Do now allow multiple jobs with the same target file

As suggested here:
https://forum.shotcut.org/t/add-a-warning-and-an-option-to-create-a-new-file-name-when-two-identical-export-file-names-are-in-the-rendering-queue/47155

src/docks/encodedock.cpp

@@ -1262,6 +1262,13 @@ MeltJob *EncodeDock::createMeltJob(Mlt::Producer *service, const QString &target
     if (Util::warnIfNotWritable(target, this, caption))
         return nullptr;
 
+    if (JOBS.targetIsInProgress(target)) {
+        QMessageBox::warning(this, windowTitle(),
+                             QObject::tr("A job already exists for %1")
+                             .arg(target));
+        return nullptr;
+    }
+
     // if image sequence, change filename to include number
     QString mytarget = target;
     if (!ui->disableVideoCheckbox->isChecked()) {

src/docks/timelinedock.cpp

@@ -3864,6 +3864,7 @@ void TimelineDock::recordAudio()
 #endif
     args << "-flush_packets" << "1" << "-y" << filename;
     m_recordJob.reset(new FfmpegJob("vo", args, false, priority));
+    m_recordJob->setTarget(filename);
     connect(m_recordJob.get(), SIGNAL(started()), SLOT(onRecordStarted()));
     connect(m_recordJob.get(), SIGNAL(finished(AbstractJob *, bool)),
             SLOT(onRecordFinished(AbstractJob *, bool)));

src/jobqueue.cpp

@@ -227,7 +227,7 @@ void JobQueue::removeFinished()
     QMutexLocker locker(&m_mutex);
     auto row = 0;
     foreach (AbstractJob *job, m_jobs) {
-        if (job->ran() && job->state() != QProcess::Running) {
+        if (job->isFinished()) {
             removeRow(row);
             m_jobs.removeOne(job);
             delete job;
@@ -236,3 +236,15 @@ void JobQueue::removeFinished()
         }
     }
 }
+
+bool JobQueue::targetIsInProgress(const QString &target)
+{
+    if (!m_jobs.isEmpty() && !target.isEmpty()) {
+        foreach (AbstractJob *job, m_jobs) {
+            if (!job->isFinished() && job->target() == target) {
+                return true;
+            }
+        }
+    }
+    return false;
+}

src/jobqueue.h

@@ -53,6 +53,7 @@ class JobQueue : public QStandardItemModel
     {
         return m_jobs;
     }
+    bool targetIsInProgress(const QString &target);
 
 signals:
     void jobAdded();

src/jobs/abstractjob.h

@@ -41,6 +41,10 @@ class AbstractJob : public QProcess
     QStandardItem *standardItem();
     bool ran() const;
     bool stopped() const;
+    bool isFinished() const
+    {
+        return (ran() && state() != QProcess::Running);
+    }
     void appendToLog(const QString &);
     QString log() const;
     QString label() const
@@ -63,6 +67,14 @@ class AbstractJob : public QProcess
     }
     void setPostJobAction(PostJobAction *action);
     bool paused() const;
+    void setTarget(const QString & target)
+    {
+        m_target = target;
+    }
+    QString target()
+    {
+        return m_target;
+    }
 
 public slots:
     void start(const QString &program, const QStringList &arguments);
@@ -101,6 +113,7 @@ private slots:
     QAction *m_actionPause;
     QAction *m_actionResume;
     bool m_isPaused;
+    QString m_target;
 };
 
 #endif // ABSTRACTJOB_H

src/jobs/meltjob.cpp

@@ -38,6 +38,7 @@ MeltJob::MeltJob(const QString &name, const QString &xml, int frameRateNum, int
     , m_currentFrame(0)
     , m_useMultiConsumer(false)
 {
+    setTarget(name);
     if (!xml.isEmpty()) {
         QAction *action = new QAction(tr("View XML"), this);
         action->setToolTip(tr("View the MLT XML for this job"));

src/jobs/qimagejob.cpp

@@ -29,6 +29,7 @@ QImageJob::QImageJob(const QString &destFilePath, const QString &srcFilePath, co
     , m_destFilePath(destFilePath)
     , m_height(height)
 {
+    setTarget(destFilePath);
     setLabel(tr("Make proxy for %1").arg(Util::baseName(srcFilePath)));
 }
 

src/jobs/whisperjob.cpp

@@ -38,6 +38,7 @@ WhisperJob::WhisperJob(const QString &name, const QString &iWavFile, const QStri
     , m_maxLength(maxLength)
     , m_previousPercent(0)
 {
+    setTarget(oSrtFile);
 }
 
 WhisperJob::~WhisperJob()

src/proxymanager.cpp

@@ -92,6 +92,11 @@ void ProxyManager::generateVideoProxy(Mlt::Producer &producer, bool fullRange, S
     auto hwCodecs = Settings.encodeHardware();
     QString hwFilters;
 
+    if (JOBS.targetIsInProgress(fileName)) {
+        LOG_ERROR() << "A job is already in progress for" << fileName;
+        return;
+    }
+
     // Touch file to make it in progress
     QFile file(fileName);
     file.open(QIODevice::WriteOnly);
@@ -248,6 +253,7 @@ void ProxyManager::generateVideoProxy(Mlt::Producer &producer, bool fullRange, S
 
     FfmpegJob *job = new FfmpegJob(fileName, args, true);
     job->setLabel(QObject::tr("Make proxy for %1").arg(Util::baseName(resource)));
+    job->setTarget(fileName);
     if (replace) {
         job->setPostJobAction(new ProxyReplacePostJobAction(resource, fileName, hash));
     } else {

src/transcoder.cpp

@@ -94,6 +94,10 @@ void Transcoder::convert(TranscodeDialog &dialog)
                                      .arg(fi.fileName()));
                 return;
             }
+            if (JOBS.targetIsInProgress(filename)) {
+                MAIN.showStatusMessage(tr("A job already exists for %1").arg(filename));
+                return;
+            }
             if (Util::warnIfNotWritable(filename, MAIN.centralWidget(), dialog.windowTitle()))
                 return;
 
@@ -123,6 +127,12 @@ void Transcoder::convert(TranscodeDialog &dialog)
             QFileInfo fi(resource);
             filename = path + nameFormat.arg(fi.completeBaseName(), suffix);
             filename = Util::getNextFile(filename);
+            if (JOBS.targetIsInProgress(filename)) {
+                if (JOBS.targetIsInProgress(filename)) {
+                    MAIN.showStatusMessage(tr("A job already exists for %1").arg(filename));
+                    return;
+                }
+            }
             convertProducer(&producer, dialog, filename);
         }
     }
@@ -274,6 +284,7 @@ void Transcoder::convertProducer(Mlt::Producer *producer, TranscodeDialog &dialo
 
     FfmpegJob *job = new FfmpegJob(filename, args, false);
     job->setLabel(tr("Convert %1").arg(Util::baseName(filename)));
+    job->setTarget(filename);
     if (dialog.isSubClip()) {
         if (producer->get(kMultitrackItemProperty)) {
             QString s = QString::fromLatin1(producer->get(kMultitrackItemProperty));

src/widgets/avformatproducerwidget.cpp

@@ -956,6 +956,12 @@ void AvformatProducerWidget::on_reverseButton_clicked()
                                      .arg(fi.fileName()));
                 return;
             }
+            if (JOBS.targetIsInProgress(filename)) {
+                QMessageBox::warning(this, dialog.windowTitle(),
+                                     QObject::tr("A job already exists for %1")
+                                     .arg(filename));
+                return;
+            }
             if (Util::warnIfNotWritable(filename, this, dialog.windowTitle()))
                 return;
 
@@ -989,6 +995,7 @@ void AvformatProducerWidget::on_reverseButton_clicked()
             MeltJob *meltJob = new MeltJob(filename, meltArgs,
                                            m_producer->get_int("meta.media.frame_rate_num"), m_producer->get_int("meta.media.frame_rate_den"));
             meltJob->setLabel(tr("Reverse %1").arg(Util::baseName(resource)));
+            meltJob->setTarget(filename);
 
             if (m_producer->get(kMultitrackItemProperty)) {
                 QString s = QString::fromLatin1(m_producer->get(kMultitrackItemProperty));
@@ -1034,6 +1041,12 @@ void AvformatProducerWidget::on_actionExtractSubclip_triggered()
                                  .arg(fi.fileName()));
             return;
         }
+        if (JOBS.targetIsInProgress(filename)) {
+            QMessageBox::warning(this, caption,
+                                 QObject::tr("A job already exists for %1")
+                                 .arg(filename));
+            return;
+        }
         if (Util::warnIfNotWritable(filename, this, caption))
             return;
         Settings.setSavePath(QFileInfo(filename).path());
@@ -1066,6 +1079,7 @@ void AvformatProducerWidget::on_actionExtractSubclip_triggered()
         // Run the ffmpeg job.
         FfmpegJob *ffmpegJob = new FfmpegJob(filename, ffmpegArgs, false);
         ffmpegJob->setLabel(tr("Extract sub-clip %1").arg(Util::baseName(resource)));
+        ffmpegJob->setTarget(filename);
         JOBS.add(ffmpegJob);
     }
 }