зеркало из https://github.com/mozilla/pjs.git
387 строки
14 KiB
C++
387 строки
14 KiB
C++
/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
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* vim: set ts=8 sw=4 et tw=99 ft=cpp:
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*
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* ***** BEGIN LICENSE BLOCK *****
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* Version: MPL 1.1/GPL 2.0/LGPL 2.1
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*
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* The contents of this file are subject to the Mozilla Public License Version
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* 1.1 (the "License"); you may not use this file except in compliance with
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* the License. You may obtain a copy of the License at:
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* http://www.mozilla.org/MPL/
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*
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* Software distributed under the License is distributed on an "AS IS" basis,
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* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
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* for the specific language governing rights and limitations under the
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* License.
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*
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* The Original Code is Mozilla Code.
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*
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* The Initial Developer of the Original Code is
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* The Mozilla Foundation
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* Portions created by the Initial Developer are Copyright (C) 2011
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* the Initial Developer. All Rights Reserved.
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*
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* Contributor(s):
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* Jeff Walden <jwalden+code@mit.edu>
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*
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* Alternatively, the contents of this file may be used under the terms of
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* either the GNU General Public License Version 2 or later (the "GPL"), or
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* the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
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* in which case the provisions of the GPL or the LGPL are applicable instead
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* of those above. If you wish to allow use of your version of this file only
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* under the terms of either the GPL or the LGPL, and not to allow others to
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* use your version of this file under the terms of the MPL, indicate your
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* decision by deleting the provisions above and replace them with the notice
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* and other provisions required by the GPL or the LGPL. If you do not delete
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* the provisions above, a recipient may use your version of this file under
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* the terms of any one of the MPL, the GPL or the LGPL.
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*
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* ***** END LICENSE BLOCK ***** */
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/* Implementations of runtime and static assertion macros for C and C++. */
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#ifndef mozilla_Assertions_h_
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#define mozilla_Assertions_h_
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#include "mozilla/Attributes.h"
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#include "mozilla/Types.h"
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#include <stdio.h>
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#include <stdlib.h>
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#ifndef WIN32
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# include <signal.h>
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#endif
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#ifdef ANDROID
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# include <android/log.h>
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#endif
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/*
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* MOZ_STATIC_ASSERT may be used to assert a condition *at compile time*. This
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* can be useful when you make certain assumptions about what must hold for
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* optimal, or even correct, behavior. For example, you might assert that the
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* size of a struct is a multiple of the target architecture's word size:
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*
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* struct S { ... };
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* MOZ_STATIC_ASSERT(sizeof(S) % sizeof(size_t) == 0,
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* "S should be a multiple of word size for efficiency");
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*
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* This macro can be used in any location where both an extern declaration and a
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* typedef could be used.
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*
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* Be aware of the gcc 4.2 concerns noted further down when writing patches that
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* use this macro, particularly if a patch only bounces on OS X.
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*/
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#ifdef __cplusplus
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# if defined(__clang__)
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# ifndef __has_extension
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# define __has_extension __has_feature /* compatibility, for older versions of clang */
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# endif
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# if __has_extension(cxx_static_assert)
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# define MOZ_STATIC_ASSERT(cond, reason) static_assert((cond), reason)
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# endif
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# elif defined(__GNUC__)
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# if (defined(__GXX_EXPERIMENTAL_CXX0X__) || __cplusplus >= 201103L) && \
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(__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 3))
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# define MOZ_STATIC_ASSERT(cond, reason) static_assert((cond), reason)
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# endif
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# elif defined(_MSC_VER)
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# if _MSC_VER >= 1600 /* MSVC 10 */
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# define MOZ_STATIC_ASSERT(cond, reason) static_assert((cond), reason)
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# endif
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# elif defined(__HP_aCC)
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# if __HP_aCC >= 62500 && defined(_HP_CXX0x_SOURCE)
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# define MOZ_STATIC_ASSERT(cond, reason) static_assert((cond), reason)
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# endif
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# endif
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#endif
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#ifndef MOZ_STATIC_ASSERT
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# define MOZ_STATIC_ASSERT_GLUE1(x, y) x##y
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# define MOZ_STATIC_ASSERT_GLUE(x, y) MOZ_STATIC_ASSERT_GLUE1(x, y)
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# if defined(__SUNPRO_CC)
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/*
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* The Sun Studio C++ compiler is buggy when declaring, inside a function,
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* another extern'd function with an array argument whose length contains a
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* sizeof, triggering the error message "sizeof expression not accepted as
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* size of array parameter". This bug (6688515, not public yet) would hit
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* defining moz_static_assert as a function, so we always define an extern
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* array for Sun Studio.
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*
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* We include the line number in the symbol name in a best-effort attempt
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* to avoid conflicts (see below).
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*/
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# define MOZ_STATIC_ASSERT(cond, reason) \
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extern char MOZ_STATIC_ASSERT_GLUE(moz_static_assert, __LINE__)[(cond) ? 1 : -1]
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# elif defined(__COUNTER__)
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/*
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* If there was no preferred alternative, use a compiler-agnostic version.
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*
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* Note that the non-__COUNTER__ version has a bug in C++: it can't be used
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* in both |extern "C"| and normal C++ in the same translation unit. (Alas
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* |extern "C"| isn't allowed in a function.) The only affected compiler
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* we really care about is gcc 4.2. For that compiler and others like it,
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* we include the line number in the function name to do the best we can to
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* avoid conflicts. These should be rare: a conflict would require use of
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* MOZ_STATIC_ASSERT on the same line in separate files in the same
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* translation unit, *and* the uses would have to be in code with
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* different linkage, *and* the first observed use must be in C++-linkage
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* code.
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*/
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# define MOZ_STATIC_ASSERT(cond, reason) \
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typedef int MOZ_STATIC_ASSERT_GLUE(moz_static_assert, __COUNTER__)[(cond) ? 1 : -1]
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# else
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# define MOZ_STATIC_ASSERT(cond, reason) \
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extern void MOZ_STATIC_ASSERT_GLUE(moz_static_assert, __LINE__)(int arg[(cond) ? 1 : -1])
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# endif
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#endif
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#define MOZ_STATIC_ASSERT_IF(cond, expr, reason) MOZ_STATIC_ASSERT(!(cond) || (expr), reason)
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#ifdef __cplusplus
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extern "C" {
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#endif
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#if defined(WIN32)
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/*
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* We used to call DebugBreak() on Windows, but amazingly, it causes
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* the MSVS 2010 debugger not to be able to recover a call stack.
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*/
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# define MOZ_CRASH() \
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do { \
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*((volatile int *) NULL) = 123; \
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exit(3); \
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} while (0)
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#elif defined(ANDROID)
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/*
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* On Android, raise(SIGABRT) is handled asynchronously. Seg fault now
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* so we crash immediately and capture the current call stack. We need
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* to specifically use the global namespace in the C++ case.
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*/
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# ifdef __cplusplus
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# define MOZ_CRASH() \
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do { \
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*((volatile int *) NULL) = 123; \
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::abort(); \
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} while (0)
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# else
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# define MOZ_CRASH() \
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do { \
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*((volatile int *) NULL) = 123; \
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abort(); \
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} while (0)
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# endif
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#elif defined(__APPLE__)
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/*
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* On Mac OS X, Breakpad ignores signals. Only real Mach exceptions are
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* trapped.
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*/
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# define MOZ_CRASH() \
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do { \
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*((volatile int *) NULL) = 123; \
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raise(SIGABRT); /* In case above statement gets nixed by the optimizer. */ \
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} while (0)
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#else
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# define MOZ_CRASH() \
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do { \
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raise(SIGABRT); /* To continue from here in GDB: "signal 0". */ \
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} while (0)
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#endif
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extern MFBT_API(void)
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MOZ_Assert(const char* s, const char* file, int ln);
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static MOZ_ALWAYS_INLINE void
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MOZ_OutputAssertMessage(const char* s, const char *file, int ln)
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{
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#ifdef ANDROID
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__android_log_print(ANDROID_LOG_FATAL, "MOZ_Assert",
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"Assertion failure: %s, at %s:%d\n", s, file, ln);
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#else
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fprintf(stderr, "Assertion failure: %s, at %s:%d\n", s, file, ln);
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fflush(stderr);
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#endif
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}
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#ifdef __cplusplus
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} /* extern "C" */
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#endif
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/*
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* MOZ_ASSERT(expr [, explanation-string]) asserts that |expr| must be truthy in
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* debug builds. If it is, execution continues. Otherwise, an error message
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* including the expression and the explanation-string (if provided) is printed,
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* an attempt is made to invoke any existing debugger, and execution halts.
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* MOZ_ASSERT is fatal: no recovery is possible. Do not assert a condition
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* which can correctly be falsy.
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*
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* The optional explanation-string, if provided, must be a string literal
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* explaining the assertion. It is intended for use with assertions whose
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* correctness or rationale is non-obvious, and for assertions where the "real"
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* condition being tested is best described prosaically. Don't provide an
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* explanation if it's not actually helpful.
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*
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* // No explanation needed: pointer arguments often must not be NULL.
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* MOZ_ASSERT(arg);
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*
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* // An explanation can be helpful to explain exactly how we know an
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* // assertion is valid.
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* MOZ_ASSERT(state == WAITING_FOR_RESPONSE,
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* "given that <thingA> and <thingB>, we must have...");
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*
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* // Or it might disambiguate multiple identical (save for their location)
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* // assertions of the same expression.
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* MOZ_ASSERT(getSlot(PRIMITIVE_THIS_SLOT).isUndefined(),
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* "we already set [[PrimitiveThis]] for this Boolean object");
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* MOZ_ASSERT(getSlot(PRIMITIVE_THIS_SLOT).isUndefined(),
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* "we already set [[PrimitiveThis]] for this String object");
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*
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* MOZ_ASSERT has no effect in non-debug builds. It is designed to catch bugs
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* *only* during debugging, not "in the field".
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*/
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#ifdef DEBUG
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/* First the single-argument form. */
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# define MOZ_ASSERT_HELPER1(expr) \
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do { \
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if (!(expr)) { \
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MOZ_OutputAssertMessage(#expr, __FILE__, __LINE__); \
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MOZ_CRASH(); \
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} \
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} while (0)
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/* Now the two-argument form. */
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# define MOZ_ASSERT_HELPER2(expr, explain) \
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do { \
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if (!(expr)) { \
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MOZ_OutputAssertMessage(#expr " (" explain ")", __FILE__, __LINE__); \
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MOZ_CRASH(); \
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} \
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} while (0)
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/* And now, helper macrology up the wazoo. */
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/*
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* Count the number of arguments passed to MOZ_ASSERT, very carefully
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* tiptoeing around an MSVC bug where it improperly expands __VA_ARGS__ as a
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* single token in argument lists. See these URLs for details:
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*
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* http://connect.microsoft.com/VisualStudio/feedback/details/380090/variadic-macro-replacement
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* http://cplusplus.co.il/2010/07/17/variadic-macro-to-count-number-of-arguments/#comment-644
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*/
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# define MOZ_COUNT_ASSERT_ARGS_IMPL2(_1, _2, count, ...) \
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count
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# define MOZ_COUNT_ASSERT_ARGS_IMPL(args) \
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MOZ_COUNT_ASSERT_ARGS_IMPL2 args
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# define MOZ_COUNT_ASSERT_ARGS(...) \
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MOZ_COUNT_ASSERT_ARGS_IMPL((__VA_ARGS__, 2, 1, 0))
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/* Pick the right helper macro to invoke. */
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# define MOZ_ASSERT_CHOOSE_HELPER2(count) MOZ_ASSERT_HELPER##count
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# define MOZ_ASSERT_CHOOSE_HELPER1(count) MOZ_ASSERT_CHOOSE_HELPER2(count)
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# define MOZ_ASSERT_CHOOSE_HELPER(count) MOZ_ASSERT_CHOOSE_HELPER1(count)
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/* The actual macro. */
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# define MOZ_ASSERT_GLUE(x, y) x y
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# define MOZ_ASSERT(...) \
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MOZ_ASSERT_GLUE(MOZ_ASSERT_CHOOSE_HELPER(MOZ_COUNT_ASSERT_ARGS(__VA_ARGS__)), \
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(__VA_ARGS__))
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#else
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# define MOZ_ASSERT(...) do { } while(0)
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#endif /* DEBUG */
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/*
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* MOZ_ASSERT_IF(cond1, cond2) is equivalent to MOZ_ASSERT(cond2) if cond1 is
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* true.
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*
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* MOZ_ASSERT_IF(isPrime(num), num == 2 || isOdd(num));
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*
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* As with MOZ_ASSERT, MOZ_ASSERT_IF has effect only in debug builds. It is
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* designed to catch bugs during debugging, not "in the field".
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*/
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#ifdef DEBUG
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# define MOZ_ASSERT_IF(cond, expr) \
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do { \
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if (cond) \
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MOZ_ASSERT(expr); \
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} while (0)
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#else
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# define MOZ_ASSERT_IF(cond, expr) do { } while (0)
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#endif
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/* MOZ_NOT_REACHED_MARKER() expands (in compilers which support it) to an
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* expression which states that it is undefined behavior for the compiler to
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* reach this point. Most code should probably use the higher level
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* MOZ_NOT_REACHED (which expands to this when appropriate).
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*/
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#if defined(__clang__)
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# define MOZ_NOT_REACHED_MARKER() __builtin_unreachable()
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#elif defined(__GNUC__)
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# if __GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 5)
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# define MOZ_NOT_REACHED_MARKER() __builtin_unreachable()
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# endif
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#elif defined(_MSC_VER)
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# define MOZ_NOT_REACHED_MARKER() __assume(0)
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#endif
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/*
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* MOZ_NOT_REACHED(reason) indicates that the given point can't be reached
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* during execution: simply reaching that point in execution is a bug. It takes
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* as an argument an error message indicating the reason why that point should
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* not have been reachable.
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*
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* // ...in a language parser...
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* void handle(BooleanLiteralNode node)
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* {
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* if (node.isTrue())
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* handleTrueLiteral();
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* else if (node.isFalse())
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* handleFalseLiteral();
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* else
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* MOZ_NOT_REACHED("boolean literal that's not true or false?");
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* }
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*/
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#if defined(MOZ_NOT_REACHED_MARKER)
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# if defined(DEBUG)
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# define MOZ_NOT_REACHED(reason) do { \
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MOZ_Assert(reason, __FILE__, __LINE__); \
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MOZ_NOT_REACHED_MARKER(); \
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} while (0)
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# else
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# define MOZ_NOT_REACHED(reason) MOZ_NOT_REACHED_MARKER()
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# endif
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#else
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# if defined(__GNUC__)
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/*
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* On older versions of gcc we need to call a noreturn function to mark the
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* code as unreachable. Since what we want is an unreachable version of
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* MOZ_Assert, we use an asm label
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* (http://gcc.gnu.org/onlinedocs/gcc-4.6.2/gcc/Asm-Labels.html) to create
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* a new declaration to the same symbol. MOZ_ASSERT_NR should only be
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* used via this macro, as it is a very specific hack to older versions of
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* gcc.
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*/
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# define MOZ_GETASMPREFIX2(X) #X
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# define MOZ_GETASMPREFIX(X) MOZ_GETASMPREFIX2(X)
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# define MOZ_ASMPREFIX MOZ_GETASMPREFIX(__USER_LABEL_PREFIX__)
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extern MOZ_NORETURN MFBT_API(void)
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MOZ_ASSERT_NR(const char* s, const char* file, int ln) \
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asm (MOZ_ASMPREFIX "MOZ_Assert");
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# define MOZ_NOT_REACHED(reason) MOZ_ASSERT_NR(reason, __FILE__, __LINE__)
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# elif defined(DEBUG)
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# define MOZ_NOT_REACHED(reason) MOZ_Assert(reason, __FILE__, __LINE__)
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# else
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# define MOZ_NOT_REACHED(reason) ((void)0)
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# endif
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#endif
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/*
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* MOZ_ALWAYS_TRUE(expr) and MOZ_ALWAYS_FALSE(expr) always evaluate the provided
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* expression, in debug builds and in release builds both. Then, in debug
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* builds only, the value of the expression is asserted either true or false
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* using MOZ_ASSERT.
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*/
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#ifdef DEBUG
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# define MOZ_ALWAYS_TRUE(expr) MOZ_ASSERT((expr))
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# define MOZ_ALWAYS_FALSE(expr) MOZ_ASSERT(!(expr))
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#else
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# define MOZ_ALWAYS_TRUE(expr) ((void)(expr))
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# define MOZ_ALWAYS_FALSE(expr) ((void)(expr))
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#endif
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#endif /* mozilla_Assertions_h_ */
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