(svn r26349) -Add: Optional recursive locking of mutexes.

src/thread/thread.h

@@ -66,13 +66,19 @@ public:
 
 	/**
 	 * Begin the critical section
+	 * @param allow_recursive Whether recursive locking is intentional.
+	 *                        If false, NOT_REACHED() will be called when the mutex is already locked
+	 *                        by the current thread.
 	 */
-	virtual void BeginCritical() = 0;
+	virtual void BeginCritical(bool allow_recursive = false) = 0;
 
 	/**
 	 * End of the critical section
+	 * @param allow_recursive Whether recursive unlocking is intentional.
+	 *                        If false, NOT_REACHED() will be called when the mutex was locked more
+	 *                        than once by the current thread.
 	 */
-	virtual void EndCritical() = 0;
+	virtual void EndCritical(bool allow_recursive = false) = 0;
 
 	/**
 	 * Wait for a signal to be send.

src/thread/thread_none.cpp

@@ -21,8 +21,8 @@
 /** Mutex that doesn't do locking because it ain't needed when there're no threads */
 class ThreadMutex_None : public ThreadMutex {
 public:
-	virtual void BeginCritical() {}
-	virtual void EndCritical() {}
+	virtual void BeginCritical(bool allow_recursive = false) {}
+	virtual void EndCritical(bool allow_recursive = false) {}
 	virtual void WaitForSignal() {}
 	virtual void SendSignal() {}
 };

src/thread/thread_os2.cpp

@@ -95,9 +95,10 @@ class ThreadMutex_OS2 : public ThreadMutex {
 private:
 	HMTX mutex; ///< The mutex.
 	HEV event;  ///< Event for waiting.
+	uint recursive_count;     ///< Recursive lock count.
 
 public:
-	ThreadMutex_OS2()
+	ThreadMutex_OS2() : recursive_count(0)
 	{
 		DosCreateMutexSem(NULL, &mutex, 0, FALSE);
 		DosCreateEventSem(NULL, &event, 0, FALSE);
@@ -109,21 +110,30 @@ public:
 		DosCloseEventSem(event);
 	}
 
-	/* virtual */ void BeginCritical()
+	/* virtual */ void BeginCritical(bool allow_recursive = false)
 	{
+		/* os2 mutex is recursive by itself */
 		DosRequestMutexSem(mutex, (unsigned long) SEM_INDEFINITE_WAIT);
+		this->recursive_count++;
+		if (!allow_recursive && this->recursive_count != 1) NOT_REACHED();
 	}
 
-	/* virtual */ void EndCritical()
+	/* virtual */ void EndCritical(bool allow_recursive = false)
 	{
+		if (!allow_recursive && this->recursive_count != 1) NOT_REACHED();
+		this->recursive_count--;
 		DosReleaseMutexSem(mutex);
 	}
 
 	/* virtual */ void WaitForSignal()
 	{
+		assert(this->recursive_count == 1); // Do we need to call Begin/EndCritical multiple times otherwise?
+		uint old_recursive_count = this->recursive_count;
+		this->recursive_count = 0;
 		this->EndCritical();
 		DosWaitEventSem(event, SEM_INDEFINITE_WAIT);
 		this->BeginCritical();
+		this->recursive_count = this->recursive_count;
 	}
 
 	/* virtual */ void SendSignal()

src/thread/thread_pthread.cpp

@@ -98,9 +98,11 @@ private:
 	pthread_mutex_t mutex;    ///< The actual mutex.
 	pthread_cond_t condition; ///< Data for conditional waiting.
 	pthread_mutexattr_t attr; ///< Attributes set for the mutex.
+	pthread_t owner;          ///< Owning thread of the mutex.
+	uint recursive_count;     ///< Recursive lock count.
 
 public:
-	ThreadMutex_pthread()
+	ThreadMutex_pthread() : owner(0), recursive_count(0)
 	{
 		pthread_mutexattr_init(&this->attr);
 		pthread_mutexattr_settype(&this->attr, PTHREAD_MUTEX_ERRORCHECK);
@@ -116,22 +118,45 @@ public:
 		assert(err != EBUSY);
 	}
 
-	/* virtual */ void BeginCritical()
+	bool IsOwnedByCurrentThread() const
 	{
-		int err = pthread_mutex_lock(&this->mutex);
-		assert(err == 0);
+		return this->owner == pthread_self();
 	}
 
-	/* virtual */ void EndCritical()
+	/* virtual */ void BeginCritical(bool allow_recursive = false)
 	{
+		/* pthread mutex is not recursive by itself */
+		if (this->IsOwnedByCurrentThread()) {
+			if (!allow_recursive) NOT_REACHED();
+		} else {
+			int err = pthread_mutex_lock(&this->mutex);
+			assert(err == 0);
+			assert(this->recursive_count == 0);
+			this->owner = pthread_self();
+		}
+		this->recursive_count++;
+	}
+
+	/* virtual */ void EndCritical(bool allow_recursive = false)
+	{
+		assert(this->IsOwnedByCurrentThread());
+		if (!allow_recursive && this->recursive_count != 1) NOT_REACHED();
+		this->recursive_count--;
+		if (this->recursive_count != 0) return;
+		this->owner = 0;
 		int err = pthread_mutex_unlock(&this->mutex);
 		assert(err == 0);
 	}
 
 	/* virtual */ void WaitForSignal()
 	{
+		uint old_recursive_count = this->recursive_count;
+		this->recursive_count = 0;
+		this->owner = 0;
 		int err = pthread_cond_wait(&this->condition, &this->mutex);
 		assert(err == 0);
+		this->owner = pthread_self();
+		this->recursive_count = old_recursive_count;
 	}
 
 	/* virtual */ void SendSignal()

src/thread/thread_win32.cpp

@@ -108,9 +108,10 @@ class ThreadMutex_Win32 : public ThreadMutex {
 private:
 	CRITICAL_SECTION critical_section; ///< The critical section we would enter.
 	HANDLE event;                      ///< Event for signalling.
+	uint recursive_count;     ///< Recursive lock count.
 
 public:
-	ThreadMutex_Win32()
+	ThreadMutex_Win32() : recursive_count(0)
 	{
 		InitializeCriticalSection(&this->critical_section);
 		this->event = CreateEvent(NULL, FALSE, FALSE, NULL);
@@ -122,21 +123,30 @@ public:
 		CloseHandle(this->event);
 	}
 
-	/* virtual */ void BeginCritical()
+	/* virtual */ void BeginCritical(bool allow_recursive = false)
 	{
+		/* windows mutex is recursive by itself */
 		EnterCriticalSection(&this->critical_section);
+		this->recursive_count++;
+		if (!allow_recursive && this->recursive_count != 1) NOT_REACHED();
 	}
 
-	/* virtual */ void EndCritical()
+	/* virtual */ void EndCritical(bool allow_recursive = false)
 	{
+		if (!allow_recursive && this->recursive_count != 1) NOT_REACHED();
+		this->recursive_count--;
 		LeaveCriticalSection(&this->critical_section);
 	}
 
 	/* virtual */ void WaitForSignal()
 	{
+		assert(this->recursive_count == 1); // Do we need to call Begin/EndCritical multiple times otherwise?
+		uint old_recursive_count = this->recursive_count;
+		this->recursive_count = 0;
 		this->EndCritical();
 		WaitForSingleObject(this->event, INFINITE);
 		this->BeginCritical();
+		this->recursive_count = this->recursive_count;
 	}
 
 	/* virtual */ void SendSignal()