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/*
* libfud
* Copyright 2024 Dominick Allen
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#ifndef FUD_PERMISSIONS_HPP
#define FUD_PERMISSIONS_HPP
#include <climits>
#include <cstdint>
#include <sys/stat.h>
#include <type_traits>
namespace fud {
static_assert(CHAR_BIT == 8, "Assume that uint8_t has 8 bits");
static_assert(sizeof(uint8_t) == 1, "Assume that uint8_t is 1 byte");
enum class PermissionType : uint8_t
{
None = 0x00,
Exec = 0x01,
Write = 0x02,
Read = 0x04
};
struct PermissionField {
explicit constexpr PermissionField(PermissionType permissionType) :
m_permissions{static_cast<uint8_t>(permissionType)}
{
}
constexpr PermissionField(PermissionType lhs, PermissionType rhs)
{
m_permissions = static_cast<uint8_t>(lhs) | static_cast<uint8_t>(rhs);
}
constexpr PermissionField(PermissionType lhs, PermissionField rhs)
{
m_permissions = static_cast<uint8_t>(lhs) | rhs.m_permissions;
}
constexpr PermissionField(PermissionField lhs, PermissionType rhs)
{
m_permissions = lhs.m_permissions | static_cast<uint8_t>(rhs);
}
constexpr PermissionField(PermissionField lhs, PermissionField rhs)
{
m_permissions = lhs.m_permissions | rhs.m_permissions;
}
constexpr uint16_t operator()()
{
return m_permissions;
}
uint8_t m_permissions{};
};
enum class PermissionSpecialType : uint8_t
{
None = 0x00,
Sticky = 0x01,
SetGroupId = 0x02,
SetUserId = 0x04
};
struct PermissionSpecial {
explicit constexpr PermissionSpecial(PermissionSpecialType permissionType) :
m_permissions{static_cast<uint8_t>(permissionType)}
{
}
constexpr PermissionSpecial(PermissionSpecialType lhs, PermissionSpecialType rhs)
{
m_permissions = static_cast<uint8_t>(lhs) | static_cast<uint8_t>(rhs);
}
constexpr PermissionSpecial(PermissionSpecialType lhs, PermissionSpecial rhs)
{
m_permissions = static_cast<uint8_t>(lhs) | rhs.m_permissions;
}
constexpr PermissionSpecial(PermissionSpecial lhs, PermissionSpecialType rhs)
{
m_permissions = lhs.m_permissions | static_cast<uint8_t>(rhs);
}
constexpr PermissionSpecial(PermissionSpecial lhs, PermissionSpecial rhs)
{
m_permissions = lhs.m_permissions | rhs.m_permissions;
}
constexpr uint16_t operator()()
{
return m_permissions;
}
uint8_t m_permissions{0};
};
class Permissions {
public:
static constexpr uint8_t GroupShift = 3;
static constexpr uint8_t UserShift = GroupShift + 3;
static constexpr uint8_t SpecialShift = UserShift + 3;
constexpr Permissions(PermissionField user, PermissionField group, PermissionField others)
{
m_permissions = user() << UserShift | group() << GroupShift | others();
}
template <typename U, typename G, typename O>
constexpr Permissions(U user, G group, O others)
{
m_permissions = PermissionField{user}() << UserShift | PermissionField{group}() << GroupShift |
PermissionField{others}();
}
constexpr Permissions(
PermissionField user,
PermissionField group,
PermissionField others,
PermissionSpecial special)
{
m_permissions = special() << SpecialShift | user() << UserShift | group() << GroupShift | others();
}
template <typename U, typename G, typename O, typename S>
constexpr Permissions(
PermissionField user,
PermissionField group,
PermissionField others,
PermissionSpecial special)
{
m_permissions = special() << SpecialShift | PermissionField{user}() << UserShift |
PermissionField{group}() << GroupShift | PermissionField{others}();
}
constexpr int32_t operator()()
{
return m_permissions;
}
constexpr mode_t mode()
{
return static_cast<mode_t>(m_permissions);
}
private:
int32_t m_permissions{0};
};
constexpr PermissionField operator|(PermissionType lhs, PermissionType rhs)
{
return PermissionField{lhs, rhs};
}
constexpr PermissionField operator|(PermissionType lhs, PermissionField rhs)
{
return PermissionField{lhs, rhs};
}
constexpr PermissionField operator|(PermissionField lhs, PermissionType rhs)
{
return PermissionField{lhs, rhs};
}
constexpr PermissionField operator|(PermissionField lhs, PermissionField rhs)
{
return PermissionField{lhs, rhs};
}
constexpr PermissionField PermReadWrite = PermissionType::Read | PermissionType::Write;
constexpr Permissions PermAllReadWrite{PermReadWrite, PermReadWrite, PermReadWrite};
constexpr Permissions PermUserGroupReadWrite{PermReadWrite, PermReadWrite, PermissionField{PermissionType::None}};
constexpr Permissions PermUserRwGroupRead{PermReadWrite, PermReadWrite, PermissionField{PermissionType::None}};
} // namespace fud
#endif
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