Line data    Source code

       1              : use bytes::BufMut;
       2              : use pageserver_api::reltag::RelTag;
       3              : use serde::Serialize;
       4              : use utils::bin_ser::BeSer;
       5              : use utils::lsn::Lsn;
       6              : 
       7              : ///
       8              : /// `RelTag` + block number (`blknum`) gives us a unique id of the page in the cluster.
       9              : ///
      10              : /// In Postgres `BufferTag` structure is used for exactly the same purpose.
      11              : /// [See more related comments here](https://github.com/postgres/postgres/blob/99c5852e20a0987eca1c38ba0c09329d4076b6a0/src/include/storage/buf_internals.h#L91).
      12              : ///
      13              : #[derive(Debug, PartialEq, Eq, PartialOrd, Ord, Clone, Copy, Serialize)]
      14              : pub(crate) struct BufferTag {
      15              :     pub rel: RelTag,
      16              :     pub blknum: u32,
      17              : }
      18              : 
      19            8 : pub(crate) fn build_begin_redo_for_block_msg(tag: BufferTag, buf: &mut Vec<u8>) {
      20            8 :     let len = 4 + 1 + 4 * 4;
      21            8 : 
      22            8 :     buf.put_u8(b'B');
      23            8 :     buf.put_u32(len as u32);
      24            8 : 
      25            8 :     tag.ser_into(buf)
      26            8 :         .expect("serialize BufferTag should always succeed");
      27            8 : }
      28              : 
      29            0 : pub(crate) fn build_push_page_msg(tag: BufferTag, base_img: &[u8], buf: &mut Vec<u8>) {
      30            0 :     assert!(base_img.len() == 8192);
      31              : 
      32            0 :     let len = 4 + 1 + 4 * 4 + base_img.len();
      33            0 : 
      34            0 :     buf.put_u8(b'P');
      35            0 :     buf.put_u32(len as u32);
      36            0 :     tag.ser_into(buf)
      37            0 :         .expect("serialize BufferTag should always succeed");
      38            0 :     buf.put(base_img);
      39            0 : }
      40              : 
      41           16 : pub(crate) fn build_apply_record_msg(endlsn: Lsn, rec: &[u8], buf: &mut Vec<u8>) {
      42           16 :     let len = 4 + 8 + rec.len();
      43           16 : 
      44           16 :     buf.put_u8(b'A');
      45           16 :     buf.put_u32(len as u32);
      46           16 :     buf.put_u64(endlsn.0);
      47           16 :     buf.put(rec);
      48           16 : }
      49              : 
      50            8 : pub(crate) fn build_get_page_msg(tag: BufferTag, buf: &mut Vec<u8>) {
      51            8 :     let len = 4 + 1 + 4 * 4;
      52            8 : 
      53            8 :     buf.put_u8(b'G');
      54            8 :     buf.put_u32(len as u32);
      55            8 :     tag.ser_into(buf)
      56            8 :         .expect("serialize BufferTag should always succeed");
      57            8 : }