From 4d15203b9493647776c230048eadb665dc0da39d Mon Sep 17 00:00:00 2001
From: Nishant Kumar Singh <nishant.itbhu@outlook.com>
Date: Thu, 23 May 2019 12:02:37 +0530
Subject: [PATCH] Minor rework of SpinLock class for making it more efficient
 on Unlock() (#33)

* Minor rework of SpinLock class for making it more efficient on Unlock()

* remove tabs in Concurrent.h class
---
 .gitignore                           |  1 +
 AnnService/inc/Helper/Concurrent.h   | 23 ++++++++++++++--------
 AnnService/src/Helper/Concurrent.cpp | 29 ----------------------------
 3 files changed, 16 insertions(+), 37 deletions(-)

diff --git a/.gitignore b/.gitignore
index f87ba727..97378583 100644
--- a/.gitignore
+++ b/.gitignore
@@ -88,3 +88,4 @@ dkms.conf
 /Wrappers/inc/AnnIndex.java
 /Wrappers/inc/AnnClient.java
 /AnnService.users - Copy.props
+/.vs
diff --git a/AnnService/inc/Helper/Concurrent.h b/AnnService/inc/Helper/Concurrent.h
index 41c9c5ff..20ed6b5d 100644
--- a/AnnService/inc/Helper/Concurrent.h
+++ b/AnnService/inc/Helper/Concurrent.h
@@ -4,12 +4,11 @@
 #ifndef _SPTAG_HELPER_CONCURRENT_H_
 #define _SPTAG_HELPER_CONCURRENT_H_
 
-#include <cstdint>
-#include <cstddef> 
+
 #include <atomic>
 #include <condition_variable>
 #include <mutex>
-#include <memory>
+
 
 namespace SPTAG
 {
@@ -21,17 +20,25 @@ namespace Concurrent
 class SpinLock
 {
 public:
-    SpinLock();
-    ~SpinLock();
+    SpinLock() = default;
+
+    void Lock() noexcept 
+    {
+        while (m_lock.test_and_set(std::memory_order_acquire))
+        {
+        }
+    }
 
-    void Lock();
-    void Unlock();
+    void Unlock() noexcept 
+    {
+        m_lock.clear(std::memory_order_release);
+    }
 
     SpinLock(const SpinLock&) = delete;
     SpinLock& operator = (const SpinLock&) = delete;
 
 private:
-    std::atomic_flag m_lock;
+    std::atomic_flag m_lock = ATOMIC_FLAG_INIT;
 };
 
 
diff --git a/AnnService/src/Helper/Concurrent.cpp b/AnnService/src/Helper/Concurrent.cpp
index 36988cb4..cbb1bdb6 100644
--- a/AnnService/src/Helper/Concurrent.cpp
+++ b/AnnService/src/Helper/Concurrent.cpp
@@ -6,35 +6,6 @@
 using namespace SPTAG;
 using namespace SPTAG::Helper::Concurrent;
 
-
-SpinLock::SpinLock()
-    : m_lock()
-{
-    m_lock.clear();
-}
-
-
-SpinLock::~SpinLock()
-{
-}
-
-
-void
-SpinLock::Lock()
-{
-    while (m_lock.test_and_set(std::memory_order_acquire))
-    {
-    }
-}
-
-
-void
-SpinLock::Unlock()
-{
-    m_lock.clear();
-}
-
-
 WaitSignal::WaitSignal()
     : m_isWaiting(false),
       m_unfinished(0)