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moveToTrash/Unix: use the file's inode number as collision avoidance

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Instead of a sequential and thus predictable counter. This improves the
performance of when you keep creating and trashing the same file base
name. The previous algorithm would try all occurrences from 0 to however
many trashings have happened.

This could have been any random number, but the source file's inode is
"random" enough for us.

strace of the second file's trashing:

openat(AT_FDCWD, "/home/tjmaciei/.qttest/share/Trash/info/tst_qfile.moveToTrashOpenFile.vLwfNe.trashinfo", O_RDWR|O_CREAT|O_EXCL|O_CLOEXEC, 0666) = -1 EEXIST (File exists)
newfstatat(AT_FDCWD, "/home/tjmaciei/tst_qfile.moveToTrashOpenFile.vLwfNe", {st_mode=S_IFREG|0644, st_size=16, ...}, 0) = 0
openat(AT_FDCWD, "/home/tjmaciei/.qttest/share/Trash/info/tst_qfile.moveToTrashOpenFile.vLwfNe-23527891.trashinfo", O_RDWR|O_CREAT|O_EXCL|O_CLOEXEC, 0666) = 4
newfstatat(AT_FDCWD, "/etc/localtime", {st_mode=S_IFREG|0644, st_size=2852, ...}, 0) = 0
write(4, "[Trash Info]\nPath=/home/tjmaciei"..., 103) = 103
renameat2(AT_FDCWD, "/home/tjmaciei/tst_qfile.moveToTrashOpenFile.vLwfNe", AT_FDCWD, "/home/tjmaciei/.qttest/share/Trash/files/tst_qfile.moveToTrashOpenFile.vLwfNe-23527891", RENAME_NOREPLACE) = 0
close(4)                                = 0

Change-Id: I9d43e5b91eb142d6945cfffd1786d73459c2eb3d
Reviewed-by: Ahmad Samir <a.samirh78@gmail.com>
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>
This commit is contained in:
Thiago Macieira 2023-09-20 23:48:49 -07:00
parent 77c661b275
commit 25b1990784
1 changed files with 15 additions and 4 deletions
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19
src/corelib/io/qfilesystemengine_unix.cpp
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@ -1418,14 +1418,25 @@ bool QFileSystemEngine::moveFileToTrash(const QFileSystemEntry &source,
*/
QString uniqueTrashedName = u'/' + sourcePath.fileName();
if (!op.tryCreateInfoFile(uniqueTrashedName, error) && error.errorCode == EEXIST) {
for (int counter = 0; op.infoFileFd == -1; ++counter) {
uniqueTrashedName = QString::asprintf("/%ls-%04d", qUtf16Printable(sourcePath.fileName()),
counter);
// we'll use a counter, starting with the file's inode number to avoid
// collisions
qulonglong counter;
if (QT_STATBUF st; Q_LIKELY(QT_STAT(source.nativeFilePath(), &st) == 0)) {
counter = st.st_ino;
} else {
error = QSystemError(errno, QSystemError::StandardLibraryError);
return false;
}
QString uniqueTrashBase = std::move(uniqueTrashedName);
for (;;) {
uniqueTrashedName = QString::asprintf("%ls-%llu", qUtf16Printable(uniqueTrashBase),
counter++);
if (op.tryCreateInfoFile(uniqueTrashedName, error))
break;
if (error.errorCode != EEXIST)
return false;
}
};
}
QByteArray info =