From 421d58695377b6464bc8eec73572a72e5e645201 Mon Sep 17 00:00:00 2001
From: anastasia <lubennikovaav@gmail.com>
Date: Wed, 28 Apr 2021 12:57:52 +0300
Subject: [PATCH] code cleanup for XLogRecord decoding

---
 pageserver/src/waldecoder.rs   |  6 +++---
 pageserver/src/walredo.rs      |  4 ++--
 postgres_ffi/src/xlog_utils.rs | 24 +++++++++++++-----------
 3 files changed, 18 insertions(+), 16 deletions(-)

diff --git a/pageserver/src/waldecoder.rs b/pageserver/src/waldecoder.rs
index 4327d1763e..4b9c8da62f 100644
--- a/pageserver/src/waldecoder.rs
+++ b/pageserver/src/waldecoder.rs
@@ -1,7 +1,7 @@
 use crate::pg_constants;
 use bytes::{Buf, BufMut, Bytes, BytesMut};
 use log::*;
-use postgres_ffi::xlog_utils;
+use postgres_ffi::xlog_utils::XLogRecord;
 use std::cmp::min;
 use std::str;
 use thiserror::Error;
@@ -337,7 +337,7 @@ pub struct DecodedWALRecord {
 fn is_xlog_switch_record(rec: &Bytes) -> bool {
     let mut buf = rec.clone();
 
-    let xlogrec = xlog_utils::parse_xlog_record(&mut buf);
+    let xlogrec = XLogRecord::from_bytes(&mut buf);
     xlogrec.xl_info == pg_constants::XLOG_SWITCH && xlogrec.xl_rmid == pg_constants::RM_XLOG_ID
 }
 
@@ -431,7 +431,7 @@ pub fn decode_wal_record(record: Bytes) -> DecodedWALRecord {
     // 1. Parse XLogRecord struct
 
     // FIXME: assume little-endian here
-    let xlogrec = xlog_utils::parse_xlog_record(&mut buf);
+    let xlogrec = XLogRecord::from_bytes(&mut buf);
 
     trace!(
         "decode_wal_record xl_rmid = {} xl_info = {}",
diff --git a/pageserver/src/walredo.rs b/pageserver/src/walredo.rs
index 1df386e447..70858bc9f0 100644
--- a/pageserver/src/walredo.rs
+++ b/pageserver/src/walredo.rs
@@ -38,7 +38,7 @@ use crate::page_cache::BufferTag;
 use crate::page_cache::WALRecord;
 use crate::ZTimelineId;
 use crate::{pg_constants, PageServerConf};
-use postgres_ffi::xlog_utils;
+use postgres_ffi::xlog_utils::{XLogRecord};
 
 static TIMEOUT: Duration = Duration::from_secs(20);
 
@@ -243,7 +243,7 @@ impl WalRedoManagerInternal {
 
                 // 1. Parse XLogRecord struct
                 // FIXME: refactor to avoid code duplication.
-                let xlogrec = xlog_utils::parse_xlog_record(&mut buf);
+                let xlogrec = XLogRecord::from_bytes(&mut buf);
 
                 //move to main data
                 // TODO probably, we should store some records in our special format
diff --git a/postgres_ffi/src/xlog_utils.rs b/postgres_ffi/src/xlog_utils.rs
index a2ccfb64e3..5e38294b1f 100644
--- a/postgres_ffi/src/xlog_utils.rs
+++ b/postgres_ffi/src/xlog_utils.rs
@@ -281,16 +281,18 @@ pub struct XLogRecord {
     pub xl_crc: u32,
 }
 
-pub fn parse_xlog_record(buf: &mut Bytes) -> XLogRecord {
-    XLogRecord {
-        xl_tot_len: buf.get_u32_le(),
-        xl_xid: buf.get_u32_le(),
-        xl_prev: buf.get_u64_le(),
-        xl_info: buf.get_u8(),
-        xl_rmid: buf.get_u8(),
-        xl_crc: {
-            buf.advance(2);
-            buf.get_u32_le()
-        },
+impl XLogRecord {
+    pub fn from_bytes(buf: &mut Bytes) -> XLogRecord {
+        XLogRecord {
+            xl_tot_len: buf.get_u32_le(),
+            xl_xid: buf.get_u32_le(),
+            xl_prev: buf.get_u64_le(),
+            xl_info: buf.get_u8(),
+            xl_rmid: buf.get_u8(),
+            xl_crc: {
+                buf.advance(2);
+                buf.get_u32_le()
+            },
+        }
     }
 }