feat: ZipWriter set_auto_large_file() method to enable large-file data descriptor when necessary (#468)

* better write_data_descriptor #467

* useless

* Update src/types.rs

Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>
Signed-off-by: n4n5 <[email protected]>

* rm underscore

* cargo fmt

---------

Signed-off-by: n4n5 <[email protected]>
Co-authored-by: gemini-code-assist[bot] <176961590+gemini-code-assist[bot]@users.noreply.github.com>

Author: Its-Just-Nans

src/spec.rs

@@ -108,32 +108,32 @@ impl ExtraFieldMagic {
 ///
 /// let mut zip = ZipWriter::new(Cursor::new(Vec::new()));
 /// // Writing an extremely large file for this test is faster without compression.
-/// let options = SimpleFileOptions::default().compression_method(zip::CompressionMethod::Stored);
 ///
 /// let big_len: usize = (zip::ZIP64_BYTES_THR as usize) + 1;
 /// let big_buf = vec![0u8; big_len];
 /// {
-/// zip.start_file("zero.dat", options)?;
-/// // This is too big!
-/// let res = zip.write_all(&big_buf[..]).err().unwrap();
-/// assert_eq!(res.kind(), io::ErrorKind::Other);
-/// let description = format!("{}", &res);
-/// assert_eq!(description, "Large file option has not been set");
-/// }
-/// {
-/// // Attempting to write anything further to the same zip will still succeed, but the previous
-/// // failing entry has been removed.
-/// zip.start_file("one.dat", options)?;
-/// let zip = zip.finish_into_readable()?;
-/// let names: Vec<_> = zip.file_names().collect();
-/// assert_eq!(&names, &["one.dat"]);
+///     let options = SimpleFileOptions::default()
+///         .compression_method(zip::CompressionMethod::Stored);
+///     zip.start_file("zero.dat", options)?;
+///     // This is too big!
+///     let res = zip.write_all(&big_buf[..]).err().unwrap();
+///     assert_eq!(res.kind(), io::ErrorKind::Other);
+///     let description = format!("{}", &res);
+///     assert_eq!(description, "Large file option has not been set");
+///     // Attempting to write anything further to the same zip will still succeed, but the previous
+///     // failing entry has been removed.
+///     zip.start_file("one.dat", options)?;
+///     let zip = zip.finish_into_readable()?;
+///     let names: Vec<_> = zip.file_names().collect();
+///     assert_eq!(&names, &["one.dat"]);
 /// }
 ///
 /// // Create a new zip output.
 /// let mut zip = ZipWriter::new(Cursor::new(Vec::new()));
 /// // This time, create a zip64 record for the file.
 /// let options = SimpleFileOptions::default()
-///      .compression_method(zip::CompressionMethod::Stored).large_file(true);
+///      .compression_method(zip::CompressionMethod::Stored)
+///      .large_file(true);
 /// zip.start_file("zero.dat", options)?;
 /// // This succeeds because we specified that it could be a large file.
 /// assert!(zip.write_all(&big_buf[..]).is_ok());

src/types.rs

@@ -959,10 +959,21 @@ impl ZipFileData {
     pub(crate) fn write_data_descriptor<W: std::io::Write>(
         &self,
         writer: &mut W,
+        auto_large_file: bool,
     ) -> Result<(), ZipError> {
         if self.large_file {
             return self.zip64_data_descriptor_block().write(writer);
         }
+        if self.compressed_size > spec::ZIP64_BYTES_THR
+            || self.uncompressed_size > spec::ZIP64_BYTES_THR
+        {
+            if auto_large_file {
+                return self.zip64_data_descriptor_block().write(writer);
+            }
+            return Err(ZipError::Io(std::io::Error::other(
+                "Large file option has not been set - use .large_file(true) in options",
+            )));
+        }
         self.data_descriptor_block().write(writer)
     }
 

src/write.rs

@@ -172,6 +172,7 @@ pub(crate) mod zip_writer {
         pub(super) zip64_comment: Option<Box<[u8]>>,
         pub(super) flush_on_finish_file: bool,
         pub(super) seek_possible: bool,
+        pub(crate) auto_large_file: bool,
     }
 
     impl<W: Write + Seek> Debug for ZipWriter<W> {
@@ -650,6 +651,7 @@ impl<A: Read + Write + Seek> ZipWriter<A> {
             writing_raw: true, // avoid recomputing the last file's header
             flush_on_finish_file: false,
             seek_possible: true,
+            auto_large_file: false,
         })
     }
 
@@ -808,9 +810,16 @@ impl<W: Write + Seek> ZipWriter<W> {
             zip64_comment: None,
             flush_on_finish_file: false,
             seek_possible: true,
+            auto_large_file: false,
         }
     }
 
+    /// Set automatically large file to true if needed
+    pub fn set_auto_large_file(mut self) -> Self {
+        self.auto_large_file = true;
+        self
+    }
+
     /// Returns true if a file is currently open for writing.
     pub const fn is_writing_file(&self) -> bool {
         self.writing_to_file && !self.inner.is_closed()
@@ -1111,7 +1120,7 @@ impl<W: Write + Seek> ZipWriter<W> {
             };
             update_aes_extra_data(writer, file)?;
             if file.using_data_descriptor {
-                file.write_data_descriptor(writer)?;
+                file.write_data_descriptor(writer, self.auto_large_file)?;
             } else {
                 update_local_file_header(writer, file)?;
                 writer.seek(SeekFrom::Start(file_end))?;
@@ -1658,6 +1667,7 @@ impl<W: Write> ZipWriter<StreamWriter<W>> {
             zip64_comment: None,
             flush_on_finish_file: false,
             seek_possible: false,
+            auto_large_file: false,
         }
     }
 }