lbrycrd/src/fs.h

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2018-12-29 10:08:32 +01:00
// Copyright (c) 2017-2018 The Bitcoin Core developers
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// Distributed under the MIT software license, see the accompanying
// file COPYING or http://www.opensource.org/licenses/mit-license.php.
#ifndef BITCOIN_FS_H
#define BITCOIN_FS_H
#include <stdio.h>
#include <string>
#if defined WIN32 && defined __GLIBCXX__
#include <ext/stdio_filebuf.h>
#endif
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#include <boost/filesystem.hpp>
#include <boost/filesystem/fstream.hpp>
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/** Filesystem operations and types */
namespace fs = boost::filesystem;
/** Bridge operations to C stdio */
namespace fsbridge {
FILE *fopen(const fs::path& p, const char *mode);
class FileLock
{
public:
FileLock() = delete;
FileLock(const FileLock&) = delete;
FileLock(FileLock&&) = delete;
explicit FileLock(const fs::path& file);
~FileLock();
bool TryLock();
std::string GetReason() { return reason; }
private:
std::string reason;
#ifndef WIN32
int fd = -1;
#else
void* hFile = (void*)-1; // INVALID_HANDLE_VALUE
#endif
};
std::string get_filesystem_error_message(const fs::filesystem_error& e);
// GNU libstdc++ specific workaround for opening UTF-8 paths on Windows.
//
// On Windows, it is only possible to reliably access multibyte file paths through
// `wchar_t` APIs, not `char` APIs. But because the C++ standard doesn't
// require ifstream/ofstream `wchar_t` constructors, and the GNU library doesn't
// provide them (in contrast to the Microsoft C++ library, see
// https://stackoverflow.com/questions/821873/how-to-open-an-stdfstream-ofstream-or-ifstream-with-a-unicode-filename/822032#822032),
// Boost is forced to fall back to `char` constructors which may not work properly.
//
// Work around this issue by creating stream objects with `_wfopen` in
// combination with `__gnu_cxx::stdio_filebuf`. This workaround can be removed
// with an upgrade to C++17, where streams can be constructed directly from
// `std::filesystem::path` objects.
#if defined WIN32 && defined __GLIBCXX__
class ifstream : public std::istream
{
public:
ifstream() = default;
explicit ifstream(const fs::path& p, std::ios_base::openmode mode = std::ios_base::in) { open(p, mode); }
~ifstream() { close(); }
void open(const fs::path& p, std::ios_base::openmode mode = std::ios_base::in);
bool is_open() { return m_filebuf.is_open(); }
void close();
private:
__gnu_cxx::stdio_filebuf<char> m_filebuf;
FILE* m_file = nullptr;
};
class ofstream : public std::ostream
{
public:
ofstream() = default;
explicit ofstream(const fs::path& p, std::ios_base::openmode mode = std::ios_base::out) { open(p, mode); }
~ofstream() { close(); }
void open(const fs::path& p, std::ios_base::openmode mode = std::ios_base::out);
bool is_open() { return m_filebuf.is_open(); }
void close();
private:
__gnu_cxx::stdio_filebuf<char> m_filebuf;
FILE* m_file = nullptr;
};
#else // !(WIN32 && __GLIBCXX__)
typedef fs::ifstream ifstream;
typedef fs::ofstream ofstream;
#endif // WIN32 && __GLIBCXX__
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};
#endif // BITCOIN_FS_H