ClangCodeModel: Implement declaration/definition switch via clangd

Change-Id: I522a415d76fbc5332e5cc1fdfd2d7ab19cb9ed64
Reviewed-by: David Schulz <david.schulz@qt.io>

2 files changed, 135 insertions, 78 deletions

diff --git a/src/plugins/cppeditor/cppeditorwidget.cpp b/src/plugins/cppeditor/cppeditorwidget.cpp
index 7e48d545456..7083707b6d7 100644
--- a/src/plugins/cppeditor/cppeditorwidget.cpp
+++ b/src/plugins/cppeditor/cppeditorwidget.cpp
@@ -711,78 +711,15 @@ void CppEditorWidget::switchDeclarationDefinition(bool inNextSplit)
     if (!d->m_modelManager)
         return;
 
-    if (!d->m_lastSemanticInfo.doc)
-        return;
-
-    // Find function declaration or definition under cursor
-    Function *functionDefinitionSymbol = nullptr;
-    Symbol *functionDeclarationSymbol = nullptr;
-    Symbol *declarationSymbol = nullptr;
-
-    ASTPath astPathFinder(d->m_lastSemanticInfo.doc);
-    const QList<AST *> astPath = astPathFinder(textCursor());
-
-    for (AST *ast : astPath) {
-        if (FunctionDefinitionAST *functionDefinitionAST = ast->asFunctionDefinition()) {
-            if ((functionDefinitionSymbol = functionDefinitionAST->symbol))
-                break; // Function definition found!
-        } else if (SimpleDeclarationAST *simpleDeclaration = ast->asSimpleDeclaration()) {
-            if (List<Symbol *> *symbols = simpleDeclaration->symbols) {
-                if (Symbol *symbol = symbols->value) {
-                    if (symbol->isDeclaration()) {
-                        declarationSymbol = symbol;
-                        if (symbol->type()->isFunctionType()) {
-                            functionDeclarationSymbol = symbol;
-                            break; // Function declaration found!
-                        }
-                    }
-                }
-            }
-        }
-    }
-
-    // Link to function definition/declaration
-    Utils::Link symbolLink;
-    if (functionDeclarationSymbol) {
-        Symbol *symbol = d->m_modelManager->symbolFinder()
-                ->findMatchingDefinition(functionDeclarationSymbol, d->m_modelManager->snapshot());
-        if (symbol)
-            symbolLink = symbol->toLink();
-    } else if (declarationSymbol) {
-        Symbol *symbol = d->m_modelManager->symbolFinder()
-                ->findMatchingVarDefinition(declarationSymbol, d->m_modelManager->snapshot());
-        if (symbol)
-            symbolLink = symbol->toLink();
-    } else if (functionDefinitionSymbol) {
-        const Snapshot snapshot = d->m_modelManager->snapshot();
-        LookupContext context(d->m_lastSemanticInfo.doc, snapshot);
-        ClassOrNamespace *binding = context.lookupType(functionDefinitionSymbol);
-        const QList<LookupItem> declarations
-            = context.lookup(functionDefinitionSymbol->name(),
-                             functionDefinitionSymbol->enclosingScope());
-
-        QList<Symbol *> best;
-        foreach (const LookupItem &r, declarations) {
-            if (Symbol *decl = r.declaration()) {
-                if (Function *funTy = decl->type()->asFunctionType()) {
-                    if (funTy->match(functionDefinitionSymbol)) {
-                        if (decl != functionDefinitionSymbol && binding == r.binding())
-                            best.prepend(decl);
-                        else
-                            best.append(decl);
-                    }
-                }
-            }
-        }
-
-        if (best.isEmpty())
-            return;
-        symbolLink = best.first()->toLink();
-    }
-
-    // Open Editor at link position
-    if (symbolLink.hasValidTarget())
-        openLink(symbolLink, inNextSplit != alwaysOpenLinksInNextSplit());
+    const CursorInEditor cursor(textCursor(), textDocument()->filePath(), this, textDocument());
+    auto callback = [self = QPointer(this),
+            split = inNextSplit != alwaysOpenLinksInNextSplit()](const Link &link) {
+        if (self && link.hasValidTarget())
+            self->openLink(link, split);
+    };
+    followSymbolInterface().switchDeclDef(cursor, std::move(callback),
+                                          d->m_modelManager->snapshot(), d->m_lastSemanticInfo.doc,
+                                          d->m_modelManager->symbolFinder());
 }
 
 void CppEditorWidget::findLinkAt(const QTextCursor &cursor,
diff --git a/src/plugins/cppeditor/followsymbol_switchmethoddecldef_test.cpp b/src/plugins/cppeditor/followsymbol_switchmethoddecldef_test.cpp
index 401a7eb39fa..5eefae1e02c 100644
--- a/src/plugins/cppeditor/followsymbol_switchmethoddecldef_test.cpp
+++ b/src/plugins/cppeditor/followsymbol_switchmethoddecldef_test.cpp
@@ -297,14 +297,12 @@ F2TestCase::F2TestCase(CppEditorAction action,
             QSKIP("fuzzy matching is not supposed to work with clangd"); // TODO: Implement fallback as we do with libclang
         if (tag == "baseClassFunctionIntroducedByUsingDeclaration")
             QSKIP("clangd points to the using declaration");
-        if (tag == "classDestructor")
+        if (tag == "classDestructor" || tag == "fromDestructorDefinitionSymbol"
+                || tag == "fromDestructorBody") {
             QSKIP("clangd wants the cursor before the ~ character");
+        }
         if (curTestName == "test_FollowSymbolUnderCursor_classOperator_inOp")
             QSKIP("clangd goes to operator name first");
-        if (tag == "fromFunctionBody" || tag == "fromReturnType"
-                || tag == "conversionOperatorDecl2Def") {
-            QSKIP("TODO: explicit decl/def switch not yet supported with clangd");
-        }
     }
 
     // Write files to disk
@@ -415,7 +413,9 @@ F2TestCase::F2TestCase(CppEditorAction action,
         break;
     }
     case SwitchBetweenMethodDeclarationDefinitionAction:
-        if (CppTools::codeModelSettings()->useClangd())
+        // Some test cases were erroneously added as decl/def, but they are really
+        // follow symbol functionality (in commit a0764603d0).
+        if (useClangd && tag.endsWith("Var"))
             initialTestFile->m_editorWidget->openLinkUnderCursor();
         else
             CppEditorPlugin::instance()->switchDeclarationDefinition();
@@ -623,6 +623,126 @@ void CppEditorPlugin::test_SwitchMethodDeclarationDefinition_data()
         "}\n"                   // Line 10
     );
 
+    QTest::newRow("fromConstructorDeclarationSymbol") << _(
+        "class C\n"
+        "{\n"
+        "public:\n"
+        "    C();\n"
+        "    int @function();\n"  // Line 5
+        "};\n"
+        ) << _(
+        "#include \"file.h\"\n"
+        "\n"
+        "C::C()\n"
+        "{\n"
+        "}\n"                   // Line 5
+        "\n"
+        "int C::$function()\n"
+        "{\n"
+        "    return 1 + 1;\n"
+        "}\n"                   // Line 10
+        );
+
+    QTest::newRow("fromConstructorDefinitionSymbol") << _(
+        "class C\n"
+        "{\n"
+        "public:\n"
+        "    $C();\n"
+        "    int function();\n"
+        "};\n"
+        ) << _(
+        "#include \"file.h\"\n"
+        "\n"
+        "C::@C()\n"
+        "{\n"
+        "}\n"
+        "\n"
+        "int C::function()\n"
+        "{\n"
+        "    return 1 + 1;\n"
+        "}\n"
+        );
+
+    QTest::newRow("fromConstructorBody") << _(
+        "class C\n"
+        "{\n"
+        "public:\n"
+        "    $C();\n"
+        "    int function();\n"
+        "};\n"
+        ) << _(
+        "#include \"file.h\"\n"
+        "\n"
+        "C::C()\n"
+        "{@\n"
+        "}\n"                   // Line 5
+        "\n"
+        "int C::function()\n"
+        "{\n"
+        "    return 1 + 1;\n"
+        "}\n"                   // Line 10
+        );
+
+    QTest::newRow("fromDestructorDeclarationSymbol") << _(
+        "class C\n"
+        "{\n"
+        "public:\n"
+        "    @C();\n"
+        "    int function();\n"  // Line 5
+        "};\n"
+        ) << _(
+        "#include \"file.h\"\n"
+        "\n"
+        "C::$C()\n"
+        "{\n"
+        "}\n"                   // Line 5
+        "\n"
+        "int C::function()\n"
+        "{\n"
+        "    return 1 + 1;\n"
+        "}\n"                   // Line 10
+        );
+
+    QTest::newRow("fromDestructorDefinitionSymbol") << _(
+        "class C\n"
+        "{\n"
+        "public:\n"
+        "    ~$C();\n"
+        "    int function();\n"
+        "};\n"
+        ) << _(
+        "#include \"file.h\"\n"
+        "\n"
+        "C::@~C()\n"
+        "{\n"
+        "}\n"
+        "\n"
+        "int C::function()\n"
+        "{\n"
+        "    return 1 + 1;\n"
+        "}\n"
+        );
+
+    QTest::newRow("fromDestructorBody") << _(
+        "class C\n"
+        "{\n"
+        "public:\n"
+        "    ~$C();\n"
+        "    int function();\n"
+        "};\n"
+        ) << _(
+        "#include \"file.h\"\n"
+        "\n"
+        "C::~C()\n"
+        "{@\n"
+        "}\n"                   // Line 5
+        "\n"
+        "int C::function()\n"
+        "{\n"
+        "    return 1 + 1;\n"
+        "}\n"                   // Line 10
+        );
+
     QTest::newRow("fromReturnType") << _(
         "class C\n"
         "{\n"