zip-rs-wasm/src/spec.rs
2024-05-02 17:50:27 -07:00

239 lines
9.1 KiB
Rust

use crate::result::{ZipError, ZipResult};
use crate::unstable::{LittleEndianReadExt, LittleEndianWriteExt};
use std::borrow::Cow;
use std::io;
use std::io::prelude::*;
use std::path::{Component, Path};
pub const LOCAL_FILE_HEADER_SIGNATURE: u32 = 0x04034b50;
pub const CENTRAL_DIRECTORY_HEADER_SIGNATURE: u32 = 0x02014b50;
pub(crate) const CENTRAL_DIRECTORY_END_SIGNATURE: u32 = 0x06054b50;
pub const ZIP64_CENTRAL_DIRECTORY_END_SIGNATURE: u32 = 0x06064b50;
pub(crate) const ZIP64_CENTRAL_DIRECTORY_END_LOCATOR_SIGNATURE: u32 = 0x07064b50;
pub const ZIP64_BYTES_THR: u64 = u32::MAX as u64;
pub const ZIP64_ENTRY_THR: usize = u16::MAX as usize;
pub struct CentralDirectoryEnd {
pub disk_number: u16,
pub disk_with_central_directory: u16,
pub number_of_files_on_this_disk: u16,
pub number_of_files: u16,
pub central_directory_size: u32,
pub central_directory_offset: u32,
pub zip_file_comment: Vec<u8>,
}
impl CentralDirectoryEnd {
pub fn parse<T: Read>(reader: &mut T) -> ZipResult<CentralDirectoryEnd> {
let magic = reader.read_u32_le()?;
if magic != CENTRAL_DIRECTORY_END_SIGNATURE {
return Err(ZipError::InvalidArchive("Invalid digital signature header"));
}
let disk_number = reader.read_u16_le()?;
let disk_with_central_directory = reader.read_u16_le()?;
let number_of_files_on_this_disk = reader.read_u16_le()?;
let number_of_files = reader.read_u16_le()?;
let central_directory_size = reader.read_u32_le()?;
let central_directory_offset = reader.read_u32_le()?;
let zip_file_comment_length = reader.read_u16_le()? as usize;
let mut zip_file_comment = vec![0; zip_file_comment_length];
reader.read_exact(&mut zip_file_comment)?;
Ok(CentralDirectoryEnd {
disk_number,
disk_with_central_directory,
number_of_files_on_this_disk,
number_of_files,
central_directory_size,
central_directory_offset,
zip_file_comment,
})
}
pub fn find_and_parse<T: Read + Seek>(reader: &mut T) -> ZipResult<(CentralDirectoryEnd, u64)> {
const HEADER_SIZE: u64 = 22;
const BYTES_BETWEEN_MAGIC_AND_COMMENT_SIZE: u64 = HEADER_SIZE - 6;
let file_length = reader.seek(io::SeekFrom::End(0))?;
let search_upper_bound = file_length.saturating_sub(HEADER_SIZE + u16::MAX as u64);
if file_length < HEADER_SIZE {
return Err(ZipError::InvalidArchive("Invalid zip header"));
}
let mut pos = file_length - HEADER_SIZE;
while pos >= search_upper_bound {
reader.seek(io::SeekFrom::Start(pos))?;
if reader.read_u32_le()? == CENTRAL_DIRECTORY_END_SIGNATURE {
reader.seek(io::SeekFrom::Current(
BYTES_BETWEEN_MAGIC_AND_COMMENT_SIZE as i64,
))?;
let cde_start_pos = reader.seek(io::SeekFrom::Start(pos))?;
if let Ok(end_header) = CentralDirectoryEnd::parse(reader) {
return Ok((end_header, cde_start_pos));
}
}
pos = match pos.checked_sub(1) {
Some(p) => p,
None => break,
};
}
Err(ZipError::InvalidArchive(
"Could not find central directory end",
))
}
pub fn write<T: Write>(&self, writer: &mut T) -> ZipResult<()> {
writer.write_u32_le(CENTRAL_DIRECTORY_END_SIGNATURE)?;
writer.write_u16_le(self.disk_number)?;
writer.write_u16_le(self.disk_with_central_directory)?;
writer.write_u16_le(self.number_of_files_on_this_disk)?;
writer.write_u16_le(self.number_of_files)?;
writer.write_u32_le(self.central_directory_size)?;
writer.write_u32_le(self.central_directory_offset)?;
writer.write_u16_le(self.zip_file_comment.len() as u16)?;
writer.write_all(&self.zip_file_comment)?;
Ok(())
}
}
pub struct Zip64CentralDirectoryEndLocator {
pub disk_with_central_directory: u32,
pub end_of_central_directory_offset: u64,
pub number_of_disks: u32,
}
impl Zip64CentralDirectoryEndLocator {
pub fn parse<T: Read>(reader: &mut T) -> ZipResult<Zip64CentralDirectoryEndLocator> {
let magic = reader.read_u32_le()?;
if magic != ZIP64_CENTRAL_DIRECTORY_END_LOCATOR_SIGNATURE {
return Err(ZipError::InvalidArchive(
"Invalid zip64 locator digital signature header",
));
}
let disk_with_central_directory = reader.read_u32_le()?;
let end_of_central_directory_offset = reader.read_u64_le()?;
let number_of_disks = reader.read_u32_le()?;
Ok(Zip64CentralDirectoryEndLocator {
disk_with_central_directory,
end_of_central_directory_offset,
number_of_disks,
})
}
pub fn write<T: Write>(&self, writer: &mut T) -> ZipResult<()> {
writer.write_u32_le(ZIP64_CENTRAL_DIRECTORY_END_LOCATOR_SIGNATURE)?;
writer.write_u32_le(self.disk_with_central_directory)?;
writer.write_u64_le(self.end_of_central_directory_offset)?;
writer.write_u32_le(self.number_of_disks)?;
Ok(())
}
}
pub struct Zip64CentralDirectoryEnd {
pub version_made_by: u16,
pub version_needed_to_extract: u16,
pub disk_number: u32,
pub disk_with_central_directory: u32,
pub number_of_files_on_this_disk: u64,
pub number_of_files: u64,
pub central_directory_size: u64,
pub central_directory_offset: u64,
//pub extensible_data_sector: Vec<u8>, <-- We don't do anything with this at the moment.
}
impl Zip64CentralDirectoryEnd {
pub fn find_and_parse<T: Read + Seek>(
reader: &mut T,
nominal_offset: u64,
search_upper_bound: u64,
) -> ZipResult<Vec<(Zip64CentralDirectoryEnd, u64)>> {
let mut results = Vec::new();
let mut pos = search_upper_bound;
while pos >= nominal_offset {
reader.seek(io::SeekFrom::Start(pos))?;
if reader.read_u32_le()? == ZIP64_CENTRAL_DIRECTORY_END_SIGNATURE {
let archive_offset = pos - nominal_offset;
let _record_size = reader.read_u64_le()?;
// We would use this value if we did anything with the "zip64 extensible data sector".
let version_made_by = reader.read_u16_le()?;
let version_needed_to_extract = reader.read_u16_le()?;
let disk_number = reader.read_u32_le()?;
let disk_with_central_directory = reader.read_u32_le()?;
let number_of_files_on_this_disk = reader.read_u64_le()?;
let number_of_files = reader.read_u64_le()?;
let central_directory_size = reader.read_u64_le()?;
let central_directory_offset = reader.read_u64_le()?;
results.push((
Zip64CentralDirectoryEnd {
version_made_by,
version_needed_to_extract,
disk_number,
disk_with_central_directory,
number_of_files_on_this_disk,
number_of_files,
central_directory_size,
central_directory_offset,
},
archive_offset,
));
}
if pos > 0 {
pos -= 1;
} else {
break;
}
}
if results.is_empty() {
Err(ZipError::InvalidArchive(
"Could not find ZIP64 central directory end",
))
} else {
Ok(results)
}
}
pub fn write<T: Write>(&self, writer: &mut T) -> ZipResult<()> {
writer.write_u32_le(ZIP64_CENTRAL_DIRECTORY_END_SIGNATURE)?;
writer.write_u64_le(44)?; // record size
writer.write_u16_le(self.version_made_by)?;
writer.write_u16_le(self.version_needed_to_extract)?;
writer.write_u32_le(self.disk_number)?;
writer.write_u32_le(self.disk_with_central_directory)?;
writer.write_u64_le(self.number_of_files_on_this_disk)?;
writer.write_u64_le(self.number_of_files)?;
writer.write_u64_le(self.central_directory_size)?;
writer.write_u64_le(self.central_directory_offset)?;
Ok(())
}
}
/// Converts a path to the ZIP format (forward-slash-delimited and normalized).
pub(crate) fn path_to_string<T: AsRef<Path>>(path: T) -> String {
let mut normalized_components = Vec::new();
// Empty element ensures the path has a leading slash, with no extra allocation after the join
normalized_components.push(Cow::Borrowed(""));
for component in path.as_ref().components() {
match component {
Component::Normal(os_str) => {
normalized_components.push(os_str.to_string_lossy());
}
Component::ParentDir => {
if normalized_components.len() > 1 {
normalized_components.pop();
}
}
_ => {}
}
}
normalized_components.join("/")
}