Updater|Win32: Ask to stop Snowberry if it is running

As Windows cannot update files that are in use, we must ask the
user to quit Snowberry before the installer is started.

doomsday/engine/engine.pro

@@ -365,6 +365,7 @@ DENG_HEADERS += \
     portable/include/zipfile.h \
     portable/include/zonedebug.h \
     portable/src/updater/downloaddialog.h \
+    portable/src/updater/processcheckdialog.h \
     portable/src/updater/updateavailabledialog.h \
     portable/src/updater/updaterdialog.h \
     portable/src/updater/updatersettings.h \
@@ -645,6 +646,7 @@ SOURCES += \
     portable/src/ui_panel.c \
     portable/src/updater.cpp \
     portable/src/updater/downloaddialog.cpp \
+    portable/src/updater/processcheckdialog.cpp \
     portable/src/updater/updateavailabledialog.cpp \
     portable/src/updater/updaterdialog.cpp \
     portable/src/updater/updatersettings.cpp \

doomsday/engine/portable/src/updater.cpp

@@ -53,6 +53,7 @@
 #include "json.h"
 #include "updater.h"
 #include "updater/downloaddialog.h"
+#include "updater/processcheckdialog.h"
 #include "updater/updateavailabledialog.h"
 #include "updater/updatersettings.h"
 #include "updater/updatersettingsdialog.h"
@@ -403,6 +404,10 @@ struct Updater::Instance
         atexit(runInstallerCommand);
 
 #elif defined(WIN32)
+        Updater_AskToStopProcess("snowberry.exe", "Please quit the Doomsday Engine Frontend "
+                                 "before starting the update. Windows cannot update "
+                                 "files that are currently in use.");
+
         // The distribution package is an installer executable, we can just run it.
         installerCommand = new de::CommandLine;
         installerCommand->append(distribPackagePath);

doomsday/engine/portable/src/updater/processcheckdialog.cpp

@@ -0,0 +1,61 @@
+/**
+ * @file processcheckdialog.cpp
+ * Dialog for checking running processes on Windows. @ingroup updater
+ *
+ * @authors Copyright © 2012 Jaakko Keränen <jaakko.keranen@iki.fi>
+ *
+ * @par License
+ * GPL: http://www.gnu.org/licenses/gpl.html
+ *
+ * <small>This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version. This program is distributed in the hope that it
+ * will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
+ * Public License for more details. You should have received a copy of the GNU
+ * General Public License along with this program; if not, write to the Free
+ * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
+ * 02110-1301 USA</small>
+ */
+
+#include "processcheckdialog.h"
+#include <QMessageBox>
+#include <QProcess>
+#include <QDebug>
+
+#ifdef WIN32
+
+static bool isProcessRunning(const char* name)
+{
+    QProcess wmic;
+    wmic.start("wmic.exe", QStringList() << "PROCESS" << "get" << "Caption");
+    if(!wmic.waitForStarted()) return false;
+    if(!wmic.waitForFinished()) return false;
+
+    QByteArray result = wmic.readAll();
+    foreach(QString p, QString(result).split("\n", QString::SkipEmptyParts))
+    {
+        if(!p.trimmed().compare(QLatin1String(name), Qt::CaseInsensitive))
+            return true;
+    }
+    return false;
+}
+
+boolean Updater_AskToStopProcess(const char* processName, const char* message)
+{
+    while(isProcessRunning(processName))
+    {
+        // Show a notification dialog.
+        QMessageBox msg(QMessageBox::Warning, "Files In Use", message,
+                        QMessageBox::Retry | QMessageBox::Ignore);
+        msg.setInformativeText(QString("(There is a running process called <b>%1</b>.)").arg(processName));
+        if(msg.exec() == QMessageBox::Ignore)
+        {
+            return !isProcessRunning(processName);
+        }
+    }
+    return true;
+}
+
+#endif // WIN32

doomsday/engine/portable/src/updater/processcheckdialog.h

@@ -0,0 +1,56 @@
+/**
+ * @file processcheckdialog.h
+ * Dialog for checking running processes on Windows. @ingroup updater
+ *
+ * Windows cannot overwrite files that are in use. Thus the updater needs
+ * to ensure that all Snowberry is shut down before starting an update.
+ *
+ * @authors Copyright © 2012 Jaakko Keränen <jaakko.keranen@iki.fi>
+ *
+ * @par License
+ * GPL: http://www.gnu.org/licenses/gpl.html
+ *
+ * <small>This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version. This program is distributed in the hope that it
+ * will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
+ * Public License for more details. You should have received a copy of the GNU
+ * General Public License along with this program; if not, write to the Free
+ * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
+ * 02110-1301 USA</small>
+ */
+
+#ifndef LIBDENG_PROCESSCHECKDIALOG_H
+#define LIBDENG_PROCESSCHECKDIALOG_H
+
+#include <de/types.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+// This is only for Windows.
+#ifdef WIN32
+
+/**
+ * Asks the user to stop a process if it is found to be running.
+ *
+ * @param processName  Name of the process to check for (e.g., "snowberry.exe").
+ * @param message      Message to display to the user if the process is
+ *                     running. Should describe why the process needs to be
+ *                     stopped.
+ *
+ * @return  @c true, if the process has been stopped. Otherwise @c false,
+ * the process is still running.
+ */
+boolean Updater_AskToStopProcess(const char* processName, const char* message);
+
+#endif // WIN32
+
+#ifdef __cplusplus
+} // extern "C"
+#endif
+
+#endif // LIBDENG_PROCESSCHECKDIALOG_H