core/debugger: Implement new GDB stub debugger

src/core/debugger/debugger_interface.h

@@ -0,0 +1,74 @@
+// SPDX-FileCopyrightText: Copyright 2022 yuzu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+#include <functional>
+#include <span>
+#include <vector>
+
+#include "common/common_types.h"
+
+namespace Kernel {
+class KThread;
+}
+
+namespace Core {
+
+enum class DebuggerAction {
+    Interrupt,         // Stop emulation as soon as possible.
+    Continue,          // Resume emulation.
+    StepThread,        // Step the currently-active thread.
+    ShutdownEmulation, // Shut down the emulator.
+};
+
+class DebuggerBackend {
+public:
+    /**
+     * Can be invoked from a callback to synchronously wait for more data.
+     * Will return as soon as least one byte is received. Reads up to 4096 bytes.
+     */
+    virtual std::span<const u8> ReadFromClient() = 0;
+
+    /**
+     * Can be invoked from a callback to write data to the client.
+     * Returns immediately after the data is sent.
+     */
+    virtual void WriteToClient(std::span<const u8> data) = 0;
+
+    /**
+     * Gets the currently active thread when the debugger is stopped.
+     */
+    virtual Kernel::KThread* GetActiveThread() = 0;
+
+    /**
+     * Sets the currently active thread when the debugger is stopped.
+     */
+    virtual void SetActiveThread(Kernel::KThread* thread) = 0;
+};
+
+class DebuggerFrontend {
+public:
+    explicit DebuggerFrontend(DebuggerBackend& backend_) : backend{backend_} {}
+
+    /**
+     * Called after the client has successfully connected to the port.
+     */
+    virtual void Connected() = 0;
+
+    /**
+     * Called when emulation has stopped.
+     */
+    virtual void Stopped(Kernel::KThread* thread) = 0;
+
+    /**
+     * Called when new data is asynchronously received on the client socket.
+     * A list of actions to perform is returned.
+     */
+    [[nodiscard]] virtual std::vector<DebuggerAction> ClientData(std::span<const u8> data) = 0;
+
+protected:
+    DebuggerBackend& backend;
+};
+
+} // namespace Core