From a362ab9169c063b5ff9fdf215e482dcc3d901123 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Arpad=20M=C3=BCller?= <arpad@neon.tech>
Date: Mon, 28 Aug 2023 10:27:12 +0200
Subject: [PATCH] Move VirtualFile::seek to inherent function

---
 .../src/tenant/storage_layer/delta_layer.rs   |  2 +-
 .../src/tenant/storage_layer/image_layer.rs   |  2 +-
 pageserver/src/virtual_file.rs                | 52 +++++++++----------
 3 files changed, 27 insertions(+), 29 deletions(-)

diff --git a/pageserver/src/tenant/storage_layer/delta_layer.rs b/pageserver/src/tenant/storage_layer/delta_layer.rs
index d9df346a14..a235034f76 100644
--- a/pageserver/src/tenant/storage_layer/delta_layer.rs
+++ b/pageserver/src/tenant/storage_layer/delta_layer.rs
@@ -45,8 +45,8 @@ use pageserver_api::models::{HistoricLayerInfo, LayerAccessKind};
 use rand::{distributions::Alphanumeric, Rng};
 use serde::{Deserialize, Serialize};
 use std::fs::{self, File};
+use std::io::SeekFrom;
 use std::io::{BufWriter, Write};
-use std::io::{Seek, SeekFrom};
 use std::ops::Range;
 use std::os::unix::fs::FileExt;
 use std::path::{Path, PathBuf};
diff --git a/pageserver/src/tenant/storage_layer/image_layer.rs b/pageserver/src/tenant/storage_layer/image_layer.rs
index b1fc257092..2d0d3a3dad 100644
--- a/pageserver/src/tenant/storage_layer/image_layer.rs
+++ b/pageserver/src/tenant/storage_layer/image_layer.rs
@@ -42,8 +42,8 @@ use pageserver_api::models::{HistoricLayerInfo, LayerAccessKind};
 use rand::{distributions::Alphanumeric, Rng};
 use serde::{Deserialize, Serialize};
 use std::fs::{self, File};
+use std::io::SeekFrom;
 use std::io::Write;
-use std::io::{Seek, SeekFrom};
 use std::ops::Range;
 use std::os::unix::prelude::FileExt;
 use std::path::{Path, PathBuf};
diff --git a/pageserver/src/virtual_file.rs b/pageserver/src/virtual_file.rs
index a86b8fa2a6..3d6c7f5cea 100644
--- a/pageserver/src/virtual_file.rs
+++ b/pageserver/src/virtual_file.rs
@@ -321,6 +321,31 @@ impl VirtualFile {
         drop(self);
         std::fs::remove_file(path).expect("failed to remove the virtual file");
     }
+
+    pub fn seek(&mut self, pos: SeekFrom) -> Result<u64, Error> {
+        match pos {
+            SeekFrom::Start(offset) => {
+                self.pos = offset;
+            }
+            SeekFrom::End(offset) => {
+                self.pos = self.with_file("seek", |mut file| file.seek(SeekFrom::End(offset)))??
+            }
+            SeekFrom::Current(offset) => {
+                let pos = self.pos as i128 + offset as i128;
+                if pos < 0 {
+                    return Err(Error::new(
+                        ErrorKind::InvalidInput,
+                        "offset would be negative",
+                    ));
+                }
+                if pos > u64::MAX as i128 {
+                    return Err(Error::new(ErrorKind::InvalidInput, "offset overflow"));
+                }
+                self.pos = pos as u64;
+            }
+        }
+        Ok(self.pos)
+    }
 }
 
 impl Drop for VirtualFile {
@@ -367,33 +392,6 @@ impl Write for VirtualFile {
     }
 }
 
-impl Seek for VirtualFile {
-    fn seek(&mut self, pos: SeekFrom) -> Result<u64, Error> {
-        match pos {
-            SeekFrom::Start(offset) => {
-                self.pos = offset;
-            }
-            SeekFrom::End(offset) => {
-                self.pos = self.with_file("seek", |mut file| file.seek(SeekFrom::End(offset)))??
-            }
-            SeekFrom::Current(offset) => {
-                let pos = self.pos as i128 + offset as i128;
-                if pos < 0 {
-                    return Err(Error::new(
-                        ErrorKind::InvalidInput,
-                        "offset would be negative",
-                    ));
-                }
-                if pos > u64::MAX as i128 {
-                    return Err(Error::new(ErrorKind::InvalidInput, "offset overflow"));
-                }
-                self.pos = pos as u64;
-            }
-        }
-        Ok(self.pos)
-    }
-}
-
 impl FileExt for VirtualFile {
     fn read_at(&self, buf: &mut [u8], offset: u64) -> Result<usize, Error> {
         let result = self.with_file("read", |file| file.read_at(buf, offset))?;