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|
use crate::directory::read_only_source::ReadOnlySource;
use crate::directory::{AntiCallToken, TerminatingWrite};
use byteorder::{ByteOrder, LittleEndian};
use crc32fast::Hasher;
use std::io;
use std::io::Write;
const COMMON_FOOTER_SIZE: usize = 4 * 5;
#[derive(Debug, Clone, PartialEq)]
pub struct Footer {
pub tantivy_version: (u32, u32, u32),
pub meta: String,
pub versioned_footer: VersionedFooter,
}
impl Footer {
pub fn new(versioned_footer: VersionedFooter) -> Self {
let tantivy_version = (
env!("CARGO_PKG_VERSION_MAJOR").parse().unwrap(),
env!("CARGO_PKG_VERSION_MINOR").parse().unwrap(),
env!("CARGO_PKG_VERSION_PATCH").parse().unwrap(),
);
Footer {
tantivy_version,
meta: format!(
"tantivy {}.{}.{}, index v{}",
tantivy_version.0,
tantivy_version.1,
tantivy_version.2,
versioned_footer.version()
),
versioned_footer,
}
}
pub fn to_bytes(&self) -> Vec<u8> {
let mut res = self.versioned_footer.to_bytes();
res.extend_from_slice(self.meta.as_bytes());
let len = res.len();
res.resize(len + COMMON_FOOTER_SIZE, 0);
let mut common_footer = &mut res[len..];
LittleEndian::write_u32(&mut common_footer, self.meta.len() as u32);
LittleEndian::write_u32(&mut common_footer[4..], self.tantivy_version.0);
LittleEndian::write_u32(&mut common_footer[8..], self.tantivy_version.1);
LittleEndian::write_u32(&mut common_footer[12..], self.tantivy_version.2);
LittleEndian::write_u32(&mut common_footer[16..], (len + COMMON_FOOTER_SIZE) as u32);
res
}
pub fn from_bytes(data: &[u8]) -> Result<Self, io::Error> {
let len = data.len();
if len < COMMON_FOOTER_SIZE + 4 {
// 4 bytes for index version, stored in versioned footer
return Err(io::Error::new(
io::ErrorKind::UnexpectedEof,
format!("File corrupted. The footer len must be over 24, while the entire file len is {}", len)
)
);
}
let size = LittleEndian::read_u32(&data[len - 4..]) as usize;
if len < size as usize {
return Err(io::Error::new(
io::ErrorKind::UnexpectedEof,
format!(
"File corrupted. The footer len is {}, while the entire file len is {}",
size, len
),
));
}
let footer = &data[len - size as usize..];
let meta_len = LittleEndian::read_u32(&footer[size - 20..]) as usize;
let tantivy_major = LittleEndian::read_u32(&footer[size - 16..]);
let tantivy_minor = LittleEndian::read_u32(&footer[size - 12..]);
let tantivy_patch = LittleEndian::read_u32(&footer[size - 8..]);
Ok(Footer {
tantivy_version: (tantivy_major, tantivy_minor, tantivy_patch),
meta: String::from_utf8_lossy(&footer[size - meta_len - 20..size - 20]).into_owned(),
versioned_footer: VersionedFooter::from_bytes(&footer[..size - meta_len - 20])?,
})
}
pub fn extract_footer(source: ReadOnlySource) -> Result<(Footer, ReadOnlySource), io::Error> {
let footer = Footer::from_bytes(source.as_slice())?;
let reader = source.slice_to(source.as_slice().len() - footer.size());
Ok((footer, reader))
}
pub fn size(&self) -> usize {
self.versioned_footer.size() as usize + self.meta.len() + 20
}
}
#[derive(Debug, Clone, PartialEq)]
pub enum VersionedFooter {
UnknownVersion { version: u32, size: u32 },
V0(u32), // crc
}
impl VersionedFooter {
pub fn to_bytes(&self) -> Vec<u8> {
match self {
VersionedFooter::V0(crc) => {
let mut res = vec![0; 8];
LittleEndian::write_u32(&mut res, 0);
LittleEndian::write_u32(&mut res[4..], *crc);
res
}
VersionedFooter::UnknownVersion { .. } => {
panic!("Unsupported index should never get serialized");
}
}
}
pub fn from_bytes(footer: &[u8]) -> Result<Self, io::Error> {
assert!(footer.len() >= 4);
let version = LittleEndian::read_u32(footer);
match version {
0 => {
if footer.len() == 8 {
Ok(VersionedFooter::V0(LittleEndian::read_u32(&footer[4..])))
} else {
Err(io::Error::new(
io::ErrorKind::UnexpectedEof,
format!(
"File corrupted. The versioned footer len is {}, while it should be 8",
footer.len()
),
))
}
}
version => Ok(VersionedFooter::UnknownVersion {
version,
size: footer.len() as u32,
}),
}
}
pub fn size(&self) -> u32 {
match self {
VersionedFooter::V0(_) => 8,
VersionedFooter::UnknownVersion { size, .. } => *size,
}
}
pub fn version(&self) -> u32 {
match self {
VersionedFooter::V0(_) => 0,
VersionedFooter::UnknownVersion { version, .. } => *version,
}
}
pub fn crc(&self) -> Option<u32> {
match self {
VersionedFooter::V0(crc) => Some(*crc),
VersionedFooter::UnknownVersion { .. } => None,
}
}
}
pub(crate) struct FooterProxy<W: TerminatingWrite> {
/// always Some except after terminate call
hasher: Option<Hasher>,
/// always Some except after terminate call
writer: Option<W>,
}
impl<W: TerminatingWrite> FooterProxy<W> {
pub fn new(writer: W) -> Self {
FooterProxy {
hasher: Some(Hasher::new()),
writer: Some(writer),
}
}
}
impl<W: TerminatingWrite> Write for FooterProxy<W> {
fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
let count = self.writer.as_mut().unwrap().write(buf)?;
self.hasher.as_mut().unwrap().update(&buf[..count]);
Ok(count)
}
fn flush(&mut self) -> io::Result<()> {
self.writer.as_mut().unwrap().flush()
}
}
impl<W: TerminatingWrite> TerminatingWrite for FooterProxy<W> {
fn terminate_ref(&mut self, _: AntiCallToken) -> io::Result<()> {
let crc = self.hasher.take().unwrap().finalize();
let footer = Footer::new(VersionedFooter::V0(crc)).to_bytes();
let mut writer = self.writer.take().unwrap();
writer.write_all(&footer)?;
writer.terminate()
}
}
#[cfg(test)]
mod tests {
use crate::directory::footer::{Footer, VersionedFooter};
#[test]
fn test_serialize_deserialize_footer() {
let crc = 123456;
let footer = Footer::new(VersionedFooter::V0(crc));
let footer_bytes = footer.to_bytes();
assert_eq!(Footer::from_bytes(&footer_bytes).unwrap(), footer);
}
}
|
