Refactor media types parsing improvements

Issue: SPR-17459

spring-core/src/main/java/org/springframework/util/MimeTypeUtils.java

@@ -28,6 +28,7 @@ import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.Random;
+import java.util.stream.Collectors;
 
 import org.springframework.lang.Nullable;
 import org.springframework.util.MimeType.SpecificityComparator;
@@ -249,32 +250,53 @@ public abstract class MimeTypeUtils {
 	}
 
 	/**
-	 * Parse the given, comma-separated string into a list of {@code MimeType} objects.
+	 * Parse the comma-separated string into a list of {@code MimeType} objects.
 	 * @param mimeTypes the string to parse
 	 * @return the list of mime types
-	 * @throws IllegalArgumentException if the string cannot be parsed
+	 * @throws InvalidMimeTypeException if the string cannot be parsed
 	 */
 	public static List<MimeType> parseMimeTypes(String mimeTypes) {
 		if (!StringUtils.hasLength(mimeTypes)) {
 			return Collections.emptyList();
 		}
-		boolean isQuoted = false;
-		int nextBeginIndex = 0;
-		List<MimeType> tokens = new ArrayList<>();
-		for(int i = 0; i < mimeTypes.length() - 1; i++) {
-			//tokenizing on commas that are not within double quotes
-			if(mimeTypes.charAt(i) == ',' && !isQuoted) {
-				tokens.add(parseMimeType(mimeTypes.substring(nextBeginIndex,i)));
-				nextBeginIndex = i + 1;
-			//ignoring escaped double quote within double quotes
-			} else if(isQuoted && mimeTypes.charAt(i) == '"' && mimeTypes.charAt(i-1) == '\\') {
-				continue;
-			} else if(mimeTypes.charAt(i) == '"') {
-				isQuoted = !isQuoted;
+		return tokenize(mimeTypes).stream()
+				.map(MimeTypeUtils::parseMimeType).collect(Collectors.toList());
+	}
+
+	/**
+	 * Tokenize the given comma-separated string of {@code MimeType} objects
+	 * into a {@code List<String>}. Unlike simple tokenization by ",", this
+	 * method takes into account quoted parameters.
+	 * @param mimeTypes the string to tokenize
+	 * @return the list of tokens
+	 * @since 5.1.3
+	 */
+	public static List<String> tokenize(String mimeTypes) {
+		if (!StringUtils.hasLength(mimeTypes)) {
+			return Collections.emptyList();
+		}
+		List<String> tokens = new ArrayList<>();
+		boolean inQuotes = false;
+		int startIndex = 0;
+		int i = 0;
+		while (i < mimeTypes.length()) {
+			switch (mimeTypes.charAt(i)) {
+				case '"':
+					inQuotes = !inQuotes;
+					break;
+				case ',':
+					if (!inQuotes) {
+						tokens.add(mimeTypes.substring(startIndex, i));
+						startIndex = i + 1;
+					}
+					break;
+				case '\\':
+					i++;
+					break;
 			}
+			i++;
 		}
-		//either the last part of the tokenization or the original string
-		tokens.add(parseMimeType(mimeTypes.substring(nextBeginIndex)));
+		tokens.add(mimeTypes.substring(startIndex));
 		return tokens;
 	}
 

spring-core/src/test/java/org/springframework/util/MimeTypeTests.java

@@ -277,54 +277,23 @@ public class MimeTypeTests {
 		assertEquals("Invalid amount of mime types", 0, mimeTypes.size());
 	}
 
-	// SPR-17459
-	@Test
-	public void parseMimeTypesWithOddNumberOfDoubleQuotedCommas() {
-		String s = "foo/bar;param=\",\"";
-		List<MimeType> mimeTypes = MimeTypeUtils.parseMimeTypes(s);
-		assertEquals("Invalid amount of mime types", 1, mimeTypes.size());
-		assertEquals("Comma should be part of the mime type", s, mimeTypes.get(0).toString());
-	}
-
-	// SPR-17459
-	@Test
-	public void parseMimeTypesWithEvenNumberOfDoubleQuotedCommas() {
-		String s = "foo/bar;param=\"s,a,\"";
-		List<MimeType> mimeTypes = MimeTypeUtils.parseMimeTypes(s);
-		assertEquals("Invalid amount of mime types", 1, mimeTypes.size());
-		assertEquals("Comma should be part of the mime type", s, mimeTypes.get(0).toString());
-	}
-
-	// SPR-17459
-	@Test
-	public void parseMimeTypesWithAndWithoutDoubleQuotedCommas() {
-		String s = "foo/bar;param=\"s,\", text/x-c";
-		List<MimeType> mimeTypes = MimeTypeUtils.parseMimeTypes(s);
-		assertEquals("Invalid amount of mime types", 2, mimeTypes.size());
-		assertEquals("Comma should be part of the mime type", "foo/bar;param=\"s,\"", mimeTypes.get(0).toString());
-	}
-
-	// SPR-17459
-	@Test
-	public void parseMimeTypesIgnoreEscapedDoubleQuoteWithinDoubleQuotes() {
-		String s = "foo/bar;param=\"a\\\"b,c\"";
-		List<MimeType> mimeTypes = MimeTypeUtils.parseMimeTypes(s);
-		assertEquals("Invalid amount of mime types", 1, mimeTypes.size());
-		assertEquals("Escaped quote within quotes should be ignored when considering comma tokenization", s, mimeTypes.get(0).toString());
-	}
-
-	// SPR-17459
-	@Test
-	public void parseMimeTypesIgnoreEscapedBackslash() {
-		String s = "foo/bar;param=\"\\\\\"";
-		List<MimeType> mimeTypes = MimeTypeUtils.parseMimeTypes(s);
-		assertEquals("Invalid amount of mime types", 1, mimeTypes.size());
-		assertEquals("Escaped backslash should be ignored when considering comma tokenization", s, mimeTypes.get(0).toString());
-
-		s = "foo/bar;param=\"\\,\\\"";
-		mimeTypes = MimeTypeUtils.parseMimeTypes(s);
-		assertEquals("Invalid amount of mime types", 1, mimeTypes.size());
-		assertEquals("Escaped backslash should be ignored when considering comma tokenization", s, mimeTypes.get(0).toString());
+	@Test // SPR-17459
+	public void parseMimeTypesWithQuotedParameters() {
+		testWithQuotedParameters("foo/bar;param=\",\"");
+		testWithQuotedParameters("foo/bar;param=\"s,a,\"");
+		testWithQuotedParameters("foo/bar;param=\"s,\"", "text/x-c");
+		testWithQuotedParameters("foo/bar;param=\"a\\\"b,c\"");
+		testWithQuotedParameters("foo/bar;param=\"\\\\\"");
+		testWithQuotedParameters("foo/bar;param=\"\\,\\\"");
+	}
+
+	private void testWithQuotedParameters(String... mimeTypes) {
+		String s = String.join(",", mimeTypes);
+		List<MimeType> actual = MimeTypeUtils.parseMimeTypes(s);
+		assertEquals(mimeTypes.length, actual.size());
+		for (int i=0; i < mimeTypes.length; i++) {
+			assertEquals(mimeTypes[i], actual.get(i).toString());
+		}
 	}
 
 	@Test

spring-web/src/main/java/org/springframework/http/MediaType.java

@@ -44,7 +44,6 @@ import org.springframework.util.StringUtils;
  * @author Rossen Stoyanchev
  * @author Sebastien Deleuze
  * @author Kazuki Shimizu
- * @author Dimitrios Liapis
  * @since 3.0
  * @see <a href="http://tools.ietf.org/html/rfc7231#section-3.1.1.1">
  *     HTTP 1.1: Semantics and Content, section 3.1.1.1</a>
@@ -543,7 +542,7 @@ public class MediaType extends MimeType implements Serializable {
 	}
 
 	/**
-	 * Parse the given comma-separated string into a list of {@code MediaType} objects.
+	 * Parse the comma-separated string into a list of {@code MediaType} objects.
 	 * <p>This method can be used to parse an Accept or Content-Type header.
 	 * @param mediaTypes the string to parse
 	 * @return the list of media types
@@ -553,24 +552,8 @@ public class MediaType extends MimeType implements Serializable {
 		if (!StringUtils.hasLength(mediaTypes)) {
 			return Collections.emptyList();
 		}
-		boolean isQuoted = false;
-		int nextBeginIndex = 0;
-		List<MediaType> tokens = new ArrayList<>();
-		for(int i = 0; i < mediaTypes.length() - 1; i++) {
-			//tokenizing on commas that are not within double quotes
-			if(mediaTypes.charAt(i) == ',' && !isQuoted) {
-				tokens.add(parseMediaType(mediaTypes.substring(nextBeginIndex, i)));
-				nextBeginIndex = i + 1;
-			//ignoring escaped double quote within double quotes
-			} else if(isQuoted && mediaTypes.charAt(i) == '"' && mediaTypes.charAt(i-1) == '\\') {
-				continue;
-			} else if(mediaTypes.charAt(i) == '"') {
-				isQuoted = !isQuoted;
-			}
-		}
-		//either the last part of the tokenization or the original string
-		tokens.add(parseMediaType(mediaTypes.substring(nextBeginIndex)));
-		return tokens;
+		return MimeTypeUtils.tokenize(mediaTypes).stream()
+				.map(MediaType::parseMediaType).collect(Collectors.toList());
 	}
 
 	/**

spring-web/src/test/java/org/springframework/http/MediaTypeTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2018 the original author or authors.
+ * Copyright 2002-2016 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -32,7 +32,6 @@ import static org.junit.Assert.*;
 /**
  * @author Arjen Poutsma
  * @author Juergen Hoeller
- * @author Dimitrios Liapis
  */
 public class MediaTypeTests {
 
@@ -144,56 +143,6 @@ public class MediaTypeTests {
 		assertEquals("Invalid amount of media types", 0, mediaTypes.size());
 	}
 
-	// SPR-17459
-	@Test
-	public void parseMediaTypesWithOddNumberOfDoubleQuotedCommas() {
-		String s = "foo/bar;param=\",\"";
-		List<MediaType> mediaTypes = MediaType.parseMediaTypes(s);
-		assertEquals("Invalid amount of media types", 1, mediaTypes.size());
-		assertEquals("Comma should be part of the media type", s, mediaTypes.get(0).toString());
-	}
-
-	// SPR-17459
-	@Test
-	public void parseMediaTypesWithEvenNumberOfDoubleQuotedCommas() {
-		String s = "foo/bar;param=\"s,a,\"";
-		List<MediaType> mediaTypes = MediaType.parseMediaTypes(s);
-		assertEquals("Invalid amount of media types", 1, mediaTypes.size());
-		assertEquals("Comma should be part of the media type", s, mediaTypes.get(0).toString());
-	}
-
-	// SPR-17459
-	@Test
-	public void parseMediaTypesWithAndWithoutDoubleQuotedCommas() {
-		String s = "foo/bar;param=\"s,\", text/x-c";
-		List<MediaType> mediaTypes = MediaType.parseMediaTypes(s);
-		assertEquals("Invalid amount of media types", 2, mediaTypes.size());
-		assertEquals("Comma should be part of the media type", "foo/bar;param=\"s,\"", mediaTypes.get(0).toString());
-	}
-
-	// SPR-17459
-	@Test
-	public void parseMediaTypesIgnoreEscapedDoubleQuoteWithinDoubleQuotes() {
-		String s = "foo/bar;param=\"a\\\"b,c\"";
-		List<MediaType> mediaTypes = MediaType.parseMediaTypes(s);
-		assertEquals("Invalid amount of media types", 1, mediaTypes.size());
-		assertEquals("Escaped quote within quotes should be ignored when considering comma tokenization", s, mediaTypes.get(0).toString());
-	}
-
-	// SPR-17459
-	@Test
-	public void parseMediaTypesIgnoreEscapedBackslash() {
-		String s = "foo/bar;param=\"\\\\\"";
-		List<MediaType> mediaTypes = MediaType.parseMediaTypes(s);
-		assertEquals("Invalid amount of media types", 1, mediaTypes.size());
-		assertEquals("Escaped quote within quotes should be ignored when considering comma tokenization", s, mediaTypes.get(0).toString());
-
-		s = "foo/bar;param=\"\\,\\\"";
-		mediaTypes = MediaType.parseMediaTypes(s);
-		assertEquals("Invalid amount of media types", 1, mediaTypes.size());
-		assertEquals("Escaped quote within quotes should be ignored when considering comma tokenization", s, mediaTypes.get(0).toString());
-	}
-
 	@Test
 	public void compareTo() {
 		MediaType audioBasic = new MediaType("audio", "basic");