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#include "cru/base/platform/unix/UnixFileStream.h"
#include "cru/base/Exception.h"
#include "cru/base/io/Stream.h"
#include <fcntl.h>
#include <sys/fcntl.h>
#include <unistd.h>
#include <format>
namespace cru::platform::unix {
using namespace cru::io;
namespace {
bool OflagCanSeek([[maybe_unused]] int oflag) {
// Treat every file seekable.
return true;
}
bool OflagCanRead(int oflag) {
// There is a problem: O_RDONLY is 0. So we must test it specially.
// If it is not write-only. Then it can read.
return !(oflag & O_WRONLY);
}
bool OflagCanWrite(int oflag) { return oflag & O_WRONLY || oflag & O_RDWR; }
int MapSeekOrigin(Stream::SeekOrigin origin) {
switch (origin) {
case Stream::SeekOrigin::Begin:
return SEEK_SET;
case Stream::SeekOrigin::Current:
return SEEK_CUR;
case Stream::SeekOrigin::End:
return SEEK_END;
default:
throw Exception(u"Invalid seek origin.");
}
}
} // namespace
UnixFileStream::UnixFileStream(const char *path, int oflag, mode_t mode) {
file_descriptor_ = UnixFileDescriptor(::open(path, oflag, mode));
if (file_descriptor_ == -1) {
throw ErrnoException(std::format(
"Failed to open file {} with oflag {}, mode {}.", path, oflag, mode));
}
SetSupportedOperations(
{OflagCanSeek(oflag), OflagCanRead(oflag), OflagCanWrite(oflag)});
}
UnixFileStream::UnixFileStream(UnixFileDescriptor fd, bool can_seek,
bool can_read, bool can_write)
: Stream(can_seek, can_read, can_write), file_descriptor_(std::move(fd)) {}
UnixFileStream::~UnixFileStream() { DoClose(); }
Index UnixFileStream::DoSeek(Index offset, SeekOrigin origin) {
off_t result = ::lseek(file_descriptor_, offset, MapSeekOrigin(origin));
if (result == -1) {
throw ErrnoException(u"Failed to seek file.");
}
return result;
}
Index UnixFileStream::DoRead(std::byte *buffer, Index offset, Index size) {
auto result = ::read(file_descriptor_, buffer + offset, size);
if (result == -1) {
throw ErrnoException(u"Failed to read file.");
}
return result;
}
Index UnixFileStream::DoWrite(const std::byte *buffer, Index offset,
Index size) {
auto result = ::write(file_descriptor_, buffer + offset, size);
if (result == -1) {
throw ErrnoException(u"Failed to write file.");
}
return result;
}
void UnixFileStream::DoClose() {
CRU_STREAM_BEGIN_CLOSE
if (file_descriptor_) {
file_descriptor_ = {};
}
}
} // namespace cru::platform::unix
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