[LyX/master] Make DocFileName::mangledFileName() threadsafe

[Georg Baum]

commit 0de4bc224af34b6f519afb7ab38f190e634b4c7c
Author: Georg Baum <b...@lyx.org>
Date:   Sat Jul 5 12:22:08 2014 +0200

    Make DocFileName::mangledFileName() threadsafe

diff --git a/src/support/FileName.cpp b/src/support/FileName.cpp
index 95880a0..05492f6 100644
--- a/src/support/FileName.cpp
+++ b/src/support/FileName.cpp
@@ -17,6 +17,7 @@
 #include "support/filetools.h"
 #include "support/lassert.h"
 #include "support/lstrings.h"
+#include "support/mutex.h"
 #include "support/qstring_helpers.h"
 #include "support/os.h"
 #include "support/Package.h"
@@ -910,13 +911,15 @@ string DocFileName::outputFileName(string const & path) 
const
 
 string DocFileName::mangledFileName(string const & dir) const
 {
-       // FIXME THREAD
        // Concurrent access to these variables is possible.
 
        // We need to make sure that every DocFileName instance for a given
        // filename returns the same mangled name.
        typedef map<string, string> MangledMap;
        static MangledMap mangledNames;
+       static Mutex mangledMutex;
+       // this locks both access to mangledNames and counter below 
+       Mutex::Locker lock(&mangledMutex);
        MangledMap::const_iterator const it = mangledNames.find(absFileName());
        if (it != mangledNames.end())
                return (*it).second;
@@ -942,7 +945,6 @@ string DocFileName::mangledFileName(string const & dir) 
const
        // Add the extension back on
        mname = support::changeExtension(mname, getExtension(name));
 
-       // FIXME THREAD
        // Prepend a counter to the filename. This is necessary to make
        // the mangled name unique.
        static int counter = 0;