Add support for AAR files

This adds support for comparing AAR files. The embedded classes.jar
is simply extracted and then treated as if it was the original jar
file.

This also adds a test suite.

Fix: #1

com.io7m.scando.cmdline/pom.xml

@@ -22,6 +22,14 @@
       <groupId>com.beust</groupId>
       <artifactId>jcommander</artifactId>
     </dependency>
+    <dependency>
+      <groupId>commons-io</groupId>
+      <artifactId>commons-io</artifactId>
+    </dependency>
+    <dependency>
+      <groupId>commons-codec</groupId>
+      <artifactId>commons-codec</artifactId>
+    </dependency>
     <dependency>
       <groupId>com.github.siom79.japicmp</groupId>
       <artifactId>japicmp</artifactId>

com.io7m.scando.cmdline/src/main/java/com/io7m/scando/cmdline/Main.java

@@ -31,14 +31,27 @@
 import japicmp.util.Optional;
 import japicmp.versioning.SemanticVersion;
 import japicmp.versioning.Version;
+import org.apache.commons.codec.binary.Hex;
+import org.apache.commons.io.FilenameUtils;
 
 import java.io.BufferedWriter;
+import java.io.File;
+import java.io.IOException;
+import java.io.InputStream;
+import java.nio.file.FileSystem;
 import java.nio.file.Files;
 import java.nio.file.Path;
+import java.security.MessageDigest;
+import java.security.NoSuchAlgorithmException;
 import java.util.Collections;
 import java.util.List;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
+import java.util.zip.ZipEntry;
+import java.util.zip.ZipFile;
+
+import static java.nio.file.StandardCopyOption.ATOMIC_MOVE;
+import static java.nio.file.StandardCopyOption.REPLACE_EXISTING;
 
 public final class Main
 {
@@ -63,28 +76,28 @@ public static final class Parameters
 
     @Parameter(
       names = "--oldJar",
-      description = "The old jar file",
+      description = "The old jar/aar file",
       required = true
     )
     private Path oldJarPath;
 
     @Parameter(
       names = "--oldJarVersion",
-      description = "The old jar version",
+      description = "The old jar/aar version",
       required = true
     )
     private String oldJarVersion;
 
     @Parameter(
       names = "--newJar",
-      description = "The new jar file",
+      description = "The new jar/aar file",
       required = true
     )
     private Path newJarPath;
 
     @Parameter(
       names = "--newJarVersion",
-      description = "The new jar version",
+      description = "The new jar/aar version",
       required = true
     )
     private String newJarVersion;
@@ -124,7 +137,7 @@ private static SemanticVersion semanticVersionOf(
     );
   }
 
-  public static void main(
+  public static int mainExitless(
     final String[] args)
     throws Exception
   {
@@ -140,13 +153,13 @@ public static void main(
 
       if (parameters.help) {
         commander.usage();
-        System.exit(0);
+        return 0;
       }
 
     } catch (final Exception e) {
       System.err.println("ERROR: " + e.getMessage());
       System.err.println("INFO: Try --help for usage information");
-      System.exit(1);
+      return 1;
     }
 
     parameters.newJarPath = parameters.newJarPath.toAbsolutePath();
@@ -162,14 +175,33 @@ public static void main(
     final SemanticVersion oldJarVersionValue =
       semanticVersionOf(new Version(parameters.oldJarVersion));
 
+    if (hashOf(parameters.oldJarPath).equals(hashOf(parameters.newJarPath))) {
+      System.err.println("INFO: The input files are identical; any version number change is acceptable");
+      return 0;
+    }
+
+    final File oldTargetFile;
+    if (parameters.oldJarPath.toString().endsWith(".aar")) {
+      oldTargetFile = unpackAAR(parameters.oldJarPath);
+    } else {
+      oldTargetFile = parameters.oldJarPath.toFile();
+    }
+
+    final File newTargetFile;
+    if (parameters.newJarPath.toString().endsWith(".aar")) {
+      newTargetFile = unpackAAR(parameters.newJarPath);
+    } else {
+      newTargetFile = parameters.newJarPath.toFile();
+    }
+
     final JApiCmpArchive oldArchives =
       new JApiCmpArchive(
-        parameters.oldJarPath.toFile(),
+        oldTargetFile,
         oldJarVersionValue.toString()
       );
     final JApiCmpArchive newArchives =
       new JApiCmpArchive(
-        parameters.newJarPath.toFile(),
+        newTargetFile,
         newJarVersionValue.toString()
       );
 
@@ -182,19 +214,7 @@ public static void main(
     options.setNewArchives(Collections.singletonList(newArchives));
 
     if (parameters.excludeList != null) {
-      try (Stream<String> lineStream = Files.lines(parameters.excludeList)) {
-        final List<String> lines = lineStream.collect(Collectors.toList());
-        for (final String line : lines) {
-          final String lineTrimmed = line.trim();
-          if (lineTrimmed.isEmpty()) {
-            continue;
-          }
-          if (lineTrimmed.startsWith("#")) {
-            continue;
-          }
-          options.addExcludeFromArgument(Optional.of(lineTrimmed), true);
-        }
-      }
+      loadExcludeList(parameters, options);
     }
 
     final JarArchiveComparatorOptions comparatorOptions =
@@ -206,15 +226,86 @@ public static void main(
 
     writeReports(options, jApiClasses, parameters, oldArchives, newArchives);
 
-    System.exit(
-      runSemanticVersionCheck(
-        jApiClasses,
-        newJarVersionValue,
-        oldJarVersionValue
-      )
+    return runSemanticVersionCheck(
+      jApiClasses,
+      newJarVersionValue,
+      oldJarVersionValue
     );
   }
 
+  private static String hashOf(final Path path)
+    throws IOException, NoSuchAlgorithmException
+  {
+    final MessageDigest digest = MessageDigest.getInstance("SHA-256");
+    try (InputStream stream = Files.newInputStream(path)) {
+      final byte[] buffer = new byte[4096];
+      while (true) {
+        final int r = stream.read(buffer);
+        if (r == -1) {
+          break;
+        }
+        digest.update(buffer, 0, r);
+      }
+    }
+    return Hex.encodeHexString(digest.digest());
+  }
+
+  public static void main(
+    final String[] args)
+    throws Exception
+  {
+    System.exit(mainExitless(args));
+  }
+
+  private static void loadExcludeList(
+    final Parameters parameters,
+    final Options options)
+    throws IOException
+  {
+    try (Stream<String> lineStream = Files.lines(parameters.excludeList)) {
+      final List<String> lines = lineStream.collect(Collectors.toList());
+      for (final String line : lines) {
+        final String lineTrimmed = line.trim();
+        if (lineTrimmed.isEmpty()) {
+          continue;
+        }
+        if (lineTrimmed.startsWith("#")) {
+          continue;
+        }
+        options.addExcludeFromArgument(Optional.of(lineTrimmed), true);
+      }
+    }
+  }
+
+  private static File unpackAAR(
+    final Path original)
+    throws IOException
+  {
+    final String filenameWithoutExtension =
+      FilenameUtils.removeExtension(original.toString());
+    final String newFilename =
+      String.format("%s.jar", filenameWithoutExtension);
+    final String newFilenameTmp =
+      String.format("%s.jar.tmp", filenameWithoutExtension);
+    final FileSystem fileSystem =
+      original.getFileSystem();
+    final Path output =
+      fileSystem.getPath(newFilename);
+    final Path outputTmp =
+      fileSystem.getPath(newFilenameTmp);
+
+    System.err.printf("INFO: Unpacking %s -> %s%n", original, newFilename);
+
+    try (ZipFile file = new ZipFile(original.toFile())) {
+      final ZipEntry entry = file.getEntry("classes.jar");
+      try (InputStream stream = file.getInputStream(entry)) {
+        Files.copy(stream, outputTmp);
+        Files.move(outputTmp, output, REPLACE_EXISTING, ATOMIC_MOVE);
+      }
+    }
+    return output.toFile();
+  }
+
   private static int runSemanticVersionCheck(
     final List<JApiClass> jApiClasses,
     final SemanticVersion newJarVersionValue,

com.io7m.scando.tests/pom.xml

@@ -0,0 +1,49 @@
+<?xml version="1.0" encoding="UTF-8"?>
+
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+
+  <modelVersion>4.0.0</modelVersion>
+
+  <parent>
+    <groupId>com.io7m.scando</groupId>
+    <artifactId>com.io7m.scando</artifactId>
+    <version>0.0.3</version>
+  </parent>
+
+  <artifactId>com.io7m.scando.tests</artifactId>
+  <description>Ultra-minimalist semantic versioning checker (Test suite)</description>
+  <name>com.io7m.scando.tests</name>
+  <url>https://www.github.com/io7m/scando</url>
+
+  <properties>
+    <mdep.analyze.skip>true</mdep.analyze.skip>
+  </properties>
+
+  <dependencies>
+    <dependency>
+      <groupId>${project.groupId}</groupId>
+      <artifactId>com.io7m.scando.cmdline</artifactId>
+      <version>${project.version}</version>
+    </dependency>
+
+    <dependency>
+      <groupId>org.slf4j</groupId>
+      <artifactId>slf4j-api</artifactId>
+    </dependency>
+    <dependency>
+      <groupId>ch.qos.logback</groupId>
+      <artifactId>logback-classic</artifactId>
+    </dependency>
+    <dependency>
+      <groupId>org.junit.jupiter</groupId>
+      <artifactId>junit-jupiter-api</artifactId>
+    </dependency>
+    <dependency>
+      <groupId>org.junit.jupiter</groupId>
+      <artifactId>junit-jupiter-engine</artifactId>
+    </dependency>
+  </dependencies>
+
+</project>