fs/io/FileOutputStream: move code to new class BaseFileOutputStream

This commit is contained in:
Max Kellermann 2015-03-23 22:35:43 +01:00
parent 6dc3097998
commit 06827cfcf1
2 changed files with 101 additions and 49 deletions

View File

@ -37,37 +37,33 @@ FileOutputStream::Create(Path path, Error &error)
#ifdef WIN32
FileOutputStream::FileOutputStream(Path _path, Error &error)
:path(_path),
handle(CreateFile(path.c_str(), GENERIC_WRITE, 0, nullptr,
CREATE_ALWAYS,
FILE_ATTRIBUTE_NORMAL|FILE_FLAG_WRITE_THROUGH,
nullptr))
:BaseFileOutputStream(_path)
{
if (handle == INVALID_HANDLE_VALUE) {
const auto path_utf8 = path.ToUTF8();
SetHandle(CreateFile(_path.c_str(), GENERIC_WRITE, 0, nullptr,
CREATE_ALWAYS,
FILE_ATTRIBUTE_NORMAL|FILE_FLAG_WRITE_THROUGH,
nullptr));
if (!IsDefined())
error.FormatLastError("Failed to create %s",
path_utf8.c_str());
}
GetPath().ToUTF8().c_str());
}
bool
FileOutputStream::Write(const void *data, size_t size, Error &error)
BaseFileOutputStream::Write(const void *data, size_t size, Error &error)
{
assert(IsDefined());
DWORD nbytes;
if (!WriteFile(handle, data, size, &nbytes, nullptr)) {
const auto path_utf8 = path.ToUTF8();
error.FormatLastError("Failed to write to %s",
path_utf8.c_str());
path.ToUTF8().c_str());
return false;
}
if (size_t(nbytes) != size) {
const auto path_utf8 = path.ToUTF8();
error.FormatLastError(ERROR_DISK_FULL,
"Failed to write to %s",
path_utf8.c_str());
path.ToUTF8().c_str());
return false;
}
@ -79,8 +75,7 @@ FileOutputStream::Commit(gcc_unused Error &error)
{
assert(IsDefined());
CloseHandle(handle);
handle = INVALID_HANDLE_VALUE;
Close();
return true;
}
@ -89,9 +84,8 @@ FileOutputStream::Cancel()
{
assert(IsDefined());
CloseHandle(handle);
handle = INVALID_HANDLE_VALUE;
RemoveFile(path);
Close();
RemoveFile(GetPath());
}
#else
@ -124,35 +118,36 @@ OpenTempFile(FileDescriptor &fd, Path path)
#endif /* HAVE_LINKAT */
FileOutputStream::FileOutputStream(Path _path, Error &error)
:path(_path)
:BaseFileOutputStream(_path)
{
#ifdef HAVE_LINKAT
/* try Linux's O_TMPFILE first */
is_tmpfile = OpenTempFile(fd, path);
is_tmpfile = OpenTempFile(SetFD(), GetPath());
if (!is_tmpfile) {
#endif
/* fall back to plain POSIX */
if (!fd.Open(path.c_str(),
O_WRONLY|O_CREAT|O_TRUNC,
0666))
error.FormatErrno("Failed to create %s", path.c_str());
if (!SetFD().Open(GetPath().c_str(),
O_WRONLY|O_CREAT|O_TRUNC,
0666))
error.FormatErrno("Failed to create %s",
GetPath().c_str());
#ifdef HAVE_LINKAT
}
#endif
}
bool
FileOutputStream::Write(const void *data, size_t size, Error &error)
BaseFileOutputStream::Write(const void *data, size_t size, Error &error)
{
assert(IsDefined());
ssize_t nbytes = fd.Write(data, size);
if (nbytes < 0) {
error.FormatErrno("Failed to write to %s", path.c_str());
error.FormatErrno("Failed to write to %s", GetPath().c_str());
return false;
} else if ((size_t)nbytes < size) {
error.FormatErrno(ENOSPC,
"Failed to write to %s", path.c_str());
"Failed to write to %s", GetPath().c_str());
return false;
}
@ -166,24 +161,25 @@ FileOutputStream::Commit(Error &error)
#if HAVE_LINKAT
if (is_tmpfile) {
RemoveFile(path);
RemoveFile(GetPath());
/* hard-link the temporary file to the final path */
char fd_path[64];
snprintf(fd_path, sizeof(fd_path), "/proc/self/fd/%d",
fd.Get());
if (linkat(AT_FDCWD, fd_path, AT_FDCWD, path.c_str(),
GetFD().Get());
if (linkat(AT_FDCWD, fd_path, AT_FDCWD, GetPath().c_str(),
AT_SYMLINK_FOLLOW) < 0) {
error.FormatErrno("Failed to commit %s", path.c_str());
fd.Close();
error.FormatErrno("Failed to commit %s",
GetPath().c_str());
Close();
return false;
}
}
#endif
bool success = fd.Close();
bool success = Close();
if (!success)
error.FormatErrno("Failed to commit %s", path.c_str());
error.FormatErrno("Failed to commit %s", GetPath().c_str());
return success;
}
@ -193,12 +189,12 @@ FileOutputStream::Cancel()
{
assert(IsDefined());
fd.Close();
Close();
#ifdef HAVE_LINKAT
if (!is_tmpfile)
#endif
RemoveFile(path);
RemoveFile(GetPath());
}
#endif

View File

@ -37,7 +37,7 @@
class Path;
class FileOutputStream final : public OutputStream {
class BaseFileOutputStream : public OutputStream {
const AllocatedPath path;
#ifdef WIN32
@ -46,6 +46,73 @@ class FileOutputStream final : public OutputStream {
FileDescriptor fd;
#endif
protected:
#ifdef WIN32
template<typename P>
BaseFileOutputStream(P &&_path)
:path(std::forward<P>(_path)),
handle(INVALID_HANDLE_VALUE) {}
#else
template<typename P>
BaseFileOutputStream(P &&_path)
:path(std::forward<P>(_path)),
fd(FileDescriptor::Undefined()) {}
#endif
~BaseFileOutputStream() {
assert(!IsDefined());
}
#ifdef WIN32
void SetHandle(HANDLE _handle) {
assert(!IsDefined());
handle = _handle;
assert(IsDefined());
}
#else
FileDescriptor &SetFD() {
assert(!IsDefined());
return fd;
}
const FileDescriptor &GetFD() const {
return fd;
}
#endif
bool Close() {
assert(IsDefined());
#ifdef WIN32
CloseHandle(handle);
handle = INVALID_HANDLE_VALUE;
return true;
#else
return fd.Close();
#endif
}
public:
bool IsDefined() const {
#ifdef WIN32
return handle != INVALID_HANDLE_VALUE;
#else
return fd.IsDefined();
#endif
}
Path GetPath() const {
return path;
}
/* virtual methods from class OutputStream */
bool Write(const void *data, size_t size, Error &error) override;
};
class FileOutputStream final : public BaseFileOutputStream {
#ifdef HAVE_LINKAT
/**
* Was O_TMPFILE used? If yes, then linkat() must be used to
@ -64,19 +131,8 @@ public:
static FileOutputStream *Create(Path path, Error &error);
bool IsDefined() const {
#ifdef WIN32
return handle != INVALID_HANDLE_VALUE;
#else
return fd.IsDefined();
#endif
}
bool Commit(Error &error);
void Cancel();
/* virtual methods from class OutputStream */
bool Write(const void *data, size_t size, Error &error) override;
};
#endif