ClangCodeModel: Move decl/def switch functionality to dedicated class

Change-Id: Id583ac58933e35e979083311907331b627d3c067
Reviewed-by: David Schulz <david.schulz@qt.io>

src/plugins/clangcodemodel/clangdswitchdecldef.cpp

@@ -0,0 +1,188 @@
+/****************************************************************************
+**
+** Copyright (C) 2022 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of Qt Creator.
+**
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** GNU General Public License Usage
+** Alternatively, this file may be used under the terms of the GNU
+** General Public License version 3 as published by the Free Software
+** Foundation with exceptions as appearing in the file LICENSE.GPL3-EXCEPT
+** included in the packaging of this file. Please review the following
+** information to ensure the GNU General Public License requirements will
+** be met: https://www.gnu.org/licenses/gpl-3.0.html.
+**
+****************************************************************************/
+
+#include "clangdswitchdecldef.h"
+
+#include "clangdast.h"
+#include "clangdclient.h"
+
+#include <cppeditor/cppeditorwidget.h>
+#include <languageclient/documentsymbolcache.h>
+#include <languageserverprotocol/lsptypes.h>
+#include <texteditor/textdocument.h>
+#include <utils/optional.h>
+#include <utils/qtcassert.h>
+
+#include <QApplication>
+#include <QTextCursor>
+
+using namespace CppEditor;
+using namespace LanguageClient;
+using namespace LanguageServerProtocol;
+using namespace TextEditor;
+using namespace Utils;
+
+namespace ClangCodeModel::Internal {
+
+class ClangdSwitchDeclDef::Private
+{
+public:
+    Private(ClangdSwitchDeclDef * q, ClangdClient *client, TextDocument *doc,
+            const QTextCursor &cursor, CppEditorWidget *editorWidget, const LinkHandler &callback)
+        : q(q), client(client), document(doc), uri(DocumentUri::fromFilePath(doc->filePath())),
+          cursor(cursor), editorWidget(editorWidget), callback(callback)
+    {}
+
+    optional<ClangdAstNode> getFunctionNode() const;
+    QTextCursor cursorForFunctionName(const ClangdAstNode &functionNode) const;
+    void handleDeclDefSwitchReplies();
+
+    ClangdSwitchDeclDef * const q;
+    ClangdClient * const client;
+    const QPointer<TextDocument> document;
+    const DocumentUri uri;
+    const QTextCursor cursor;
+    const QPointer<CppEditorWidget> editorWidget;
+    const LinkHandler callback;
+    optional<ClangdAstNode> ast;
+    optional<DocumentSymbolsResult> docSymbols;
+};
+
+ClangdSwitchDeclDef::ClangdSwitchDeclDef(ClangdClient *client, TextDocument *doc,
+        const QTextCursor &cursor, CppEditorWidget *editorWidget, const LinkHandler &callback)
+    : QObject(client), d(new Private(this, client, doc, cursor, editorWidget, callback))
+{
+    // Abort if the user does something else with the document in the meantime.
+    connect(doc, &TextDocument::contentsChanged, this, &ClangdSwitchDeclDef::done,
+            Qt::QueuedConnection);
+    if (editorWidget) {
+        connect(editorWidget, &CppEditorWidget::cursorPositionChanged,
+                this, &ClangdSwitchDeclDef::done, Qt::QueuedConnection);
+    }
+    connect(qApp, &QApplication::focusChanged,
+            this, &ClangdSwitchDeclDef::done, Qt::QueuedConnection);
+
+    connect(client->documentSymbolCache(), &DocumentSymbolCache::gotSymbols, this,
+            [this](const DocumentUri &uri, const DocumentSymbolsResult &symbols) {
+        if (uri != d->uri)
+            return;
+        d->docSymbols = symbols;
+        if (d->ast)
+            d->handleDeclDefSwitchReplies();
+    });
+
+
+    // Retrieve AST and document symbols.
+    const auto astHandler = [this, self = QPointer(this)]
+            (const ClangdAstNode &ast, const MessageId &) {
+        qCDebug(clangdLog) << "received ast for decl/def switch";
+        if (!self)
+            return;
+         if (!d->document) {
+             emit done();
+             return;
+         }
+        if (!ast.isValid()) {
+            emit done();
+            return;
+        }
+        d->ast = ast;
+        if (d->docSymbols)
+            d->handleDeclDefSwitchReplies();
+
+    };
+    client->getAndHandleAst(doc, astHandler, ClangdClient::AstCallbackMode::SyncIfPossible, {});
+    client->documentSymbolCache()->requestSymbols(d->uri, Schedule::Now);
+}
+
+ClangdSwitchDeclDef::~ClangdSwitchDeclDef()
+{
+    delete d;
+}
+
+optional<ClangdAstNode> ClangdSwitchDeclDef::Private::getFunctionNode() const
+{
+    QTC_ASSERT(ast, return {});
+
+    const ClangdAstPath path = getAstPath(*ast, Range(cursor));
+    for (auto it = path.rbegin(); it != path.rend(); ++it) {
+        if (it->role() == "declaration"
+                && (it->kind() == "CXXMethod" || it->kind() == "CXXConversion"
+                    || it->kind() == "CXXConstructor" || it->kind() == "CXXDestructor"
+                    || it->kind() == "Function")) {
+            return *it;
+        }
+    }
+    return {};
+}
+
+QTextCursor ClangdSwitchDeclDef::Private::cursorForFunctionName(const ClangdAstNode &functionNode) const
+{
+    QTC_ASSERT(docSymbols, return {});
+
+    const auto symbolList = Utils::get_if<QList<DocumentSymbol>>(&*docSymbols);
+    if (!symbolList)
+        return {};
+    const Range &astRange = functionNode.range();
+    QList symbolsToCheck = *symbolList;
+    while (!symbolsToCheck.isEmpty()) {
+        const DocumentSymbol symbol = symbolsToCheck.takeFirst();
+        if (symbol.range() == astRange)
+            return symbol.selectionRange().start().toTextCursor(document->document());
+        if (symbol.range().contains(astRange))
+            symbolsToCheck << symbol.children().value_or(QList<DocumentSymbol>());
+    }
+    return {};
+}
+
+void ClangdSwitchDeclDef::Private::handleDeclDefSwitchReplies()
+{
+    if (!document) {
+        emit q->done();
+        return;
+    }
+
+    // Find the function declaration or definition associated with the cursor.
+    // For instance, the cursor could be somwehere inside a function body or
+    // on a function return type, or ...
+    if (clangdLogAst().isDebugEnabled())
+        ast->print(0);
+    const Utils::optional<ClangdAstNode> functionNode = getFunctionNode();
+    if (!functionNode) {
+        emit q->done();
+        return;
+    }
+
+    // Unfortunately, the AST does not contain the location of the actual function name symbol,
+    // so we have to look for it in the document symbols.
+    const QTextCursor funcNameCursor = cursorForFunctionName(*functionNode);
+    if (!funcNameCursor.isNull()) {
+        client->followSymbol(document.data(), funcNameCursor, editorWidget, callback,
+                             true, false);
+    }
+    emit q->done();
+}
+
+} // namespace ClangCodeModel::Internal