Debugger: Add skeleton for a debugger adapter protocol using engine

- Support the launch of an application
- Support continue/pause an application
- Support add breakpoint only after an app is launched
(I.e. preset breakpoints won't work)
- Support stop the debug session
- "Remove one break breakpoint" works but removes all breakpoints

ToDo:
- Polish the transition between stages
- Fix breakpoints handling
- Add support "Step in", "Step out" and "Step Over"

Task-number: QTCREATORBUG-27279
Change-Id: I5c32ce713f5a0f19cc3b9d995cbbadd8adf6a413
Reviewed-by: Artem Sokolovskii <artem.sokolovskii@qt.io>
Reviewed-by: hjk <hjk@qt.io>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>

src/plugins/debugger/dap/dapengine.h

@@ -0,0 +1,97 @@
+// Copyright (C) 2023 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0+ OR GPL-3.0 WITH Qt-GPL-exception-1.0
+
+#pragma once
+
+#include <debugger/debuggerengine.h>
+#include <utils/qtcprocess.h>
+
+#include <QVariant>
+
+namespace Debugger::Internal {
+
+class DebuggerCommand;
+class GdbMi;
+
+/*
+ * A debugger engine for the debugger adapter protocol.
+ */
+
+class DapEngine : public DebuggerEngine
+{
+public:
+    DapEngine();
+
+private:
+    void executeStepIn(bool) override;
+    void executeStepOut() override;
+    void executeStepOver(bool) override;
+
+    void setupEngine() override;
+    void shutdownInferior() override;
+    void shutdownEngine() override;
+
+    bool canHandleToolTip(const DebuggerToolTipContext &) const override;
+
+    void continueInferior() override;
+    void interruptInferior() override;
+
+    void executeRunToLine(const ContextData &data) override;
+    void executeRunToFunction(const QString &functionName) override;
+    void executeJumpToLine(const ContextData &data) override;
+
+    void activateFrame(int index) override;
+    void selectThread(const Thread &thread) override;
+
+    bool acceptsBreakpoint(const BreakpointParameters &bp) const override;
+    void insertBreakpoint(const Breakpoint &bp) override;
+    void updateBreakpoint(const Breakpoint &bp) override;
+    void removeBreakpoint(const Breakpoint &bp) override;
+
+    void assignValueInDebugger(WatchItem *item,
+        const QString &expr, const QVariant &value) override;
+    void executeDebuggerCommand(const QString &command) override;
+
+    void loadSymbols(const Utils::FilePath &moduleName) override;
+    void loadAllSymbols() override;
+    void requestModuleSymbols(const Utils::FilePath &moduleName) override;
+    void reloadModules() override;
+    void reloadRegisters() override {}
+    void reloadSourceFiles() override {}
+    void reloadFullStack() override {}
+
+    bool supportsThreads() const { return true; }
+    void updateItem(const QString &iname) override;
+
+    void runCommand(const DebuggerCommand &cmd) override;
+    void postDirectCommand(const QJsonObject &ob);
+
+    void refreshLocation(const GdbMi &reportedLocation);
+    void refreshStack(const GdbMi &stack);
+    void refreshLocals(const GdbMi &vars);
+    void refreshModules(const GdbMi &modules);
+    void refreshState(const GdbMi &reportedState);
+    void refreshSymbols(const GdbMi &symbols);
+
+    QString errorMessage(QProcess::ProcessError error) const;
+    bool hasCapability(unsigned cap) const override;
+
+    void claimInitialBreakpoints();
+
+    void handleDabStarted();
+    void handleDabLaunch();
+    void handleDabConfigurationDone();
+
+    void handleDapDone();
+    void readDapStandardOutput();
+    void readDapStandardError();
+    void handleOutput(const QJsonDocument &data);
+    void handleResponse(const QString &ba);
+    void updateAll() override;
+    void updateLocals() override;
+
+    QByteArray m_inbuffer;
+    Utils::QtcProcess m_proc;
+};
+
+} // Debugger::Internal