WIP: working on support for autosave with multiple instances

YUViewApp/src/yuviewapp.cpp

@@ -34,6 +34,7 @@
 
 #include "common/typedef.h"
 #include "ui/YUViewApplication.h"
+#include "common/YUViewInstanceInfo.h"
 
 int main(int argc, char *argv[])
 {
@@ -45,7 +46,11 @@ int main(int argc, char *argv[])
   QCoreApplication::setAttribute(Qt::AA_SynthesizeTouchForUnhandledMouseEvents,false);
 
   qRegisterMetaType<recacheIndicator>("recacheIndicator");
-
+  qRegisterMetaType<YUViewInstanceInfo>("YUViewInstanceInfo");
+  qRegisterMetaType<YUViewInstanceInfoList>("YUViewInstanceInfoList");
+  qRegisterMetaTypeStreamOperators<YUViewInstanceInfo>("YUViewInstanceInfo");
+  qRegisterMetaTypeStreamOperators<YUViewInstanceInfoList>("YUViewInstanceInfoList");
+
   YUViewApplication app(argc, argv);
 
   return app.returnCode;

YUViewLib/src/common/EnumMapper.h

@@ -36,6 +36,7 @@
 #include <optional>
 #include <string>
 #include <vector>
+#include <stdexcept>
 
 /* This class implement mapping of "enum class" values to and from names (string).
  */

YUViewLib/src/common/YUViewInstanceInfo.cpp

@@ -0,0 +1,294 @@
+#include "YUViewInstanceInfo.h"
+#include <QCoreApplication>
+#include <QProcess>
+#include <QSettings>
+
+
+const QString YUViewInstanceInfo::instanceInfoKey = QString("YUViewInstances");
+
+
+QDataStream& operator<<(QDataStream &ds, const YUViewInstanceInfo &inObj)
+{
+  ds << inObj.uuid;
+  // conversion to string should not be necessary.
+  // but without I get ambiguous overload for operator
+  ds << QString::number(inObj.pid);
+  ds << inObj.compressedPlaylist;
+  return ds;
+}
+
+QDataStream& operator>>(QDataStream &ds, YUViewInstanceInfo &outObj)
+{
+  ds >> outObj.uuid;
+  QString tmp;
+  ds >> tmp;
+  outObj.pid = tmp.toLongLong();
+  ds >> outObj.compressedPlaylist;
+  return ds;
+}
+
+QDataStream& operator<<(QDataStream &ds, const YUViewInstanceInfoList &inObj)
+{
+  const qint64 list_length = inObj.length();
+  // conversion to string should not be necessary.
+  // but without I get ambiguous overload for operator
+  ds <<  QString::number(list_length);
+  for( auto instance : inObj )
+  {
+    ds << instance;
+  }
+  return ds;
+}
+
+QDataStream& operator>>(QDataStream &ds, YUViewInstanceInfoList &outObj)
+{
+  outObj.clear();
+  QString tmp;
+  ds >> tmp;
+  const qint64 list_length = tmp.toLongLong();
+  for(unsigned i = 0; i<list_length; i++)
+  {
+    YUViewInstanceInfo tmp;
+    ds >> tmp;
+    outObj.push_back(tmp);
+  }
+  return ds;
+}
+
+void YUViewInstanceInfo::initializeAsNewInstance()
+{
+  QSettings settings;
+  uuid = QUuid::createUuid();
+  pid = QCoreApplication::applicationPid();
+  // append instance to recorded ones
+  YUViewInstanceInfoList listOfQSettingInstances = YUViewInstanceInfo::getYUViewInstancesInQSettings();
+  listOfQSettingInstances.append(*this);
+  settings.setValue(instanceInfoKey, QVariant::fromValue(listOfQSettingInstances));
+}
+
+void YUViewInstanceInfo::autoSavePlaylist(const QByteArray &newCompressedPlaylist)
+{
+  QSettings settings;
+  // set new playlist
+  this->compressedPlaylist = newCompressedPlaylist;
+
+  // change the one stored
+  YUViewInstanceInfoList listOfQSettingInstances = YUViewInstanceInfo::getYUViewInstancesInQSettings();
+  QMutableListIterator<YUViewInstanceInfo> it(listOfQSettingInstances);
+  while (it.hasNext())
+  {
+    YUViewInstanceInfo otherInstance = it.next();
+    if(this->uuid == otherInstance.uuid &&
+       this->pid == otherInstance.pid )
+    {
+      // already had a instance, replace its playlist
+      it.setValue(*this);
+      settings.setValue(instanceInfoKey, QVariant::fromValue(listOfQSettingInstances));      
+      return;
+    }
+  }
+
+  // no instance yet, save new one
+  // should never be reached, as we create the instance in initializeAsNewInstance,
+  // thus there always should be one
+  listOfQSettingInstances.append(*this);
+  settings.setValue(instanceInfoKey, QVariant::fromValue(listOfQSettingInstances));
+  return;
+}
+
+void YUViewInstanceInfo::dropAutosavedPlaylist()
+{
+  // replace saved on with emtpy playlist
+  this->autoSavePlaylist(QByteArray());
+}
+
+void YUViewInstanceInfo::removeInstanceFromQSettings()
+{
+  QSettings settings;
+
+  // find and remove current instance from stored ones
+  YUViewInstanceInfoList listOfQSettingInstances = YUViewInstanceInfo::getYUViewInstancesInQSettings();
+  QMutableListIterator<YUViewInstanceInfo> it(listOfQSettingInstances);
+  while (it.hasNext())
+  {
+    YUViewInstanceInfo otherInstance = it.next();
+    if(this->uuid == otherInstance.uuid &&
+       this->pid == otherInstance.pid )
+    {
+      // found it, now remove it
+      it.remove();
+      settings.setValue(instanceInfoKey, QVariant::fromValue(listOfQSettingInstances));
+      return;
+    }
+  }
+}
+
+YUViewInstanceInfo YUViewInstanceInfo::getAutosavedPlaylist()
+{
+  QSettings settings;
+  QList<qint64> listOfPids = YUViewInstanceInfo::getRunningYUViewInstances();
+  YUViewInstanceInfoList listOfQSettingInstances = YUViewInstanceInfo::getYUViewInstancesInQSettings();
+
+  YUViewInstanceInfo candidateForRestore;
+  QMutableListIterator<YUViewInstanceInfo> it(listOfQSettingInstances);
+  while (it.hasNext())
+  {
+    YUViewInstanceInfo instanceInSettings = it.next();
+    bool still_running = false;
+    // get known instances, if instance no longer runs, remove it from QSettings
+    for( auto pid_running : listOfPids )
+    {
+      if( pid_running == instanceInSettings.pid )  still_running = true;
+    }
+    if(!still_running)
+    {
+      // found an instance which is no longer running: candidate for restore
+      candidateForRestore = instanceInSettings;
+      it.remove();
+      settings.setValue(instanceInfoKey, QVariant::fromValue(listOfQSettingInstances));
+      break; // keep playlist from potential other crashed instances for other new instances
+    }
+  }
+
+  return candidateForRestore;
+}
+
+void YUViewInstanceInfo::cleanupRecordedInstances()
+{
+  QSettings settings;
+  QList<qint64> listOfPids = YUViewInstanceInfo::getRunningYUViewInstances();
+  YUViewInstanceInfoList listOfQSettingInstances = YUViewInstanceInfo::getYUViewInstancesInQSettings();
+
+  QMutableListIterator<YUViewInstanceInfo> it(listOfQSettingInstances);
+  while (it.hasNext())
+  {
+    YUViewInstanceInfo instanceInSettings = it.next();
+    bool still_running = false;
+    // get known instances, if instance no longer runs, remove it from QSettings
+    for( auto pid_running : listOfPids )
+    {
+      if( pid_running == instanceInSettings.pid )  still_running = true;
+    }
+    if(!still_running)
+    {
+      // can remove this one
+      it.remove();
+    }
+  }
+
+  settings.setValue(instanceInfoKey, QVariant::fromValue(listOfQSettingInstances));
+}
+
+bool YUViewInstanceInfo::isValid()
+{
+  return !uuid.isNull();
+}
+
+QList<qint64> YUViewInstanceInfo::getRunningYUViewInstances()
+{
+
+  QList<qint64> listOfPids;
+
+  // code for getting process ids adopted from https://www.qtcentre.org/threads/44489-Get-Process-ID-for-a-running-application
+  // also mentions checking /proc. However there is no proc on macos, while pgrep should be available.
+
+#if defined(Q_OS_WIN)
+    // Get the list of process identifiers.
+    DWORD aProcesses[1024], cbNeeded, cProcesses;
+    unsigned int i;
+
+    if (!EnumProcesses(aProcesses, sizeof(aProcesses), &cbNeeded))
+    {
+        return 0;
+    }
+
+    // Calculate how many process identifiers were returned.
+    cProcesses = cbNeeded / sizeof(DWORD);
+
+    // Search for a matching name for each process
+    for (i = 0; i < cProcesses; i++)
+    {
+        if (aProcesses[i] != 0)
+        {
+            char szProcessName[MAX_PATH] = {0};
+
+            DWORD processID = aProcesses[i];
+
+            // Get a handle to the process.
+            HANDLE hProcess = OpenProcess( PROCESS_QUERY_INFORMATION |
+                PROCESS_VM_READ,
+                FALSE, processID);
+
+            // Get the process name
+            if (NULL != hProcess)
+            {
+                HMODULE hMod;
+                DWORD cbNeeded;
+
+                if (EnumProcessModules(hProcess, &hMod, sizeof(hMod), &cbNeeded))
+                {
+                    GetModuleBaseNameA(hProcess, hMod, szProcessName, sizeof(szProcessName)/sizeof(char));
+                }
+
+                // Release the handle to the process.
+                CloseHandle(hProcess);
+
+                if (*szProcessName != 0 && strcmp(processName, szProcessName) == 0)
+                {
+                    listOfPids.append(QString::number(processID));
+                }
+            }
+        }
+    }
+
+    return listOfPids.count();
+
+#else
+
+  // Run pgrep, which looks through the currently running processses and lists the process IDs
+  // which match the selection criteria to stdout.
+  QProcess process;
+  process.start("pgrep",  QStringList() << "YUView");
+  process.waitForReadyRead();
+
+  QByteArray bytes = process.readAllStandardOutput();
+
+  process.terminate();
+  process.waitForFinished();
+  process.kill();
+
+  // Output is something like "2472\n2323" for multiple instances
+  if (bytes.isEmpty())
+      return QList<qint64>();
+
+  // Remove trailing CR
+  if (bytes.endsWith("\n"))
+      bytes.resize(bytes.size() - 1);
+
+  QStringList strListOfPids = QString(bytes).split("\n");
+  for( auto strPid : strListOfPids )
+  {
+    listOfPids.append(strPid.toLongLong());
+  }
+#endif
+
+  return  listOfPids;
+}
+
+YUViewInstanceInfoList YUViewInstanceInfo::getYUViewInstancesInQSettings()
+{
+  QSettings settings;
+  YUViewInstanceInfoList instancesInQSettings;
+  if (settings.contains(instanceInfoKey))
+  {
+    instancesInQSettings = settings.value(instanceInfoKey).value<YUViewInstanceInfoList>();
+  }
+  return instancesInQSettings;
+}
+
+QByteArray YUViewInstanceInfo::getCompressedPlaylist() const
+{
+  return compressedPlaylist;
+}
+
+

YUViewLib/src/common/YUViewInstanceInfo.h

@@ -0,0 +1,52 @@
+#ifndef YUVIEWINSTANCEINFO_H
+#define YUVIEWINSTANCEINFO_H
+
+#include <QMetaType>
+#include <QStringList>
+#include <QUuid>
+#include <QList>
+
+class YUViewInstanceInfo;
+typedef QList<YUViewInstanceInfo> YUViewInstanceInfoList;
+
+class YUViewInstanceInfo
+{
+public:
+    YUViewInstanceInfo() = default;
+    ~YUViewInstanceInfo() = default;
+    YUViewInstanceInfo(const YUViewInstanceInfo &) = default;
+    YUViewInstanceInfo &operator=(const YUViewInstanceInfo &) = default;
+
+    void initializeAsNewInstance();
+    void autoSavePlaylist(const QByteArray &newCompressedPlaylist);
+    void dropAutosavedPlaylist();
+    void removeInstanceFromQSettings();
+    YUViewInstanceInfo getAutosavedPlaylist();
+    void cleanupRecordedInstances();
+    bool isValid();
+
+    QByteArray getCompressedPlaylist() const;
+
+    friend QDataStream& (operator<<) (QDataStream &ds, const YUViewInstanceInfo &inObj);
+    friend QDataStream& (operator>>) (QDataStream &ds, YUViewInstanceInfo &outObj);
+private:
+    static QList<qint64> getRunningYUViewInstances();
+    static YUViewInstanceInfoList getYUViewInstancesInQSettings();
+
+    qint64 pid;
+    QUuid uuid;
+    QByteArray compressedPlaylist;
+
+    static const QString instanceInfoKey; // key used for QSettings
+};
+
+QDataStream& operator<<(QDataStream &ds, const YUViewInstanceInfo &inObj);
+QDataStream& operator>>(QDataStream &ds, YUViewInstanceInfo &outObj);
+QDataStream& operator<<(QDataStream &ds, const YUViewInstanceInfoList &inObj);
+QDataStream& operator>>(QDataStream &ds, YUViewInstanceInfoList &outObj);
+
+Q_DECLARE_METATYPE(YUViewInstanceInfo);
+Q_DECLARE_METATYPE(YUViewInstanceInfoList);
+
+
+#endif // YUVIEWINSTANCEINFO_H

YUViewLib/src/playlistitem/playlistItemCompressedVideo.cpp

@@ -395,7 +395,8 @@ playlistItemCompressedVideo::newPlaylistItemCompressedVideo(const YUViewDomEleme
                                                             const QString &playlistFilePath)
 {
   // Parse the DOM element. It should have all values of a playlistItemRawCodedVideo
-  auto absolutePath  = root.findChildValue("absolutePath");
+  QUrl absoluteUrl = root.findChildValue("absolutePath");
+  auto absolutePath = absoluteUrl.toLocalFile();
   auto relativePath  = root.findChildValue("relativePath");
   int  displaySignal = root.findChildValue("displayComponent").toInt();
 

YUViewLib/src/playlistitem/playlistItemImageFile.cpp

@@ -109,7 +109,8 @@ playlistItemImageFile::newplaylistItemImageFile(const YUViewDomElement &root,
                                                 const QString &         playlistFilePath)
 {
   // Parse the DOM element. It should have all values of a playlistItemImageFile
-  QString absolutePath = root.findChildValue("absolutePath");
+  QUrl absoluteUrl = root.findChildValue("absolutePath");
+  auto absolutePath = absoluteUrl.toLocalFile();
   QString relativePath = root.findChildValue("relativePath");
 
   // check if file with absolute path exists, otherwise check relative path