CopyFileEx with progress callback in Qt - c++

Question

Can anybody give me a working example of use CopyFileEx with progress callback in Qt?
I found some scratch and tried to merge it but with no success. I even couldn't pass CopyProgressRoutine function as an argument of CopyFileEx because I couldn't declare pointer to this function.
I'm not so good to port code from other IDEs, so I need help of yours.

Answer 1

The code below is a complete, self-contained example. It works under both Qt 5 and Qt 4, and uses C++11 (e.g. Visual Studio 2015 & newer).
main.cpp
// https://github.com/KubaO/stackoverflown/tree/master/questions/copyfileex-19136936
#include <QtGui>
#include <QtConcurrent>
#if QT_VERSION >= QT_VERSION_CHECK(5,0,0)
#include <QtWidgets>
#endif
#include <windows.h>
#include <comdef.h>
//#define _WIN32_WINNT _WIN32_WINNT_WIN7
static QString toString(HRESULT hr) {
_com_error err{hr};
return QStringLiteral("Error 0x%1: %2").arg((quint32)hr, 8, 16, QLatin1Char('0'))
.arg(err.ErrorMessage());
}
static QString getLastErrorMsg() {
return toString(HRESULT_FROM_WIN32(GetLastError()));
}
static QString progressMessage(ULONGLONG part, ULONGLONG whole) {
return QStringLiteral("Transferred %1 of %2 bytes.")
.arg(part).arg(whole);
}
class Copier : public QObject {
Q_OBJECT
BOOL m_stop;
QMutex m_pauseMutex;
QAtomicInt m_pause;
QWaitCondition m_pauseWait;
QString m_src, m_dst;
ULONGLONG m_lastPart, m_lastWhole;
void newStatus(ULONGLONG part, ULONGLONG whole) {
if (part != m_lastPart || whole != m_lastWhole) {
m_lastPart = part;
m_lastWhole = whole;
emit newStatus(progressMessage(part, whole));
}
}
#if _WIN32_WINNT >= _WIN32_WINNT_WIN8
static COPYFILE2_MESSAGE_ACTION CALLBACK copyProgress2(
const COPYFILE2_MESSAGE *message, PVOID context);
#else
static DWORD CALLBACK copyProgress(
LARGE_INTEGER totalSize, LARGE_INTEGER totalTransferred,
LARGE_INTEGER streamSize, LARGE_INTEGER streamTransferred,
DWORD streamNo, DWORD callbackReason, HANDLE src, HANDLE dst,
LPVOID data);
#endif
public:
Copier(const QString & src, const QString & dst, QObject * parent = nullptr) :
QObject{parent}, m_src{src}, m_dst{dst} {}
Q_SIGNAL void newStatus(const QString &);
Q_SIGNAL void finished();
/// This method is thread-safe
Q_SLOT void copy();
/// This method is thread-safe
Q_SLOT void stop() {
resume();
m_stop = TRUE;
}
/// This method is thread-safe
Q_SLOT void pause() {
m_pause = true;
}
/// This method is thread-safe
Q_SLOT void resume() {
if (m_pause)
m_pauseWait.notify_one();
m_pause = false;
}
~Copier() override { stop(); }
};
#if _WIN32_WINNT >= _WIN32_WINNT_WIN8
void Copier::copy() {
m_lastPart = m_lastWhole = {};
m_stop = FALSE;
m_pause = false;
QtConcurrent::run([this]{
COPYFILE2_EXTENDED_PARAMETERS params{
sizeof(COPYFILE2_EXTENDED_PARAMETERS), 0, &m_stop,
Copier::copyProgress2, this
};
auto rc = CopyFile2((PCWSTR)m_src.utf16(), (PCWSTR)m_dst.utf16(), &params);
if (!SUCCEEDED(rc))
emit newStatus(toString(rc));
emit finished();
});
}
COPYFILE2_MESSAGE_ACTION CALLBACK Copier::copyProgress2(
const COPYFILE2_MESSAGE *message, PVOID context)
{
COPYFILE2_MESSAGE_ACTION action = COPYFILE2_PROGRESS_CONTINUE;
auto self = static_cast<Copier*>(context);
if (message->Type == COPYFILE2_CALLBACK_CHUNK_FINISHED) {
auto &info = message->Info.ChunkFinished;
self->newStatus(info.uliTotalBytesTransferred.QuadPart, info.uliTotalFileSize.QuadPart);
}
else if (message->Type == COPYFILE2_CALLBACK_ERROR) {
auto &info = message->Info.Error;
self->newStatus(info.uliTotalBytesTransferred.QuadPart, info.uliTotalFileSize.QuadPart);
emit self->newStatus(toString(info.hrFailure));
action = COPYFILE2_PROGRESS_CANCEL;
}
if (self->m_pause) {
QMutexLocker lock{&self->m_pauseMutex};
self->m_pauseWait.wait(&self->m_pauseMutex);
}
return action;
}
#else
void Copier::copy() {
m_lastPart = m_lastWhole = {};
m_stop = FALSE;
m_pause = false;
QtConcurrent::run([this]{
auto rc = CopyFileExW((LPCWSTR)m_src.utf16(), (LPCWSTR)m_dst.utf16(),
&copyProgress, this, &m_stop, 0);
if (!rc)
emit newStatus(getLastErrorMsg());
emit finished();
});
}
DWORD CALLBACK Copier::copyProgress(
const LARGE_INTEGER totalSize, const LARGE_INTEGER totalTransferred,
LARGE_INTEGER, LARGE_INTEGER, DWORD,
DWORD, HANDLE, HANDLE,
LPVOID data)
{
auto self = static_cast<Copier*>(data);
self->newStatus(totalTransferred.QuadPart, totalSize.QuadPart);
if (self->m_pause) {
QMutexLocker lock{&self->m_pauseMutex};
self->m_pauseWait.wait(&self->m_pauseMutex);
}
return PROGRESS_CONTINUE;
}
#endif
struct PathWidget : public QWidget {
QHBoxLayout layout{this};
QLineEdit edit;
QPushButton select{"..."};
QFileDialog dialog;
explicit PathWidget(const QString & caption) : dialog{this, caption} {
layout.setMargin(0);
layout.addWidget(&edit);
layout.addWidget(&select);
connect(&select, SIGNAL(clicked()), &dialog, SLOT(show()));
connect(&dialog, SIGNAL(fileSelected(QString)), &edit, SLOT(setText(QString)));
}
};
class Ui : public QWidget {
Q_OBJECT
QFormLayout m_layout{this};
QPlainTextEdit m_status;
PathWidget m_src{"Source File"}, m_dst{"Destination File"};
QPushButton m_copy{"Copy"};
QPushButton m_cancel{"Cancel"};
QStateMachine m_machine{this};
QState s_stopped{&m_machine};
QState s_copying{&m_machine};
Q_SIGNAL void stopCopy();
Q_SLOT void startCopy() {
auto copier = new Copier(m_src.edit.text(), m_dst.edit.text(), this);
connect(copier, SIGNAL(newStatus(QString)), &m_status, SLOT(appendPlainText(QString)));
connect(copier, SIGNAL(finished()), SIGNAL(copyFinished()));
connect(copier, SIGNAL(finished()), copier, SLOT(deleteLater()));
connect(this, SIGNAL(stopCopy()), copier, SLOT(stop()));
copier->copy();
}
Q_SIGNAL void copyFinished();
public:
Ui() {
m_layout.addRow("From:", &m_src);
m_layout.addRow("To:", &m_dst);
m_layout.addRow(&m_status);
m_layout.addRow(&m_copy);
m_layout.addRow(&m_cancel);
m_src.dialog.setFileMode(QFileDialog::ExistingFile);
m_dst.dialog.setAcceptMode(QFileDialog::AcceptSave);
m_status.setReadOnly(true);
m_status.setMaximumBlockCount(5);
m_machine.setInitialState(&s_stopped);
s_stopped.addTransition(&m_copy, SIGNAL(clicked()), &s_copying);
s_stopped.assignProperty(&m_copy, "enabled", true);
s_stopped.assignProperty(&m_cancel, "enabled", false);
s_copying.addTransition(&m_cancel, SIGNAL(clicked()), &s_stopped);
s_copying.addTransition(this, SIGNAL(copyFinished()), &s_stopped);
connect(&s_copying, SIGNAL(entered()), SLOT(startCopy()));
connect(&s_copying, SIGNAL(exited()), SIGNAL(stopCopy()));
s_copying.assignProperty(&m_copy, "enabled", false);
s_copying.assignProperty(&m_cancel, "enabled", true);
m_machine.start();
}
};
int main(int argc, char *argv[])
{
QApplication a{argc, argv};
Ui ui;
ui.show();
return a.exec();
}
#include "main.moc"