Index parsing and gitignore files
This commit is contained in:
Antonin Ruan
+402
-37
@@ -1,56 +1,421 @@
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use std::{
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io::{
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self,
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Error,
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},
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};
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use anyhow::Result;
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use anyhow::bail;
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use sha1::{Digest, Sha1};
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use std::fs;
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use std::{ffi::CStr, fmt::Display, fs::File, io::prelude::*, os::unix::fs::PermissionsExt};
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use crate::GIT_DIR;
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use crate::git_fs::get_git_root;
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#[derive(Debug)]
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#[derive(Clone, Debug, PartialEq)]
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pub enum ObjectType {
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Regular,
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SymLink,
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GitLink,
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}
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impl Display for ObjectType {
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fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
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match &self {
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Self::Regular => write!(f, "Regular"),
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Self::SymLink => write!(f, "Symlink"),
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Self::GitLink => write!(f, "Gitlink"),
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}
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}
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}
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#[derive(Clone, Debug, PartialEq)]
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pub struct IndexEntry {
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file_size: u32,
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object_type: ObjectType,
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permissions: u16,
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hash: [u8; 20],
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name: String,
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}
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impl IndexEntry {
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fn from_bytes(bytes: Vec<u8>) -> io::Result<Self> {
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fn from_bytes(bytes: &[u8]) -> Result<(Self, usize)> {
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let mode = &bytes[24..28];
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let ot_bin = mode[2] >> 4;
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let object_type = match ot_bin {
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0b1000 => ObjectType::Regular,
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0b1010 => ObjectType::SymLink,
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0b1110 => ObjectType::GitLink,
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_ => bail!("Invalid object type: {}", ot_bin),
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};
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let permissions = u16::from_be_bytes(mode[2..4].try_into()?) & !0xFE00;
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match (permissions, &object_type) {
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(0, ObjectType::GitLink) => (),
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(0, ObjectType::SymLink) => (),
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(0o755, ObjectType::Regular) => (),
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(0o644, ObjectType::Regular) => (),
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_ => bail!(
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"Invalid permissions (0o{:o}) for type {}",
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permissions,
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object_type
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),
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};
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return Err(Error::other("Not implemented"))
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let hash: [u8; 20] = bytes[40..60].try_into()?;
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let cname = CStr::from_bytes_until_nul(&bytes[62..])?;
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let name = String::from(cname.to_str()?);
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let entry_size = usize::div_ceil(62 + cname.count_bytes(), 8) * 8;
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Ok((
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IndexEntry {
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object_type,
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permissions,
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hash,
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name,
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},
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entry_size,
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))
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}
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fn to_bytes(&self) -> Result<Vec<u8>> {
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let mut bytes = Vec::new();
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// ctime
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bytes.extend([0, 0, 0, 0]);
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// ctime nano
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bytes.extend([0, 0, 0, 0]);
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// mtime
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bytes.extend([0, 0, 0, 0]);
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// mtime nano
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bytes.extend([0, 0, 0, 0]);
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// dev
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bytes.extend([0, 0, 0, 0]);
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// ino
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bytes.extend([0, 0, 0, 0]);
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// mode
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let ot_bin: u16 = match self.object_type {
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ObjectType::Regular => 0b1000,
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ObjectType::SymLink => 0b1010,
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ObjectType::GitLink => 0b1110,
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};
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let perms: u16 = self.permissions | (ot_bin << 12);
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bytes.extend([0, 0]);
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bytes.extend(perms.to_be_bytes());
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// uid
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bytes.extend([0, 0, 0, 0]);
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// gid
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bytes.extend([0, 0, 0, 0]);
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// file size
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bytes.extend([0, 0, 0, 0]);
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// object name
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bytes.extend(self.hash);
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// flags
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let flags = u16::min(0xFFF, self.name.len() as u16);
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bytes.extend(flags.to_be_bytes());
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// entry path name
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bytes.extend(self.name.as_bytes());
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let padding = ((bytes.len() + 1).div_ceil(8) * 8) - bytes.len();
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bytes.extend(vec![0; padding]);
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Ok(bytes)
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}
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}
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#[derive(Debug)]
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#[derive(Debug, PartialEq)]
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pub struct Index {
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version: u32,
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entries: Vec<IndexEntry>,
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}
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impl Index {
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pub fn from_bytes(bytes: Vec<u8>) -> io::Result<Self> {
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let magic: [u8; 4] = match bytes.first_chunk() {
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None => return Err(Error::other("Error parsing index")),
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Some(magic) => *magic,
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};
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match str::from_utf8(&magic) {
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Ok("DIRC") => (),
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_ => return Err(Error::other("Invalid index"))
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};
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let version_bytes = <[u8; 4]>::try_from(&bytes.as_slice()[4..8]).unwrap();
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let version = u32::from_be_bytes(version_bytes);
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let count_bytes = <[u8; 4]>::try_from(&bytes.as_slice()[8..12]).unwrap();
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let count = u32::from_be_bytes(count_bytes);
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let entries: Vec<IndexEntry> = Vec::with_capacity(usize::try_from(count).unwrap());
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for i in 0..=count {
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};
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return Ok(Index { version, entries});
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impl Default for Index {
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fn default() -> Self {
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Index {
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version: 2,
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entries: Vec::new(),
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}
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}
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}
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impl Index {
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pub fn load() -> Result<Self> {
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let path = get_git_root()?.join("index");
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if !path.exists() {
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return Ok(Index {
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version: 2u32,
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entries: Vec::new(),
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});
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}
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let mut file = File::open(&path)?;
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let mut content: Vec<u8> = Vec::new();
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file.read_to_end(&mut content)?;
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Index::from_bytes(content)
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}
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pub fn save(&self) -> Result<()> {
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let path = get_git_root()?.join("index");
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let mut file = File::create(&path)?;
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file.write_all(&self.to_bytes()?)?;
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Ok(())
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}
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fn insert_entry(&mut self, entry: IndexEntry) {
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match self
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.entries
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.binary_search_by_key(&entry.name, |e| e.name.clone())
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{
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Ok(pos) => self.entries[pos] = entry,
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Err(pos) => self.entries.insert(pos, entry),
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}
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}
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pub fn add_file(&mut self, name: String, hash: [u8; 20]) -> Result<()> {
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let metadata = fs::metadata(&name)?;
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if metadata.is_dir() {
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bail!("Cannot add a directory to index")
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};
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let object_type = if metadata.is_symlink() {
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ObjectType::SymLink
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} else {
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ObjectType::Regular
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};
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let permissions = (metadata.permissions().mode() as u16) & !0xFE00;
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let entry = IndexEntry {
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name,
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hash,
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object_type,
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permissions,
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};
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self.insert_entry(entry);
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Ok(())
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}
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pub fn remove_file(&mut self, name: String) -> Result<()> {
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let entry = IndexEntry {
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name: name.clone(),
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hash: [0u8; 20],
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object_type: ObjectType::Regular,
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permissions: 0,
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};
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match self
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.entries
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.binary_search_by_key(&entry.name, |a| a.name.clone())
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{
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Ok(pos) => self.entries.remove(pos),
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Err(_) => bail!("No file {} in index", name),
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};
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Ok(())
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}
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fn from_bytes(bytes: Vec<u8>) -> Result<Self> {
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match &bytes[0..4] {
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b"DIRC" => (),
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_ => bail!("Invalid index signature"),
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};
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let version = u32::from_be_bytes(bytes[4..8].try_into()?);
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let count = u32::from_be_bytes(bytes[8..12].try_into()?);
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let mut entries: Vec<IndexEntry> = Vec::with_capacity(usize::try_from(count)?);
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let mut offset = 12;
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for _i in 0..count {
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let (entry, entry_size) = IndexEntry::from_bytes(&bytes[offset..])?;
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offset += entry_size;
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entries.push(entry);
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}
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let mut hasher = Sha1::new();
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hasher.update(&bytes[..offset]);
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let hash = hasher.finalize();
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if bytes[offset..] != *hash {
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bail!("Index does not match its checksum")
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}
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Ok(Index { version, entries })
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}
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fn to_bytes(&self) -> Result<Vec<u8>> {
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let mut bytes: Vec<u8> = Vec::new();
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bytes.extend("DIRC".as_bytes());
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bytes.extend(self.version.to_be_bytes());
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let count: u32 = self.entries.len() as u32;
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bytes.extend(count.to_be_bytes());
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for entry in &self.entries {
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bytes.extend(entry.to_bytes()?);
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}
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let mut hasher = Sha1::new();
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hasher.update(&bytes);
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let hash = hasher.finalize();
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bytes.extend(hash);
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Ok(bytes)
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}
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}
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#[cfg(test)]
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mod tests {
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use super::*;
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#[test]
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fn index_entry_to_bytes() {
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let entry1 = IndexEntry {
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object_type: ObjectType::Regular,
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permissions: 0o644u16,
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hash: [0x19u8; 20],
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name: String::from("src/git_fs/head.rs"),
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};
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let expected1: Vec<u8> = vec![
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0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
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0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x81, 0xa4,
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0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x19, 0x19,
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0x19, 0x19, 0x19, 0x19, 0x19, 0x19, 0x19, 0x19, 0x19, 0x19, 0x19, 0x19, 0x19, 0x19,
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0x19, 0x19, 0x19, 0x19, 0x00, 0x12, 0x73, 0x72, 0x63, 0x2f, 0x67, 0x69, 0x74, 0x5f,
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0x66, 0x73, 0x2f, 0x68, 0x65, 0x61, 0x64, 0x2e, 0x72, 0x73, 0x00, 0x00, 0x00, 0x00,
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0x00, 0x00, 0x00, 0x00,
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];
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let entry2 = IndexEntry {
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object_type: ObjectType::GitLink,
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permissions: 0,
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hash: [0x19u8; 20],
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name: String::from("src/git_fs/head.r"),
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};
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let expected2: Vec<u8> = vec![
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0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
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0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xE0, 0x00,
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0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x19, 0x19,
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0x19, 0x19, 0x19, 0x19, 0x19, 0x19, 0x19, 0x19, 0x19, 0x19, 0x19, 0x19, 0x19, 0x19,
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0x19, 0x19, 0x19, 0x19, 0x00, 0x11, 0x73, 0x72, 0x63, 0x2f, 0x67, 0x69, 0x74, 0x5f,
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0x66, 0x73, 0x2f, 0x68, 0x65, 0x61, 0x64, 0x2e, 0x72, 0x00,
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];
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let entry3 = IndexEntry {
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object_type: ObjectType::SymLink,
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permissions: 0,
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hash: [0x19u8; 20],
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name: String::from("src/git_fs/head.rst"),
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};
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let expected3: Vec<u8> = vec![
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0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
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0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xA0, 0x00,
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0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x19, 0x19,
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0x19, 0x19, 0x19, 0x19, 0x19, 0x19, 0x19, 0x19, 0x19, 0x19, 0x19, 0x19, 0x19, 0x19,
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0x19, 0x19, 0x19, 0x19, 0x00, 0x13, 0x73, 0x72, 0x63, 0x2f, 0x67, 0x69, 0x74, 0x5f,
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0x66, 0x73, 0x2f, 0x68, 0x65, 0x61, 0x64, 0x2e, 0x72, 0x73, 0x74, 0x00, 0x00, 0x00,
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0x00, 0x00, 0x00, 0x00,
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];
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assert_eq!(entry1.to_bytes().unwrap(), expected1);
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assert_eq!(entry2.to_bytes().unwrap(), expected2);
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assert_eq!(entry3.to_bytes().unwrap(), expected3);
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}
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#[test]
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fn index_entry_from_bytes() {
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let expected1 = IndexEntry {
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object_type: ObjectType::Regular,
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permissions: 0o644u16,
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hash: [0x19u8; 20],
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name: String::from("src/git_fs/head.rs"),
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};
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let (entry1, _) = IndexEntry::from_bytes(&vec![
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0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
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0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x81, 0xa4,
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0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x19, 0x19,
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0x19, 0x19, 0x19, 0x19, 0x19, 0x19, 0x19, 0x19, 0x19, 0x19, 0x19, 0x19, 0x19, 0x19,
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0x19, 0x19, 0x19, 0x19, 0x00, 0x12, 0x73, 0x72, 0x63, 0x2f, 0x67, 0x69, 0x74, 0x5f,
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0x66, 0x73, 0x2f, 0x68, 0x65, 0x61, 0x64, 0x2e, 0x72, 0x73, 0x00, 0x00, 0x00, 0x00,
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0x00, 0x00, 0x00, 0x00,
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])
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.unwrap();
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let expected2 = IndexEntry {
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object_type: ObjectType::GitLink,
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permissions: 0,
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hash: [0x19u8; 20],
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name: String::from("src/git_fs/head.r"),
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};
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let (entry2, _) = IndexEntry::from_bytes(&vec![
|
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0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
|
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0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xE0, 0x00,
|
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0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x19, 0x19,
|
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0x19, 0x19, 0x19, 0x19, 0x19, 0x19, 0x19, 0x19, 0x19, 0x19, 0x19, 0x19, 0x19, 0x19,
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0x19, 0x19, 0x19, 0x19, 0x00, 0x11, 0x73, 0x72, 0x63, 0x2f, 0x67, 0x69, 0x74, 0x5f,
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0x66, 0x73, 0x2f, 0x68, 0x65, 0x61, 0x64, 0x2e, 0x72, 0x00,
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])
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.unwrap();
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let expected3 = IndexEntry {
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object_type: ObjectType::SymLink,
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permissions: 0,
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hash: [0x19u8; 20],
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name: String::from("src/git_fs/head.rst"),
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};
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let (entry3, _) = IndexEntry::from_bytes(&vec![
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0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
|
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0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xA0, 0x00,
|
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0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x19, 0x19,
|
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0x19, 0x19, 0x19, 0x19, 0x19, 0x19, 0x19, 0x19, 0x19, 0x19, 0x19, 0x19, 0x19, 0x19,
|
||||
0x19, 0x19, 0x19, 0x19, 0x00, 0x13, 0x73, 0x72, 0x63, 0x2f, 0x67, 0x69, 0x74, 0x5f,
|
||||
0x66, 0x73, 0x2f, 0x68, 0x65, 0x61, 0x64, 0x2e, 0x72, 0x73, 0x74, 0x00, 0x00, 0x00,
|
||||
0x00, 0x00, 0x00, 0x00,
|
||||
])
|
||||
.unwrap();
|
||||
|
||||
assert_eq!(entry1, expected1);
|
||||
assert_eq!(entry2, expected2);
|
||||
assert_eq!(entry3, expected3);
|
||||
}
|
||||
|
||||
#[test]
|
||||
fn index_insert_entry() {
|
||||
let mut index = Index::default();
|
||||
|
||||
let entry1 = IndexEntry {
|
||||
object_type: ObjectType::Regular,
|
||||
permissions: 0o644u16,
|
||||
hash: [0x19u8; 20],
|
||||
name: String::from("a"),
|
||||
};
|
||||
let entry2 = IndexEntry {
|
||||
object_type: ObjectType::Regular,
|
||||
permissions: 0o644u16,
|
||||
hash: [0x19u8; 20],
|
||||
name: String::from("b"),
|
||||
};
|
||||
let entry3 = IndexEntry {
|
||||
object_type: ObjectType::SymLink,
|
||||
permissions: 0,
|
||||
hash: [0x19u8; 20],
|
||||
name: String::from(".hello"),
|
||||
};
|
||||
let entry4 = IndexEntry {
|
||||
object_type: ObjectType::Regular,
|
||||
permissions: 0o644u16,
|
||||
hash: [0x20u8; 20],
|
||||
name: String::from("b"),
|
||||
};
|
||||
|
||||
index.insert_entry(entry1.clone());
|
||||
index.insert_entry(entry2.clone());
|
||||
index.insert_entry(entry3.clone());
|
||||
index.insert_entry(entry4.clone());
|
||||
|
||||
let expected = Index {
|
||||
entries: vec![entry3, entry1, entry4],
|
||||
..Default::default()
|
||||
};
|
||||
|
||||
assert_eq!(index, expected);
|
||||
}
|
||||
}
|
||||
|
||||
Reference in New Issue
Block a user