qt: Use temporary .part file names when creating archives

* lang/qt/src/util.h, lang/qt/src/util.cpp (class PartialFileGuard):
New.
* lang/qt/src/util.cpp (getRandomCharacters, createPartFileName): New.
* lang/qt/src/qgpgmeencryptarchivejob.cpp (encrypt_to_filename): Use
PartialFileGuard.
* lang/qt/src/qgpgmesignarchivejob.cpp (sign_to_filename): Ditto.
* lang/qt/src/qgpgmesignencryptarchivejob.cpp
(sign_encrypt_to_filename): Ditto.
--

When creating signed and/or encrypted archives, gpgtar now writes the
result to a temporary file name. On success, the archive is renamed to
the final file name. Otherwise, the (partially written) temporary file
is removed (if possible).

GnuPG-bug-id: 6721

1 files changed, 13 insertions, 5 deletions

diff --git a/lang/qt/src/qgpgmesignencryptarchivejob.cpp b/lang/qt/src/qgpgmesignencryptarchivejob.cpp
index 3403ad57..c156bcba 100644
--- a/lang/qt/src/qgpgmesignencryptarchivejob.cpp
+++ b/lang/qt/src/qgpgmesignencryptarchivejob.cpp
@@ -147,19 +147,27 @@ static QGpgMESignEncryptArchiveJob::result_type sign_encrypt_to_filename(Context
                                                                          Context::EncryptionFlags encryptionFlags,
                                                                          const QString &baseDirectory)
 {
+    PartialFileGuard partFileGuard{outputFileName};
+    if (partFileGuard.tempFileName().isEmpty()) {
+        return std::make_tuple(SigningResult{Error::fromCode(GPG_ERR_EEXIST)},
+                               EncryptionResult{Error::fromCode(GPG_ERR_EEXIST)},
+                               QString{},
+                               Error{});
+    }
+
     Data outdata;
 #ifdef Q_OS_WIN
-    outdata.setFileName(outputFileName.toUtf8().constData());
+    outdata.setFileName(partFileGuard.tempFileName().toUtf8().constData());
 #else
-    outdata.setFileName(QFile::encodeName(outputFileName).constData());
+    outdata.setFileName(QFile::encodeName(partFileGuard.tempFileName()).constData());
 #endif
 
     const auto result = sign_encrypt(ctx, signers, recipients, paths, outdata, encryptionFlags, baseDirectory);
     const auto &signingResult = std::get<0>(result);
     const auto &encryptionResult = std::get<1>(result);
-    if (signingResult.error().code() || encryptionResult.error().code()) {
-        // ensure that the output file is removed if the operation was canceled or failed
-        removeFile(outputFileName);
+    if (!signingResult.error().code() && !encryptionResult.error().code()) {
+        // the operation succeeded -> save the result under the requested file name
+        partFileGuard.commit();
     }
 
     return result;