// Copyright 2014 The Crashpad Authors. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#include "util/file/file_io.h"

#include "base/files/file_path.h"
#include "base/logging.h"
#include "base/numerics/safe_conversions.h"

namespace {

bool IsSocketHandle(HANDLE file) {
  if (GetFileType(file) == FILE_TYPE_PIPE) {
    // FILE_TYPE_PIPE means that it's a socket, a named pipe, or an anonymous
    // pipe. If we are unable to retrieve the pipe information, we know it's a
    // socket.
    return !GetNamedPipeInfo(file, NULL, NULL, NULL, NULL);
  }
  return false;
}

}  // namespace

namespace crashpad {

// TODO(scottmg): Handle > DWORD sized writes if necessary.

ssize_t ReadFile(FileHandle file, void* buffer, size_t size) {
  DCHECK(!IsSocketHandle(file));
  DWORD size_dword = base::checked_cast<DWORD>(size);
  DWORD total_read = 0;
  char* buffer_c = reinterpret_cast<char*>(buffer);
  while (size_dword > 0) {
    DWORD bytes_read;
    BOOL success = ::ReadFile(file, buffer_c, size_dword, &bytes_read, nullptr);
    if (!success && GetLastError() != ERROR_MORE_DATA) {
      return -1;
    } else if (success && bytes_read == 0 &&
               GetFileType(file) != FILE_TYPE_PIPE) {
      // Zero bytes read for a file indicates reaching EOF. Zero bytes read from
      // a pipe indicates only that there was a zero byte WriteFile issued on
      // the other end, so continue reading.
      break;
    }

    buffer_c += bytes_read;
    size_dword -= bytes_read;
    total_read += bytes_read;
  }
  return total_read;
}

ssize_t WriteFile(FileHandle file, const void* buffer, size_t size) {
  // TODO(scottmg): This might need to handle the limit for pipes across a
  // network in the future.
  DWORD size_dword = base::checked_cast<DWORD>(size);
  DWORD bytes_written;
  BOOL rv = ::WriteFile(file, buffer, size_dword, &bytes_written, nullptr);
  if (!rv)
    return -1;
  CHECK_EQ(bytes_written, size_dword);
  return bytes_written;
}

FileHandle LoggingOpenFileForRead(const base::FilePath& path) {
  HANDLE file = CreateFile(path.value().c_str(), GENERIC_READ, FILE_SHARE_READ,
                           nullptr, OPEN_EXISTING, 0, nullptr);
  PLOG_IF(ERROR, file == INVALID_HANDLE_VALUE) << "CreateFile "
                                               << path.value().c_str();
  return file;
}

FileHandle LoggingOpenFileForWrite(const base::FilePath& path,
                                   FileWriteMode mode,
                                   bool world_readable) {
  DWORD disposition = 0;
  switch (mode) {
    case FileWriteMode::kReuseOrCreate:
      disposition = OPEN_ALWAYS;
      break;
    case FileWriteMode::kTruncateOrCreate:
      disposition = CREATE_ALWAYS;
      break;
    case FileWriteMode::kCreateOrFail:
      disposition = CREATE_NEW;
      break;
  }
  HANDLE file = CreateFile(path.value().c_str(), GENERIC_WRITE, 0, nullptr,
                           disposition, FILE_ATTRIBUTE_NORMAL, nullptr);
  PLOG_IF(ERROR, file == INVALID_HANDLE_VALUE) << "CreateFile "
                                               << path.value().c_str();
  return file;
}

FileOffset LoggingSeekFile(FileHandle file, FileOffset offset, int whence) {
  DWORD method = 0;
  switch (whence) {
    case SEEK_SET:
      method = FILE_BEGIN;
      break;
    case SEEK_CUR:
      method = FILE_CURRENT;
      break;
    case SEEK_END:
      method = FILE_END;
      break;
    default:
      NOTREACHED();
      break;
  }

  LARGE_INTEGER distance_to_move;
  distance_to_move.QuadPart = offset;
  LARGE_INTEGER new_offset;
  BOOL result = SetFilePointerEx(file, distance_to_move, &new_offset, method);
  if (!result) {
    PLOG(ERROR) << "SetFilePointerEx";
    return -1;
  }
  return new_offset.QuadPart;
}

bool LoggingCloseFile(FileHandle file) {
  BOOL rv = CloseHandle(file);
  PLOG_IF(ERROR, !rv) << "CloseHandle";
  return rv;
}

}  // namespace crashpad