fn on_checkpoint()

in src/lib.rs [831:866]

• 30 lines of code
• 2 McCabe index (conditional complexity)

        fn on_checkpoint(
            &mut self,
            address: usize,
            len: usize,
            page_size: usize,
        ) -> Result<(), RuntimeError> {
            use libc::mincore;

            let mem_size = len * size_of::<usize>();

            let aligned_address = address / page_size * page_size;
            let aligned_mem_size = mem_size + (address - aligned_address);

            // buf needs to be at least (aligned_mem_size + page_size - 1) / page_size
            let mut buf: Vec<u8> = vec![0; aligned_mem_size.div_ceil(page_size)];
            assert_eq!(
                unsafe {
                    mincore(
                        aligned_address as *mut std::ffi::c_void,
                        aligned_mem_size,
                        buf.as_mut_ptr().cast(),
                    )
                },
                0,
                "mincore did not return 0"
            );
            if buf.iter().any(|n| *n & 1 == 0) {
                trace!("Detected page fault");
                return Err(RuntimeError::PageFault);
            }

            self.set_next_checkpoint();
            self.completed_iter += 1;

            Ok(())
        }