refactor: simplify FileLike with downcast-rs

Author: AsakuraMizu

Cargo.lock

@@ -37,6 +37,7 @@ bitmaps = { version = "3.2.1", default-features = false }
 bytemuck.workspace = true
 cfg-if.workspace = true
 chrono = { version = "0.4.41", default-features = false }
+downcast-rs = { version = "2.0", default-features = false, features = ["sync"] }
 event-listener.workspace = true
 flatten_objects = "0.2.4"
 gimli = { version = "*", default-features = false, optional = true }

api/Cargo.toml

@@ -13,7 +13,6 @@ use alloc::{
     task::Wake,
 };
 use core::{
-    any::Any,
     hash::{Hash, Hasher},
     sync::atomic::{AtomicBool, Ordering},
     task::{Context, Waker},
@@ -437,10 +436,6 @@ impl FileLike for Epoll {
     fn path(&self) -> Cow<'_, str> {
         "anon_inode:[eventpoll]".into()
     }
-
-    fn into_any(self: Arc<Self>) -> Arc<dyn Any + Send + Sync> {
-        self
-    }
 }
 
 impl Pollable for Epoll {

api/src/file/epoll.rs

@@ -1,6 +1,5 @@
 use alloc::{borrow::Cow, sync::Arc};
 use core::{
-    any::Any,
     sync::atomic::{AtomicBool, AtomicU64, Ordering},
     task::Context,
 };
@@ -105,10 +104,6 @@ impl FileLike for EventFd {
     fn path(&self) -> Cow<'_, str> {
         "anon_inode:[eventfd]".into()
     }
-
-    fn into_any(self: Arc<Self>) -> Arc<dyn Any + Send + Sync> {
-        self
-    }
 }
 
 impl Pollable for EventFd {

api/src/file/event.rs

@@ -1,6 +1,5 @@
 use alloc::{borrow::Cow, string::ToString, sync::Arc};
 use core::{
-    any::Any,
     ffi::c_int,
     hint::likely,
     sync::atomic::{AtomicBool, Ordering},
@@ -56,7 +55,7 @@ pub fn resolve_at(dirfd: c_int, path: Option<&str>, flags: u32) -> AxResult<Reso
                 return Err(AxError::NotFound);
             }
             let file_like = get_file_like(dirfd)?;
-            let f = file_like.clone().into_any();
+            let f = file_like.clone();
             Ok(if let Some(file) = f.downcast_ref::<File>() {
                 ResolveAtResult::File(file.inner().backend()?.location().clone())
             } else if let Some(dir) = f.downcast_ref::<Directory>() {
@@ -152,10 +151,6 @@ impl FileLike for File {
         Ok(metadata_to_kstat(&self.inner().location().metadata()?))
     }
 
-    fn into_any(self: Arc<Self>) -> Arc<dyn Any + Send + Sync> {
-        self
-    }
-
     fn ioctl(&self, cmd: u32, arg: usize) -> AxResult<usize> {
         self.inner().backend()?.location().ioctl(cmd, arg)
     }
@@ -177,9 +172,7 @@ impl FileLike for File {
     where
         Self: Sized + 'static,
     {
-        let any = get_file_like(fd)?.into_any();
-
-        any.downcast::<Self>().map_err(|any| {
+        get_file_like(fd)?.downcast_arc().map_err(|any| {
             if any.is::<Directory>() {
                 AxError::IsADirectory
             } else {
@@ -235,14 +228,9 @@ impl FileLike for Directory {
         path_for(&self.inner)
     }
 
-    fn into_any(self: Arc<Self>) -> Arc<dyn Any + Send + Sync> {
-        self
-    }
-
     fn from_fd(fd: c_int) -> AxResult<Arc<Self>> {
         get_file_like(fd)?
-            .into_any()
-            .downcast::<Self>()
+            .downcast_arc()
             .map_err(|_| AxError::NotADirectory)
     }
 }

api/src/file/fs.rs

@@ -7,14 +7,15 @@ mod pipe;
 pub mod signalfd;
 
 use alloc::{borrow::Cow, sync::Arc};
-use core::{any::Any, ffi::c_int, time::Duration};
+use core::{ffi::c_int, time::Duration};
 
 use axerrno::{AxError, AxResult};
 use axfs::{FS_CONTEXT, OpenOptions};
 use axfs_ng_vfs::DeviceId;
 use axio::prelude::*;
 use axpoll::Pollable;
 use axtask::current;
+use downcast_rs::{DowncastSync, impl_downcast};
 use flatten_objects::FlattenObjects;
 use linux_raw_sys::general::{RLIMIT_NOFILE, stat, statx, statx_timestamp};
 use spin::RwLock;
@@ -133,7 +134,7 @@ impl<T: Read + IoBuf> ReadBuf for T {}
 pub type IoSrc<'a> = dyn ReadBuf + 'a;
 
 #[allow(dead_code)]
-pub trait FileLike: Pollable + Send + Sync {
+pub trait FileLike: Pollable + DowncastSync {
     fn read(&self, _dst: &mut IoDst) -> AxResult<usize> {
         Err(AxError::InvalidInput)
     }
@@ -146,8 +147,6 @@ pub trait FileLike: Pollable + Send + Sync {
         Ok(Kstat::default())
     }
 
-    fn into_any(self: Arc<Self>) -> Arc<dyn Any + Send + Sync>;
-
     fn path(&self) -> Cow<'_, str>;
 
     fn ioctl(&self, _cmd: u32, _arg: usize) -> AxResult<usize> {
@@ -167,8 +166,7 @@ pub trait FileLike: Pollable + Send + Sync {
         Self: Sized + 'static,
     {
         get_file_like(fd)?
-            .into_any()
-            .downcast::<Self>()
+            .downcast_arc()
             .map_err(|_| AxError::InvalidInput)
     }
 
@@ -179,6 +177,7 @@ pub trait FileLike: Pollable + Send + Sync {
         add_file_like(Arc::new(self), cloexec)
     }
 }
+impl_downcast!(sync FileLike);
 
 #[derive(Clone)]
 pub struct FileDescriptor {

api/src/file/mod.rs

@@ -40,10 +40,6 @@ impl FileLike for Socket {
         })
     }
 
-    fn into_any(self: Arc<Self>) -> Arc<dyn core::any::Any + Send + Sync> {
-        self
-    }
-
     fn nonblocking(&self) -> bool {
         let mut result = false;
         self.get_option(GetSocketOption::NonBlocking(&mut result))
@@ -65,8 +61,7 @@ impl FileLike for Socket {
         Self: Sized + 'static,
     {
         get_file_like(fd)?
-            .into_any()
-            .downcast::<Self>()
+            .downcast_arc()
             .map_err(|_| AxError::NotASocket)
     }
 }

api/src/file/net.rs

@@ -30,10 +30,6 @@ impl FileLike for PidFd {
     fn path(&self) -> Cow<'_, str> {
         "anon_inode:[pidfd]".into()
     }
-
-    fn into_any(self: Arc<Self>) -> Arc<dyn core::any::Any + Send + Sync> {
-        self
-    }
 }
 
 impl Pollable for PidFd {

api/src/file/pidfd.rs

@@ -1,6 +1,5 @@
 use alloc::{borrow::Cow, format, sync::Arc};
 use core::{
-    any::Any,
     mem,
     sync::atomic::{AtomicBool, Ordering},
     task::Context,
@@ -190,10 +189,6 @@ impl FileLike for Pipe {
         format!("pipe:[{}]", self as *const _ as usize).into()
     }
 
-    fn into_any(self: Arc<Self>) -> Arc<dyn Any + Send + Sync> {
-        self
-    }
-
     fn set_nonblocking(&self, nonblocking: bool) -> AxResult {
         self.non_blocking.store(nonblocking, Ordering::Release);
         Ok(())

api/src/file/pipe.rs

@@ -1,6 +1,5 @@
 use alloc::{borrow::Cow, sync::Arc};
 use core::{
-    any::Any,
     mem,
     sync::atomic::{AtomicBool, Ordering},
     task::Context,
@@ -164,10 +163,6 @@ impl FileLike for Signalfd {
     fn path(&self) -> Cow<'_, str> {
         "anon_inode:[signalfd]".into()
     }
-
-    fn into_any(self: Arc<Self>) -> Arc<dyn Any + Send + Sync> {
-        self
-    }
 }
 
 impl Pollable for Signalfd {