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LibArchive: Refactor Tar to make DRY (Don't Repeat Yourself)

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Problem:
- The getters and setters duplicate code for conversions.
- Getters are returning `const StringView` rather than non-`const`.

Solution:
- Factor out common code to helper functions.
- Return `StringView` as non-`const`.
This commit is contained in:
Lenny Maiorani 2022-02-15 10:10:35 -07:00 • committed by Idan Horowitz
parent 0ec688f86e
commit 583e197897
2 changed files with 72 additions and 50 deletions
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118
Userland/Libraries/LibArchive/Tar.h
View file

@ -1,6 +1,7 @@
/* /*
* Copyright (c) 2020, Peter Elliott <pelliott@serenityos.org> * Copyright (c) 2020, Peter Elliott <pelliott@serenityos.org>
* Copyright (c) 2021, Idan Horowitz <idan.horowitz@serenityos.org> * Copyright (c) 2021, Idan Horowitz <idan.horowitz@serenityos.org>
* Copyright (c) 2022, the SerenityOS developers.
* *
* SPDX-License-Identifier: BSD-2-Clause * SPDX-License-Identifier: BSD-2-Clause
*/ */
@ -36,42 +37,81 @@ constexpr const char* ustar_version = "00"; // ustar format version
constexpr const char* posix1_tar_magic = ""; // POSIX.1-1988 format magic constexpr const char* posix1_tar_magic = ""; // POSIX.1-1988 format magic
constexpr const char* posix1_tar_version = ""; // POSIX.1-1988 format version constexpr const char* posix1_tar_version = ""; // POSIX.1-1988 format version
template<size_t N>
static size_t get_field_as_integral(const char (&field)[N])
{
size_t value = 0;
for (size_t i = 0; i < N; ++i) {
if (field[i] == 0)
break;
VERIFY(field[i] >= '0' && field[i] <= '7');
value *= 8;
value += field[i] - '0';
}
return value;
}
template<size_t N>
static StringView get_field_as_string_view(const char (&field)[N])
{
return { field, min(__builtin_strlen(field), N) };
}
template<size_t N, class TSource>
static void set_field(char (&field)[N], TSource&& source)
{
if constexpr (requires { source.copy_characters_to_buffer(field, N); }) {
VERIFY(source.copy_characters_to_buffer(field, N));
} else {
memcpy(field, source.characters_without_null_termination(), min(N, source.length()));
}
}
template<class TSource, size_t N>
static void set_octal_field(char (&field)[N], TSource&& source)
{
set_field(field, String::formatted("{:o}", forward<TSource>(source)));
}
class [[gnu::packed]] TarFileHeader { class [[gnu::packed]] TarFileHeader {
public: public:
const StringView filename() const { return StringView(m_filename, min(__builtin_strlen(m_filename), sizeof(m_filename))); } StringView filename() const { return get_field_as_string_view(m_filename); }
mode_t mode() const { return get_tar_field(m_mode); } mode_t mode() const { return get_field_as_integral(m_mode); }
uid_t uid() const { return get_tar_field(m_uid); } uid_t uid() const { return get_field_as_integral(m_uid); }
gid_t gid() const { return get_tar_field(m_gid); } gid_t gid() const { return get_field_as_integral(m_gid); }
// FIXME: support 2001-star size encoding // FIXME: support 2001-star size encoding
size_t size() const { return get_tar_field(m_size); } size_t size() const { return get_field_as_integral(m_size); }
time_t timestamp() const { return get_tar_field(m_timestamp); } time_t timestamp() const { return get_field_as_integral(m_timestamp); }
unsigned checksum() const { return get_tar_field(m_checksum); } unsigned checksum() const { return get_field_as_integral(m_checksum); }
TarFileType type_flag() const { return TarFileType(m_type_flag); } TarFileType type_flag() const { return TarFileType(m_type_flag); }
const StringView link_name() const { return m_link_name; } StringView link_name() const { return m_link_name; }
const StringView magic() const { return StringView(m_magic, min(__builtin_strlen(m_magic), sizeof(m_magic))); } StringView magic() const { return get_field_as_string_view(m_magic); }
const StringView version() const { return StringView(m_version, min(__builtin_strlen(m_version), sizeof(m_version))); } StringView version() const { return get_field_as_string_view(m_version); }
const StringView owner_name() const { return StringView(m_owner_name, min(__builtin_strlen(m_owner_name), sizeof(m_owner_name))); } StringView owner_name() const { return get_field_as_string_view(m_owner_name); }
const StringView group_name() const { return StringView(m_group_name, min(__builtin_strlen(m_group_name), sizeof(m_group_name))); } StringView group_name() const { return get_field_as_string_view(m_group_name); }
int major() const { return get_tar_field(m_major); } int major() const { return get_field_as_integral(m_major); }
int minor() const { return get_tar_field(m_minor); } int minor() const { return get_field_as_integral(m_minor); }
// FIXME: support ustar filename prefix // FIXME: support ustar filename prefix
const StringView prefix() const { return StringView(m_prefix, min(__builtin_strlen(m_prefix), sizeof(m_prefix))); } StringView prefix() const { return get_field_as_string_view(m_prefix); }
void set_filename(const String& filename) { VERIFY(filename.copy_characters_to_buffer(m_filename, sizeof(m_filename))); } void set_filename(const String& filename) { set_field(m_filename, filename); }
void set_mode(mode_t mode) { VERIFY(String::formatted("{:o}", mode).copy_characters_to_buffer(m_mode, sizeof(m_mode))); } void set_mode(mode_t mode) { set_octal_field(m_mode, mode); }
void set_uid(uid_t uid) { VERIFY(String::formatted("{:o}", uid).copy_characters_to_buffer(m_uid, sizeof(m_uid))); } void set_uid(uid_t uid) { set_octal_field(m_uid, uid); }
void set_gid(gid_t gid) { VERIFY(String::formatted("{:o}", gid).copy_characters_to_buffer(m_gid, sizeof(m_gid))); } void set_gid(gid_t gid) { set_octal_field(m_gid, gid); }
void set_size(size_t size) { VERIFY(String::formatted("{:o}", size).copy_characters_to_buffer(m_size, sizeof(m_size))); } void set_size(size_t size) { set_octal_field(m_size, size); }
void set_timestamp(time_t timestamp) { VERIFY(String::formatted("{:o}", timestamp).copy_characters_to_buffer(m_timestamp, sizeof(m_timestamp))); } void set_timestamp(time_t timestamp) { set_octal_field(m_timestamp, timestamp); }
void set_type_flag(TarFileType type) { m_type_flag = static_cast<char>(type); } void set_type_flag(TarFileType type) { m_type_flag = to_underlying(type); }
void set_link_name(const String& link_name) { VERIFY(link_name.copy_characters_to_buffer(m_link_name, sizeof(m_link_name))); } void set_link_name(const String& link_name) { set_field(m_link_name, link_name); }
void set_magic(const char* magic) { memcpy(m_magic, magic, sizeof(m_magic)); } // magic doesn't necessarily include a null byte // magic doesn't necessarily include a null byte
void set_version(const char* version) { memcpy(m_version, version, sizeof(m_version)); } // version doesn't necessarily include a null byte void set_magic(StringView magic) { set_field(m_magic, magic); }
void set_owner_name(const String& owner_name) { VERIFY(owner_name.copy_characters_to_buffer(m_owner_name, sizeof(m_owner_name))); } // version doesn't necessarily include a null byte
void set_group_name(const String& group_name) { VERIFY(group_name.copy_characters_to_buffer(m_group_name, sizeof(m_group_name))); } void set_version(StringView version) { set_field(m_version, version); }
void set_major(int major) { VERIFY(String::formatted("{:o}", major).copy_characters_to_buffer(m_major, sizeof(m_major))); } void set_owner_name(const String& owner_name) { set_field(m_owner_name, owner_name); }
void set_minor(int minor) { VERIFY(String::formatted("{:o}", minor).copy_characters_to_buffer(m_minor, sizeof(m_minor))); } void set_group_name(const String& group_name) { set_field(m_group_name, group_name); }
void set_prefix(const String& prefix) { VERIFY(prefix.copy_characters_to_buffer(m_prefix, sizeof(m_prefix))); } void set_major(int major) { set_octal_field(m_major, major); }
void set_minor(int minor) { set_octal_field(m_minor, minor); }
void set_prefix(const String& prefix) { set_field(m_prefix, prefix); }
unsigned expected_checksum() const; unsigned expected_checksum() const;
void calculate_checksum(); void calculate_checksum();
@ -93,24 +133,6 @@ private:
char m_major[8]; char m_major[8];
char m_minor[8]; char m_minor[8];
char m_prefix[155]; // zero out the prefix for archiving char m_prefix[155]; // zero out the prefix for archiving
template<size_t N>
static size_t get_tar_field(const char (&field)[N]);
}; };
template<size_t N>
size_t TarFileHeader::get_tar_field(const char (&field)[N])
{
size_t value = 0;
for (size_t i = 0; i < N; ++i) {
if (field[i] == 0)
break;
VERIFY(field[i] >= '0' && field[i] <= '7');
value *= 8;
value += field[i] - '0';
}
return value;
}
} }

4
Userland/Libraries/LibArchive/TarStream.cpp
View file

@ -103,8 +103,8 @@ void TarInputStream::advance()
bool TarInputStream::valid() const bool TarInputStream::valid() const
{ {
auto& header_magic = header().magic(); auto const header_magic = header().magic();
auto& header_version = header().version(); auto const header_version = header().version();
if (!((header_magic == gnu_magic && header_version == gnu_version) if (!((header_magic == gnu_magic && header_version == gnu_version)
|| (header_magic == ustar_magic && header_version == ustar_version) || (header_magic == ustar_magic && header_version == ustar_version)