From 334c454eec8ba958d8625c091de87cb9fc7d0254 Mon Sep 17 00:00:00 2001
From: Michael Carlberg <c@rlberg.se>
Date: Mon, 26 Dec 2016 10:33:23 +0100
Subject: [PATCH] concurrency_util: Mutex wrapper

---
 include/utils/concurrency.hpp | 94 +++++++++++++++++------------------
 src/utils/concurrency.cpp     | 19 +++++--
 2 files changed, 61 insertions(+), 52 deletions(-)

diff --git a/include/utils/concurrency.hpp b/include/utils/concurrency.hpp
index 69186925..3fde2613 100644
--- a/include/utils/concurrency.hpp
+++ b/include/utils/concurrency.hpp
@@ -1,6 +1,7 @@
 #pragma once
 
 #include <atomic>
+#include <chrono>
 #include <map>
 #include <mutex>
 #include <thread>
@@ -10,6 +11,8 @@
 
 POLYBAR_NS
 
+namespace chrono =std::chrono;
+using namespace std::chrono_literals;
 namespace this_thread = std::this_thread;
 
 using std::atomic;
@@ -17,57 +20,50 @@ using std::map;
 using std::mutex;
 using std::thread;
 
-namespace concurrency_util {
-  namespace locking_strategy {
-    struct no_backoff {
-      bool operator()() {
-        return true;
-      }
-    };
-
-    struct yield_backoff {
-      bool operator()() {
-        this_thread::yield();
-        return false;
-      }
-    };
-  }
-
-  class spin_lock : public non_copyable_mixin<spin_lock> {
-   public:
-    /**
-     * Construct spin_lock
-     */
-    spin_lock() = default;
-
-    /**
-     * Lock using custom strategy
-     */
-    template <typename Backoff>
-    void lock(Backoff backoff) noexcept {
-      while (m_locked.test_and_set(std::memory_order_acquire)) {
-        backoff();
-      }
-    }
-
-    /**
-     * Lock using default strategy
-     */
-    void lock() noexcept {
-      lock(locking_strategy::no_backoff{});
-    }
-
-    /**
-     * Unlock
-     */
-    void unlock() noexcept {
-      m_locked.clear(std::memory_order_release);
-    }
-
-   protected:
-    std::atomic_flag m_locked{false};
+class spin_lock : public non_copyable_mixin<spin_lock> {
+ public:
+  struct no_backoff_strategy {
+    bool operator()();
+  };
+  struct yield_backoff_strategy {
+    bool operator()();
   };
 
+ public:
+  explicit spin_lock() = default;
+
+  template <typename Backoff>
+  void lock(Backoff backoff) noexcept {
+    while (m_locked.test_and_set(std::memory_order_acquire)) {
+      backoff();
+    }
+  }
+
+  void lock() noexcept;
+  void unlock() noexcept;
+
+ protected:
+  std::atomic_flag m_locked{false};
+};
+
+template <typename T>
+class mutex_wrapper : public T {
+ public:
+  template <typename... Args>
+  explicit mutex_wrapper(Args&&... args) : T(forward<Args>(args)...) {}
+
+  void lock() const noexcept {
+    m_mtx.lock();
+  }
+  void unlock() const noexcept {
+    m_mtx.unlock();
+  };
+
+ private:
+  mutable mutex m_mtx;
+};
+
+namespace concurrency_util {
   size_t thread_id(const thread::id id);
 }
 
diff --git a/src/utils/concurrency.cpp b/src/utils/concurrency.cpp
index 058aa5c5..ee320aff 100644
--- a/src/utils/concurrency.cpp
+++ b/src/utils/concurrency.cpp
@@ -2,12 +2,25 @@
 
 POLYBAR_NS
 
+bool spin_lock::no_backoff_strategy::operator()() {
+  return true;
+}
+bool spin_lock::yield_backoff_strategy::operator()() {
+  this_thread::yield();
+  return false;
+}
+void spin_lock::lock() noexcept {
+  lock(no_backoff_strategy{});
+}
+void spin_lock::unlock() noexcept {
+  m_locked.clear(std::memory_order_release);
+}
+
 namespace concurrency_util {
   size_t thread_id(const thread::id id) {
     static size_t idx{1_z};
-    static mutex mtx;
-    static map<thread::id, size_t> ids;
-    std::lock_guard<mutex> lock(mtx);
+    static mutex_wrapper<map<thread::id, size_t>> ids;
+    std::lock_guard<decltype(ids)> lock(ids);
     if (ids.find(id) == ids.end()) {
       ids[id] = idx++;
     }