Support multiple input jars (#553)

* Support multiple input jars

This is needed for FabricMC/fabric-loom#1354.

* Remove unnecessary null check in GuiController.reloadAll

* Remove outdated TODO

3 files changed, 37 insertions, 11 deletions

diff --git a/enigma/src/main/java/cuchaz/enigma/Enigma.java b/enigma/src/main/java/cuchaz/enigma/Enigma.java
index 414285d..315b5f6 100644
--- a/enigma/src/main/java/cuchaz/enigma/Enigma.java
+++ b/enigma/src/main/java/cuchaz/enigma/Enigma.java
@@ -57,15 +57,33 @@ public class Enigma {
         }
 
         public EnigmaProject openJar(Path path, ClassProvider libraryClassProvider, ProgressListener progress) throws IOException {
-                JarClassProvider jarClassProvider = new JarClassProvider(path);
+                return openJars(List.of(path), libraryClassProvider, progress);
+        }
+
+        public EnigmaProject openJars(List<Path> paths, ClassProvider libraryClassProvider, ProgressListener progress) throws IOException {
+                ClassProvider jarClassProvider = getJarClassProvider(paths);
                 ClassProvider classProvider = new CachingClassProvider(new CombiningClassProvider(jarClassProvider, libraryClassProvider));
-                Set<String> scope = jarClassProvider.getClassNames();
+                Set<String> scope = Set.copyOf(jarClassProvider.getClassNames());
 
                 JarIndex index = JarIndex.empty();
                 ClassProvider classProviderWithFrames = index.indexJar(scope, classProvider, progress);
                 services.get(JarIndexerService.TYPE).forEach(indexer -> indexer.acceptJar(scope, classProviderWithFrames, index));
 
-                return new EnigmaProject(this, path, classProvider, index, Utils.zipSha1(path));
+                return new EnigmaProject(this, paths, classProvider, index, Utils.zipSha1(paths.toArray(new Path[0])));
+        }
+
+        private ClassProvider getJarClassProvider(List<Path> jars) throws IOException {
+                if (jars.size() == 1) {
+                        return new JarClassProvider(jars.get(0));
+                }
+
+                var classProviders = new ClassProvider[jars.size()];
+
+                for (int i = 0; i < jars.size(); i++) {
+                        classProviders[i] = new JarClassProvider(jars.get(i));
+                }
+
+                return new CombiningClassProvider(classProviders);
         }
 
         public EnigmaProfile getProfile() {
diff --git a/enigma/src/main/java/cuchaz/enigma/EnigmaProject.java b/enigma/src/main/java/cuchaz/enigma/EnigmaProject.java
index f9db4d1..1051f45 100644
--- a/enigma/src/main/java/cuchaz/enigma/EnigmaProject.java
+++ b/enigma/src/main/java/cuchaz/enigma/EnigmaProject.java
@@ -48,17 +48,17 @@ import cuchaz.enigma.utils.I18n;
 public class EnigmaProject {
         private final Enigma enigma;
 
-        private final Path jarPath;
+        private final List<Path> jarPaths;
         private final ClassProvider classProvider;
         private final JarIndex jarIndex;
         private final byte[] jarChecksum;
 
         private EntryRemapper mapper;
 
-        public EnigmaProject(Enigma enigma, Path jarPath, ClassProvider classProvider, JarIndex jarIndex, byte[] jarChecksum) {
+        public EnigmaProject(Enigma enigma, List<Path> jarPaths, ClassProvider classProvider, JarIndex jarIndex, byte[] jarChecksum) {
                 Preconditions.checkArgument(jarChecksum.length == 20);
                 this.enigma = enigma;
-                this.jarPath = jarPath;
+                this.jarPaths = List.copyOf(jarPaths);
                 this.classProvider = classProvider;
                 this.jarIndex = jarIndex;
                 this.jarChecksum = jarChecksum;
@@ -78,8 +78,8 @@ public class EnigmaProject {
                 return enigma;
         }
 
-        public Path getJarPath() {
-                return jarPath;
+        public List<Path> getJarPaths() {
+                return jarPaths;
         }
 
         public ClassProvider getClassProvider() {
diff --git a/enigma/src/main/java/cuchaz/enigma/utils/Utils.java b/enigma/src/main/java/cuchaz/enigma/utils/Utils.java
index 081c941..a1926a8 100644
--- a/enigma/src/main/java/cuchaz/enigma/utils/Utils.java
+++ b/enigma/src/main/java/cuchaz/enigma/utils/Utils.java
@@ -28,6 +28,7 @@ import java.util.function.Supplier;
 import java.util.zip.ZipEntry;
 import java.util.zip.ZipFile;
 
+import com.google.common.base.Preconditions;
 import com.google.common.io.CharStreams;
 
 public class Utils {
@@ -53,7 +54,8 @@ public class Utils {
                 }
         }
 
-        public static byte[] zipSha1(Path path) throws IOException {
+        public static byte[] zipSha1(Path... paths) throws IOException {
+                Preconditions.checkArgument(paths.length >= 1, "Must provide at least one zip");
                 MessageDigest digest;
 
                 try {
@@ -63,6 +65,14 @@ public class Utils {
                         throw new RuntimeException(e);
                 }
 
+                for (Path path : paths) {
+                        appendZipSha1(digest, path);
+                }
+
+                return digest.digest();
+        }
+
+        private static void appendZipSha1(MessageDigest digest, Path path) throws IOException {
                 try (ZipFile zip = new ZipFile(path.toFile())) {
                         List<? extends ZipEntry> entries = Collections.list(zip.entries());
                         // only compare classes (some implementations may not generate directory entries)
@@ -83,8 +93,6 @@ public class Utils {
                                 }
                         }
                 }
-
-                return digest.digest();
         }
 
         public static void withLock(Lock l, Runnable op) {