Merge pull request 'feat/169-lua-imgui' (#176) from feat/169-lua-imgui into main

Reviewed-on: #176

cmake/imgui4lua.cmake

@@ -0,0 +1,23 @@
+function(_imgui4lua_main)
+  set(dir "${CMAKE_CURRENT_BINARY_DIR}/generated")
+  set(py  "${PROJECT_SOURCE_DIR}/cmake/imgui4lua.py")
+  set(src "${imgui_SOURCE_DIR}/imgui.h")
+  set(dst "${dir}/imgui4lua.inc")
+
+  find_program(SH      sh      REQUIRED)
+  find_program(PYTHON3 python3 REQUIRED)
+  find_program(CLANGXX clang++ REQUIRED)
+
+  make_directory("${dir}")
+  add_custom_command(
+    COMMAND  ${SH} -c "${PYTHON3} '${py}' '${src}' > '${dst}'"
+    OUTPUT  "${dst}"
+    DEPENDS "${src}" "${py}"
+    VERBATIM
+  )
+
+  add_library(imgui4lua INTERFACE)
+  target_sources(imgui4lua PUBLIC "${dst}")
+  target_include_directories(imgui4lua INTERFACE ${CMAKE_CURRENT_BINARY_DIR})
+endfunction()
+_imgui4lua_main()

cmake/imgui4lua.py

@@ -0,0 +1,208 @@
+import json
+import subprocess
+import sys
+
+# ---- GENERATOR DEFINITIONS
+def gen_enum(item):
+  name = item.get("name", "")
+  if name not in kEnumWhitelist:
+    return
+
+  short_name = name[5:-1]
+
+  print(f"{{  // {name}")
+  for child in item.get("inner", []):
+    member_name = child["name"]
+    if not member_name.startswith(name): continue
+    member_short_name = member_name[len(name):]
+    print(f"  lua_pushinteger(L, static_cast<lua_Integer>({member_name})); "+
+          f"lua_setfield(L, -2, \"{short_name}_{member_short_name}\");")
+  print(f"}}  // {name}")
+  print()
+
+def gen_func(name, ovlds):
+  ovld_root = (0, {}, None)
+  for ovld in ovlds:
+    ovld_node = ovld_root
+    idx       = 0
+    for arg in ovld.get("inner", []):
+      if "ParmVarDecl" != arg.get("kind"): continue
+      tname = get_type_from_argument(arg)
+      if tname not in kLuaTypeChecker:
+        break
+      ovld_node[1][tname] = (idx, {}, None)
+      ovld_node = ovld_node[1][tname]
+      idx += 1
+    ovld_node[1]["$"] = (idx, {}, ovld)
+
+  def _output(ovld_node, depth=1):
+    indent = "  "*depth
+    if 0 == len(ovld_node[1]):
+      gen_single_func(ovld_node[2], indent=indent)
+    elif 1 == len(ovld_node[1]):
+      _output(*ovld_node[1].values(), depth=depth)
+    else:
+      for tname in ovld_node[1]:
+        checker = kLuaTypeChecker[tname].replace("#", str(ovld_node[0]+1))
+        print(f"{indent}if ({checker}) {{")
+        _output(ovld_node[1][tname], depth=depth+1)
+        print(f"{indent}}}")
+      print(f"{indent}return luaL_error(L, \"unexpected type in param#{ovld_node[0]}\");")
+  print("lua_pushcfunction(L, [](auto L) {")
+  print("  (void) L;")
+  _output(ovld_root)
+  print("});")
+  print(f"lua_setfield(L, -2, \"{name}\");")
+  print()
+
+def gen_single_func(item, indent=""):
+  name   = item["name"]
+  pops   = []
+  params = []
+  pcount = 0
+  for arg in item.get("inner", []):
+    if "ParmVarDecl" != arg.get("kind"): continue
+    pop, param, push = gen_argument(pcount, arg)
+    pcount += 1
+    pops  .extend(pop)
+    params.extend(param)
+    push  .extend(push)
+
+  pushes  = gen_return(item)
+  use_ret = 0 < len(pushes)
+
+  # text output
+  nl = "\n"+indent
+  cm = ", "
+  if 0 < len(pops):
+    print(f"{indent}{nl.join(pops)}")
+  if use_ret:
+    print(f"{indent}const auto r = ImGui::{name}({cm.join(params)});")
+  else:
+    print(f"{indent}ImGui::{name}({cm.join(params)});")
+  if 0 < len(pushes):
+    print(f"{indent}{nl.join(pushes)}")
+  print(f"{indent}return {len(pushes)};")
+
+def gen_return(item):
+  ftype = item["type"]["qualType"]
+  type  = ftype[0:ftype.find("(")-1]
+
+  if "void" == type:
+    return []
+  if "bool" == type:
+    return ["lua_pushboolean(L, r);"]
+  if "float" == type:
+    return ["lua_pushnumber(L, static_cast<lua_Number>(r));"]
+  if "ImVec2" == type:
+    return [
+        "lua_pushnumber(L, static_cast<lua_Number>(r.x));",
+        "lua_pushnumber(L, static_cast<lua_Number>(r.y));",
+    ]
+
+  print(f"unknown return type: {type}", file=sys.stderr)
+  return []
+
+def gen_argument(pc, item):
+  type = item["type"].get("desugaredQualType", item["type"]["qualType"])
+  n    = pc+1
+  pn   = f"p{pc}"
+
+  if type in ["int", "unsigned int"]:
+    return ([f"const int {pn} = static_cast<{type}>(luaL_checkinteger(L, {n}));"], [pn], [])
+
+  if "bool" == type:
+    return ([f"const bool {pn} = lua_toboolean(L, {n});"], [pn], [])
+
+  if "const char *" == type:
+    return ([f"const char* {pn} = luaL_checkstring(L, {n});"], [pn], [])
+
+  if "const ImVec2 &" == type:
+    return ([
+        f"const float {pn}_1 = static_cast<float>(luaL_checknumber(L, {n}));",
+        f"const float {pn}_2 = static_cast<float>(luaL_checknumber(L, {n}));",
+    ], [f"ImVec2 {{{pn}_1, {pn}_2}}"], [])
+
+  if "bool *" == type:
+    return ([f"bool {pn};"], [f"&{pn}"], [f"lua_pushboolean(L, {pn});"])
+
+  print(f"unknown argument type: {type}", file=sys.stderr)
+  return ([], [], [])
+
+
+# ---- GENERATOR UTILITIES
+def get_type_from_argument(item):
+  return item["type"].get("desugaredQualType", item["type"]["qualType"])
+
+
+# ---- WALKER DEFINITIONS
+class Walker:
+  def __init__(self):
+    self._funcs = {}
+    self._enums = {}
+
+  def emit(self):
+    for x in self._enums: gen_enum(self._enums[x])
+    for x in self._funcs: gen_func(x, self._funcs[x])
+
+  def walk(self, item):
+    kind = item.get("kind")
+    name = item.get("name")
+    if "EnumDecl" == kind:
+      if name in kEnumWhitelist:
+        self._enums[name] = item
+    else:
+      w = self.walk
+      if "NamespaceDecl" == kind:
+        w = self._walk_ns
+      for child in item.get("inner", []):
+        w(child)
+
+  def _walk_ns(self, item):
+    kind = item.get("kind")
+    name = item.get("name")
+    if "FunctionDecl" == kind:
+      if name in kFuncWhitelist:
+        if name not in self._funcs:
+          self._funcs[name] = [item]
+        else:
+          self._funcs[name].append(item)
+    else:
+      self.walk(item)
+
+
+# ---- DATA DEFINITIONS
+kFuncWhitelist = [
+  "Begin",
+  "End",
+  "BeginChild",
+  "EndChild",
+  "IsWindowAppearing",
+  "IsWindowCollapsed",
+  "IsWindowFocused",
+  "IsWindowHovered",
+  "GetWindowPos",
+  "GetWindowSize",
+  "GetWindowWidth",
+  "GetWindowHeight",
+  "Text",
+]
+kEnumWhitelist = [
+  "ImGuiWindowFlags_",
+]
+kLuaTypeChecker = {
+  "int": "LUA_TNUMBER == lua_type(L, #)",
+  "const char *": "LUA_TSTRING == lua_type(L, #)",
+  "$": "lua_isnone(L, #)",
+}
+
+
+# ---- ENTRYPOINT
+proc = subprocess.run(["clang++", "-x", "c++", "-std=c++2b", "-Xclang", "-ast-dump=json", "-fsyntax-only", sys.argv[1]], capture_output=True)
+if 0 == proc.returncode:
+  walker = Walker()
+  walker.walk(json.loads(proc.stdout))
+  walker.emit()
+else:
+  print(proc.stderr.decode("utf-8"))
+  exit(1)

core/CMakeLists.txt

@@ -3,6 +3,7 @@ target_link_libraries(nf7_core
   PUBLIC
     git_hash
     imgui
+    imgui4lua
     luajit
     nf7_config
     nf7_iface

core/imgui/luajit_driver.cc

@@ -12,7 +12,15 @@ namespace nf7::core::imgui {
 
 std::shared_ptr<luajit::Value> LuaJITDriver::MakeExtensionObject(
     luajit::TaskContext& lua) {
-  lua_pushnil(*lua);
+  auto L = *lua;
+
+  lua_newuserdata(L, 0);
+  if (luaL_newmetatable(L, "nf7::core::imgui::LuaJITDriver::Extension")) {
+    lua_createtable(L, 0, 0);
+#   include "generated/imgui4lua.inc"
+    lua_setfield(L, -2, "__index");
+  }
+  lua_setmetatable(L, -2);
   return lua.Register();
 }
 

core/imgui/luajit_driver_test.cc

@@ -38,15 +38,17 @@ TEST_F(ImGuiLuaJITDriver, CompileAndInstall) {
 
   auto fu = nf7::core::imgui::LuaJITDriver::CompileAndInstall(
       *subenv,
-      toVector("local ctx = ...\nctx:trace(\"hello world\")"),
+      toVector(
+          "local ctx = ...\nctx:trace(\"hello world\")\n"
+          "local imgui = ctx:recv():lua()\n"
+          "imgui.Begin(\"helloworld\", true, imgui.WindowFlags_NoResize)\n"
+          "imgui.End()"),
       "test chunk");
 
   concurrency->Push(
       nf7::SyncTask {
-        clock->now() + std::chrono::seconds {2},
+        clock->now() + std::chrono::seconds {10},
         [&](auto&) { DropEnv(); },
       });
   ConsumeTasks();
-
-  // TODO FIXME fix leak
 }

core/luajit/context.cc

@@ -1,6 +1,7 @@
 // No copyright
 #include "core/luajit/context.hh"
 
+#include <atomic>
 #include <mutex>
 #include <vector>
 
@@ -39,6 +40,17 @@ void TaskContext::Push(const nf7::Value& v) noexcept {
         return 1;
       });
       lua_setfield(state_, -2, "type");
+
+      lua_pushcfunction(state_, [](auto L) {
+        const nf7::Value& v = CheckUserData<nf7::Value>(L, 1, "nf7::Value");
+        try {
+          v.data<luajit::Value>()->Push(L);
+        } catch (...) {
+          lua_pushnil(L);
+        }
+        return 1;
+      });
+      lua_setfield(state_, -2, "lua");
     }
     lua_setfield(state_, -2, "__index");
 
@@ -84,13 +96,16 @@ class SyncContext final :
   }
 
   void Push(Task&& task) noexcept override {
+    ++refcnt_;
+
     auto self = std::dynamic_pointer_cast<SyncContext>(shared_from_this());
     concurrency_->Push({
       task.after(),
-      [self, task = std::move(task)](auto&) mutable {
+      [this, self, task = std::move(task)](auto&) mutable {
         TaskContext ctx {self, self->state()};
         lua_settop(*ctx, 0);
         task(ctx);
+        if (0 == --refcnt_) { lua_gc(*ctx, LUA_GCCOLLECT, 0); }
       },
       task.location()
     });
@@ -100,7 +115,8 @@ class SyncContext final :
   using Context::shared_from_this;
 
  private:
-  std::shared_ptr<subsys::Concurrency> concurrency_;
+  const std::shared_ptr<subsys::Concurrency> concurrency_;
+  uint64_t refcnt_ {0};
 };
 
 class AsyncContext final :
@@ -114,6 +130,8 @@ class AsyncContext final :
   }
 
   void Push(Task&& task) noexcept override {
+    ++refcnt_;
+
     std::unique_lock<std::mutex> k {mtx_};
     const auto first = tasks_.empty();
     tasks_.push_back(std::move(task));
@@ -142,7 +160,9 @@ class AsyncContext final :
     TaskContext ctx {self, state()};
     for (auto& task : tasks) {
       task(ctx);
+      --refcnt_;
     }
+    if (0 == refcnt_) { lua_gc(*ctx, LUA_GCCOLLECT, 0); }
   }
 
  private:
@@ -150,6 +170,8 @@ class AsyncContext final :
 
   std::mutex mtx_;
   std::vector<Task> tasks_;
+
+  std::atomic<uint64_t> refcnt_ {0};
 };
 }  // namespace
 

core/luajit/value.hh

@@ -9,6 +9,8 @@
 #include <string_view>
 #include <vector>
 
+#include <lua.hpp>
+
 #include "iface/common/future.hh"
 #include "iface/common/leak_detector.hh"
 #include "iface/common/value.hh"
@@ -45,13 +47,17 @@ class Value final : public nf7::Value::Data, public LeakDetector<Value> {
   Value& operator=(const Value&) = delete;
   Value& operator=(Value&&) = delete;
 
+  void Push(lua_State* L) const noexcept {
+    lua_rawgeti(L, LUA_REGISTRYINDEX, index_);
+  }
+
  public:
   const std::shared_ptr<Context>& context() const noexcept { return ctx_; }
   int index() const noexcept { return index_; }
 
  private:
-  std::shared_ptr<Context> ctx_;
+  const std::shared_ptr<Context> ctx_;
-  int index_;
+  const int index_;
 };
 
 }  // namespace nf7::core::luajit

thirdparty/CMakeLists.txt

@@ -19,6 +19,7 @@ FetchContent_Declare(
 )
 FetchContent_Populate(imgui)
 include(imgui.cmake)
+include(../cmake/imgui4lua.cmake)
 
 # ---- luajit (MIT)
 FetchContent_Declare(