89 lines
2.1 KiB
Rust
89 lines
2.1 KiB
Rust
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use collections::BTreeMap;
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use syscall::{Error, Result};
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use super::Scheme;
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struct Handle {
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data: &'static [u8],
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seek: usize
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}
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pub struct EnvScheme {
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next_id: usize,
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files: BTreeMap<&'static [u8], &'static [u8]>,
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handles: BTreeMap<usize, Handle>
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}
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impl EnvScheme {
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pub fn new() -> EnvScheme {
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let mut files: BTreeMap<&'static [u8], &'static [u8]> = BTreeMap::new();
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files.insert(b"HOME", b"initfs:");
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files.insert(b"PWD", b"initfs:");
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files.insert(b"COLUMNS", b"80");
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files.insert(b"LINES", b"30");
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EnvScheme {
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next_id: 0,
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files: files,
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handles: BTreeMap::new()
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}
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}
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}
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impl Scheme for EnvScheme {
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fn open(&mut self, path: &[u8], _flags: usize) -> Result<usize> {
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let data = self.files.get(path).ok_or(Error::NoEntry)?;
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let id = self.next_id;
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self.next_id += 1;
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self.handles.insert(id, Handle {
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data: data,
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seek: 0
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});
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Ok(id)
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}
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fn dup(&mut self, file: usize) -> Result<usize> {
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let (data, seek) = {
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let handle = self.handles.get(&file).ok_or(Error::BadFile)?;
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(handle.data, handle.seek)
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};
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let id = self.next_id;
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self.next_id += 1;
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self.handles.insert(id, Handle {
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data: data,
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seek: seek
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});
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Ok(id)
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}
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fn read(&mut self, file: usize, buffer: &mut [u8]) -> Result<usize> {
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let mut handle = self.handles.get_mut(&file).ok_or(Error::BadFile)?;
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let mut i = 0;
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while i < buffer.len() && handle.seek < handle.data.len() {
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buffer[i] = handle.data[handle.seek];
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i += 1;
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handle.seek += 1;
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}
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Ok(i)
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}
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fn write(&mut self, _file: usize, _buffer: &[u8]) -> Result<usize> {
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Err(Error::NotPermitted)
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}
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fn fsync(&mut self, file: usize) -> Result<()> {
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Ok(())
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}
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fn close(&mut self, file: usize) -> Result<()> {
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self.handles.remove(&file).ok_or(Error::BadFile).and(Ok(()))
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}
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}
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