SERVER-18774 Add ClockSource interface

6 files changed, 260 insertions, 0 deletions

diff --git a/src/mongo/util/SConscript b/src/mongo/util/SConscript
index bb0528e6077..b932c45a325 100644
--- a/src/mongo/util/SConscript
+++ b/src/mongo/util/SConscript
@@ -124,6 +124,13 @@ env.Library(
     ],
 )
 
+env.Library(
+    target='clock_source_mock',
+    source=[
+        'clock_source_mock.cpp',
+    ],
+)
+
 env.CppUnitTest(
     target='text_test',
     source=[
diff --git a/src/mongo/util/clock_source.h b/src/mongo/util/clock_source.h
new file mode 100644
index 00000000000..6ba47e6fce3
--- /dev/null
+++ b/src/mongo/util/clock_source.h
@@ -0,0 +1,48 @@
+/**
+ *    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.
+ */
+
+#pragma once
+
+namespace mongo {
+
+class Date_t;
+
+/**
+ * An interface for getting the current wall clock time.
+ */
+class ClockSource {
+public:
+    virtual ~ClockSource() = default;
+
+    /**
+     * Returns the current wall clock time, as defined by this source.
+     */
+    virtual Date_t now() = 0;
+};
+
+}  // namespace mongo
diff --git a/src/mongo/util/clock_source_mock.cpp b/src/mongo/util/clock_source_mock.cpp
new file mode 100644
index 00000000000..ba5c9cef2e3
--- /dev/null
+++ b/src/mongo/util/clock_source_mock.cpp
@@ -0,0 +1,48 @@
+/**
+ *    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 "mongo/platform/basic.h"
+
+#include "mongo/util/clock_source_mock.h"
+
+namespace mongo {
+
+ClockSourceMock::ClockSourceMock(Date_t now) : _now(now) {}
+
+Date_t ClockSourceMock::now() {
+    return _now;
+}
+
+void ClockSourceMock::advance(stdx::chrono::milliseconds ms) {
+    _now += ms;
+}
+
+void ClockSourceMock::reset(Date_t newNow) {
+    _now = newNow;
+}
+}  // namespace mongo
diff --git a/src/mongo/util/clock_source_mock.h b/src/mongo/util/clock_source_mock.h
new file mode 100644
index 00000000000..2f53abc23b6
--- /dev/null
+++ b/src/mongo/util/clock_source_mock.h
@@ -0,0 +1,62 @@
+/**
+ *    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.
+ */
+
+#pragma once
+
+#include "mongo/util/clock_source.h"
+#include "mongo/util/time_support.h"
+
+namespace mongo {
+
+/**
+ * Mock clock source that returns a fixed time until explicitly advanced.
+ */
+class ClockSourceMock final : public ClockSource {
+public:
+    /**
+     * Constructs a ClockSourceMock with the current time initialized to the given value.
+     */
+    explicit ClockSourceMock(Date_t now);
+
+    Date_t now() final;
+
+    /**
+     * Advances the current time by the given value.
+     */
+    void advance(stdx::chrono::milliseconds ms);
+
+    /**
+     * Resets the current time to the given value.
+     */
+    void reset(Date_t newNow);
+
+private:
+    Date_t _now;
+};
+
+}  // namespace mongo
diff --git a/src/mongo/util/system_clock_source.cpp b/src/mongo/util/system_clock_source.cpp
new file mode 100644
index 00000000000..ac64e49ca62
--- /dev/null
+++ b/src/mongo/util/system_clock_source.cpp
@@ -0,0 +1,47 @@
+/**
+ *    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 "mongo/platform/basic.h"
+
+#include "mongo/util/system_clock_source.h"
+
+#include "mongo/stdx/memory.h"
+#include "mongo/util/time_support.h"
+
+namespace mongo {
+
+Date_t SystemClockSource::now() {
+    return Date_t::now();
+}
+
+SystemClockSource* SystemClockSource::get() {
+    static const auto globalSystemClockSource = stdx::make_unique<SystemClockSource>();
+    return globalSystemClockSource.get();
+}
+
+}  // namespace mongo
diff --git a/src/mongo/util/system_clock_source.h b/src/mongo/util/system_clock_source.h
new file mode 100644
index 00000000000..69f2b661d86
--- /dev/null
+++ b/src/mongo/util/system_clock_source.h
@@ -0,0 +1,48 @@
+/**
+ *    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.
+ */
+
+#pragma once
+
+#include "mongo/util/clock_source.h"
+
+namespace mongo {
+
+/**
+ * Clock source based on the system clock.
+ */
+class SystemClockSource final : public ClockSource {
+public:
+    Date_t now() final;
+
+    /**
+     * Returns the singleton instance of SystemClockSource.
+     */
+    static SystemClockSource* get();
+};
+
+}  // namespace mongo