ui: Cleanup class/struct forward declarations

build/android/java_assertion_enabler/java/org/chromium/javaassertionenabler/AssertionEnabler.java

Index: build/android/java_assertion_enabler/java/org/chromium/javaassertionenabler/AssertionEnabler.java
diff --git a/build/android/java_assertion_enabler/java/org/chromium/javaassertionenabler/AssertionEnabler.java b/build/android/java_assertion_enabler/java/org/chromium/javaassertionenabler/AssertionEnabler.java
new file mode 100644
index 0000000000000000000000000000000000000000..e800a3941395b34a4afc96938c6dac999b3b86c4
--- /dev/null
+++ b/build/android/java_assertion_enabler/java/org/chromium/javaassertionenabler/AssertionEnabler.java
@@ -0,0 +1,108 @@
+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package org.chromium.javaassertionenabler;
+
+import com.google.common.io.ByteStreams;
+
+import org.objectweb.asm.ClassReader;
+import org.objectweb.asm.ClassVisitor;
+import org.objectweb.asm.ClassWriter;
+import org.objectweb.asm.MethodVisitor;
+import org.objectweb.asm.Opcodes;
+
+import java.io.BufferedInputStream;
+import java.io.BufferedOutputStream;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.util.Collections;
+import java.util.jar.JarEntry;
+import java.util.jar.JarFile;
+import java.util.jar.JarOutputStream;
+
+/**
+ * An application that enables Java ASSERT statements by modifying Java bytecode. It takes in a JAR
+ * file, modifies bytecode of classes that use ASSERT, and outputs the bytecode to a new JAR file.
+ */
+class AssertionEnabler {
+    static final String CLASS_FILE_SUFFIX = ".class";
+    static final String STATIC_INITIALIZER_NAME = "<clinit>";
+    static final String ASSERTION_DISABLED_NAME = "$assertionsDisabled";
+
+    static class AssertionEnablerVisitor extends ClassVisitor {
+        AssertionEnablerVisitor(ClassWriter writer) {
+            super(Opcodes.ASM5, writer);
+        }
+
+        @Override
+        public MethodVisitor visitMethod(final int access, final String name, String desc,
+                String signature, String[] exceptions) {
+            // Patch static initializer.
+            if ((access & Opcodes.ACC_STATIC) != 0 && name.equals(STATIC_INITIALIZER_NAME)) {
+                return new MethodVisitor(Opcodes.ASM5,
+                        super.visitMethod(access, name, desc, signature, exceptions)) {
+                    // The following bytecode is generated for each class with ASSERT statements:
+                    // 0: ldc #8 // class CLASSNAME
+                    // 2: invokevirtual #9 // Method java/lang/Class.desiredAssertionStatus:()Z
+                    // 5: ifne 12
+                    // 8: iconst_1
+                    // 9: goto 13
+                    // 12: iconst_0
+                    // 13: putstatic #2 // Field $assertionsDisabled:Z
+                    //
+                    // This function replaces line #13 to the following:
+                    // 13: pop
+                    // Consequently, $assertionsDisabled is assigned the default value FALSE.
+                    @Override
+                    public void visitFieldInsn(int opcode, String owner, String name, String desc) {
+                        if (opcode == Opcodes.PUTSTATIC && name.equals(ASSERTION_DISABLED_NAME)) {
+                            mv.visitInsn(Opcodes.POP);
+                        } else {
+                            super.visitFieldInsn(opcode, owner, name, desc);
+                        }
+                    }
+                };
+            }
+            return super.visitMethod(access, name, desc, signature, exceptions);
+        }
+    }
+
+    static void enableAssertionInJar(String inputJarPath, String outputJarPath) {
+        try (JarOutputStream outputStream = new JarOutputStream(
+                new BufferedOutputStream(new FileOutputStream(outputJarPath)))) {
+            JarFile jarFile = new JarFile(inputJarPath);
+            for (JarEntry entry : Collections.list(jarFile.entries())) {
+                try (BufferedInputStream inputStream = new BufferedInputStream(
+                        jarFile.getInputStream(entry))) {
+                    byte[] byteCode = ByteStreams.toByteArray(inputStream);
+
+                    if (entry.isDirectory() || !entry.getName().endsWith(CLASS_FILE_SUFFIX)) {
+                        outputStream.putNextEntry(entry);
+                        outputStream.write(byteCode);
+                        outputStream.closeEntry();
+                        continue;
+                    }
+                    ClassReader reader = new ClassReader(byteCode);
+                    ClassWriter writer = new ClassWriter(reader, 0);
+                    reader.accept(new AssertionEnablerVisitor(writer), 0);
+                    byte[] patchedByteCode = writer.toByteArray();
+                    outputStream.putNextEntry(new JarEntry(entry.getName()));
+                    outputStream.write(patchedByteCode);
+                    outputStream.closeEntry();
+                }
+            }
+        } catch (IOException e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+    public static void main(String[] args) {
+        if (args.length != 2) {
+            System.out.println("Incorrect number of arguments.");
+            System.out.println("Example usage: java_assertion_enabler input.jar output.jar");
+            System.exit(-1);
+        }
+        enableAssertionInJar(args[0], args[1]);
+    }
+}