Add raw entries interface to ledger for getting slices as [u8]
This commit is contained in:
parent
ae150c0897
commit
183f560d06
125
src/ledger.rs
125
src/ledger.rs
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@ -82,18 +82,19 @@ fn err_bincode_to_io(e: Box<bincode::ErrorKind>) -> io::Error {
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io::Error::new(io::ErrorKind::Other, e.to_string())
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}
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fn entry_at<A: Read + Seek>(file: &mut A, at: u64) -> io::Result<Entry> {
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file.seek(SeekFrom::Start(at))?;
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let len = deserialize_from(file.take(SIZEOF_U64)).map_err(err_bincode_to_io)?;
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trace!("entry_at({}) len: {}", at, len);
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fn read_entry<A: Read>(file: &mut A, len: u64) -> io::Result<Entry> {
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deserialize_from(file.take(len)).map_err(err_bincode_to_io)
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}
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fn entry_at<A: Read + Seek>(file: &mut A, at: u64) -> io::Result<Entry> {
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let len = u64_at(file, at)?;
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read_entry(file, len)
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}
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fn next_entry<A: Read>(file: &mut A) -> io::Result<Entry> {
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let len = deserialize_from(file.take(SIZEOF_U64)).map_err(err_bincode_to_io)?;
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deserialize_from(file.take(len)).map_err(err_bincode_to_io)
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read_entry(file, len)
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}
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fn u64_at<A: Read + Seek>(file: &mut A, at: u64) -> io::Result<u64> {
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@ -116,9 +117,55 @@ impl LedgerWindow {
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}
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pub fn get_entry(&mut self, index: u64) -> io::Result<Entry> {
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let offset = u64_at(&mut self.index, index * SIZEOF_U64)?;
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let offset = self.get_entry_offset(index)?;
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entry_at(&mut self.data, offset)
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}
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// Fill 'buf' with num_entries or most number of whole entries that fit into buf.len()
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//
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// Return tuple of (number of entries read, total size of entries read)
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pub fn get_entries_bytes(
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&mut self,
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start_index: u64,
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num_entries: u64,
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buf: &mut [u8],
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) -> io::Result<(u64, u64)> {
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let start_offset = self.get_entry_offset(start_index)?;
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let mut total_entries = 0;
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let mut end_offset = 0;
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for i in 0..num_entries {
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let offset = self.get_entry_offset(start_index + i)?;
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let len = u64_at(&mut self.data, offset)?;
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let cur_end_offset = offset + len + SIZEOF_U64;
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if (cur_end_offset - start_offset) > buf.len() as u64 {
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break;
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}
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end_offset = cur_end_offset;
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total_entries += 1;
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}
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if total_entries == 0 {
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return Ok((0, 0));
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}
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let read_len = end_offset - start_offset;
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self.data.seek(SeekFrom::Start(start_offset))?;
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let fread_len = self.data.read(&mut buf[..read_len as usize])? as u64;
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if fread_len != read_len {
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return Err(io::Error::new(
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io::ErrorKind::Other,
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format!(
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"entry read_len({}) doesn't match expected ({})",
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fread_len, read_len
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),
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));
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}
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Ok((total_entries, read_len))
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}
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fn get_entry_offset(&mut self, index: u64) -> io::Result<u64> {
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u64_at(&mut self.index, index * SIZEOF_U64)
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}
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}
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pub fn verify_ledger(ledger_path: &str) -> io::Result<()> {
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@ -874,4 +921,66 @@ mod tests {
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let _ignored = remove_dir_all(&ledger_path);
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}
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#[test]
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fn test_get_entries_bytes() {
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use logger;
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logger::setup();
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let entries = make_tiny_test_entries(10);
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let ledger_path = tmp_ledger_path("test_raw_entries");
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{
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let mut writer = LedgerWriter::open(&ledger_path, true).unwrap();
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writer.write_entries(entries.clone()).unwrap();
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}
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let mut window = LedgerWindow::open(&ledger_path).unwrap();
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let mut buf = [0; 1024];
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let (num_entries, bytes) = window.get_entries_bytes(0, 1, &mut buf).unwrap();
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let bytes = bytes as usize;
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assert_eq!(num_entries, 1);
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let entry: Entry = deserialize(&buf[size_of::<u64>()..bytes]).unwrap();
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assert_eq!(entry, entries[0]);
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let (num_entries, bytes2) = window.get_entries_bytes(0, 2, &mut buf).unwrap();
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let bytes2 = bytes2 as usize;
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assert_eq!(num_entries, 2);
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assert!(bytes2 > bytes);
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for (i, ref entry) in entries.iter().enumerate() {
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info!("entry[{}] = {:?}", i, entry.id);
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}
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let entry: Entry = deserialize(&buf[size_of::<u64>()..bytes]).unwrap();
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assert_eq!(entry, entries[0]);
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let entry: Entry = deserialize(&buf[bytes + size_of::<u64>()..bytes2]).unwrap();
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assert_eq!(entry, entries[1]);
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// buf size part-way into entry[1], should just return entry[0]
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let mut buf = vec![0; bytes + size_of::<u64>() + 1];
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let (num_entries, bytes3) = window.get_entries_bytes(0, 2, &mut buf).unwrap();
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assert_eq!(num_entries, 1);
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let bytes3 = bytes3 as usize;
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assert_eq!(bytes3, bytes);
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let mut buf = vec![0; bytes2 - 1];
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let (num_entries, bytes4) = window.get_entries_bytes(0, 2, &mut buf).unwrap();
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assert_eq!(num_entries, 1);
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let bytes4 = bytes4 as usize;
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assert_eq!(bytes4, bytes);
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let mut buf = vec![0; bytes + size_of::<u64>() - 1];
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let (num_entries, bytes5) = window.get_entries_bytes(0, 2, &mut buf).unwrap();
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assert_eq!(num_entries, 1);
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let bytes5 = bytes5 as usize;
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assert_eq!(bytes5, bytes);
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let mut buf = vec![0; bytes * 2];
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let (num_entries, bytes6) = window.get_entries_bytes(9, 1, &mut buf).unwrap();
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assert_eq!(num_entries, 1);
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let bytes6 = bytes6 as usize;
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assert_eq!(bytes6, bytes);
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// Read out of range
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assert!(window.get_entries_bytes(20, 2, &mut buf).is_err());
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}
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}
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