text: /*
   * Copyright (c) 2021, Krisna Pranav
   *
   * SPDX-License-Identifier: BSD-2-Clause
  */
  
  // includes
  #include <base/StringBuilder.h>
  #include <base/StringView.h>
  #include <base/Vector.h>
  #include <kernel/filesystem/Custody.h>
  #include <kernel/filesystem/Inode.h>
  
  namespace Kernel {
  
  KResultOr<NonnullRefPtr<Custody>> Custody::try_create(Custody* parent, StringView name, Inode& inode, int mount_flags)
  {
      auto name_kstring = KString::try_create(name);
      if (!name_kstring)
          return ENOMEM;
      auto custody = adopt_ref_if_nonnull(new (nothrow) Custody(parent, name_kstring.release_nonnull(), inode, mount_flags));
      if (!custody)
          return ENOMEM;
      return custody.release_nonnull();
  }
  
  Custody::Custody(Custody* parent, NonnullOwnPtr<KString> name, Inode& inode, int mount_flags)
      : m_parent(parent)
      , m_name(move(name))
      , m_inode(inode)
      , m_mount_flags(mount_flags)
  {
  }
  
  Custody::~Custody()
  {
  }
  
  OwnPtr<KString> Custody::try_create_absolute_path() const
  {
      if (!parent())
          return KString::try_create("/"sv);
  
      Vector<Custody const*, 32> custody_chain;
      size_t path_length = 0;
      for (auto* custody = this; custody; custody = custody->parent()) {
          custody_chain.append(custody);
          path_length += custody->m_name->length() + 1;
      }
      VERIFY(path_length > 0);
  
      char* buffer;
      auto string = KString::try_create_uninitialized(path_length - 1, buffer);
      if (!string)
          return string;
      size_t string_index = 0;
      for (size_t custody_index = custody_chain.size() - 1; custody_index > 0; --custody_index) {
          buffer[string_index] = '/';
          ++string_index;
          auto& custody_name = *custody_chain[custody_index - 1]->m_name;
          __builtin_memcpy(buffer + string_index, custody_name.characters(), custody_name.length());
          string_index += custody_name.length();
      }
      VERIFY(string->length() == string_index);
      buffer[string_index] = 0;
      return string;
  }
  
  String Custody::absolute_path() const
  {
      if (!parent())
          return "/";
      Vector<Custody const*, 32> custody_chain;
      for (auto* custody = this; custody; custody = custody->parent())
          custody_chain.append(custody);
      StringBuilder builder;
      for (int i = custody_chain.size() - 2; i >= 0; --i) {
          builder.append('/');
          builder.append(custody_chain[i]->name());
      }
      return builder.to_string();
  }
  
  bool Custody::is_readonly() const
  {
      if (m_mount_flags & MS_RDONLY)
          return true;
  
      return m_inode->fs().is_readonly();
  }
  
  }
  