-             XContentParser parser = xContent
                  // It's okay to pass the throwing deprecation handler because we
                  // should not be writing raw fields when generating JSON
-                 .createParser(NamedXContentRegistry.EMPTY, DeprecationHandler.THROW_UNSUPPORTED_OPERATION, input)) {
+                 .createParser(NamedXContentRegistry.EMPTY, DeprecationHandler.THROW_UNSUPPORTED_OPERATION, stream)) {
             copyCurrentStructure(parser);
         }
     }

server/src/main/java/org/elasticsearch/rest/action/document/RestGetSourceAction.java

@@ -23,8 +23,10 @@ import org.elasticsearch.action.ActionRequestValidationException;
 import org.elasticsearch.action.get.GetRequest;
 import org.elasticsearch.action.get.GetResponse;
 import org.elasticsearch.client.node.NodeClient;
+import org.elasticsearch.common.bytes.BytesReference;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.xcontent.XContentBuilder;
+import org.elasticsearch.common.xcontent.XContentFactory;
 import org.elasticsearch.rest.BaseRestHandler;
 import org.elasticsearch.rest.BytesRestResponse;
 import org.elasticsearch.rest.RestController;
@@ -81,7 +83,8 @@ public class RestGetSourceAction extends BaseRestHandler {
                         if (response.isSourceEmpty()) {
                             return new BytesRestResponse(NOT_FOUND, builder);
                         } else {
-                            builder.rawValue(response.getSourceInternal());
+                            final BytesReference source = response.getSourceInternal();
+                            builder.rawValue(source.streamInput(), XContentFactory.xContentType(source));
                             return new BytesRestResponse(OK, builder);
                         }
                     }

server/src/main/java/org/elasticsearch/tasks/RawTaskStatus.java

@@ -24,6 +24,7 @@ import org.elasticsearch.common.bytes.BytesReference;
 import org.elasticsearch.common.io.stream.StreamInput;
 import org.elasticsearch.common.io.stream.StreamOutput;
 import org.elasticsearch.common.xcontent.XContentBuilder;
+import org.elasticsearch.common.xcontent.XContentFactory;
 
 import java.io.IOException;
 import java.util.Map;
@@ -57,7 +58,7 @@ public class RawTaskStatus implements Task.Status {
 
     @Override
     public XContentBuilder toXContent(XContentBuilder builder, Params params) throws IOException {
-        return builder.rawValue(status);
+        return builder.rawValue(status.streamInput(), XContentFactory.xContentType(status));
     }
 
     @Override

server/src/test/java/org/elasticsearch/common/xcontent/BaseXContentTestCase.java

@@ -748,7 +748,7 @@ public abstract class BaseXContentTestCase extends ESTestCase {
             if (useStream) {
                 generator.writeRawField("bar", new ByteArrayInputStream(rawData));
             } else {
-                generator.writeRawField("bar", new BytesArray(rawData));
+                generator.writeRawField("bar", new BytesArray(rawData).streamInput());
             }
             generator.writeEndObject();
         }
@@ -785,7 +785,7 @@ public abstract class BaseXContentTestCase extends ESTestCase {
 
         os = new ByteArrayOutputStream();
         try (XContentGenerator generator = xcontentType().xContent().createGenerator(os)) {
-            generator.writeRawValue(new BytesArray(rawData));
+            generator.writeRawValue(new BytesArray(rawData).streamInput(), source.type());
         }
 
         XContentParser parser = xcontentType().xContent()
@@ -801,7 +801,7 @@ public abstract class BaseXContentTestCase extends ESTestCase {
         try (XContentGenerator generator = xcontentType().xContent().createGenerator(os)) {
             generator.writeStartObject();
             generator.writeFieldName("test");
-            generator.writeRawValue(new BytesArray(rawData));
+            generator.writeRawValue(new BytesArray(rawData).streamInput(), source.type());
             generator.writeEndObject();
         }