make the handling of pax extensions more general

Signed-off-by: Qinqi Qu <quqinqi@linux.alibaba.com>

src/archive.rs

@@ -275,7 +275,7 @@ impl<'a, R: Read> Iterator for Entries<'a, R> {
 impl<'a> EntriesFields<'a> {
  fn next_entry_raw(
  &mut self,
- pax_size: Option<u64>,
+ pax_extensions: &Option<Vec<u8>>,
  ) -> io::Result<Option<Entry<'a, io::Empty>>> {
  let mut header = Header::new_old();
  let mut header_pos = self.next;
@@ -315,6 +315,11 @@ impl<'a> EntriesFields<'a> {
  return Err(other("archive header checksum mismatch"));
  }
 
+ let mut pax_size: Option<u64> = None;
+ if let Some(pax_extensions_ref) = &pax_extensions {
+ pax_size = pax_extensions_value(pax_extensions_ref, "size");
+ }
+
  let file_pos = self.next;
  let mut size = header.entry_size()?;
  if size == 0 {
@@ -354,17 +359,16 @@ impl<'a> EntriesFields<'a> {
 
  fn next_entry(&mut self) -> io::Result<Option<Entry<'a, io::Empty>>> {
  if self.raw {
- return self.next_entry_raw(None);
+ return self.next_entry_raw(&None);
  }
 
  let mut gnu_longname = None;
  let mut gnu_longlink = None;
  let mut pax_extensions = None;
- let mut pax_size = None;
  let mut processed = 0;
  loop {
  processed += 1;
- let entry = match self.next_entry_raw(pax_size)? {
+ let entry = match self.next_entry_raw(&pax_extensions)? {
  Some(entry) => entry,
  None if processed > 1 => {
  return Err(other(
@@ -408,9 +412,6 @@ impl<'a> EntriesFields<'a> {
  ));
  }
  pax_extensions = Some(EntryFields::from(entry).read_all()?);
- if let Some(pax_extensions_ref) = &pax_extensions {
- pax_size = pax_extensions_value(pax_extensions_ref,"size");
- }
  continue;
  }