LibCore: Add methods to convert DirectoryEntry types to names

We can either convert DirectoryEntry::type to its representative name or
to the POSIX DT_* name.

Userland/Libraries/LibCore/DirectoryEntry.cpp

@@ -9,6 +9,56 @@
 
 namespace Core {
 
+StringView DirectoryEntry::posix_name_from_directory_entry_type(Type type)
+{
+    switch (type) {
+    case Type::BlockDevice:
+        return "DT_BLK"sv;
+    case Type::CharacterDevice:
+        return "DT_CHR"sv;
+    case Type::Directory:
+        return "DT_DIR"sv;
+    case Type::File:
+        return "DT_REG"sv;
+    case Type::NamedPipe:
+        return "DT_FIFO"sv;
+    case Type::Socket:
+        return "DT_SOCK"sv;
+    case Type::SymbolicLink:
+        return "DT_LNK"sv;
+    case Type::Unknown:
+        return "DT_UNKNOWN"sv;
+    case Type::Whiteout:
+        return "DT_WHT"sv;
+    }
+    VERIFY_NOT_REACHED();
+}
+
+StringView DirectoryEntry::representative_name_from_directory_entry_type(Type type)
+{
+    switch (type) {
+    case Type::BlockDevice:
+        return "BlockDevice"sv;
+    case Type::CharacterDevice:
+        return "CharacterDevice"sv;
+    case Type::Directory:
+        return "Directory"sv;
+    case Type::File:
+        return "File"sv;
+    case Type::NamedPipe:
+        return "NamedPipe"sv;
+    case Type::Socket:
+        return "Socket"sv;
+    case Type::SymbolicLink:
+        return "SymbolicLink"sv;
+    case Type::Unknown:
+        return "Unknown"sv;
+    case Type::Whiteout:
+        return "Whiteout"sv;
+    }
+    VERIFY_NOT_REACHED();
+}
+
 DirectoryEntry::Type DirectoryEntry::directory_entry_type_from_stat(mode_t st_mode)
 {
     switch (st_mode & S_IFMT) {

Userland/Libraries/LibCore/DirectoryEntry.h

@@ -7,6 +7,7 @@
 #pragma once
 
 #include <AK/ByteString.h>
+#include <AK/StringView.h>
 #include <dirent.h>
 
 namespace Core {
@@ -28,6 +29,8 @@ struct DirectoryEntry {
     ByteString name;
     ino_t inode_number;
 
+    static StringView posix_name_from_directory_entry_type(Type);
+    static StringView representative_name_from_directory_entry_type(Type);
     static Type directory_entry_type_from_stat(mode_t st_mode);
     static DirectoryEntry from_dirent(dirent const&);
     static DirectoryEntry from_stat(DIR*, dirent const&);