fix(storage): use u8 for NippiJar's DataReader::offset_size (#8360)

crates/storage/nippy-jar/src/error.rs

@@ -40,7 +40,7 @@ pub enum NippyJarError {
     #[error("the size of an offset must be at most 8 bytes, got {offset_size}")]
     OffsetSizeTooBig {
         /// The read offset size in number of bytes.
-        offset_size: u64,
+        offset_size: u8,
     },
     #[error("attempted to read an out of bounds offset: {index}")]
     OffsetOutOfBounds {

crates/storage/nippy-jar/src/lib.rs

@@ -476,7 +476,7 @@ pub struct DataReader {
     /// Mmap handle for offsets.
     offset_mmap: Mmap,
     /// Number of bytes that represent one offset.
-    offset_size: u64,
+    offset_size: u8,
 }
 
 impl DataReader {
@@ -491,7 +491,7 @@ impl DataReader {
         let offset_mmap = unsafe { Mmap::map(&offset_file)? };
 
         // First byte is the size of one offset in bytes
-        let offset_size = offset_mmap[0] as u64;
+        let offset_size = offset_mmap[0];
 
         // Ensure that the size of an offset is at most 8 bytes.
         if offset_size > 8 {
@@ -525,7 +525,8 @@ impl DataReader {
     /// Returns total number of offsets in the file.
     /// The size of one offset is determined by the file itself.
     pub fn offsets_count(&self) -> Result<usize, NippyJarError> {
-        Ok((self.offset_file.metadata()?.len().saturating_sub(1) / self.offset_size) as usize)
+        Ok((self.offset_file.metadata()?.len().saturating_sub(1) / self.offset_size as u64)
+            as usize)
     }
 
     /// Reads one offset-sized (determined by the offset file) u64 at the provided index.
@@ -542,7 +543,7 @@ impl DataReader {
     }
 
     /// Returns number of bytes that represent one offset.
-    pub fn offset_size(&self) -> u64 {
+    pub fn offset_size(&self) -> u8 {
         self.offset_size
     }
 

crates/storage/nippy-jar/src/writer.rs

@@ -7,7 +7,7 @@ use std::{
 };
 
 /// Size of one offset in bytes.
-const OFFSET_SIZE_BYTES: u64 = 8;
+const OFFSET_SIZE_BYTES: u8 = 8;
 
 /// Writer of [`NippyJar`]. Handles table data and offsets only.
 ///
@@ -112,7 +112,7 @@ impl<H: NippyJarHeader> NippyJarWriter<H> {
         let mut offsets_file = OpenOptions::new().read(true).write(true).open(offsets)?;
 
         // First byte of the offset file is the size of one offset in bytes
-        offsets_file.write_all(&[OFFSET_SIZE_BYTES as u8])?;
+        offsets_file.write_all(&[OFFSET_SIZE_BYTES])?;
         offsets_file.seek(SeekFrom::End(0))?;
 
         Ok((data_file, offsets_file, is_created))
@@ -133,9 +133,9 @@ impl<H: NippyJarHeader> NippyJarWriter<H> {
             return Err(NippyJarError::FrozenJar)
         }
 
-        let expected_offsets_file_size = 1 + // first byte is the size of one offset
-            OFFSET_SIZE_BYTES * self.jar.rows as u64 * self.jar.columns as u64 + // `offset size * num rows * num columns`
-            OFFSET_SIZE_BYTES; // expected size of the data file
+        let expected_offsets_file_size: u64 = (1 + // first byte is the size of one offset
+            OFFSET_SIZE_BYTES as usize* self.jar.rows * self.jar.columns + // `offset size * num rows * num columns`
+            OFFSET_SIZE_BYTES as usize) as u64; // expected size of the data file
         let actual_offsets_file_size = self.offsets_file.get_ref().metadata()?.len();
 
         // Offsets configuration wasn't properly committed
@@ -151,9 +151,9 @@ impl<H: NippyJarHeader> NippyJarWriter<H> {
                 // `num rows = (file size - 1 - size of one offset) / num columns`
                 self.jar.rows = ((actual_offsets_file_size.
                     saturating_sub(1). // first byte is the size of one offset
-                    saturating_sub(OFFSET_SIZE_BYTES) / // expected size of the data file
+                    saturating_sub(OFFSET_SIZE_BYTES as u64) / // expected size of the data file
                     (self.jar.columns as u64)) /
-                    OFFSET_SIZE_BYTES) as usize;
+                    OFFSET_SIZE_BYTES as u64) as usize;
 
                 // Freeze row count changed
                 self.jar.freeze_config()?;
@@ -183,7 +183,7 @@ impl<H: NippyJarHeader> NippyJarWriter<H> {
                             .get_ref()
                             .metadata()?
                             .len()
-                            .saturating_sub(OFFSET_SIZE_BYTES * (index as u64 + 1));
+                            .saturating_sub(OFFSET_SIZE_BYTES as u64 * (index as u64 + 1));
                         self.offsets_file.get_mut().set_len(new_len)?;
 
                         drop(reader);
@@ -318,7 +318,7 @@ impl<H: NippyJarHeader> NippyJarWriter<H> {
             // Handle non-empty offset file
             if length > 1 {
                 // first byte is reserved for `bytes_per_offset`, which is 8 initially.
-                let num_offsets = (length - 1) / OFFSET_SIZE_BYTES;
+                let num_offsets = (length - 1) / OFFSET_SIZE_BYTES as u64;
 
                 if remaining_to_prune as u64 > num_offsets {
                     return Err(NippyJarError::InvalidPruning(
@@ -336,10 +336,10 @@ impl<H: NippyJarHeader> NippyJarWriter<H> {
                     self.data_file.get_mut().set_len(0)?;
                 } else {
                     // Calculate the new length for the on-disk offset list
-                    let new_len = 1 + new_num_offsets * OFFSET_SIZE_BYTES;
+                    let new_len = 1 + new_num_offsets * OFFSET_SIZE_BYTES as u64;
                     // Seek to the position of the last offset
                     self.offsets_file
-                        .seek(SeekFrom::Start(new_len.saturating_sub(OFFSET_SIZE_BYTES)))?;
+                        .seek(SeekFrom::Start(new_len.saturating_sub(OFFSET_SIZE_BYTES as u64)))?;
                     // Read the last offset value
                     let mut last_offset = [0u8; OFFSET_SIZE_BYTES as usize];
                     self.offsets_file.get_ref().read_exact(&mut last_offset)?;