memfs/
memfs.rs

1use simply_fuse::attrs::{FileAttributes, SetFileAttributes};
2use simply_fuse::basic::*;
3use simply_fuse::error::{FSError, FSResult as Result};
4use simply_fuse::*;
5
6use std::ffi::OsStr;
7use std::io::BufRead;
8use std::path::Path;
9
10const TEST_MSG: &str = "hello_world!";
11
12fn main() -> Result<(), Box<dyn std::error::Error>> {
13    let mount = &Path::new("./memfs-mount/");
14    let _ = std::fs::create_dir(mount);
15
16    let mut fs = MemFS::new();
17    fs.inodes
18        .push_entry(ROOT_INODE, "test".into(), Directory::default());
19
20    fs.inodes
21        .push_entry(2u64.into(), "test2".into(), Directory::default());
22
23    fs.inodes
24        .push_entry(3u64.into(), "test3".into(), Directory::default());
25
26    fs.inodes
27        .push_entry(1u64.into(), "root2".into(), Directory::default());
28
29    fs.inodes.push_entry(
30        ROOT_INODE,
31        "file".into(),
32        File::new(TEST_MSG.as_bytes().into()),
33    );
34
35    let mut r = Runner::new(fs, mount);
36    println!("{:#?}", r);
37    r.run_block()?;
38
39    Ok(())
40}
41
42#[derive(Debug)]
43pub struct File {
44    pub data: Vec<u8>,
45    pub attrs: FileAttributes,
46}
47
48impl File {
49    fn new(data: Vec<u8>) -> File {
50        File {
51            attrs: FileAttributes::builder()
52                .size(data.len() as u64)
53                .mode(libc::S_IFREG | 0o755)
54                .build(),
55
56            data,
57        }
58    }
59
60    fn size(&self) -> usize {
61        self.attrs.size() as usize
62    }
63}
64
65impl Attributable for File {
66    fn getattrs(&self) -> FileAttributes {
67        self.attrs
68    }
69}
70
71impl Filelike for File {}
72
73#[derive(Debug)]
74struct MemFS {
75    inodes: INodeTable<File>,
76}
77
78impl MemFS {
79    fn new() -> MemFS {
80        MemFS {
81            inodes: INodeTable::default(),
82        }
83    }
84}
85
86impl Filesystem for MemFS {
87    fn lookup(&mut self, parent: INode, name: &OsStr) -> Result<Lookup> {
88        let parent = self
89            .inodes
90            .get(parent)
91            .ok_or(FSError::NoEntry)
92            .and_then(|x| x.as_dir().ok_or(FSError::NotDirectory))?;
93
94        let (child_ino, child) = parent
95            .get(name)
96            // get the inode entry and then map it into (inode, &entry)
97            .and_then(|ino| self.inodes.get(*ino).map(|x| (*ino, x)))
98            .ok_or(FSError::NoEntry)?;
99
100        Ok(Lookup::builder()
101            .attributes(child.getattrs())
102            .inode(child_ino)
103            .build())
104    }
105
106    fn getattr(&mut self, inode: INode) -> Result<FileAttributes> {
107        let entry = self.inodes.get(inode).ok_or(FSError::NoEntry)?;
108
109        Ok(entry.getattrs())
110    }
111
112    fn readdir(&mut self, dir_ino: INode, offset: u64) -> Result<Vec<DirEntry>> {
113        let dir_main = self.inodes.get(dir_ino).ok_or(FSError::NoEntry)?;
114        let dir = dir_main.as_dir().ok_or(FSError::NotDirectory)?;
115
116        let dots = [
117            DirEntry::builder()
118                .name(".".into())
119                .inode(dir_ino)
120                .typ(FileType::Directory)
121                .offset(1)
122                .build(),
123            DirEntry::builder()
124                .name("..".into())
125                .inode(dir_main.parent().unwrap_or(ROOT_INODE))
126                .typ(FileType::Directory)
127                .offset(2)
128                .build(),
129        ];
130
131        Ok(dots
132            .into_iter()
133            .chain(
134                dir.children()
135                    .enumerate()
136                    .map(
137                        |(off, v)| (off + 3, v), // add 3 to skip 0 and the two dots
138                    )
139                    .map(|(offset, (name, inode))| {
140                        DirEntry::builder()
141                            .name(name.clone())
142                            .offset(offset as u64)
143                            .inode(inode)
144                            .typ(self.inodes.get(inode).unwrap().file_type())
145                            .build()
146                    }),
147            )
148            .skip(offset as usize)
149            .collect())
150    }
151
152    fn read(&mut self, ino: INode, offset: u64, size: u32) -> Result<&[u8]> {
153        let file = self.inodes.get(ino).ok_or(FSError::NoEntry)?;
154        let file = file.as_file().ok_or(FSError::NotFile)?;
155
156        let offset = offset as usize;
157        let size = size as usize;
158
159        let content = file.data.get(offset..).unwrap_or(&[]);
160        let content = &content[..std::cmp::min(file.size(), size)];
161
162        Ok(content)
163    }
164
165    fn write<T: BufRead>(&mut self, ino: INode, offset: u64, size: u32, mut buf: T) -> Result<u32> {
166        let file = self.inodes.get_mut(ino).ok_or(FSError::NoEntry)?;
167        let file = file.as_file_mut().ok_or(FSError::NotFile)?;
168
169        let offset = offset as usize;
170        let size = size as usize;
171
172        file.data
173            .resize(std::cmp::max(file.size(), offset + size), 0);
174
175        buf.read_exact(&mut file.data[offset..offset + size])
176            .unwrap();
177
178        file.attrs.set_size((offset + size) as u64);
179
180        Ok(size as u32)
181    }
182
183    fn setattr(&mut self, ino: INode, attrs: SetFileAttributes) -> Result<FileAttributes> {
184        let entry = self.inodes.get_mut(ino).ok_or(FSError::NoEntry)?;
185
186        match entry.kind_mut() {
187            INodeKind::Directory(dir) => dir.apply_attrs(attrs),
188            INodeKind::File(file) => file.attrs.apply_attrs(attrs),
189        };
190
191        Ok(entry.getattrs())
192    }
193}
memfs/memfs.rs

memfs/
memfs.rs
