Reimplement ModuleInfoReader.readModuleName

Glavo · Jan 17, 2024 · fed889c · fed889c
1 parent 6bd99be
commit fed889c
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Showing 3 changed files with 70 additions and 10 deletions.
diff --git a/src/main/java/org/glavo/japp/packer/ModuleInfoReader.java b/src/main/java/org/glavo/japp/packer/ModuleInfoReader.java
@@ -15,9 +15,12 @@
  */
 package org.glavo.japp.packer;
 
+import org.glavo.japp.packer.compressor.classfile.ClassFileReader;
+
 import java.io.IOException;
 import java.io.InputStream;
 import java.lang.module.ModuleDescriptor;
+import java.nio.ByteBuffer;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
@@ -32,11 +35,10 @@ public static String deriveAutomaticModuleName(String jarFileName) {
             throw new IllegalArgumentException(jarFileName);
         }
 
-        int end = jarFileName.length() - ".jar".length();
-
-        int start;
+        final int end = jarFileName.length() - ".jar".length();
 
-        for (start = 0; start < end; start++) {
+        int start = 0;
+        for (; start < end; start++) {
             if (jarFileName.charAt(start) != '.') {
                 break;
             }
@@ -46,7 +48,7 @@ public static String deriveAutomaticModuleName(String jarFileName) {
             throw new IllegalArgumentException(jarFileName);
         }
 
-        String name = jarFileName.substring(start, jarFileName.length() - ".jar".length());
+        String name = jarFileName.substring(start, end);
 
         // find first occurrence of -${NUMBER}. or -${NUMBER}$
         Matcher matcher = DASH_VERSION.matcher(name);
@@ -67,7 +69,10 @@ public static String deriveAutomaticModuleName(String jarFileName) {
     }
 
     public static String readModuleName(InputStream moduleInfo) throws IOException {
-        // TODO: Support Java 8
-        return ModuleDescriptor.read(moduleInfo).name();
+        String moduleName = new ClassFileReader(ByteBuffer.wrap(moduleInfo.readAllBytes())).getModuleName();
+        if (moduleName == null) {
+            throw new IOException();
+        }
+        return moduleName;
     }
 }
diff --git a/src/main/java/org/glavo/japp/packer/compressor/classfile/ClassFileReader.java b/src/main/java/org/glavo/japp/packer/compressor/classfile/ClassFileReader.java
@@ -20,10 +20,11 @@
 
 import java.io.IOException;
 import java.nio.ByteBuffer;
+import java.nio.ByteOrder;
 
 import static org.glavo.japp.classfile.ClassFile.*;
 
-final class ClassFileReader {
+public final class ClassFileReader {
     private final ByteBuffer buffer;
     final byte[] tags;
     final int[] positions;
@@ -39,7 +40,11 @@ final class ClassFileReader {
     final int thisClass;
     final int superClass;
 
-    ClassFileReader(ByteBuffer buffer) throws IOException {
+    private String moduleName;
+
+    public ClassFileReader(ByteBuffer buffer) throws IOException {
+        assert buffer.order() == ByteOrder.BIG_ENDIAN;
+
         this.buffer = buffer;
 
         int magic = buffer.getInt();
@@ -280,6 +285,16 @@ private void scanAttributes() throws IOException {
                     }
                     break;
                 }
+                case "Module": {
+                    int moduleNameIndex = readU2();
+                    skip(attributeLength - 2);
+
+                    if (tags[moduleNameIndex] == CONSTANT_Module) {
+                        int stringIndex = Short.toUnsignedInt(buffer.getShort(positions[moduleNameIndex]));
+                        moduleName = getString(stringIndex);
+                    }
+                    break;
+                }
                 default:
                     skip(attributeLength);
             }
@@ -356,4 +371,8 @@ private void scanElementValue() throws IOException {
                 throw new IOException(String.format("Unknown element value: 0x%02x", tag));
         }
     }
+
+    public String getModuleName() {
+        return moduleName;
+    }
 }
diff --git a/src/test/java/org/glavo/japp/packer/ModuleInfoReaderTest.java b/src/test/java/org/glavo/japp/packer/ModuleInfoReaderTest.java
@@ -15,12 +15,23 @@
  */
 package org.glavo.japp.packer;
 
+import com.github.luben.zstd.Zstd;
 import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+
+import java.io.ByteArrayInputStream;
+import java.io.File;
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.Map;
+import java.util.stream.Stream;
+import java.util.zip.ZipFile;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
 
 public final class ModuleInfoReaderTest {
-
     @Test
     public void deriveAutomaticModuleNameTest() {
         assertEquals("a", ModuleInfoReader.deriveAutomaticModuleName("a.jar"));
@@ -30,4 +41,29 @@ public void deriveAutomaticModuleNameTest() {
         assertEquals("a.b", ModuleInfoReader.deriveAutomaticModuleName("a-b-0.1.0.jar"));
         assertEquals("a.b", ModuleInfoReader.deriveAutomaticModuleName("a--b-0.1.0.jar"));
     }
+
+    static Stream<Arguments> readModuleNameTestArguments() {
+        return Map.of(
+                "org.junit.jupiter.api", Test.class,
+                "com.github.luben.zstd_jni", Zstd.class
+        ).entrySet().stream().map(entry -> {
+
+            byte[] moduleInfo;
+            try (ZipFile zipFile = new ZipFile(new File(entry.getValue().getProtectionDomain().getCodeSource().getLocation().toURI()))) {
+                try (InputStream inputStream = zipFile.getInputStream(zipFile.getEntry("module-info.class"))) {
+                    moduleInfo = inputStream.readAllBytes();
+                }
+            } catch (Exception e) {
+                throw new AssertionError(e);
+            }
+
+            return Arguments.of(entry.getKey(), moduleInfo);
+        });
+    }
+
+    @ParameterizedTest
+    @MethodSource("readModuleNameTestArguments")
+    public void readModuleNameTest(String moduleName, byte[] moduleInfo) throws IOException {
+        assertEquals(moduleName, ModuleInfoReader.readModuleName(new ByteArrayInputStream(moduleInfo)));
+    }
 }