Replace file size check with a method that works with any file size o…

…pened with unbuffered I/O on Windows

crates/subspace-farmer-components/src/file_ext.rs

@@ -1,7 +1,7 @@
 //! File extension trait
 
 use std::fs::{File, OpenOptions};
-use std::io::{Result, Seek, SeekFrom};
+use std::io::Result;
 
 /// Extension convenience trait that allows setting some file opening options in cross-platform way
 pub trait OpenOptionsExt {
@@ -79,10 +79,10 @@ impl OpenOptionsExt for OpenOptions {
 /// and doing cross-platform exact reads/writes
 pub trait FileExt {
     /// Get file size
-    fn size(&mut self) -> Result<u64>;
+    fn size(&self) -> Result<u64>;
 
     /// Make sure file has specified number of bytes allocated for it
-    fn preallocate(&mut self, len: u64) -> Result<()>;
+    fn preallocate(&self, len: u64) -> Result<()>;
 
     /// Advise OS/file system that file will use random access and read-ahead behavior is
     /// undesirable, on Windows this can only be set when file is opened, see [`OpenOptionsExt`]
@@ -100,11 +100,11 @@ pub trait FileExt {
 }
 
 impl FileExt for File {
-    fn size(&mut self) -> Result<u64> {
-        self.seek(SeekFrom::End(0))
+    fn size(&self) -> Result<u64> {
+        Ok(self.metadata()?.len())
     }
 
-    fn preallocate(&mut self, len: u64) -> Result<()> {
+    fn preallocate(&self, len: u64) -> Result<()> {
         fs2::FileExt::allocate(self, len)
     }
 

crates/subspace-farmer/src/single_disk_farm.rs

@@ -1220,7 +1220,7 @@ impl SingleDiskFarm {
 
         let metadata_file_path = directory.join(Self::METADATA_FILE);
         #[cfg(not(windows))]
-        let mut metadata_file = OpenOptions::new()
+        let metadata_file = OpenOptions::new()
             .read(true)
             .write(true)
             .create(true)
@@ -1231,7 +1231,7 @@ impl SingleDiskFarm {
         metadata_file.advise_random_access()?;
 
         #[cfg(windows)]
-        let mut metadata_file = UnbufferedIoFileWindows::open(&metadata_file_path)?;
+        let metadata_file = UnbufferedIoFileWindows::open(&metadata_file_path)?;
 
         let metadata_size = metadata_file.size()?;
         let expected_metadata_size =
@@ -1323,7 +1323,7 @@ impl SingleDiskFarm {
         };
 
         #[cfg(not(windows))]
-        let mut plot_file = OpenOptions::new()
+        let plot_file = OpenOptions::new()
             .read(true)
             .write(true)
             .create(true)
@@ -1334,7 +1334,7 @@ impl SingleDiskFarm {
         plot_file.advise_random_access()?;
 
         #[cfg(windows)]
-        let mut plot_file = UnbufferedIoFileWindows::open(&directory.join(Self::PLOT_FILE))?;
+        let plot_file = UnbufferedIoFileWindows::open(&directory.join(Self::PLOT_FILE))?;
 
         if plot_file.size()? != plot_file_size {
             // Allocating the whole file (`set_len` below can create a sparse file, which will cause
@@ -1393,13 +1393,12 @@ impl SingleDiskFarm {
         directory: &Path,
     ) -> io::Result<Vec<SectorMetadataChecksummed>> {
         #[cfg(not(windows))]
-        let mut metadata_file = OpenOptions::new()
+        let metadata_file = OpenOptions::new()
             .read(true)
             .open(directory.join(Self::METADATA_FILE))?;
 
         #[cfg(windows)]
-        let mut metadata_file =
-            UnbufferedIoFileWindows::open(&directory.join(Self::METADATA_FILE))?;
+        let metadata_file = UnbufferedIoFileWindows::open(&directory.join(Self::METADATA_FILE))?;
 
         let metadata_size = metadata_file.size()?;
         let sector_metadata_size = SectorMetadataChecksummed::encoded_size();
@@ -1665,7 +1664,7 @@ impl SingleDiskFarm {
         let (metadata_file, mut metadata_header) = {
             info!(path = %metadata_file_path.display(), "Checking metadata file");
 
-            let mut metadata_file = match OpenOptions::new()
+            let metadata_file = match OpenOptions::new()
                 .read(true)
                 .write(true)
                 .open(&metadata_file_path)
@@ -1766,7 +1765,7 @@ impl SingleDiskFarm {
             let plot_file_path = directory.join(Self::PLOT_FILE);
             info!(path = %plot_file_path.display(), "Checking plot file");
 
-            let mut plot_file = match OpenOptions::new()
+            let plot_file = match OpenOptions::new()
                 .read(true)
                 .write(true)
                 .open(&plot_file_path)
@@ -2042,7 +2041,7 @@ impl SingleDiskFarm {
             let file = directory.join(DiskPieceCache::FILE_NAME);
             info!(path = %file.display(), "Checking cache file");
 
-            let mut cache_file = match OpenOptions::new().read(true).write(true).open(&file) {
+            let cache_file = match OpenOptions::new().read(true).write(true).open(&file) {
                 Ok(plot_file) => plot_file,
                 Err(error) => {
                     return Err(if error.kind() == io::ErrorKind::NotFound {

crates/subspace-farmer/src/single_disk_farm/piece_cache.rs

@@ -73,7 +73,7 @@ impl DiskPieceCache {
         }
 
         #[cfg(not(windows))]
-        let mut file = OpenOptions::new()
+        let file = OpenOptions::new()
             .read(true)
             .write(true)
             .create(true)
@@ -84,7 +84,7 @@ impl DiskPieceCache {
         file.advise_random_access()?;
 
         #[cfg(windows)]
-        let mut file = UnbufferedIoFileWindows::open(&directory.join(Self::FILE_NAME))?;
+        let file = UnbufferedIoFileWindows::open(&directory.join(Self::FILE_NAME))?;
 
         let expected_size = u64::from(Self::element_size()) * u64::from(capacity);
         // Align plot file size for disk sector size

crates/subspace-farmer/src/single_disk_farm/plot_cache/tests.rs

@@ -31,7 +31,7 @@ fn basic() {
 
     let tempdir = tempdir().unwrap();
     #[cfg(not(windows))]
-    let mut file = OpenOptions::new()
+    let file = OpenOptions::new()
         .read(true)
         .write(true)
         .create(true)
@@ -40,7 +40,7 @@ fn basic() {
         .unwrap();
 
     #[cfg(windows)]
-    let mut file = UnbufferedIoFileWindows::open(&tempdir.path().join("plot.bin")).unwrap();
+    let file = UnbufferedIoFileWindows::open(&tempdir.path().join("plot.bin")).unwrap();
 
     // Align plot file size for disk sector size
     file.preallocate(

crates/subspace-farmer/src/single_disk_farm/unbuffered_io_file_windows.rs

@@ -2,7 +2,6 @@ use parking_lot::Mutex;
 use static_assertions::const_assert_eq;
 use std::fs::{File, OpenOptions};
 use std::io;
-use std::io::{Seek, SeekFrom};
 use std::path::Path;
 use subspace_farmer_components::file_ext::FileExt;
 #[cfg(windows)]
@@ -38,11 +37,11 @@ impl ReadAtSync for &UnbufferedIoFileWindows {
 }
 
 impl FileExt for UnbufferedIoFileWindows {
-    fn size(&mut self) -> io::Result<u64> {
-        self.file.seek(SeekFrom::End(0))
+    fn size(&self) -> io::Result<u64> {
+        Ok(self.file.metadata()?.len())
     }
 
-    fn preallocate(&mut self, len: u64) -> io::Result<()> {
+    fn preallocate(&self, len: u64) -> io::Result<()> {
         self.file.preallocate(len)
     }