PollFd utility functions

CHANGELOG.md

@@ -6,6 +6,8 @@ This project adheres to [Semantic Versioning](https://semver.org/).
 ## [Unreleased] - ReleaseDate
 ### Added
 
+- Added `any()` and `all()` to `poll::PollFd`.
+  ([#1849](https://github.com/nix-rust/nix/pull/1849))
 - Add `MntFlags` and `unmount` on all of the BSDs.
   ([#1849](https://github.com/nix-rust/nix/pull/1849))
 - Added a 'Statfs::flags' method.

src/poll.rs

@@ -37,6 +37,26 @@ impl PollFd {
         PollFlags::from_bits(self.pollfd.revents)
     }
 
+    /// Returns if any of the events of interest occured in the last call to `poll` or `ppoll`. Will
+    /// only return `None` if the kernel provides status flags that Nix does not know about.
+    ///
+    /// Equivalent to `x.revents()? != PollFlags::empty()`.
+    ///
+    /// This is marginally more efficient than [`PollFd::all`].
+    pub fn any(self) -> Option<bool> {
+        Some(self.revents()? != PollFlags::empty())
+    }
+
+    /// Returns if all the events of interest occured in the last call to `poll` or `ppoll`. Will
+    /// only return `None` if the kernel provides status flags that Nix does not know about.
+    ///
+    /// Equivalent to `x.revents()? & x.events() == x.events()`.
+    ///
+    /// This is marginally less efficient than [`PollFd::any`].
+    pub fn all(self) -> Option<bool> {
+        Some(self.revents()? & self.events() == self.events())
+    }
+
     /// The events of interest for this `PollFd`.
     pub fn events(self) -> PollFlags {
         PollFlags::from_bits(self.pollfd.events).unwrap()