zip 9.0.4

//! Code related to zipfile

use crate::CompressionMethod;
use crate::DateTime;
use crate::HasZipMetadata;
use crate::ZIP64_BYTES_THR;
use crate::ZipReadOptions;
use crate::format::data_descriptor::ZipDataDescriptor;
use crate::format::ffi;
use crate::format::flags::ZipFileFlags;
use crate::format::system::System;
use crate::read::ExtraField;
use crate::read::extract::RootDirFilter;
use crate::read::readers::{ZipFileReader, ZipFileSeekReader};
use crate::result::ZipResult;
use crate::result::invalid;
use crate::types::ZipFileData;
use crate::write::options::SimpleFileOptions;

use core::mem::replace;
use std::borrow::Cow;
use std::ffi::OsStr;
use std::io::{self, Cursor, Read, Seek, SeekFrom, copy, sink};
use std::path::{Path, PathBuf};

/// A struct for reading a zip file
///
/// When reading from a `ZipFile` using [`Self::read()`], keep in mind that `read()` **does not guarantee** the buffer will be fully filled in a single call.
///
/// If your logic depends on the buffer being completely populated, use [`Self::read_exact()`] instead. It will continue reading until the entire buffer is filled or an error occurs.
#[derive(Debug)]
pub struct ZipFile<'a, R: Read + ?Sized> {
    pub(crate) file_name_raw: Cow<'a, [u8]>,
    pub(crate) data: Cow<'a, ZipFileData>,
    pub(crate) reader: ZipFileReader<'a, R>,
}

/// A zip file Entry with a data descriptor (if present).
///
/// The method [`Self::data_descriptor`] can be use to retrieve it
#[derive(Debug)]
pub struct ZipFileEntryWithDataDescriptor<'a> {
    pub(crate) file_name_raw: Cow<'a, [u8]>,
    pub(crate) data: Cow<'a, ZipFileData>,
    pub(crate) data_descriptor: Option<ZipDataDescriptor>,
}

/// A struct for reading a zip file, without a reader
#[derive(Debug)]
pub struct ZipFileEntry<'a> {
    pub(crate) file_name_raw: Cow<'a, [u8]>,
    pub(crate) data: Cow<'a, ZipFileData>,
}

/// A struct for reading and seeking a zip file
pub struct ZipFileSeek<'a, R> {
    pub(crate) file_name_raw: Cow<'a, [u8]>,
    pub(crate) data: Cow<'a, ZipFileData>,
    pub(crate) reader: ZipFileSeekReader<'a, R>,
}

macro_rules! zip_file_methods {
    () => {
        /// Get the name of the file, in the raw (internal) byte representation.
        ///
        /// The encoding of this data is currently undefined.
        pub fn name_raw(&self) -> &[u8] {
            &self.file_name_raw
        }

        /// Get the name of the file
        ///
        /// # Warnings
        ///
        /// It is dangerous to use this name directly when extracting an archive.
        /// It may contain an absolute path (`/etc/shadow`), or break out of the
        /// current directory (`../runtime`). Carelessly writing to these paths
        /// allows an attacker to craft a ZIP archive that will overwrite critical
        /// files.
        ///
        /// You can use the [`ZipFile::enclosed_name`] method to validate the name
        /// as a safe path.
        pub fn name(&self) -> ZipResult<Cow<'_, str>> {
            self.get_metadata().name(&self.file_name_raw)
        }

        /// Rewrite the path, ignoring any path components with special meaning.
        ///
        /// - Absolute paths are made relative
        /// - [`ParentDir`]s are ignored
        /// - Truncates the filename at a NULL byte
        ///
        /// This is appropriate if you need to be able to extract *something* from
        /// any archive, but will easily misrepresent trivial paths like
        /// `foo/../bar` as `foo/bar` (instead of `bar`). Because of this,
        /// [`ZipFile::enclosed_name`] is the better option in most scenarios.
        ///
        /// [`ParentDir`]: `std::path::Component::ParentDir`
        pub fn mangled_name(&self) -> ZipResult<PathBuf> {
            let file_name = self.name()?;
            let sanitized = self.get_metadata().file_name_sanitized(&file_name);
            Ok(sanitized)
        }

        /// Ensure the file path is safe to use as a [`Path`].
        ///
        /// - It can't contain NULL bytes
        /// - It can't resolve to a path outside the current directory
        ///   > `foo/../bar` is fine, `foo/../../bar` is not.
        /// - It can't be an absolute path
        ///
        /// This will read well-formed ZIP files correctly, and is resistant
        /// to path-based exploits. It is recommended over
        /// [`ZipFile::mangled_name`].
        pub fn enclosed_name(&self) -> Option<PathBuf> {
            self.get_metadata().enclosed_name(&self.name().ok()?)
        }

        /// Get the starting offset of the zip header for this file
        pub fn header_start(&self) -> u64 {
            self.get_metadata().header_start
        }
        /// Get the starting offset of the zip header in the central directory for this file
        pub fn central_header_start(&self) -> u64 {
            self.get_metadata().central_header_start
        }

        /// Get the version of the file
        pub fn version_made_by(&self) -> (u8, u8) {
            (
                self.get_metadata().version_made_by / 10,
                self.get_metadata().version_made_by % 10,
            )
        }

        /// PKZIP version needed to open this file (from APPNOTE 4.4.3.2).
        pub fn version_needed(&self) -> u16 {
            self.get_metadata().version_needed()
        }

        /// Get the comment of the file
        pub fn comment(&self) -> &str {
            &self.get_metadata().file_comment
        }

        /// Get the system of the file
        pub fn system(&self) -> System {
            self.get_metadata().system
        }

        /// Get the external attributes of the file
        pub fn external_attributes(&self) -> u32 {
            self.get_metadata().external_attributes
        }

        /// Get the flags of the file
        pub fn flags(&self) -> ZipFileFlags {
            self.get_metadata().flags
        }

        /// Get the compression method used to store the file
        pub fn compression(&self) -> CompressionMethod {
            self.get_metadata().compression_method
        }

        /// Get if the files is encrypted or not
        pub fn encrypted(&self) -> bool {
            self.data.is_encrypted()
        }

        /// Get the size of the file, in bytes, in the archive
        pub fn compressed_size(&self) -> u64 {
            self.get_metadata().compressed_size
        }

        /// Get the size of the file, in bytes, when uncompressed
        pub fn size(&self) -> u64 {
            self.get_metadata().uncompressed_size
        }

        /// Get the time the file was last modified
        pub fn last_modified(&self) -> Option<DateTime> {
            self.get_metadata().last_modified_time
        }
        /// Returns whether the file is actually a directory
        pub fn is_dir(&self) -> bool {
            self.get_metadata().is_dir(&self.file_name_raw)
        }

        /// Returns whether the file is actually a symbolic link
        pub fn is_symlink(&self) -> bool {
            self.unix_mode()
                .is_some_and(|mode| mode & ffi::S_IFLNK == ffi::S_IFLNK)
        }

        /// Returns whether the file is a normal file (i.e. not a directory or symlink)
        pub fn is_file(&self) -> bool {
            !self.is_dir() && !self.is_symlink()
        }

        /// Returns whether the file is read-only. (On Unix, this means it's not readable by
        /// *anyone*.)
        pub fn is_read_only(&self) -> bool {
            self.unix_mode().is_some_and(|mode| mode & 0o222 == 0)
        }

        /// Get unix mode for the file
        pub fn unix_mode(&self) -> Option<u32> {
            self.get_metadata().unix_mode()
        }

        /// Get the CRC32 hash of the original file
        pub fn crc32(&self) -> u32 {
            self.get_metadata().crc32
        }
    };
}
impl<'a> ZipFileEntryWithDataDescriptor<'a> {
    zip_file_methods!();

    /// Get the data descriptor
    pub fn data_descriptor(&self) -> &Option<ZipDataDescriptor> {
        &self.data_descriptor
    }
}

impl HasZipMetadata for ZipFileEntryWithDataDescriptor<'_> {
    fn get_metadata(&self) -> &ZipFileData {
        self.data.as_ref()
    }
}

impl<'a> ZipFileEntry<'a> {
    zip_file_methods!();

    /// Create a readable
    pub fn with_reader<R: Read + Seek>(
        self,
        reader: &'a mut R,
        options: ZipReadOptions<'_>,
    ) -> ZipResult<ZipFile<'a, R>> {
        let limit_reader = self.data.find_content(reader)?;

        let reader = self.data.make_reader(limit_reader, options)?;
        Ok(ZipFile {
            file_name_raw: self.file_name_raw,
            data: self.data,
            reader,
        })
    }
}

impl HasZipMetadata for ZipFileEntry<'_> {
    fn get_metadata(&self) -> &ZipFileData {
        self.data.as_ref()
    }
}

/// Methods for retrieving information on zip files
impl<'a, R: Read + ?Sized> ZipFile<'a, R> {
    zip_file_methods!();

    pub(crate) fn take_raw_reader(&mut self) -> io::Result<io::Take<&'a mut R>> {
        replace(&mut self.reader, ZipFileReader::NoReader).into_inner()
    }

    /// Prepare the path for extraction by creating necessary missing directories and checking for symlinks to be contained within the base path.
    ///
    /// `base_path` parameter is assumed to be canonicalized.
    pub(crate) fn safe_prepare_path(
        &self,
        base_path: &Path,
        outpath: &mut PathBuf,
        root_dir: Option<&(Vec<&OsStr>, impl RootDirFilter)>,
    ) -> ZipResult<()> {
        let file_name = self.name()?;
        let components = self
            .data
            .simplified_components(&file_name)
            .ok_or(invalid!("Invalid file path"))?;

        let components = match root_dir {
            Some((root_dir, filter)) => match components.strip_prefix(&**root_dir) {
                Some(components) => components,

                // In this case, we expect that the file was not in the root
                // directory, but was filtered out when searching for the
                // root directory.
                None => {
                    // We could technically find ourselves at this code
                    // path if the user provides an unstable or
                    // non-deterministic `filter` function.
                    //
                    // If debug assertions are on, we should panic here.
                    // Otherwise, the safest thing to do here is to just
                    // extract as-is.
                    debug_assert!(
                        !filter(&PathBuf::from_iter(components.iter())),
                        "Root directory filter should not match at this point"
                    );

                    // Extract as-is.
                    &components[..]
                }
            },

            None => &components[..],
        };

        *outpath = crate::path::resolve_enclosed(
            base_path,
            base_path,
            components.iter().map(|c| c.to_os_string()),
            true, // create intermediate directories
        )?;

        Ok(())
    }

    /// Get the extra data of the zip header for this file
    pub fn extra_data(&self) -> Option<Vec<u8>> {
        let out_buffer = Vec::new();
        let mut cursor = Cursor::new(out_buffer);
        let extra_fields = self.data.extra_fields.local_extra_fields();
        for one_extra_field in extra_fields {
            one_extra_field.write(&mut cursor, true).ok()?;
        }
        let extra_fields_data = cursor.into_inner();
        if extra_fields_data.is_empty() {
            None
        } else {
            Some(extra_fields_data)
        }
    }

    /// Get the starting offset of the data of the compressed file
    pub fn data_start(&self) -> Option<u64> {
        self.data.data_start.get().copied()
    }

    /// Get the [`SimpleFileOptions`] that would be used to write this file to
    /// a new zip archive.
    pub fn options(&self) -> SimpleFileOptions {
        let mut options = SimpleFileOptions::default()
            .large_file(self.compressed_size().max(self.size()) >= ZIP64_BYTES_THR)
            .compression_method(self.compression())
            .system(self.system())
            .external_attributes(self.external_attributes())
            .last_modified_time(
                self.last_modified()
                    .filter(DateTime::is_valid)
                    .unwrap_or_else(DateTime::default_for_write),
            );

        options.normalize();
        #[cfg(feature = "aes-crypto")]
        if let Some((mode, vendor_version)) = self.get_metadata().aes_settings() {
            use crate::write::options::EncryptWith;
            // Preserve AES metadata in options for downstream writers.
            // This is metadata-only and does not trigger encryption.
            options.encrypt_with = Some(EncryptWith::Aes {
                mode,
                vendor_version,
                salt: None,
                password: None,
            });
        }
        options
    }
}

/// Methods for retrieving information on zip files
impl<R: Read> ZipFile<'_, R> {
    /// iterate through all extra fields
    pub fn extra_data_fields(&self) -> impl Iterator<Item = &ExtraField> {
        self.data.extra_fields.inner.iter()
    }
}

impl<R: Read + ?Sized> HasZipMetadata for ZipFile<'_, R> {
    fn get_metadata(&self) -> &ZipFileData {
        self.data.as_ref()
    }
}

impl<R: Read + ?Sized> Read for ZipFile<'_, R> {
    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
        self.reader.read(buf)
    }

    fn read_to_end(&mut self, buf: &mut Vec<u8>) -> io::Result<usize> {
        self.reader.read_to_end(buf)
    }

    fn read_to_string(&mut self, buf: &mut String) -> io::Result<usize> {
        self.reader.read_to_string(buf)
    }

    fn read_exact(&mut self, buf: &mut [u8]) -> io::Result<()> {
        self.reader.read_exact(buf)
    }
}

impl<R: Read> Read for ZipFileSeek<'_, R> {
    fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
        match &mut self.reader {
            ZipFileSeekReader::Raw(r) => r.read(buf),
        }
    }
}

impl<R: Seek> Seek for ZipFileSeek<'_, R> {
    fn seek(&mut self, pos: SeekFrom) -> io::Result<u64> {
        match &mut self.reader {
            ZipFileSeekReader::Raw(r) => r.seek(pos),
        }
    }
}

impl<R> HasZipMetadata for ZipFileSeek<'_, R> {
    fn get_metadata(&self) -> &ZipFileData {
        self.data.as_ref()
    }
}

impl<'a, R> ZipFileSeek<'a, R> {
    zip_file_methods!();
}

impl<R: Read + ?Sized> Drop for ZipFile<'_, R> {
    fn drop(&mut self) {
        // self.data is Owned, this reader is constructed by a streaming reader.
        // In this case, we want to exhaust the reader so that the next file is accessible.
        if let Cow::Owned(_) = self.data {
            // Get the inner `Take` reader so all decryption, decompression and CRC calculation is skipped.
            if let Ok(mut inner) = self.take_raw_reader() {
                let _ = copy(&mut inner, &mut sink());
            }
        }
    }
}