diff base/TempWriteFile.h @ 674:920e3880f7b4

* Add TempWriteFile abstraction, use it when exporting audio to avoid clobbering existing file before export is complete

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/base/TempWriteFile.h	Tue Mar 29 17:30:23 2011 +0100
@@ -0,0 +1,60 @@
+/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */
+
+/*
+    Sonic Visualiser
+    An audio file viewer and annotation editor.
+    Centre for Digital Music, Queen Mary, University of London.
+    
+    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.  See the file
+    COPYING included with this distribution for more information.
+*/
+
+#ifndef _TEMP_WRITE_FILE_H_
+#define _TEMP_WRITE_FILE_H_
+
+#include <QTemporaryFile>
+
+/**
+ * A class that manages the creation of a temporary file with a given
+ * prefix and the renaming of that file to the prefix after use.  For
+ * use when saving a file over an existing one, to avoid clobbering
+ * the original before the save is complete.
+ */
+
+class TempWriteFile
+{
+public:
+    TempWriteFile(QString targetFileName); // may throw FileOperationFailed
+
+    /**
+     * Destroy the temporary file object.  If moveToTarget has not
+     * been called, the associated temporary file will be deleted
+     * without being copied to the target location.
+     */
+    ~TempWriteFile();
+
+    /**
+     * Return the name of the temporary file.  Unless the constructor
+     * threw an exception, this file will have been created already
+     * (but it will not be open).
+     *
+     * (If moveToTarget has already been called, return an empty
+     * string.)
+     */
+    QString getTemporaryFilename();
+
+    /**
+     * Rename the temporary file to the target filename.
+     */
+    void moveToTarget();
+
+protected:
+    QString m_target;
+    QString m_temp;
+};
+
+
+#endif