//===-- FileCache.cpp -----------------------------------------------------===//

//

// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.

// See https://llvm.org/LICENSE.txt for license information.

// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception

//

//===----------------------------------------------------------------------===//

#include "lldb/Host/FileCache.h"

#include "lldb/Host/File.h"

#include "lldb/Host/FileSystem.h"

using namespace lldb;

using namespace lldb_private;

FileCache *FileCache::m_instance = nullptr;

FileCache &FileCache::GetInstance() {

  if (m_instance == nullptr)

    m_instance = new FileCache();

  return *m_instance;

}

lldb::user_id_t FileCache::OpenFile(const FileSpec &file_spec,

                                    File::OpenOptions flags, uint32_t mode,

                                    Status &error) {

  if (!file_spec) {

    error.SetErrorString("empty path");

    return UINT64_MAX;

  }

  auto file = FileSystem::Instance().Open(file_spec, flags, mode);

  if (!file) {

    error = file.takeError();

    return UINT64_MAX;

  }

  lldb::user_id_t fd = file.get()->GetDescriptor();

  m_cache[fd] = std::move(file.get());

  return fd;

}

bool FileCache::CloseFile(lldb::user_id_t fd, Status &error) {

  if (fd == UINT64_MAX) {

    error.SetErrorString("invalid file descriptor");

    return false;

  }

  FDToFileMap::iterator pos = m_cache.find(fd);

  if (pos == m_cache.end()) {

    error.SetErrorStringWithFormat("invalid host file descriptor %" PRIu64, fd);

    return false;

  }

  FileUP &file_up = pos->second;

  if (!file_up) {

    error.SetErrorString("invalid host backing file");

    return false;

  }

  error = file_up->Close();

  m_cache.erase(pos);

  return error.Success();

}

uint64_t FileCache::WriteFile(lldb::user_id_t fd, uint64_t offset,

                              const void *src, uint64_t src_len,

                              Status &error) {

  if (fd == UINT64_MAX) {

    error.SetErrorString("invalid file descriptor");

    return UINT64_MAX;

  }

  FDToFileMap::iterator pos = m_cache.find(fd);

  if (pos == m_cache.end()) {

    error.SetErrorStringWithFormat("invalid host file descriptor %" PRIu64, fd);

    return false;

  }

  FileUP &file_up = pos->second;

  if (!file_up) {

    error.SetErrorString("invalid host backing file");

    return UINT64_MAX;

  }

  if (static_cast<uint64_t>(file_up->SeekFromStart(offset, &error)) != offset ||

      error.Fail())

    return UINT64_MAX;

  size_t bytes_written = src_len;

  error = file_up->Write(src, bytes_written);

  if (error.Fail())

    return UINT64_MAX;

  return bytes_written;

}

uint64_t FileCache::ReadFile(lldb::user_id_t fd, uint64_t offset, void *dst,

                             uint64_t dst_len, Status &error) {

  if (fd == UINT64_MAX) {

    error.SetErrorString("invalid file descriptor");

    return UINT64_MAX;

  }

  FDToFileMap::iterator pos = m_cache.find(fd);

  if (pos == m_cache.end()) {

    error.SetErrorStringWithFormat("invalid host file descriptor %" PRIu64, fd);

    return false;

  }

  FileUP &file_up = pos->second;

  if (!file_up) {

    error.SetErrorString("invalid host backing file");

    return UINT64_MAX;

  }

  if (static_cast<uint64_t>(file_up->SeekFromStart(offset, &error)) != offset ||

      error.Fail())

    return UINT64_MAX;

  size_t bytes_read = dst_len;

  error = file_up->Read(dst, bytes_read);

  if (error.Fail())

    return UINT64_MAX;

  return bytes_read;

}