SERVER-17631 add makeStatusWith factory function

src/mongo/base/SConscript

@@ -30,6 +30,7 @@ env.CppUnitTest('base_test',
                  'owned_pointer_map_test.cpp',
                  'parse_number_test.cpp',
                  'status_test.cpp',
+                 'status_with_test.cpp',
                  'encoded_value_storage_test.cpp',
                  'data_view_test.cpp',
                  'data_cursor_test.cpp',

src/mongo/base/status_with.h

@@ -31,6 +31,7 @@
 
 #include <iosfwd>
 #include <type_traits>
+#include <utility>
 
 #include "mongo/base/status.h"
 
@@ -124,6 +125,11 @@ namespace mongo {
         T _t;
     };
 
+    template<typename T, typename... Args>
+    StatusWith<T> makeStatusWith(Args&&... args) {
+        return StatusWith<T>{T(std::forward<Args>(args)...)};
+    }
+
     template<typename T>
     std::ostream& operator<<(std::ostream& stream, const StatusWith<T>& sw) {
         if (sw.isOK())

src/mongo/base/status_with_test.cpp

@@ -0,0 +1,78 @@
+/**
+ *    Copyright (C) 2015 MongoDB Inc.
+ *
+ *    This program is free software: you can redistribute it and/or  modify
+ *    it under the terms of the GNU Affero General Public License, version 3,
+ *    as published by the Free Software Foundation.
+ *
+ *    This program is distributed in the hope that it will be useful,
+ *    but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *    GNU Affero General Public License for more details.
+ *
+ *    You should have received a copy of the GNU Affero General Public License
+ *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ *    As a special exception, the copyright holders give permission to link the
+ *    code of portions of this program with the OpenSSL library under certain
+ *    conditions as described in each individual source file and distribute
+ *    linked combinations including the program with the OpenSSL library. You
+ *    must comply with the GNU Affero General Public License in all respects
+ *    for all of the code used other than as permitted herein. If you modify
+ *    file(s) with this exception, you may extend this exception to your
+ *    version of the file(s), but you are not obligated to do so. If you do not
+ *    wish to do so, delete this exception statement from your version. If you
+ *    delete this exception statement from all source files in the program,
+ *    then also delete it in the license file.
+ */
+
+#include <string>
+#include <vector>
+
+#include "mongo/base/status_with.h"
+#include "mongo/base/string_data.h"
+#include "mongo/unittest/unittest.h"
+#include "mongo/util/assert_util.h"
+
+namespace {
+
+    using mongo::StatusWith;
+
+    TEST(StatusWith, makeStatusWith) {
+        using mongo::makeStatusWith;
+        using mongo::StringData;
+
+        auto s1 = makeStatusWith<int>(3);
+        ASSERT_TRUE(s1.isOK());
+        ASSERT_EQUALS(uassertStatusOK(s1), 3);
+
+        auto s2 = makeStatusWith<std::vector<int>>();
+        ASSERT_TRUE(s2.isOK());
+        ASSERT_EQUALS(uassertStatusOK(s2).size(), 0u);
+
+        std::vector<int> i = {1, 2, 3};
+        auto s3 = makeStatusWith<std::vector<int>>(i.begin(), i.end());
+        ASSERT_TRUE(s3.isOK());
+        ASSERT_EQUALS(uassertStatusOK(s3).size(), 3u);
+
+        auto s4 = makeStatusWith<std::string>("foo");
+
+        ASSERT_TRUE(s4.isOK());
+        ASSERT_EQUALS(uassertStatusOK(s4), std::string{"foo"});
+        const char* foo = "barbaz";
+        auto s5 = makeStatusWith<StringData>(foo, std::size_t{6});
+        ASSERT_TRUE(s5.isOK());
+
+        // make sure CV qualifiers trigger correct overload
+        const StatusWith<StringData>& s6 = s5;
+        ASSERT_EQUALS(uassertStatusOK(s6), foo);
+        StatusWith<StringData>& s7 = s5;
+        ASSERT_EQUALS(uassertStatusOK(s7), foo);
+        ASSERT_EQUALS(uassertStatusOK(std::move(s5)), foo);
+
+        // Check that we use T(...) and not T{...}
+        // ASSERT_EQUALS requires an ostream overload for vector<int>
+        ASSERT_TRUE(makeStatusWith<std::vector<int>>(1, 2) == std::vector<int>{2});
+    }
+
+}  // namespace

src/mongo/util/assert_util.h

@@ -241,6 +241,16 @@ namespace mongo {
         }
     }
 
+    template<typename T>
+    MONGO_CLIENT_API inline T uassertStatusOK(StatusWith<T> sw) {
+        if (MONGO_unlikely(!sw.isOK())) {
+            const auto& status = sw.getStatus();
+            uasserted((status.location() != 0 ? status.location() : status.code()),
+                      status.reason());
+        }
+        return std::move(sw.getValue());
+    }
+
     /* warning only - keeps going */
 #define MONGO_wassert(_Expression) do {                                 \
         if (MONGO_unlikely(!(_Expression))) {                               \