From e7bf0edfd49de9a4d8285fbe8d878f8fda910e6d Mon Sep 17 00:00:00 2001
From: Andreas Hartmetz <ahartmetz@gmail.com>
Date: Tue, 19 Jan 2016 14:30:18 +0100
Subject: [PATCH] Add option to disable "session management by closing
windows".
That feature is a poor man's session management for applications
that do not implement any specific session management features.
It badly interferes with proper session management support, so
applications must be able to disable it.
This enables fixing applications with
QGuiApplication::quitOnLastWindowClosed() true - the default -
dying too early, before they are enumerated for the list of
applications to restart on session restore, thus preventing them
from being restored. See
https://bugs.kde.org/show_bug.cgi?id=354724
[ChangeLog][QtGui] Qt asking to close windows on session exit as
a fallback session management mechanism has been made optional.
Disabling it fixes session management for applications that
implement full session management. See
QGuiApplication::isFallbackSessionManagementEnabled().
Task-number: QTBUG-49667
Change-Id: Ib22e58c9c64351dea8b7e2a74db91d26dd7ab7aa
Reviewed-by: Oswald Buddenhagen <oswald.buddenhagen@theqtcompany.com>
Reviewed-by: David Faure <david.faure@kdab.com>
---
.../mainwindows/application/mainwindow.cpp | 16 +++++
.../mainwindows/application/mainwindow.h | 2 +
.../code/src_gui_kernel_qguiapplication.cpp | 1 +
src/gui/kernel/qguiapplication.cpp | 60 ++++++++++++++++++-
src/gui/kernel/qguiapplication.h | 3 +
src/gui/kernel/qguiapplication_p.h | 1 +
src/gui/kernel/qsessionmanager.cpp | 19 +++---
7 files changed, 90 insertions(+), 12 deletions(-)
diff --git a/examples/widgets/mainwindows/application/mainwindow.cpp b/examples/widgets/mainwindows/application/mainwindow.cpp
index 86dfae166f3..861b908189d 100644
--- a/examples/widgets/mainwindows/application/mainwindow.cpp
+++ b/examples/widgets/mainwindows/application/mainwindow.cpp
@@ -59,6 +59,10 @@ MainWindow::MainWindow()
connect(textEdit->document(), &QTextDocument::contentsChanged,
this, &MainWindow::documentWasModified);
+ QGuiApplication::setFallbackSessionManagementEnabled(false);
+ connect(qApp, &QGuiApplication::commitDataRequest,
+ this, &MainWindow::commitData);
+
setCurrentFile(QString());
setUnifiedTitleAndToolBarOnMac(true);
}
@@ -383,3 +387,15 @@ QString MainWindow::strippedName(const QString &fullFileName)
return QFileInfo(fullFileName).fileName();
}
//! [49]
+
+void MainWindow::commitData(QSessionManager &manager)
+{
+ if (manager.allowsInteraction()) {
+ if (!maybeSave())
+ manager.cancel();
+ } else {
+ // Non-interactive: save without asking
+ if (textEdit->document()->isModified())
+ save();
+ }
+}
diff --git a/examples/widgets/mainwindows/application/mainwindow.h b/examples/widgets/mainwindows/application/mainwindow.h
index 08b4aa17f50..9712604125b 100644
--- a/examples/widgets/mainwindows/application/mainwindow.h
+++ b/examples/widgets/mainwindows/application/mainwindow.h
@@ -47,6 +47,7 @@ QT_BEGIN_NAMESPACE
class QAction;
class QMenu;
class QPlainTextEdit;
+class QSessionManager;
QT_END_NAMESPACE
//! [0]
@@ -69,6 +70,7 @@ private slots:
bool saveAs();
void about();
void documentWasModified();
+ void commitData(QSessionManager &);
private:
void createActions();
diff --git a/src/gui/doc/snippets/code/src_gui_kernel_qguiapplication.cpp b/src/gui/doc/snippets/code/src_gui_kernel_qguiapplication.cpp
index 4ddf8c8acbe..63fdb3bdd03 100644
--- a/src/gui/doc/snippets/code/src_gui_kernel_qguiapplication.cpp
+++ b/src/gui/doc/snippets/code/src_gui_kernel_qguiapplication.cpp
@@ -53,6 +53,7 @@ int main(int argc, char *argv[])
MyMainWidget::MyMainWidget(QWidget *parent)
:QWidget(parent)
{
+ QGuiApplication::setFallbackSessionManagementEnabled(false);
connect(qApp, SIGNAL(commitDataRequest(QSessionManager)), SLOT(commitData(QSessionManager)));
}
diff --git a/src/gui/kernel/qguiapplication.cpp b/src/gui/kernel/qguiapplication.cpp
index 65d679cdad5..8f1c62fbca2 100644
--- a/src/gui/kernel/qguiapplication.cpp
+++ b/src/gui/kernel/qguiapplication.cpp
@@ -138,6 +138,8 @@ QPlatformTheme *QGuiApplicationPrivate::platform_theme = 0;
QList<QObject *> QGuiApplicationPrivate::generic_plugin_list;
+bool QGuiApplicationPrivate::is_fallback_session_management_enabled = true;
+
enum ApplicationResourceFlags
{
ApplicationPaletteExplicitlySet = 0x1,
@@ -3082,6 +3084,55 @@ void QGuiApplicationPrivate::setApplicationState(Qt::ApplicationState state, boo
emit qApp->applicationStateChanged(applicationState);
}
+// ### Qt6: consider removing the feature or making it less intrusive
+/*!
+ \since 5.6
+
+ Returns whether QGuiApplication will use fallback session management.
+
+ The default is \c true.
+
+ If this is \c true and the session manager allows user interaction,
+ QGuiApplication will try to close toplevel windows after
+ commitDataRequest() has been emitted. If a window cannot be closed, session
+ shutdown will be canceled and the application will keep running.
+
+ Fallback session management only benefits applications that have an
+ "are you sure you want to close this window?" feature or other logic that
+ prevents closing a toplevel window depending on certain conditions, and
+ that do nothing to explicitly implement session management. In applications
+ that \e do implement session management using the proper session management
+ API, fallback session management interferes and may break session
+ management logic.
+
+ \warning If all windows \e are closed due to fallback session management
+ and quitOnLastWindowClosed() is \c true, the application will quit before
+ it is explicitly instructed to quit through the platform's session
+ management protocol. That violation of protocol may prevent the platform
+ session manager from saving application state.
+
+ \sa setFallbackSessionManagementEnabled(),
+ QSessionManager::allowsInteraction(), saveStateRequest(),
+ commitDataRequest(), {Session Management}
+*/
+bool QGuiApplication::isFallbackSessionManagementEnabled()
+{
+ return QGuiApplicationPrivate::is_fallback_session_management_enabled;
+}
+
+/*!
+ \since 5.6
+
+ Sets whether QGuiApplication will use fallback session management to
+ \a enabled.
+
+ \sa isFallbackSessionManagementEnabled()
+*/
+void QGuiApplication::setFallbackSessionManagementEnabled(bool enabled)
+{
+ QGuiApplicationPrivate::is_fallback_session_management_enabled = enabled;
+}
+
/*!
\since 4.2
\fn void QGuiApplication::commitDataRequest(QSessionManager &manager)
@@ -3106,7 +3157,8 @@ void QGuiApplicationPrivate::setApplicationState(Qt::ApplicationState state, boo
\note You should use Qt::DirectConnection when connecting to this signal.
- \sa isSessionRestored(), sessionId(), saveStateRequest(), {Session Management}
+ \sa setFallbackSessionManagementEnabled(), isSessionRestored(),
+ sessionId(), saveStateRequest(), {Session Management}
*/
/*!
@@ -3236,9 +3288,13 @@ void QGuiApplicationPrivate::commitData()
{
Q_Q(QGuiApplication);
is_saving_session = true;
+
emit q->commitDataRequest(*session_manager);
- if (session_manager->allowsInteraction() && !tryCloseAllWindows())
+ if (is_fallback_session_management_enabled && session_manager->allowsInteraction()
+ && !tryCloseAllWindows()) {
session_manager->cancel();
+ }
+
is_saving_session = false;
}
diff --git a/src/gui/kernel/qguiapplication.h b/src/gui/kernel/qguiapplication.h
index d995387d662..3f233d4edaf 100644
--- a/src/gui/kernel/qguiapplication.h
+++ b/src/gui/kernel/qguiapplication.h
@@ -152,6 +152,9 @@ public:
QString sessionId() const;
QString sessionKey() const;
bool isSavingSession() const;
+
+ static bool isFallbackSessionManagementEnabled();
+ static void setFallbackSessionManagementEnabled(bool);
#endif
static void sync();
diff --git a/src/gui/kernel/qguiapplication_p.h b/src/gui/kernel/qguiapplication_p.h
index 7c7da9790b4..4f0f6fdc443 100644
--- a/src/gui/kernel/qguiapplication_p.h
+++ b/src/gui/kernel/qguiapplication_p.h
@@ -234,6 +234,7 @@ public:
#endif
#ifndef QT_NO_SESSIONMANAGER
+ static bool is_fallback_session_management_enabled;
QSessionManager *session_manager;
bool is_session_restored;
bool is_saving_session;
diff --git a/src/gui/kernel/qsessionmanager.cpp b/src/gui/kernel/qsessionmanager.cpp
index f4b56fd01b7..c6d23f163cd 100644
--- a/src/gui/kernel/qsessionmanager.cpp
+++ b/src/gui/kernel/qsessionmanager.cpp
@@ -64,22 +64,21 @@ QT_BEGIN_NAMESPACE
settings.
QSessionManager provides an interface between the application and the
- session manager so that the program can work well with the session manager.
- In Qt, session management requests for action are handled by the two
- signals QGuiApplication::commitDataRequest() and
- QGuiApplication::saveStateRequest(). Both provide a reference to a session
- manager object as argument, to allow the application to communicate with
- the session manager. The session manager can only be accessed through these
- functions.
+ platform's session manager. In Qt, session management requests for action
+ are handled by the two signals QGuiApplication::commitDataRequest() and
+ QGuiApplication::saveStateRequest(). Both provide a reference to a
+ QSessionManager object as argument. The session manager can only be
+ accessed in slots invoked by these signals.
+
+ \warning If you use QSessionManager, you should disable fallback session
+ management: QGuiApplication::setFallbackSessionManagementEnabled().
No user interaction is possible \e unless the application gets explicit
permission from the session manager. You ask for permission by calling
allowsInteraction() or, if it is really urgent, allowsErrorInteraction().
Qt does not enforce this, but the session manager may.
- You can try to abort the shutdown process by calling cancel(). The default
- commitData() function does this if some top-level window rejected its
- closeEvent().
+ You can try to abort the shutdown process by calling cancel().
For sophisticated session managers provided on Unix/X11, QSessionManager
offers further possibilities to fine-tune an application's session
--
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