ceph/src/seastar/include/seastar/util/file.hh

   1 /*
   2  * This file is open source software, licensed to you under the terms
   3  * of the Apache License, Version 2.0 (the "License").  See the NOTICE file
   4  * distributed with this work for additional information regarding copyright
   5  * ownership.  You may not use this file except in compliance with the License.
   6  *
   7  * You may obtain a copy of the License at
   8  *
   9  *   http://www.apache.org/licenses/LICENSE-2.0
  10  *
  11  * Unless required by applicable law or agreed to in writing,
  12  * software distributed under the License is distributed on an
  13  * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
  14  * KIND, either express or implied.  See the License for the
  15  * specific language governing permissions and limitations
  16  * under the License.
  17  */
  18
  19 /*
  20  * Copyright 2020 ScyllaDB
  21  */
  22
  23 #pragma once
  24
  25 #include <seastar/core/future.hh>
  26 #include <seastar/core/fstream.hh>
  27 #include <seastar/core/sstring.hh>
  28 #include <seastar/util/std-compat.hh>
  29 #include <seastar/util/short_streams.hh>
  30
  31 namespace seastar {
  32
  33 /// Recursively removes a directory and all of its contents.
  34 ///
  35 /// \param path path of the directory to recursively remove
  36 ///
  37 /// \note
  38 /// Unlike `rm -rf` path has to be a directory and may not refer to a regular file.
  39 ///
  40 /// The function flushes the parent directory of the removed path and so guaranteeing that
  41 /// the remove is stable on disk.
  42 ///
  43 /// The function bails out on first error. In that case, some files and/or sub-directories
  44 /// (and their contents) may be left behind at the level in which the error was detected.
  45 ///
  46 future<> recursive_remove_directory(std::filesystem::path path) noexcept;
  47
  48 /// @}
  49
  50 /// \defgroup fileio-util File and Stream Utilities
  51 /// \ingroup fileio-module
  52 ///
  53 /// \brief
  54 /// These utilities are provided to help perform operations on files and I/O streams.
  55
  56 namespace util {
  57
  58 /// \addtogroup fileio-util
  59 /// @{
  60
  61 template <typename Func>
  62 SEASTAR_CONCEPT(requires requires(Func func, input_stream<char>& in) {
  63      { func(in) };
  64 })
  65 auto with_file_input_stream(const std::filesystem::path& path, Func func, file_open_options file_opts = {}, file_input_stream_options input_stream_opts = {}) {
  66     static_assert(std::is_nothrow_move_constructible_v<Func>);
  67     return open_file_dma(path.native(), open_flags::ro, std::move(file_opts)).then(
  68             [func = std::move(func), input_stream_opts = std::move(input_stream_opts)] (file f) mutable {
  69         return do_with(make_file_input_stream(std::move(f), std::move(input_stream_opts)),
  70                 [func = std::move(func)] (input_stream<char>& in) mutable {
  71             return futurize_invoke(std::move(func), in).finally([&in] {
  72                 return in.close();
  73             });
  74         });
  75     });
  76 }
  77
  78 /// Returns all bytes from the file until eof, accessible in chunks.
  79 ///
  80 /// \note use only on short files to avoid running out of memory.
  81 ///
  82 /// \param path path of the file to be read.
  83 future<std::vector<temporary_buffer<char>>> read_entire_file(std::filesystem::path path);
  84
  85 /// Returns all bytes from the file until eof as a single buffer.
  86 ///
  87 /// \note use only on short files to avoid running out of memory.
  88 ///
  89 /// \param path path of the file to be read.
  90 future<sstring> read_entire_file_contiguous(std::filesystem::path path);
  91
  92 /// @}
  93
  94 } // namespace util
  95
  96 } // namespace seastar