From 7718b0748e2b8378942e892da34c8fa3af22bc70 Mon Sep 17 00:00:00 2001
From: Roman Telezhynskyi <kroluku@gmail.com>
Date: Tue, 15 Sep 2015 21:21:51 +0300
Subject: [PATCH] Show a message box with an error. Release a lock file after
 error.

--HG--
branch : develop
---
 src/app/tape/mapplication.cpp | 90 +++++++++++++++++++++++++++++++++++
 src/app/tape/tmainwindow.cpp  |  2 +
 2 files changed, 92 insertions(+)

diff --git a/src/app/tape/mapplication.cpp b/src/app/tape/mapplication.cpp
index 0533b44c9..bb9a11292 100644
--- a/src/app/tape/mapplication.cpp
+++ b/src/app/tape/mapplication.cpp
@@ -38,6 +38,8 @@
 #include <QTranslator>
 #include <QPointer>
 #include <QLocalServer>
+#include <QMessageBox>
+#include <iostream>
 
 #if QT_VERSION < QT_VERSION_CHECK(5, 2, 0)
 #   include "../../libs/vmisc/backport/qcommandlineparser.h"
@@ -45,6 +47,92 @@
 #   include <QCommandLineParser>
 #endif
 
+//---------------------------------------------------------------------------------------------------------------------
+inline void noisyFailureMsgHandler(QtMsgType type, const QMessageLogContext &context, const QString &msg)
+{
+    Q_UNUSED(context)
+
+    // Why on earth didn't Qt want to make failed signal/slot connections qWarning?
+    if ((type == QtDebugMsg) && msg.contains("::connect"))
+    {
+        type = QtWarningMsg;
+    }
+
+    // this is another one that doesn't make sense as just a debug message.  pretty serious
+    // sign of a problem
+    // http://www.developer.nokia.com/Community/Wiki/QPainter::begin:Paint_device_returned_engine_%3D%3D_0_(Known_Issue)
+    if ((type == QtDebugMsg) && msg.contains("QPainter::begin") && msg.contains("Paint device returned engine"))
+    {
+        type = QtWarningMsg;
+    }
+
+    // This qWarning about "Cowardly refusing to send clipboard message to hung application..."
+    // is something that can easily happen if you are debugging and the application is paused.
+    // As it is so common, not worth popping up a dialog.
+    if ((type == QtWarningMsg) && QString(msg).contains("QClipboard::event")
+            && QString(msg).contains("Cowardly refusing"))
+    {
+        type = QtDebugMsg;
+    }
+
+    // only the GUI thread should display message boxes.  If you are
+    // writing a multithreaded application and the error happens on
+    // a non-GUI thread, you'll have to queue the message to the GUI
+    QCoreApplication *instance = QCoreApplication::instance();
+    const bool isGuiThread = instance && (QThread::currentThread() == instance->thread());
+
+    if (isGuiThread)
+    {
+        //fixme: trying to make sure there are no save/load dialogs are opened, because error message during them will
+        //lead to crash
+        const bool topWinAllowsPop = (qApp->activeModalWidget() == nullptr) ||
+                !qApp->activeModalWidget()->inherits("QFileDialog");
+        QMessageBox messageBox;
+        switch (type)
+        {
+            case QtDebugMsg:
+                std::cerr << msg.toUtf8().constData();
+                std::cerr.flush();
+                return;
+            case QtWarningMsg:
+                messageBox.setIcon(QMessageBox::Warning);
+                break;
+            case QtCriticalMsg:
+                messageBox.setIcon(QMessageBox::Critical);
+                break;
+            case QtFatalMsg:
+                messageBox.setIcon(QMessageBox::Critical);
+                break;
+            default:
+                break;
+        }
+
+        if (type == QtWarningMsg || type == QtCriticalMsg || type == QtFatalMsg)
+        {
+            if (topWinAllowsPop)
+            {
+                messageBox.setInformativeText(msg);
+                messageBox.setStandardButtons(QMessageBox::Ok);
+                messageBox.setWindowModality(Qt::ApplicationModal);
+                messageBox.setModal(true);
+                messageBox.exec();
+            }
+        }
+
+        if (QtFatalMsg == type)
+        {
+            abort();
+        }
+    }
+    else
+    {
+        if (type != QtDebugMsg)
+        {
+            abort(); // be NOISY unless overridden!
+        }
+    }
+}
+
 //---------------------------------------------------------------------------------------------------------------------
 MApplication::MApplication(int &argc, char **argv)
     :VAbstractApplication(argc, argv),
@@ -138,6 +226,8 @@ QList<TMainWindow *> MApplication::MainWindows()
 //---------------------------------------------------------------------------------------------------------------------
 void MApplication::InitOptions()
 {
+    qInstallMessageHandler(noisyFailureMsgHandler);
+
     OpenSettings();
 
     qDebug()<<"Version:"<<APP_VERSION_STR;
diff --git a/src/app/tape/tmainwindow.cpp b/src/app/tape/tmainwindow.cpp
index 4e39e180b..2be9b9cc4 100644
--- a/src/app/tape/tmainwindow.cpp
+++ b/src/app/tape/tmainwindow.cpp
@@ -183,6 +183,7 @@ void TMainWindow::LoadFile(const QString &path)
         if (lock->GetLockError() == QLockFile::LockFailedError)
         {
             qCCritical(tMainWindow, "%s", tr("This file already opened in another window.").toUtf8().constData());
+            lock.reset();
             return;
         }
 
@@ -248,6 +249,7 @@ void TMainWindow::LoadFile(const QString &path)
             m = nullptr;
             delete data;
             data = nullptr;
+            lock.reset();
             return;
         }
     }