mpd/src/io/FileReader.cxx
2021-12-03 14:35:41 +01:00

162 lines
3.6 KiB
C++

/*
* Copyright 2014-2019 Max Kellermann <max.kellermann@gmail.com>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* - Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* FOUNDATION OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
* OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "FileReader.hxx"
#include "fs/FileInfo.hxx"
#include "system/Error.hxx"
#include "io/Open.hxx"
#include <cassert>
#ifdef _WIN32
FileReader::FileReader(Path _path)
:path(_path),
handle(CreateFile(path.c_str(), GENERIC_READ, FILE_SHARE_READ,
nullptr, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL,
nullptr))
{
if (handle == INVALID_HANDLE_VALUE)
throw FormatLastError("Failed to open %s", path.ToUTF8().c_str());
}
FileInfo
FileReader::GetFileInfo() const
{
assert(IsDefined());
return FileInfo(path);
}
size_t
FileReader::Read(void *data, size_t size)
{
assert(IsDefined());
DWORD nbytes;
if (!ReadFile(handle, data, size, &nbytes, nullptr))
throw FormatLastError("Failed to read from %s",
path.ToUTF8().c_str());
return nbytes;
}
void
FileReader::Seek(off_t offset)
{
assert(IsDefined());
auto result = SetFilePointer(handle, offset, nullptr, FILE_BEGIN);
if (result == INVALID_SET_FILE_POINTER)
throw MakeLastError("Failed to seek");
}
void
FileReader::Skip(off_t offset)
{
assert(IsDefined());
auto result = SetFilePointer(handle, offset, nullptr, FILE_CURRENT);
if (result == INVALID_SET_FILE_POINTER)
throw MakeLastError("Failed to seek");
}
void
FileReader::Close() noexcept
{
assert(IsDefined());
CloseHandle(handle);
}
#else
FileReader::FileReader(Path _path)
:path(_path), fd(OpenReadOnly(path.c_str()))
{
}
FileInfo
FileReader::GetFileInfo() const
{
assert(IsDefined());
FileInfo info;
const bool success = fstat(fd.Get(), &info.st) == 0;
if (!success)
throw FormatErrno("Failed to access %s",
path.ToUTF8().c_str());
return info;
}
size_t
FileReader::Read(void *data, size_t size)
{
assert(IsDefined());
ssize_t nbytes = fd.Read(data, size);
if (nbytes < 0)
throw FormatErrno("Failed to read from %s", path.ToUTF8().c_str());
return nbytes;
}
void
FileReader::Seek(off_t offset)
{
assert(IsDefined());
auto result = fd.Seek(offset);
const bool success = result >= 0;
if (!success)
throw MakeErrno("Failed to seek");
}
void
FileReader::Skip(off_t offset)
{
assert(IsDefined());
auto result = fd.Skip(offset);
const bool success = result >= 0;
if (!success)
throw MakeErrno("Failed to seek");
}
void
FileReader::Close() noexcept
{
assert(IsDefined());
fd.Close();
}
#endif