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SERVER-42894 Create SourceLocation type and related macros
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‎src/mongo/platform/SConscript‎

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@@ -13,6 +13,7 @@ env.CppUnitTest(
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'mutex_test.cpp',
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'process_id_test.cpp',
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'random_test.cpp',
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'source_location_test.cpp',
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'stack_locator_test.cpp',
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'decimal128_test.cpp',
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'decimal128_bson_test.cpp',

‎src/mongo/platform/source_location.h‎

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/**
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* Copyright (C) 2019-present MongoDB, Inc.
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the Server Side Public License, version 1,
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* as published by MongoDB, Inc.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* Server Side Public License for more details.
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*
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* You should have received a copy of the Server Side Public License
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* along with this program. If not, see
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* <http://www.mongodb.com/licensing/server-side-public-license>.
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*
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* As a special exception, the copyright holders give permission to link the
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* code of portions of this program with the OpenSSL library under certain
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* conditions as described in each individual source file and distribute
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* linked combinations including the program with the OpenSSL library. You
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* must comply with the Server Side Public License in all respects for
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* all of the code used other than as permitted herein. If you modify file(s)
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* with this exception, you may extend this exception to your version of the
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* file(s), but you are not obligated to do so. If you do not wish to do so,
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* delete this exception statement from your version. If you delete this
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* exception statement from all source files in the program, then also delete
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* it in the license file.
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*/
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#pragma once
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#include <cstdint>
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#include <string>
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#if !defined(_MSC_VER) && !defined(__clang__) // not windows or clang
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#include <experimental/source_location>
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#endif // windows
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#include <fmt/format.h>
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namespace mongo {
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/**
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* A SourceLocation is a constexpr type that captures a source location
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*
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* This class mimics the api signature of C++20 std::source_location
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*
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* It is intended to be constructed with MONGO_SOURCE_LOCATION() below.
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*/
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class SourceLocation {
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public:
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constexpr SourceLocation(uint_least32_t line,
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uint_least32_t column,
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const char* file_name,
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const char* function_name) noexcept
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: _line(line), _column(column), _file_name(file_name), _function_name(function_name) {}
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constexpr uint_least32_t line() const noexcept {
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return _line;
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}
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constexpr uint_least32_t column() const noexcept {
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return _column;
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}
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constexpr const char* file_name() const noexcept {
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return _file_name;
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}
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constexpr const char* function_name() const noexcept {
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return _function_name;
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}
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private:
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uint_least32_t _line;
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uint_least32_t _column; // column will be 0 if there isn't compiler support
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const char* _file_name;
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const char* _function_name;
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};
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/**
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* SourceLocationHolder is intended for convenient io of SourceLocation
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*/
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class SourceLocationHolder {
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public:
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constexpr SourceLocationHolder(SourceLocation&& loc) noexcept
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: _loc(std::forward<SourceLocation>(loc)) {}
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constexpr uint_least32_t line() const noexcept {
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return _loc.line();
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}
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constexpr uint_least32_t column() const noexcept {
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return _loc.column();
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}
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constexpr const char* file_name() const noexcept {
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return _loc.file_name();
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}
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constexpr const char* function_name() const noexcept {
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return _loc.function_name();
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}
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std::string toString() const {
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using namespace fmt::literals;
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return R"({{fileName:"{}", line:{}, functionName:"{}"}})"_format(
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_loc.file_name(), _loc.line(), _loc.function_name());
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}
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friend std::ostream& operator<<(std::ostream& out, const SourceLocationHolder& context) {
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return out << context.toString();
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}
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private:
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SourceLocation _loc;
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};
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/**
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* MONGO_SOURCE_LOCATION() either:
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* - captures std::experimental::source_location::current()
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* - makes a best effort with various macros and local static constants
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*
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* Since __FUNCSIG__ and __PRETTY_FUNCTION__ aren't defined outside of functions, there is also
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* MONGO_SOURCE_LOCATION_NO_FUNC() for use with a default member initializatizer or constant
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* initialization.
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*/
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#if defined(_MSC_VER) // windows
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// MSVC does not have any of N4810 yet. (see
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// https://developercommunity.visualstudio.com/idea/354069/implement-c-library-fundamentals-ts-v2.html)
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#define MONGO_SOURCE_LOCATION() SourceLocation(__LINE__, 0ul, __FILE__, __func__)
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#define MONGO_SOURCE_LOCATION_NO_FUNC() SourceLocation(__LINE__, 0ul, __FILE__, "")
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#elif defined(__clang__) // windows -> clang
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// Clang got __builtin_FILE et al as of 8.0.1 (see https://reviews.llvm.org/D37035)
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#define MONGO_SOURCE_LOCATION() SourceLocation(__LINE__, 0ul, __FILE__, __func__)
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#define MONGO_SOURCE_LOCATION_NO_FUNC() SourceLocation(__LINE__, 0ul, __FILE__, "")
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#elif defined(__GNUG__) // clang -> gcc
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constexpr auto toSourceLocation(std::experimental::source_location loc) {
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// Note that std::experimental::source_location captures __func__, not __PRETTY_FUNC__
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return SourceLocation(loc.line(), loc.column(), loc.file_name(), loc.function_name());
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}
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#define MONGO_SOURCE_LOCATION() toSourceLocation(std::experimental::source_location::current())
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#define MONGO_SOURCE_LOCATION_NO_FUNC() \
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toSourceLocation(std::experimental::source_location::current())
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#else // gcc -> ?
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#error "Unknown compiler, cannot approximate std::source_location"
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#endif // ?
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} // namespace mongo

‎src/mongo/platform/source_location_test.cpp‎

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/**
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* Copyright (C) 2019-present MongoDB, Inc.
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the Server Side Public License, version 1,
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* as published by MongoDB, Inc.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* Server Side Public License for more details.
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*
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* You should have received a copy of the Server Side Public License
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* along with this program. If not, see
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* <http://www.mongodb.com/licensing/server-side-public-license>.
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*
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* As a special exception, the copyright holders give permission to link the
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* code of portions of this program with the OpenSSL library under certain
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* conditions as described in each individual source file and distribute
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* linked combinations including the program with the OpenSSL library. You
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* must comply with the Server Side Public License in all respects for
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* all of the code used other than as permitted herein. If you modify file(s)
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* with this exception, you may extend this exception to your version of the
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* file(s), but you are not obligated to do so. If you do not wish to do so,
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* delete this exception statement from your version. If you delete this
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* exception statement from all source files in the program, then also delete
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* it in the license file.
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*/
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#include "mongo/platform/basic.h"
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#include "mongo/platform/source_location_test.h"
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namespace mongo {
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namespace {
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constexpr SourceLocation makeLocalFunctionSourceLocationForTest() {
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return MONGO_SOURCE_LOCATION();
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}
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const SourceLocationHolder kLocation = MONGO_SOURCE_LOCATION_NO_FUNC();
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struct StructWithDefaultInitContextMember {
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const SourceLocationHolder location = MONGO_SOURCE_LOCATION_NO_FUNC();
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};
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#define CALL_MONGO_SOURCE_LOCATION() MONGO_SOURCE_LOCATION()
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TEST(SourceLocation, CorrectLineNumber) {
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using LineT = std::invoke_result_t<decltype(&SourceLocation::line), SourceLocation>;
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ASSERT_EQ(MONGO_SOURCE_LOCATION().line(), static_cast<LineT>(__LINE__));
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}
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TEST(SourceLocation, InlineVariable) {
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SourceLocationHolder inlineLocation1 = MONGO_SOURCE_LOCATION();
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SourceLocationHolder inlineLocation2 = MONGO_SOURCE_LOCATION();
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SourceLocationHolder inlineLocation3 = MONGO_SOURCE_LOCATION();
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// Each location should have the same filename
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ASSERT_EQ(inlineLocation1.file_name(), inlineLocation2.file_name());
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ASSERT_EQ(inlineLocation1.file_name(), inlineLocation3.file_name());
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// The line numbers for each location should increase monotonically when inline
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ASSERT_LT(inlineLocation1.line(), inlineLocation2.line());
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ASSERT_LT(inlineLocation2.line(), inlineLocation3.line());
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unittest::log() << inlineLocation1;
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unittest::log() << inlineLocation2;
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unittest::log() << inlineLocation3;
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}
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TEST(SourceLocation, LocalFunction) {
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SourceLocationHolder inlineLocation1 = MONGO_SOURCE_LOCATION();
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SourceLocationHolder localFunctionLocation1 = makeLocalFunctionSourceLocationForTest();
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SourceLocationHolder localFunctionLocation2 = makeLocalFunctionSourceLocationForTest();
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// The inline location should have the same file name but a later line
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ASSERT_EQ(inlineLocation1.file_name(), localFunctionLocation1.file_name());
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ASSERT_GT(inlineLocation1.line(), localFunctionLocation1.line());
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// The two local function locations should be identical
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ASSERT_EQ(localFunctionLocation1, localFunctionLocation2);
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unittest::log() << inlineLocation1;
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unittest::log() << localFunctionLocation1;
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unittest::log() << localFunctionLocation2;
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}
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TEST(SourceLocation, HeaderFunction) {
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SourceLocationHolder inlineLocation1 = MONGO_SOURCE_LOCATION();
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SourceLocationHolder headerLocation1 = makeHeaderSourceLocationForTest();
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SourceLocationHolder headerLocation2 = makeHeaderSourceLocationForTest();
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// The inline location should have a different file name
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ASSERT_NE(inlineLocation1.file_name(), headerLocation1.file_name());
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// The two header locations should be identical
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ASSERT_EQ(headerLocation1, headerLocation2);
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unittest::log() << inlineLocation1;
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unittest::log() << headerLocation1;
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unittest::log() << headerLocation2;
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}
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TEST(SourceLocation, GlobalVariable) {
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SourceLocationHolder inlineLocation1 = MONGO_SOURCE_LOCATION();
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// The inline location should have the same file name but a later line
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ASSERT_EQ(inlineLocation1.file_name(), kLocation.file_name());
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ASSERT_GT(inlineLocation1.line(), kLocation.line());
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unittest::log() << inlineLocation1;
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unittest::log() << kLocation;
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}
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TEST(SourceLocation, DefaultStructMember) {
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SourceLocationHolder inlineLocation1 = MONGO_SOURCE_LOCATION();
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StructWithDefaultInitContextMember obj1;
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StructWithDefaultInitContextMember obj2;
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// The inline location should have the same file name but a later line
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ASSERT_EQ(inlineLocation1.file_name(), obj1.location.file_name());
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ASSERT_GT(inlineLocation1.line(), obj1.location.line());
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// The two default ctor'd struct member locations should be identical
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ASSERT_EQ(obj1.location, obj2.location);
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unittest::log() << inlineLocation1;
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unittest::log() << obj1.location;
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unittest::log() << obj2.location;
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}
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TEST(SourceLocation, Macro) {
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SourceLocationHolder inlineLocation1 = MONGO_SOURCE_LOCATION();
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SourceLocationHolder inlineLocation2 = CALL_MONGO_SOURCE_LOCATION();
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// Each location should have the same filename
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ASSERT_EQ(inlineLocation1.file_name(), inlineLocation2.file_name());
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// The line numbers for each location should increase monotonically when inline
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ASSERT_LT(inlineLocation1.line(), inlineLocation2.line());
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unittest::log() << inlineLocation1;
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unittest::log() << inlineLocation2;
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}
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TEST(SourceLocation, Constexpr) {
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constexpr SourceLocationHolder inlineLocation1 = MONGO_SOURCE_LOCATION();
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constexpr SourceLocationHolder inlineLocation2 = MONGO_SOURCE_LOCATION();
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static_assert((inlineLocation1.line() + 1) == inlineLocation2.line());
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static_assert(inlineLocation1.column() == inlineLocation2.column());
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static_assert(areEqual(inlineLocation1.file_name(), inlineLocation2.file_name()));
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static_assert(areEqual(inlineLocation1.function_name(), inlineLocation2.function_name()));
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constexpr auto localFunctionLocation = makeLocalFunctionSourceLocationForTest();
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static_assert(inlineLocation1.line() > localFunctionLocation.line());
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static_assert(areEqual(inlineLocation1.file_name(), localFunctionLocation.file_name()));
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static_assert(
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!areEqual(inlineLocation1.function_name(), localFunctionLocation.function_name()));
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constexpr auto headerLocation = makeHeaderSourceLocationForTest();
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static_assert(!areEqual(inlineLocation1.file_name(), headerLocation.file_name()));
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static_assert(!areEqual(inlineLocation1.function_name(), headerLocation.function_name()));
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}
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} // namespace
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} // namespace mongo

‎src/mongo/platform/source_location_test.h‎

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/**
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* Copyright (C) 2019-present MongoDB, Inc.
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the Server Side Public License, version 1,
6+
* as published by MongoDB, Inc.
7+
*
8+
* This program is distributed in the hope that it will be useful,
9+
* but WITHOUT ANY WARRANTY; without even the implied warranty of
10+
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11+
* Server Side Public License for more details.
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*
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* You should have received a copy of the Server Side Public License
14+
* along with this program. If not, see
15+
* <http://www.mongodb.com/licensing/server-side-public-license>.
16+
*
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* As a special exception, the copyright holders give permission to link the
18+
* code of portions of this program with the OpenSSL library under certain
19+
* conditions as described in each individual source file and distribute
20+
* linked combinations including the program with the OpenSSL library. You
21+
* must comply with the Server Side Public License in all respects for
22+
* all of the code used other than as permitted herein. If you modify file(s)
23+
* with this exception, you may extend this exception to your version of the
24+
* file(s), but you are not obligated to do so. If you do not wish to do so,
25+
* delete this exception statement from your version. If you delete this
26+
* exception statement from all source files in the program, then also delete
27+
* it in the license file.
28+
*/
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#pragma once
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#include "mongo/unittest/unittest.h"
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#include "mongo/platform/source_location.h"
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namespace mongo {
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inline bool operator==(const SourceLocationHolder& lhs, const SourceLocationHolder& rhs) {
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return lhs.line() == rhs.line() //
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&& lhs.column() == rhs.column() //
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&& lhs.file_name() == rhs.file_name() //
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&& lhs.function_name() == rhs.function_name();
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}
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inline bool operator!=(const SourceLocationHolder& lhs, const SourceLocationHolder& rhs) {
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return !(lhs == rhs);
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}
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// Simple recursive constexpr string comparison to play nice with static_assert
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constexpr bool areEqual(const char* string1, const char* string2) {
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return (string1 != nullptr) //
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&& (string2 != nullptr) //
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&& *string1 == *string2 //
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&& (*string1 == '\0' || areEqual(string1 + 1, string2 + 1));
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}
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inline constexpr SourceLocation makeHeaderSourceLocationForTest() {
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return MONGO_SOURCE_LOCATION();
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}
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} // namespace mongo

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