From c141568b13bdff9e69342b9b6992531dfe7a86ec Mon Sep 17 00:00:00 2001
From: Denes Matetelki <denes.matetelki@gmail.com>
Date: Sat, 26 Feb 2011 22:38:34 +0100
Subject: [PATCH] mutex ctor can have a type, class has tryLock method

---
 include/Mutex.hpp   | 13 ++++++++-----
 src/Mutex.cpp       | 44 +++++++++++++++++++++++++++++++++++++++-----
 test/main_Mutex.cpp | 32 +++++++++++++++++++++-----------
 3 files changed, 68 insertions(+), 21 deletions(-)

diff --git a/include/Mutex.hpp b/include/Mutex.hpp
index e15dd39..6c45510 100644
--- a/include/Mutex.hpp
+++ b/include/Mutex.hpp
@@ -5,16 +5,19 @@
 
 class Mutex 
 {
+
 public:
-	Mutex();
-	~Mutex();
 
-	void lock();
-	void unlock();
+  Mutex(int type = PTHREAD_MUTEX_DEFAULT);
+  ~Mutex();
+
+  void lock();
+  void unlock();
+  bool tryLock(int interval = 0);
 
 private:
 
-	pthread_mutex_t m_mutex;
+  pthread_mutex_t m_mutex;
 
 };
 
diff --git a/src/Mutex.cpp b/src/Mutex.cpp
index 9b051b7..b533ff3 100644
--- a/src/Mutex.cpp
+++ b/src/Mutex.cpp
@@ -1,26 +1,60 @@
 #include "Mutex.hpp"
 
+#include <assert.h>
+#include <time.h>
 
-Mutex::Mutex()
+
+Mutex::Mutex(int type)
 {
-	pthread_mutex_init( &m_mutex, 0 );
+  int ret;
+  if ( type == PTHREAD_MUTEX_DEFAULT ) {
+    ret = pthread_mutex_init( &m_mutex, 0 );
+  } else {
+    pthread_mutexattr_t attr;
+    pthread_mutexattr_init(&attr);
+    pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_ERRORCHECK);
+    ret = pthread_mutex_init( &m_mutex, &attr );
+  }
+  assert( ret == 0 );
 }
 
 
 Mutex::~Mutex()
 {
-	pthread_mutex_destroy ( &m_mutex );
+  int ret = pthread_mutex_destroy ( &m_mutex );
+  assert( ret == 0);
 }
 
 
 void Mutex::lock()
 {
-	pthread_mutex_lock( &m_mutex );
+  int ret = pthread_mutex_lock( &m_mutex );
+  assert( ret == 0);
 }
 
 
 void Mutex::unlock()
 {
-	pthread_mutex_unlock ( &m_mutex );
+  int ret = pthread_mutex_unlock ( &m_mutex );
+  assert( ret == 0);
+}
+
+
+bool Mutex::tryLock(int interval)
+{
+  if ( interval == 0 ) {
+    int result = pthread_mutex_trylock ( &m_mutex );
+    return result == 0;
+  } else {
+    timespec abs_time;
+    clock_gettime ( CLOCK_REALTIME, &abs_time );
+    abs_time.tv_nsec += interval * 1000000;
+    if ( abs_time.tv_nsec >= 1000000000 ) {
+      abs_time.tv_nsec -= 1000000000;
+      abs_time.tv_sec += 1;
+    }
+    int result = pthread_mutex_timedlock ( &m_mutex, &abs_time );
+    return result == 0;
+  }
 }
 
diff --git a/test/main_Mutex.cpp b/test/main_Mutex.cpp
index 2130d4e..1b4f560 100644
--- a/test/main_Mutex.cpp
+++ b/test/main_Mutex.cpp
@@ -1,3 +1,5 @@
+//  g++ -Wall -Wextra src/*.cpp test/main_Mutex.cpp -Iinclude -lpthread -lrt
+
 #include <iostream>
 #include <pthread.h>
 
@@ -8,24 +10,32 @@ int counter = 0;
 
 void *functionC( void* params )
 {
-	m.lock();
-	counter++;
-        std::cout << "Counter value: " << counter << std::endl;
-	m.unlock();
-	return 0;
+  m.lock();
+  counter++;
+  std::cout << "Counter value: " << counter << std::endl;
+  m.unlock();
+  return 0;
 }
 
 
 int main()
 {
-	pthread_t thread1, thread2;
+  pthread_t thread1, thread2;
+
+  pthread_create( &thread1, 0, &functionC, 0 );
+  pthread_create( &thread2, 0, &functionC, 0 );
+
+  pthread_join( thread1, 0 );
+  pthread_join( thread2, 0 );
+
+  Mutex m2(PTHREAD_MUTEX_ERRORCHECK);
 
-        pthread_create( &thread1, 0, &functionC, 0 );
-	pthread_create( &thread2, 0, &functionC, 0 );
+  m2.lock();
+  m2.unlock();
 
-        pthread_join( thread1, 0 );
-	pthread_join( thread2, 0 ); 
+  m2.unlock();
+  m2.unlock();
 
-	return 0;
+    return 0;
 }