feat(furvm): add breakpoints

furvm/include/furvm/executor.hpp

@@ -7,7 +7,6 @@
 
 #include <functional>
 #include <stack>
-#include <utility>
 #include <vector>
 
 namespace furvm {
@@ -29,13 +28,13 @@ static inline executor_flags operator~(executor_flags flags) {
     return executor_flags(~static_cast<std::uint32_t>(flags));
 }
 
-using executor_callback = std::function<void(executor&)>;
-
 class executor {
     friend class context;
 private:
     executor(context* context)
       : m_context(context) {}
+public:
+    using new_frame_callback = std::function<void(executor&)>;
 public:
     /**
      * @brief Executor frame.
@@ -180,7 +179,7 @@ private:
     std::stack<frame>   m_frames;
     std::stack<thing<>> m_stack;
 
-    executor_callback m_newFrameCb = nullptr;
+    new_frame_callback m_newFrameCb = nullptr;
 };
 
 } // namespace furvm

furvm/include/furvm/module.hpp

@@ -145,6 +145,11 @@ struct mod_type {
     }
 };
 
+struct breakpoint {
+    std::function<void(executor&, void*)> callback;
+    void*                                 data;
+};
+
 class mod {
     friend class function;
     friend class serializer;
@@ -379,6 +384,15 @@ public:
         if (var >= m_globalVariables.size()) throw std::runtime_error("invalid slot");
         return m_globalVariables[var];
     }
+public:
+    template <typename Fwd, typename = std::enable_if_t<std::is_constructible_v<breakpoint, Fwd>>>
+    void set_breakpoint(bytecode_pos pos, Fwd&& breakpoint) {
+        m_breakpoints[pos] = std::forward<Fwd>(breakpoint);
+    }
+
+    bool has_breakpoint(bytecode_pos pos) const { return m_breakpoints.find(pos) != m_breakpoints.end(); }
+
+    const breakpoint& breakpoint_at(bytecode_pos pos) const { return m_breakpoints.at(pos); }
 public:
     /**
      * @brief Prints the module in a bytecode form to an output stream.
@@ -410,6 +424,8 @@ private:
     std::vector<thing<>> m_globalVariables;
 
     std::unordered_map<std::string, native_function> m_nativeFunctions;
+
+    std::unordered_map<bytecode_pos, breakpoint> m_breakpoints;
 };
 
 } // namespace furvm

furvm/src/executor.cpp

@@ -176,6 +176,13 @@ void executor::step() {
 
     struct frame& frame = m_frames.top();
 
+    if (frame.mod->has_breakpoint(frame.position)) {
+        m_flags        = m_flags | executor_flags::Suspended;
+        const auto& bp = frame.mod->breakpoint_at(frame.position);
+        bp.callback(*this, bp.data);
+        return;
+    }
+
     instruction instr{};
     frame.position += instr.read(frame.mod->bytecode_view().subview(frame.position));
     switch (instr.type) {