diff options
Diffstat (limited to 'include/ruby/internal/core/rbasic.h')
| -rw-r--r-- | include/ruby/internal/core/rbasic.h | 172 |
1 files changed, 172 insertions, 0 deletions
diff --git a/include/ruby/internal/core/rbasic.h b/include/ruby/internal/core/rbasic.h new file mode 100644 index 0000000000..63cdff8e09 --- /dev/null +++ b/include/ruby/internal/core/rbasic.h @@ -0,0 +1,172 @@ +#ifndef RBIMPL_RBASIC_H /*-*-C++-*-vi:se ft=cpp:*/ +#define RBIMPL_RBASIC_H +/** + * @file + * @author Ruby developers <ruby-core@ruby-lang.org> + * @copyright This file is a part of the programming language Ruby. + * Permission is hereby granted, to either redistribute and/or + * modify this file, provided that the conditions mentioned in the + * file COPYING are met. Consult the file for details. + * @warning Symbols prefixed with either `RBIMPL` or `rbimpl` are + * implementation details. Don't take them as canon. They could + * rapidly appear then vanish. The name (path) of this header file + * is also an implementation detail. Do not expect it to persist + * at the place it is now. Developers are free to move it anywhere + * anytime at will. + * @note To ruby-core: remember that this header can be possibly + * recursively included from extension libraries written in C++. + * Do not expect for instance `__VA_ARGS__` is always available. + * We assume C99 for ruby itself but we don't assume languages of + * extension libraries. They could be written in C++98. + * @brief Defines struct ::RBasic. + */ +#include "ruby/internal/attr/artificial.h" +#include "ruby/internal/attr/constexpr.h" +#include "ruby/internal/attr/forceinline.h" +#include "ruby/internal/attr/noalias.h" +#include "ruby/internal/attr/pure.h" +#include "ruby/internal/cast.h" +#include "ruby/internal/dllexport.h" +#include "ruby/internal/special_consts.h" +#include "ruby/internal/value.h" +#include "ruby/assert.h" + +/** + * Convenient casting macro. + * + * @param obj Arbitrary Ruby object. + * @return The passed object casted to ::RBasic. + */ +#define RBASIC(obj) RBIMPL_CAST((struct RBasic *)(obj)) +/** @cond INTERNAL_MACRO */ +#define RBASIC_CLASS RBASIC_CLASS +#define RBIMPL_RVALUE_EMBED_LEN_MAX 3 +#define RVALUE_EMBED_LEN_MAX RVALUE_EMBED_LEN_MAX +#define RBIMPL_EMBED_LEN_MAX_OF(T) \ + RBIMPL_CAST((int)(sizeof(VALUE[RBIMPL_RVALUE_EMBED_LEN_MAX]) / (sizeof(T)))) +/** @endcond */ + +/** + * This is an enum because GDB wants it (rather than a macro). People need not + * bother. + */ +enum ruby_rvalue_flags { + /** Max possible number of objects that can be embedded. */ + RVALUE_EMBED_LEN_MAX = RBIMPL_RVALUE_EMBED_LEN_MAX +}; + +#if (SIZEOF_VALUE < SIZEOF_UINT64_T) +#define RBASIC_SHAPE_ID_FIELD 1 +#else +#define RBASIC_SHAPE_ID_FIELD 0 +#endif + +/** + * Ruby object's base components. All Ruby objects have them in common. + */ +struct +RUBY_ALIGNAS(SIZEOF_VALUE) +RBasic { + + /** + * Per-object flags. Each Ruby object has its own characteristics apart + * from its class. For instance, whether an object is frozen or not is not + * controlled by its class. This is where such properties are stored. + * + * @see enum ::ruby_fl_type + * + * @note This is ::VALUE rather than an enum for alignment purposes. Back + * in the 1990s there were no such thing like `_Alignas` in C. + */ + VALUE flags; + + /** + * Class of an object. Every object has its class. Also, everything is an + * object in Ruby. This means classes are also objects. Classes have + * their own classes, classes of classes have their classes too, and it + * recursively continues forever. + * + * Also note the `const` qualifier. In Ruby, an object cannot "change" its + * class. + */ + const VALUE klass; + +#if RBASIC_SHAPE_ID_FIELD + VALUE shape_id; +#endif + +#ifdef __cplusplus + public: + RBIMPL_ATTR_CONSTEXPR(CXX11) + RBIMPL_ATTR_ARTIFICIAL() + RBIMPL_ATTR_FORCEINLINE() + RBIMPL_ATTR_NOALIAS() + /** + * We need to define this explicit constructor because the field `klass` is + * const-qualified above, which effectively defines the implicit default + * constructor as "deleted" (as of C++11) -- No way but to define one by + * ourselves. + */ + RBasic() : + flags(RBIMPL_VALUE_NULL), + klass(RBIMPL_VALUE_NULL) +#if RBASIC_SHAPE_ID_FIELD + , shape_id(RBIMPL_VALUE_NULL) +#endif + { + } +# define RBASIC_INIT RBasic() +#else +# define RBASIC_INIT {RBIMPL_VALUE_NULL} +#endif +}; + +RBIMPL_SYMBOL_EXPORT_BEGIN() +/** + * Make the object invisible from Ruby code. + * + * It is useful to let Ruby's GC manage your internal data structure -- The + * object keeps being managed by GC, but `ObjectSpace.each_object` never yields + * the object. + * + * Note that the object also lose a way to call a method on it. + * + * @param[out] obj A Ruby object. + * @return The passed object. + * @post The object is destructively modified to be invisible. + * @see rb_obj_reveal + */ +VALUE rb_obj_hide(VALUE obj); + +/** + * Make a hidden object visible again. + * + * It is the caller's responsibility to pass the right `klass` which `obj` + * originally used to belong to. + * + * @param[out] obj A Ruby object. + * @param[in] klass Class of `obj`. + * @return Passed `obj`. + * @pre `obj` was previously hidden. + * @post `obj`'s class is `klass`. + * @see rb_obj_hide + */ +VALUE rb_obj_reveal(VALUE obj, VALUE klass); /* do not use this API to change klass information */ +RBIMPL_SYMBOL_EXPORT_END() + +RBIMPL_ATTR_PURE_UNLESS_DEBUG() +RBIMPL_ATTR_ARTIFICIAL() +/** + * Queries the class of an object. + * + * @param[in] obj An object. + * @return Its class. + */ +static inline VALUE +RBASIC_CLASS(VALUE obj) +{ + RBIMPL_ASSERT_OR_ASSUME(! RB_SPECIAL_CONST_P(obj)); + return RBASIC(obj)->klass; +} + +#endif /* RBIMPL_RBASIC_H */ |