X-Git-Url: http://plrg.eecs.uci.edu/git/?p=folly.git;a=blobdiff_plain;f=folly%2FSynchronized.h;h=7b016a1436bd5985232ef68ff35fc7df7645ee37;hp=5b6f9fc0e6b6372f9b132f2e6aed469f83fc66cb;hb=4bfbe0a10e914c3626e16cfdb9e87508e63b065f;hpb=ed8c80a0e0988e4ce687f51ca832a00e4a6b7930

diff --git a/folly/Synchronized.h b/folly/Synchronized.h
index 5b6f9fc0..7b016a14 100644
--- a/folly/Synchronized.h
+++ b/folly/Synchronized.h
@@ -1,5 +1,5 @@
 /*
- * Copyright 2017 Facebook, Inc.
+ * Copyright 2011-present Facebook, Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -491,10 +491,10 @@ struct Synchronized : public SynchronizedBase<
 
   /**
    * Lets you construct non-movable types in-place. Use the constexpr
-   * instance `construct_in_place` as the first argument.
+   * instance `in_place` as the first argument.
    */
   template <typename... Args>
-  explicit Synchronized(construct_in_place_t, Args&&... args)
+  explicit Synchronized(in_place_t, Args&&... args)
       : datum_(std::forward<Args>(args)...) {}
 
   /**
@@ -626,7 +626,7 @@ struct Synchronized : public SynchronizedBase<
 
   /**
    * Attempts to acquire for a given number of milliseconds. If
-   * acquisition is unsuccessful, the returned LockedPtr is NULL.
+   * acquisition is unsuccessful, the returned LockedPtr is nullptr.
    *
    * NOTE: This API is deprecated.  Use lock(), wlock(), or rlock() instead.
    * In the future it will be marked with a deprecation attribute to emit
@@ -638,7 +638,7 @@ struct Synchronized : public SynchronizedBase<
 
   /**
    * Attempts to acquire for a given number of milliseconds. If
-   * acquisition is unsuccessful, the returned ConstLockedPtr is NULL.
+   * acquisition is unsuccessful, the returned ConstLockedPtr is nullptr.
    *
    * NOTE: This API is deprecated.  Use lock(), wlock(), or rlock() instead.
    * In the future it will be marked with a deprecation attribute to emit
@@ -691,6 +691,15 @@ struct Synchronized : public SynchronizedBase<
     swap(datum_, rhs);
   }
 
+  /**
+   * Assign another datum and return the original value. Recommended
+   * because it keeps the mutex held only briefly.
+   */
+  T exchange(T&& rhs) {
+    swap(rhs);
+    return std::move(rhs);
+  }
+
   /**
    * Copies datum to a given target.
    */
@@ -757,7 +766,7 @@ using LockedPtrType = typename std::conditional<
     std::is_const<SynchronizedType>::value,
     typename SynchronizedType::ConstLockedPtr,
     typename SynchronizedType::LockedPtr>::type;
-} // detail
+} // namespace detail
 
 /**
  * A helper base class for implementing LockedPtr.
@@ -1320,7 +1329,7 @@ void swap(Synchronized<T, M>& lhs, Synchronized<T, M>& rhs) {
  */
 #define SYNCHRONIZED(...)                                             \
   FOLLY_PUSH_WARNING                                                  \
-  FOLLY_GCC_DISABLE_WARNING(shadow)                                   \
+  FOLLY_GCC_DISABLE_WARNING("-Wshadow")                               \
   FOLLY_MSVC_DISABLE_WARNING(4189) /* initialized but unreferenced */ \
   FOLLY_MSVC_DISABLE_WARNING(4456) /* declaration hides local */      \
   FOLLY_MSVC_DISABLE_WARNING(4457) /* declaration hides parameter */  \