From b7240037d10dd7c4750bc9fd825dfc30eca5d1e4 Mon Sep 17 00:00:00 2001
From: falsycat <me@falsy.cat>
Date: Tue, 31 May 2022 22:07:41 +0900
Subject: [PATCH] add LuaJIT/Context

---
 CMakeLists.txt         |  1 +
 common/lj_queue.hh     | 25 ++++++++++++
 file/luajit_context.cc | 92 ++++++++++++++++++++++++++++++++++++++++++
 tool/init.cc           |  2 +
 4 files changed, 120 insertions(+)
 create mode 100644 common/lj_queue.hh
 create mode 100644 file/luajit_context.cc

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 0584474..d987ca0 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -68,6 +68,7 @@ target_sources(nf7
     common/wait_queue.hh
     common/yas.hh
 
+    file/luajit_context.cc
     file/node_network.cc
     file/system_dir.cc
     file/system_imgui_config.cc
diff --git a/common/lj_queue.hh b/common/lj_queue.hh
new file mode 100644
index 0000000..256a213
--- /dev/null
+++ b/common/lj_queue.hh
@@ -0,0 +1,25 @@
+#pragma once
+
+#include <memory>
+
+#include <lua.hpp>
+
+#include "nf7.hh"
+
+
+namespace nf7::lj {
+
+class Queue : public File::Interface {
+ public:
+  using Task = std::function<void(lua_State*)>;
+
+  Queue() = default;
+  Queue(const Queue&) = delete;
+  Queue(Queue&&) = delete;
+  Queue& operator=(const Queue&) = delete;
+  Queue& operator=(Queue&&) = delete;
+
+  virtual void Push(const std::shared_ptr<nf7::Context>&, Task&&) noexcept = 0;
+};
+
+}  // namespace nf7::lj
diff --git a/file/luajit_context.cc b/file/luajit_context.cc
new file mode 100644
index 0000000..a14c842
--- /dev/null
+++ b/file/luajit_context.cc
@@ -0,0 +1,92 @@
+#include <atomic>
+#include <functional>
+#include <memory>
+#include <thread>
+
+#include <imgui.h>
+
+#include "nf7.hh"
+
+#include "common/dir_item.hh"
+#include "common/generic_type_info.hh"
+#include "common/lj_queue.hh"
+#include "common/ptr_selector.hh"
+#include "common/wait_queue.hh"
+
+
+namespace nf7 {
+namespace {
+
+class LuaContext final : public nf7::File,
+    public nf7::DirItem,
+    public nf7::lj::Queue {
+ public:
+  static inline const GenericTypeInfo<LuaContext> kType = {"LuaJIT/Context", {"DirItem",}};
+
+  LuaContext(Env& env) noexcept :
+      File(kType, env), DirItem(DirItem::kTooltip),
+      th_([this]() { Main(); }) {
+  }
+  ~LuaContext() noexcept {
+    alive_ = false;
+    q_.Notify();
+    th_.join();
+  }
+
+  LuaContext(Env& env, Deserializer&) noexcept : LuaContext(env) {
+  }
+  void Serialize(Serializer&) const noexcept override {
+  }
+  std::unique_ptr<File> Clone(Env& env) const noexcept override {
+    return std::make_unique<LuaContext>(env);
+  }
+
+  void Push(const std::shared_ptr<nf7::Context>&,
+            std::function<void(lua_State*)>&& f) noexcept override {
+    q_.Push(std::move(f));
+  }
+
+  void UpdateTooltip() noexcept override;
+
+  File::Interface* interface(const std::type_info& t) noexcept override {
+    return nf7::InterfaceSelector<nf7::DirItem, nf7::lj::Queue>(t).Select(this);
+  }
+
+ private:
+  std::atomic<bool> alive_ = true;
+  std::thread       th_;
+
+  std::atomic<size_t> tasks_done_;
+
+  nf7::WaitQueue<std::function<void(lua_State*)>> q_;
+
+  void Main() noexcept {
+    lua_State* L = luaL_newstate();
+    if (!L) {
+      alive_ = false;
+      return;
+    }
+    bool alive = true;
+    while (std::exchange(alive, alive_)) {
+      while (auto task = q_.Pop()) {
+        lua_settop(L, 0);
+        (*task)(L);
+        ++tasks_done_;
+      }
+      if (alive_) q_.Wait();
+    }
+    lua_close(L);
+  }
+};
+
+void LuaContext::UpdateTooltip() noexcept {
+  ImGui::Text("tasks done: %zu", static_cast<size_t>(tasks_done_));
+  if (alive_) {
+    ImGui::TextDisabled("LuaJIT thread is running normally");
+  } else {
+    ImGui::TextUnformatted("LuaJIT thread is **ABORTED**");
+  }
+}
+
+}
+}  // namespace nf7
diff --git a/tool/init.cc b/tool/init.cc
index 6df440f..969b9ac 100644
--- a/tool/init.cc
+++ b/tool/init.cc
@@ -46,6 +46,8 @@ int main(void) {
         Write(ar, "System/ImGuiConfig"s, ""s) },
     { "_logger"s,
         Write(ar, "System/Logger"s, WINDOW_(true), 1024, false, false) },
+    { "_luajit"s,
+        Write(ar, "LuaJIT/Context"s) },
     { "home"s,
         Write(ar, "System/Dir"s, std::map<std::string, L> {}, WINDOW_(false)) },
   }, WINDOW_(true));