base: Export event related symbols from base in windows

BUG=b:213153157
TEST=presubmit

Change-Id: If4b122b70c11ec1b1591296ff2f67c389fa89671
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosvm/+/3625708
Reviewed-by: Daniel Verkamp <dverkamp@chromium.org>
Reviewed-by: Noah Gold <nkgold@google.com>
Commit-Queue: Vikram Auradkar <auradkar@google.com>
Tested-by: kokoro <noreply+kokoro@google.com>

base/src/lib.rs

@@ -7,6 +7,7 @@ mod clock;
 pub mod descriptor;
 pub mod descriptor_reflection;
 mod errno;
+mod event;
 pub mod external_mapping;
 mod mmap;
 mod notifiers;
@@ -21,6 +22,7 @@ pub use sys::platform;
 pub use alloc::LayoutAllocation;
 pub use clock::{Clock, FakeClock};
 pub use errno::{errno_result, Error, Result};
+pub use event::{Event, EventReadResult, ScopedEvent};
 pub use external_mapping::{Error as ExternalMappingError, Result as ExternalMappingResult, *};
 pub use mmap::{MemoryMapping, MemoryMappingBuilder};
 pub use notifiers::*;
@@ -34,7 +36,6 @@ pub use tube::{Error as TubeError, RecvTube, Result as TubeResult, SendTube, Tub
 
 cfg_if::cfg_if! {
      if #[cfg(unix)] {
-        mod event;
         mod shm;
         mod wait_context;
 
@@ -42,12 +43,12 @@ cfg_if::cfg_if! {
 
         pub use unix::net::*;
 
-        pub use event::{Event, EventReadResult, ScopedEvent};
         pub use platform::{MemoryMappingBuilderUnix, Unix as MemoryMappingUnix};
         pub use shm::SharedMemory;
         pub use wait_context::{EventToken, EventType, TriggeredEvent, WaitContext};
      } else if #[cfg(windows)] {
         pub use platform::MemoryMappingBuilderWindows;
+        pub use platform::EventExt;
         pub use tube::{deserialize_and_recv, serialize_and_send, set_duplicate_handle_tube, set_alias_pid, DuplicateHandleTube};
      } else {
         compile_error!("Unsupported platform");

base/src/sys/windows/win/event.rs

@@ -30,7 +30,10 @@ use winapi::{
 };
 
 use super::{errno_result, Error, RawDescriptor, Result};
-use crate::descriptor::{AsRawDescriptor, FromRawDescriptor, IntoRawDescriptor, SafeDescriptor};
+use crate::{
+    descriptor::{AsRawDescriptor, FromRawDescriptor, IntoRawDescriptor, SafeDescriptor},
+    Event as CrateEvent,
+};
 
 /// A safe wrapper around Windows synchapi methods used to mimic Linux eventfd (man 2 eventfd).
 /// Since the eventfd isn't using "EFD_SEMAPHORE", we don't need to keep count so we can just use
@@ -41,6 +44,16 @@ pub struct Event {
     event_handle: SafeDescriptor,
 }
 
+pub trait EventExt {
+    fn reset(&self) -> Result<()>;
+}
+
+impl EventExt for CrateEvent {
+    fn reset(&self) -> Result<()> {
+        self.0.reset()
+    }
+}
+
 /// Wrapper around the return value of doing a read on an EventFd which distinguishes between
 /// getting a valid count of the number of times the eventfd has been written to and timing out
 /// waiting for the count to be non-zero.

cros_async/src/sys/windows/event.rs

@@ -3,7 +3,7 @@
 // found in the LICENSE file.
 
 use crate::{AsyncError, AsyncResult, EventAsync, Executor};
-use base::Event;
+use base::{Event, EventExt};
 
 impl EventAsync {
     pub fn new(event: Event, ex: &Executor) -> AsyncResult<EventAsync> {