Extract ModifiedClassPathClass logic

Extract classes from `ModifiedClassPathRunner` so that they can
be reused.

See gh-17491

Author: dreis2211

spring-boot-project/spring-boot-tools/spring-boot-test-support/src/main/java/org/springframework/boot/testsupport/runner/classpath/ModifiedClassPathClassLoader.java

@@ -0,0 +1,46 @@
+/*
+ * Copyright 2012-2019 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.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.boot.testsupport.runner.classpath;
+
+import java.net.URL;
+import java.net.URLClassLoader;
+
+/**
+ * Custom {@link URLClassLoader} that modifies the class path.
+ *
+ * @author Andy Wilkinson
+ * @author Christoph Dreis
+ * @see ModifiedClassPathClassLoaderFactory
+ */
+final class ModifiedClassPathClassLoader extends URLClassLoader {
+
+	private final ClassLoader junitLoader;
+
+	ModifiedClassPathClassLoader(URL[] urls, ClassLoader parent, ClassLoader junitLoader) {
+		super(urls, parent);
+		this.junitLoader = junitLoader;
+	}
+
+	@Override
+	public Class<?> loadClass(String name) throws ClassNotFoundException {
+		if (name.startsWith("org.junit") || name.startsWith("org.hamcrest")) {
+			return this.junitLoader.loadClass(name);
+		}
+		return super.loadClass(name);
+	}
+
+}

spring-boot-project/spring-boot-tools/spring-boot-test-support/src/main/java/org/springframework/boot/testsupport/runner/classpath/ModifiedClassPathClassLoaderFactory.java

@@ -0,0 +1,248 @@
+/*
+ * Copyright 2012-2019 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.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.boot.testsupport.runner.classpath;
+
+import java.io.File;
+import java.lang.management.ManagementFactory;
+import java.net.URISyntaxException;
+import java.net.URL;
+import java.net.URLClassLoader;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collections;
+import java.util.List;
+import java.util.jar.Attributes;
+import java.util.jar.JarFile;
+import java.util.regex.Pattern;
+import java.util.stream.Stream;
+
+import org.apache.maven.repository.internal.MavenRepositorySystemUtils;
+import org.eclipse.aether.DefaultRepositorySystemSession;
+import org.eclipse.aether.RepositorySystem;
+import org.eclipse.aether.artifact.DefaultArtifact;
+import org.eclipse.aether.collection.CollectRequest;
+import org.eclipse.aether.connector.basic.BasicRepositoryConnectorFactory;
+import org.eclipse.aether.graph.Dependency;
+import org.eclipse.aether.impl.DefaultServiceLocator;
+import org.eclipse.aether.repository.LocalRepository;
+import org.eclipse.aether.repository.RemoteRepository;
+import org.eclipse.aether.resolution.ArtifactResult;
+import org.eclipse.aether.resolution.DependencyRequest;
+import org.eclipse.aether.resolution.DependencyResult;
+import org.eclipse.aether.spi.connector.RepositoryConnectorFactory;
+import org.eclipse.aether.spi.connector.transport.TransporterFactory;
+import org.eclipse.aether.transport.http.HttpTransporterFactory;
+
+import org.springframework.core.annotation.MergedAnnotation;
+import org.springframework.core.annotation.MergedAnnotations;
+import org.springframework.util.AntPathMatcher;
+import org.springframework.util.StringUtils;
+
+/**
+ * A factory that creates a custom class loader with a modified class path that is used to
+ * both load the test class and as the thread context class loader while the test is being
+ * run.
+ *
+ * @author Andy Wilkinson
+ * @author Christoph Dreis
+ * @see ModifiedClassPathClassLoader
+ */
+final class ModifiedClassPathClassLoaderFactory {
+
+	private static final Pattern INTELLIJ_CLASSPATH_JAR_PATTERN = Pattern.compile(".*classpath(\\d+)?\\.jar");
+
+	private ModifiedClassPathClassLoaderFactory() {
+	}
+
+	static URLClassLoader createTestClassLoader(Class<?> testClass) {
+		ClassLoader classLoader = testClass.getClassLoader();
+		return new ModifiedClassPathClassLoader(processUrls(extractUrls(classLoader), testClass),
+				classLoader.getParent(), classLoader);
+	}
+
+	private static URL[] extractUrls(ClassLoader classLoader) {
+		List<URL> extractedUrls = new ArrayList<>();
+		doExtractUrls(classLoader).forEach((URL url) -> {
+			if (isManifestOnlyJar(url)) {
+				extractedUrls.addAll(extractUrlsFromManifestClassPath(url));
+			}
+			else {
+				extractedUrls.add(url);
+			}
+		});
+		return extractedUrls.toArray(new URL[0]);
+	}
+
+	private static Stream<URL> doExtractUrls(ClassLoader classLoader) {
+		if (classLoader instanceof URLClassLoader) {
+			return Stream.of(((URLClassLoader) classLoader).getURLs());
+		}
+		return Stream.of(ManagementFactory.getRuntimeMXBean().getClassPath().split(File.pathSeparator))
+				.map(ModifiedClassPathClassLoaderFactory::toURL);
+	}
+
+	private static URL toURL(String entry) {
+		try {
+			return new File(entry).toURI().toURL();
+		}
+		catch (Exception ex) {
+			throw new IllegalArgumentException(ex);
+		}
+	}
+
+	private static boolean isManifestOnlyJar(URL url) {
+		return isSurefireBooterJar(url) || isShortenedIntelliJJar(url);
+	}
+
+	private static boolean isSurefireBooterJar(URL url) {
+		return url.getPath().contains("surefirebooter");
+	}
+
+	private static boolean isShortenedIntelliJJar(URL url) {
+		String urlPath = url.getPath();
+		boolean isCandidate = INTELLIJ_CLASSPATH_JAR_PATTERN.matcher(urlPath).matches();
+		if (isCandidate) {
+			try {
+				Attributes attributes = getManifestMainAttributesFromUrl(url);
+				String createdBy = attributes.getValue("Created-By");
+				return createdBy != null && createdBy.contains("IntelliJ");
+			}
+			catch (Exception ex) {
+			}
+		}
+		return false;
+	}
+
+	private static List<URL> extractUrlsFromManifestClassPath(URL booterJar) {
+		List<URL> urls = new ArrayList<>();
+		try {
+			for (String entry : getClassPath(booterJar)) {
+				urls.add(new URL(entry));
+			}
+		}
+		catch (Exception ex) {
+			throw new RuntimeException(ex);
+		}
+		return urls;
+	}
+
+	private static String[] getClassPath(URL booterJar) throws Exception {
+		Attributes attributes = getManifestMainAttributesFromUrl(booterJar);
+		return StringUtils.delimitedListToStringArray(attributes.getValue(Attributes.Name.CLASS_PATH), " ");
+	}
+
+	private static Attributes getManifestMainAttributesFromUrl(URL url) throws Exception {
+		try (JarFile jarFile = new JarFile(new File(url.toURI()))) {
+			return jarFile.getManifest().getMainAttributes();
+		}
+	}
+
+	private static URL[] processUrls(URL[] urls, Class<?> testClass) {
+		MergedAnnotations annotations = MergedAnnotations.from(testClass, MergedAnnotations.SearchStrategy.EXHAUSTIVE);
+		ClassPathEntryFilter filter = new ClassPathEntryFilter(annotations.get(ClassPathExclusions.class));
+		List<URL> processedUrls = new ArrayList<>();
+		List<URL> additionalUrls = getAdditionalUrls(annotations.get(ClassPathOverrides.class));
+		processedUrls.addAll(additionalUrls);
+		for (URL url : urls) {
+			if (!filter.isExcluded(url)) {
+				processedUrls.add(url);
+			}
+		}
+		return processedUrls.toArray(new URL[0]);
+	}
+
+	private static List<URL> getAdditionalUrls(MergedAnnotation<ClassPathOverrides> annotation) {
+		if (!annotation.isPresent()) {
+			return Collections.emptyList();
+		}
+		return resolveCoordinates(annotation.getStringArray(MergedAnnotation.VALUE));
+	}
+
+	private static List<URL> resolveCoordinates(String[] coordinates) {
+		DefaultServiceLocator serviceLocator = MavenRepositorySystemUtils.newServiceLocator();
+		serviceLocator.addService(RepositoryConnectorFactory.class, BasicRepositoryConnectorFactory.class);
+		serviceLocator.addService(TransporterFactory.class, HttpTransporterFactory.class);
+		RepositorySystem repositorySystem = serviceLocator.getService(RepositorySystem.class);
+		DefaultRepositorySystemSession session = MavenRepositorySystemUtils.newSession();
+		LocalRepository localRepository = new LocalRepository(System.getProperty("user.home") + "/.m2/repository");
+		session.setLocalRepositoryManager(repositorySystem.newLocalRepositoryManager(session, localRepository));
+		CollectRequest collectRequest = new CollectRequest(null, Arrays.asList(
+				new RemoteRepository.Builder("central", "default", "https://repo.maven.apache.org/maven2").build()));
+
+		collectRequest.setDependencies(createDependencies(coordinates));
+		DependencyRequest dependencyRequest = new DependencyRequest(collectRequest, null);
+		try {
+			DependencyResult result = repositorySystem.resolveDependencies(session, dependencyRequest);
+			List<URL> resolvedArtifacts = new ArrayList<>();
+			for (ArtifactResult artifact : result.getArtifactResults()) {
+				resolvedArtifacts.add(artifact.getArtifact().getFile().toURI().toURL());
+			}
+			return resolvedArtifacts;
+		}
+		catch (Exception ignored) {
+			return Collections.emptyList();
+
+		}
+	}
+
+	private static List<Dependency> createDependencies(String[] allCoordinates) {
+		List<Dependency> dependencies = new ArrayList<>();
+		for (String coordinate : allCoordinates) {
+			dependencies.add(new Dependency(new DefaultArtifact(coordinate), null));
+		}
+		return dependencies;
+	}
+
+	/**
+	 * Filter for class path entries.
+	 */
+	private static final class ClassPathEntryFilter {
+
+		private final List<String> exclusions;
+
+		private final AntPathMatcher matcher = new AntPathMatcher();
+
+		private ClassPathEntryFilter(MergedAnnotation<ClassPathExclusions> annotation) {
+			this.exclusions = new ArrayList<>();
+			this.exclusions.add("log4j-*.jar");
+			if (annotation.isPresent()) {
+				this.exclusions.addAll(Arrays.asList(annotation.getStringArray(MergedAnnotation.VALUE)));
+			}
+		}
+
+		private boolean isExcluded(URL url) {
+			if (!"file".equals(url.getProtocol())) {
+				return false;
+			}
+			String name;
+			try {
+				name = new File(url.toURI()).getName();
+			}
+			catch (URISyntaxException ex) {
+				return false;
+			}
+			for (String exclusion : this.exclusions) {
+				if (this.matcher.match(exclusion, name)) {
+					return true;
+				}
+			}
+			return false;
+		}
+
+	}
+
+}