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use std::io::{self, Read, Write};
const HEADER_LEN: usize = 110;
const MAGIC_NUMBER: &[u8] = b"070701";
const TRAILER_NAME: &str = "TRAILER!!!";
pub struct Entry {
name: String,
ino: u32,
mode: u32,
uid: u32,
gid: u32,
nlink: u32,
mtime: u32,
file_size: u32,
dev_major: u32,
dev_minor: u32,
rdev_major: u32,
rdev_minor: u32,
}
pub struct Reader<R: Read> {
inner: R,
entry: Entry,
bytes_read: u32,
}
pub struct Builder {
name: String,
ino: u32,
mode: u32,
uid: u32,
gid: u32,
nlink: u32,
mtime: u32,
dev_major: u32,
dev_minor: u32,
rdev_major: u32,
rdev_minor: u32,
}
pub struct Writer<W: Write> {
inner: W,
written: u32,
file_size: u32,
header_size: usize,
header: Vec<u8>,
}
fn pad(len: usize) -> Option<Vec<u8>> {
let overhang = len % 4;
if overhang != 0 {
let repeat = 4 - overhang;
Some(vec![0u8; repeat])
} else {
None
}
}
fn read_hex_u32<R: Read>(reader: &mut R) -> io::Result<u32> {
let mut bytes = [0u8; 8];
try!(reader.read_exact(&mut bytes));
if let Ok(string) = ::std::str::from_utf8(&bytes) {
if let Ok(value) = u32::from_str_radix(string, 16) {
return Ok(value);
}
}
Err(io::Error::new(io::ErrorKind::InvalidData, "Invalid header field"))
}
impl Entry {
pub fn name(&self) -> &str { &self.name }
pub fn ino(&self) -> u32 { self.ino }
pub fn mode(&self) -> u32 { self.mode }
pub fn uid(&self) -> u32 { self.uid }
pub fn gid(&self) -> u32 { self.gid }
pub fn nlink(&self) -> u32 { self.nlink }
pub fn mtime(&self) -> u32 { self.mtime }
pub fn file_size(&self) -> u32 { self.file_size }
pub fn dev_major(&self) -> u32 { self.dev_major }
pub fn dev_minor(&self) -> u32 { self.dev_minor }
pub fn rdev_major(&self) -> u32 { self.rdev_major }
pub fn rdev_minor(&self) -> u32 { self.rdev_minor }
pub fn is_trailer(&self) -> bool { self.name == TRAILER_NAME }
}
impl<R: Read> Reader<R> {
pub fn new(mut inner: R) -> io::Result<Reader<R>> {
let mut magic = [0u8; 6];
try!(inner.read_exact(&mut magic));
if magic != MAGIC_NUMBER {
return Err(io::Error::new(io::ErrorKind::InvalidData,
"Invalid magic number"))
}
let ino = try!(read_hex_u32(&mut inner));
let mode = try!(read_hex_u32(&mut inner));
let uid = try!(read_hex_u32(&mut inner));
let gid = try!(read_hex_u32(&mut inner));
let nlink = try!(read_hex_u32(&mut inner));
let mtime = try!(read_hex_u32(&mut inner));
let file_size = try!(read_hex_u32(&mut inner));
let dev_major = try!(read_hex_u32(&mut inner));
let dev_minor = try!(read_hex_u32(&mut inner));
let rdev_major = try!(read_hex_u32(&mut inner));
let rdev_minor = try!(read_hex_u32(&mut inner));
let name_len = try!(read_hex_u32(&mut inner)) as usize;
let _checksum = try!(read_hex_u32(&mut inner));
let mut name_bytes = vec![0u8; name_len];
try!(inner.read_exact(&mut name_bytes));
if name_bytes.last() != Some(&0) {
return Err(io::Error::new(io::ErrorKind::InvalidData,
"Entry name was not NUL-terminated"))
}
name_bytes.pop();
let name = match String::from_utf8(name_bytes) {
Ok(name) => name,
Err(_) => {
return Err(io::Error::new(io::ErrorKind::InvalidData,
"Entry name was not valid UTF-8"))
}
};
if let Some(mut padding) = pad(HEADER_LEN + name_len) {
try!(inner.read_exact(&mut padding));
}
let entry = Entry {
name,
ino,
mode,
uid,
gid,
nlink,
mtime,
file_size,
dev_major,
dev_minor,
rdev_major,
rdev_minor,
};
Ok(Reader {
inner,
entry,
bytes_read: 0,
})
}
pub fn entry(&self) -> &Entry { &self.entry }
pub fn finish(mut self) -> io::Result<R> {
let remaining = self.entry.file_size - self.bytes_read;
if remaining > 0 {
try!(io::copy(&mut self.inner.by_ref().take(remaining as u64),
&mut io::sink()));
}
if let Some(mut padding) = pad(self.entry.file_size as usize) {
try!(self.inner.read_exact(&mut padding));
}
Ok(self.inner)
}
}
impl<R: Read> Read for Reader<R> {
fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
let remaining = self.entry.file_size - self.bytes_read;
let limit = buf.len().min(remaining as usize);
let num_bytes = try!(self.inner.read(&mut buf[..limit]));
self.bytes_read += num_bytes as u32;
Ok(num_bytes)
}
}
impl Builder {
pub fn new(name: &str) -> Builder {
Builder {
name: name.to_string(),
ino: 0,
mode: 0,
uid: 0,
gid: 0,
nlink: 1,
mtime: 0,
dev_major: 0,
dev_minor: 0,
rdev_major: 0,
rdev_minor: 0,
}
}
pub fn ino(mut self, ino: u32) -> Builder {
self.ino = ino;
self
}
pub fn mode(mut self, mode: u32) -> Builder {
self.mode = mode;
self
}
pub fn uid(mut self, uid: u32) -> Builder {
self.uid = uid;
self
}
pub fn gid(mut self, gid: u32) -> Builder {
self.gid = gid;
self
}
pub fn nlink(mut self, nlink: u32) -> Builder {
self.nlink = nlink;
self
}
pub fn mtime(mut self, mtime: u32) -> Builder {
self.mtime = mtime;
self
}
pub fn dev_major(mut self, dev_major: u32) -> Builder {
self.dev_major = dev_major;
self
}
pub fn dev_minor(mut self, dev_minor: u32) -> Builder {
self.dev_minor = dev_minor;
self
}
pub fn rdev_major(mut self, rdev_major: u32) -> Builder {
self.rdev_major = rdev_major;
self
}
pub fn rdev_minor(mut self, rdev_minor: u32) -> Builder {
self.rdev_minor = rdev_minor;
self
}
pub fn write<W: Write>(self, w: W, file_size: u32) -> Writer<W> {
let header = self.into_header(file_size);
Writer {
inner: w,
written: 0,
file_size: file_size,
header_size: header.len(),
header: header,
}
}
fn into_header(self, file_size: u32) -> Vec<u8> {
let mut header = Vec::with_capacity(HEADER_LEN);
header.extend(MAGIC_NUMBER);
header.extend(format!("{:08x}", self.ino).as_bytes());
header.extend(format!("{:08x}", self.mode).as_bytes());
header.extend(format!("{:08x}", self.uid).as_bytes());
header.extend(format!("{:08x}", self.gid).as_bytes());
header.extend(format!("{:08x}", self.nlink).as_bytes());
header.extend(format!("{:08x}", self.mtime).as_bytes());
header.extend(format!("{:08x}", file_size).as_bytes());
header.extend(format!("{:08x}", self.dev_major).as_bytes());
header.extend(format!("{:08x}", self.dev_minor).as_bytes());
header.extend(format!("{:08x}", self.rdev_major).as_bytes());
header.extend(format!("{:08x}", self.rdev_minor).as_bytes());
let name_len = self.name.len() + 1;
header.extend(format!("{:08x}", name_len).as_bytes());
header.extend(format!("{:08x}", 0).as_bytes());
header.extend(self.name.as_bytes());
header.push(0u8);
if let Some(pad) = pad(HEADER_LEN + name_len) {
header.extend(pad);
}
header
}
}
impl<W: Write> Writer<W> {
pub fn finish(mut self) -> io::Result<W> {
try!(self.do_finish());
Ok(self.inner)
}
fn try_write_header(&mut self) -> io::Result<()> {
if self.header.len() != 0 {
try!(self.inner.write_all(&self.header));
self.header.truncate(0);
}
Ok(())
}
fn do_finish(&mut self) -> io::Result<()> {
try!(self.try_write_header());
if self.written == self.file_size {
if let Some(pad) = pad(self.header_size + self.file_size as usize) {
try!(self.inner.write(&pad));
try!(self.inner.flush());
}
}
Ok(())
}
}
impl<W: Write> Write for Writer<W> {
fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
if self.written + buf.len() as u32 <= self.file_size {
try!(self.try_write_header());
let n = try!(self.inner.write(buf));
self.written += n as u32;
Ok(n)
} else {
Err(io::Error::new(io::ErrorKind::UnexpectedEof,
"trying to write more than the specified file size"))
}
}
fn flush(&mut self) -> io::Result<()> {
self.inner.flush()
}
}
pub fn trailer<W: Write>(w: W) -> io::Result<W> {
let b = Builder::new(TRAILER_NAME).nlink(0);
let writer = b.write(w, 0);
let w = try!(writer.finish());
Ok(w)
}
#[cfg(test)]
mod tests {
use super::*;
use std::io::{copy, Cursor};
#[test]
fn test_single_file() {
let data: &[u8] = b"Hello, World";
let length = data.len() as u32;
let mut input = Cursor::new(data);
let output = vec![];
let b = Builder::new("./hello_world");
let mut writer = b.write(output, length);
copy(&mut input, &mut writer).unwrap();
let output = writer.finish().unwrap();
let output = trailer(output).unwrap();
let mut reader = Reader::new(output.as_slice()).unwrap();
assert_eq!(reader.entry.name(), "./hello_world");
assert_eq!(reader.entry.file_size(), length);
let mut contents = vec![];
copy(&mut reader, &mut contents).unwrap();
assert_eq!(contents, data);
let reader = Reader::new(reader.finish().unwrap()).unwrap();
assert!(reader.entry().is_trailer());
}
#[test]
fn test_multi_file() {
let data1: &[u8] = b"Hello, World";
let length1 = data1.len() as u32;
let mut input1 = Cursor::new(data1);
let data2: &[u8] = b"Hello, World 2";
let length2 = data2.len() as u32;
let mut input2 = Cursor::new(data2);
let output = vec![];
let b = Builder::new("./hello_world")
.ino(1)
.uid(1000)
.gid(1000)
.mode(0o100644);
let mut writer = b.write(output, length1);
copy(&mut input1, &mut writer).unwrap();
let output = writer.finish().unwrap();
let b = Builder::new("./hello_world2")
.ino(2)
.uid(1000)
.gid(1000)
.mode(0o100644);
let mut writer = b.write(output, length2);
copy(&mut input2, &mut writer).unwrap();
let output = writer.finish().unwrap();
let output = trailer(output).unwrap();
let mut reader = Reader::new(output.as_slice()).unwrap();
assert_eq!(reader.entry().name(), "./hello_world");
assert_eq!(reader.entry().file_size(), length1);
assert_eq!(reader.entry().ino(), 1);
assert_eq!(reader.entry().uid(), 1000);
assert_eq!(reader.entry().gid(), 1000);
assert_eq!(reader.entry().mode(), 0o100644);
let mut contents = vec![];
copy(&mut reader, &mut contents).unwrap();
assert_eq!(contents, data1);
let mut reader = Reader::new(reader.finish().unwrap()).unwrap();
assert_eq!(reader.entry().name(), "./hello_world2");
assert_eq!(reader.entry().file_size(), length2);
assert_eq!(reader.entry().ino(), 2);
let mut contents = vec![];
copy(&mut reader, &mut contents).unwrap();
assert_eq!(contents, data2);
let reader = Reader::new(reader.finish().unwrap()).unwrap();
assert!(reader.entry().is_trailer());
}
}