fix(io): recreate a missing folder on put back and rename kept-both moves

io/localfilesystem.cpp

@@ -337,6 +337,16 @@ static void mergeStaged(int source, int target, const QString &path, OperationCo
     });
 }
 
+// "name (n).ext", the name an item kept beside an existing one takes.
+static QByteArray keptName(const QString &destination, int suffix)
+{
+    const QFileInfo info(destination);
+    const QString extension =
+            info.isDir() || info.suffix().isEmpty() ? QString() : '.' + info.suffix();
+    const QString base = extension.isEmpty() ? info.fileName() : info.completeBaseName();
+    return native(base + QString(" (%1)").arg(suffix) + extension);
+}
+
 static QString publish(int parent, const QByteArray &temporary, const QString &source,
                        const QString &destination, ConflictPolicy policy, OperationContext &ctx)
 {
@@ -388,11 +398,7 @@ static QString publish(int parent, const QByteArray &temporary, const QString &s
             return destination;
         }
 
-        const QFileInfo info(destination);
-        const QString extension =
-                info.isDir() || info.suffix().isEmpty() ? QString() : '.' + info.suffix();
-        const QString base = extension.isEmpty() ? info.fileName() : info.completeBaseName();
-        name = native(base + QString(" (%1)").arg(suffix++) + extension);
+        name = keptName(destination, suffix++);
     }
 }
 
@@ -477,6 +483,18 @@ QString LocalFileSystem::move(const QString &source, const QString &destination,
     if (code == EEXIST && policy == ConflictPolicy::Fail)
         throw Failure(code, destination);
 
+    if (code == EEXIST && policy == ConflictPolicy::KeepBoth) {
+        for (int suffix = 1;; ++suffix) {
+            const QByteArray name = keptName(destination, suffix);
+            if (::syscall(SYS_renameat2, input.fd.value, input.name.constData(), output.fd.value,
+                          name.constData(), RENAME_NOREPLACE)
+                == 0)
+                return QFileInfo(destination).absolutePath() + '/' + QFile::decodeName(name);
+            if (errno != EEXIST)
+                break;
+        }
+    }
+
     if (code == EEXIST && policy == ConflictPolicy::Replace) {
         if (::renameat(input.fd.value, input.name, output.fd.value, output.name) == 0)
             return destination;

io/tests/tst_io.cpp

@@ -218,6 +218,13 @@ private slots:
                  dir.filePath("target (1).txt"));
         QCOMPARE(readFile(dir.filePath("target (1).txt")), QByteArray("new"));
 
+        auto moved = dir.filePath("moved.txt");
+        writeFile(moved, "moved");
+        QCOMPARE(LocalFileSystem::move(moved, target, ConflictPolicy::KeepBoth, ctx),
+                 dir.filePath("target (2).txt"));
+        QCOMPARE(readFile(dir.filePath("target (2).txt")), QByteArray("moved"));
+        QVERIFY(!QFileInfo::exists(moved));
+
         QCOMPARE(LocalFileSystem::copy(source, target, ConflictPolicy::Replace, ctx), target);
         QCOMPARE(readFile(target), QByteArray("new"));
 
@@ -564,6 +571,20 @@ private slots:
         QVERIFY(QDir(FileSystemUrl::trashRoot() + "/info").entryList(QDir::Files).isEmpty());
     }
 
+    void restoreRecreatesFolder()
+    {
+        QTemporaryDir dir;
+        const auto path = dir.filePath("gone/inner/file");
+        QVERIFY(QDir().mkpath(dir.filePath("gone/inner")));
+        writeFile(path);
+
+        OperationContext ctx;
+        const auto trashed = LocalFileSystem::trash(local(path), ctx);
+        QVERIFY(QDir(dir.filePath("gone")).removeRecursively());
+        QCOMPARE(LocalFileSystem::restore(trashed, ConflictPolicy::Fail, ctx), local(path));
+        QVERIFY(QFileInfo::exists(path));
+    }
+
     void malformedTrashInfo()
     {
         QTemporaryDir dir;

io/trash.cpp

@@ -3,6 +3,8 @@
 #include "trashdirectory_p.h"
 
 #include <QDateTime>
+#include <QDir>
+#include <QFileInfo>
 #include <QUuid>
 
 #include <optional>
@@ -263,6 +265,11 @@ QUrl LocalFileSystem::restore(const QUrl &url, ConflictPolicy policy, OperationC
     if (details.path.isEmpty())
         throw Failure(EINVAL, info);
 
+    // A folder deleted since the item was trashed is made again.
+    const QString parent = QFileInfo(details.path).absolutePath();
+    if (!QDir().mkpath(parent))
+        throw Failure(errno ? errno : EIO, parent);
+
     auto result = move(FileSystemUrl(url).localPath(), details.path, policy, ctx);
     if (result.isEmpty())
         return {};