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LibTar: Implement TarOutputStream

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This output stream creates gnu format tar archives
and currently only supports files and directories.
This commit is contained in:
Idan Horowitz 2021-03-13 01:40:04 +02:00 • committed by Andreas Kling
parent 6c1322bdc7
commit 7eab20bad0
4 changed files with 116 additions and 16 deletions
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65
Userland/Libraries/LibTar/TarStream.cpp
View file

@ -26,9 +26,10 @@
*/
#include <LibTar/TarStream.h>
#include <string.h>
namespace Tar {
TarFileStream::TarFileStream(TarStream& tar_stream)
TarFileStream::TarFileStream(TarInputStream& tar_stream)
: m_tar_stream(tar_stream)
, m_generation(tar_stream.m_generation)
{
@ -83,11 +84,12 @@ bool TarFileStream::discard_or_error(size_t count)
return m_tar_stream.m_stream.discard_or_error(count);
}
TarStream::TarStream(InputStream& stream)
TarInputStream::TarInputStream(InputStream& stream)
: m_stream(stream)
{
if (!m_stream.read_or_error(Bytes(&m_header, sizeof(m_header)))) {
m_finished = true;
m_stream.handle_any_error(); // clear out errors so we dont assert
return;
}
VERIFY(m_stream.discard_or_error(block_size - sizeof(Header)));
@ -98,7 +100,7 @@ static constexpr unsigned long block_ceiling(unsigned long offset)
return block_size * (1 + ((offset - 1) / block_size));
}
void TarStream::advance()
void TarInputStream::advance()
{
if (m_finished)
return;
@ -119,17 +121,70 @@ void TarStream::advance()
VERIFY(m_stream.discard_or_error(block_size - sizeof(Header)));
}
bool TarStream::valid() const
bool TarInputStream::valid() const
{
auto& header_magic = header().magic();
auto& header_version = header().version();
return (header_magic == gnu_magic && header_version == gnu_version) || (header_magic == ustar_magic && header_version == ustar_version);
}
TarFileStream TarStream::file_contents()
TarFileStream TarInputStream::file_contents()
{
VERIFY(!m_finished);
return TarFileStream(*this);
}
TarOutputStream::TarOutputStream(OutputStream& stream)
: m_stream(stream)
{
}
void TarOutputStream::add_directory(const String& path, mode_t mode)
{
VERIFY(!m_finished);
Header header;
memset(&header, 0, sizeof(header));
header.set_size(0);
header.set_file_name(String::formatted("{}/", path)); // Old tar implementations assume directory names end with a /
header.set_type_flag(Directory);
header.set_mode(mode);
header.set_magic(gnu_magic);
header.set_version(gnu_version);
header.calculate_checksum();
VERIFY(m_stream.write_or_error(Bytes { &header, sizeof(header) }));
u8 padding[block_size] = { 0 };
VERIFY(m_stream.write_or_error(Bytes { &padding, block_size - sizeof(header) }));
}
void TarOutputStream::add_file(const String& path, mode_t mode, const ReadonlyBytes& bytes)
{
VERIFY(!m_finished);
Header header;
memset(&header, 0, sizeof(header));
header.set_size(bytes.size());
header.set_file_name(path);
header.set_type_flag(NormalFile);
header.set_mode(mode);
header.set_magic(gnu_magic);
header.set_version(gnu_version);
header.calculate_checksum();
VERIFY(m_stream.write_or_error(Bytes { &header, sizeof(header) }));
u8 padding[block_size] = { 0 };
VERIFY(m_stream.write_or_error(Bytes { &padding, block_size - sizeof(header) }));
size_t n_written = 0;
while (n_written < bytes.size()) {
n_written += m_stream.write(bytes.slice(n_written, min(bytes.size() - n_written, block_size)));
}
VERIFY(m_stream.write_or_error(Bytes { &padding, block_size - (n_written % block_size) }));
}
void TarOutputStream::finish()
{
VERIFY(!m_finished);
u8 padding[block_size] = { 0 };
m_stream.write_or_error(Bytes { &padding, block_size }); // 2 empty records that are used to signify the end of the archive
m_stream.write_or_error(Bytes { &padding, block_size });
m_finished = true;
}
}