tomlplusplus/include/toml++/toml_parser.h

472 lines
14 KiB
C++

#pragma once
#include "toml_table.h"
#include "toml_utf8.h"
TOML_START
{
#if TOML_DOXYGEN || !TOML_EXCEPTIONS
/// \brief The result of a parsing operation.
///
/// \detail A parse_result is effectively a discriminated union containing either a toml::table
/// or a toml::parse_error. Most member functions assume a particular one of these two states,
/// and calling them when in the wrong state will cause errors (e.g. attempting to access the
/// error object when parsing was successful). \cpp
/// parse_result result = toml::parse_file("config.toml");
/// if (result)
/// do_stuff_with_a_table(result); //implicitly converts to table&
/// else
/// std::cerr << "Parse failed:\n"sv << result.error() << std::endl;
///
/// \ecpp
///
/// \out
/// example output:
///
/// Parse failed:
/// Encountered unexpected character while parsing boolean; expected 'true', saw 'trU'
/// (error occurred at line 1, column 13 of 'config.toml')
/// \eout
///
/// \attention <strong>This type only exists when exceptions are not enabled.</strong>
/// Otherwise parse_result is just an alias for toml::table: \cpp
/// #if TOML_EXCEPTIONS
/// using parse_result = table;
/// #else
/// class parse_result final { // ...
/// #endif
/// \ecpp
class parse_result final
{
private:
std::aligned_storage_t<
(sizeof(table) < sizeof(parse_error) ? sizeof(parse_error) : sizeof(table)),
(alignof(table) < alignof(parse_error) ? alignof(parse_error) : alignof(table))
> storage;
bool is_err;
void destroy() noexcept
{
if (is_err)
std::launder(reinterpret_cast<parse_error*>(&storage))->~parse_error();
else
std::launder(reinterpret_cast<table*>(&storage))->~table();
}
public:
/// \brief Returns true if parsing succeeeded.
[[nodiscard]] bool succeeded() const noexcept { return !is_err; }
/// \brief Returns true if parsing failed.
[[nodiscard]] bool failed() const noexcept { return is_err; }
/// \brief Returns true if parsing succeeeded.
[[nodiscard]] explicit operator bool() const noexcept { return !is_err; }
/// \brief Returns the internal toml::table.
[[nodiscard]] table& get() & noexcept
{
TOML_ASSERT(!is_err);
return *std::launder(reinterpret_cast<table*>(&storage));
}
/// \brief Returns the internal toml::table (rvalue overload).
[[nodiscard]] table&& get() && noexcept
{
TOML_ASSERT(!is_err);
return std::move(*std::launder(reinterpret_cast<table*>(&storage)));
}
/// \brief Returns the internal toml::table (const lvalue overload).
[[nodiscard]] const table& get() const& noexcept
{
TOML_ASSERT(!is_err);
return *std::launder(reinterpret_cast<const table*>(&storage));
}
/// \brief Returns the internal toml::parse_error.
[[nodiscard]] parse_error& error() & noexcept
{
TOML_ASSERT(is_err);
return *std::launder(reinterpret_cast<parse_error*>(&storage));
}
/// \brief Returns the internal toml::parse_error (rvalue overload).
[[nodiscard]] parse_error&& error() && noexcept
{
TOML_ASSERT(is_err);
return std::move(*std::launder(reinterpret_cast<parse_error*>(&storage)));
}
/// \brief Returns the internal toml::parse_error (const lvalue overload).
[[nodiscard]] const parse_error& error() const& noexcept
{
TOML_ASSERT(is_err);
return *std::launder(reinterpret_cast<const parse_error*>(&storage));
}
/// \brief Returns the internal toml::table.
[[nodiscard]] operator table& () noexcept { return get(); }
/// \brief Returns the internal toml::table (rvalue overload).
[[nodiscard]] operator table&& () noexcept { return std::move(get()); }
/// \brief Returns the internal toml::table (const lvalue overload).
[[nodiscard]] operator const table& () const noexcept { return get(); }
/// \brief Returns the internal toml::parse_error.
[[nodiscard]] explicit operator parse_error& () noexcept { return error(); }
/// \brief Returns the internal toml::parse_error (rvalue overload).
[[nodiscard]] explicit operator parse_error && () noexcept { return std::move(error()); }
/// \brief Returns the internal toml::parse_error (const lvalue overload).
[[nodiscard]] explicit operator const parse_error& () const noexcept { return error(); }
TOML_NODISCARD_CTOR
explicit parse_result(table&& tbl) noexcept
: is_err{ false }
{
::new (&storage) table{ std::move(tbl) };
}
TOML_NODISCARD_CTOR
explicit parse_result(parse_error&& err) noexcept
: is_err{ true }
{
::new (&storage) parse_error{ std::move(err) };
}
/// \brief Move constructor.
TOML_NODISCARD_CTOR
parse_result(parse_result&& res) noexcept
: is_err{ res.is_err }
{
if (is_err)
::new (&storage) parse_error{ std::move(res).error() };
else
::new (&storage) table{ std::move(res).get() };
}
/// \brief Move-assignment operator.
parse_result& operator=(parse_result&& rhs) noexcept
{
if (is_err != rhs.is_err)
{
destroy();
is_err = rhs.is_err;
if (is_err)
::new (&storage) parse_error{ std::move(rhs).error() };
else
::new (&storage) table{ std::move(rhs).get() };
}
else
{
if (is_err)
error() = std::move(rhs).error();
else
get() = std::move(rhs).get();
}
return *this;
}
/// \brief Destructor.
~parse_result() noexcept
{
destroy();
}
};
#else
using parse_result = table;
#endif
}
TOML_END
TOML_IMPL_START
{
[[nodiscard]] TOML_API
parse_result do_parse(utf8_reader_interface&&) TOML_MAY_THROW;
}
TOML_IMPL_END
TOML_START
{
/// \brief Parses a TOML document from a string view.
///
/// \detail \cpp
/// auto tbl = toml::parse("a = 3"sv);
/// std::cout << tbl["a"] << std::endl;
///
/// \ecpp
///
/// \out
/// 3
/// \eout
///
/// \param doc The TOML document to parse. Must be valid UTF-8.
/// \param source_path The path used to initialize each node's `source().path`.
/// If you don't have a path (or you have no intention of using paths in diagnostics)
/// then this parameter can safely be left blank.
///
/// \returns <strong><em>With exceptions:</em></strong> A toml::table. <br>
/// <strong><em>Without exceptions:</em></strong> A toml::parse_result detailing the parsing outcome.
[[nodiscard]] TOML_API
parse_result parse(std::string_view doc, std::string_view source_path = {}) TOML_MAY_THROW;
/// \brief Parses a TOML document from a string view.
///
/// \detail \cpp
/// auto tbl = toml::parse("a = 3"sv, "foo.toml");
/// std::cout << tbl["a"] << std::endl;
///
/// \ecpp
///
/// \out
/// 3
/// \eout
///
/// \param doc The TOML document to parse. Must be valid UTF-8.
/// \param source_path The path used to initialize each node's `source().path`.
///
/// \returns <strong><em>With exceptions:</em></strong> A toml::table. <br>
/// <strong><em>Without exceptions:</em></strong> A toml::parse_result detailing the parsing outcome.
[[nodiscard]] TOML_API
parse_result parse(std::string_view doc, std::string&& source_path) TOML_MAY_THROW;
#if defined(__cpp_lib_char8_t)
/// \brief Parses a TOML document from a char8_t string view.
///
/// \detail \cpp
/// auto tbl = toml::parse(u8"a = 3"sv);
/// std::cout << tbl["a"] << std::endl;
///
/// \ecpp
///
/// \out
/// 3
/// \eout
///
/// \param doc The TOML document to parse. Must be valid UTF-8.
/// \param source_path The path used to initialize each node's `source().path`.
/// If you don't have a path (or you have no intention of using paths in diagnostics)
/// then this parameter can safely be left blank.
///
/// \returns <strong><em>With exceptions:</em></strong> A toml::table. <br>
/// <strong><em>Without exceptions:</em></strong> A toml::parse_result detailing the parsing outcome.
///
/// \attention This overload is not available if your compiler does not support char8_t-based strings.
[[nodiscard]] TOML_API
parse_result parse(std::u8string_view doc, std::string_view source_path = {}) TOML_MAY_THROW;
/// \brief Parses a TOML document from a char8_t string view.
///
/// \detail \cpp
/// auto tbl = toml::parse(u8"a = 3"sv, "foo.toml");
/// std::cout << tbl["a"] << std::endl;
///
/// \ecpp
///
/// \out
/// 3
/// \eout
///
/// \param doc The TOML document to parse. Must be valid UTF-8.
/// \param source_path The path used to initialize each node's `source().path`.
///
/// \returns <strong><em>With exceptions:</em></strong> A toml::table. <br>
/// <strong><em>Without exceptions:</em></strong> A toml::parse_result detailing the parsing outcome.
///
/// \attention This overload is not available if your compiler does not support char8_t-based strings.
[[nodiscard]] TOML_API
parse_result parse(std::u8string_view doc, std::string&& source_path) TOML_MAY_THROW;
#endif // defined(__cpp_lib_char8_t)
/// \brief Parses a TOML document from a stream.
///
/// \detail \cpp
/// std::stringstream ss;
/// ss << "a = 3"sv;
///
/// auto tbl = toml::parse(ss);
/// std::cout << tbl["a"] << std::endl;
///
/// \ecpp
///
/// \out
/// 3
/// \eout
///
/// \tparam CHAR The stream's underlying character type. Must be 1 byte in size.
/// \param doc The TOML document to parse. Must be valid UTF-8.
/// \param source_path The path used to initialize each node's `source().path`.
/// If you don't have a path (or you have no intention of using paths in diagnostics)
/// then this parameter can safely be left blank.
///
/// \returns <strong><em>With exceptions:</em></strong> A toml::table. <br>
/// <strong><em>Without exceptions:</em></strong> A toml::parse_result detailing the parsing outcome.
template <typename CHAR>
[[nodiscard]]
inline parse_result parse(std::basic_istream<CHAR>& doc, std::string_view source_path = {}) TOML_MAY_THROW
{
static_assert(
sizeof(CHAR) == 1,
"The stream's underlying character type must be 1 byte in size."
);
return impl::do_parse(impl::utf8_reader{ doc, source_path });
}
/// \brief Parses a TOML document from a stream.
///
/// \detail \cpp
/// std::stringstream ss;
/// ss << "a = 3"sv;
///
/// auto tbl = toml::parse(ss, "foo.toml");
/// std::cout << tbl["a"] << std::endl;
///
/// \ecpp
///
/// \out
/// 3
/// \eout
///
/// \tparam CHAR The stream's underlying character type. Must be 1 byte in size.
/// \param doc The TOML document to parse. Must be valid UTF-8.
/// \param source_path The path used to initialize each node's `source().path`.
///
/// \returns <strong><em>With exceptions:</em></strong> A toml::table. <br>
/// <strong><em>Without exceptions:</em></strong> A toml::parse_result detailing the parsing outcome.
template <typename CHAR>
[[nodiscard]]
inline parse_result parse(std::basic_istream<CHAR>& doc, std::string&& source_path) TOML_MAY_THROW
{
static_assert(
sizeof(CHAR) == 1,
"The stream's underlying character type must be 1 byte in size."
);
return impl::do_parse(impl::utf8_reader{ doc, std::move(source_path) });
}
/// \brief Parses a TOML document from a file.
///
/// \detail \cpp
/// #include <fstream>
///
/// toml::parse_result get_foo_toml()
/// {
/// return toml::parse_file("foo.toml");
/// }
/// \ecpp
///
/// \tparam CHAR The path's character type. Must be 1 byte in size.
/// \param file_path The TOML document to parse. Must be valid UTF-8.
///
/// \returns <strong><em>With exceptions:</em></strong> A toml::table. <br>
/// <strong><em>Without exceptions:</em></strong> A toml::parse_result detailing the parsing outcome.
///
/// \attention You must `#include <fstream>` to use this function (toml++
/// does not transitively include it for you).
template <typename CHAR>
inline parse_result parse_file(std::basic_string_view<CHAR> file_path) TOML_MAY_THROW
{
static_assert(
sizeof(CHAR) == 1,
"The path's character type must be 1 byte in size."
);
auto str = std::string(reinterpret_cast<const char*>(file_path.data()), file_path.length());
auto ifs = std::basic_ifstream<CHAR>{ str };
return parse( ifs, std::move(str) );
}
// Q: "why are the parse_file functions templated??"
// A: I don't want to force users to drag in <fstream> if they're not going to do
// any parsing directly from files. Keeping them templated delays their instantiation
// until they're actually required, so only those users wanting to use parse_file()
// are burdened by the <fstream> overhead.
template <typename CHAR>
inline parse_result parse_file(const std::basic_string<CHAR>& file_path) TOML_MAY_THROW
{
return parse_file(std::basic_string_view<CHAR>{ file_path });
}
template <typename CHAR>
inline parse_result parse_file(const CHAR* file_path) TOML_MAY_THROW
{
return parse_file(std::basic_string_view<CHAR>{ file_path });
}
/// \brief Convenience literal operators for working with TOML++.
///
/// \detail This namespace exists so you can safely hoist the UDL operators into another scope
/// without dragging in everything in the toml namespace: \cpp
///
/// #include <toml++/toml.h>
/// using namespace toml_literals;
///
/// int main()
/// {
/// auto tbl = "vals = [1, 2, 3]"_toml;
///
/// // ... do stuff with the table generated by the "_toml" UDL ...
///
/// return 0;
/// }
/// \ecpp
///
inline namespace literals
{
/// \brief Parses TOML data from a string.
///
/// \detail \cpp
/// using namespace toml::literals;
///
/// auto tbl = "a = 3"_toml;
/// std::cout << tbl["a"] << std::endl;
///
/// \ecpp
///
/// \out
/// 3
/// \eout
///
/// \param str The string data.
/// \param len The string length.
///
/// \returns <strong><em>With exceptions:</em></strong> A toml::table. <br>
/// <strong><em>Without exceptions:</em></strong> A toml::parse_result detailing the parsing outcome.
[[nodiscard]] TOML_API
parse_result operator"" _toml(const char* str, size_t len) noexcept;
#if defined(__cpp_lib_char8_t)
/// \brief Parses TOML data from a string.
///
/// \detail \cpp
/// using namespace toml::literals;
///
/// auto tbl = u8"a = 3"_toml;
/// std::cout << tbl["a"] << std::endl;
///
/// \ecpp
///
/// \out
/// 3
/// \eout
///
/// \param str The string data.
/// \param len The string length.
///
/// \returns <strong><em>With exceptions:</em></strong> A toml::table. <br>
/// <strong><em>Without exceptions:</em></strong> A toml::parse_result detailing the parsing outcome.
///
/// \attention This overload is not available if your compiler does not support char8_t-based strings.
[[nodiscard]] TOML_API
parse_result operator"" _toml(const char8_t* str, size_t len) noexcept;
#endif
}
}
TOML_END