QFSFileEngine: update d->fileEntry after a successful rename

Otherwise member methods such as size() could return incorrect info.

Add setFileEntry(QFileSystemEntry &&); to reuse a QFileSystemEntry if we
have already constructed one.

As a result of this, a QTemporaryFileEngine::setFileName() call has
become redundant and can be removed; the code it executed is already
taken care of:
- QFSFileEngine::close(): already called by QTFEngine::rename() a couple
  of lines above
- QFSFileEngine::setFileName(): QTFEngine::rename() calls
  QFSFileEngine::rename() which in turn updates the `fileEntry`

This commit is covered by tst_QTemporaryFile::rename(), i.e. if
QFSFileEngine::rename() didn't update the fileEntry, that test would
fail.

Change-Id: I312f35cf7fdf9b1a8cd0bce5e98ba7a48cf9426e
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@gmx.de>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

src/corelib/io/qfsfileengine.cpp

@@ -990,6 +990,17 @@ bool QFSFileEngine::remove()
     return ret;
 }
 
+/*
+    An alternative to setFileName() when you have already constructed
+    a QFileSystemEntry.
+*/
+void QFSFileEngine::setFileEntry(QFileSystemEntry &&entry)
+{
+    Q_D(QFSFileEngine);
+    d->init();
+    d->fileEntry = std::move(entry);
+}
+
 bool QFSFileEngine::rename_helper(const QString &newName, RenameMode mode)
 {
     Q_D(QFSFileEngine);
@@ -997,10 +1008,14 @@ bool QFSFileEngine::rename_helper(const QString &newName, RenameMode mode)
     auto func = mode == Rename ? QFileSystemEngine::renameFile
                                : QFileSystemEngine::renameOverwriteFile;
     QSystemError error;
-    const bool ret = func(d->fileEntry, QFileSystemEntry(newName), error);
-    if (!ret)
+    auto newEntry = QFileSystemEntry(newName);
+    const bool ret = func(d->fileEntry, newEntry, error);
+    if (!ret) {
         setError(QFile::RenameError, error.toString());
-    return ret;
+        return false;
+    }
+    setFileEntry(std::move(newEntry));
+    return true;
 }
 
 /*!

src/corelib/io/qfsfileengine_p.h

@@ -83,6 +83,7 @@ public:
     bool setFileTime(const QDateTime &newDate, QFile::FileTime time) override;
     QDateTime fileTime(QFile::FileTime time) const override;
     void setFileName(const QString &file) override;
+    void setFileEntry(QFileSystemEntry &&entry);
     int handle() const override;
 
 #ifndef QT_NO_FILESYSTEMITERATOR
@@ -160,7 +161,7 @@ public:
     bool isSequentialFdFh() const;
 #endif
 #ifdef Q_OS_WIN
-    bool nativeRenameOverwrite(const QString &newName);
+    bool nativeRenameOverwrite(const QFileSystemEntry &newEntry);
 #endif
 
     uchar *map(qint64 offset, qint64 size, QFile::MemoryMapFlags flags);

src/corelib/io/qfsfileengine_win.cpp

@@ -396,11 +396,10 @@ bool QFSFileEnginePrivate::nativeIsSequential() const
             || (fileType == FILE_TYPE_PIPE);
 }
 
-bool QFSFileEnginePrivate::nativeRenameOverwrite(const QString &newName)
+bool QFSFileEnginePrivate::nativeRenameOverwrite(const QFileSystemEntry &newEntry)
 {
     if (fileHandle == INVALID_HANDLE_VALUE)
         return false;
-    QFileSystemEntry newEntry(newName, QFileSystemEntry::FromInternalPath());
     const QString newFilePath = newEntry.nativeFilePath();
     const size_t nameByteLength = newFilePath.length() * sizeof(wchar_t);
     if (nameByteLength + sizeof(wchar_t) > std::numeric_limits<DWORD>::max())

src/corelib/io/qtemporaryfile.cpp

@@ -393,8 +393,13 @@ bool QTemporaryFileEngine::renameOverwrite(const QString &newName)
     }
 #ifdef Q_OS_WIN
     if (flags & Win32NonShared) {
-        bool ok = d_func()->nativeRenameOverwrite(newName);
+        QFileSystemEntry newEntry(newName, QFileSystemEntry::FromInternalPath());
+        bool ok = d_func()->nativeRenameOverwrite(newEntry);
         QFSFileEngine::close();
+        if (ok) {
+            // Match what QFSFileEngine::renameOverwrite() does
+            setFileEntry(std::move(newEntry));
+        }
         return ok;
     }
 #endif
@@ -868,7 +873,6 @@ bool QTemporaryFile::rename(const QString &newName)
         if (tef->rename(newName)) {
             unsetError();
             // engine was able to handle the new name so we just reset it
-            tef->setFileName(newName);
             d->fileName = newName;
             return true;
         }