1 files changed, 138 insertions, 0 deletions
diff --git a/src/util/fs.cpp b/src/util/fs.cpp
new file mode 100644
index 0000000000..e8fb72670f
--- /dev/null
+++ b/src/util/fs.cpp
@@ -0,0 +1,138 @@
+// Copyright (c) 2017-2022 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#include <util/fs.h>
+#include <util/syserror.h>
+
+#ifndef WIN32
+#include <cstring>
+#include <fcntl.h>
+#include <sys/file.h>
+#include <sys/utsname.h>
+#include <unistd.h>
+#else
+#include <codecvt>
+#include <limits>
+#include <windows.h>
+#endif
+
+#include <cassert>
+#include <string>
+
+namespace fsbridge {
+
+FILE *fopen(const fs::path& p, const char *mode)
+{
+#ifndef WIN32
+    return ::fopen(p.c_str(), mode);
+#else
+    std::wstring_convert<std::codecvt_utf8_utf16<wchar_t>,wchar_t> utf8_cvt;
+    return ::_wfopen(p.wstring().c_str(), utf8_cvt.from_bytes(mode).c_str());
+#endif
+}
+
+fs::path AbsPathJoin(const fs::path& base, const fs::path& path)
+{
+    assert(base.is_absolute());
+    return path.empty() ? base : fs::path(base / path);
+}
+
+#ifndef WIN32
+
+static std::string GetErrorReason()
+{
+    return SysErrorString(errno);
+}
+
+FileLock::FileLock(const fs::path& file)
+{
+    fd = open(file.c_str(), O_RDWR);
+    if (fd == -1) {
+        reason = GetErrorReason();
+    }
+}
+
+FileLock::~FileLock()
+{
+    if (fd != -1) {
+        close(fd);
+    }
+}
+
+bool FileLock::TryLock()
+{
+    if (fd == -1) {
+        return false;
+    }
+
+    struct flock lock;
+    lock.l_type = F_WRLCK;
+    lock.l_whence = SEEK_SET;
+    lock.l_start = 0;
+    lock.l_len = 0;
+    if (fcntl(fd, F_SETLK, &lock) == -1) {
+        reason = GetErrorReason();
+        return false;
+    }
+
+    return true;
+}
+#else
+
+static std::string GetErrorReason() {
+    wchar_t* err;
+    FormatMessageW(FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS,
+        nullptr, GetLastError(), MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), reinterpret_cast<WCHAR*>(&err), 0, nullptr);
+    std::wstring err_str(err);
+    LocalFree(err);
+    return std::wstring_convert<std::codecvt_utf8_utf16<wchar_t>>().to_bytes(err_str);
+}
+
+FileLock::FileLock(const fs::path& file)
+{
+    hFile = CreateFileW(file.wstring().c_str(),  GENERIC_READ | GENERIC_WRITE, FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE,
+        nullptr, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, nullptr);
+    if (hFile == INVALID_HANDLE_VALUE) {
+        reason = GetErrorReason();
+    }
+}
+
+FileLock::~FileLock()
+{
+    if (hFile != INVALID_HANDLE_VALUE) {
+        CloseHandle(hFile);
+    }
+}
+
+bool FileLock::TryLock()
+{
+    if (hFile == INVALID_HANDLE_VALUE) {
+        return false;
+    }
+    _OVERLAPPED overlapped = {};
+    if (!LockFileEx(hFile, LOCKFILE_EXCLUSIVE_LOCK | LOCKFILE_FAIL_IMMEDIATELY, 0, std::numeric_limits<DWORD>::max(), std::numeric_limits<DWORD>::max(), &overlapped)) {
+        reason = GetErrorReason();
+        return false;
+    }
+    return true;
+}
+#endif
+
+std::string get_filesystem_error_message(const fs::filesystem_error& e)
+{
+#ifndef WIN32
+    return e.what();
+#else
+    // Convert from Multi Byte to utf-16
+    std::string mb_string(e.what());
+    int size = MultiByteToWideChar(CP_ACP, 0, mb_string.data(), mb_string.size(), nullptr, 0);
+
+    std::wstring utf16_string(size, L'\0');
+    MultiByteToWideChar(CP_ACP, 0, mb_string.data(), mb_string.size(), &*utf16_string.begin(), size);
+    // Convert from utf-16 to utf-8
+    return std::wstring_convert<std::codecvt_utf8_utf16<wchar_t>, wchar_t>().to_bytes(utf16_string);
+#endif
+}
+
+} // fsbridge