CplusPlus: Use plainer callbacks to interact to the CppEditor

Lets us remove a few explicit CppModelManager::instance() call
in user code later.

Change-Id: Id8d846d06a0715b3d609cc5d52cc031e1d025fb1
Reviewed-by: Christian Kandeler <christian.kandeler@qt.io>

5 files changed, 70 insertions, 54 deletions

diff --git a/src/libs/cplusplus/cppmodelmanagerbase.cpp b/src/libs/cplusplus/cppmodelmanagerbase.cpp
index c869fd61a0..cff9ef99e2 100644
--- a/src/libs/cplusplus/cppmodelmanagerbase.cpp
+++ b/src/libs/cplusplus/cppmodelmanagerbase.cpp
@@ -3,48 +3,57 @@
 
 #include "cppmodelmanagerbase.h"
 
-namespace CPlusPlus {
+#include <utils/qtcassert.h>
 
-static CppModelManagerBase *g_instance = nullptr;
+namespace CPlusPlus::CppModelManagerBase {
 
-CppModelManagerBase::CppModelManagerBase(QObject *parent)
-    : QObject(parent)
+static bool (*setExtraDiagnosticsCallback)
+    (const QString &, const QString &, const QList<Document::DiagnosticMessage> &) = nullptr;
+
+static CPlusPlus::Snapshot (*snapshotCallback)() = nullptr;
+
+
+bool trySetExtraDiagnostics(const QString &fileName, const QString &kind,
+                            const QList<Document::DiagnosticMessage> &diagnostics)
 {
-    Q_ASSERT(!g_instance);
-    g_instance = this;
+    if (!setExtraDiagnosticsCallback)
+        return false;
+    return setExtraDiagnosticsCallback(fileName, kind, diagnostics);
 }
 
-CppModelManagerBase::~CppModelManagerBase()
+bool setExtraDiagnostics(const QString &fileName, const QString &kind,
+                            const QList<Document::DiagnosticMessage> &diagnostics)
 {
-    Q_ASSERT(g_instance == this);
-    g_instance = nullptr;
+    QTC_ASSERT(setExtraDiagnosticsCallback, return false);
+    return setExtraDiagnosticsCallback(fileName, kind, diagnostics);
 }
 
-CppModelManagerBase *CppModelManagerBase::instance()
+Snapshot snapshot()
 {
-    return g_instance;
+    QTC_ASSERT(snapshotCallback, return {});
+    return snapshotCallback();
 }
 
-bool CppModelManagerBase::trySetExtraDiagnostics(const QString &fileName, const QString &kind,
-                                                 const QList<CPlusPlus::Document::DiagnosticMessage> &diagnostics)
+bool hasSnapshots()
 {
-    if (CppModelManagerBase *mm = instance())
-        return mm->setExtraDiagnostics(fileName, kind, diagnostics);
-    return false;
+    return snapshotCallback;
 }
 
-bool CppModelManagerBase::setExtraDiagnostics(const QString &fileName, const QString &kind,
-                                              const QList<CPlusPlus::Document::DiagnosticMessage> &diagnostics)
+// Installation
+
+void registerSetExtraDiagnosticsCallback(
+    bool (*callback)(const QString &, const QString &, const QList<Document::DiagnosticMessage> &))
 {
-    Q_UNUSED(fileName)
-    Q_UNUSED(kind)
-    Q_UNUSED(diagnostics)
-    return false;
+    QTC_ASSERT(callback, return);
+    QTC_CHECK(!setExtraDiagnosticsCallback); // bark when used twice
+    setExtraDiagnosticsCallback = callback;
 }
 
-CPlusPlus::Snapshot CppModelManagerBase::snapshot() const
+void registerSnapshotCallback(Snapshot (*callback)())
 {
-    return CPlusPlus::Snapshot();
+    QTC_ASSERT(callback, return);
+    QTC_CHECK(!snapshotCallback); // bark when used twice
+    snapshotCallback = callback;
 }
 
-} // namespace CPlusPlus
+} // CPlusPlus::CppModelManagerBase
diff --git a/src/libs/cplusplus/cppmodelmanagerbase.h b/src/libs/cplusplus/cppmodelmanagerbase.h
index d003fcf1de..1a9e4c7db3 100644
--- a/src/libs/cplusplus/cppmodelmanagerbase.h
+++ b/src/libs/cplusplus/cppmodelmanagerbase.h
@@ -5,29 +5,24 @@
 
 #include <cplusplus/CppDocument.h>
 
-#include <QObject>
-#include <QList>
+namespace CPlusPlus::CppModelManagerBase {
 
-QT_BEGIN_NAMESPACE
-class QString;
-QT_END_NAMESPACE
+CPLUSPLUS_EXPORT bool trySetExtraDiagnostics
+    (const QString &, const QString &, const QList<Document::DiagnosticMessage> &);
 
-namespace CPlusPlus {
+CPLUSPLUS_EXPORT bool setSetExtraDiagnostics
+    (const QString &, const QString &, const QList<Document::DiagnosticMessage> &);
 
-class CPLUSPLUS_EXPORT CppModelManagerBase : public QObject
-{
-    Q_OBJECT
-public:
-    CppModelManagerBase(QObject *parent = nullptr);
-    ~CppModelManagerBase();
+CPLUSPLUS_EXPORT bool hasSnapshots();
 
-    static CppModelManagerBase *instance();
-    static bool trySetExtraDiagnostics(const QString &fileName, const QString &kind,
-                                       const QList<Document::DiagnosticMessage> &diagnostics);
+CPLUSPLUS_EXPORT CPlusPlus::Snapshot snapshot();
 
-    virtual bool setExtraDiagnostics(const QString &fileName, const QString &kind,
-                                     const QList<Document::DiagnosticMessage> &diagnostics);
-    virtual CPlusPlus::Snapshot snapshot() const;
-};
 
-} // namespace CPlusPlus
+// These callback are provided by the CppEditor plugin.
+
+CPLUSPLUS_EXPORT void registerSnapshotCallback(CPlusPlus::Snapshot (*)(void));
+
+CPLUSPLUS_EXPORT void registerSetExtraDiagnosticsCallback(
+    bool(*)(const QString &, const QString &, const QList<Document::DiagnosticMessage> &));
+
+} // CPlusPlus::CppModelManagerBase
diff --git a/src/libs/qmljs/qmljsmodelmanagerinterface.cpp b/src/libs/qmljs/qmljsmodelmanagerinterface.cpp
index 93b8ca35e7..26238807e0 100644
--- a/src/libs/qmljs/qmljsmodelmanagerinterface.cpp
+++ b/src/libs/qmljs/qmljsmodelmanagerinterface.cpp
@@ -1366,13 +1366,12 @@ void ModelManagerInterface::startCppQmlTypeUpdate()
         return;
     }
 
-    CPlusPlus::CppModelManagerBase *cppModelManager =
-            CPlusPlus::CppModelManagerBase::instance();
-    if (!cppModelManager)
+    if (!CPlusPlus::CppModelManagerBase::hasSnapshots())
         return;
 
     m_cppQmlTypesUpdater = Utils::asyncRun(&ModelManagerInterface::updateCppQmlTypes, this,
-                                           cppModelManager->snapshot(), m_queuedCppDocuments);
+                                           CPlusPlus::CppModelManagerBase::snapshot(),
+                                           m_queuedCppDocuments);
     m_queuedCppDocuments.clear();
 }
 
diff --git a/src/plugins/cppeditor/cppmodelmanager.cpp b/src/plugins/cppeditor/cppmodelmanager.cpp
index 4ea3e99edf..7fb8115873 100644
--- a/src/plugins/cppeditor/cppmodelmanager.cpp
+++ b/src/plugins/cppeditor/cppmodelmanager.cpp
@@ -912,12 +912,25 @@ void CppModelManager::initCppTools()
     });
 }
 
+static bool setExtraDiagnosticsCallback(const QString &fileName, const QString &kind,
+                                     const QList<Document::DiagnosticMessage> &diagnostics)
+{
+    return m_instance->setExtraDiagnostics(fileName, kind, diagnostics);
+}
+
+static Snapshot snapshotCallback()
+{
+    return m_instance->snapshot();
+}
+
 CppModelManager::CppModelManager()
-    : CppModelManagerBase(nullptr)
-    , d(new CppModelManagerPrivate)
+    : d(new CppModelManagerPrivate)
 {
     m_instance = this;
 
+    CppModelManagerBase::registerSetExtraDiagnosticsCallback(&setExtraDiagnosticsCallback);
+    CppModelManagerBase::registerSnapshotCallback(&snapshotCallback);
+
     // Used for weak dependency in VcsBaseSubmitEditor
     setObjectName("CppModelManager");
     ExtensionSystem::PluginManager::addObject(this);
diff --git a/src/plugins/cppeditor/cppmodelmanager.h b/src/plugins/cppeditor/cppmodelmanager.h
index 3ab9ee2689..7dd49c6ebd 100644
--- a/src/plugins/cppeditor/cppmodelmanager.h
+++ b/src/plugins/cppeditor/cppmodelmanager.h
@@ -66,7 +66,7 @@ enum class SignalSlotType {
     None
 };
 
-class CPPEDITOR_EXPORT CppModelManager final : public CPlusPlus::CppModelManagerBase
+class CPPEDITOR_EXPORT CppModelManager final : public QObject
 {
     Q_OBJECT
 
@@ -97,7 +97,7 @@ public:
 
     bool setExtraDiagnostics(const QString &fileName,
                              const QString &kind,
-                             const QList<Document::DiagnosticMessage> &diagnostics) override;
+                             const QList<Document::DiagnosticMessage> &diagnostics);
 
     const QList<Document::DiagnosticMessage> diagnosticMessages();
 
@@ -119,7 +119,7 @@ public:
     ///         all loaded projects.
     ProjectPart::ConstPtr fallbackProjectPart();
 
-    CPlusPlus::Snapshot snapshot() const override;
+    CPlusPlus::Snapshot snapshot() const;
     Document::Ptr document(const Utils::FilePath &filePath) const;
     bool replaceDocument(Document::Ptr newDoc);