Remove FastStringReader in favor of vanilla StringReader (#28944)

This allows us to remove another dependency in the decoupling of the XContent
code. Rather than move this class over or decouple it, it can simply be removed.

Relates tangentially to #28504

Author: dakrone

buildSrc/src/main/resources/forbidden/es-server-signatures.txt

@@ -29,8 +29,6 @@ java.util.concurrent.Executors#privilegedThreadFactory()
 java.lang.Character#codePointBefore(char[],int) @ Implicit start offset is error-prone when the char[] is a buffer and the first chars are random chars
 java.lang.Character#codePointAt(char[],int) @ Implicit end offset is error-prone when the char[] is a buffer and the last chars are random chars
 
-java.io.StringReader#<init>(java.lang.String) @ Use FastStringReader instead
-
 @defaultMessage Reference management is tricky, leave it to SearcherManager
 org.apache.lucene.index.IndexReader#decRef()
 org.apache.lucene.index.IndexReader#incRef()

modules/lang-mustache/src/main/java/org/elasticsearch/script/mustache/MustacheScriptEngine.java

@@ -21,11 +21,11 @@
 import com.github.mustachejava.Mustache;
 import com.github.mustachejava.MustacheFactory;
 
+import java.io.StringReader;
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
 import org.apache.logging.log4j.util.Supplier;
 import org.elasticsearch.SpecialPermission;
-import org.elasticsearch.common.io.FastStringReader;
 import org.elasticsearch.common.logging.ESLoggerFactory;
 import org.elasticsearch.script.GeneralScriptException;
 import org.elasticsearch.script.Script;
@@ -65,7 +65,7 @@ public <T> T compile(String templateName, String templateSource, ScriptContext<T
             throw new IllegalArgumentException("mustache engine does not know how to handle context [" + context.name + "]");
         }
         final MustacheFactory factory = createMustacheFactory(options);
-        Reader reader = new FastStringReader(templateSource);
+        Reader reader = new StringReader(templateSource);
         Mustache template = factory.compile(reader, "query-template");
         TemplateScript.Factory compiled = params -> new MustacheExecutableScript(template, params);
         return context.factoryClazz.cast(compiled);

server/src/main/java/org/elasticsearch/action/admin/indices/analyze/TransportAnalyzeAction.java

@@ -41,7 +41,6 @@
 import org.elasticsearch.common.UUIDs;
 import org.elasticsearch.common.collect.Tuple;
 import org.elasticsearch.common.inject.Inject;
-import org.elasticsearch.common.io.FastStringReader;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.env.Environment;
 import org.elasticsearch.index.IndexService;
@@ -66,6 +65,7 @@
 
 import java.io.IOException;
 import java.io.Reader;
+import java.io.StringReader;
 import java.util.ArrayList;
 import java.util.HashSet;
 import java.util.List;
@@ -315,12 +315,12 @@ private static DetailAnalyzeResponse detailAnalyze(AnalyzeRequest request, Analy
             for (int textIndex = 0; textIndex < request.text().length; textIndex++) {
                 String charFilteredSource = request.text()[textIndex];
 
-                Reader reader = new FastStringReader(charFilteredSource);
+                Reader reader = new StringReader(charFilteredSource);
                 if (charFilterFactories != null) {
 
                     for (int charFilterIndex = 0; charFilterIndex < charFilterFactories.length; charFilterIndex++) {
                         reader = charFilterFactories[charFilterIndex].create(reader);
-                        Reader readerForWriteOut = new FastStringReader(charFilteredSource);
+                        Reader readerForWriteOut = new StringReader(charFilteredSource);
                         readerForWriteOut = charFilterFactories[charFilterIndex].create(readerForWriteOut);
                         charFilteredSource = writeCharStream(readerForWriteOut);
                         charFiltersTexts[charFilterIndex][textIndex] = charFilteredSource;
@@ -380,7 +380,7 @@ private static DetailAnalyzeResponse detailAnalyze(AnalyzeRequest request, Analy
     }
 
     private static TokenStream createStackedTokenStream(String source, CharFilterFactory[] charFilterFactories, TokenizerFactory tokenizerFactory, TokenFilterFactory[] tokenFilterFactories, int current) {
-        Reader reader = new FastStringReader(source);
+        Reader reader = new StringReader(source);
         for (CharFilterFactory charFilterFactory : charFilterFactories) {
             reader = charFilterFactory.create(reader);
         }

server/src/main/java/org/elasticsearch/common/Strings.java

@@ -23,14 +23,14 @@
 import org.elasticsearch.ElasticsearchException;
 import org.elasticsearch.ExceptionsHelper;
 import org.elasticsearch.common.bytes.BytesReference;
-import org.elasticsearch.common.io.FastStringReader;
 import org.elasticsearch.common.util.CollectionUtils;
 import org.elasticsearch.common.xcontent.ToXContent;
 import org.elasticsearch.common.xcontent.XContentBuilder;
 import org.elasticsearch.common.xcontent.json.JsonXContent;
 
 import java.io.BufferedReader;
 import java.io.IOException;
+import java.io.StringReader;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
@@ -51,7 +51,7 @@ public class Strings {
     public static final String[] EMPTY_ARRAY = new String[0];
 
     public static void spaceify(int spaces, String from, StringBuilder to) throws Exception {
-        try (BufferedReader reader = new BufferedReader(new FastStringReader(from))) {
+        try (BufferedReader reader = new BufferedReader(new StringReader(from))) {
             String line;
             while ((line = reader.readLine()) != null) {
                 for (int i = 0; i < spaces; i++) {

server/src/main/java/org/elasticsearch/common/geo/parsers/GeoWKTParser.java

@@ -22,6 +22,7 @@
 import org.elasticsearch.ElasticsearchParseException;
 import org.elasticsearch.common.geo.GeoShapeType;
 
+import java.io.StringReader;
 import org.elasticsearch.common.geo.builders.CoordinatesBuilder;
 import org.elasticsearch.common.geo.builders.EnvelopeBuilder;
 import org.elasticsearch.common.geo.builders.GeometryCollectionBuilder;
@@ -32,7 +33,6 @@
 import org.elasticsearch.common.geo.builders.PointBuilder;
 import org.elasticsearch.common.geo.builders.PolygonBuilder;
 import org.elasticsearch.common.geo.builders.ShapeBuilder;
-import org.elasticsearch.common.io.FastStringReader;
 import org.elasticsearch.common.logging.Loggers;
 import org.elasticsearch.common.xcontent.XContentParser;
 
@@ -69,7 +69,7 @@ public static ShapeBuilder parse(XContentParser parser)
     /** throws an exception if the parsed geometry type does not match the expected shape type */
     public static ShapeBuilder parseExpectedType(XContentParser parser, final GeoShapeType shapeType)
             throws IOException, ElasticsearchParseException {
-        FastStringReader reader = new FastStringReader(parser.text());
+        StringReader reader = new StringReader(parser.text());
         try {
             // setup the tokenizer; configured to read words w/o numbers
             StreamTokenizer tokenizer = new StreamTokenizer(reader);

server/src/main/java/org/elasticsearch/common/io/FastStringReader.java

@@ -35,10 +35,10 @@
 import org.apache.lucene.search.similarities.TFIDFSimilarity;
 import org.apache.lucene.util.BytesRef;
 import org.elasticsearch.common.Strings;
-import org.elasticsearch.common.io.FastStringReader;
 
 import java.io.IOException;
 import java.io.Reader;
+import java.io.StringReader;
 import java.util.Arrays;
 import java.util.HashSet;
 import java.util.List;
@@ -166,7 +166,7 @@ private Query createQuery(XMoreLikeThis mlt) throws IOException {
         if (this.likeText != null) {
             Reader[] readers = new Reader[likeText.length];
             for (int i = 0; i < readers.length; i++) {
-                readers[i] = new FastStringReader(likeText[i]);
+                readers[i] = new StringReader(likeText[i]);
             }
             //LUCENE 4 UPGRADE this mapps the 3.6 behavior (only use the first field)
             Query mltQuery = mlt.like(moreLikeFields[0], readers);

server/src/main/java/org/elasticsearch/common/lucene/search/MoreLikeThisQuery.java

@@ -58,10 +58,10 @@
 import org.apache.lucene.util.CharsRefBuilder;
 import org.apache.lucene.util.PriorityQueue;
 import org.elasticsearch.common.Nullable;
-import org.elasticsearch.common.io.FastStringReader;
 
 import java.io.IOException;
 import java.io.Reader;
+import java.io.StringReader;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.HashMap;
@@ -815,7 +815,7 @@ private PriorityQueue<ScoreTerm> retrieveTerms(int docNum) throws IOException {
                 for (IndexableField field : fields) {
                     final String stringValue = field.stringValue();
                     if (stringValue != null) {
-                        addTermFrequencies(new FastStringReader(stringValue), termFreqMap, fieldName);
+                        addTermFrequencies(new StringReader(stringValue), termFreqMap, fieldName);
                     }
                 }
             } else {

server/src/main/java/org/elasticsearch/common/lucene/search/XMoreLikeThis.java

@@ -24,7 +24,6 @@
 import com.fasterxml.jackson.core.JsonParser;
 import com.fasterxml.jackson.dataformat.cbor.CBORFactory;
 import org.elasticsearch.ElasticsearchParseException;
-import org.elasticsearch.common.io.FastStringReader;
 import org.elasticsearch.common.xcontent.DeprecationHandler;
 import org.elasticsearch.common.xcontent.NamedXContentRegistry;
 import org.elasticsearch.common.xcontent.XContent;
@@ -37,6 +36,7 @@
 import java.io.InputStream;
 import java.io.OutputStream;
 import java.io.Reader;
+import java.io.StringReader;
 import java.util.Set;
 
 /**
@@ -81,7 +81,7 @@ public XContentGenerator createGenerator(OutputStream os, Set<String> includes,
     @Override
     public XContentParser createParser(NamedXContentRegistry xContentRegistry,
             DeprecationHandler deprecationHandler, String content) throws IOException {
-        return new CborXContentParser(xContentRegistry, deprecationHandler, cborFactory.createParser(new FastStringReader(content)));
+        return new CborXContentParser(xContentRegistry, deprecationHandler, cborFactory.createParser(new StringReader(content)));
     }
 
     @Override