Merge #637

637: Apply unreachable_pub lint r=jeehoonkang a=taiki-e

`unreachable_pub` lint warns items that are marked as `pub` but are not actually included in the public API, and suggests using `pub(crate)` instead.

`pub(crate)` is a bit more verbose than `pub`, but this should make it easier to review changes that make it difficult to tell if it will break API or not just by looking at the diff like #617 (comment). Especially, there are many such codes in crossbeam-channel and crossbeam-epoch. (Hopefully, after this patch, we can basically consider all items marked `pub` are public APIs, except for items that have been explicitly hidden from the public API by `#[doc(hidden)]`.)

This lint is known to have some false positives, but the crossbeam doesn't seem to be affected.

Co-authored-by: Taiki Endo <te316e89@gmail.com>

Author: bors[bot]

crossbeam-channel/src/channel.rs

@@ -1485,7 +1485,7 @@ impl<T> SelectHandle for Receiver<T> {
 }
 
 /// Writes a message into the channel.
-pub unsafe fn write<T>(s: &Sender<T>, token: &mut Token, msg: T) -> Result<(), T> {
+pub(crate) unsafe fn write<T>(s: &Sender<T>, token: &mut Token, msg: T) -> Result<(), T> {
     match &s.flavor {
         SenderFlavor::Array(chan) => chan.write(token, msg),
         SenderFlavor::List(chan) => chan.write(token, msg),
@@ -1494,7 +1494,7 @@ pub unsafe fn write<T>(s: &Sender<T>, token: &mut Token, msg: T) -> Result<(), T
 }
 
 /// Reads a message from the channel.
-pub unsafe fn read<T>(r: &Receiver<T>, token: &mut Token) -> Result<T, ()> {
+pub(crate) unsafe fn read<T>(r: &Receiver<T>, token: &mut Token) -> Result<T, ()> {
     match &r.flavor {
         ReceiverFlavor::Array(chan) => chan.read(token),
         ReceiverFlavor::List(chan) => chan.read(token),

crossbeam-channel/src/counter.rs

@@ -21,7 +21,7 @@ struct Counter<C> {
 }
 
 /// Wraps a channel into the reference counter.
-pub fn new<C>(chan: C) -> (Sender<C>, Receiver<C>) {
+pub(crate) fn new<C>(chan: C) -> (Sender<C>, Receiver<C>) {
     let counter = Box::into_raw(Box::new(Counter {
         senders: AtomicUsize::new(1),
         receivers: AtomicUsize::new(1),
@@ -34,7 +34,7 @@ pub fn new<C>(chan: C) -> (Sender<C>, Receiver<C>) {
 }
 
 /// The sending side.
-pub struct Sender<C> {
+pub(crate) struct Sender<C> {
     counter: *mut Counter<C>,
 }
 
@@ -45,7 +45,7 @@ impl<C> Sender<C> {
     }
 
     /// Acquires another sender reference.
-    pub fn acquire(&self) -> Sender<C> {
+    pub(crate) fn acquire(&self) -> Sender<C> {
         let count = self.counter().senders.fetch_add(1, Ordering::Relaxed);
 
         // Cloning senders and calling `mem::forget` on the clones could potentially overflow the
@@ -63,7 +63,7 @@ impl<C> Sender<C> {
     /// Releases the sender reference.
     ///
     /// Function `disconnect` will be called if this is the last sender reference.
-    pub unsafe fn release<F: FnOnce(&C) -> bool>(&self, disconnect: F) {
+    pub(crate) unsafe fn release<F: FnOnce(&C) -> bool>(&self, disconnect: F) {
         if self.counter().senders.fetch_sub(1, Ordering::AcqRel) == 1 {
             disconnect(&self.counter().chan);
 
@@ -89,7 +89,7 @@ impl<C> PartialEq for Sender<C> {
 }
 
 /// The receiving side.
-pub struct Receiver<C> {
+pub(crate) struct Receiver<C> {
     counter: *mut Counter<C>,
 }
 
@@ -100,7 +100,7 @@ impl<C> Receiver<C> {
     }
 
     /// Acquires another receiver reference.
-    pub fn acquire(&self) -> Receiver<C> {
+    pub(crate) fn acquire(&self) -> Receiver<C> {
         let count = self.counter().receivers.fetch_add(1, Ordering::Relaxed);
 
         // Cloning receivers and calling `mem::forget` on the clones could potentially overflow the
@@ -118,7 +118,7 @@ impl<C> Receiver<C> {
     /// Releases the receiver reference.
     ///
     /// Function `disconnect` will be called if this is the last receiver reference.
-    pub unsafe fn release<F: FnOnce(&C) -> bool>(&self, disconnect: F) {
+    pub(crate) unsafe fn release<F: FnOnce(&C) -> bool>(&self, disconnect: F) {
         if self.counter().receivers.fetch_sub(1, Ordering::AcqRel) == 1 {
             disconnect(&self.counter().chan);
 

crossbeam-channel/src/flavors/array.rs

@@ -52,7 +52,7 @@ impl Default for ArrayToken {
 }
 
 /// Bounded channel based on a preallocated array.
-pub struct Channel<T> {
+pub(crate) struct Channel<T> {
     /// The head of the channel.
     ///
     /// This value is a "stamp" consisting of an index into the buffer, a mark bit, and a lap, but
@@ -95,7 +95,7 @@ pub struct Channel<T> {
 
 impl<T> Channel<T> {
     /// Creates a bounded channel of capacity `cap`.
-    pub fn with_capacity(cap: usize) -> Self {
+    pub(crate) fn with_capacity(cap: usize) -> Self {
         assert!(cap > 0, "capacity must be positive");
 
         // Compute constants `mark_bit` and `one_lap`.
@@ -138,12 +138,12 @@ impl<T> Channel<T> {
     }
 
     /// Returns a receiver handle to the channel.
-    pub fn receiver(&self) -> Receiver<'_, T> {
+    pub(crate) fn receiver(&self) -> Receiver<'_, T> {
         Receiver(self)
     }
 
     /// Returns a sender handle to the channel.
-    pub fn sender(&self) -> Sender<'_, T> {
+    pub(crate) fn sender(&self) -> Sender<'_, T> {
         Sender(self)
     }
 
@@ -219,7 +219,7 @@ impl<T> Channel<T> {
     }
 
     /// Writes a message into the channel.
-    pub unsafe fn write(&self, token: &mut Token, msg: T) -> Result<(), T> {
+    pub(crate) unsafe fn write(&self, token: &mut Token, msg: T) -> Result<(), T> {
         // If there is no slot, the channel is disconnected.
         if token.array.slot.is_null() {
             return Err(msg);
@@ -309,7 +309,7 @@ impl<T> Channel<T> {
     }
 
     /// Reads a message from the channel.
-    pub unsafe fn read(&self, token: &mut Token) -> Result<T, ()> {
+    pub(crate) unsafe fn read(&self, token: &mut Token) -> Result<T, ()> {
         if token.array.slot.is_null() {
             // The channel is disconnected.
             return Err(());
@@ -327,7 +327,7 @@ impl<T> Channel<T> {
     }
 
     /// Attempts to send a message into the channel.
-    pub fn try_send(&self, msg: T) -> Result<(), TrySendError<T>> {
+    pub(crate) fn try_send(&self, msg: T) -> Result<(), TrySendError<T>> {
         let token = &mut Token::default();
         if self.start_send(token) {
             unsafe { self.write(token, msg).map_err(TrySendError::Disconnected) }
@@ -337,7 +337,11 @@ impl<T> Channel<T> {
     }
 
     /// Sends a message into the channel.
-    pub fn send(&self, msg: T, deadline: Option<Instant>) -> Result<(), SendTimeoutError<T>> {
+    pub(crate) fn send(
+        &self,
+        msg: T,
+        deadline: Option<Instant>,
+    ) -> Result<(), SendTimeoutError<T>> {
         let token = &mut Token::default();
         loop {
             // Try sending a message several times.
@@ -386,7 +390,7 @@ impl<T> Channel<T> {
     }
 
     /// Attempts to receive a message without blocking.
-    pub fn try_recv(&self) -> Result<T, TryRecvError> {
+    pub(crate) fn try_recv(&self) -> Result<T, TryRecvError> {
         let token = &mut Token::default();
 
         if self.start_recv(token) {
@@ -397,7 +401,7 @@ impl<T> Channel<T> {
     }
 
     /// Receives a message from the channel.
-    pub fn recv(&self, deadline: Option<Instant>) -> Result<T, RecvTimeoutError> {
+    pub(crate) fn recv(&self, deadline: Option<Instant>) -> Result<T, RecvTimeoutError> {
         let token = &mut Token::default();
         loop {
             // Try receiving a message several times.
@@ -448,7 +452,7 @@ impl<T> Channel<T> {
     }
 
     /// Returns the current number of messages inside the channel.
-    pub fn len(&self) -> usize {
+    pub(crate) fn len(&self) -> usize {
         loop {
             // Load the tail, then load the head.
             let tail = self.tail.load(Ordering::SeqCst);
@@ -473,14 +477,14 @@ impl<T> Channel<T> {
     }
 
     /// Returns the capacity of the channel.
-    pub fn capacity(&self) -> Option<usize> {
+    pub(crate) fn capacity(&self) -> Option<usize> {
         Some(self.cap)
     }
 
     /// Disconnects the channel and wakes up all blocked senders and receivers.
     ///
     /// Returns `true` if this call disconnected the channel.
-    pub fn disconnect(&self) -> bool {
+    pub(crate) fn disconnect(&self) -> bool {
         let tail = self.tail.fetch_or(self.mark_bit, Ordering::SeqCst);
 
         if tail & self.mark_bit == 0 {
@@ -493,12 +497,12 @@ impl<T> Channel<T> {
     }
 
     /// Returns `true` if the channel is disconnected.
-    pub fn is_disconnected(&self) -> bool {
+    pub(crate) fn is_disconnected(&self) -> bool {
         self.tail.load(Ordering::SeqCst) & self.mark_bit != 0
     }
 
     /// Returns `true` if the channel is empty.
-    pub fn is_empty(&self) -> bool {
+    pub(crate) fn is_empty(&self) -> bool {
         let head = self.head.load(Ordering::SeqCst);
         let tail = self.tail.load(Ordering::SeqCst);
 
@@ -510,7 +514,7 @@ impl<T> Channel<T> {
     }
 
     /// Returns `true` if the channel is full.
-    pub fn is_full(&self) -> bool {
+    pub(crate) fn is_full(&self) -> bool {
         let tail = self.tail.load(Ordering::SeqCst);
         let head = self.head.load(Ordering::SeqCst);
 
@@ -558,10 +562,10 @@ impl<T> Drop for Channel<T> {
 }
 
 /// Receiver handle to a channel.
-pub struct Receiver<'a, T>(&'a Channel<T>);
+pub(crate) struct Receiver<'a, T>(&'a Channel<T>);
 
 /// Sender handle to a channel.
-pub struct Sender<'a, T>(&'a Channel<T>);
+pub(crate) struct Sender<'a, T>(&'a Channel<T>);
 
 impl<T> SelectHandle for Receiver<'_, T> {
     fn try_select(&self, token: &mut Token) -> bool {

crossbeam-channel/src/flavors/at.rs

@@ -12,10 +12,10 @@ use crate::select::{Operation, SelectHandle, Token};
 use crate::utils;
 
 /// Result of a receive operation.
-pub type AtToken = Option<Instant>;
+pub(crate) type AtToken = Option<Instant>;
 
 /// Channel that delivers a message at a certain moment in time
-pub struct Channel {
+pub(crate) struct Channel {
     /// The instant at which the message will be delivered.
     delivery_time: Instant,
 
@@ -26,21 +26,21 @@ pub struct Channel {
 impl Channel {
     /// Creates a channel that delivers a message at a certain instant in time.
     #[inline]
-    pub fn new_deadline(when: Instant) -> Self {
+    pub(crate) fn new_deadline(when: Instant) -> Self {
         Channel {
             delivery_time: when,
             received: AtomicBool::new(false),
         }
     }
     /// Creates a channel that delivers a message after a certain duration of time.
     #[inline]
-    pub fn new_timeout(dur: Duration) -> Self {
+    pub(crate) fn new_timeout(dur: Duration) -> Self {
         Self::new_deadline(Instant::now() + dur)
     }
 
     /// Attempts to receive a message without blocking.
     #[inline]
-    pub fn try_recv(&self) -> Result<Instant, TryRecvError> {
+    pub(crate) fn try_recv(&self) -> Result<Instant, TryRecvError> {
         // We use relaxed ordering because this is just an optional optimistic check.
         if self.received.load(Ordering::Relaxed) {
             // The message has already been received.
@@ -64,7 +64,7 @@ impl Channel {
 
     /// Receives a message from the channel.
     #[inline]
-    pub fn recv(&self, deadline: Option<Instant>) -> Result<Instant, RecvTimeoutError> {
+    pub(crate) fn recv(&self, deadline: Option<Instant>) -> Result<Instant, RecvTimeoutError> {
         // We use relaxed ordering because this is just an optional optimistic check.
         if self.received.load(Ordering::Relaxed) {
             // The message has already been received.
@@ -103,13 +103,13 @@ impl Channel {
 
     /// Reads a message from the channel.
     #[inline]
-    pub unsafe fn read(&self, token: &mut Token) -> Result<Instant, ()> {
+    pub(crate) unsafe fn read(&self, token: &mut Token) -> Result<Instant, ()> {
         token.at.ok_or(())
     }
 
     /// Returns `true` if the channel is empty.
     #[inline]
-    pub fn is_empty(&self) -> bool {
+    pub(crate) fn is_empty(&self) -> bool {
         // We use relaxed ordering because this is just an optional optimistic check.
         if self.received.load(Ordering::Relaxed) {
             return true;
@@ -127,13 +127,13 @@ impl Channel {
 
     /// Returns `true` if the channel is full.
     #[inline]
-    pub fn is_full(&self) -> bool {
+    pub(crate) fn is_full(&self) -> bool {
         !self.is_empty()
     }
 
     /// Returns the number of messages in the channel.
     #[inline]
-    pub fn len(&self) -> usize {
+    pub(crate) fn len(&self) -> usize {
         if self.is_empty() {
             0
         } else {
@@ -143,7 +143,7 @@ impl Channel {
 
     /// Returns the capacity of the channel.
     #[inline]
-    pub fn capacity(&self) -> Option<usize> {
+    pub(crate) fn capacity(&self) -> Option<usize> {
         Some(1)
     }
 }