Fix some copyright lines in folly/detail/ and folly/test/

[folly.git] / folly / detail / Futex.h

diff --git a/folly/detail/Futex.h b/folly/detail/Futex.h
index a38b4423e057f1ee94e0cddb792417d807832fb6..b8cbcd2e547dd8007efba44d3d812f9cb085f7e2 100644 (file)
--- a/folly/detail/Futex.h
+++ b/folly/detail/Futex.h
@@ -1,5 +1,5 @@
 /*
- * Copyright 2014 Facebook, Inc.
+ * Copyright 2013-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.
@@ -17,19 +17,21 @@
 #pragma once
 
 #include <atomic>
+#include <cassert>
 #include <chrono>
 #include <limits>
-#include <assert.h>
-#include <unistd.h>
+
 #include <boost/noncopyable.hpp>
 
+#include <folly/portability/Unistd.h>
+
 namespace folly { namespace detail {
 
 enum class FutexResult {
   VALUE_CHANGED, /* Futex value didn't match expected */
   AWOKEN,        /* futex wait matched with a futex wake */
   INTERRUPTED,   /* Spurious wake-up or signal caused futex wait failure */
-  TIMEDOUT
+  TIMEDOUT,
 };
 
 /**
@@ -44,7 +46,7 @@ enum class FutexResult {
 template <template <typename> class Atom = std::atomic>
 struct Futex : Atom<uint32_t>, boost::noncopyable {
 
-  explicit Futex(uint32_t init = 0) : Atom<uint32_t>(init) {}
+  explicit constexpr Futex(uint32_t init = 0) : Atom<uint32_t>(init) {}
 
   /** Puts the thread to sleep if this->load() == expected.  Returns true when
    *  it is returning because it has consumed a wake() event, false for any
@@ -102,8 +104,14 @@ struct Futex : Atom<uint32_t>, boost::noncopyable {
     }
   }
 
-  /** Wakens up to count waiters where (waitMask & wakeMask) != 0,
-   *  returning the number of awoken threads. */
+  /** Wakens up to count waiters where (waitMask & wakeMask) !=
+   *  0, returning the number of awoken threads, or -1 if an error
+   *  occurred.  Note that when constructing a concurrency primitive
+   *  that can guard its own destruction, it is likely that you will
+   *  want to ignore EINVAL here (as well as making sure that you
+   *  never touch the object after performing the memory store that
+   *  is the linearization point for unlock or control handoff).
+   *  See https://sourceware.org/bugzilla/show_bug.cgi?id=13690 */
   int futexWake(int count = std::numeric_limits<int>::max(),
                 uint32_t wakeMask = -1);
 
@@ -130,29 +138,31 @@ struct EmulatedFutexAtomic : public std::atomic<T> {
   EmulatedFutexAtomic() noexcept = default;
   constexpr /* implicit */ EmulatedFutexAtomic(T init) noexcept
       : std::atomic<T>(init) {}
-  EmulatedFutexAtomic(const EmulatedFutexAtomic& rhs) = delete;
+  // It doesn't copy or move
+  EmulatedFutexAtomic(EmulatedFutexAtomic&& rhs) = delete;
 };
 
 /* Available specializations, with definitions elsewhere */
 
-template<>
+template <>
 int Futex<std::atomic>::futexWake(int count, uint32_t wakeMask);
 
-template<>
+template <>
 FutexResult Futex<std::atomic>::futexWaitImpl(
       uint32_t expected,
       std::chrono::time_point<std::chrono::system_clock>* absSystemTime,
       std::chrono::time_point<std::chrono::steady_clock>* absSteadyTime,
       uint32_t waitMask);
 
-template<>
+template <>
 int Futex<EmulatedFutexAtomic>::futexWake(int count, uint32_t wakeMask);
 
-template<>
+template <>
 FutexResult Futex<EmulatedFutexAtomic>::futexWaitImpl(
       uint32_t expected,
       std::chrono::time_point<std::chrono::system_clock>* absSystemTime,
       std::chrono::time_point<std::chrono::steady_clock>* absSteadyTime,
       uint32_t waitMask);
 
-}}
+} // namespace detail
+} // namespace folly