refactor: make clock decoupled from rdsn runtime (#398)

include/dsn/c/api_layer1.h

@@ -276,15 +276,6 @@ typedef struct
     int size;
 } dsn_file_buffer_t;
 
-/*!
-@defgroup env Environment
-
-Non-deterministic Environment Input
-
-Note developers can easily plugin their own implementation to
-replace the underneath implementation of these primitives.
-@{
-*/
 extern DSN_API uint64_t dsn_now_ns();
 
 __inline uint64_t dsn_now_us() { return dsn_now_ns() / 1000; }

include/dsn/tool-api/env_provider.h

@@ -57,8 +57,6 @@ class env_provider
     typedef env_provider *(*factory)(env_provider *);
 
     env_provider(env_provider *inner_provider);
-
-    DSN_API virtual uint64_t now_ns() const;
 };
 /*@}*/
 } // end namespace

include/dsn/utility/clock.h

@@ -0,0 +1,32 @@
+// Copyright (c) 2017, Xiaomi, Inc.  All rights reserved.
+// This source code is licensed under the Apache License Version 2.0, which
+// can be found in the LICENSE file in the root directory of this source tree.
+
+#pragma once
+
+#include <memory>
+
+namespace dsn {
+namespace utils {
+
+class clock
+{
+public:
+    clock() = default;
+    virtual ~clock() = default;
+
+    // Gets current time in nanoseconds.
+    virtual uint64_t now_ns() const;
+
+    // Gets singleton instance. eager singleton, which is thread safe
+    static const clock *instance();
+
+    // Resets the global clock implementation (not thread-safety)
+    static void mock(clock *mock_clock);
+
+private:
+    static std::unique_ptr<clock> _clock;
+};
+
+} // namespace utils
+} // namespace dsn

src/core/core/clock.cpp

@@ -0,0 +1,24 @@
+// Copyright (c) 2017, Xiaomi, Inc.  All rights reserved.
+// This source code is licensed under the Apache License Version 2.0, which
+// can be found in the LICENSE file in the root directory of this source tree.
+
+#include <dsn/utility/clock.h>
+#include <dsn/utility/time_utils.h>
+#include <dsn/utility/dlib.h>
+#include <dsn/utility/smart_pointers.h>
+
+DSN_API uint64_t dsn_now_ns() { return dsn::utils::clock::instance()->now_ns(); }
+
+namespace dsn {
+namespace utils {
+
+std::unique_ptr<clock> clock::_clock = make_unique<clock>();
+
+const clock *clock::instance() { return _clock.get(); }
+
+uint64_t clock::now_ns() const { return get_current_physical_time_ns(); }
+
+void clock::mock(clock *mock_clock) { _clock.reset(mock_clock); }
+
+} // namespace utils
+} // namespace dsn

src/core/core/env_provider.cpp

@@ -45,6 +45,4 @@ namespace dsn {
 
 env_provider::env_provider(env_provider *inner_provider) {}
 
-uint64_t env_provider::now_ns() const { return utils::get_current_physical_time_ns(); }
-
 } // end namespace

src/core/core/service_api_c.cpp

@@ -151,17 +151,6 @@ DSN_API void dsn_rpc_forward(dsn::message_ex *request, dsn::rpc_address addr)
                                             ::dsn::rpc_address(addr));
 }
 
-//------------------------------------------------------------------------------
-//
-// env
-//
-//------------------------------------------------------------------------------
-DSN_API uint64_t dsn_now_ns()
-{
-    // return ::dsn::task::get_current_env()->now_ns();
-    return ::dsn::service_engine::instance().env()->now_ns();
-}
-
 //------------------------------------------------------------------------------
 //
 // system

src/core/tools/simulator/env.sim.cpp

@@ -43,8 +43,6 @@ namespace tools {
 
 /*static*/ int sim_env_provider::_seed;
 
-uint64_t sim_env_provider::now_ns() const { return scheduler::instance().now_ns(); }
-
 void sim_env_provider::on_worker_start(task_worker *worker)
 {
     rand::reseed_thread_local_rng(

src/core/tools/simulator/env.sim.h

@@ -44,9 +44,6 @@ class sim_env_provider : public env_provider
 {
 public:
     sim_env_provider(env_provider *inner_provider);
-
-    // service local time (can be logical or physical)
-    virtual uint64_t now_ns() const override;
     static int seed() { return _seed; }
 
 private:

src/core/tools/simulator/sim_clock.h

@@ -0,0 +1,24 @@
+// Copyright (c) 2017, Xiaomi, Inc.  All rights reserved.
+// This source code is licensed under the Apache License Version 2.0, which
+// can be found in the LICENSE file in the root directory of this source tree.
+
+#pragma once
+
+#include <dsn/utility/clock.h>
+#include "scheduler.h"
+
+namespace dsn {
+namespace tools {
+
+class sim_clock : public utils::clock
+{
+public:
+    sim_clock() = default;
+    virtual ~sim_clock() = default;
+
+    // Gets simulated time in nanoseconds.
+    virtual uint64_t now_ns() const { return scheduler::instance().now_ns(); }
+};
+
+} // namespace tools
+} // namespace dsn

src/core/tools/simulator/simulator.cpp

@@ -39,6 +39,7 @@
 #include "diske.sim.h"
 #include "env.sim.h"
 #include "task_engine.sim.h"
+#include "sim_clock.h"
 
 namespace dsn {
 namespace tools {
@@ -118,6 +119,9 @@ void simulator::install(service_spec &spec)
     }
 
     sys_exit.put_front(simulator::on_system_exit, "simulator");
+
+    // the new sim_clock is taken over by unique_ptr in clock instance
+    utils::clock::instance()->mock(new sim_clock());
 }
 
 void simulator::on_system_exit(sys_exit_type st)
@@ -131,5 +135,5 @@ void simulator::run()
     scheduler::instance().start();
     tool_app::run();
 }
-}
-} // end namespace dsn::tools
+} // namespace tools
+} // namespace dsn