Core: allow multiple contexts per widget

This makes it possible to allow different sets of actions for a specific
widget depending on the defined contexts for that widget.

Fixes: QTCREATORBUG-30675
Fixes: QTCREATORBUG-30677
Change-Id: I408e0ae445b364d4f450ccdd2fbdfc81ece45015
Reviewed-by: Eike Ziller <eike.ziller@qt.io>

src/plugins/coreplugin/icore.cpp

@@ -314,7 +314,7 @@ public:
 
     QList<IContext *> m_activeContext;
 
-    std::unordered_map<QWidget *, IContext *> m_contextWidgets;
+    std::unordered_map<QWidget *, QList<IContext *>> m_contextWidgets;
 
     ShortcutSettings *m_shortcutSettings = nullptr;
     ToolSettings *m_toolSettings = nullptr;
@@ -836,16 +836,18 @@ QString ICore::versionString()
 }
 
 /*!
-    Returns the top level IContext of the current context, or \c nullptr if
+    Returns a list IContexts for the current top level context widget, or an empty list if
     there is none.
 
     \sa updateAdditionalContexts()
     \sa addContextObject()
     \sa {The Action Manager and Commands}
 */
-IContext *ICore::currentContextObject()
+QList<IContext *> ICore::currentContextObjects()
 {
-    return d->m_activeContext.isEmpty() ? nullptr : d->m_activeContext.first();
+    if (d->m_activeContext.isEmpty())
+        return {};
+    return d->m_contextWidgets[d->m_activeContext.first()->widget()];
 }
 
 /*!
@@ -856,8 +858,7 @@ IContext *ICore::currentContextObject()
 */
 QWidget *ICore::currentContextWidget()
 {
-    IContext *context = currentContextObject();
-    return context ? context->widget() : nullptr;
+    return d->m_activeContext.isEmpty() ? nullptr : d->m_activeContext.first()->widget();
 }
 
 /*!
@@ -1525,8 +1526,10 @@ void ICore::extensionsInitialized()
 void ICore::aboutToShutdown()
 {
     disconnect(qApp, &QApplication::focusChanged, d, &ICorePrivate::updateFocusWidget);
-    for (auto contextPair : d->m_contextWidgets)
-        disconnect(contextPair.second, &QObject::destroyed, d->m_mainwindow, nullptr);
+    for (auto contextsPair : d->m_contextWidgets) {
+        for (auto context : contextsPair.second)
+            disconnect(context, &QObject::destroyed, d->m_mainwindow, nullptr);
+    }
     d->m_activeContext.clear();
     d->m_mainwindow->hide();
 }
@@ -2281,13 +2284,14 @@ void ICore::openFileWith()
 }
 
 /*!
-    Returns the registered IContext instance for the specified \a widget,
+    Returns all registered IContext instance for the specified \a widget,
     if any.
 */
-IContext *ICore::contextObject(QWidget *widget)
+QList<IContext *> ICore::contextObjects(QWidget *widget)
 {
-    const auto it = d->m_contextWidgets.find(widget);
-    return it == d->m_contextWidgets.end() ? nullptr : it->second;
+    if (auto it = d->m_contextWidgets.find(widget); it != d->m_contextWidgets.end())
+        return it->second;
+    return {};
 }
 
 /*!
@@ -2306,11 +2310,7 @@ void ICore::addContextObject(IContext *context)
 {
     if (!context)
         return;
-    QWidget *widget = context->widget();
-    if (d->m_contextWidgets.find(widget) != d->m_contextWidgets.end())
-        return;
-
-    d->m_contextWidgets.insert({widget, context});
+    d->m_contextWidgets[context->widget()].append(context);
     connect(context, &QObject::destroyed, m_core, [context] { removeContextObject(context); });
 }
 
@@ -2331,15 +2331,19 @@ void ICore::removeContextObject(IContext *context)
 
     disconnect(context, &QObject::destroyed, m_core, nullptr);
 
-    const auto it = std::find_if(d->m_contextWidgets.cbegin(),
-                                 d->m_contextWidgets.cend(),
-                                 [context](const std::pair<QWidget *, IContext *> &v) {
-                                     return v.second == context;
-                                 });
-    if (it == d->m_contextWidgets.cend())
+    auto it = std::find_if(
+        d->m_contextWidgets.begin(),
+        d->m_contextWidgets.end(),
+        [context](const std::pair<QWidget *, QList<IContext *>> &v) {
+            return v.second.contains(context);
+        });
+    if (it == d->m_contextWidgets.end())
         return;
 
-    d->m_contextWidgets.erase(it);
+    it->second.removeAll(context);
+    if (it->second.isEmpty())
+        d->m_contextWidgets.erase(it);
+
     if (d->m_activeContext.removeAll(context) > 0)
         d->updateContextObject(d->m_activeContext);
 }
@@ -2355,15 +2359,8 @@ void ICorePrivate::updateFocusWidget(QWidget *old, QWidget *now)
         return;
 
     QList<IContext *> newContext;
-    if (QWidget *p = QApplication::focusWidget()) {
-        IContext *context = nullptr;
-        while (p) {
-            context = ICore::contextObject(p);
-            if (context)
-                newContext.append(context);
-            p = p->parentWidget();
-        }
-    }
+    for (QWidget *p = QApplication::focusWidget(); p; p = p->parentWidget())
+        newContext.append(ICore::contextObjects(p));
 
     // ignore toplevels that define no context, like popups without parent
     if (!newContext.isEmpty() || QApplication::focusWidget() == m_mainwindow->focusWidget())