1 files changed, 379 insertions, 0 deletions
diff --git a/src/io.rs b/src/io.rs
new file mode 100644
index 0000000..7124fda
--- /dev/null
+++ b/src/io.rs
@@ -0,0 +1,379 @@
+use bytemuck::Zeroable;
+use nix::{errno::Errno, sys::stat::SFlag};
+
+use std::{
+    convert::Infallible,
+    ffi::OsStr,
+    future::Future,
+    ops::{ControlFlow, FromResidual, Try},
+};
+
+use super::{Done, Operation, Reply, Request};
+use crate::{proto, FuseResult, Ino, Timestamp, Ttl};
+
+#[doc(no_inline)]
+pub use nix::{
+    dir::Type as EntryType,
+    fcntl::OFlag as OpenFlags,
+    sys::stat::Mode,
+    unistd::{AccessFlags, Gid, Pid, Uid},
+};
+
+pub enum Interruptible<'o, O: Operation<'o>, T> {
+    Completed(Reply<'o, O>, T),
+    Interrupted(Done<'o>),
+}
+
+pub trait Stat {
+    fn ino(&self) -> Ino;
+    fn inode_type(&self) -> EntryType;
+    fn attrs(&self) -> (Attrs, Ttl);
+}
+
+pub trait Known {
+    type Inode: Stat;
+
+    fn inode(&self) -> &Self::Inode;
+    fn unveil(self);
+}
+
+pub struct Failed<'o, E>(pub Done<'o>, pub E);
+
+pub trait Finish<'o, O: Operation<'o>> {
+    fn finish(&self, reply: Reply<'o, O>) -> Done<'o>;
+}
+
+#[derive(Clone)]
+pub struct Attrs(proto::Attrs);
+
+pub struct Entry<'a, K> {
+    pub offset: u64,
+    pub name: &'a OsStr,
+    pub inode: K,
+    pub ttl: Ttl,
+}
+
+#[derive(Copy, Clone)]
+pub struct FsInfo(proto::StatfsOut);
+
+impl<'o, E> From<Failed<'o, E>> for Done<'o> {
+    fn from(failed: Failed<'o, E>) -> Done<'o> {
+        failed.0
+    }
+}
+
+impl<'o, O: Operation<'o>> Finish<'o, O> for Errno {
+    fn finish(&self, reply: Reply<'o, O>) -> Done<'o> {
+        reply.fail(*self)
+    }
+}
+
+impl<'o, O: Operation<'o>> Finish<'o, O> for std::io::Error {
+    fn finish(&self, reply: Reply<'o, O>) -> Done<'o> {
+        reply.fail(
+            self.raw_os_error()
+                .map(Errno::from_i32)
+                .unwrap_or(Errno::EIO),
+        )
+    }
+}
+
+impl<'o, O: Operation<'o>> Request<'o, O> {
+    pub fn ino(&self) -> Ino {
+        Ino(self.header.ino)
+    }
+
+    pub fn generation(&self) -> u64 {
+        0
+    }
+
+    pub fn uid(&self) -> Uid {
+        Uid::from_raw(self.header.uid)
+    }
+
+    pub fn gid(&self) -> Gid {
+        Gid::from_raw(self.header.gid)
+    }
+
+    pub fn pid(&self) -> Pid {
+        Pid::from_raw(self.header.pid as i32)
+    }
+}
+
+impl<'o, O: Operation<'o>> Reply<'o, O> {
+    pub async fn interruptible<F, T>(self, f: F) -> Interruptible<'o, O, T>
+    where
+        F: Future<Output = T>,
+    {
+        tokio::pin!(f);
+        let mut rx = self.session.interrupt_rx();
+
+        use Interruptible::*;
+        loop {
+            tokio::select! {
+                output = &mut f => break Completed(self, output),
+
+                result = rx.recv() => match result {
+                    Ok(unique) if unique == self.unique => {
+                        break Interrupted(self.interrupted());
+                    }
+
+                    _ => continue,
+                }
+            }
+        }
+    }
+
+    pub fn and_then<T, E>(self, result: Result<T, E>) -> Result<(Self, T), Failed<'o, E>>
+    where
+        E: Finish<'o, O>,
+    {
+        match result {
+            Ok(t) => Ok((self, t)),
+            Err(error) => {
+                let done = error.finish(self);
+                Err(Failed(done, error))
+            }
+        }
+    }
+
+    pub fn fail(self, errno: Errno) -> Done<'o> {
+        let result = self.session.fail(self.unique, errno as i32);
+        self.finish(result)
+    }
+
+    pub fn not_implemented(self) -> Done<'o> {
+        self.fail(Errno::ENOSYS)
+    }
+
+    pub fn not_permitted(self) -> Done<'o> {
+        self.fail(Errno::EPERM)
+    }
+
+    pub fn io_error(self) -> Done<'o> {
+        self.fail(Errno::EIO)
+    }
+
+    pub fn invalid_argument(self) -> Done<'o> {
+        self.fail(Errno::EINVAL)
+    }
+
+    pub fn interrupted(self) -> Done<'o> {
+        self.fail(Errno::EINTR)
+    }
+
+    pub(crate) fn finish(self, result: FuseResult<()>) -> Done<'o> {
+        if let Err(error) = result {
+            log::error!("Replying to request {}: {}", self.unique, error);
+        }
+
+        Done::new()
+    }
+}
+
+impl<'o, O: Operation<'o>> From<(Reply<'o, O>, Errno)> for Done<'o> {
+    fn from((reply, errno): (Reply<'o, O>, Errno)) -> Done<'o> {
+        reply.fail(errno)
+    }
+}
+
+impl<'o> FromResidual<Done<'o>> for Done<'o> {
+    fn from_residual(residual: Done<'o>) -> Self {
+        residual
+    }
+}
+
+impl<'o, T: Into<Done<'o>>> FromResidual<Result<Infallible, T>> for Done<'o> {
+    fn from_residual(residual: Result<Infallible, T>) -> Self {
+        match residual {
+            Ok(_) => unreachable!(),
+            Err(t) => t.into(),
+        }
+    }
+}
+
+impl<'o, O: Operation<'o>> FromResidual<Interruptible<'o, O, Infallible>> for Done<'o> {
+    fn from_residual(residual: Interruptible<'o, O, Infallible>) -> Self {
+        match residual {
+            Interruptible::Completed(_, _) => unreachable!(),
+            Interruptible::Interrupted(done) => done,
+        }
+    }
+}
+
+impl Try for Done<'_> {
+    type Output = Self;
+    type Residual = Self;
+
+    fn from_output(output: Self::Output) -> Self {
+        output
+    }
+
+    fn branch(self) -> ControlFlow<Self::Residual, Self::Output> {
+        ControlFlow::Break(self)
+    }
+}
+
+impl<'o, O: Operation<'o>, T> FromResidual<Interruptible<'o, O, Infallible>>
+    for Interruptible<'o, O, T>
+{
+    fn from_residual(residual: Interruptible<'o, O, Infallible>) -> Self {
+        use Interruptible::*;
+
+        match residual {
+            Completed(_, _) => unreachable!(),
+            Interrupted(done) => Interrupted(done),
+        }
+    }
+}
+
+impl<'o, O: Operation<'o>, T> Try for Interruptible<'o, O, T> {
+    type Output = (Reply<'o, O>, T);
+    type Residual = Interruptible<'o, O, Infallible>;
+
+    fn from_output((reply, t): Self::Output) -> Self {
+        Self::Completed(reply, t)
+    }
+
+    fn branch(self) -> ControlFlow<Self::Residual, Self::Output> {
+        use Interruptible::*;
+
+        match self {
+            Completed(reply, t) => ControlFlow::Continue((reply, t)),
+            Interrupted(done) => ControlFlow::Break(Interrupted(done)),
+        }
+    }
+}
+
+impl Attrs {
+    #[must_use]
+    pub fn size(self, size: u64) -> Self {
+        Attrs(proto::Attrs { size, ..self.0 })
+    }
+
+    #[must_use]
+    pub fn owner(self, uid: Uid, gid: Gid) -> Self {
+        Attrs(proto::Attrs {
+            uid: uid.as_raw(),
+            gid: gid.as_raw(),
+            ..self.0
+        })
+    }
+
+    #[must_use]
+    pub fn mode(self, mode: Mode) -> Self {
+        Attrs(proto::Attrs {
+            mode: mode.bits(),
+            ..self.0
+        })
+    }
+
+    #[must_use]
+    pub fn blocks(self, blocks: u64) -> Self {
+        Attrs(proto::Attrs { blocks, ..self.0 })
+    }
+
+    #[must_use]
+    pub fn block_size(self, block_size: u32) -> Self {
+        Attrs(proto::Attrs {
+            blksize: block_size,
+            ..self.0
+        })
+    }
+
+    #[must_use]
+    pub fn device(self, device: u32) -> Self {
+        Attrs(proto::Attrs {
+            rdev: device,
+            ..self.0
+        })
+    }
+
+    #[must_use]
+    pub fn times(self, access: Timestamp, modify: Timestamp, change: Timestamp) -> Self {
+        Attrs(proto::Attrs {
+            atime: access.seconds as _,
+            mtime: modify.seconds as _,
+            ctime: change.seconds as _,
+            atimensec: access.nanoseconds,
+            mtimensec: modify.nanoseconds,
+            ctimensec: change.nanoseconds,
+            ..self.0
+        })
+    }
+
+    #[must_use]
+    pub fn links(self, links: u32) -> Self {
+        Attrs(proto::Attrs {
+            nlink: links,
+            ..self.0
+        })
+    }
+
+    pub(crate) fn finish(self, inode: &impl Stat) -> proto::Attrs {
+        let Ino(ino) = inode.ino();
+        let inode_type = match inode.inode_type() {
+            EntryType::Fifo => SFlag::S_IFIFO,
+            EntryType::CharacterDevice => SFlag::S_IFCHR,
+            EntryType::Directory => SFlag::S_IFDIR,
+            EntryType::BlockDevice => SFlag::S_IFBLK,
+            EntryType::File => SFlag::S_IFREG,
+            EntryType::Symlink => SFlag::S_IFLNK,
+            EntryType::Socket => SFlag::S_IFSOCK,
+        };
+
+        proto::Attrs {
+            ino,
+            mode: self.0.mode | inode_type.bits(),
+            ..self.0
+        }
+    }
+}
+
+impl Default for Attrs {
+    fn default() -> Self {
+        Attrs(Zeroable::zeroed()).links(1)
+    }
+}
+
+impl FsInfo {
+    #[must_use]
+    pub fn blocks(self, size: u32, total: u64, free: u64, available: u64) -> Self {
+        FsInfo(proto::StatfsOut {
+            bsize: size,
+            blocks: total,
+            bfree: free,
+            bavail: available,
+            ..self.0
+        })
+    }
+
+    #[must_use]
+    pub fn inodes(self, total: u64, free: u64) -> Self {
+        FsInfo(proto::StatfsOut {
+            files: total,
+            ffree: free,
+            ..self.0
+        })
+    }
+
+    #[must_use]
+    pub fn max_filename(self, max: u32) -> Self {
+        FsInfo(proto::StatfsOut {
+            namelen: max,
+            ..self.0
+        })
+    }
+}
+
+impl Default for FsInfo {
+    fn default() -> Self {
+        FsInfo(Zeroable::zeroed())
+    }
+}
+
+impl From<FsInfo> for proto::StatfsOut {
+    fn from(FsInfo(statfs): FsInfo) -> proto::StatfsOut {
+        statfs
+    }
+}