nscore.h
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上传日期:2017-12-03
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- /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
- /* ***** BEGIN LICENSE BLOCK *****
- * Version: MPL 1.1/GPL 2.0/LGPL 2.1
- *
- * The contents of this file are subject to the Mozilla Public License Version
- * 1.1 (the "License"); you may not use this file except in compliance with
- * the License. You may obtain a copy of the License at
- * http://www.mozilla.org/MPL/
- *
- * Software distributed under the License is distributed on an "AS IS" basis,
- * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
- * for the specific language governing rights and limitations under the
- * License.
- *
- * The Original Code is mozilla.org code.
- *
- * The Initial Developer of the Original Code is
- * Netscape Communications Corporation.
- * Portions created by the Initial Developer are Copyright (C) 1998
- * the Initial Developer. All Rights Reserved.
- *
- * Contributor(s):
- *
- * Alternatively, the contents of this file may be used under the terms of
- * either of the GNU General Public License Version 2 or later (the "GPL"),
- * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
- * in which case the provisions of the GPL or the LGPL are applicable instead
- * of those above. If you wish to allow use of your version of this file only
- * under the terms of either the GPL or the LGPL, and not to allow others to
- * use your version of this file under the terms of the MPL, indicate your
- * decision by deleting the provisions above and replace them with the notice
- * and other provisions required by the GPL or the LGPL. If you do not delete
- * the provisions above, a recipient may use your version of this file under
- * the terms of any one of the MPL, the GPL or the LGPL.
- *
- * ***** END LICENSE BLOCK ***** */
- #ifndef nscore_h___
- #define nscore_h___
- /**
- * Make sure that we have the proper platform specific
- * c++ definitions needed by nscore.h
- */
- #ifndef _XPCOM_CONFIG_H_
- #include "xpcom-config.h"
- #endif
- /**
- * Incorporate the core NSPR data types which XPCOM uses.
- */
- #include "prtypes.h"
- /* Core XPCOM declarations. */
- /**
- * Macros defining the target platform...
- */
- #ifdef _WIN32
- #define NS_WIN32 1
- #elif defined(__unix)
- #define NS_UNIX 1
- #elif defined(XP_OS2)
- #define NS_OS2 1
- #endif
- /*----------------------------------------------------------------------*/
- /* Import/export defines */
- /**
- * Using the visibility("hidden") attribute allows the compiler to use
- * PC-relative addressing to call this function. If a function does not
- * access any global data, and does not call any methods which are not either
- * file-local or hidden, then on ELF systems we avoid loading the address of
- * the PLT into a register at the start of the function, which reduces code
- * size and frees up a register for general use.
- *
- * As a general rule, this should be used for any non-exported symbol
- * (including virtual method implementations). NS_IMETHOD uses this by
- * default; if you need to have your NS_IMETHOD functions exported, you can
- * wrap your class as follows:
- *
- * #undef IMETHOD_VISIBILITY
- * #define IMETHOD_VISIBILITY NS_VISIBILITY_DEFAULT
- *
- * class Foo {
- * ...
- * };
- *
- * #undef IMETHOD_VISIBILITY
- * #define IMETHOD_VISIBILITY NS_VISIBILITY_HIDDEN
- *
- * Don't forget to change the visibility back to hidden before the end
- * of a header!
- *
- * Other examples:
- *
- * NS_HIDDEN_(int) someMethod();
- * SomeCtor() NS_HIDDEN;
- */
- #ifdef HAVE_VISIBILITY_HIDDEN_ATTRIBUTE
- #define NS_VISIBILITY_HIDDEN __attribute__ ((visibility ("hidden")))
- #else
- #define NS_VISIBILITY_HIDDEN
- #endif
- #if defined(HAVE_VISIBILITY_HIDDEN_ATTRIBUTE) && defined(HAVE_VISIBILITY_PRAGMA)
- #define NS_VISIBILITY_DEFAULT __attribute__ ((visibility ("default")))
- #else
- #define NS_VISIBILITY_DEFAULT
- #endif
- #define NS_HIDDEN_(type) NS_VISIBILITY_HIDDEN type
- #define NS_EXTERNAL_VIS_(type) NS_VISIBILITY_DEFAULT type
- #define NS_HIDDEN NS_VISIBILITY_HIDDEN
- #define NS_EXTERNAL_VIS NS_VISIBILITY_DEFAULT
- #undef IMETHOD_VISIBILITY
- #define IMETHOD_VISIBILITY NS_VISIBILITY_HIDDEN
- /**
- * Mark a function as using a potentially non-standard function calling
- * convention. This can be used on functions that are called very
- * frequently, to reduce the overhead of the function call. It is still worth
- * using the macro for C++ functions which take no parameters since it allows
- * passing |this| in a register.
- *
- * - Do not use this on any scriptable interface method since xptcall won't be
- * aware of the different calling convention.
- * - This must appear on the declaration, not the definition.
- * - Adding this to a public function _will_ break binary compatibility.
- * - This may be used on virtual functions but you must ensure it is applied
- * to all implementations - the compiler will _not_ warn but it will crash.
- * - This has no effect for inline functions or functions which take a
- * variable number of arguments.
- *
- * Examples: int NS_FASTCALL func1(char *foo);
- * NS_HIDDEN_(int) NS_FASTCALL func2(char *foo);
- */
- #if defined(__i386__) && defined(__GNUC__) && (__GNUC__ >= 3) && !defined(XP_OS2)
- #define NS_FASTCALL __attribute__ ((regparm (3), stdcall))
- #else
- #define NS_FASTCALL
- #endif
- /*
- * NS_DEFCALL undoes the effect of a global regparm/stdcall setting
- * so that xptcall works correctly.
- */
- #if defined(__i386__) && defined(__GNUC__) && (__GNUC__ >= 3) && !defined(XP_OS2)
- #define NS_DEFCALL __attribute__ ((regparm (0), cdecl))
- #else
- #define NS_DEFCALL
- #endif
- #ifdef NS_WIN32
- #define NS_IMPORT __declspec(dllimport)
- #define NS_IMPORT_(type) type __declspec(dllimport) __stdcall
- #define NS_EXPORT __declspec(dllexport)
- #define NS_EXPORT_(type) type __declspec(dllexport) __stdcall
- #define NS_IMETHOD_(type) virtual type __stdcall
- #define NS_IMETHODIMP_(type) type __stdcall
- #define NS_METHOD_(type) type __stdcall
- #define NS_CALLBACK_(_type, _name) _type (__stdcall * _name)
- #define NS_STDCALL __stdcall
- /*
- These are needed to mark static members in exported classes, due to
- gcc bug XXX insert bug# here.
- */
- #define NS_EXPORT_STATIC_MEMBER_(type) type
- #define NS_IMPORT_STATIC_MEMBER_(type) type
- #else
- #define NS_IMPORT NS_EXTERNAL_VIS
- #define NS_IMPORT_(type) NS_EXTERNAL_VIS_(type)
- #define NS_EXPORT NS_EXTERNAL_VIS
- #define NS_EXPORT_(type) NS_EXTERNAL_VIS_(type)
- #define NS_IMETHOD_(type) virtual IMETHOD_VISIBILITY type NS_DEFCALL
- #define NS_IMETHODIMP_(type) type
- #define NS_METHOD_(type) type
- #define NS_CALLBACK_(_type, _name) _type (* _name)
- #define NS_STDCALL
- #define NS_EXPORT_STATIC_MEMBER_(type) NS_EXTERNAL_VIS_(type)
- #define NS_IMPORT_STATIC_MEMBER_(type) NS_EXTERNAL_VIS_(type)
- #endif
- /**
- * Macro for creating typedefs for pointer-to-member types which are
- * declared with stdcall. It is important to use this for any type which is
- * declared as stdcall (i.e. NS_IMETHOD). For example, instead of writing:
- *
- * typedef nsresult (nsIFoo::*someType)(nsISupports* arg);
- *
- * you should write:
- *
- * typedef
- * NS_STDCALL_FUNCPROTO(nsresult, someType, nsIFoo, typeFunc, (nsISupports*));
- *
- * where nsIFoo::typeFunc is any method declared as
- * NS_IMETHOD typeFunc(nsISupports*);
- *
- * XXX this can be simplified to always use the non-typeof implementation
- * when http://gcc.gnu.org/bugzilla/show_bug.cgi?id=11893 is fixed.
- */
- #ifdef __GNUC__
- #define NS_STDCALL_FUNCPROTO(ret, name, class, func, args)
- typeof(&class::func) name
- #else
- #define NS_STDCALL_FUNCPROTO(ret, name, class, func, args)
- ret (NS_STDCALL class::*name) args
- #endif
- /**
- * Generic API modifiers which return the standard XPCOM nsresult type
- */
- #define NS_IMETHOD NS_IMETHOD_(nsresult)
- #define NS_IMETHODIMP NS_IMETHODIMP_(nsresult)
- #define NS_METHOD NS_METHOD_(nsresult)
- #define NS_CALLBACK(_name) NS_CALLBACK_(nsresult, _name)
- /**
- * Import/Export macros for XPCOM APIs
- */
- #ifdef _IMPL_NS_COM
- #define NS_COM NS_EXPORT
- #elif _IMPL_NS_COM_OFF
- #define NS_COM
- #elif XPCOM_GLUE
- #define NS_COM
- #else
- #define NS_COM NS_IMPORT
- #endif
- #ifdef MOZILLA_INTERNAL_API
- # define NS_COM_GLUE NS_COM
- /*
- The frozen string API has different definitions of nsAC?String
- classes than the internal API. On systems that explicitly declare
- dllexport symbols this is not a problem, but on ELF systems
- internal symbols can accidentally "shine through"; we rename the
- internal classes to avoid symbol conflicts.
- */
- # define nsAString nsAString_internal
- # define nsACString nsACString_internal
- #else
- # define NS_COM_GLUE
- #endif
- /**
- * NS_NO_VTABLE is emitted by xpidl in interface declarations whenever
- * xpidl can determine that the interface can't contain a constructor.
- * This results in some space savings and possible runtime savings -
- * see bug 49416. We undefine it first, as xpidl-generated headers
- * define it for IDL uses that don't include this file.
- */
- #ifdef NS_NO_VTABLE
- #undef NS_NO_VTABLE
- #endif
- #if defined(_MSC_VER) && _MSC_VER >= 1100
- #define NS_NO_VTABLE __declspec(novtable)
- #else
- #define NS_NO_VTABLE
- #endif
- /**
- * Generic XPCOM result data type
- */
- typedef PRUint32 nsresult;
- /**
- * The preferred symbol for null.
- */
- #define nsnull 0
- #include "nsError.h"
- /* ------------------------------------------------------------------------ */
- /* Casting macros for hiding C++ features from older compilers */
- /*
- All our compiler support template specialization, but not all support the
- |template <>| notation. The compiler that don't understand this notation
- just omit it for specialization.
- Need to add an autoconf test for this.
- */
- /* under Metrowerks (Mac), we don't have autoconf yet */
- #ifdef __MWERKS__
- #define HAVE_CPP_PARTIAL_SPECIALIZATION
- #define HAVE_CPP_MODERN_SPECIALIZE_TEMPLATE_SYNTAX
- #define HAVE_CPP_ACCESS_CHANGING_USING
- #define HAVE_CPP_AMBIGUITY_RESOLVING_USING
- #define HAVE_CPP_EXPLICIT
- #define HAVE_CPP_TYPENAME
- #define HAVE_CPP_BOOL
- #define HAVE_CPP_NAMESPACE_STD
- #define HAVE_CPP_UNAMBIGUOUS_STD_NOTEQUAL
- #define HAVE_CPP_2BYTE_WCHAR_T
- #endif
- /* under VC++ (Windows), we don't have autoconf yet */
- #if defined(_MSC_VER) && (_MSC_VER>=1100)
- /* VC++ 5.0 and greater implement template specialization, 4.2 is unknown */
- #define HAVE_CPP_MODERN_SPECIALIZE_TEMPLATE_SYNTAX
- #define HAVE_CPP_EXPLICIT
- #define HAVE_CPP_TYPENAME
- #define HAVE_CPP_ACCESS_CHANGING_USING
- #if (_MSC_VER==1100)
- /* VC++5.0 has an internal compiler error (sometimes) without this */
- #undef HAVE_CPP_ACCESS_CHANGING_USING
- #endif
- #define HAVE_CPP_NAMESPACE_STD
- #define HAVE_CPP_UNAMBIGUOUS_STD_NOTEQUAL
- #define HAVE_CPP_2BYTE_WCHAR_T
- #endif
- #ifndef __PRUNICHAR__
- #define __PRUNICHAR__
- /* For now, don't use wchar_t on Unix because it breaks the Netscape
- * commercial build. When this is fixed there will be no need for the
- * |NS_REINTERPRET_CAST| in nsLiteralString.h either.
- */
- #if defined(HAVE_CPP_2BYTE_WCHAR_T) && defined(NS_WIN32)
- typedef wchar_t PRUnichar;
- #else
- typedef PRUint16 PRUnichar;
- #endif
- #endif
- /*
- If the compiler doesn't support |explicit|, we'll just make it go away, trusting
- that the builds under compilers that do have it will keep us on the straight and narrow.
- */
- #ifndef HAVE_CPP_EXPLICIT
- #define explicit
- #endif
- #ifndef HAVE_CPP_TYPENAME
- #define typename
- #endif
- #ifdef HAVE_CPP_MODERN_SPECIALIZE_TEMPLATE_SYNTAX
- #define NS_SPECIALIZE_TEMPLATE template <>
- #else
- #define NS_SPECIALIZE_TEMPLATE
- #endif
- /* unix and beos now determine this automatically */
- #if ! defined XP_UNIX && ! defined XP_BEOS && !defined(XP_OS2)
- #ifndef HAVE_CPP_NEW_CASTS
- #define HAVE_CPP_NEW_CASTS 1 /* we'll be optimistic. */
- #endif
- #endif
- #if defined(HAVE_CPP_NEW_CASTS)
- #define NS_STATIC_CAST(__type, __ptr) static_cast< __type >(__ptr)
- #define NS_CONST_CAST(__type, __ptr) const_cast< __type >(__ptr)
- #define NS_REINTERPRET_POINTER_CAST(__type, __ptr) reinterpret_cast< __type >(__ptr)
- #define NS_REINTERPRET_NONPOINTER_CAST(__type, __obj) reinterpret_cast< __type >(__obj)
- #define NS_REINTERPRET_CAST(__type, __expr) reinterpret_cast< __type >(__expr)
- #else
- #define NS_STATIC_CAST(__type, __ptr) ((__type)(__ptr))
- #define NS_CONST_CAST(__type, __ptr) ((__type)(__ptr))
- #define NS_REINTERPRET_POINTER_CAST(__type, __ptr) ((__type)((void*)(__ptr)))
- #define NS_REINTERPRET_NONPOINTER_CAST(__type, __obj) ((__type)(__obj))
- /* Note: the following is only appropriate for pointers. */
- #define NS_REINTERPRET_CAST(__type, __expr) NS_REINTERPRET_POINTER_CAST(__type, __expr)
- /*
- Why cast to a |void*| first? Well, when old-style casting from
- a pointer to a base to a pointer to a derived class, the cast will be
- ambiguous if the source pointer type appears multiple times in the
- destination, e.g.,
-
- class Base {};
- class Derived : public Base, public Base {};
-
- void foo( Base* b )
- {
- ((Derived*)b)->some_derived_member ... // Error: Ambiguous, expand from which |Base|?
- }
- an old-style cast (like |static_cast|) will change the pointer, but
- here, doesn't know how. The cast to |void*| prevents it from thinking
- it needs to expand the original pointer.
- The cost is, |NS_REINTERPRET_CAST| is no longer appropriate for non-pointer
- conversions. Also, mis-applying |NS_REINTERPRET_CAST| to cast |this| to something
- will still expand the pointer to the outer object in standards complying compilers.
- */
- /*
- No sense in making an NS_DYNAMIC_CAST() macro: you can't duplicate
- the semantics. So if you want to dynamic_cast, then just use it
- "straight", no macro.
- */
- #endif
-
- /*
- * Use these macros to do 64bit safe pointer conversions.
- */
- #define NS_PTR_TO_INT32(x) ((PRInt32) (PRWord) (x))
- #define NS_PTR_TO_UINT32(x) ((PRUint32) (PRWord) (x))
- #define NS_INT32_TO_PTR(x) ((void *) (PRWord) (x))
- /*
- * Use NS_STRINGIFY to form a string literal from the value of a macro.
- */
- #define NS_STRINGIFY_HELPER(x_) #x_
- #define NS_STRINGIFY(x_) NS_STRINGIFY_HELPER(x_)
- /*
- * These macros allow you to give a hint to the compiler about branch
- * probability so that it can better optimize. Use them like this:
- *
- * if (NS_LIKELY(v == 1)) {
- * ... expected code path ...
- * }
- *
- * if (NS_UNLIKELY(v == 0)) {
- * ... non-expected code path ...
- * }
- *
- */
- #if defined(__GNUC__) && (__GNUC__ > 2)
- #define NS_LIKELY(x) (__builtin_expect((x), 1))
- #define NS_UNLIKELY(x) (__builtin_expect((x), 0))
- #else
- #define NS_LIKELY(x) (x)
- #define NS_UNLIKELY(x) (x)
- #endif
- #endif /* nscore_h___ */