Show the source jar of a ClasspathResource

Update `TextResourceOrigin` so that it shows the source jar file
of a `ClasspathResource`.

Closes gh-23019

Author: philwebb

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/origin/JarUri.java

@@ -0,0 +1,82 @@
+/*
+ * Copyright 2012-2020 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.origin;
+
+import java.net.URI;
+
+/**
+ * Simple class that understands Jar URLs can can provide short descriptions.
+ *
+ * @author Phillip Webb
+ */
+final class JarUri {
+
+	private static final String JAR_SCHEME = "jar:";
+
+	private static final String JAR_EXTENSION = ".jar";
+
+	private final String uri;
+
+	private final String description;
+
+	private JarUri(String uri) {
+		this.uri = uri;
+		this.description = extractDescription(uri);
+	}
+
+	private String extractDescription(String uri) {
+		uri = uri.substring(JAR_SCHEME.length());
+		int firstDotJar = uri.indexOf(JAR_EXTENSION);
+		String firstJar = getFilename(uri.substring(0, firstDotJar + JAR_EXTENSION.length()));
+		uri = uri.substring(firstDotJar + JAR_EXTENSION.length());
+		int lastDotJar = uri.lastIndexOf(JAR_EXTENSION);
+		if (lastDotJar == -1) {
+			return firstJar;
+		}
+		return firstJar + uri.substring(0, lastDotJar + JAR_EXTENSION.length());
+	}
+
+	private String getFilename(String string) {
+		int lastSlash = string.lastIndexOf('/');
+		return (lastSlash == -1) ? string : string.substring(lastSlash + 1);
+	}
+
+	String getDescription() {
+		return this.description;
+	}
+
+	String getDescription(String existing) {
+		return existing + " from " + this.description;
+	}
+
+	@Override
+	public String toString() {
+		return this.uri;
+	}
+
+	static JarUri from(URI uri) {
+		return from(uri.toString());
+	}
+
+	static JarUri from(String uri) {
+		if (uri.startsWith(JAR_SCHEME) && uri.contains(JAR_EXTENSION)) {
+			return new JarUri(uri);
+		}
+		return null;
+	}
+
+}

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/origin/TextResourceOrigin.java

@@ -16,6 +16,9 @@
 
 package org.springframework.boot.origin;
 
+import java.io.IOException;
+
+import org.springframework.core.io.ClassPathResource;
 import org.springframework.core.io.Resource;
 import org.springframework.util.ObjectUtils;
 
@@ -91,13 +94,38 @@ public int hashCode() {
 	@Override
 	public String toString() {
 		StringBuilder result = new StringBuilder();
-		result.append((this.resource != null) ? this.resource.getDescription() : "unknown resource [?]");
+		result.append(getResourceDescription(this.resource));
 		if (this.location != null) {
-			result.append(":").append(this.location);
+			result.append(" - ").append(this.location);
 		}
 		return result.toString();
 	}
 
+	private String getResourceDescription(Resource resource) {
+		if (resource instanceof OriginTrackedResource) {
+			return getResourceDescription(((OriginTrackedResource) resource).getResource());
+		}
+		if (resource == null) {
+			return "unknown resource [?]";
+		}
+		if (resource instanceof ClassPathResource) {
+			return getResourceDescription((ClassPathResource) resource);
+		}
+		return resource.getDescription();
+	}
+
+	private String getResourceDescription(ClassPathResource resource) {
+		try {
+			JarUri jarUri = JarUri.from(resource.getURI());
+			if (jarUri != null) {
+				return jarUri.getDescription(resource.getDescription());
+			}
+		}
+		catch (IOException ex) {
+		}
+		return resource.getDescription();
+	}
+
 	/**
 	 * A location (line and column number) within the resource.
 	 */

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/origin/JarUriTests.java

@@ -0,0 +1,56 @@
+/*
+ * Copyright 2012-2020 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.origin;
+
+import org.junit.jupiter.api.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * @author pwebb
+ */
+class JarUriTests {
+
+	@Test
+	void describeBootInfClassesUri() {
+		JarUri uri = JarUri.from("jar:file:/home/user/project/target/project-0.0.1-SNAPSHOT.jar"
+				+ "!/BOOT-INF/classes!/application.properties");
+		assertThat(uri.getDescription()).isEqualTo("project-0.0.1-SNAPSHOT.jar");
+	}
+
+	@Test
+	void describeBootInfLibUri() {
+		JarUri uri = JarUri.from("jar:file:/home/user/project/target/project-0.0.1-SNAPSHOT.jar"
+				+ "!/BOOT-INF/lib/nested.jar!/application.properties");
+		assertThat(uri.getDescription()).isEqualTo("project-0.0.1-SNAPSHOT.jar!/BOOT-INF/lib/nested.jar");
+	}
+
+	@Test
+	void describeRegularJar() {
+		JarUri uri = JarUri
+				.from("jar:file:/home/user/project/target/project-0.0.1-SNAPSHOT.jar!/application.properties");
+		assertThat(uri.getDescription()).isEqualTo("project-0.0.1-SNAPSHOT.jar");
+	}
+
+	@Test
+	void getDescriptionMergedWithExisting() {
+		JarUri uri = JarUri.from("jar:file:/project-0.0.1-SNAPSHOT.jar!/application.properties");
+		assertThat(uri.getDescription("classpath: [application.properties]"))
+				.isEqualTo("classpath: [application.properties] from project-0.0.1-SNAPSHOT.jar");
+	}
+
+}

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/origin/TextResourceOriginTests.java

@@ -16,6 +16,10 @@
 
 package org.springframework.boot.origin;
 
+import java.io.IOException;
+import java.net.URI;
+import java.net.URISyntaxException;
+
 import org.junit.jupiter.api.Test;
 
 import org.springframework.boot.origin.TextResourceOrigin.Location;
@@ -95,14 +99,14 @@ void toStringReturnsNiceString() {
 		ClassPathResource resource = new ClassPathResource("foo.txt");
 		Location location = new Location(1, 2);
 		TextResourceOrigin origin = new TextResourceOrigin(resource, location);
-		assertThat(origin.toString()).isEqualTo("class path resource [foo.txt]:2:3");
+		assertThat(origin.toString()).isEqualTo("class path resource [foo.txt] - 2:3");
 	}
 
 	@Test
 	void toStringWhenResourceIsNullReturnsNiceString() {
 		Location location = new Location(1, 2);
 		TextResourceOrigin origin = new TextResourceOrigin(null, location);
-		assertThat(origin.toString()).isEqualTo("unknown resource [?]:2:3");
+		assertThat(origin.toString()).isEqualTo("unknown resource [?] - 2:3");
 	}
 
 	@Test
@@ -112,6 +116,27 @@ void toStringWhenLocationIsNullReturnsNiceString() {
 		assertThat(origin.toString()).isEqualTo("class path resource [foo.txt]");
 	}
 
+	@Test
+	void toStringWhenResourceIsClasspathResourceReturnsToStringWithJar() {
+		ClassPathResource resource = new ClassPathResource("foo.txt") {
+
+			@Override
+			public URI getURI() throws IOException {
+				try {
+					return new URI("jar:file:/home/user/project/target/project-0.0.1-SNAPSHOT.jar"
+							+ "!/BOOT-INF/classes!/foo.txt");
+				}
+				catch (URISyntaxException ex) {
+					throw new IllegalStateException(ex);
+				}
+			}
+
+		};
+		Location location = new Location(1, 2);
+		TextResourceOrigin origin = new TextResourceOrigin(resource, location);
+		assertThat(origin.toString()).isEqualTo("class path resource [foo.txt] from project-0.0.1-SNAPSHOT.jar - 2:3");
+	}
+
 	@Test
 	void locationEqualsAndHashCodeUsesLineAndColumn() {
 		Location location1 = new Location(1, 2);