Wrap extra data in Rc so FileOptions and ZipFileData can be cloned faster

src/read.rs

@@ -14,6 +14,7 @@ use std::borrow::Cow;
 use std::collections::HashMap;
 use std::io::{self, prelude::*};
 use std::path::Path;
+use std::rc::Rc;
 use std::sync::Arc;
 
 #[cfg(any(
@@ -358,13 +359,13 @@ impl<R: Read + Seek> ZipArchive<R> {
         }
         if footer64.number_of_files_on_this_disk > footer64.number_of_files {
             return Err(ZipError::InvalidArchive(
-                "ZIP64 footer indicates more files on this disk than in the whole archive"
+                "ZIP64 footer indicates more files on this disk than in the whole archive",
             ));
         }
         if footer64.version_needed_to_extract > footer64.version_made_by {
             return Err(ZipError::InvalidArchive(
                 "ZIP64 footer indicates a new version is needed to extract this archive than the \
-                version that wrote it"
+                version that wrote it",
             ));
         }
 
@@ -737,8 +738,8 @@ fn central_header_to_zip_file_inner<R: Read>(
         uncompressed_size: uncompressed_size as u64,
         file_name,
         file_name_raw,
-        extra_field,
+        extra_field: Rc::new(extra_field),
-        central_extra_field: vec![],
+        central_extra_field: Rc::new(vec![]),
         file_comment,
         header_start: offset,
         central_header_start,
@@ -770,7 +771,7 @@ fn central_header_to_zip_file_inner<R: Read>(
 }
 
 fn parse_extra_field(file: &mut ZipFileData) -> ZipResult<()> {
-    let mut reader = io::Cursor::new(&file.extra_field);
+    let mut reader = io::Cursor::new(file.extra_field.as_ref());
 
     while (reader.position() as usize) < file.extra_field.len() {
         let kind = reader.read_u16::<LittleEndian>()?;
@@ -1098,8 +1099,8 @@ pub fn read_zipfile_from_stream<'a, R: Read>(reader: &'a mut R) -> ZipResult<Opt
         uncompressed_size: uncompressed_size as u64,
         file_name,
         file_name_raw,
-        extra_field,
+        extra_field: Rc::new(extra_field),
-        central_extra_field: vec![],
+        central_extra_field: Rc::new(vec![]),
         file_comment: String::new(), // file comment is only available in the central directory
         // header_start and data start are not available, but also don't matter, since seeking is
         // not available.

src/types.rs

@@ -1,6 +1,7 @@
 //! Types that specify what is contained in a ZIP.
 use path::{Component, Path, PathBuf};
 use std::path;
+use std::rc::Rc;
 
 #[cfg(not(any(
     all(target_arch = "arm", target_pointer_width = "32"),
@@ -361,9 +362,9 @@ pub struct ZipFileData {
     /// Raw file name. To be used when file_name was incorrectly decoded.
     pub file_name_raw: Vec<u8>,
     /// Extra field usually used for storage expansion
-    pub extra_field: Vec<u8>,
+    pub extra_field: Rc<Vec<u8>>,
     /// Extra field only written to central directory
-    pub central_extra_field: Vec<u8>,
+    pub central_extra_field: Rc<Vec<u8>>,
     /// File comment
     pub file_comment: String,
     /// Specifies where the local header of the file starts
@@ -530,8 +531,8 @@ mod test {
             uncompressed_size: 0,
             file_name: file_name.clone(),
             file_name_raw: file_name.into_bytes(),
-            extra_field: Vec::new(),
+            extra_field: Rc::new(vec![]),
-            central_extra_field: vec![],
+            central_extra_field: Rc::new(vec![]),
             file_comment: String::new(),
             header_start: 0,
             data_start: AtomicU64::new(0),

src/write.rs

@@ -14,6 +14,7 @@ use std::io;
 use std::io::prelude::*;
 use std::io::{BufReader, SeekFrom};
 use std::mem;
+use std::rc::Rc;
 
 #[cfg(any(
     feature = "deflate",
@@ -133,8 +134,8 @@ pub struct FileOptions {
     pub(crate) permissions: Option<u32>,
     pub(crate) large_file: bool,
     encrypt_with: Option<ZipCryptoKeys>,
-    extra_data: Vec<u8>,
+    extra_data: Rc<Vec<u8>>,
-    central_extra_data: Vec<u8>,
+    central_extra_data: Rc<Vec<u8>>,
     alignment: u16,
 }
 
@@ -251,9 +252,17 @@ impl FileOptions {
             } else {
                 &mut self.extra_data
             };
-            field.write_u16::<LittleEndian>(header_id)?;
+            let vec = Rc::get_mut(field);
-            field.write_u16::<LittleEndian>(data.len() as u16)?;
+            let vec = match vec {
-            field.write_all(data)?;
+                Some(exclusive) => exclusive,
+                None => {
+                    *field = Rc::new(field.to_vec());
+                    Rc::get_mut(field).unwrap()
+                }
+            };
+            vec.write_u16::<LittleEndian>(header_id)?;
+            vec.write_u16::<LittleEndian>(data.len() as u16)?;
+            vec.write_all(data)?;
             Ok(())
         }
     }
@@ -261,8 +270,12 @@ impl FileOptions {
     /// Removes the extra data fields.
     #[must_use]
     pub fn clear_extra_data(mut self) -> FileOptions {
-        self.extra_data.clear();
+        if self.extra_data.len() > 0 {
-        self.central_extra_data.clear();
+            self.extra_data = Rc::new(vec![]);
+        }
+        if self.central_extra_data.len() > 0 {
+            self.central_extra_data = Rc::new(vec![]);
+        }
         self
     }
 }
@@ -291,8 +304,8 @@ impl Default for FileOptions {
             permissions: None,
             large_file: false,
             encrypt_with: None,
-            extra_data: Vec::with_capacity(u16::MAX as usize),
+            extra_data: Rc::new(vec![]),
-            central_extra_data: Vec::with_capacity(u16::MAX as usize),
+            central_extra_data: Rc::new(vec![]),
             alignment: 1,
         }
     }
@@ -1384,6 +1397,7 @@ mod test {
     use crate::ZipArchive;
     use std::io;
     use std::io::{Read, Write};
+    use std::rc::Rc;
 
     #[test]
     fn write_empty_zip() {
@@ -1503,8 +1517,8 @@ mod test {
             permissions: Some(33188),
             large_file: false,
             encrypt_with: None,
-            extra_data: vec![],
+            extra_data: Rc::new(vec![]),
-            central_extra_data: vec![],
+            central_extra_data: Rc::new(vec![]),
             alignment: 1,
         };
         writer.start_file("mimetype", options).unwrap();
@@ -1543,8 +1557,8 @@ mod test {
             permissions: Some(33188),
             large_file: false,
             encrypt_with: None,
-            extra_data: vec![],
+            extra_data: Rc::new(vec![]),
-            central_extra_data: vec![],
+            central_extra_data: Rc::new(vec![]),
             alignment: 0,
         };
         writer.start_file(RT_TEST_FILENAME, options).unwrap();
@@ -1593,8 +1607,8 @@ mod test {
             permissions: Some(33188),
             large_file: false,
             encrypt_with: None,
-            extra_data: vec![],
+            extra_data: Rc::new(vec![]),
-            central_extra_data: vec![],
+            central_extra_data: Rc::new(vec![]),
             alignment: 0,
         };
         writer.start_file(RT_TEST_FILENAME, options).unwrap();
@@ -1705,12 +1719,21 @@ mod test {
     #[test]
     fn test_filename_looks_like_zip64_locator_4() {
         let mut writer = ZipWriter::new(io::Cursor::new(Vec::new()));
-        writer.start_file("PK\u{6}\u{6}", FileOptions::default()).unwrap();
+        writer
-        writer.start_file("\0\0\0\0\0\0", FileOptions::default()).unwrap();
+            .start_file("PK\u{6}\u{6}", FileOptions::default())
+            .unwrap();
+        writer
+            .start_file("\0\0\0\0\0\0", FileOptions::default())
+            .unwrap();
         writer.start_file("\0", FileOptions::default()).unwrap();
         writer.start_file("", FileOptions::default()).unwrap();
         writer.start_file("\0\0", FileOptions::default()).unwrap();
-        writer.start_file("\0\0\0PK\u{6}\u{7}\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0", FileOptions::default()).unwrap();
+        writer
+            .start_file(
+                "\0\0\0PK\u{6}\u{7}\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0",
+                FileOptions::default(),
+            )
+            .unwrap();
         let zip = writer.finish().unwrap();
         println!("{:02x?}", zip.get_ref());
         let _ = ZipArchive::new(zip).unwrap();