SERVER-18774 Add ClockSource interface

11 files changed, 280 insertions, 4 deletions

diff --git a/src/mongo/SConscript b/src/mongo/SConscript
index b67a9630633..bab71bd6ac8 100644
--- a/src/mongo/SConscript
+++ b/src/mongo/SConscript
@@ -102,6 +102,7 @@ baseSource=[
     'util/stacktrace.cpp',
     'util/static_observer.cpp',
     'util/stringutils.cpp',
+    'util/system_clock_source.cpp',
     'util/system_tick_source.cpp',
     'util/text.cpp',
     'util/time_support.cpp',
diff --git a/src/mongo/db/service_context.cpp b/src/mongo/db/service_context.cpp
index 8dfa7bfdc98..7fe0e237bdc 100644
--- a/src/mongo/db/service_context.cpp
+++ b/src/mongo/db/service_context.cpp
@@ -147,10 +147,18 @@ TickSource* ServiceContext::getTickSource() const {
     return _tickSource.get();
 }
 
+ClockSource* ServiceContext::getClockSource() const {
+    return _clockSource.get();
+}
+
 void ServiceContext::setTickSource(std::unique_ptr<TickSource> newSource) {
     _tickSource = std::move(newSource);
 }
 
+void ServiceContext::setClockSource(std::unique_ptr<ClockSource> newSource) {
+    _clockSource = std::move(newSource);
+}
+
 void ServiceContext::ClientDeleter::operator()(Client* client) const {
     ServiceContext* const service = client->getServiceContext();
     {
diff --git a/src/mongo/db/service_context.h b/src/mongo/db/service_context.h
index 8f07c34d5a1..6f9aa36a22f 100644
--- a/src/mongo/db/service_context.h
+++ b/src/mongo/db/service_context.h
@@ -36,6 +36,7 @@
 #include "mongo/platform/unordered_set.h"
 #include "mongo/stdx/functional.h"
 #include "mongo/util/decorable.h"
+#include "mongo/util/clock_source.h"
 #include "mongo/util/tick_source.h"
 
 namespace mongo {
@@ -308,16 +309,17 @@ public:
     virtual OpObserver* getOpObserver() = 0;
 
     /**
-     * Returns the tick source set in this context.
+     * Returns the tick/clock source set in this context.
      */
     TickSource* getTickSource() const;
+    ClockSource* getClockSource() const;
 
     /**
-     * Replaces the current tick source with a new one. In other words, the old tick source
-     * will be destroyed. So make sure that no one is using the old tick source when
-     * calling this.
+     * Replaces the current tick/clock source with a new one. In other words, the old source will be
+     * destroyed. So make sure that no one is using the old source when calling this.
      */
     void setTickSource(std::unique_ptr<TickSource> newSource);
+    void setClockSource(std::unique_ptr<ClockSource> newSource);
 
 protected:
     ServiceContext() = default;
@@ -341,6 +343,7 @@ private:
     ClientSet _clients;
 
     std::unique_ptr<TickSource> _tickSource;
+    std::unique_ptr<ClockSource> _clockSource;
 };
 
 /**
diff --git a/src/mongo/db/service_context_d.cpp b/src/mongo/db/service_context_d.cpp
index cef92203f59..af17b210db9 100644
--- a/src/mongo/db/service_context_d.cpp
+++ b/src/mongo/db/service_context_d.cpp
@@ -50,6 +50,7 @@
 #include "mongo/util/map_util.h"
 #include "mongo/util/mongoutils/str.h"
 #include "mongo/util/scopeguard.h"
+#include "mongo/util/system_clock_source.h"
 #include "mongo/util/system_tick_source.h"
 
 namespace mongo {
@@ -57,6 +58,7 @@ namespace mongo {
 MONGO_INITIALIZER(SetGlobalEnvironment)(InitializerContext* context) {
     setGlobalServiceContext(stdx::make_unique<ServiceContextMongoD>());
     getGlobalServiceContext()->setTickSource(stdx::make_unique<SystemTickSource>());
+    getGlobalServiceContext()->setClockSource(stdx::make_unique<SystemClockSource>());
     return Status::OK();
 }
 
diff --git a/src/mongo/s/server.cpp b/src/mongo/s/server.cpp
index a2c7cec3ff6..d74f4823aa7 100644
--- a/src/mongo/s/server.cpp
+++ b/src/mongo/s/server.cpp
@@ -85,6 +85,7 @@
 #include "mongo/util/stacktrace.h"
 #include "mongo/util/static_observer.h"
 #include "mongo/util/stringutils.h"
+#include "mongo/util/system_clock_source.h"
 #include "mongo/util/system_tick_source.h"
 #include "mongo/util/text.h"
 #include "mongo/util/version.h"
@@ -360,6 +361,7 @@ MONGO_INITIALIZER(CreateAuthorizationExternalStateFactory)(InitializerContext* c
 MONGO_INITIALIZER(SetGlobalEnvironment)(InitializerContext* context) {
     setGlobalServiceContext(stdx::make_unique<ServiceContextNoop>());
     getGlobalServiceContext()->setTickSource(stdx::make_unique<SystemTickSource>());
+    getGlobalServiceContext()->setClockSource(stdx::make_unique<SystemClockSource>());
     return Status::OK();
 }
 
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