QFileSystemIterator/Unix: use QStringDecoder

The end result is a QFileInfo constructed from the QFileSystemEntry;
QFileSystemEntry's API will at some point convert the NativePath (QBA on
Unix) to a QString, e.g. when it calls findLastSeparator().

So instead of converting the parent dir path from Utf8 to Utf16 multiple
times, store the dir path as a QString once in the constructor.

Use QStringDecoder to convert the dirent->d_name to Utf16 and check the
decoder's hasError(); which as Thiago pointed out, is more efficient
than using isValidUtf8(), throwing away the results, then converting to
unicode anyway later on in QDirIteratorPrivate::advance().

(Ironically) `QFileSystemEntry::NativePath nativePath` is still used on
Windows.

Change-Id: Icd2b130103640b502862d210d64926b99c499a01
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

1 files changed, 7 insertions, 2 deletions

diff --git a/src/corelib/io/qfilesystemiterator_p.h b/src/corelib/io/qfilesystemiterator_p.h
index 6638016a41..5687da115e 100644
--- a/src/corelib/io/qfilesystemiterator_p.h
+++ b/src/corelib/io/qfilesystemiterator_p.h
@@ -26,6 +26,10 @@
 #include <QtCore/private/qfilesystementry_p.h>
 #include <QtCore/private/qfilesystemmetadata_p.h>
 
+#if !defined(Q_OS_WIN)
+#include <private/qstringconverter_p.h>
+#endif
+
 #include <memory>
 
 QT_BEGIN_NAMESPACE
@@ -39,11 +43,11 @@ public:
     bool advance(QFileSystemEntry &fileEntry, QFileSystemMetaData &metaData);
 
 private:
-    QFileSystemEntry::NativePath nativePath;
+    QString dirPath;
 
     // Platform-specific data
 #if defined(Q_OS_WIN)
-    QString dirPath;
+    QFileSystemEntry::NativePath nativePath;
     HANDLE findFileHandle;
     QStringList uncShares;
     bool uncFallback;
@@ -58,6 +62,7 @@ private:
 
     QT_DIRENT *dirEntry = nullptr;
     int lastError = 0;
+    QStringDecoder toUtf16;
 #endif
 
     Q_DISABLE_COPY_MOVE(QFileSystemIterator)