transmission/libtransmission/variant.h

359 lines
10 KiB
C++

// This file Copyright © 2008-2023 Mnemosyne LLC.
// It may be used under GPLv2 (SPDX: GPL-2.0-only), GPLv3 (SPDX: GPL-3.0-only),
// or any future license endorsed by Mnemosyne LLC.
// License text can be found in the licenses/ folder.
#pragma once
#include <algorithm>
#include <cstddef> // size_t
#include <cstdint> // int64_t
#include <optional>
#include <string>
#include <string_view>
#include "libtransmission/quark.h"
struct tr_error;
/**
* @addtogroup tr_variant Variant
*
* An object that acts like a union for
* integers, strings, lists, dictionaries, booleans, and floating-point numbers.
* The structure is named `tr_variant` due to the historical reason that it was
* originally tightly coupled with bencoded data. It currently supports
* being parsed from, and serialized to, both bencoded notation and json notation.
*
* @{
*/
/* these are PRIVATE IMPLEMENTATION details that should not be touched.
* I'll probably change them just to break your code! HA HA HA!
* it's included in the header for inlining and composition */
enum
{
TR_VARIANT_TYPE_INT = 1,
TR_VARIANT_TYPE_STR = 2,
TR_VARIANT_TYPE_LIST = 4,
TR_VARIANT_TYPE_DICT = 8,
TR_VARIANT_TYPE_BOOL = 16,
TR_VARIANT_TYPE_REAL = 32
};
/* These are PRIVATE IMPLEMENTATION details that should not be touched.
* I'll probably change them just to break your code! HA HA HA!
* it's included in the header for inlining and composition */
struct tr_variant
{
private:
struct String
{
void set_shallow(std::string_view newval)
{
clear();
type_ = Type::View;
str_.str = std::data(newval);
len_ = std::size(newval);
}
void set(std::string_view newval)
{
clear();
len_ = std::size(newval);
if (len_ < sizeof(str_.buf))
{
type_ = Type::Buf;
std::copy_n(std::data(newval), len_, str_.buf);
str_.buf[len_] = '\0';
}
else
{
char* const newstr = new char[len_ + 1];
std::copy_n(std::data(newval), len_, newstr);
newstr[len_] = '\0';
type_ = Type::Heap;
str_.str = newstr;
}
}
[[nodiscard]] constexpr std::string_view get() const noexcept
{
return { type_ == Type::Buf ? str_.buf : str_.str, len_ };
}
void clear()
{
if (type_ == Type::Heap)
{
delete[] str_.str;
}
*this = {};
}
private:
enum class Type
{
Heap,
Buf,
View
};
Type type_ = Type::View;
size_t len_ = 0U;
union
{
char buf[16];
char const* str;
} str_ = {};
};
public:
char type = '\0';
tr_quark key = TR_KEY_NONE;
union
{
bool b;
double d;
int64_t i;
String s;
struct
{
size_t alloc;
size_t count;
struct tr_variant* vals;
} l;
} val = {};
};
/**
* @brief Clear the variant to an empty state.
*
* `tr_variantIsEmpty()` will return true after this is called.
*
* The variant itself is not freed, but any memory used by
* its *value* -- e.g. a string or child variants -- is freed.
*/
void tr_variantClear(tr_variant* clearme);
// --- Serialization / Deserialization
enum tr_variant_fmt
{
TR_VARIANT_FMT_BENC,
TR_VARIANT_FMT_JSON,
TR_VARIANT_FMT_JSON_LEAN /* saves bandwidth by omitting all whitespace. */
};
int tr_variantToFile(tr_variant const* variant, tr_variant_fmt fmt, std::string_view filename);
[[nodiscard]] std::string tr_variantToStr(tr_variant const* variant, tr_variant_fmt fmt);
enum tr_variant_parse_opts
{
TR_VARIANT_PARSE_BENC = (1 << 0),
TR_VARIANT_PARSE_JSON = (1 << 1),
TR_VARIANT_PARSE_INPLACE = (1 << 2)
};
bool tr_variantFromFile(
tr_variant* setme,
tr_variant_parse_opts opts,
std::string_view filename,
struct tr_error** error = nullptr);
bool tr_variantFromBuf(
tr_variant* setme,
int variant_parse_opts,
std::string_view buf,
char const** setme_end = nullptr,
tr_error** error = nullptr);
template<typename T>
bool tr_variantFromBuf(
tr_variant* setme,
int variant_parse_opts,
T const& buf,
char const** setme_end = nullptr,
tr_error** error = nullptr)
{
return tr_variantFromBuf(
setme,
variant_parse_opts,
std::string_view{ std::data(buf), static_cast<size_t>(std::size(buf)) },
setme_end,
error);
}
[[nodiscard]] constexpr bool tr_variantIsType(tr_variant const* b, int type)
{
return b != nullptr && b->type == type;
}
[[nodiscard]] constexpr bool tr_variantIsEmpty(tr_variant const* b)
{
return b == nullptr || b->type == '\0';
}
// --- Strings
[[nodiscard]] constexpr bool tr_variantIsString(tr_variant const* b)
{
return b != nullptr && b->type == TR_VARIANT_TYPE_STR;
}
bool tr_variantGetStrView(tr_variant const* variant, std::string_view* setme);
void tr_variantInitStr(tr_variant* initme, std::string_view value);
void tr_variantInitQuark(tr_variant* initme, tr_quark value);
void tr_variantInitRaw(tr_variant* initme, void const* value, size_t value_len);
void tr_variantInitStrView(tr_variant* initme, std::string_view val);
constexpr void tr_variantInit(tr_variant* initme, char type)
{
initme->val = {};
initme->type = type;
}
bool tr_variantGetRaw(tr_variant const* variant, std::byte const** setme_raw, size_t* setme_len);
bool tr_variantGetRaw(tr_variant const* variant, uint8_t const** setme_raw, size_t* setme_len);
// --- Real Numbers
[[nodiscard]] constexpr bool tr_variantIsReal(tr_variant const* v)
{
return v != nullptr && v->type == TR_VARIANT_TYPE_REAL;
}
bool tr_variantGetReal(tr_variant const* variant, double* value_setme);
constexpr void tr_variantInitReal(tr_variant* initme, double value)
{
tr_variantInit(initme, TR_VARIANT_TYPE_REAL);
initme->val.d = value;
}
// --- Booleans
[[nodiscard]] constexpr bool tr_variantIsBool(tr_variant const* v)
{
return v != nullptr && v->type == TR_VARIANT_TYPE_BOOL;
}
bool tr_variantGetBool(tr_variant const* variant, bool* setme);
constexpr void tr_variantInitBool(tr_variant* initme, bool value)
{
tr_variantInit(initme, TR_VARIANT_TYPE_BOOL);
initme->val.b = value;
}
// --- Ints
[[nodiscard]] constexpr bool tr_variantIsInt(tr_variant const* v)
{
return v != nullptr && v->type == TR_VARIANT_TYPE_INT;
}
bool tr_variantGetInt(tr_variant const* val, int64_t* setme);
constexpr void tr_variantInitInt(tr_variant* initme, int64_t value)
{
tr_variantInit(initme, TR_VARIANT_TYPE_INT);
initme->val.i = value;
}
// --- Lists
[[nodiscard]] constexpr bool tr_variantIsList(tr_variant const* v)
{
return v != nullptr && v->type == TR_VARIANT_TYPE_LIST;
}
void tr_variantInitList(tr_variant* initme, size_t reserve_count);
void tr_variantListReserve(tr_variant* list, size_t reserve_count);
tr_variant* tr_variantListAdd(tr_variant* list);
tr_variant* tr_variantListAddBool(tr_variant* list, bool value);
tr_variant* tr_variantListAddInt(tr_variant* list, int64_t value);
tr_variant* tr_variantListAddReal(tr_variant* list, double value);
tr_variant* tr_variantListAddStr(tr_variant* list, std::string_view value);
tr_variant* tr_variantListAddStrView(tr_variant* list, std::string_view value);
tr_variant* tr_variantListAddQuark(tr_variant* list, tr_quark value);
tr_variant* tr_variantListAddRaw(tr_variant* list, void const* value, size_t value_len);
tr_variant* tr_variantListAddList(tr_variant* list, size_t reserve_count);
tr_variant* tr_variantListAddDict(tr_variant* list, size_t reserve_count);
tr_variant* tr_variantListChild(tr_variant* list, size_t pos);
bool tr_variantListRemove(tr_variant* list, size_t pos);
[[nodiscard]] constexpr size_t tr_variantListSize(tr_variant const* list)
{
return tr_variantIsList(list) ? list->val.l.count : 0;
}
// --- Dictionaries
[[nodiscard]] constexpr bool tr_variantIsDict(tr_variant const* v)
{
return v != nullptr && v->type == TR_VARIANT_TYPE_DICT;
}
void tr_variantInitDict(tr_variant* initme, size_t reserve_count);
void tr_variantDictReserve(tr_variant* dict, size_t reserve_count);
bool tr_variantDictRemove(tr_variant* dict, tr_quark key);
tr_variant* tr_variantDictAdd(tr_variant* dict, tr_quark key);
tr_variant* tr_variantDictAddReal(tr_variant* dict, tr_quark key, double value);
tr_variant* tr_variantDictAddInt(tr_variant* dict, tr_quark key, int64_t value);
tr_variant* tr_variantDictAddBool(tr_variant* dict, tr_quark key, bool value);
tr_variant* tr_variantDictAddStr(tr_variant* dict, tr_quark key, std::string_view value);
tr_variant* tr_variantDictAddStrView(tr_variant* dict, tr_quark key, std::string_view value);
tr_variant* tr_variantDictAddQuark(tr_variant* dict, tr_quark key, tr_quark val);
tr_variant* tr_variantDictAddList(tr_variant* dict, tr_quark key, size_t reserve_count);
tr_variant* tr_variantDictAddDict(tr_variant* dict, tr_quark key, size_t reserve_count);
tr_variant* tr_variantDictSteal(tr_variant* dict, tr_quark key, tr_variant* value);
tr_variant* tr_variantDictAddRaw(tr_variant* dict, tr_quark key, void const* value, size_t len);
bool tr_variantDictChild(tr_variant* dict, size_t pos, tr_quark* setme_key, tr_variant** setme_value);
tr_variant* tr_variantDictFind(tr_variant* dict, tr_quark key);
bool tr_variantDictFindList(tr_variant* dict, tr_quark key, tr_variant** setme);
bool tr_variantDictFindDict(tr_variant* dict, tr_quark key, tr_variant** setme_value);
bool tr_variantDictFindInt(tr_variant* dict, tr_quark key, int64_t* setme);
bool tr_variantDictFindReal(tr_variant* dict, tr_quark key, double* setme);
bool tr_variantDictFindBool(tr_variant* dict, tr_quark key, bool* setme);
bool tr_variantDictFindStrView(tr_variant* dict, tr_quark key, std::string_view* setme);
bool tr_variantDictFindRaw(tr_variant* dict, tr_quark key, uint8_t const** setme_raw, size_t* setme_len);
bool tr_variantDictFindRaw(tr_variant* dict, tr_quark key, std::byte const** setme_raw, size_t* setme_len);
/* this is only quasi-supported. don't rely on it too heavily outside of libT */
void tr_variantMergeDicts(tr_variant* dict_target, tr_variant const* dict_source);
namespace libtransmission
{
struct VariantConverter
{
public:
template<typename T>
static std::optional<T> load(tr_variant* src);
template<typename T>
static void save(tr_variant* tgt, T const& val);
};
} // namespace libtransmission
/* @} */