Fix problems that occurred when multiple threads were trying to read/convert files at the same time (ie: indexing and previewing threads in the GUI calling internfile()). Either get rid of or lock-protect all shared data, eliminate misc initialization possible conflicts by using static initializers. Hopefuly closes issue #51

src/utils/execmd.cpp

@@ -19,7 +19,6 @@
 
 #include <stdlib.h>
 #include <unistd.h>
-#include <pthread.h>
 #include <sys/stat.h>
 #include <sys/types.h>
 #include <sys/wait.h>
@@ -44,6 +43,7 @@
 #include "smallut.h"
 #include "netcon.h"
 #include "closefrom.h"
+#include "ptmutex.h"
 
 #ifndef NO_NAMESPACES
 using namespace std;
@@ -316,38 +316,20 @@ private:
 // The netcon selectloop that doexec() uses for reading/writing would
 // be complicated to render thread-safe. Use locking to ensure only
 // one thread in there
-class ExecLocking {
-public:
-    pthread_mutex_t m_mutex;
-    ExecLocking() 
-    {
-	pthread_mutex_init(&m_mutex, 0);
-    }
-};
-ExecLocking o_lock;
-class ExecLocker {
-public:
-    ExecLocker()
-    {
-	pthread_mutex_lock(&o_lock.m_mutex);
-    }
-    ~ExecLocker()
-    {
-	pthread_mutex_unlock(&o_lock.m_mutex);
-    }
-};
+static PTMutexInit o_lock;
 
 int ExecCmd::doexec(const string &cmd, const list<string>& args,
 		    const string *input, string *output)
 {
+    // Only one thread allowed in here...
+    PTMutexLocker locker(o_lock);
+
     if (startExec(cmd, args, input != 0, output != 0) < 0) {
 	return -1;
     }
 
     // Cleanup in case we return early
     ExecCmdRsrc e(this);
-    // Only one thread allowed in here...
-    ExecLocker locker;
 
     int ret = 0;
     if (input || output) {

src/utils/ptmutex.h

@@ -0,0 +1,52 @@
+/* Copyright (C) 2011 J.F.Dockes
+ *   This program is free software; you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation; either version 2 of the License, or
+ *   (at your option) any later version.
+ *
+ *   This program 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 General Public License for more details.
+ *
+ *   You should have received a copy of the GNU General Public License
+ *   along with this program; if not, write to the
+ *   Free Software Foundation, Inc.,
+ *   59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+ */
+#ifndef _PTMUTEX_H_INCLUDED_
+#define _PTMUTEX_H_INCLUDED_
+
+#include <pthread.h>
+
+/// A trivial wrapper/helper for pthread mutex locks
+
+
+/// Init lock. Used as a single PTMutexInit static object.
+class PTMutexInit {
+public:
+    pthread_mutex_t m_mutex;
+    PTMutexInit() 
+    {
+	pthread_mutex_init(&m_mutex, 0);
+    }
+};
+
+/// Take the lock when constructed, release when deleted
+class PTMutexLocker {
+public:
+    PTMutexLocker(PTMutexInit& l) : m_lock(l)
+    {
+	m_status = pthread_mutex_lock(&m_lock.m_mutex);
+    }
+    ~PTMutexLocker()
+    {
+	pthread_mutex_unlock(&m_lock.m_mutex);
+    }
+    int ok() {return m_status == 0;}
+private:
+    PTMutexInit& m_lock;
+    int m_status;
+};
+
+#endif /* _PTMUTEX_H_INCLUDED_ */