Optimize QFSFileEnginePrivate::canonicalized() by using realpath()

In our benchmark, this makes QFileInfo.canonical*Path() up
to 50% faster. This should also improve application startup time.
Let's see if it works on all Unices and Symbian.

Reviewed-by: mariusSO

1 files changed, 12 insertions, 0 deletions

diff --git a/src/corelib/io/qfsfileengine.cpp b/src/corelib/io/qfsfileengine.cpp
index 3cf9b7e..6aace2c 100644
--- a/src/corelib/io/qfsfileengine.cpp
+++ b/src/corelib/io/qfsfileengine.cpp
@@ -55,6 +55,7 @@
 #include "private/qcore_unix_p.h"
 #endif
 #include <stdio.h>
+#include <stdlib.h>
 
 QT_BEGIN_NAMESPACE
 
@@ -137,6 +138,17 @@ QString QFSFileEnginePrivate::canonicalized(const QString &path)
     if (path.isEmpty())
         return path;
 
+#if defined(Q_OS_UNIX) || defined(Q_OS_SYMBIAN)
+    // FIXME let's see if this stuff works, then we might be able to remove some of the other code
+    const char *fileName = path.toLocal8Bit().constData();
+    char *ret = realpath(fileName, (char*)0);
+    if (ret) {
+        QString canonicalPath = QDir::cleanPath(QString::fromLocal8Bit(ret));
+        free(ret);
+        return canonicalPath;
+    }
+#endif
+
     QFileInfo fi;
     const QChar slash(QLatin1Char('/'));
     QString tmpPath = path;