Function update_fill_method

src/manip.rs:158–186

(class_file: &mut Classfile)

}

unsafe fn update_fill_method(class_file: &mut Classfile) -> Result<(), String> {
    // Change existing fillInStackTrace to call stackParamFillInStackTrace(Thread) right after fillInStackTrace(0)
    let fill_meth_name_idx = utf8_const(class_file, "fillInStackTrace");
    // Get the code
    let curr_thread_ref_idx = method_ref_const(class_file, "java/lang/Thread", "currentThread", "()Ljava/lang/Thread;");
    let meth_ret_throwable_idx = utf8_const(class_file, "()Ljava/lang/Throwable;");
    let native_fill_meth_ref_idx = method_ref_const(class_file, "java/lang/Throwable", "fillInStackTrace", "(I)Ljava/lang/Throwable;");
    let new_native_fill_meth_ref_idx = method_ref_const(class_file,
                                                        "java/lang/Throwable",
                                                        "stackParamFillInStackTrace",
                                                        "(Ljava/lang/Thread;)Ljava/lang/Throwable;");
    let mut fill_meth = class_file.methods.iter_mut().find(|m| {
        m.name_index.idx == fill_meth_name_idx && m.descriptor_index.idx == meth_ret_throwable_idx
    }).ok_or("Cannot find fill method".to_string())?;
    let mut fill_meth_code = get_method_code_mut(&mut fill_meth)?;
    // Find the index of the invoke special
    let fill_invoke_idx = fill_meth_code.iter().position(|i| {
        match i {
            &Instruction::INVOKESPECIAL(ref idx) if *idx == native_fill_meth_ref_idx as u16 => true,
            _ => false
        }
    }).ok_or("Cannot find invoke of native fill".to_string())?;
    // Call mine afterwards. "this" is currently on the stack already. It takes the current thread,
    // so we grab that statically before calling so it is on the stack (current max stack of >= 2 is
    // still ok for us). Result is a throwable so the stack is left how we got it.
    fill_meth_code.insert(fill_invoke_idx + 1, Instruction::INVOKESTATIC(curr_thread_ref_idx as u16));
    fill_meth_code.insert(fill_invoke_idx + 2, Instruction::INVOKESPECIAL(new_native_fill_meth_ref_idx as u16));
    return Result::Ok(());
}

unsafe fn replace_our_trace_method(class_file: &mut Classfile) -> Result<(), String> {
    // Rename getOurStackTrace to $$stack_param$$getOurStackTrace, then create a new