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ruby--ruby/include/ruby/internal/symbol.h
卜部昌平 73d2bf97c1 include/ruby/internal/symbol.h: add doxygen 
Must not be a bad idea to improve documents. [ci skip]
2021-09-10 20:00:06 +09:00

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#ifndef RBIMPL_SYMBOL_H /*-*-C++-*-vi:se ft=cpp:*/
#define RBIMPL_SYMBOL_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 #rb_intern
*/
#include "ruby/internal/config.h"
#ifdef STDC_HEADERS
# include <stddef.h>
#endif
#ifdef HAVE_STRING_H
# include <string.h>
#endif
#include "ruby/internal/attr/noalias.h"
#include "ruby/internal/attr/nonnull.h"
#include "ruby/internal/attr/pure.h"
#include "ruby/internal/cast.h"
#include "ruby/internal/constant_p.h"
#include "ruby/internal/dllexport.h"
#include "ruby/internal/has/builtin.h"
#include "ruby/internal/value.h"
#define RB_ID2SYM rb_id2sym /**< @alias{rb_id2sym} */
#define RB_SYM2ID rb_sym2id /**< @alias{rb_sym2id} */
#define ID2SYM RB_ID2SYM /**< @old{RB_ID2SYM} */
#define SYM2ID RB_SYM2ID /**< @old{RB_SYM2ID} */
#define CONST_ID_CACHE RUBY_CONST_ID_CACHE /**< @old{RUBY_CONST_ID_CACHE} */
#define CONST_ID RUBY_CONST_ID /**< @old{RUBY_CONST_ID} */
/** @cond INTERNAL_MACRO */
#define rb_intern_const rb_intern_const
/** @endcond */
RBIMPL_SYMBOL_EXPORT_BEGIN()
/**
* Converts an instance of ::rb_cSymbol into an ::ID.
*
* @param[in] obj An instance of ::rb_cSymbol.
* @exception rb_eTypeError `obj` is not an instance of ::rb_cSymbol.
* @return An ::ID of the identical symbol.
*/
ID rb_sym2id(VALUE obj);
/**
* Allocates an instance of ::rb_cSymbol that has the given id.
*
* @param[in] id An id.
* @retval RUBY_Qfalse No such id ever existed in the history.
* @retval Otherwise An allocated ::rb_cSymbol instance.
*/
VALUE rb_id2sym(ID id);
RBIMPL_ATTR_NONNULL(())
/**
* Finds or creates a symbol of the given name.
*
* @param[in] name The name of the id.
* @exception rb_eRuntimeError Too many symbols.
* @return A (possibly new) id whose value is the given name.
* @note These days Ruby internally has two kinds of symbols (static /
* dynamic). Symbols created using this function would become a
* static one; i.e. would never be garbage collected. It is up to
* you to avoid memory leaks. Think twice before using it.
*/
ID rb_intern(const char *name);
/**
* Identical to rb_intern(), except it additionally takes the length of the
* string. This way you can have a symbol that contains NUL characters.
*
* @param[in] name The name of the id.
* @param[in] len Length of `name`.
* @exception rb_eRuntimeError Too many symbols.
* @return A (possibly new) id whose value is the given name.
* @note These days Ruby internally has two kinds of symbols
* (static/dynamic). Symbols created using this function would
* become static ones; i.e. would never be garbage collected. It
* is up to you to avoid memory leaks. Think twice before using
* it.
*/
ID rb_intern2(const char *name, long len);
/**
* Identical to rb_intern(), except it takes an instance of ::rb_cString.
*
* @param[in] str The name of the id.
* @pre `str` must either be an instance of ::rb_cSymbol, or an instance
* of ::rb_cString, or responds to `#to_str` method.
* @exception rb_eTypeError Can't convert `str` into ::rb_cString.
* @exception rb_eRuntimeError Too many symbols.
* @return A (possibly new) id whose value is the given str.
* @note These days Ruby internally has two kinds of symbols
* (static/dynamic). Symbols created using this function would
* become static ones; i.e. would never be garbage collected. It
* is up to you to avoid memory leaks. Think twice before using
* it.
*/
ID rb_intern_str(VALUE str);
/**
* Retrieves the name mapped to the given id.
*
* @param[in] id An id to query.
* @retval NULL No such id ever existed in the history.
* @retval otherwise A name that the id represents.
* @note The return value is managed by the interpreter. Don't pass it
* to free().
*/
const char *rb_id2name(ID id);
RBIMPL_ATTR_NONNULL(())
/**
* Detects if the given name is already interned or not. It first tries to
* convert the argument to an instance of ::rb_cString if it is neither an
* instance of ::rb_cString nor ::rb_cSymbol. The conversion result is written
* back to the variable. Then queries if that name was already interned
* before. If found it returns such id, otherwise zero.
*
* We eventually introduced this API to avoid inadvertent symbol pin-down.
* Before, there was no way to know if an ID was already interned or not
* without actually creating one (== leaking memory). By using this API you
* can avoid such situations:
*
* ```CXX
* bool does_interning_this_leak_memory(VALUE obj)
* {
* auto tmp = obj;
* if (auto id = rb_check_id(&tmp); id) {
* return false;
* }
* else {
* return true; // Let GC sweep tmp if necessary.
* }
* }
* ```
*
* @param[in,out] namep A pointer to a name to query.
* @pre The object referred by `*namep` must either be an instance
* of ::rb_cSymbol, or an instance of ::rb_cString, or responds
* to `#to_str` method.
* @exception rb_eTypeError Can't convert `*namep` into ::rb_cString.
* @exception rb_eEncodingError Given string is non-ASCII.
* @retval 0 No such id ever existed in the history.
* @retval otherwise The id that represents the given name.
* @post The object that `*namep` points to is a converted result
* object, which is always an instance of either ::rb_cSymbol
* or ::rb_cString.
* @see https://bugs.ruby-lang.org/issues/5072
*
* @internal
*
* @shyouhei doesn't know why this has to raise rb_eEncodingError.
*/
ID rb_check_id(volatile VALUE *namep);
/**
* @copydoc rb_intern_str()
*
* @internal
*
* :FIXME: Can anyone tell us what is the difference between this one and
* rb_intern_str()? As far as @shyouhei reads the implementation it seems what
* rb_to_id() does is is just waste some CPU time, then call rb_intern_str().
* He hopes he is wrong.
*/
ID rb_to_id(VALUE str);
/**
* Identical to rb_id2name(), except it returns a Ruby's String instead of C's.
*
* @param[in] id An id to query.
* @retval RUBY_Qfalse No such id ever existed in the history.
* @retval otherwise An instance of ::rb_cString with the name of id.
*
* @internal
*
* In reality "rb_id2str() is identical to rb_id2name() except it returns Ruby
* string" is just describing things upside down; truth is `rb_id2name(foo)` is
* a shorthand of `RSTRING_PTR(rb_id2str(foo))`.
*/
VALUE rb_id2str(ID id);
/**
* Identical to rb_id2str(), except it takes an instance of ::rb_cSymbol rather
* than an ::ID.
*
* @param[in] id An id to query.
* @retval RUBY_Qfalse No such id ever existed in the history.
* @retval otherwise An instance of ::rb_cString with the name of id.
*/
VALUE rb_sym2str(VALUE id);
/**
* Identical to rb_intern_str(), except it generates a dynamic symbol if
* necessary.
*
* @param[in] name The name of the id.
* @pre `name` must either be an instance of ::rb_cSymbol, or an
* instance of ::rb_cString, or responds to `#to_str` method.
* @exception rb_eTypeError Can't convert `name` into ::rb_cString.
* @exception rb_eRuntimeError Too many symbols.
* @return A (possibly new) id whose value is the given name.
* @note These days Ruby internally has two kinds of symbols
* (static/dynamic). Symbols created using this function would
* become dynamic ones; i.e. would be garbage collected. It could
* be safer for you to use it than alternatives, when applicable.
*/
VALUE rb_to_symbol(VALUE name);
RBIMPL_ATTR_NONNULL(())
/**
* Identical to rb_check_id(), except it returns an instance of ::rb_cSymbol
* instead.
*
* @param[in,out] namep A pointer to a name to query.
* @pre The object referred by `*namep` must either be an instance
* of ::rb_cSymbol, or an instance of ::rb_cString, or responds
* to `#to_str` method.
* @exception rb_eTypeError Can't convert `*namep` into ::rb_cString.
* @exception rb_eEncodingError Given string is non-ASCII.
* @retval RUBY_Qnil No such id ever existed in the history.
* @retval otherwise The id that represents the given name.
* @post The object that `*namep` points to is a converted result
* object, which is always an instance of either ::rb_cSymbol
* or ::rb_cString.
* @see https://bugs.ruby-lang.org/issues/5072
*
* @internal
*
* @shyouhei doesn't know why this has to raise rb_eEncodingError.
*/
VALUE rb_check_symbol(volatile VALUE *namep);
RBIMPL_SYMBOL_EXPORT_END()
RBIMPL_ATTR_PURE()
RBIMPL_ATTR_NONNULL(())
/**
* This is a "tiny optimisation" over rb_intern(). If you pass a string
* _literal_, and if your C compiler can special-case strlen of such literal to
* strength-reduce into an integer constant expression, then this inline
* function can precalc a part of conversion.
*
* @note This function also works happily for non-constant strings. Why
* bother then? Just apply liberally to everything.
* @note But #rb_intern() could be faster on compilers with statement
* expressions, because they can cache the created ::ID.
* @param[in] str The name of the id.
* @exception rb_eRuntimeError Too many symbols.
* @return A (possibly new) id whose value is the given str.
* @note These days Ruby internally has two kinds of symbols (static /
* dynamic). Symbols created using this function would become a
* static one; i.e. would never be garbage collected. It is up to
* you to avoid memory leaks. Think twice before using it.
*/
static inline ID
rb_intern_const(const char *str)
{
size_t len = strlen(str);
return rb_intern2(str, RBIMPL_CAST((long)len));
}
RBIMPL_ATTR_NOALIAS()
RBIMPL_ATTR_NONNULL(())
/**
* @private
*
* This is an implementation detail of #rb_intern(). Just don't use it.
*/
static inline ID
rbimpl_intern_const(ID *ptr, const char *str)
{
while (! *ptr) {
*ptr = rb_intern_const(str);
}
return *ptr;
}
/**
* Old implementation detail of rb_intern().
* @deprecated Does anyone use it? Preserved for backward compat.
*/
#define RUBY_CONST_ID_CACHE(result, str) \
{ \
static ID rb_intern_id_cache; \
rbimpl_intern_const(&rb_intern_id_cache, (str)); \
result rb_intern_id_cache; \
}
/**
* Old implementation detail of rb_intern().
* @deprecated Does anyone use it? Preserved for backward compat.
*/
#define RUBY_CONST_ID(var, str) \
do { \
static ID rbimpl_id; \
(var) = rbimpl_intern_const(&rbimpl_id, (str)); \
} while (0)
#if defined(HAVE_STMT_AND_DECL_IN_EXPR)
/* __builtin_constant_p and statement expression is available
* since gcc-2.7.2.3 at least. */
#define rb_intern(str) \
(RBIMPL_CONSTANT_P(str) ? \
__extension__ ({ \
static ID rbimpl_id; \
rbimpl_intern_const(&rbimpl_id, (str)); \
}) : \
(rb_intern)(str))
#endif
#endif /* RBIMPL_SYMBOL_H */
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