CppEditor: Adapt function declaration

... when changing the name of a function parameter from a point of use,
rather than from the definition.
The normal function decl/def link mechanism only covers editing in the
signature.

Task-number: QTCREATORBUG-29925
Change-Id: I34ff90117685184b9fc72937b401976274f4876c
Reviewed-by: Christian Stenger <christian.stenger@qt.io>
Reviewed-by: <github-actions-qt-creator@cristianadam.eu>

7 files changed, 146 insertions, 2 deletions

diff --git a/src/plugins/cppeditor/CMakeLists.txt b/src/plugins/cppeditor/CMakeLists.txt
index 49fe02c17e..66e25f08fe 100644
--- a/src/plugins/cppeditor/CMakeLists.txt
+++ b/src/plugins/cppeditor/CMakeLists.txt
@@ -48,6 +48,7 @@ add_qtc_plugin(CppEditor
     cppfindreferences.cpp cppfindreferences.h
     cppfollowsymbolundercursor.cpp cppfollowsymbolundercursor.h
     cppfunctiondecldeflink.cpp cppfunctiondecldeflink.h
+    cppfunctionparamrenaminghandler.cpp cppfunctionparamrenaminghandler.h
     cpphighlighter.cpp cpphighlighter.h
     cppincludehierarchy.cpp cppincludehierarchy.h
     cppincludesfilter.cpp cppincludesfilter.h
diff --git a/src/plugins/cppeditor/cppeditor.qbs b/src/plugins/cppeditor/cppeditor.qbs
index 45a7901817..2e8581a50c 100644
--- a/src/plugins/cppeditor/cppeditor.qbs
+++ b/src/plugins/cppeditor/cppeditor.qbs
@@ -108,6 +108,8 @@ QtcPlugin {
         "cppfollowsymbolundercursor.h",
         "cppfunctiondecldeflink.cpp",
         "cppfunctiondecldeflink.h",
+        "cppfunctionparamrenaminghandler.cpp",
+        "cppfunctionparamrenaminghandler.h",
         "cpphighlighter.cpp",
         "cpphighlighter.h",
         "cppincludehierarchy.cpp",
@@ -226,7 +228,7 @@ QtcPlugin {
         "symbolsfindfilter.h",
         "typehierarchybuilder.cpp",
         "typehierarchybuilder.h",
-        "wrappablelineedit.cpp", // FIXME: Is this used?
+        "wrappablelineedit.cpp",
         "wrappablelineedit.h",
     ]
 
diff --git a/src/plugins/cppeditor/cppeditorwidget.cpp b/src/plugins/cppeditor/cppeditorwidget.cpp
index dd49bbec90..aa112e0b48 100644
--- a/src/plugins/cppeditor/cppeditorwidget.cpp
+++ b/src/plugins/cppeditor/cppeditorwidget.cpp
@@ -11,13 +11,13 @@
 #include "cppeditorplugin.h"
 #include "cppeditortr.h"
 #include "cppfunctiondecldeflink.h"
+#include "cppfunctionparamrenaminghandler.h"
 #include "cpplocalrenaming.h"
 #include "cppmodelmanager.h"
 #include "cpppreprocessordialog.h"
 #include "cppquickfixassistant.h"
 #include "cppselectionchanger.h"
 #include "cppsemanticinfo.h"
-#include "cpptoolssettings.h"
 #include "cppuseselectionsupdater.h"
 #include "doxygengenerator.h"
 
@@ -396,6 +396,7 @@ public:
     QToolButton *m_preprocessorButton = nullptr;
 
     CppLocalRenaming m_localRenaming;
+    CppFunctionParamRenamingHandler m_paramRenamingHandler;
     CppUseSelectionsUpdater m_useSelectionsUpdater;
     CppSelectionChanger m_cppSelectionChanger;
     bool inTestMode = false;
@@ -405,6 +406,7 @@ CppEditorWidgetPrivate::CppEditorWidgetPrivate(CppEditorWidget *q)
     : m_cppEditorDocument(qobject_cast<CppEditorDocument *>(q->textDocument()))
     , m_declDefLinkFinder(new FunctionDeclDefLinkFinder(q))
     , m_localRenaming(q)
+    , m_paramRenamingHandler(*q, m_localRenaming)
     , m_useSelectionsUpdater(q)
     , m_cppSelectionChanger()
 {}
diff --git a/src/plugins/cppeditor/cppfunctionparamrenaminghandler.cpp b/src/plugins/cppeditor/cppfunctionparamrenaminghandler.cpp
new file mode 100644
index 0000000000..092e216b2d
--- /dev/null
+++ b/src/plugins/cppeditor/cppfunctionparamrenaminghandler.cpp
@@ -0,0 +1,112 @@
+// Copyright (C) 2023 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0-only WITH Qt-GPL-exception-1.0
+
+#include "cppfunctionparamrenaminghandler.h"
+
+#include "cppeditorwidget.h"
+#include "cpplocalrenaming.h"
+#include "cppfunctiondecldeflink.h"
+
+#include <cplusplus/AST.h>
+#include <cplusplus/ASTPath.h>
+#include <texteditor/textdocument.h>
+
+#include <memory>
+
+using namespace CPlusPlus;
+
+namespace CppEditor::Internal {
+
+using DeclDefLinkPtr = QSharedPointer<FunctionDeclDefLink>;
+
+class CppFunctionParamRenamingHandler::Private
+{
+public:
+    Private(CppEditorWidget &editorWidget, CppLocalRenaming &localRenaming);
+
+    void handleRenamingStarted();
+    void handleRenamingFinished();
+    void handleLinkFound(const DeclDefLinkPtr &link);
+    void findLink(FunctionDefinitionAST &func, const SemanticInfo &semanticInfo);
+
+    CppEditorWidget &editorWidget;
+    CppLocalRenaming &localRenaming;
+    std::unique_ptr<FunctionDeclDefLinkFinder> linkFinder;
+    DeclDefLinkPtr link;
+};
+
+CppFunctionParamRenamingHandler::CppFunctionParamRenamingHandler(
+    CppEditorWidget &editorWidget, CppLocalRenaming &localRenaming)
+    : d(new Private(editorWidget, localRenaming)) {}
+
+CppFunctionParamRenamingHandler::~CppFunctionParamRenamingHandler() { delete d; }
+
+CppFunctionParamRenamingHandler::Private::Private(
+    CppEditorWidget &editorWidget, CppLocalRenaming &localRenaming)
+    : editorWidget(editorWidget), localRenaming(localRenaming)
+{
+    QObject::connect(&localRenaming, &CppLocalRenaming::started,
+                     &editorWidget, [this] { handleRenamingStarted(); });
+    QObject::connect(&localRenaming, &CppLocalRenaming::finished,
+                     &editorWidget, [this] { handleRenamingFinished(); });
+}
+
+void CppFunctionParamRenamingHandler::Private::handleRenamingStarted()
+{
+    linkFinder.reset();
+    link.clear();
+
+    // Are we currently on the function signature? In this case, the normal decl/def link
+    // mechanism kicks in and we don't have to do anything.
+    if (editorWidget.declDefLink())
+        return;
+
+    // If we find a surrounding function definition, start up the decl/def link finder.
+    const SemanticInfo semanticInfo = editorWidget.semanticInfo();
+    if (!semanticInfo.doc || !semanticInfo.doc->translationUnit())
+        return;
+    const QList<AST *> astPath = ASTPath(semanticInfo.doc)(editorWidget.textCursor());
+    for (auto it = astPath.rbegin(); it != astPath.rend(); ++it) {
+        if (const auto func = (*it)->asFunctionDefinition()) {
+            findLink(*func, semanticInfo);
+            return;
+        }
+    }
+}
+
+void CppFunctionParamRenamingHandler::Private::handleRenamingFinished()
+{
+    if (link) {
+        link->apply(&editorWidget, false);
+        link.clear();
+    }
+}
+
+void CppFunctionParamRenamingHandler::Private::handleLinkFound(const DeclDefLinkPtr &link)
+{
+    if (localRenaming.isActive())
+        this->link = link;
+    linkFinder.reset();
+}
+
+void CppFunctionParamRenamingHandler::Private::findLink(FunctionDefinitionAST &func,
+                                                        const SemanticInfo &semanticInfo)
+{
+    if (!func.declarator)
+        return;
+
+    // The finder needs a cursor that points to the signature, so provide one.
+    QTextDocument * const doc = editorWidget.textDocument()->document();
+    const int pos = semanticInfo.doc->translationUnit()->getTokenEndPositionInDocument(
+        func.declarator->firstToken(), doc);
+    QTextCursor cursor(doc);
+    cursor.setPosition(pos);
+    linkFinder.reset(new FunctionDeclDefLinkFinder);
+    QObject::connect(linkFinder.get(), &FunctionDeclDefLinkFinder::foundLink,
+            &editorWidget, [this](const DeclDefLinkPtr &link) {
+        handleLinkFound(link);
+    });
+    linkFinder->startFindLinkAt(cursor, semanticInfo.doc, semanticInfo.snapshot);
+}
+
+} // namespace CppEditor::Internal
diff --git a/src/plugins/cppeditor/cppfunctionparamrenaminghandler.h b/src/plugins/cppeditor/cppfunctionparamrenaminghandler.h
new file mode 100644
index 0000000000..e923855ca6
--- /dev/null
+++ b/src/plugins/cppeditor/cppfunctionparamrenaminghandler.h
@@ -0,0 +1,25 @@
+// Copyright (C) 2023 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0-only WITH Qt-GPL-exception-1.0
+
+#pragma once
+
+namespace CppEditor {
+class CppEditorWidget;
+
+namespace Internal {
+class CppLocalRenaming;
+
+// Watches local renamings and adapts the declaration if a function parameter was renamed.
+class CppFunctionParamRenamingHandler
+{
+public:
+    CppFunctionParamRenamingHandler(CppEditorWidget &editorWidget, CppLocalRenaming &localRenaming);
+    ~CppFunctionParamRenamingHandler();
+
+private:
+    class Private;
+    Private * const d;
+};
+
+} // namespace Internal
+} // namespace CppEditor
diff --git a/src/plugins/cppeditor/cpplocalrenaming.cpp b/src/plugins/cppeditor/cpplocalrenaming.cpp
index f23b9d80a6..5bad16a0b6 100644
--- a/src/plugins/cppeditor/cpplocalrenaming.cpp
+++ b/src/plugins/cppeditor/cpplocalrenaming.cpp
@@ -62,6 +62,7 @@ bool CppLocalRenaming::start()
         updateRenamingSelectionFormat(textCharFormat(TextEditor::C_OCCURRENCES_RENAME));
         m_firstRenameChangeExpected = true;
         updateEditorWidgetWithSelections();
+        emit started();
         return true;
     }
 
diff --git a/src/plugins/cppeditor/cpplocalrenaming.h b/src/plugins/cppeditor/cpplocalrenaming.h
index 082d4648a8..56ff153044 100644
--- a/src/plugins/cppeditor/cpplocalrenaming.h
+++ b/src/plugins/cppeditor/cpplocalrenaming.h
@@ -41,6 +41,7 @@ public:
     bool isSameSelection(int cursorPosition) const;
 
 signals:
+    void started();
     void finished();
     void processKeyPressNormally(QKeyEvent *e);