sync_file.h

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#pragma once
 
#include "di/container/path/path.h"
#include "di/function/container/function.h"
#include "di/util/prelude.h"
#include "di/util/scope_exit.h"
#include "dius/config.h"
#include "dius/error.h"
#include "dius/memory_region.h"
#include "dius/tty.h"
 
#include DIUS_PLATFORM_PATH(system_call.h)
 
namespace dius {
#ifdef DIUS_PLATFORM_LINUX
enum class Protection : int {
    None = PROT_NONE,
    Executable = PROT_EXEC,
    Readable = PROT_READ,
    Writeable = PROT_WRITE,
};
 
DI_DEFINE_ENUM_BITWISE_OPERATIONS(Protection)
 
enum class MapFlags : int {
    None = 0,
    Shared = MAP_SHARED,
    Private = MAP_PRIVATE,
    Fixed = MAP_FIXED,
    Anonymous = MAP_ANONYMOUS,
    Stack = MAP_STACK,
#ifdef MAP_POPULATE
    Populate = MAP_POPULATE,
#endif
};
 
DI_DEFINE_ENUM_BITWISE_OPERATIONS(MapFlags)
#endif
 
class SyncFile {
public:
    enum class Owned { Yes, No };
 
    constexpr SyncFile() = default;
 
    constexpr explicit SyncFile(Owned owned, int fd) : m_owned(owned), m_fd(fd) {}
 
    constexpr SyncFile(SyncFile&& other)
        : m_owned(di::exchange(other.m_owned, Owned::No)), m_fd(di::exchange(other.m_fd, -1)) {}
 
    constexpr ~SyncFile() {
        if (m_owned == Owned::No) {
            return;
        }
        (void) this->close();
    }
 
    auto operator=(SyncFile&& other) -> SyncFile& {
        (void) this->close();
        m_owned = di::exchange(other.m_owned, Owned::No);
        m_fd = di::exchange(other.m_fd, -1);
        return *this;
    }
 
    constexpr auto valid() const -> bool { return m_fd != -1; }
    constexpr explicit operator bool() const { return valid(); }
 
    constexpr auto file_descriptor() const -> int { return m_fd; }
    constexpr auto leak_file_descriptor() -> int {
        m_owned = Owned::No;
        return m_fd;
    }
 
    auto close() -> di::Expected<void, di::GenericCode>;
 
    auto read_some(u64 offset, di::Span<di::Byte>) const -> di::Expected<size_t, di::GenericCode>;
    auto read_some(di::Span<di::Byte>) const -> di::Expected<size_t, di::GenericCode>;
    auto write_some(u64 offset, di::Span<di::Byte const>) const -> di::Expected<size_t, di::GenericCode>;
    auto write_some(di::Span<di::Byte const>) const -> di::Expected<size_t, di::GenericCode>;
 
    auto read_exactly(u64 offset, di::Span<di::Byte>) const -> di::Expected<void, di::GenericCode>;
    auto read_exactly(di::Span<di::Byte>) const -> di::Expected<void, di::GenericCode>;
    auto write_exactly(u64 offset, di::Span<di::Byte const>) const -> di::Expected<void, di::GenericCode>;
    auto write_exactly(di::Span<di::Byte const>) const -> di::Expected<void, di::GenericCode>;
 
    auto resize_file(u64 new_size) const -> di::Expected<void, di::GenericCode>;
 
#ifdef DIUS_PLATFORM_LINUX
    auto map(u64 offset, size_t size, Protection protection, MapFlags flags) const
        -> di::Expected<MemoryRegion, di::GenericCode>;
#endif
 
    auto flush() const -> di::Expected<void, di::GenericCode> { return {}; }
 
    auto interactive_device() const -> bool { return true; }
 
    auto set_tty_window_size(tty::WindowSize size) -> di::Expected<void, di::GenericCode>;
    auto get_tty_window_size() -> di::Expected<tty::WindowSize, di::GenericCode>;
    auto get_psuedo_terminal_path() -> di::Expected<di::Path, di::GenericCode>;
 
    using RawModeToken = di::ScopeExit<di::Function<void()>>;
    auto enter_raw_mode() -> di::Expected<RawModeToken, di::GenericCode>;
 
private:
    Owned m_owned { Owned::No };
    int m_fd { -1 };
};
 
enum class OpenMode { Readonly, WriteNew, WriteClobber, ReadWrite, AppendOnly, ReadWriteClobber, AppendReadWrite };
 
auto open_sync(di::PathView path, OpenMode open_mode, u16 create_mode = 0666)
    -> di::Expected<SyncFile, di::GenericCode>;
auto open_psuedo_terminal_controller(OpenMode open_mode, tty::WindowSize size)
    -> di::Expected<SyncFile, di::GenericCode>;
auto open_tempory_file() -> di::Expected<SyncFile, di::GenericCode>;
auto read_to_string(di::PathView path) -> di::Result<di::String>;
 
inline auto stdin = SyncFile { SyncFile::Owned::No, 0 };
inline auto stdout = SyncFile { SyncFile::Owned::No, 1 };
inline auto stderr = SyncFile { SyncFile::Owned::No, 2 };
}