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diff --git a/deps/sol2/docs/source/api/state.rst b/deps/sol2/docs/source/api/state.rst new file mode 100644 index 0000000..fc8cbff --- /dev/null +++ b/deps/sol2/docs/source/api/state.rst @@ -0,0 +1,205 @@ +state +===== +*owning and non-owning state holders for registry and globals* + + +.. code-block:: cpp + + class state_view; + + class state : state_view, std::unique_ptr<lua_State*, deleter>; + +The most important class here is ``state_view``. This structure takes a ``lua_State*`` that was already created and gives you simple, easy access to Lua's interfaces without taking ownership. ``state`` derives from ``state_view``, inheriting all of this functionality, but has the additional purpose of creating a fresh ``lua_State*`` and managing its lifetime for you in its constructors. + +The majority of the members between ``state_view`` and :doc:`sol::table<table>` are identical, with a few added for this higher-level type. Therefore, all of the examples and notes in :doc:`sol::table<table>` apply here as well. + +``state_view`` is cheap to construct and creates 2 references to things in the ``lua_State*`` while it is alive: the global Lua table, and the Lua C Registry. + +.. _state-automatic-handlers: + +``sol::state`` automatic handlers +--------------------------------- + +One last thing you should understand: constructing a ``sol::state`` does a few things behind-the-scenes for you, mostly to ensure compatibility and good error handler/error handling. The function it uses to do this is ``set_default_state``. They are as follows: + +* set a default panic handler with ``state_view::set_panic``/``lua_atpnic`` +* set a default ``sol::protected_function`` handler with ``sol::protected_function::set_default_handler``, using a ``sol::reference`` to ``&sol::detail::default_traceback_error_handler`` as the default handler function +* set a default exception handler to ``&sol::detail::default_exception_handler`` +* register the state as the main thread (only does something for Lua 5.1, which does not have a way to get the main thread) using ``sol::stack::register_main_thread(L)`` +* register the LuaJIT C function exception handler with ``stack::luajit_exception_handler(L)`` + +You can read up on the various panic and exception handlers on the :ref:`exceptions page<lua-handlers>`. + +sol::state_view does none of these things for you. If you want to make sure your self-created or self-managed state has the same properties, please apply this function once to the state. Please note that it will override your panic handler and, if using LuaJIT, your LuaJIT C function handler. + +.. warning:: + + It is your responsibility to make sure ``sol::state_view`` goes out of scope before you call ``lua_close`` on a pre-existing state, or before ``sol::state`` goes out of scope and its destructor gets called. Failure to do so can result in intermittent crashes because the ``sol::state_view`` has outstanding references to an already-dead ``lua_State*``, and thusly will try to decrement the reference counts for the Lua Registry and the Global Table on a dead state. Please use ``{`` and ``}`` to create a new scope, or other lifetime techniques, when you know you are going to call ``lua_close`` so that you have a chance to specifically control the lifetime of a ``sol::state_view`` object. + +enumerations +------------ + +.. code-block:: cpp + :caption: in-lua libraries + :name: lib-enum + + enum class lib : char { + base, + package, + coroutine, + string, + os, + math, + table, + debug, + bit32, + io, + ffi, + jit, + count // do not use + }; + +This enumeration details the various base libraries that come with Lua. See the `standard lua libraries`_ for details about the various standard libraries. + + +members +------- + +.. code-block:: cpp + :caption: function: open standard libraries/modules + :name: open-libraries + + template<typename... Args> + void open_libraries(Args&&... args); + +This function takes a number of :ref:`sol::lib<lib-enum>` as arguments and opens up the associated Lua core libraries. + +.. code-block:: cpp + :caption: function: script / safe_script / script_file / safe_script_file / unsafe_script / unsafe_script_file + :name: state-script-function + + function_result script(const string_view& code, const std::string& chunk_name = "[string]", load_mode mode = load_mode::any); + protected_function_result script(const string_view& code, const environment& env, const std::string& chunk_name = "[string]", load_mode mode = load_mode::any); + template <typename ErrorFunc> + protected_function_result script(const string_view& code, ErrorFunc&& on_error, const std::string& chunk_name = "[string]", load_mode mode = load_mode::any); + template <typename ErrorFunc> + protected_function_result script(const string_view& code, const environment& env, ErrorFunc&& on_error, const std::string& chunk_name = "[string]", load_mode mode = load_mode::any); + + function_result script_file(const std::string& filename, load_mode mode = load_mode::any); + protected_function_result script_file(const std::string& filename, const environment& env, load_mode mode = load_mode::any); + template <typename ErrorFunc> + protected_function_result script_file(const std::string& filename, ErrorFunc&& on_error, load_mode mode = load_mode::any); + template <typename ErrorFunc> + protected_function_result script_file(const std::string& filename, const environment& env, ErrorFunc&& on_error, load_mode mode = load_mode::any); + +If you need safety, please use the version of these functions with ``safe`` (such as ``safe_script(_file)``) appended in front of them. They will always check for errors and always return a ``sol::protected_function_result``. If you explicitly do not want to check for errors and want to simply invoke ``lua_error`` in the case of errors (which will call ``panic``), use ``unsafe_script(_file)`` versions. + +These functions run the desired blob of either code that is in a string, or code that comes from a filename, on the ``lua_State*``. It will not run isolated: any scripts or code run will affect code in the ``lua_State*`` the object uses as well (unless ``local`` is applied to a variable declaration, as specified by the Lua language). Code ran in this fashion is not isolated. If you need isolation, consider creating a new state or traditional Lua sandboxing techniques. + +If your script returns a value, you can capture it from the returned :ref:`sol::unsafe_function_result<unsafe-function-result>`/:ref:`sol::protected_function_result<protected-function-result>`. Note that the plain versions that do not take an environment or a callback function assume that the contents internally not only loaded properly but ran to completion without errors, for the sake of simplicity and performance. + +To handle errors when using the second overload, provide a callable function/object that takes a ``lua_State*`` as its first argument and a ``sol::protected_function_result`` as its second argument. ``sol::script_default_on_error`` and ``sol::script_pass_on_error`` are 2 functions provided by sol that will either generate a traceback error to return / throw (if throwing is allowed); or, pass the error on through and return it to the user (respectively). An example of having your: + +.. literalinclude:: ../../../examples/source/docs/state_script_safe.cpp + :linenos: + :name: state-script-safe + +You can also pass a :doc:`sol::environment<environment>` to ``script``/``script_file`` to have the script have sandboxed / contained in a way inside of a state. This is useful for runnig multiple different "perspectives" or "views" on the same state, and even has fallback support. See the :doc:`sol::environment<environment>` documentation for more details. + +.. code-block:: cpp + :caption: function: require / require_file + :name: state-require-function + + sol::object require(const std::string& key, lua_CFunction open_function, bool create_global = true); + sol::object require_script(const std::string& key, const std::string& code, bool create_global = true); + sol::object require_file(const std::string& key, const std::string& file, bool create_global = true); + +These functions play a role similar to `luaL_requiref`_ except that they make this functionality available for loading a one-time script or a single file. The code here checks if a module has already been loaded, and if it has not, will either load / execute the file or execute the string of code passed in. If ``create_global`` is set to true, it will also link the name ``key`` to the result returned from the open function, the code or the file. Regardless or whether a fresh load happens or not, the returned module is given as a single :doc:`sol::object<object>` for you to use as you see fit. + +Thanks to `Eric (EToreo) for the suggestion on this one`_! + +.. code-block:: cpp + :caption: function: load / load_file + :name: state-load-code + + sol::load_result load(lua_Reader reader, void* data, const std::string& chunk_name = "[string]", load_mode mode = load_mode::any); + sol::load_result load(const string_view& code, const std::string& chunk_name = "[string]", load_mode mode = load_mode::any); + sol::load_result load_buffer(const char* buff, std::size_t buffsize, const std::string& chunk_name = "[string]", load_mode mode = load_mode::any); + sol::load_result load_file(const std::string& filename, load_mode mode = load_mode::any); + +These functions *load* the desired blob of either code that is in a string, or code that comes from a filename, on the ``lua_State*``. That blob will be turned into a Lua Function. It will not be run: it returns a ``load_result`` proxy that can be called to actually run the code, when you are ready. It can also be turned into a ``sol::function``, a ``sol::protected_function``, or some other abstraction that can serve to call the function. If it is called, it will run on the object's current ``lua_State*``: it is not isolated. If you need isolation, consider using :doc:`sol::environment<environment>`, creating a new state, or other Lua sandboxing techniques. + +Finally, if you have a custom source of data, you can use the ``lua_Reader`` overloaded function alongside passing in a ``void*`` pointing to a single type that has everything you need to run it. Use that callback to provide data to the underlying Lua implementation to read data, as explained `in the Lua manual`_. + +This is a low-level function and if you do not understand the difference between loading a piece of code versus running that code, you should be using :ref:`state_view::script<state-script-function>`. + +.. code-block:: cpp + :caption: function: do_string / do_file + :name: state-do-code + + sol::protected_function_result do_string(const string_view& code); + sol::protected_function_result do_file(const std::string& filename); + sol::protected_function_result do_string(const string_view& code, sol::environment env); + sol::protected_function_result do_file(const std::string& filename, sol::environment env); + +These functions *loads and performs* the desired blob of either code that is in a string, or code that comes from a filename, on the ``lua_State*``. It *will* run, and then return a ``protected_function_result`` proxy that can be examined for either an error or the return value. This function does not provide a callback like :ref:`state_view::script<state-script-function>` does. It is a lower-level function that performs less checking and directly calls ``load(_file)`` before running the result, with the optional environment. + +It is advised that, unless you have specific needs or the callback function is not to your liking, that you work directly with :ref:`state_view::script<state-script-function>`. + +.. code-block:: cpp + :caption: function: global table / registry table + + sol::global_table globals() const; + sol::table registry() const; + +Get either the global table or the Lua registry as a :doc:`sol::table<table>`, which allows you to modify either of them directly. Note that getting the global table from a ``state``/``state_view`` is usually unnecessary as it has all the exact same functions as a :doc:`sol::table<table>` anyhow. + + +.. code-block:: cpp + :caption: function: set_panic + :name: set-panic + + void set_panic(lua_CFunction panic); + +Overrides the panic function Lua calls when something unrecoverable or unexpected happens in the Lua VM. Must be a function of the that matches the ``int(lua_State*)`` function signature. + + +.. code-block:: cpp + :caption: function: memory_used + :name: memory-used + + std::size_t memory_used() const; + +Returns the amount of memory used *in bytes* by the Lua State. + + +.. code-block:: cpp + :caption: function: collect_garbage + :name: collect-garbage + + void collect_garbage(); + +Attempts to run the garbage collector. Note that this is subject to the same rules as the Lua API's collect_garbage function: memory may or may not be freed, depending on dangling references or other things, so make sure you don't have tables or other stack-referencing items currently alive or referenced that you want to be collected. + + +.. code-block:: cpp + :caption: function: make a table + + sol::table create_table(int narr = 0, int nrec = 0); + template <typename Key, typename Value, typename... Args> + sol::table create_table(int narr, int nrec, Key&& key, Value&& value, Args&&... args); + + + template <typename... Args> + sol::table create_table_with(Args&&... args); + + static sol::table create_table(lua_State* L, int narr = 0, int nrec = 0); + template <typename Key, typename Value, typename... Args> + static sol::table create_table(lua_State* L, int narr, int nrec, Key&& key, Value&& value, Args&&... args); + +Creates a table. Forwards its arguments to :ref:`table::create<table-create>`. Applies the same rules as :ref:`table.set<set-value>` when putting the argument values into the table, including how it handles callable objects. + +.. _standard lua libraries: http://www.lua.org/manual/5.3/manual.html#6 +.. _luaL_requiref: https://www.lua.org/manual/5.3/manual.html#luaL_requiref +.. _Eric (EToreo) for the suggestion on this one: https://github.com/ThePhD/sol2/issues/90 +.. _in the Lua manual: https://www.lua.org/manual/5.3/manual.html#lua_Reader |