Improve ImageName/ImageReference parse performance

Update `ImageName` and `ImageReference` to use distinct regex patterns
to parse specific parts of the value. Prior to this commit a single
regex pattern was used which could hang given certain input strings.

Fixes gh-23115

Author: philwebb

spring-boot-project/spring-boot-tools/spring-boot-buildpack-platform/src/main/java/org/springframework/boot/buildpack/platform/docker/type/ImageName.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2020 the original author or authors.
+ * Copyright 2012-2021 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.
@@ -16,9 +16,6 @@
 
 package org.springframework.boot.buildpack.platform.docker.type;
 
-import java.util.regex.Matcher;
-import java.util.regex.Pattern;
-
 import org.springframework.util.Assert;
 
 /**
@@ -32,8 +29,6 @@
  */
 public class ImageName {
 
-	private static final Pattern PATTERN = Regex.IMAGE_NAME.compile();
-
 	private static final String DEFAULT_DOMAIN = "docker.io";
 
 	private static final String OFFICIAL_REPOSITORY_NAME = "library";
@@ -132,12 +127,22 @@ private String getNameWithDefaultPath(String domain, String name) {
 	 */
 	public static ImageName of(String value) {
 		Assert.hasText(value, "Value must not be empty");
-		Matcher matcher = PATTERN.matcher(value);
-		Assert.isTrue(matcher.matches(),
+		String domain = parseDomain(value);
+		String path = (domain != null) ? value.substring(domain.length() + 1) : value;
+		Assert.isTrue(Regex.PATH.matcher(path).matches(),
 				() -> "Unable to parse name \"" + value + "\". "
 						+ "Image name must be in the form '[domainHost:port/][path/]name', "
 						+ "with 'path' and 'name' containing only [a-z0-9][.][_][-]");
-		return new ImageName(matcher.group("domain"), matcher.group("path"));
+		return new ImageName(domain, path);
+	}
+
+	static String parseDomain(String value) {
+		int firstSlash = value.indexOf('/');
+		String candidate = (firstSlash != -1) ? value.substring(0, firstSlash) : null;
+		if (candidate != null && Regex.DOMAIN.matcher(candidate).matches()) {
+			return candidate;
+		}
+		return null;
 	}
 
 }

spring-boot-project/spring-boot-tools/spring-boot-buildpack-platform/src/main/java/org/springframework/boot/buildpack/platform/docker/type/ImageReference.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2020 the original author or authors.
+ * Copyright 2012-2021 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.
@@ -33,8 +33,6 @@
  */
 public final class ImageReference {
 
-	private static final Pattern PATTERN = Regex.IMAGE_REFERENCE.compile();
-
 	private static final Pattern JAR_VERSION_PATTERN = Pattern.compile("^(.*)(\\-\\d+)$");
 
 	private static final String LATEST = "latest";
@@ -225,13 +223,36 @@ public static ImageReference random(String prefix, int randomLength) {
 	 */
 	public static ImageReference of(String value) {
 		Assert.hasText(value, "Value must not be null");
-		Matcher matcher = PATTERN.matcher(value);
-		Assert.isTrue(matcher.matches(),
+		String domain = ImageName.parseDomain(value);
+		String path = (domain != null) ? value.substring(domain.length() + 1) : value;
+		String digest = null;
+		int digestSplit = path.indexOf("@");
+		if (digestSplit != -1) {
+			String remainder = path.substring(digestSplit + 1);
+			Matcher matcher = Regex.DIGEST.matcher(remainder);
+			if (matcher.find()) {
+				digest = remainder.substring(0, matcher.end());
+				remainder = remainder.substring(matcher.end());
+				path = path.substring(0, digestSplit) + remainder;
+			}
+		}
+		String tag = null;
+		int tagSplit = path.lastIndexOf(":");
+		if (tagSplit != -1) {
+			String remainder = path.substring(tagSplit + 1);
+			Matcher matcher = Regex.TAG.matcher(remainder);
+			if (matcher.find()) {
+				tag = remainder.substring(0, matcher.end());
+				remainder = remainder.substring(matcher.end());
+				path = path.substring(0, tagSplit) + remainder;
+			}
+		}
+		Assert.isTrue(Regex.PATH.matcher(path).matches(),
 				() -> "Unable to parse image reference \"" + value + "\". "
 						+ "Image reference must be in the form '[domainHost:port/][path/]name[:tag][@digest]', "
 						+ "with 'path' and 'name' containing only [a-z0-9][.][_][-]");
-		ImageName name = new ImageName(matcher.group("domain"), matcher.group("path"));
-		return new ImageReference(name, matcher.group("tag"), matcher.group("digest"));
+		ImageName name = new ImageName(domain, path);
+		return new ImageReference(name, tag, digest);
 	}
 
 	/**

spring-boot-project/spring-boot-tools/spring-boot-buildpack-platform/src/main/java/org/springframework/boot/buildpack/platform/docker/type/Regex.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2020 the original author or authors.
+ * Copyright 2012-2021 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.
@@ -36,15 +36,15 @@
  */
 final class Regex implements CharSequence {
 
-	private static final Regex DOMAIN;
+	static final Pattern DOMAIN;
 	static {
 		Regex component = Regex.oneOf("[a-zA-Z0-9]", "[a-zA-Z0-9][a-zA-Z0-9-]*[a-zA-Z0-9]");
 		Regex dotComponent = Regex.group("[.]", component);
 		Regex colonPort = Regex.of("[:][0-9]+");
 		Regex dottedDomain = Regex.group(component, dotComponent.oneOrMoreTimes());
 		Regex dottedDomainAndPort = Regex.group(component, dotComponent.oneOrMoreTimes(), colonPort);
 		Regex nameAndPort = Regex.group(component, colonPort);
-		DOMAIN = Regex.oneOf(dottedDomain, nameAndPort, dottedDomainAndPort, "localhost");
+		DOMAIN = Regex.oneOf(dottedDomain, nameAndPort, dottedDomainAndPort, "localhost").compile();
 	}
 
 	private static final Regex PATH_COMPONENT;
@@ -55,36 +55,18 @@ final class Regex implements CharSequence {
 		PATH_COMPONENT = Regex.of(segment, Regex.group(separatedSegment).zeroOrOnce());
 	}
 
-	private static final Regex PATH;
+	static final Pattern PATH;
 	static {
 		Regex component = PATH_COMPONENT;
 		Regex slashComponent = Regex.group("[/]", component);
 		Regex slashComponents = Regex.group(slashComponent.oneOrMoreTimes());
-		PATH = Regex.of(component, slashComponents.zeroOrOnce());
+		PATH = Regex.of(component, slashComponents.zeroOrOnce()).compile();
 	}
 
-	static final Regex IMAGE_NAME;
-	static {
-		Regex domain = DOMAIN.capturedAs("domain");
-		Regex domainSlash = Regex.group(domain, "[/]");
-		Regex path = PATH.capturedAs("path");
-		Regex optionalDomainSlash = domainSlash.zeroOrOnce();
-		IMAGE_NAME = Regex.of(optionalDomainSlash, path);
-	}
-
-	private static final Regex TAG_REGEX = Regex.of("[\\w][\\w.-]{0,127}");
-
-	private static final Regex DIGEST_REGEX = Regex
-			.of("[A-Za-z][A-Za-z0-9]*(?:[-_+.][A-Za-z][A-Za-z0-9]*)*[:][[A-Fa-f0-9]]{32,}");
+	static final Pattern TAG = Regex.of("^[\\w][\\w.-]{0,127}").compile();
 
-	static final Regex IMAGE_REFERENCE;
-	static {
-		Regex tag = TAG_REGEX.capturedAs("tag");
-		Regex digest = DIGEST_REGEX.capturedAs("digest");
-		Regex atDigest = Regex.group("[@]", digest);
-		Regex colonTag = Regex.group("[:]", tag);
-		IMAGE_REFERENCE = Regex.of(IMAGE_NAME, colonTag.zeroOrOnce(), atDigest.zeroOrOnce());
-	}
+	static final Pattern DIGEST = Regex.of("^[A-Za-z][A-Za-z0-9]*(?:[-_+.][A-Za-z][A-Za-z0-9]*)*[:][[A-Fa-f0-9]]{32,}")
+			.compile();
 
 	private final String value;
 
@@ -100,10 +82,6 @@ private Regex zeroOrOnce() {
 		return new Regex(this.value + "?");
 	}
 
-	private Regex capturedAs(String name) {
-		return new Regex("(?<" + name + ">" + this + ")");
-	}
-
 	Pattern compile() {
 		return Pattern.compile("^" + this.value + "$");
 	}

spring-boot-project/spring-boot-tools/spring-boot-buildpack-platform/src/test/java/org/springframework/boot/buildpack/platform/docker/type/ImageReferenceTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2020 the original author or authors.
+ * Copyright 2012-2021 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.
@@ -171,6 +171,14 @@ void ofImageNameTagAndDigest() {
 				"docker.io/library/ubuntu:bionic@sha256:6e9f67fa63b0323e9a1e587fd71c561ba48a034504fb804fd26fd8800039835d");
 	}
 
+	@Test
+	void ofWhenHasIllegalCharacter() {
+		assertThatIllegalArgumentException()
+				.isThrownBy(() -> ImageReference
+						.of("registry.example.com/example/example-app:1.6.0-dev.2.uncommitted+wip.foo.c75795d"))
+				.withMessageContaining("Unable to parse image reference");
+	}
+
 	@Test
 	void forJarFile() {
 		assertForJarFile("spring-boot.2.0.0.BUILD-SNAPSHOT.jar", "library/spring-boot", "2.0.0.BUILD-SNAPSHOT");