move wasi-c2 into wasi-common
This commit is contained in:
Pat Hickey
306
crates/wasi-common/src/pipe.rs
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306
crates/wasi-common/src/pipe.rs
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// This is mostly stubs
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#![allow(unused_variables, dead_code)]
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//! Virtual pipes.
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//!
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//! These types provide easy implementations of `WasiFile` that mimic much of the behavior of Unix
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//! pipes. These are particularly helpful for redirecting WASI stdio handles to destinations other
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//! than OS files.
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//!
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//! Some convenience constructors are included for common backing types like `Vec<u8>` and `String`,
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//! but the virtual pipes can be instantiated with any `Read` or `Write` type.
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//!
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use crate::{
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file::{FdFlags, FileType, Filestat, WasiFile},
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Error, ErrorExt, SystemTimeSpec,
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};
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use std::any::Any;
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use std::convert::TryInto;
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use std::io::{self, Read, Write};
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use std::sync::{Arc, RwLock};
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use system_interface::fs::Advice;
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/// A virtual pipe read end.
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///
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/// A variety of `From` impls are provided so that common pipe types are easy to create. For example:
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///
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/// ```
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/// # use wasi_c2::WasiCtx;
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/// # use wasi_c2::virt::pipe::ReadPipe;
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/// let stdin = ReadPipe::from("hello from stdin!");
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/// let ctx = WasiCtx::builder().stdin(Box::new(stdin)).build();
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/// ```
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#[derive(Debug)]
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pub struct ReadPipe<R: Read> {
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reader: Arc<RwLock<R>>,
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}
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impl<R: Read> Clone for ReadPipe<R> {
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fn clone(&self) -> Self {
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Self {
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reader: self.reader.clone(),
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}
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}
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}
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impl<R: Read> ReadPipe<R> {
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/// Create a new pipe from a `Read` type.
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///
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/// All `Handle` read operations delegate to reading from this underlying reader.
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pub fn new(r: R) -> Self {
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Self::from_shared(Arc::new(RwLock::new(r)))
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}
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/// Create a new pipe from a shareable `Read` type.
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///
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/// All `Handle` read operations delegate to reading from this underlying reader.
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pub fn from_shared(reader: Arc<RwLock<R>>) -> Self {
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Self { reader }
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}
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/// Try to convert this `ReadPipe<R>` back to the underlying `R` type.
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///
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/// This will fail with `Err(self)` if multiple references to the underlying `R` exist.
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pub fn try_into_inner(mut self) -> Result<R, Self> {
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match Arc::try_unwrap(self.reader) {
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Ok(rc) => Ok(RwLock::into_inner(rc).unwrap()),
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Err(reader) => {
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self.reader = reader;
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Err(self)
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}
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}
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}
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fn borrow(&self) -> std::sync::RwLockWriteGuard<R> {
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RwLock::write(&self.reader).unwrap()
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}
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}
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impl From<Vec<u8>> for ReadPipe<io::Cursor<Vec<u8>>> {
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fn from(r: Vec<u8>) -> Self {
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Self::new(io::Cursor::new(r))
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}
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}
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impl From<&[u8]> for ReadPipe<io::Cursor<Vec<u8>>> {
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fn from(r: &[u8]) -> Self {
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Self::from(r.to_vec())
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}
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}
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impl From<String> for ReadPipe<io::Cursor<String>> {
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fn from(r: String) -> Self {
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Self::new(io::Cursor::new(r))
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}
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}
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impl From<&str> for ReadPipe<io::Cursor<String>> {
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fn from(r: &str) -> Self {
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Self::from(r.to_string())
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}
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}
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impl<R: Read + Any> WasiFile for ReadPipe<R> {
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fn as_any(&self) -> &dyn Any {
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self
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}
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fn datasync(&self) -> Result<(), Error> {
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Ok(()) // trivial: no implementation needed
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}
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fn sync(&self) -> Result<(), Error> {
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Ok(()) // trivial
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}
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fn get_filetype(&self) -> Result<FileType, Error> {
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Ok(FileType::Pipe)
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}
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fn get_fdflags(&self) -> Result<FdFlags, Error> {
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Ok(FdFlags::empty())
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}
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fn set_fdflags(&mut self, _fdflags: FdFlags) -> Result<(), Error> {
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Err(Error::badf())
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}
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fn get_filestat(&self) -> Result<Filestat, Error> {
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Ok(Filestat {
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device_id: 0,
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inode: 0,
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filetype: self.get_filetype()?,
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nlink: 0,
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size: 0, // XXX no way to get a size out of a Read :(
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atim: None,
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mtim: None,
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ctim: None,
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})
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}
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fn set_filestat_size(&self, _size: u64) -> Result<(), Error> {
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Err(Error::badf())
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}
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fn advise(&self, offset: u64, len: u64, advice: Advice) -> Result<(), Error> {
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Err(Error::badf())
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}
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fn allocate(&self, offset: u64, len: u64) -> Result<(), Error> {
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Err(Error::badf())
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}
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fn read_vectored(&self, bufs: &mut [io::IoSliceMut]) -> Result<u64, Error> {
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let n = self.borrow().read_vectored(bufs)?;
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Ok(n.try_into()?)
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}
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fn read_vectored_at(&self, bufs: &mut [io::IoSliceMut], offset: u64) -> Result<u64, Error> {
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Err(Error::badf())
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}
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fn write_vectored(&self, bufs: &[io::IoSlice]) -> Result<u64, Error> {
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Err(Error::badf())
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}
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fn write_vectored_at(&self, bufs: &[io::IoSlice], offset: u64) -> Result<u64, Error> {
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Err(Error::badf())
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}
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fn seek(&self, pos: std::io::SeekFrom) -> Result<u64, Error> {
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Err(Error::badf())
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}
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fn peek(&self, buf: &mut [u8]) -> Result<u64, Error> {
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Err(Error::badf())
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}
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fn set_times(
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&self,
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atime: Option<SystemTimeSpec>,
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mtime: Option<SystemTimeSpec>,
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) -> Result<(), Error> {
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Err(Error::badf())
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}
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fn num_ready_bytes(&self) -> Result<u64, Error> {
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Ok(0)
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}
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}
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/// A virtual pipe write end.
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///
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/// ```
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/// # use wasi_c2::WasiCtx;
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/// # use wasi_c2::virt::pipe::WritePipe;
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/// let stdout = WritePipe::new_in_memory();
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/// let ctx = WasiCtx::builder().stdout(Box::new(stdout.clone())).build();
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/// // use ctx in an instance, then make sure it is dropped:
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/// drop(ctx);
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/// let contents: Vec<u8> = stdout.try_into_inner().expect("sole remaining reference to WritePipe").into_inner();
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/// println!("contents of stdout: {:?}", contents);
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/// ```
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#[derive(Debug)]
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pub struct WritePipe<W: Write> {
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writer: Arc<RwLock<W>>,
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}
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impl<W: Write> Clone for WritePipe<W> {
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fn clone(&self) -> Self {
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Self {
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writer: self.writer.clone(),
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}
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}
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}
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impl<W: Write> WritePipe<W> {
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/// Create a new pipe from a `Write` type.
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///
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/// All `Handle` write operations delegate to writing to this underlying writer.
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pub fn new(w: W) -> Self {
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Self::from_shared(Arc::new(RwLock::new(w)))
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}
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/// Create a new pipe from a shareable `Write` type.
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///
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/// All `Handle` write operations delegate to writing to this underlying writer.
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pub fn from_shared(writer: Arc<RwLock<W>>) -> Self {
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Self { writer }
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}
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/// Try to convert this `WritePipe<W>` back to the underlying `W` type.
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///
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/// This will fail with `Err(self)` if multiple references to the underlying `W` exist.
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pub fn try_into_inner(mut self) -> Result<W, Self> {
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match Arc::try_unwrap(self.writer) {
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Ok(rc) => Ok(RwLock::into_inner(rc).unwrap()),
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Err(writer) => {
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self.writer = writer;
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Err(self)
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}
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}
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}
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fn borrow(&self) -> std::sync::RwLockWriteGuard<W> {
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RwLock::write(&self.writer).unwrap()
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}
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}
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impl WritePipe<io::Cursor<Vec<u8>>> {
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/// Create a new writable virtual pipe backed by a `Vec<u8>` buffer.
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pub fn new_in_memory() -> Self {
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Self::new(io::Cursor::new(vec![]))
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}
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}
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impl<W: Write + Any> WasiFile for WritePipe<W> {
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fn as_any(&self) -> &dyn Any {
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self
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}
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fn datasync(&self) -> Result<(), Error> {
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Ok(())
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}
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fn sync(&self) -> Result<(), Error> {
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Ok(())
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}
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fn get_filetype(&self) -> Result<FileType, Error> {
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Ok(FileType::Pipe)
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}
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fn get_fdflags(&self) -> Result<FdFlags, Error> {
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Ok(FdFlags::APPEND)
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}
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fn set_fdflags(&mut self, _fdflags: FdFlags) -> Result<(), Error> {
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Err(Error::badf())
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}
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fn get_filestat(&self) -> Result<Filestat, Error> {
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Ok(Filestat {
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device_id: 0,
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inode: 0,
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filetype: self.get_filetype()?,
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nlink: 0,
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size: 0, // XXX no way to get a size out of a Write :(
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atim: None,
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mtim: None,
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ctim: None,
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})
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}
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fn set_filestat_size(&self, _size: u64) -> Result<(), Error> {
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Err(Error::badf())
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}
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fn advise(&self, offset: u64, len: u64, advice: Advice) -> Result<(), Error> {
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Err(Error::badf())
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}
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fn allocate(&self, offset: u64, len: u64) -> Result<(), Error> {
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Err(Error::badf())
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}
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fn read_vectored(&self, bufs: &mut [io::IoSliceMut]) -> Result<u64, Error> {
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Err(Error::badf())
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}
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fn read_vectored_at(&self, bufs: &mut [io::IoSliceMut], offset: u64) -> Result<u64, Error> {
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Err(Error::badf())
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}
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fn write_vectored(&self, bufs: &[io::IoSlice]) -> Result<u64, Error> {
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let n = self.borrow().write_vectored(bufs)?;
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Ok(n.try_into()?)
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}
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fn write_vectored_at(&self, bufs: &[io::IoSlice], offset: u64) -> Result<u64, Error> {
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Err(Error::badf())
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}
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fn seek(&self, pos: std::io::SeekFrom) -> Result<u64, Error> {
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Err(Error::badf())
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}
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fn peek(&self, buf: &mut [u8]) -> Result<u64, Error> {
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Err(Error::badf())
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}
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fn set_times(
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&self,
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atime: Option<SystemTimeSpec>,
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mtime: Option<SystemTimeSpec>,
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) -> Result<(), Error> {
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Err(Error::badf())
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}
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fn num_ready_bytes(&self) -> Result<u64, Error> {
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Ok(0)
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}
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}
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