Copy directory using Qt

Question

I want to copy a directory from one drive to another drive. My selected directory contains many sub directories and files.

How can I implement the same using Qt?

petch · Answer 1 · 2013-08-07T00:25:14.623

24

void copyPath(QString src, QString dst)
{
    QDir dir(src);
    if (! dir.exists())
        return;

    foreach (QString d, dir.entryList(QDir::Dirs | QDir::NoDotAndDotDot)) {
        QString dst_path = dst + QDir::separator() + d;
        dir.mkpath(dst_path);
        copyPath(src+ QDir::separator() + d, dst_path);
    }

    foreach (QString f, dir.entryList(QDir::Files)) {
        QFile::copy(src + QDir::separator() + f, dst + QDir::separator() + f);
    }
}

edited Aug 07 '13 at 00:25

answered Aug 07 '13 at 00:15

petch

399
2
4

I don't know if it's my rig, or this code in Qt 5.6, but this code seems to hang. It's doing directory-copying, but never finishing. Weird. – kayleeFrye_onDeck Apr 06 '16 at 19:10
Hm, yep. First copy operation works, and then subsequent copies are going bananas. Make a dir, then copy that dir into a subdir. First works, second, bang, dead. – kayleeFrye_onDeck Apr 06 '16 at 19:18

score 13 · Answer 2 · answered Mar 29 '10 at 08:50

Manually, you can do the next things:

1). with func below you generate folders/files list (recursively) - the destination files.

static void recurseAddDir(QDir d, QStringList & list) {

    QStringList qsl = d.entryList(QDir::NoDotAndDotDot | QDir::Dirs | QDir::Files);

    foreach (QString file, qsl) {

        QFileInfo finfo(QString("%1/%2").arg(d.path()).arg(file));

        if (finfo.isSymLink())
            return;

        if (finfo.isDir()) {

            QString dirname = finfo.fileName();
            QDir sd(finfo.filePath());

            recurseAddDir(sd, list);

        } else
            list << QDir::toNativeSeparators(finfo.filePath());
    }
}

2). then you may to start copying files from destination list to the new source directory like that:

for (int i = 0; i < gtdStringList.count(); i++) {

    progressDialog.setValue(i);
    progressDialog.setLabelText(tr("%1 Coping file number %2 of %3 ")
        .arg((conf->isConsole) ? tr("Making copy of the Alta-GTD\n") : "")
        .arg(i + 1)
        .arg(gtdStringList.count()));

    qApp->processEvents(QEventLoop::ExcludeUserInputEvents);

    if (progressDialog.wasCanceled()) {

        // removing tmp files/folders
        rmDirectoryRecursive(tmpFolder);
        rmDirectoryRecursive(tmpFolderPlus);
        setEnableGUI(true);
        return;
    }

    // coping
    if (!QFile::copy(gtdStringList.at(i), tmpStringList.at(i))) {

        if (warningFlag) {

            QMessageBox box(this);
            QString name = tr("Question");
            QString file1 = getShortName(gtdStringList.at(i), QString("\\...\\"));
            QString file2 = getShortName(tmpStringList.at(i), QString("\\...\\"));
            QString text = tr("Cannot copy <b>%1</b> <p>to <b>%2</b>"   \
               "<p>This file will be ignored, just press <b>Yes</b> button" \
               "<p>Press <b>YesToAll</b> button to ignore other warnings automatically..."  \
               "<p>Or press <b>Abort</b> to cancel operation").arg(file1).arg(file2);

            box.setModal(true);
            box.setWindowTitle(name);
            box.setText(QString::fromLatin1("%1").arg(text));
            box.setIcon(QMessageBox::Question);
            box.setStandardButtons(QMessageBox::YesToAll | QMessageBox::Yes | QMessageBox::Abort);

            switch (box.exec()) {                   
                case (QMessageBox::YesToAll):
                    warningFlag = false;
                    break;
                case (QMessageBox::Yes):
                    break;
                case (QMessageBox::Abort):
                    rmDirectoryRecursive(tmpFolder);
                    rmDirectoryRecursive(tmpFolderPlus);
                    setEnableGUI(true);
                    return;
            }
        }
    }
}

And that's all. Good luck!

i've tried posting my correction as an edit but nobody seems to understand it, so i'll post it here. using `QString("%1/%2").arg(d.path()).arg(file)` is generally not a good idea seeing as '%1' or '%2' can be found (in most filesystems) in a file or path name. take this path created by cygwin as an example `c:\cyg\ftp%3a%2f%2fcygwin.mirrorcatalogs.com%2fcygwin%2f`. — vikki, May 18 '12 at 18:35
lets say this is what is held in `d.path()` and `file` has `text.txt`. '%1' will be replaced by `d.path()` to form `c:\cyg\ftp%3a%2f%2fcygwin.mirrorcatalogs.com%2fcygwin%2f/%2`. finally you'll have `c:\cyg\ftp%3atext.txtftext.txtfcygwin.mirrorcatalogs.comtext.txtfcygwintext.txtf/text.txt`. a better option is `d.path().append('/').append(file)` — vikki, May 18 '12 at 18:37
If you use append it return a reference and if you use it again in other place it may change.Be careful if desided — Shihe Zhang, Dec 16 '15 at 03:31
The safe alternative is `QString("%1/%2").arg(d.path(), file)` - but it's better to compose pathnames using `d.filePath(file)` which will use the platform's directory separator portably. You still need the `QString::arg(QString, QString)` for composing the message box text, of course. — Toby Speight, Jul 20 '17 at 12:55

score 7 · Answer 3 · answered Mar 31 '11 at 13:01

I wanted something similar, and was googling (in vain), so this is where I've got to:

static bool cpDir(const QString &srcPath, const QString &dstPath)
{
    rmDir(dstPath);
    QDir parentDstDir(QFileInfo(dstPath).path());
    if (!parentDstDir.mkdir(QFileInfo(dstPath).fileName()))
        return false;

    QDir srcDir(srcPath);
    foreach(const QFileInfo &info, srcDir.entryInfoList(QDir::Dirs | QDir::Files | QDir::NoDotAndDotDot)) {
        QString srcItemPath = srcPath + "/" + info.fileName();
        QString dstItemPath = dstPath + "/" + info.fileName();
        if (info.isDir()) {
            if (!cpDir(srcItemPath, dstItemPath)) {
                return false;
            }
        } else if (info.isFile()) {
            if (!QFile::copy(srcItemPath, dstItemPath)) {
                return false;
            }
        } else {
            qDebug() << "Unhandled item" << info.filePath() << "in cpDir";
        }
    }
    return true;
}

It uses an rmDir function that looks pretty similar:

static bool rmDir(const QString &dirPath)
{
    QDir dir(dirPath);
    if (!dir.exists())
        return true;
    foreach(const QFileInfo &info, dir.entryInfoList(QDir::Dirs | QDir::Files | QDir::NoDotAndDotDot)) {
        if (info.isDir()) {
            if (!rmDir(info.filePath()))
                return false;
        } else {
            if (!dir.remove(info.fileName()))
                return false;
        }
    }
    QDir parentDir(QFileInfo(dirPath).path());
    return parentDir.rmdir(QFileInfo(dirPath).fileName());
}

This doesn't handle links and special files, btw.

score 6 · Answer 4 · edited Mar 29 '10 at 09:21

6

The hard way. Copy every file individually.

Use QDir::entryList() to iterate over the content of a directory
Use QDir::cd() and QDir::cdUp() to go in and out of directories
Use QDir::mkdir() and QDir::mkpath() to create the new folders tree
and finally, use QFile::copy() to copy the actual files

edited Mar 29 '10 at 09:21

Peter Mortensen

28,342
21
95
123

answered Mar 29 '10 at 08:22

shoosh

70,450
50
199
310

score 2 · Answer 5 · edited May 23 '17 at 12:02

This is basically petch's answer with a slight change due to it breaking for me in Qt 5.6 (this is the top question hit), so all credit goes to petch.

function

bool copyPath(QString sourceDir, QString destinationDir, bool overWriteDirectory)
{
    QDir originDirectory(sourceDir);

    if (! originDirectory.exists())
    {
        return false;
    }

    QDir destinationDirectory(destinationDir);

    if(destinationDirectory.exists() && !overWriteDirectory)
    {
        return false;
    }
    else if(destinationDirectory.exists() && overWriteDirectory)
    {
        destinationDirectory.removeRecursively();
    }

    originDirectory.mkpath(destinationDir);

    foreach (QString directoryName, originDirectory.entryList(QDir::Dirs | \
                                                              QDir::NoDotAndDotDot))
    {
        QString destinationPath = destinationDir + "/" + directoryName;
        originDirectory.mkpath(destinationPath);
        copyPath(sourceDir + "/" + directoryName, destinationPath, overWriteDirectory);
    }

    foreach (QString fileName, originDirectory.entryList(QDir::Files))
    {
        QFile::copy(sourceDir + "/" + fileName, destinationDir + "/" + fileName);
    }

    /*! Possible race-condition mitigation? */
    QDir finalDestination(destinationDir);
    finalDestination.refresh();

    if(finalDestination.exists())
    {
        return true;
    }

    return false;
}

Use:

/*! Overwrite existing directories. */
bool directoryCopied = copyPath(sourceDirectory, destinationDirectory, true);

/*! Do not overwrite existing directories. */
bool directoryCopied = copyPath(sourceDirectory, destinationDirectory, false);

What's different and why? – Toby Speight Jul 20 '17 at 12:57 — Toby Speight, Jul 20 '17 at 12:57

score 2 · Answer 6 · edited Jul 23 '16 at 18:19

Try this:

bool copyDirectoryFiles(const QString &fromDir, const QString &toDir, bool coverFileIfExist)
{
    QDir sourceDir(fromDir);
    QDir targetDir(toDir);
    if(!targetDir.exists()){    /* if directory don't exists, build it */
        if(!targetDir.mkdir(targetDir.absolutePath()))
            return false;
    }

    QFileInfoList fileInfoList = sourceDir.entryInfoList();
    foreach(QFileInfo fileInfo, fileInfoList){
        if(fileInfo.fileName() == "." || fileInfo.fileName() == "..")
            continue;

        if(fileInfo.isDir()){    /* if it is directory, copy recursively*/
            if(!copyDirectoryFiles(fileInfo.filePath(),  
                targetDir.filePath(fileInfo.fileName()), 
                coverFileIfExist)) 
                return false;
        }
        else{            /* if coverFileIfExist == true, remove old file first */
            if(coverFileIfExist && targetDir.exists(fileInfo.fileName())){
                targetDir.remove(fileInfo.fileName());
            }

            // files copy
            if(!QFile::copy(fileInfo.filePath(),  
                targetDir.filePath(fileInfo.fileName()))){ 
                    return false;
            }
        }
    }
    return true;
}

Thank you for this code snippet, which may provide some immediate help. A proper explanation [would greatly improve](//meta.stackexchange.com/q/114762) its educational value by showing *why* this is a good solution to the problem, and would make it more useful to future readers with similar, but not identical, questions. Please [edit] your answer to add explanation, and give an indication of what limitations and assumptions apply. — Toby Speight, Jul 20 '17 at 12:57

benlau · Answer 7 · 2017-03-01T13:11:47.113

I have made a library to manipulate files by a shell command style API. It supports a recursively copy of files and handled several more conditions.

https://github.com/benlau/qtshell#cp

Example

cp("-a", ":/*", "/target"); // copy all files from qrc resource to target path recursively

cp("tmp.txt", "/tmp");

cp("*.txt", "/tmp");

cp("/tmp/123.txt", "456.txt");

cp("-va","src/*", "/tmp");

cp("-a", ":resource","/target");

score 0 · Answer 8 · answered Mar 18 '21 at 09:59

Since I had some trouble with App-Bundles on macOS, here's a solution with QDirIterator

void copyAndReplaceFolderContents(const QString &fromDir, const QString &toDir, bool copyAndRemove = false) {
QDirIterator it(fromDir, QDirIterator::Subdirectories);
QDir dir(fromDir);
const int absSourcePathLength = dir.absoluteFilePath(fromDir).length();

while (it.hasNext()){
    it.next();
    const auto fileInfo = it.fileInfo();
    if(!fileInfo.isHidden()) { //filters dot and dotdot
        const QString subPathStructure = fileInfo.absoluteFilePath().mid(absSourcePathLength);
        const QString constructedAbsolutePath = toDir + subPathStructure;
        
        if(fileInfo.isDir()){
            //Create directory in target folder
            dir.mkpath(constructedAbsolutePath);
        } else if(fileInfo.isFile()) {
            //Copy File to target directory

            //Remove file at target location, if it exists. Otherwise QFile::copy will fail
            QFile::remove(constructedAbsolutePath);
            QFile::copy(fileInfo.absoluteFilePath(), constructedAbsolutePath);
        }
    }
}

if(copyAndRemove)
    dir.removeRecursively();

}

Copy directory using Qt

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