Merge pull request #17609 from wwmayer/issue_17576

Core: Don't freeze application if lock file already exists

src/App/Application.cpp

@@ -47,6 +47,7 @@
 #include <sys/sysctl.h>
 #endif
 
+#include <QCoreApplication>
 #include <QDir>
 #include <QFileInfo>
 #include <QProcessEnvironment>
@@ -1114,6 +1115,11 @@ Application::TransactionSignaller::~TransactionSignaller() {
     }
 }
 
+int64_t Application::applicationPid()
+{
+    return QCoreApplication::applicationPid();
+}
+
 std::string Application::getHomePath()
 {
     return mConfig["AppHomePath"];

src/App/Application.h

@@ -399,6 +399,7 @@ public:
     static std::map<std::string, std::string> &Config(){return mConfig;}
     static int GetARGC(){return _argc;}
     static char** GetARGV(){return _argv;}
+    static int64_t applicationPid();
     //@}
 
     /** @name Application directories */

src/App/Document.cpp

@@ -931,18 +931,21 @@ Document::~Document()
 std::string Document::getTransientDirectoryName(const std::string& uuid, const std::string& filename) const
 {
     // Create a directory name of the form: {ExeName}_Doc_{UUID}_{HASH}_{PID}
-    std::stringstream s;
+    std::stringstream out;
     QCryptographicHash hash(QCryptographicHash::Sha1);
 #if QT_VERSION < QT_VERSION_CHECK(6,3,0)
     hash.addData(filename.c_str(), filename.size());
 #else
     hash.addData(QByteArrayView(filename.c_str(), filename.size()));
 #endif
-    s << App::Application::getUserCachePath() << App::Application::getExecutableName()
-      << "_Doc_" << uuid
-      << "_" << hash.result().toHex().left(6).constData()
-      << "_" << QCoreApplication::applicationPid();
-    return s.str();
+    out << App::Application::getUserCachePath() << App::Application::getExecutableName()
+        << "_Doc_"
+        << uuid
+        << "_"
+        << hash.result().toHex().left(6).constData()
+        << "_"
+        << App::Application::applicationPid();
+    return out.str();
 }
 
 //--------------------------------------------------------------------------

src/Gui/Application.cpp

@@ -2172,46 +2172,51 @@ void setAppNameAndIcon()
 
 void tryRunEventLoop(GUISingleApplication& mainApp)
 {
-    std::stringstream s;
-    s << App::Application::getUserCachePath() << App::Application::getExecutableName() << "_"
-      << QCoreApplication::applicationPid() << ".lock";
+    std::stringstream out;
+    out << App::Application::getUserCachePath()
+        << App::Application::getExecutableName()
+        << "_"
+        << App::Application::applicationPid()
+        << ".lock";
+
     // open a lock file with the PID
-    Base::FileInfo fi(s.str());
+    Base::FileInfo fi(out.str());
     Base::ofstream lock(fi);
 
     // In case the file_lock cannot be created start FreeCAD without IPC support.
 #if !defined(FC_OS_WIN32) || (BOOST_VERSION < 107600)
-    std::string filename = s.str();
+    std::string filename = out.str();
 #else
     std::wstring filename = fi.toStdWString();
 #endif
-    std::unique_ptr<boost::interprocess::file_lock> flock;
     try {
-        flock = std::make_unique<boost::interprocess::file_lock>(filename.c_str());
-        flock->lock();
+        boost::interprocess::file_lock flock(filename.c_str());
+        if (flock.try_lock()) {
+            Base::Console().Log("Init: Executing event loop...\n");
+            QApplication::exec();
+
+            // Qt can't handle exceptions thrown from event handlers, so we need
+            // to manually rethrow SystemExitExceptions.
+            if (mainApp.caughtException) {
+                throw Base::SystemExitException(*mainApp.caughtException.get());
+            }
+
+            // close the lock file, in case of a crash we can see the existing lock file
+            // on the next restart and try to repair the documents, if needed.
+            flock.unlock();
+            lock.close();
+            fi.deleteFile();
+        }
+        else {
+            Base::Console().Warning("Failed to create a file lock for the IPC.\n"
+                                    "The application will be terminated\n");
+        }
     }
     catch (const boost::interprocess::interprocess_exception& e) {
         QString msg = QString::fromLocal8Bit(e.what());
         Base::Console().Warning("Failed to create a file lock for the IPC: %s\n",
                                 msg.toUtf8().constData());
     }
-
-    Base::Console().Log("Init: Executing event loop...\n");
-    QApplication::exec();
-
-    // Qt can't handle exceptions thrown from event handlers, so we need
-    // to manually rethrow SystemExitExceptions.
-    if (mainApp.caughtException) {
-        throw Base::SystemExitException(*mainApp.caughtException.get());
-    }
-
-    // close the lock file, in case of a crash we can see the existing lock file
-    // on the next restart and try to repair the documents, if needed.
-    if (flock) {
-        flock->unlock();
-    }
-    lock.close();
-    fi.deleteFile();
 }
 
 void runEventLoop(GUISingleApplication& mainApp)

src/Gui/DocumentRecovery.cpp

@@ -651,12 +651,12 @@ void DocumentRecoveryHandler::checkForPreviousCrashes(const std::function<void(Q
 
     QString exeName = QString::fromStdString(App::Application::getExecutableName());
     QList<QFileInfo> locks = tmp.entryInfoList();
-    for (QList<QFileInfo>::iterator it = locks.begin(); it != locks.end(); ++it) {
-        QString bn = it->baseName();
+    for (const QFileInfo&  it : locks) {
+        QString bn = it.baseName();
         // ignore the lock file for this instance
-        QString pid = QString::number(QCoreApplication::applicationPid());
+        QString pid = QString::number(App::Application::applicationPid());
         if (bn.startsWith(exeName) && bn.indexOf(pid) < 0) {
-            QString fn = it->absoluteFilePath();
+            QString fn = it.absoluteFilePath();
 
 #if !defined(FC_OS_WIN32) || (BOOST_VERSION < 107600)
             boost::interprocess::file_lock flock(fn.toUtf8());
@@ -665,7 +665,7 @@ void DocumentRecoveryHandler::checkForPreviousCrashes(const std::function<void(Q
 #endif
             if (flock.try_lock()) {
                 // OK, this file is a leftover from a previous crash
-                QString crashed_pid = bn.mid(exeName.length()+1);
+                QString crashed_pid = bn.mid(exeName.length() + 1);
                 // search for transient directories with this PID
                 QString filter;
                 QTextStream str(&filter);
@@ -674,7 +674,10 @@ void DocumentRecoveryHandler::checkForPreviousCrashes(const std::function<void(Q
                 tmp.setFilter(QDir::Dirs);
                 QList<QFileInfo> dirs = tmp.entryInfoList();
 
-                callableFunc(tmp, dirs, it->fileName());
+                callableFunc(tmp, dirs, it.fileName());
+            }
+            else {
+                Base::Console().Log("Failed to lock file %s\n", fn.toUtf8().constData());
             }
         }
     }