From 700d4bbcbf59c4447becbab21a6aa7204a8da2f4 Mon Sep 17 00:00:00 2001
From: Mike Buland <mike@xagasoft.com>
Date: Wed, 6 Nov 2024 16:01:36 -0800
Subject: I believe MyriadFs is now threadsafe.

It could probably be more optimized, but it does work.
---
 src/experimental/debugmutex.cpp |  78 ++++++++++++++++++++++++++++++
 src/experimental/debugmutex.h   | 102 ++++++++++++++++++++++++++++++++++++++++
 2 files changed, 180 insertions(+)
 create mode 100644 src/experimental/debugmutex.cpp
 create mode 100644 src/experimental/debugmutex.h

(limited to 'src/experimental')

diff --git a/src/experimental/debugmutex.cpp b/src/experimental/debugmutex.cpp
new file mode 100644
index 0000000..2b61ae2
--- /dev/null
+++ b/src/experimental/debugmutex.cpp
@@ -0,0 +1,78 @@
+#include "bu/debugmutex.h"
+
+#include "bu/exceptionbase.h"
+
+Bu::DebugMutex::DebugMutex()
+{
+}
+
+Bu::DebugMutex::~DebugMutex()
+{
+}
+
+int Bu::DebugMutex::lock()
+{
+    pthread_t self = pthread_self();
+    mState.lock();
+    bool bFound = false;
+    for( ThreadList::iterator i = lThreads.begin(); i; i++ )
+    {
+        if( (*i) == self )
+        {
+            bFound = true;
+            if( (*i).bLocked == true )
+            {
+                throw Bu::ExceptionBase( Bu::String("Double lock in thread: %1").arg( (*i).sName ).end().getStr() );
+
+            }
+            else
+            {
+                (*i).bLocked = true;
+            }
+            break;
+        }
+    }
+    if( bFound == false )
+    {
+        lThreads.append( ThreadInfo( true ) );
+    }
+    mState.unlock();
+    return Bu::Mutex::lock();
+}
+
+int Bu::DebugMutex::unlock()
+{
+    pthread_t self = pthread_self();
+    mState.lock();
+    bool bFound = false;
+    for( ThreadList::iterator i = lThreads.begin(); i; i++ )
+    {
+        if( (*i) == self )
+        {
+            bFound = true;
+            if( (*i).bLocked == false )
+            {
+                throw Bu::ExceptionBase( Bu::String("Unlock in thread that did not lock: %1").arg( (*i).sName ).end().getStr() );
+
+            }
+            else
+            {
+                (*i).bLocked = false;
+            }
+            break;
+        }
+    }
+    if( bFound == false )
+    {
+        ThreadInfo info( false );
+        throw Bu::ExceptionBase( Bu::String("Unlock in thread that never locked mutex: %1").arg( info.sName ).end().getStr() );
+    }
+    mState.unlock();
+    return Bu::Mutex::unlock();
+}
+
+int Bu::DebugMutex::trylock()
+{
+    return Bu::Mutex::trylock();
+}
+
diff --git a/src/experimental/debugmutex.h b/src/experimental/debugmutex.h
new file mode 100644
index 0000000..ca8ef9f
--- /dev/null
+++ b/src/experimental/debugmutex.h
@@ -0,0 +1,102 @@
+/*
+ * Copyright (C) 2007-2023 Xagasoft, All rights reserved.
+ *
+ * This file is part of the libbu++ library and is released under the
+ * terms of the license contained in the file LICENSE.
+ */
+
+#ifndef BU_DEBUG_MUTEX_H
+#define BU_DEBUG_MUTEX_H
+
+#include "bu/mutex.h"
+#include "bu/list.h"
+#include "bu/string.h"
+
+namespace Bu
+{
+    /**
+     * Simple mutex wrapper.  Currently this doesn't do anything extra for you
+     * except keep all of the functionality together in an OO sorta' way and
+     * keep you from having to worry about cleaning up your mutexes properly,
+     * or initing them.
+     *@ingroup Threading
+     */
+    class DebugMutex : public Mutex
+    {
+    public:
+        /**
+         * Create an unlocked mutex.
+         */
+        DebugMutex();
+        
+        /**
+         * Destroy a mutex.  This can only be done when a mutex is unlocked.
+         * Failure to unlock before destroying a mutex object could cause it to
+         * wait for the mutex to unlock, the odds of which are usually farily
+         * low at deconstruction time.
+         */
+        virtual ~DebugMutex();
+
+        /**
+         * Lock the mutex.  This causes all future calls to lock on this
+         * instance of mutex to block until the first thread that called mutex
+         * unlocks it.  At that point the next thread that called lock will get
+         * a chance to go to work.  Because of the nature of a mutex lock it is
+         * a very bad idea to do any kind of serious or rather time consuming
+         * computation within a locked section.  This can cause thread-deadlock
+         * and your program may hang.
+         */
+        virtual int lock();
+
+        /**
+         * Unlock the mutex.  This allows the next thread that asked for a lock
+         * to lock the mutex and continue with execution.
+         */
+        virtual int unlock();
+
+        /**
+         * Try to lock the mutex.  This is the option to go with if you cannot
+         * avoid putting lengthy operations within a locked section.  trylock
+         * will attempt to lock the mutex, if the mutex is already locked this
+         * function returns immediately with an error code.
+         */
+        virtual int trylock();
+
+    private:
+        Bu::Mutex mState;
+
+        class ThreadInfo
+        {
+        public:
+            ThreadInfo( bool bLocked=false ) :
+                idThread( pthread_self() ),
+                bLocked( bLocked )
+            {
+                char buf[64];
+                if( pthread_getname_np( idThread, buf, 64 ) == 0 )
+                    sName = buf;
+            }
+            ~ThreadInfo() {}
+
+            bool operator==( const ThreadInfo &rhs )
+            {
+                return pthread_equal( idThread, rhs.idThread );
+            }
+
+            bool operator==( const pthread_t &rhs )
+            {
+                return pthread_equal( idThread, rhs );
+            }
+
+            pthread_t idThread;
+            Bu::String sName;
+            bool bLocked;
+        };
+        typedef Bu::List<ThreadInfo> ThreadList;
+        ThreadList lThreads;
+    };
+}
+
+#endif
+
+
-- 
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