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// Copyright 2016 Benjamin Barenblat
//
// 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.
#ifndef POSIX_EXTRAS_H_
#define POSIX_EXTRAS_H_
#include <experimental/optional>
#include <string>
#include <dirent.h>
#include <sys/stat.h>
#include <sys/types.h>
namespace scoville {
class File;
// RAII wrapper for Unix directory streams.
class Directory {
public:
explicit Directory(const File&);
virtual ~Directory() noexcept;
long offset() const;
void Seek(long) noexcept;
std::experimental::optional<dirent> ReadOne();
private:
Directory(const Directory&) = delete;
Directory(Directory&&) = delete;
void operator=(const Directory&) = delete;
void operator=(Directory&&) = delete;
DIR* stream_;
};
// RAII wrapper for Unix file descriptors.
class File {
public:
File(const char* path, int flags) : File(path, flags, 0777) {}
File(const char* path, int flags, mode_t mode);
File(const File&);
File(File&& other) = default;
virtual ~File() noexcept;
const std::string& path() const noexcept { return path_; }
// Calls fstat(2) on the file descriptor.
struct stat Stat() const;
// Calls lstat(2) on the path relative to the file descriptor. The path must
// indeed be relative (i.e., it must not start with '/').
struct stat LinkStatAt(const char* path) const;
// Calls openat(2) on the path relative to the file descriptor. The path must
// indeed be relative (i.e., it must not start with '/').
File OpenAt(const char* path, int flags) const;
File OpenAt(const char* path, int flags, mode_t mode) const;
// Removes the file at the path relative to the file descriptor. The path
// must indeed be relative (i.e., it must not start with '/').
void UnlinkAt(const char* path) const;
private:
File() {}
void operator=(const File&) = delete;
void operator=(File&&) = delete;
// Duplicates fd_ and returns the raw new file descriptor.
int Duplicate() const;
std::string path_;
int fd_;
friend Directory::Directory(const File&);
};
} // scoville
#endif // POSIX_EXTRAS_H_
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