Count lines of code (LOC) for JAR and AAR

Question

How do we count the number of lines of code in a Library file.

For eg, a Jar or AAR.

Note - CLOC is an awesome tool, but unfortunately, it doesn't process ".class" files.

Converting JAR -> DEX and decompile DEX -> code, is one way of doing it, but the precision could be lost during the conversion and decompilation.

Answer 1

In some cases, you might be able to get a rough idea idea of the number of lines, using the debug information in the dex file.

Using dexlib2, you could do something like:

public static void main(String[] args) throws IOException {
    DexFile dexFile = DexFileFactory.loadDexFile(args[0], 15);

    long lineCount = 0;

    for (ClassDef classDef: dexFile.getClasses()) {
        for (Method method: classDef.getMethods()) {
            MethodImplementation impl = method.getImplementation();
            if (impl != null) {
                for (DebugItem debugItem: impl.getDebugItems()) {
                    if (debugItem.getDebugItemType() == DebugItemType.LINE_NUMBER) {
                        lineCount++;
                    }
                }
            }
        }
    }

    System.out.println(String.format("%d lines", lineCount));
}

An alternative metric for comparing code size might be the number of instructions in a dex file. e.g.

public static void main(String[] args) throws IOException {
    DexFile dexFile = DexFileFactory.loadDexFile(args[0], 15);

    long instructionCount = 0;

    for (ClassDef classDef: dexFile.getClasses()) {
        for (Method method: classDef.getMethods()) {
            MethodImplementation impl = method.getImplementation();
            if (impl != null) {
                for (Instruction instruction: impl.getInstructions()) {
                    instructionCount++;
                }
            }
        }
    }

    System.out.println(String.format("%d instructions", instructionCount));
}