docs: add some doc

Signed-off-by: lzzzt <liuzitao0123@gmail.com>

.github/workflows/ci.sh

@@ -27,8 +27,8 @@ if [ "${NO_RUN}" != "1" ] && [ "${NO_RUN}" != "true" ]; then
     "${CARGO}" test --target "${TARGET}" --no-default-features --features "async-cancel,bytes,legacy,macros,utils" --release
 
     # enable legacy and sync
-    "${CARGO}" test --target "${TARGET}" --no-default-features --features "async-cancel,bytes,legacy,macros,utils,asyncify-op"
-    "${CARGO}" test --target "${TARGET}" --no-default-features --features "async-cancel,bytes,legacy,macros,utils,asyncify-op" --release
+    "${CARGO}" test --target "${TARGET}" --no-default-features --features "async-cancel,bytes,legacy,macros,utils,sync"
+    "${CARGO}" test --target "${TARGET}" --no-default-features --features "async-cancel,bytes,legacy,macros,utils,sync" --release
 
     if [ "${TARGET}" = "x86_64-unknown-linux-gnu" ] || [ "${TARGET}" = "i686-unknown-linux-gnu" ]; then
         # only enabled uring driver

monoio/Cargo.toml

@@ -96,8 +96,6 @@ poll-io = ["tokio", "mio"]
 # signal enables setting ctrl_c handler
 signal = ["ctrlc", "sync"]
 signal-termination = ["signal", "ctrlc/termination"]
-# asyncify-op will run fs related task in blocking_thread_pool
-asyncify-op = ["sync", "legacy"]
 # by default both iouring and legacy are enabled
 default = ["async-cancel", "bytes", "iouring", "legacy", "macros", "utils"]
 

monoio/src/builder.rs

@@ -32,15 +32,29 @@ pub struct RuntimeBuilder<D> {
 scoped_thread_local!(pub(crate) static BUILD_THREAD_ID: usize);
 
 impl<T> Default for RuntimeBuilder<T> {
-    /// Create a default runtime builder
+    /// Create a default runtime builder.
+    ///
+    /// # Note
+    ///
+    /// When the sync feature is enabled, the default behavior of
+    /// [monoio::blocking::BlockingStrategy] is to execute tasks on the local thread. In other
+    /// words, there is no thread pool involved—all blocking I/O operations and heavy computations
+    /// will block the current thread.
     #[must_use]
     fn default() -> Self {
         RuntimeBuilder::<T>::new()
     }
 }
 
 impl<T> RuntimeBuilder<T> {
-    /// Create a default runtime builder
+    /// Create a default runtime builder.
+    ///
+    /// # Note
+    ///
+    /// When the sync feature is enabled, the default behavior of
+    /// [monoio::blocking::BlockingStrategy] is to execute tasks on the local thread. In other
+    /// words, there is no thread pool involved—all blocking I/O operations and heavy computations
+    /// will block the current thread.
     #[must_use]
     pub fn new() -> Self {
         Self {
@@ -50,7 +64,7 @@ impl<T> RuntimeBuilder<T> {
             urb: io_uring::IoUring::builder(),
 
             #[cfg(feature = "sync")]
-            blocking_handle: crate::blocking::BlockingStrategy::Panic.into(),
+            blocking_handle: crate::blocking::BlockingStrategy::ExecuteLocal.into(),
             _mark: PhantomData,
         }
     }

monoio/src/driver/op/read.rs

@@ -6,11 +6,6 @@ use std::os::unix::prelude::AsRawFd;
 pub(crate) use impls::*;
 #[cfg(all(target_os = "linux", feature = "iouring"))]
 use io_uring::{opcode, types};
-#[cfg(all(windows, any(feature = "legacy", feature = "poll-io")))]
-use {
-    std::ffi::c_void,
-    windows_sys::Win32::{Foundation::TRUE, Storage::FileSystem::ReadFile},
-};
 
 use super::{super::shared_fd::SharedFd, Op, OpAble};
 #[cfg(any(feature = "legacy", feature = "poll-io"))]
@@ -315,21 +310,25 @@ pub(crate) mod impls {
     use super::*;
     use crate::syscall_u32;
 
+    /// A wrapper for [`libc::read`]
     pub(crate) fn read(fd: i32, buf: *mut u8, len: usize) -> io::Result<u32> {
         syscall_u32!(read(fd, buf as _, len))
     }
 
+    /// A wrapper of [`libc::pread`]
     pub(crate) fn read_at(fd: i32, buf: *mut u8, len: usize, offset: u64) -> io::Result<u32> {
         let offset = libc::off_t::try_from(offset)
             .map_err(|_| io::Error::new(io::ErrorKind::Other, "offset too big"))?;
 
         syscall_u32!(pread(fd, buf as _, len, offset))
     }
 
+    /// A wrapper of [`libc::readv`]
     pub(crate) fn read_vectored(fd: i32, buf_vec: *mut iovec, len: usize) -> io::Result<u32> {
         syscall_u32!(readv(fd, buf_vec as _, len as _))
     }
 
+    /// A wrapper of [`libc::preadv`]
     pub(crate) fn read_vectored_at(
         fd: i32,
         buf_vec: *mut iovec,
@@ -345,13 +344,17 @@ pub(crate) mod impls {
 
 #[cfg(all(any(feature = "legacy", feature = "poll-io"), windows))]
 pub(crate) mod impls {
+    use std::ffi::c_void;
+
     use windows_sys::Win32::{
-        Foundation::{GetLastError, ERROR_HANDLE_EOF},
+        Foundation::{GetLastError, ERROR_HANDLE_EOF, TRUE},
+        Storage::FileSystem::ReadFile,
         System::IO::OVERLAPPED,
     };
 
     use super::*;
 
+    /// A wrapper of [`windows_sys::Win32::Storage::FileSystem::ReadFile`]
     pub(crate) fn read(handle: isize, buf: *mut u8, len: usize) -> io::Result<u32> {
         let mut bytes_read = 0;
         let ret = unsafe {
@@ -374,6 +377,8 @@ pub(crate) mod impls {
         }
     }
 
+    /// A wrapper of [`windows_sys::Win32::Storage::FileSystem::ReadFile`] and using the
+    /// [`windows_sys::Win32::System::IO::OVERLAPPED`] to read at specific position.
     pub(crate) fn read_at(handle: isize, buf: *mut u8, len: usize, offset: u64) -> io::Result<u32> {
         let mut bytes_read = 0;
         let ret = unsafe {

monoio/src/fs/file/mod.rs

@@ -162,6 +162,20 @@ impl File {
     ///     - this function will change the file pointer, but the `pos` always start from the begin
     ///       of file.
     ///
+    /// Addtionally,
+    ///
+    /// - On Unix and Windows (without the `iouring` feature enabled or not support the `iouring`):
+    ///     - If the sync feature is enabled and the thread pool is attached, this operation will be
+    ///       executed on the blocking thread pool, preventing it from blocking the current thread.
+    ///     - If the sync feature is enabled but the thread pool is not attached, or if the sync
+    ///       feature is disabled, the operation will be executed on the local thread, blocking the
+    ///       current thread.
+    ///
+    /// - On Linux (with iouring enabled and supported):
+    ///
+    ///     This operation will use io-uring to execute the task asynchronously.
+    ///
+    ///
     /// # Errors
     ///
     /// If this function encounters any form of I/O or other error, an error
@@ -297,6 +311,19 @@ impl File {
     /// underlying file is no longer able to accept bytes and will likely not be
     /// able to in the future as well, or that the buffer provided is empty.
     ///
+    /// # Platform-specific behavior
+    ///
+    /// - On Unix and Windows (without the `iouring` feature enabled or not support the `iouring`):
+    ///     - If the sync feature is enabled and the thread pool is attached, this operation will be
+    ///       executed on the blocking thread pool, preventing it from blocking the current thread.
+    ///     - If the sync feature is enabled but the thread pool is not attached, or if the sync
+    ///       feature is disabled, the operation will be executed on the local thread, blocking the
+    ///       current thread.
+    ///
+    /// - On Linux (with iouring enabled and supported):
+    ///
+    ///     This operation will use io-uring to execute the task asynchronously.
+    ///
     /// # Errors
     ///
     /// Each call to `write` may generate an I/O error indicating that the
@@ -628,6 +655,19 @@ impl AsyncReadRent for File {
     /// It is not an error if `n` is smaller than the buffer size, even if there is enough data in
     /// the file to fill the buffer.
     ///
+    /// # Platform-specific behavior
+    ///
+    /// - On Unix and Windows (without the `iouring` feature enabled or not support the `iouring`):
+    ///     - If the sync feature is enabled and the thread pool is attached, this operation will be
+    ///       executed on the blocking thread pool, preventing it from blocking the current thread.
+    ///     - If the sync feature is enabled but the thread pool is not attached, or if the sync
+    ///       feature is disabled, the operation will be executed on the local thread, blocking the
+    ///       current thread.
+    ///
+    /// - On Linux (with iouring enabled and supported):
+    ///
+    ///     This operation will use io-uring to execute the task asynchronously.
+    ///
     /// # Errors
     ///
     /// If an I/O or other error occurs, an error variant will be returned, and the buffer will also
@@ -675,6 +715,18 @@ impl AsyncReadRent for File {
     ///     - due to windows does not have syscall like `readv`, so the implement of this function
     ///       on windows is by internally calling the `ReadFile` syscall to fill each buffer.
     ///
+    /// - On Unix and Windows (without the `iouring` feature enabled or not support the `iouring`):
+    ///     - If the sync feature is enabled and the thread pool is attached, this operation will be
+    ///       executed on the blocking thread pool, preventing it from blocking the current thread.
+    ///     - If the sync feature is enabled but the thread pool is not attached, or if the sync
+    ///       feature is disabled, the operation will be executed on the local thread, blocking the
+    ///       current thread.
+    ///
+    /// - On Linux (with iouring enabled and supported):
+    ///
+    ///     This operation will use io-uring to execute the task asynchronously.
+    ///
+    ///
     /// # Errors
     ///
     /// If this function encounters any form of I/O or other error, an error

monoio/src/fs/file/unix.rs

@@ -4,10 +4,10 @@ use std::{
     os::fd::{AsRawFd, IntoRawFd, RawFd},
 };
 
-#[cfg(all(feature = "asyncify-op", not(feature = "iouring")))]
+#[cfg(all(not(feature = "iouring"), feature = "sync"))]
 pub(crate) use asyncified::*;
-#[cfg(any(not(feature = "asyncify-op"), feature = "iouring"))]
-pub(crate) use uring_or_blocking::*;
+#[cfg(any(feature = "iouring", not(feature = "sync")))]
+pub(crate) use iouring::*;
 
 use super::File;
 use crate::{
@@ -77,8 +77,8 @@ pub(crate) async fn metadata(fd: SharedFd) -> std::io::Result<Metadata> {
     op.result().await.map(FileAttr::from).map(Metadata)
 }
 
-#[cfg(any(not(feature = "asyncify-op"), feature = "iouring"))]
-mod uring_or_blocking {
+#[cfg(any(feature = "iouring", not(feature = "sync")))]
+mod iouring {
     use super::*;
 
     pub(crate) async fn read<T: IoBufMut>(fd: SharedFd, buf: T) -> crate::BufResult<usize, T> {
@@ -104,7 +104,7 @@ mod uring_or_blocking {
     }
 }
 
-#[cfg(all(feature = "asyncify-op", not(feature = "iouring")))]
+#[cfg(all(not(feature = "iouring"), feature = "sync"))]
 mod asyncified {
     use super::*;
     use crate::{asyncify_op, driver::op::read};

monoio/src/fs/file/windows.rs

@@ -3,9 +3,9 @@ use std::{
     os::windows::io::{AsRawHandle, RawHandle},
 };
 
-#[cfg(all(feature = "asyncify-op", not(feature = "iouring")))]
+#[cfg(all(not(feature = "iouring"), feature = "sync"))]
 pub(crate) use asyncified::*;
-#[cfg(any(not(feature = "asyncify-op"), feature = "iouring"))]
+#[cfg(any(feature = "iouring", not(feature = "sync")))]
 pub(crate) use blocking::*;
 use windows_sys::Win32::Networking::WinSock::WSABUF;
 
@@ -74,7 +74,7 @@ pub(crate) async fn write_vectored<T: IoVecBuf>(
     (Ok(total_bytes_write), buf_vec)
 }
 
-#[cfg(any(not(feature = "asyncify-op"), feature = "iouring"))]
+#[cfg(any(feature = "iouring", not(feature = "sync")))]
 mod blocking {
     use super::*;
 
@@ -143,14 +143,19 @@ mod blocking {
     }
 }
 
-#[cfg(all(feature = "asyncify-op", not(feature = "iouring")))]
+#[cfg(all(not(feature = "iouring"), feature = "sync"))]
 mod asyncified {
     use super::*;
     use crate::{asyncify_op, driver::op::read, fs::asyncify};
 
     asyncify_op!(read<IoBufMut>(read::read, IoBufMut::write_ptr, IoBufMut::bytes_total));
     asyncify_op!(read_at<IoBufMut>(read::read_at, IoBufMut::write_ptr, IoBufMut::bytes_total, pos: u64));
 
+    /// The `readv` implement on windows.
+    ///
+    /// Due to windows does not have syscall like `readv`, so we need to simulate it by ourself.
+    ///
+    /// This function is just to fill each buffer by calling the `read` function.
     pub(crate) async fn read_vectored<T: IoVecBufMut>(
         fd: SharedFd,
         mut buf_vec: T,

monoio/src/fs/mod.rs

@@ -69,8 +69,7 @@ use crate::driver::op::Op;
 /// - The blocking task returned an error, in which case the error is propagated.
 /// - The background task failed to complete due to an internal error, in which case an error with
 ///   `io::ErrorKind::Other` is returned.
-#[cfg(feature = "asyncify-op")]
-#[allow(unused)]
+#[cfg(all(feature = "sync", not(feature = "iouring")))]
 pub(crate) async fn asyncify<F, T>(f: F) -> io::Result<T>
 where
     F: FnOnce() -> io::Result<T> + Send + 'static,
@@ -93,7 +92,7 @@ where
 /// This macro is intended to abstract the process of creating asynchronous functions for
 /// operations that involve reading or writing buffers, making it easier to create functions
 /// that perform system-level I/O asynchronously.
-#[cfg(feature = "asyncify-op")]
+#[cfg(all(feature = "sync", not(feature = "iouring")))]
 #[macro_export]
 macro_rules! asyncify_op {
     ($fn_name:ident<$Trait: ident>($read_op:expr, $buf_ptr_expr:expr, $len_expr:expr $(, $extra_param:ident : $typ: ty)?) $(,)?) => {

monoio/tests/fs_file.rs

@@ -1,5 +1,3 @@
-#![cfg(not(feature = "asyncify-op"))]
-
 use std::io::{prelude::*, SeekFrom};
 #[cfg(unix)]
 use std::os::unix::io::{AsRawFd, FromRawFd, RawFd};

monoio/tests/fs_file_asyncify.rs

@@ -1,5 +1,4 @@
-#![cfg(feature = "asyncify-op")]
-
+#![cfg(feature = "sync")]
 use std::io::prelude::*;
 #[cfg(windows)]
 use std::os::windows::io::{AsRawHandle, FromRawHandle, RawHandle as RawFd};