add Env::GetFileOrThrow()

common/file_ref.hh

@@ -28,18 +28,28 @@ class FileRef {
   FileRef& operator=(const FileRef&) = delete;
   FileRef& operator=(FileRef&&) = delete;
 
-  File& operator*() const
+  File& operator*()
   try {
-    return owner_->env().GetFile(id_);
+    return owner_->env().GetFileOrThrow(id_);
   } catch (ExpiredException&) {
     auto& ret = owner_->ResolveOrThrow(path_);
-    const_cast<File::Id&>(id_) = ret.id();
+    id_ = ret.id();
     return ret;
   }
 
+  FileRef& operator=(const File::Path& path) noexcept {
+    return operator=(File::Path{path});
+  }
+  FileRef& operator=(File::Path&& path) noexcept {
+    if (path_ != path) {
+      path_ = std::move(path);
+      id_   = 0;
+    }
+    return *this;
+  }
+
   const File::Path& path() const noexcept { return path_; }
-  File::Path& path() noexcept { id_ = 0; return path_; }
-  File::Id id() const { **this; return id_; }
+  File::Id id() { **this; return id_; }
 
  private:
   File* owner_;
@@ -63,13 +73,15 @@ struct serializer<
     nf7::FileRef> {
  public:
   template <typename Archive>
-  static Archive& save(Archive& ar, const nf7::FileRef& p) {
-    ar(p.path());
+  static Archive& save(Archive& ar, const nf7::FileRef& ref) {
+    ar(ref.path());
     return ar;
   }
   template <typename Archive>
-  static Archive& load(Archive& ar, nf7::FileRef& p) {
-    ar(p.path());
+  static Archive& load(Archive& ar, nf7::FileRef& ref) {
+    nf7::File::Path path;
+    ar(path);
+    ref = path;
     return ar;
   }
 };

common/logger_ref.hh

@@ -20,7 +20,7 @@ class LoggerRef final {
   LoggerRef& operator=(const LoggerRef&) = default;
   LoggerRef& operator=(LoggerRef&&) = default;
 
-  void SetUp(nf7::File& f, std::string_view name = "_logger") {
+  void SetUp(nf7::File& f, std::string_view name = "_logger") noexcept {
     try {
       id_ = f.id();
       logger_ = f.ResolveUpwardOrThrow(name).
@@ -29,7 +29,7 @@ class LoggerRef final {
       id_ = 0;
     }
   }
-  void TearDown() {
+  void TearDown() noexcept {
     id_     = 0;
     logger_ = nullptr;
   }

file/luajit_obj.cc

@@ -306,7 +306,7 @@ void Obj::Update() noexcept {
         if (path != src_.path()) {
           auto ctx  = std::make_shared<nf7::GenericContext>(env(), id());
           auto task = [this, p = std::move(path)]() mutable {
-            src_.path() = std::move(p);
+            src_ = std::move(p);
             Reset();
           };
           ctx->description() = "changing source path";

file/system_logger.cc

@@ -106,7 +106,7 @@ class Logger final : public nf7::File,
 
   std::string GetPathString(File::Id id) const noexcept
   try {
-    return env().GetFile(id).abspath().Stringify();
+    return env().GetFileOrThrow(id).abspath().Stringify();
   } catch (ExpiredException&) {
     return "[EXPIRED]";
   }

main.cc

@@ -89,7 +89,7 @@ class Env final : public nf7::Env {
   void Handle(const File::Event& e) noexcept override
   try {
     // trigger File::Handle()
-    GetFile(e.id).Handle(e);
+    GetFileOrThrow(e.id).Handle(e);
 
     // trigger file watcher
     auto itr = watchers_map_.find(e.id);
@@ -128,12 +128,9 @@ class Env final : public nf7::Env {
   }
 
  protected:
-  File& GetFile(File::Id id) const override {
+  File* GetFile(File::Id id) const noexcept override {
     auto itr = files_.find(id);
-    if (itr == files_.end()) {
-      throw ExpiredException("file ("+std::to_string(id)+") is expired");
-    }
-    return *itr->second;
+    return itr != files_.end()? itr->second: nullptr;
   }
   File::Id AddFile(File& f) noexcept override {
     auto [itr, ok] = files_.emplace(file_next_++, &f);

nf7.cc

@@ -229,6 +229,11 @@ void Env::Pop() noexcept {
   env_stack_.pop_back();
 }
 
+File& Env::GetFileOrThrow(File::Id id) const {
+  if (auto ret = GetFile(id)) return *ret;
+  throw ExpiredException("file ("+std::to_string(id)+") is expired");
+}
+
 Env::Watcher::Watcher(Env& env) noexcept : env_(&env) {
 }
 Env::Watcher::~Watcher() noexcept {

nf7.hh

@@ -253,7 +253,8 @@ class Env {
   Env& operator=(const Env&) = delete;
   Env& operator=(Env&&) = delete;
 
-  virtual File& GetFile(File::Id) const = 0;
+  virtual File* GetFile(File::Id) const noexcept = 0;
+  File& GetFileOrThrow(File::Id) const;
 
   // all Exec*() methods are thread-safe
   using Task = std::function<void()>;