threads and monitor

src/Core/Monitor.h

@@ -0,0 +1,175 @@
+/*//////////////////////////////////////////////////////////////////////////////
+// CMT Cosmic Muon Tomography project //////////////////////////////////////////
+////////////////////////////////////////////////////////////////////////////////
+
+  Copyright (c) 2014, Universita' degli Studi di Padova, INFN sez. di Padova
+  All rights reserved
+
+  Authors: Andrea Rigoni Garola < andrea.rigoni@pd.infn.it >
+
+  ------------------------------------------------------------------
+  This library is free software;  you  can  redistribute  it  and/or
+  modify it  under the  terms  of  the  GNU  Lesser  General  Public
+  License as published  by  the  Free  Software  Foundation;  either
+  version 3.0 of the License, or (at your option) any later version.
+
+  This library is  distributed in  the hope that it will  be useful,
+  but  WITHOUT ANY WARRANTY;  without  even  the implied warranty of
+  MERCHANTABILITY  or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+  Lesser General Public License for more details.
+
+  You should have received a copy of  the GNU Lesser General  Public
+  License along with this library.
+
+//////////////////////////////////////////////////////////////////////////////*/
+
+#ifndef U_CORE_MONITOR_H
+#define U_CORE_MONITOR_H
+
+#include <mutex>
+#include <condition_variable>
+#include <chrono>
+#include <utility>
+
+namespace uLib {
+
+/**
+ * @brief Mutex class wraps std::timed_mutex and is used for thread synchronization.
+ */
+class Mutex {
+public:
+  Mutex() = default;
+  ~Mutex() = default;
+
+  /** @brief Locks the mutex, blocking if necessary. */
+  void Lock() { m_Mutex.lock(); }
+
+  /** @brief Unlocks the mutex. */
+  void Unlock() { m_Mutex.unlock(); }
+
+  /** @brief Tries to lock the mutex without blocking. */
+  bool TryLock() { return m_Mutex.try_lock(); }
+
+  /** @brief Tries to lock the mutex within a timeout in milliseconds. */
+  bool TryLockFor(int timeout_ms) {
+      if (timeout_ms < 0) { Lock(); return true; }
+      return m_Mutex.try_lock_for(std::chrono::milliseconds(timeout_ms));
+  }
+
+  /** @brief RAII helper for scoped locking. */
+  class ScopedLock {
+  public:
+    ScopedLock(Mutex &mutex) : m_Mutex(mutex) { m_Mutex.Lock(); }
+    ~ScopedLock() { m_Mutex.Unlock(); }
+  private:
+    Mutex &m_Mutex;
+    // Non-copyable
+    ScopedLock(const ScopedLock&) = delete;
+    ScopedLock& operator=(const ScopedLock&) = delete;
+  };
+
+  /** @brief Returns the underlying std::timed_mutex. */
+  std::timed_mutex& GetNative() { return m_Mutex; }
+
+private:
+  std::timed_mutex m_Mutex;
+  // Non-copyable
+  Mutex(const Mutex &) = delete;
+  Mutex &operator=(const Mutex &) = delete;
+};
+
+namespace detail {
+
+/** @brief Internal implementation for the ULIB_MUTEX_LOCK macros. */
+class ScopedTimedLock {
+public:
+    ScopedTimedLock(Mutex& mutex, int timeout_ms) 
+        : m_RawMutex(nullptr), m_MutexWrapper(&mutex), m_Locked(false) {
+        m_Locked = m_MutexWrapper->TryLockFor(timeout_ms);
+    }
+    
+    ScopedTimedLock(std::timed_mutex& mutex, int timeout_ms) 
+        : m_RawMutex(&mutex), m_MutexWrapper(nullptr), m_Locked(false) {
+        if (timeout_ms < 0) { m_RawMutex->lock(); m_Locked = true; }
+        else m_Locked = m_RawMutex->try_lock_for(std::chrono::milliseconds(timeout_ms));
+    }
+
+    ~ScopedTimedLock() {
+        if (m_Locked) {
+            if (m_RawMutex) m_RawMutex->unlock();
+            else if (m_MutexWrapper) m_MutexWrapper->Unlock();
+        }
+    }
+    
+    operator bool() const { return m_Locked; }
+    void unlock() { if (m_Locked) { 
+        if (m_RawMutex) m_RawMutex->unlock();
+        else if (m_MutexWrapper) m_MutexWrapper->Unlock();
+        m_Locked = false; 
+    } }
+
+private:
+    std::timed_mutex* m_RawMutex = nullptr;
+    Mutex* m_MutexWrapper = nullptr;
+    bool m_Locked;
+    
+    // Non-copyable/movable to be safe in the 'for' loop
+    ScopedTimedLock(const ScopedTimedLock&) = delete;
+    ScopedTimedLock& operator=(const ScopedTimedLock&) = delete;
+    ScopedTimedLock(ScopedTimedLock&&) = default; 
+};
+
+inline ScopedTimedLock makeScopedMutexLock(Mutex& mutex, int timeout_ms) {
+    return ScopedTimedLock(mutex, timeout_ms);
+}
+
+inline ScopedTimedLock makeScopedMutexLock(std::timed_mutex& mutex, int timeout_ms) {
+    return ScopedTimedLock(mutex, timeout_ms);
+}
+
+} // namespace detail
+
+/**
+ * @brief Macro for block-scoped locking of a static mutex.
+ * @param timeout Timeout in ms (-1 for infinite).
+ */
+#define ULIB_STATIC_LOCK(timeout) \
+    static std::timed_mutex __ulib_static_mutex; \
+    for (auto __ulib_lock = uLib::detail::makeScopedMutexLock(__ulib_static_mutex, timeout); \
+         __ulib_lock; \
+         __ulib_lock.unlock())
+
+/**
+ * @brief Macro for block-scoped locking of a provided mutex.
+ * @param mutex The uLib::Mutex or std::timed_mutex to lock.
+ * @param timeout Timeout in ms (-1 for infinite).
+ */
+#define ULIB_MUTEX_LOCK(mutex, timeout) \
+    for (auto __ulib_lock = uLib::detail::makeScopedMutexLock(mutex, timeout); \
+         __ulib_lock; \
+         __ulib_lock.unlock())
+
+/**
+ * @brief Monitor class provides a base for objects that need thread-safe access.
+ */
+template <typename T>
+class Monitor {
+protected:
+  T* m_Resource;
+  Mutex m_Mutex;
+
+public:
+  Monitor(T* resource) : m_Resource(resource) {}
+  virtual ~Monitor() { delete m_Resource; }
+
+  /** @brief Thread-safe access to the resource through a lambda. */
+  template <typename F>
+  auto Access(F f) -> decltype(f(*m_Resource)) {
+    Mutex::ScopedLock lock(m_Mutex);
+    return f(*m_Resource);
+  }
+};
+
+} // namespace uLib
+
+#endif // U_CORE_MONITOR_H