forked from mirrors/gecko-dev
38a6de0fe3
I'm not sure how I tested MOZ_FOR_EACH in bug 1368932, but it turns out it doesn't work with an empty list, despite MOZ_PASTE_PREFIX_AND_ARG_COUNT now supporting 0 arguments. Macros can be tricky, and it ends up being easier to make things work cross-compiler with a separate macro that does the counting, and (re)building MOZ_PASTE_PREFIX_AND_ARG_COUNT on top of that. Then MOZ_FOR_EACH ends up working as expected with an empty list. So this adds a MOZ_ARG_COUNT macro that counts the number of variadic arguments it's given, and derives MOZ_PASTE_PREFIX_AND_ARG_COUNT from it. And this adds a testcase validating that MOZ_FOR_EACH works properly with an empty list as a result. --HG-- extra : rebase_source : 309371d87bd1561fbd2153f44fc1256185045d23
50 lines
1.9 KiB
C++
50 lines
1.9 KiB
C++
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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/* vim: set ts=8 sts=2 et sw=2 tw=80: */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#include "mozilla/Assertions.h"
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#include "mozilla/MacroForEach.h"
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#define HELPER_IDENTITY(x) x
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#define HELPER_IDENTITY_PLUS(x) x +
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static_assert(MOZ_FOR_EACH(HELPER_IDENTITY_PLUS, (), (10)) 0 == 10, "");
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static_assert(MOZ_FOR_EACH(HELPER_IDENTITY_PLUS, (), (1, 1, 1)) 0 == 3, "");
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static_assert(MOZ_FOR_EACH_SEPARATED(HELPER_IDENTITY, (+),
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(), (10)) == 10, "");
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static_assert(MOZ_FOR_EACH_SEPARATED(HELPER_IDENTITY, (+),
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(), (1, 1, 1)) == 3, "");
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#define HELPER_ONE_PLUS(x) HELPER_IDENTITY_PLUS(1)
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static_assert(MOZ_FOR_EACH(HELPER_ONE_PLUS, (), ()) 0 == 0, "");
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#define HELPER_DEFINE_VAR(x) const int test1_##x = x;
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MOZ_FOR_EACH(HELPER_DEFINE_VAR, (), (10, 20))
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static_assert(test1_10 == 10 && test1_20 == 20, "");
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#define HELPER_DEFINE_VAR2(k, x) const int test2_##x = k + x;
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MOZ_FOR_EACH(HELPER_DEFINE_VAR2, (5,), (10, 20))
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static_assert(test2_10 == 15 && test2_20 == 25, "");
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#define HELPER_DEFINE_PARAM(t, n) t n
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constexpr int
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test(MOZ_FOR_EACH_SEPARATED(HELPER_DEFINE_PARAM, (,), (int,), (a, b, c)))
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{
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return a + b + c;
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}
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static_assert(test(1, 2, 3) == 6, "");
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int
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main()
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{
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#define HELPER_IDENTITY_COMMA(k1, k2, x) k1, k2, x,
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const int a[] = {
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MOZ_FOR_EACH(HELPER_IDENTITY_COMMA, (1, 2,), (10, 20, 30))
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};
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MOZ_RELEASE_ASSERT(a[0] == 1 && a[1] == 2 && a[2] == 10 &&
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a[3] == 1 && a[4] == 2 && a[5] == 20 &&
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a[6] == 1 && a[7] == 2 && a[8] == 30,
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"MOZ_FOR_EACH args enumerated in incorrect order");
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return 0;
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}
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