From 962a53d4741e4e2e514f49d9b13831f3cd4e7b48 Mon Sep 17 00:00:00 2001
From: John Kåre Alsaker <john.kare.alsaker@gmail.com>
Date: Mon, 26 Mar 2018 20:52:59 +0200
Subject: Add try_write to RwLock

---
 src/librustc_data_structures/sync.rs | 12 ++++++++++++
 1 file changed, 12 insertions(+)

(limited to 'src/librustc_data_structures')

diff --git a/src/librustc_data_structures/sync.rs b/src/librustc_data_structures/sync.rs
index 184ef136976..0f534f0adec 100644
--- a/src/librustc_data_structures/sync.rs
+++ b/src/librustc_data_structures/sync.rs
@@ -388,6 +388,18 @@ impl<T> RwLock<T> {
         f(&*self.read())
     }
 
+    #[cfg(not(parallel_queries))]
+    #[inline(always)]
+    pub fn try_write(&self) -> Result<WriteGuard<T>, ()> {
+        self.0.try_borrow_mut().map_err(|_| ())
+    }
+
+    #[cfg(parallel_queries)]
+    #[inline(always)]
+    pub fn try_write(&self) -> Result<WriteGuard<T>, ()> {
+        self.0.try_write().ok_or(())
+    }
+
     #[cfg(not(parallel_queries))]
     #[inline(always)]
     pub fn write(&self) -> WriteGuard<T> {
-- 
cgit 1.4.1-3-g733a5