Revert "Add XContentFieldFilter (#81970)" (#82897)

This reverts commit 4560a0c5cd97965f77dcda10d73739e1d25a928a. It
unexpectedly caused #82891.

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

@@ -1,76 +0,0 @@
-/*
- * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
- * or more contributor license agreements. Licensed under the Elastic License
- * 2.0 and the Server Side Public License, v 1; you may not use this file except
- * in compliance with, at your election, the Elastic License 2.0 or the Server
- * Side Public License, v 1.
- */
-
-package org.elasticsearch.common.xcontent;
-
-import org.elasticsearch.common.bytes.BytesReference;
-import org.elasticsearch.common.io.stream.BytesStreamOutput;
-import org.elasticsearch.common.util.CollectionUtils;
-import org.elasticsearch.common.xcontent.support.XContentMapValues;
-import org.elasticsearch.core.Nullable;
-import org.elasticsearch.core.Tuple;
-import org.elasticsearch.xcontent.XContentBuilder;
-import org.elasticsearch.xcontent.XContentFactory;
-import org.elasticsearch.xcontent.XContentParser;
-import org.elasticsearch.xcontent.XContentParserConfiguration;
-import org.elasticsearch.xcontent.XContentType;
-
-import java.io.IOException;
-import java.util.Arrays;
-import java.util.Map;
-import java.util.Set;
-import java.util.function.Function;
-
-/**
- * A filter that filter fields away from source
- */
-public interface XContentFieldFilter {
-    /**
-     * filter source in {@link BytesReference} format and in {@link XContentType} content type
-     * note that xContentType may be null in some case, we should guess xContentType from sourceBytes in such cases
-     */
-    BytesReference apply(BytesReference sourceBytes, @Nullable XContentType xContentType) throws IOException;
-
-    /**
-     * Construct {@link XContentFieldFilter} using given includes and excludes
-     *
-     * @param includes fields to keep, wildcard supported
-     * @param excludes fields to remove, wildcard supported
-     * @return filter using {@link XContentMapValues#filter(String[], String[])} if wildcard found in excludes
-     *         , otherwise return filter using {@link XContentParser}
-     */
-    static XContentFieldFilter newFieldFilter(String[] includes, String[] excludes) {
-        if ((CollectionUtils.isEmpty(excludes) == false) && Arrays.stream(excludes).filter(field -> field.contains("*")).count() > 0) {
-            return (originalSource, contentType) -> {
-                Function<Map<String, ?>, Map<String, Object>> mapFilter = XContentMapValues.filter(includes, excludes);
-                Tuple<XContentType, Map<String, Object>> mapTuple = XContentHelper.convertToMap(originalSource, true, contentType);
-                Map<String, Object> filteredSource = mapFilter.apply(mapTuple.v2());
-                BytesStreamOutput bStream = new BytesStreamOutput();
-                XContentType actualContentType = mapTuple.v1();
-                XContentBuilder builder = XContentFactory.contentBuilder(actualContentType, bStream).map(filteredSource);
-                builder.close();
-                return bStream.bytes();
-            };
-        } else {
-            final XContentParserConfiguration parserConfig = XContentParserConfiguration.EMPTY.withFiltering(
-                Set.of(includes),
-                Set.of(excludes)
-            );
-            return (originalSource, contentType) -> {
-                if (contentType == null) {
-                    contentType = XContentHelper.xContentTypeMayCompressed(originalSource);
-                }
-                BytesStreamOutput streamOutput = new BytesStreamOutput(Math.min(1024, originalSource.length()));
-                XContentBuilder builder = new XContentBuilder(contentType.xContent(), streamOutput);
-                XContentParser parser = contentType.xContent().createParser(parserConfig, originalSource.streamInput());
-                builder.copyCurrentStructure(parser);
-                return BytesReference.bytes(builder);
-            };
-        }
-    }
-}

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

@@ -522,32 +522,6 @@ public class XContentHelper {
         }
     }
 
-    /**
-     * Guesses the content type based on the provided bytes which may be compressed.
-     *
-     * @deprecated the content type should not be guessed except for few cases where we effectively don't know the content type.
-     * The REST layer should move to reading the Content-Type header instead. There are other places where auto-detection may be needed.
-     * This method is deprecated to prevent usages of it from spreading further without specific reasons.
-     */
-    @Deprecated
-    public static XContentType xContentTypeMayCompressed(BytesReference bytes) {
-        Compressor compressor = CompressorFactory.compressor(bytes);
-        if (compressor != null) {
-            try {
-                InputStream compressedStreamInput = compressor.threadLocalInputStream(bytes.streamInput());
-                if (compressedStreamInput.markSupported() == false) {
-                    compressedStreamInput = new BufferedInputStream(compressedStreamInput);
-                }
-                return XContentFactory.xContentType(compressedStreamInput);
-            } catch (IOException e) {
-                assert false : "Should not happen, we're just reading bytes from memory";
-                throw new UncheckedIOException(e);
-            }
-        } else {
-            return XContentHelper.xContentType(bytes);
-        }
-    }
-
     /**
      * Guesses the content type based on the provided bytes.
      *

server/src/main/java/org/elasticsearch/index/get/ShardGetService.java

@@ -16,8 +16,10 @@ import org.elasticsearch.common.lucene.uid.VersionsAndSeqNoResolver.DocIdAndVers
 import org.elasticsearch.common.metrics.CounterMetric;
 import org.elasticsearch.common.metrics.MeanMetric;
 import org.elasticsearch.common.util.set.Sets;
-import org.elasticsearch.common.xcontent.XContentFieldFilter;
+import org.elasticsearch.common.xcontent.XContentHelper;
+import org.elasticsearch.common.xcontent.support.XContentMapValues;
 import org.elasticsearch.core.Nullable;
+import org.elasticsearch.core.Tuple;
 import org.elasticsearch.index.IndexSettings;
 import org.elasticsearch.index.VersionType;
 import org.elasticsearch.index.engine.Engine;
@@ -31,6 +33,8 @@ import org.elasticsearch.index.mapper.SourceFieldMapper;
 import org.elasticsearch.index.shard.AbstractIndexShardComponent;
 import org.elasticsearch.index.shard.IndexShard;
 import org.elasticsearch.search.fetch.subphase.FetchSourceContext;
+import org.elasticsearch.xcontent.XContentFactory;
+import org.elasticsearch.xcontent.XContentType;
 
 import java.io.IOException;
 import java.util.HashMap;
@@ -249,11 +253,15 @@ public final class ShardGetService extends AbstractIndexShardComponent {
             if (fetchSourceContext.fetchSource() == false) {
                 source = null;
             } else if (fetchSourceContext.includes().length > 0 || fetchSourceContext.excludes().length > 0) {
+                Map<String, Object> sourceAsMap;
                 // TODO: The source might be parsed and available in the sourceLookup but that one uses unordered maps so different.
                 // Do we care?
+                Tuple<XContentType, Map<String, Object>> typeMapTuple = XContentHelper.convertToMap(source, true);
+                XContentType sourceContentType = typeMapTuple.v1();
+                sourceAsMap = typeMapTuple.v2();
+                sourceAsMap = XContentMapValues.filter(sourceAsMap, fetchSourceContext.includes(), fetchSourceContext.excludes());
                 try {
-                    source = XContentFieldFilter.newFieldFilter(fetchSourceContext.includes(), fetchSourceContext.excludes())
-                        .apply(source, null);
+                    source = BytesReference.bytes(XContentFactory.contentBuilder(sourceContentType).map(sourceAsMap));
                 } catch (IOException e) {
                     throw new ElasticsearchException("Failed to get id [" + id + "] with includes/excludes set", e);
                 }

server/src/main/java/org/elasticsearch/index/mapper/SourceFieldMapper.java

@@ -16,24 +16,32 @@ import org.apache.lucene.search.Query;
 import org.apache.lucene.util.BytesRef;
 import org.elasticsearch.common.Strings;
 import org.elasticsearch.common.bytes.BytesReference;
+import org.elasticsearch.common.io.stream.BytesStreamOutput;
 import org.elasticsearch.common.util.CollectionUtils;
-import org.elasticsearch.common.xcontent.XContentFieldFilter;
+import org.elasticsearch.common.xcontent.XContentHelper;
+import org.elasticsearch.common.xcontent.support.XContentMapValues;
 import org.elasticsearch.core.Nullable;
+import org.elasticsearch.core.Tuple;
 import org.elasticsearch.index.query.QueryShardException;
 import org.elasticsearch.index.query.SearchExecutionContext;
+import org.elasticsearch.xcontent.XContentBuilder;
+import org.elasticsearch.xcontent.XContentFactory;
 import org.elasticsearch.xcontent.XContentType;
 
 import java.io.IOException;
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.List;
+import java.util.Map;
+import java.util.function.Function;
 
 public class SourceFieldMapper extends MetadataFieldMapper {
+
     public static final String NAME = "_source";
     public static final String RECOVERY_SOURCE_NAME = "_recovery_source";
 
     public static final String CONTENT_TYPE = "_source";
-    private final XContentFieldFilter filter;
+    private final Function<Map<String, ?>, Map<String, Object>> filter;
 
     private static final SourceFieldMapper DEFAULT = new SourceFieldMapper(Defaults.ENABLED, Strings.EMPTY_ARRAY, Strings.EMPTY_ARRAY);
 
@@ -137,9 +145,7 @@ public class SourceFieldMapper extends MetadataFieldMapper {
         this.includes = includes;
         this.excludes = excludes;
         final boolean filtered = CollectionUtils.isEmpty(includes) == false || CollectionUtils.isEmpty(excludes) == false;
-        this.filter = enabled && filtered
-            ? XContentFieldFilter.newFieldFilter(includes, excludes)
-            : (sourceBytes, contentType) -> sourceBytes;
+        this.filter = enabled && filtered ? XContentMapValues.filter(includes, excludes) : null;
         this.complete = enabled && CollectionUtils.isEmpty(includes) && CollectionUtils.isEmpty(excludes);
     }
 
@@ -174,7 +180,18 @@ public class SourceFieldMapper extends MetadataFieldMapper {
     public BytesReference applyFilters(@Nullable BytesReference originalSource, @Nullable XContentType contentType) throws IOException {
         if (enabled && originalSource != null) {
             // Percolate and tv APIs may not set the source and that is ok, because these APIs will not index any data
-            return filter.apply(originalSource, contentType);
+            if (filter != null) {
+                // we don't update the context source if we filter, we want to keep it as is...
+                Tuple<XContentType, Map<String, Object>> mapTuple = XContentHelper.convertToMap(originalSource, true, contentType);
+                Map<String, Object> filteredSource = filter.apply(mapTuple.v2());
+                BytesStreamOutput bStream = new BytesStreamOutput();
+                XContentType actualContentType = mapTuple.v1();
+                XContentBuilder builder = XContentFactory.contentBuilder(actualContentType, bStream).map(filteredSource);
+                builder.close();
+                return bStream.bytes();
+            } else {
+                return originalSource;
+            }
         } else {
             return null;
         }