Standardize on unique_ptr to hold QAbstractFileEngine

This will make it possible to return it from functions in an owner,
as exemplified in the QFileInfoPrivate ctor, unlike QScopedPointer,
which lacks move special member functions.

Change-Id: I179ffa4f656e1b83c23e0f67d1542834460ff382
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>

src/corelib/io/qdir.cpp

@@ -153,7 +153,7 @@ QDirPrivate::QDirPrivate(const QDirPrivate &copy)
 
 bool QDirPrivate::exists() const
 {
-    if (fileEngine.isNull()) {
+    if (!fileEngine) {
         QFileSystemEngine::fillMetaData(dirEntry, metaData,
                 QFileSystemMetaData::ExistsAttribute | QFileSystemMetaData::DirectoryType); // always stat
         return metaData.exists() && metaData.isDirectory();
@@ -226,7 +226,7 @@ inline void QDirPrivate::resolveAbsoluteEntry() const
         return;
 
     QString absoluteName;
-    if (fileEngine.isNull()) {
+    if (!fileEngine) {
         if (!dirEntry.isRelative() && dirEntry.isClean()) {
             absoluteDirEntry = dirEntry;
             return;
@@ -693,7 +693,7 @@ QString QDir::absolutePath() const
 QString QDir::canonicalPath() const
 {
     const QDirPrivate* d = d_ptr.constData();
-    if (d->fileEngine.isNull()) {
+    if (!d->fileEngine) {
         QFileSystemEntry answer = QFileSystemEngine::canonicalName(d->dirEntry, d->metaData);
         return answer.filePath();
     }
@@ -1502,7 +1502,7 @@ bool QDir::mkdir(const QString &dirName) const
     }
 
     QString fn = filePath(dirName);
-    if (d->fileEngine.isNull())
+    if (!d->fileEngine)
         return QFileSystemEngine::createDirectory(QFileSystemEntry(fn), false);
     return d->fileEngine->mkdir(fn, false);
 }
@@ -1526,7 +1526,7 @@ bool QDir::rmdir(const QString &dirName) const
     }
 
     QString fn = filePath(dirName);
-    if (d->fileEngine.isNull())
+    if (!d->fileEngine)
         return QFileSystemEngine::removeDirectory(QFileSystemEntry(fn), false);
 
     return d->fileEngine->rmdir(fn, false);
@@ -1554,7 +1554,7 @@ bool QDir::mkpath(const QString &dirPath) const
     }
 
     QString fn = filePath(dirPath);
-    if (d->fileEngine.isNull())
+    if (!d->fileEngine)
         return QFileSystemEngine::createDirectory(QFileSystemEntry(fn), true);
     return d->fileEngine->mkdir(fn, true);
 }
@@ -1580,7 +1580,7 @@ bool QDir::rmpath(const QString &dirPath) const
     }
 
     QString fn = filePath(dirPath);
-    if (d->fileEngine.isNull())
+    if (!d->fileEngine)
         return QFileSystemEngine::removeDirectory(QFileSystemEntry(fn), true);
     return d->fileEngine->rmdir(fn, true);
 }
@@ -1653,7 +1653,7 @@ bool QDir::isReadable() const
 {
     const QDirPrivate* d = d_ptr.constData();
 
-    if (d->fileEngine.isNull()) {
+    if (!d->fileEngine) {
         if (!d->metaData.hasFlags(QFileSystemMetaData::UserReadPermission))
             QFileSystemEngine::fillMetaData(d->dirEntry, d->metaData, QFileSystemMetaData::UserReadPermission);
 
@@ -1698,7 +1698,7 @@ bool QDir::exists() const
 */
 bool QDir::isRoot() const
 {
-    if (d_ptr->fileEngine.isNull())
+    if (!d_ptr->fileEngine)
         return d_ptr->dirEntry.isRoot();
     return d_ptr->fileEngine->fileFlags(QAbstractFileEngine::FlagsMask) & QAbstractFileEngine::RootFlag;
 }
@@ -1730,7 +1730,7 @@ bool QDir::isRoot() const
 */
 bool QDir::isRelative() const
 {
-    if (d_ptr->fileEngine.isNull())
+    if (!d_ptr->fileEngine)
         return d_ptr->dirEntry.isRelative();
     return d_ptr->fileEngine->isRelativePath();
 }
@@ -1747,7 +1747,7 @@ bool QDir::makeAbsolute()
 {
     const QDirPrivate *d = d_ptr.constData();
     QScopedPointer<QDirPrivate> dir;
-    if (!d->fileEngine.isNull()) {
+    if (!!d->fileEngine) {
         QString absolutePath = d->fileEngine->fileName(QAbstractFileEngine::AbsoluteName);
         if (QDir::isRelativePath(absolutePath))
             return false;
@@ -1780,8 +1780,8 @@ bool QDir::operator==(const QDir &dir) const
     if (d == other)
         return true;
     Qt::CaseSensitivity sensitive;
-    if (d->fileEngine.isNull() || other->fileEngine.isNull()) {
+    if (!d->fileEngine || !other->fileEngine) {
-        if (d->fileEngine.data() != other->fileEngine.data()) // one is native, the other is a custom file-engine
+        if (d->fileEngine.get() != other->fileEngine.get()) // one is native, the other is a custom file-engine
             return false;
 
         sensitive = QFileSystemEngine::isCaseSensitive() ? Qt::CaseSensitive : Qt::CaseInsensitive;

src/corelib/io/qdir_p.h

@@ -54,6 +54,8 @@
 #include "qfilesystementry_p.h"
 #include "qfilesystemmetadata_p.h"
 
+#include <memory>
+
 QT_BEGIN_NAMESPACE
 
 class QDirPrivate : public QSharedData
@@ -98,7 +100,7 @@ public:
     QDir::SortFlags sort;
     QDir::Filters filters;
 
-    QScopedPointer<QAbstractFileEngine> fileEngine;
+    std::unique_ptr<QAbstractFileEngine> fileEngine;
 
     QFileSystemEntry dirEntry;
     mutable QFileSystemEntry absoluteDirEntry;

src/corelib/io/qdiriterator.cpp

@@ -107,6 +107,8 @@
 #include <QtCore/private/qfilesystemengine_p.h>
 #include <QtCore/private/qfileinfo_p.h>
 
+#include <memory>
+
 QT_BEGIN_NAMESPACE
 
 template <class Iterator>
@@ -132,7 +134,7 @@ public:
     void checkAndPushDirectory(const QFileInfo &);
     bool matchesFilters(const QString &fileName, const QFileInfo &fi) const;
 
-    QScopedPointer<QAbstractFileEngine> engine;
+    std::unique_ptr<QAbstractFileEngine> engine;
 
     QFileSystemEntry dirEntry;
     const QStringList nameFilters;
@@ -435,7 +437,7 @@ bool QDirIteratorPrivate::matchesFilters(const QString &fileName, const QFileInf
 QDirIterator::QDirIterator(const QDir &dir, IteratorFlags flags)
 {
     const QDirPrivate *other = dir.d_ptr.constData();
-    d.reset(new QDirIteratorPrivate(other->dirEntry, other->nameFilters, other->filters, flags, !other->fileEngine.isNull()));
+    d.reset(new QDirIteratorPrivate(other->dirEntry, other->nameFilters, other->filters, flags, bool(other->fileEngine)));
 }
 
 /*!

src/corelib/io/qfileinfo.cpp

@@ -707,11 +707,11 @@ bool QFileInfo::exists(const QString &file)
         return false;
     QFileSystemEntry entry(file);
     QFileSystemMetaData data;
-    QAbstractFileEngine *engine =
+    std::unique_ptr<QAbstractFileEngine> engine
-        QFileSystemEngine::resolveEntryAndCreateLegacyEngine(entry, data);
+        {QFileSystemEngine::resolveEntryAndCreateLegacyEngine(entry, data)};
     // Expensive fallback to non-QFileSystemEngine implementation
     if (engine)
-        return QFileInfo(new QFileInfoPrivate(entry, data, engine)).exists();
+        return QFileInfo(new QFileInfoPrivate(entry, data, std::move(engine))).exists();
 
     QFileSystemEngine::fillMetaData(entry, data, QFileSystemMetaData::ExistsAttribute);
     return data.exists();

src/corelib/io/qfileinfo_p.h

@@ -61,6 +61,8 @@
 #include <QtCore/private/qfilesystementry_p.h>
 #include <QtCore/private/qfilesystemmetadata_p.h>
 
+#include <memory>
+
 QT_BEGIN_NAMESPACE
 
 class QFileInfoPrivate : public QSharedData
@@ -126,10 +128,10 @@ public:
             metaData = QFileSystemMetaData();
     }
 
-    inline QFileInfoPrivate(const QFileSystemEntry &file, const QFileSystemMetaData &data, QAbstractFileEngine *engine)
+    inline QFileInfoPrivate(const QFileSystemEntry &file, const QFileSystemMetaData &data, std::unique_ptr<QAbstractFileEngine> engine)
         : fileEntry(file),
         metaData(data),
-        fileEngine(engine),
+        fileEngine{std::move(engine)},
         cachedFlags(0),
 #ifndef QT_NO_FSFILEENGINE
         isDefaultConstructed(false),
@@ -163,7 +165,7 @@ public:
     QFileSystemEntry fileEntry;
     mutable QFileSystemMetaData metaData;
 
-    QScopedPointer<QAbstractFileEngine> const fileEngine;
+    std::unique_ptr<QAbstractFileEngine> const fileEngine;
 
     mutable QString fileNames[QAbstractFileEngine::NFileNames];
     mutable QString fileOwners[2];  // QAbstractFileEngine::FileOwner: OwnerUser and OwnerGroup