LibCore+Everywhere: Return an Error from DirIterator::error()

This also removes DirIterator::error_string(), since the same strerror()
string will be included when you print the Error itself. Except in `ls`
which is still using fprintf() for now.

Userland/Libraries/LibCore/DeprecatedFile.cpp

@@ -583,7 +583,7 @@ ErrorOr<void> DeprecatedFile::remove(StringView path, RecursionMode mode)
     if (S_ISDIR(path_stat.st_mode) && mode == RecursionMode::Allowed) {
         auto di = DirIterator(path, DirIterator::SkipParentAndBaseDir);
         if (di.has_error())
-            return Error::from_errno(di.error());
+            return di.error();
 
         while (di.has_next()) {
             TRY(remove(di.next_full_path(), RecursionMode::Allowed));

Userland/Libraries/LibCore/DirIterator.cpp

@@ -17,7 +17,7 @@ DirIterator::DirIterator(DeprecatedString path, Flags flags)
 {
     m_dir = opendir(m_path.characters());
     if (!m_dir) {
-        m_error = errno;
+        m_error = Error::from_errno(errno);
     }
 }
 
@@ -31,7 +31,7 @@ DirIterator::~DirIterator()
 
 DirIterator::DirIterator(DirIterator&& other)
     : m_dir(other.m_dir)
-    , m_error(other.m_error)
+    , m_error(move(other.m_error))
     , m_next(move(other.m_next))
     , m_path(move(other.m_path))
     , m_flags(other.m_flags)
@@ -48,7 +48,7 @@ bool DirIterator::advance_next()
         errno = 0;
         auto* de = readdir(m_dir);
         if (!de) {
-            m_error = errno;
+            m_error = Error::from_errno(errno);
             m_next.clear();
             return false;
         }

Userland/Libraries/LibCore/DirIterator.h

@@ -28,9 +28,8 @@ public:
     DirIterator(DirIterator&&);
     DirIterator(DirIterator const&) = delete;
 
-    bool has_error() const { return m_error != 0; }
-    int error() const { return m_error; }
-    char const* error_string() const { return strerror(m_error); }
+    bool has_error() const { return m_error.has_value(); }
+    Error error() const { return Error::copy(m_error.value()); }
     bool has_next();
     Optional<DirectoryEntry> next();
     DeprecatedString next_path();
@@ -39,7 +38,7 @@ public:
 
 private:
     DIR* m_dir = nullptr;
-    int m_error = 0;
+    Optional<Error> m_error;
     Optional<DirectoryEntry> m_next;
     DeprecatedString m_path;
     int m_flags;

Userland/Libraries/LibGUI/FileSystemModel.cpp

@@ -99,8 +99,9 @@ void FileSystemModel::Node::traverse_if_needed()
     auto full_path = this->full_path();
     Core::DirIterator di(full_path, m_model.should_show_dotfiles() ? Core::DirIterator::SkipParentAndBaseDir : Core::DirIterator::SkipDots);
     if (di.has_error()) {
-        m_error = di.error();
-        warnln("DirIterator: {}", di.error_string());
+        auto error = di.error();
+        m_error = error.code();
+        warnln("DirIterator: {}", error);
         return;
     }
 

Userland/Libraries/LibGfx/Font/FontDatabase.cpp

@@ -130,7 +130,7 @@ void FontDatabase::load_all_fonts_from_path(DeprecatedString const& root)
         auto current_directory = path_queue.dequeue();
         Core::DirIterator dir_iterator(current_directory, Core::DirIterator::SkipParentAndBaseDir);
         if (dir_iterator.has_error()) {
-            dbgln("FontDatabase::load_all_fonts_from_path: {}", dir_iterator.error_string());
+            dbgln("FontDatabase::load_all_fonts_from_path: {}", dir_iterator.error());
             continue;
         }
         while (dir_iterator.has_next()) {