backward compatibility fix for QFileInfo::isRoot()

In the old system, QFileInfo("p:/").isRoot() would return false because
the file engine first checks exists(). Assuming P: is not mounted that
would return false.
This change makes QFileInfo::isRoot() check the drive exists.

Reviewed-By: joao

1 files changed, 14 insertions, 2 deletions

diff --git a/src/corelib/io/qfileinfo.cpp b/src/corelib/io/qfileinfo.cpp
index 232a32e..5d632d3 100644
--- a/src/corelib/io/qfileinfo.cpp
+++ b/src/corelib/io/qfileinfo.cpp
@@ -1018,8 +1018,20 @@ bool QFileInfo::isRoot() const
     Q_D(const QFileInfo);
     if (d->isDefaultConstructed)
         return true;
-    if (d->fileEngine == 0)
-        return d->fileEntry.isRoot();
+    if (d->fileEngine == 0) {
+        if (d->fileEntry.isRoot()) {
+#if defined(Q_OS_WIN) || defined(Q_OS_SYMBIAN) 
+            //the path is a drive root, but the drive may not exist
+            //for backward compatibility, return true only if the drive exists
+            if (!d->cache_enabled || !d->metaData.hasFlags(QFileSystemMetaData::ExistsAttribute))
+                QFileSystemEngine::fillMetaData(d->fileEntry, d->metaData, QFileSystemMetaData::ExistsAttribute);
+            return d->metaData.exists();
+#else
+            return true;
+#endif
+        }
+        return false;
+    }
     return d->getFileFlags(QAbstractFileEngine::RootFlag);
 }