QtVersit: Fix crash on access to static variable in multiple threads.

Create a mutex to control access to static variables to ensure they are modified in a thread-safe manner

Change-Id: I8b8cba23c807522e4251ea7fb14563eea8d5c1b3
Reviewed-by: Christopher Adams <chris.adams@jollamobile.com>
Reviewed-by: Konstantin Ritt <ritt.ks@gmail.com>

2 files changed, 9 insertions, 6 deletions

diff --git a/src/versit/qversitutils.cpp b/src/versit/qversitutils.cpp
index e042bac07..076784467 100644
--- a/src/versit/qversitutils.cpp
+++ b/src/versit/qversitutils.cpp
@@ -49,15 +49,14 @@ QT_BEGIN_NAMESPACE_VERSIT
 QTextCodec* VersitUtils::m_previousCodec = 0;
 QList<QByteArrayMatcher>* VersitUtils::m_newlineList = 0;
 QByteArray VersitUtils::m_encodingMap[256];
+QBasicMutex VersitUtils::m_staticLock;
 
 /*!
  * Encode \a ch with \a codec, without adding an byte-order mark
  */
 QByteArray VersitUtils::encode(char ch, QTextCodec* codec)
 {
-    if (codec != m_previousCodec) {
-        changeCodec(codec);
-    }
+    changeCodec(codec);
     return m_encodingMap[(int)ch];
 }
 
@@ -75,9 +74,6 @@ QByteArray VersitUtils::encode(const QByteArray& ba, QTextCodec* codec)
  */
 QList<QByteArrayMatcher>* VersitUtils::newlineList(QTextCodec* codec)
 {
-    if (m_newlineList != 0 && codec == m_previousCodec) {
-        return m_newlineList;
-    }
     changeCodec(codec);
     return m_newlineList;
 }
@@ -86,6 +82,11 @@ QList<QByteArrayMatcher>* VersitUtils::newlineList(QTextCodec* codec)
  * Update the cached tables of pregenerated encoded text with \a codec.
  */
 void VersitUtils::changeCodec(QTextCodec* codec) {
+    QMutexLocker readWriterLocker(&VersitUtils::m_staticLock);
+
+    if (VersitUtils::m_newlineList != 0 && codec == VersitUtils::m_previousCodec)
+        return;
+
     // Build m_encodingMap
     QChar qch;
     QTextCodec::ConverterState state(QTextCodec::IgnoreHeader);
diff --git a/src/versit/qversitutils_p.h b/src/versit/qversitutils_p.h
index 1f51259f9..dd07b3730 100644
--- a/src/versit/qversitutils_p.h
+++ b/src/versit/qversitutils_p.h
@@ -48,6 +48,7 @@
 #include <QtCore/qbytearray.h>
 #include <QtCore/qbytearraymatcher.h>
 #include <QtCore/qlist.h>
+#include <QtCore/QMutex>
 
 #include <QtVersit/qversitproperty.h>
 
@@ -81,6 +82,7 @@ private:
     static QByteArray m_encodingMap[256];
     // List of different newline delimeters, encoded with m_previousCodec
     static QList<QByteArrayMatcher>* m_newlineList;
+    static QBasicMutex m_staticLock;
 };
 
 QT_END_NAMESPACE_VERSIT