replace-read-more.php

<?php
if ( ! function_exists( 'woocommerce_template_loop_add_to_cart' ) ) {

	function woocommerce_template_loop_add_to_cart( $args = array() ) {

		global $product;

		if ( !$product->is_in_stock() ) {
			echo '<a href="' . get_permalink() . '" class="button">Out of Stock</a>';
		} else {
			$defaults = array(
				'quantity' => 1,
				'class' => implode( ' ', array_filter( array(
					'button',
					'product_type_' . $product->product_type,
					$product->is_purchasable() && $product->is_in_stock() ? 'add_to_cart_button' : '',
					$product->supports( 'ajax_add_to_cart' ) ? 'ajax_add_to_cart' : ''
				) ) )
			);

			$args = apply_filters( 'woocommerce_loop_add_to_cart_args', wp_parse_args( $args, $defaults ), $product );

			wc_get_template( 'loop/add-to-cart.php', $args );
		}

	}
}