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Diffstat (limited to 'include/ruby/internal/xmalloc.h')
| -rw-r--r-- | include/ruby/internal/xmalloc.h | 288 |
1 files changed, 288 insertions, 0 deletions
diff --git a/include/ruby/internal/xmalloc.h b/include/ruby/internal/xmalloc.h new file mode 100644 index 0000000000..132bc478ce --- /dev/null +++ b/include/ruby/internal/xmalloc.h @@ -0,0 +1,288 @@ +#ifndef RBIMPL_XMALLOC_H /*-*-C++-*-vi:se ft=cpp:*/ +#define RBIMPL_XMALLOC_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 Declares ::ruby_xmalloc(). + */ +#include "ruby/internal/config.h" + +#ifdef STDC_HEADERS +# include <stddef.h> +#endif + +#ifdef HAVE_STDLIB_H +# include <stdlib.h> +#endif + +#include "ruby/internal/attr/alloc_size.h" +#include "ruby/internal/attr/nodiscard.h" +#include "ruby/internal/attr/noexcept.h" +#include "ruby/internal/attr/restrict.h" +#include "ruby/internal/attr/returns_nonnull.h" +#include "ruby/internal/dllexport.h" + +/** + * @private + * @warning Do not touch this macro. + * @warning It is an implementation detail. + * @warning It was a failure at the first place to let you know about it. + * @warning The value of this macro must match for ruby itself and all + * extension libraries, otherwise serious memory corruption shall + * occur. + */ +#ifndef USE_GC_MALLOC_OBJ_INFO_DETAILS +# define USE_GC_MALLOC_OBJ_INFO_DETAILS 0 +#endif + +#define xmalloc ruby_xmalloc /**< @old{ruby_xmalloc} */ +#define xmalloc2 ruby_xmalloc2 /**< @old{ruby_xmalloc2} */ +#define xcalloc ruby_xcalloc /**< @old{ruby_xcalloc} */ +#define xrealloc ruby_xrealloc /**< @old{ruby_xrealloc} */ +#define xrealloc2 ruby_xrealloc2 /**< @old{ruby_xrealloc2} */ +#define xfree ruby_xfree /**< @old{ruby_xfree} */ + +RBIMPL_SYMBOL_EXPORT_BEGIN() + +RBIMPL_ATTR_NODISCARD() +RBIMPL_ATTR_RESTRICT() +RBIMPL_ATTR_RETURNS_NONNULL() +RBIMPL_ATTR_ALLOC_SIZE((1)) +/** + * Allocates a storage instance. It is largely the same as system malloc(), + * except: + * + * - It raises Ruby exceptions instead of returning NULL, and + * - In case of `ENOMEM` it tries to GC to make some room. + * + * @param[in] size Requested amount of memory. + * @exception rb_eNoMemError No space left for `size` bytes allocation. + * @return A valid pointer to an allocated storage instance; which has at + * least `size` bytes width, with appropriate alignment detected by + * the underlying malloc() routine. + * @note It doesn't return NULL. + * @note Unlike some malloc() implementations, it allocates something and + * returns a meaningful value even when `size` is equal to zero. + * @warning The return value shall be invalidated exactly once by either + * ruby_xfree(), ruby_xrealloc(), or ruby_xrealloc2(). It is a + * failure to pass it to system free(), because the system and Ruby + * might or might not share the same malloc() implementation. + */ +void *ruby_xmalloc(size_t size) +RBIMPL_ATTR_NOEXCEPT(malloc(size)) +; + +RBIMPL_ATTR_NODISCARD() +RBIMPL_ATTR_RESTRICT() +RBIMPL_ATTR_RETURNS_NONNULL() +RBIMPL_ATTR_ALLOC_SIZE((1,2)) +/** + * Identical to ruby_xmalloc(), except it allocates `nelems` * `elemsiz` bytes. + * This is needed because the multiplication could integer overflow. On such + * situations Ruby does not try to allocate at all but raises Ruby level + * exceptions instead. If there is no integer overflow the behaviour is + * exactly the same as `ruby_xmalloc(nelems*elemsiz)`. + * + * @param[in] nelems Number of elements. + * @param[in] elemsiz Size of an element. + * @exception rb_eNoMemError No space left for allocation. + * @exception rb_eArgError `nelems` * `elemsiz` would overflow. + * @return A valid pointer to an allocated storage instance; which has at + * least `nelems` * `elemsiz` bytes width, with appropriate + * alignment detected by the underlying malloc() routine. + * @note It doesn't return NULL. + * @note Unlike some malloc() implementations, it allocates something and + * returns a meaningful value even when `nelems` or `elemsiz` or + * both are zero. + * @warning The return value shall be invalidated exactly once by either + * ruby_xfree(), ruby_xrealloc(), or ruby_xrealloc2(). It is a + * failure to pass it to system free(), because the system and Ruby + * might or might not share the same malloc() implementation. + */ +void *ruby_xmalloc2(size_t nelems, size_t elemsiz) +RBIMPL_ATTR_NOEXCEPT(malloc(nelems * elemsiz)) +; + +RBIMPL_ATTR_NODISCARD() +RBIMPL_ATTR_RESTRICT() +RBIMPL_ATTR_RETURNS_NONNULL() +RBIMPL_ATTR_ALLOC_SIZE((1,2)) +/** + * Identical to ruby_xmalloc2(), except it returns a zero-filled storage + * instance. It can also be seen as a routine identical to ruby_xmalloc(), + * except it calls calloc() instead of malloc(). + * + * @param[in] nelems Number of elements. + * @param[in] elemsiz Size of an element. + * @exception rb_eNoMemError No space left for allocation. + * @exception rb_eArgError `nelems` * `elemsiz` would overflow. + * @return A valid pointer to an allocated storage instance; which has at + * least `nelems` * `elemsiz` bytes width, with appropriate + * alignment detected by the underlying calloc() routine. + * @post The returned storage instance is filled with zeros. + * @note It doesn't return NULL. + * @note Unlike some calloc() implementations, it allocates something and + * returns a meaningful value even when `nelems` or `elemsiz` or + * both are zero. + * @warning The return value shall be invalidated exactly once by either + * ruby_xfree(), ruby_xrealloc(), or ruby_xrealloc2(). It is a + * failure to pass it to system free(), because the system and Ruby + * might or might not share the same malloc() implementation. + */ +void *ruby_xcalloc(size_t nelems, size_t elemsiz) +RBIMPL_ATTR_NOEXCEPT(calloc(nelems, elemsiz)) +; + +RBIMPL_ATTR_NODISCARD() +RBIMPL_ATTR_RETURNS_NONNULL() +RBIMPL_ATTR_ALLOC_SIZE((2)) +/** + * Resize the storage instance. + * + * @param[in] ptr A valid pointer to a storage instance that was + * previously returned from either: + * - ruby_xmalloc(), + * - ruby_xmalloc2(), + * - ruby_xcalloc(), + * - ruby_xrealloc(), or + * - ruby_xrealloc2(). + * @param[in] newsiz Requested new amount of memory. + * @exception rb_eNoMemError No space left for `newsiz` bytes allocation. + * @return A valid pointer to a (possibly newly allocated) storage + * instance; which has at least `newsiz` bytes width, with + * appropriate alignment detected by the underlying realloc() + * routine. + * @pre The passed pointer must point to a valid live storage instance. + * It is a failure to pass an already freed pointer. + * @post In case the function returns the passed pointer as-is, the + * storage instance that the pointer holds is either grown or + * shrunken to have at least `newsiz` bytes. Otherwise a valid + * pointer to a newly allocated storage instance is returned. In + * this case `ptr` is invalidated as if it was passed to + * ruby_xfree(). + * @note It doesn't return NULL. + * @warning Unlike some realloc() implementations, passing zero to `newsiz` + * is not the same as calling ruby_xfree(), because this function + * never returns NULL. Something meaningful still returns then. + * @warning It is a failure not to check the return value. Do not assume + * anything on it. It could be either identical to, or distinct + * form the passed argument. + * @warning Do not assume anything on the alignment of the return value. + * There is no guarantee that it inherits the passed argument's + * one. + * @warning The return value shall be invalidated exactly once by either + * ruby_xfree(), ruby_xrealloc(), or ruby_xrealloc2(). It is a + * failure to pass it to system free(), because the system and Ruby + * might or might not share the same malloc() implementation. + */ +void *ruby_xrealloc(void *ptr, size_t newsiz) +RBIMPL_ATTR_NOEXCEPT(realloc(ptr, newsiz)) +; + +RBIMPL_ATTR_NODISCARD() +RBIMPL_ATTR_RETURNS_NONNULL() +RBIMPL_ATTR_ALLOC_SIZE((2,3)) +/** + * Identical to ruby_xrealloc(), except it resizes the given storage instance + * to `newelems` * `newsiz` bytes. This is needed because the multiplication + * could integer overflow. On such situations Ruby does not try to touch the + * contents of argument pointer at all but raises Ruby level exceptions + * instead. If there is no integer overflow the behaviour is exactly the same + * as `ruby_xrealloc(ptr,nelems*elemsiz)`. + * + * This is roughly the same as reallocarray() function that OpenBSD + * etc. provides, but also interacts with our GC. + * + * @param[in] ptr A valid pointer to a storage instance that was + * previously returned from either: + * - ruby_xmalloc(), + * - ruby_xmalloc2(), + * - ruby_xcalloc(), + * - ruby_xrealloc(), or + * - ruby_xrealloc2(). + * @param[in] newelems Requested new number of elements. + * @param[in] newsiz Requested new size of each element. + * @exception rb_eNoMemError No space left for allocation. + * @exception rb_eArgError `newelems` * `newsiz` would overflow. + * @return A valid pointer to a (possibly newly allocated) storage + * instance; which has at least `newelems` * `newsiz` bytes width, + * with appropriate alignment detected by the underlying realloc() + * routine. + * @pre The passed pointer must point to a valid live storage instance. + * It is a failure to pass an already freed pointer. + * @post In case the function returns the passed pointer as-is, the + * storage instance that the pointer holds is either grown or + * shrunken to have at least `newelems` * `newsiz` bytes. + * Otherwise a valid pointer to a newly allocated storage instance + * is returned. In this case `ptr` is invalidated as if it was + * passed to ruby_xfree(). + * @note It doesn't return NULL. + * @warning Unlike some realloc() implementations, passing zero to either + * `newelems` or `elemsiz` are not the same as calling + * ruby_xfree(), because this function never returns NULL. + * Something meaningful still returns then. + * @warning It is a failure not to check the return value. Do not assume + * anything on it. It could be either identical to, or distinct + * form the passed argument. + * @warning Do not assume anything on the alignment of the return value. + * There is no guarantee that it inherits the passed argument's + * one. + * @warning The return value shall be invalidated exactly once by either + * ruby_xfree(), ruby_xrealloc(), or ruby_xrealloc2(). It is a + * failure to pass it to system free(), because the system and Ruby + * might or might not share the same malloc() implementation. + */ +void *ruby_xrealloc2(void *ptr, size_t newelems, size_t newsiz) +RBIMPL_ATTR_NOEXCEPT(realloc(ptr, newelems * newsiz)) +; + +/** + * Deallocates a storage instance. + * + * @param[out] ptr Either + * - NULL, or + * - a valid pointer previously returned from one of: + * - ruby_xmalloc(), + * - ruby_xmalloc2(), + * - ruby_xcalloc(), + * - ruby_xrealloc(), or + * - ruby_xrealloc2(). + * @pre The passed pointer must point to a valid live storage instance. + * It is a failure to pass an already freed pointer. + * @post The storage instance pointed by the passed pointer gets + * invalidated; it is no longer addressable. + * @warning Every single storage instance that was previously allocated by + * either ruby_xmalloc(), ruby_xmalloc2(), ruby_xcalloc(), + * ruby_xrealloc(), or ruby_xrealloc2() shall be invalidated + * exactly once by either passing it to ruby_xfree(), or passing + * it to either ruby_xrealloc(), ruby_xrealloc2() then check the + * return value for invalidation. + * @warning Do not pass anything other than pointers described above. For + * instance pointers returned from malloc() or mmap() shall not be + * passed to this function, because the underlying memory + * management mechanism could differ. + * @warning Do not pass any invalid pointers to this function e.g. by + * calling it twice with a same argument. + */ +void ruby_xfree(void *ptr) +RBIMPL_ATTR_NOEXCEPT(free(ptr)) +; + +RBIMPL_SYMBOL_EXPORT_END() + +#endif /* RBIMPL_XMALLOC_H */ |