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refactor
This commit is contained in:
Michael Greenberg
parent
2e9608555a
commit
2c0ff8526d
366
src/fs.rs
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366
src/fs.rs
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@ -0,0 +1,366 @@
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use std::collections::HashMap;
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use std::ffi::OsStr;
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use std::time::Duration;
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use fuser::{
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FileAttr, FileType, Filesystem, ReplyAttr, ReplyData, ReplyDirectory, ReplyEntry, Request,
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};
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use tracing::instrument;
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use serde_json::Value;
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#[derive(Debug)]
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pub struct FS {
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inodes: Vec<Option<Inode>>,
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timestamp: std::time::SystemTime,
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}
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const TTL: Duration = Duration::from_secs(300);
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#[derive(Debug)]
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pub struct Inode {
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parent: u64,
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inum: u64,
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entry: Entry,
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}
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#[derive(Debug)]
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pub enum Entry {
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File(String),
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Directory(DirType, HashMap<String, DirEntry>),
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}
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#[derive(Debug)]
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pub struct DirEntry {
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kind: FileType,
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inum: u64,
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}
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#[derive(Debug)]
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pub enum DirType {
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Named,
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List,
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}
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#[derive(Debug)]
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pub enum FSError {
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NoSuchInode(u64),
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InvalidInode(u64),
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}
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impl FS {
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fn get(&self, inum: u64) -> Result<&Inode, FSError> {
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let idx = inum as usize;
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if idx >= self.inodes.len() {
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return Err(FSError::NoSuchInode(inum));
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}
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match &self.inodes[idx] {
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None => Err(FSError::InvalidInode(inum)),
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Some(inode) => Ok(inode),
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}
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}
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pub fn attr(&self, inode: &Inode) -> FileAttr {
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let size = inode.entry.size();
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let kind = inode.entry.kind();
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let perm = if kind == FileType::Directory {
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0o755
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} else {
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0o644
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};
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FileAttr {
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ino: inode.inum,
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atime: self.timestamp,
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crtime: self.timestamp,
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ctime: self.timestamp,
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mtime: self.timestamp,
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nlink: 1,
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size,
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blksize: 1,
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blocks: size,
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kind,
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// TODO 2021-07-07 getpwnam upfront, store in fs
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uid: 501, // first user on macOS
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gid: 20, // staff on macOS
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perm,
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rdev: 0,
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padding: 0,
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flags: 0, // weird macOS thing
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}
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}
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}
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impl Entry {
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pub fn size(&self) -> u64 {
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match self {
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Entry::File(s) => s.len() as u64,
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Entry::Directory(DirType::Named, files) => {
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files.iter().map(|(name, _inum)| name.len() as u64).sum()
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}
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Entry::Directory(DirType::List, files) => files.len() as u64,
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}
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}
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pub fn kind(&self) -> FileType {
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match self {
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Entry::File(_) => FileType::RegularFile,
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Entry::Directory(..) => FileType::Directory,
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}
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}
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}
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impl Filesystem for FS {
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fn lookup(&mut self, _req: &Request, parent: u64, name: &OsStr, reply: ReplyEntry) {
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let dir = match self.get(parent) {
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Err(_e) => {
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reply.error(libc::ENOENT);
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return;
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}
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Ok(inode) => inode,
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};
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let filename = match name.to_str() {
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None => {
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reply.error(libc::ENOENT);
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return;
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}
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Some(name) => name,
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};
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match &dir.entry {
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Entry::Directory(_kind, files) => match files.get(filename) {
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None => {
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reply.error(libc::ENOENT);
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return;
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}
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Some(DirEntry { inum, .. }) => {
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let file = match self.get(*inum) {
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Err(_e) => {
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reply.error(libc::ENOENT);
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return;
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}
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Ok(inode) => inode,
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};
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reply.entry(&TTL, &self.attr(file), 0);
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return;
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}
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},
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_ => {
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reply.error(libc::ENOTDIR);
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return;
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}
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}
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}
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fn getattr(&mut self, _req: &Request, ino: u64, reply: ReplyAttr) {
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let file = match self.get(ino) {
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Err(_e) => {
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reply.error(libc::ENOENT);
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return;
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}
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Ok(inode) => inode,
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};
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reply.attr(&TTL, &self.attr(file));
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}
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fn read(
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&mut self,
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_req: &Request,
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ino: u64,
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_fh: u64,
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offset: i64,
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_size: u32,
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_flags: i32,
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_lock: Option<u64>,
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reply: ReplyData,
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) {
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let file = match self.get(ino) {
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Err(_e) => {
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reply.error(libc::ENOENT);
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return;
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}
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Ok(inode) => inode,
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};
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match &file.entry {
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Entry::File(s) => reply.data(&s.as_bytes()[offset as usize..]),
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_ => reply.error(libc::ENOENT),
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}
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}
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fn readdir(
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&mut self,
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_req: &Request,
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ino: u64,
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_fh: u64,
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offset: i64,
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mut reply: ReplyDirectory,
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) {
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let inode = match self.get(ino) {
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Err(_e) => {
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reply.error(libc::ENOENT);
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return;
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}
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Ok(inode) => inode,
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};
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match &inode.entry {
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Entry::File(_) => reply.error(libc::ENOTDIR),
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Entry::Directory(_kind, files) => {
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let dot_entries = vec![
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(ino, FileType::Directory, "."),
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(inode.parent, FileType::Directory, ".."),
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];
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let entries = files
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.into_iter()
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.map(|(filename, DirEntry { inum, kind })| (*inum, *kind, filename.as_str()));
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for (i, entry) in dot_entries
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.into_iter()
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.chain(entries)
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.into_iter()
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.enumerate()
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.skip(offset as usize)
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{
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if reply.add(entry.0, (i + 1) as i64, entry.1, entry.2) {
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break;
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}
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}
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reply.ok()
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}
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}
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}
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}
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fn kind(v: &Value) -> FileType {
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match v {
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Value::Object(_) | Value::Array(_) => FileType::Directory,
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_ => FileType::RegularFile,
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}
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}
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fn normalize_name(s: String) -> String {
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// inspired by https://en.wikipedia.org/wiki/Filename#Number_of_names_per_file
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s.replace(".", "dot")
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.replace("/", "slash")
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.replace("\\", "backslash")
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.replace("?", "question")
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.replace("*", "star")
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.replace(":", "colon")
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.replace("\"", "dquote")
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.replace("<", "lt")
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.replace(">", "gt")
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.replace(",", "comma")
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.replace(";", "semi")
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.replace("=", "equal")
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.replace(" ", "space")
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}
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impl From<Value> for FS {
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#[instrument(level = "info", skip(v))]
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fn from(v: Value) -> Self {
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let mut inodes: Vec<Option<Inode>> = Vec::new();
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// get zero-indexing for free, with a nice non-zero check to boot
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inodes.push(None);
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// TODO 2021-06-07 reserve based on guess or calculated size
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let mut next_id = fuser::FUSE_ROOT_ID;
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// parent inum, inum, value
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let mut worklist: Vec<(u64, u64, Value)> = Vec::new();
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if !(v.is_array() || v.is_object()) {
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panic!(
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"Unable to build a filesystem out of the primitive value '{}'",
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v
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);
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}
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worklist.push((next_id, next_id, v));
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next_id += 1;
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while !worklist.is_empty() {
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let (parent, inum, v) = worklist.pop().unwrap();
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let entry = match v {
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// TODO 2021-06-09 option to add newlines
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Value::Null => Entry::File("".into()),
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Value::Bool(b) => Entry::File(format!("{}", b)),
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Value::Number(n) => Entry::File(format!("{}", n)),
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Value::String(s) => Entry::File(s),
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Value::Array(vs) => {
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let mut children = HashMap::new();
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children.reserve(vs.len());
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let num_elts = vs.len() as f64;
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let width = num_elts.log10().ceil() as usize;
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for (i, child) in vs.into_iter().enumerate() {
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// TODO 2021-06-08 ability to turn off padding, add prefixes
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let name = format!("{:0width$}", i, width = width);
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children.insert(
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name,
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DirEntry {
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inum: next_id,
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kind: kind(&child),
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},
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);
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worklist.push((inum, next_id, child));
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next_id += 1;
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}
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Entry::Directory(DirType::List, children)
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}
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Value::Object(fvs) => {
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let mut children = HashMap::new();
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children.reserve(fvs.len());
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for (field, child) in fvs.into_iter() {
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let mut nfield = normalize_name(field);
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while children.contains_key(&nfield) {
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nfield.push('_');
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}
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// TODO 2021-06-08 log field vs. nfield
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children.insert(
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nfield,
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DirEntry {
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inum: next_id,
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kind: kind(&child),
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},
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);
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worklist.push((inum, next_id, child));
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next_id += 1;
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}
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Entry::Directory(DirType::Named, children)
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}
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};
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let idx = inum as usize;
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if idx >= inodes.len() {
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inodes.resize_with(idx + 1, || None);
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}
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inodes[idx] = Some(Inode {
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parent,
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inum,
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entry,
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});
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}
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assert_eq!(inodes.len() as u64, next_id);
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FS {
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inodes,
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timestamp: std::time::SystemTime::now(),
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}
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}
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}
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8
src/parse.rs
Normal file
8
src/parse.rs
Normal file
@ -0,0 +1,8 @@
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use serde_json::Value;
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use tracing::instrument;
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#[instrument(level = "info", skip(reader))]
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pub fn json(reader: Box<dyn std::io::BufRead>) -> Value {
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serde_json::from_reader(reader).expect("JSON")
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}
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