Initial Vexta Core v0.1.0 release

src/fs.h

@@ -0,0 +1,107 @@
+// Copyright (c) 2017-2019 The Bitcoin Core developers
+// Copyright (c) 2017-2019 The DigiByte Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#ifndef DIGIBYTE_FS_H
+#define DIGIBYTE_FS_H
+
+#include <stdio.h>
+#include <string>
+#if defined WIN32 && defined __GLIBCXX__
+#include <ext/stdio_filebuf.h>
+#endif
+
+#include <boost/filesystem.hpp>
+#include <boost/filesystem/fstream.hpp>
+
+/** Filesystem operations and types */
+namespace fs = boost::filesystem;
+
+/** Bridge operations to C stdio */
+namespace fsbridge {
+    FILE *fopen(const fs::path& p, const char *mode);
+
+    /**
+     * Helper function for joining two paths
+     *
+     * @param[in] base  Base path
+     * @param[in] path  Path to combine with base
+     * @returns path unchanged if it is an absolute path, otherwise returns base joined with path. Returns base unchanged if path is empty.
+     * @pre  Base path must be absolute
+     * @post Returned path will always be absolute
+     */
+    fs::path AbsPathJoin(const fs::path& base, const fs::path& path);
+
+    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__
+};
+
+#endif // DIGIBYTE_FS_H