an efficient binary archive format
re-use vacuum file
+39
-50
+39
-50
src/bindle.rs
+39
-50
src/bindle.rs
···
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pub fn vacuum(&mut self) -> io::Result<()> {
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let temp_path = self.path.with_extension("tmp");
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// Create and lock temp file
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let result = {
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let mut temp_file = OpenOptions::new()
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.write(true)
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.read(true)
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.create(true)
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.truncate(true)
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.open(&temp_path)?;
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// Create temp file and keep handle to reuse after rename
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let mut temp_file = OpenOptions::new()
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.write(true)
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.read(true)
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.create(true)
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.truncate(true)
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.open(&temp_path)?;
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temp_file.lock_exclusive()?;
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temp_file.write_all(BNDL_MAGIC)?;
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let mut current_offset = HEADER_SIZE as u64;
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temp_file.lock_exclusive()?;
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temp_file.write_all(BNDL_MAGIC)?;
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let mut current_offset = HEADER_SIZE as u64;
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// Copy only live entries from original to temp
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for entry in self.index.values_mut() {
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let mut buf = vec![0u8; entry.compressed_size() as usize];
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self.file.seek(SeekFrom::Start(entry.offset()))?;
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self.file.read_exact(&mut buf)?;
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// Copy only live entries from original to temp
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for entry in self.index.values_mut() {
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let mut buf = vec![0u8; entry.compressed_size() as usize];
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self.file.seek(SeekFrom::Start(entry.offset()))?;
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self.file.read_exact(&mut buf)?;
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temp_file.seek(SeekFrom::Start(current_offset))?;
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temp_file.write_all(&buf)?;
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temp_file.seek(SeekFrom::Start(current_offset))?;
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temp_file.write_all(&buf)?;
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entry.set_offset(current_offset);
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let pad = pad::<8, u64>(entry.compressed_size());
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if pad > 0 {
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write_padding(&mut temp_file, pad as usize)?;
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}
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current_offset += entry.compressed_size() + pad;
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entry.set_offset(current_offset);
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let pad = pad::<8, u64>(entry.compressed_size());
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if pad > 0 {
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write_padding(&mut temp_file, pad as usize)?;
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}
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current_offset += entry.compressed_size() + pad;
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}
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// Write the index and footer
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let index_start = current_offset;
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for (name, entry) in &self.index {
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temp_file.write_all(entry.as_bytes())?;
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temp_file.write_all(name.as_bytes())?;
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let pad = pad::<BNDL_ALIGN, usize>(ENTRY_SIZE + name.len());
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if pad > 0 {
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write_padding(&mut temp_file, pad)?;
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}
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// Write the index and footer
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let index_start = current_offset;
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for (name, entry) in &self.index {
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temp_file.write_all(entry.as_bytes())?;
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temp_file.write_all(name.as_bytes())?;
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let pad = pad::<BNDL_ALIGN, usize>(ENTRY_SIZE + name.len());
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if pad > 0 {
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write_padding(&mut temp_file, pad)?;
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}
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let footer = Footer::new(index_start, self.index.len() as u32, FOOTER_MAGIC);
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temp_file.write_all(footer.as_bytes())?;
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temp_file.sync_all()?;
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Ok(())
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};
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// Handle result
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if let Err(e) = result {
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std::fs::remove_file(&temp_path).ok();
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return Err(e);
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}
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let footer = Footer::new(index_start, self.index.len() as u32, FOOTER_MAGIC);
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temp_file.write_all(footer.as_bytes())?;
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temp_file.sync_all()?;
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// Acquire exclusive lock just before rename to prevent concurrent access
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self.file.lock_exclusive()?;
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···
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// Atomically replace original with temp
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std::fs::rename(&temp_path, &self.path)?;
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// Re-open the new file
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let file = OpenOptions::new().read(true).write(true).open(&self.path)?;
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file.lock_shared()?;
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let mmap = unsafe { Mmap::map(&file)? };
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// Reuse temp_file handle (still valid after rename)
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temp_file.lock_shared()?;
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let mmap = unsafe { Mmap::map(&temp_file)? };
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let footer_pos = mmap.len() - FOOTER_SIZE;
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let footer = Footer::read_from_bytes(&mmap[footer_pos..]).map_err(|_| {
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io::Error::new(io::ErrorKind::InvalidData, "Failed to read footer after vacuum")
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})?;
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self.file = file;
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self.file = temp_file;
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self.mmap = Some(mmap);
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self.data_end = footer.index_offset();
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