dht: persist values with system time

include/opendht/utils.h

@@ -85,6 +85,14 @@ using system_clock = std::chrono::system_clock;
 using time_point = clock::time_point;
 using duration = clock::duration;
 
+OPENDHT_PUBLIC time_point from_system_time(system_clock::time_point t,
+                                           time_point steady_now,
+                                           system_clock::time_point system_now);
+OPENDHT_PUBLIC time_point from_system_time(system_clock::time_point t);
+OPENDHT_PUBLIC system_clock::time_point to_system_time(time_point t,
+                                                       time_point steady_now,
+                                                       system_clock::time_point system_now);
+OPENDHT_PUBLIC system_clock::time_point to_system_time(time_point t);
 OPENDHT_PUBLIC time_point from_time_t(std::time_t t);
 OPENDHT_PUBLIC std::time_t to_time_t(time_point t);
 

src/dht.cpp

@@ -2363,6 +2363,9 @@ Dht::confirmNodes()
 std::vector<ValuesExport>
 Dht::exportValues() const
 {
+    const auto& now = scheduler.time();
+    const auto system_now = system_clock::now();
+
     std::vector<ValuesExport> e {};
     e.reserve(store.size());
     for (const auto& h : store) {
@@ -2375,7 +2378,7 @@ Dht::exportValues() const
         pk.pack_array(vals.size());
         for (const auto& v : vals) {
             pk.pack_array(4);
-            pk.pack(v.created.time_since_epoch().count());
+            pk.pack(to_system_time(v.created, now, system_now));
             v.data->msgpack_pack(pk);
             if (const auto& store_addr = v.store_bucket ? v.store_bucket->getAddr() : SockAddr {}) {
                 pk.pack_bin(store_addr.getLength());
@@ -2383,7 +2386,7 @@ Dht::exportValues() const
             } else {
                 pk.pack_bin(0);
             }
-            pk.pack(v.expiration.time_since_epoch().count());
+            pk.pack(to_system_time(v.expiration, now, system_now));
         }
         ve.second = {buffer.data(), buffer.data() + buffer.size()};
         e.push_back(std::move(ve));
@@ -2395,6 +2398,7 @@ void
 Dht::importValues(const std::vector<ValuesExport>& import)
 {
     const auto& now = scheduler.time();
+    const auto system_now = system_clock::now();
 
     unsigned imported = 0, ignored = 0;
     size_t imported_size = 0;
@@ -2419,8 +2423,15 @@ Dht::importValues(const std::vector<ValuesExport>& import)
                 Value tmp_val;
                 SockAddr store_addr;
                 try {
-                    val_time = time_point {
-                        time_point::duration {valel.via.array.ptr[0].as<time_point::duration::rep>()}};
+                    const bool uses_system_time = valel.via.array.ptr[0].type == msgpack::type::EXT;
+                    if (uses_system_time) {
+                        val_time = from_system_time(valel.via.array.ptr[0].as<system_clock::time_point>(),
+                                                    now,
+                                                    system_now);
+                    } else {
+                        val_time = time_point {
+                            time_point::duration {valel.via.array.ptr[0].as<time_point::duration::rep>()}};
+                    }
                     tmp_val.msgpack_unpack(valel.via.array.ptr[1]);
                     if (valel.via.array.size >= 3) {
                         auto addr_blob = valel.via.array.ptr[2].as<Blob>();
@@ -2430,8 +2441,14 @@ Dht::importValues(const std::vector<ValuesExport>& import)
                         }
                     }
                     if (valel.via.array.size >= 4) {
-                        expiration = time_point {
-                            time_point::duration {valel.via.array.ptr[3].as<time_point::duration::rep>()}};
+                        if (uses_system_time) {
+                            expiration = from_system_time(valel.via.array.ptr[3].as<system_clock::time_point>(),
+                                                          now,
+                                                          system_now);
+                        } else {
+                            expiration = time_point {
+                                time_point::duration {valel.via.array.ptr[3].as<time_point::duration::rep>()}};
+                        }
                     }
                 } catch (const std::exception&) {
                     if (logger_)

src/utils.cpp

@@ -238,28 +238,58 @@ operator==(const SockAddr& a, const SockAddr& b)
     return a.equals(b);
 }
 
+time_point
+from_system_time(system_clock::time_point t, time_point steady_now, system_clock::time_point system_now)
+{
+    if (t == system_clock::time_point::min())
+        return time_point::min();
+    if (t == system_clock::time_point::max())
+        return time_point::max();
+    auto dt = t - system_now;
+    if (dt > system_clock::duration(0) and steady_now > time_point::max() - dt)
+        return time_point::max();
+    else if (dt < system_clock::duration(0) and steady_now < time_point::min() - dt)
+        return time_point::min();
+    return steady_now + dt;
+}
+
+time_point
+from_system_time(system_clock::time_point t)
+{
+    return from_system_time(t, clock::now(), system_clock::now());
+}
+
+system_clock::time_point
+to_system_time(time_point t, time_point steady_now, system_clock::time_point system_now)
+{
+    if (t == time_point::min())
+        return system_clock::time_point::min();
+    if (t == time_point::max())
+        return system_clock::time_point::max();
+    auto dt = t - steady_now;
+    if (dt > duration(0) and system_now >= system_clock::time_point::max() - dt)
+        return system_clock::time_point::max();
+    else if (dt < duration(0) and system_now <= system_clock::time_point::min() - dt)
+        return system_clock::time_point::min();
+    return system_now + std::chrono::duration_cast<system_clock::duration>(dt);
+}
+
+system_clock::time_point
+to_system_time(time_point t)
+{
+    return to_system_time(t, clock::now(), system_clock::now());
+}
+
 time_point
 from_time_t(std::time_t t)
 {
-    auto dt = system_clock::from_time_t(t) - system_clock::now();
-    auto now = clock::now();
-    if (dt > system_clock::duration(0) and now > time_point::max() - dt)
-        return time_point::max();
-    else if (dt < system_clock::duration(0) and now < time_point::min() - dt)
-        return time_point::min();
-    return now + dt;
+    return from_system_time(system_clock::from_time_t(t));
 }
 
 std::time_t
 to_time_t(time_point t)
 {
-    auto dt = t - clock::now();
-    auto now = system_clock::now();
-    if (dt > duration(0) and now >= system_clock::time_point::max() - dt)
-        return system_clock::to_time_t(system_clock::time_point::max());
-    else if (dt < duration(0) and now <= system_clock::time_point::min() - dt)
-        return system_clock::to_time_t(system_clock::time_point::min());
-    return system_clock::to_time_t(now + std::chrono::duration_cast<system_clock::duration>(dt));
+    return system_clock::to_time_t(to_system_time(t));
 }
 
 Blob

tests/test_dhtrunner.cpp

@@ -210,6 +210,42 @@ DhtRunnerTester::testImportValuesPreservesRemoteQuota()
     restored.join();
 }
 
+void
+DhtRunnerTester::testExportValuesUsesSystemTime()
+{
+    auto key = dht::InfoHash::get("export-system-time");
+    const auto created = dht::clock::now();
+    msgpack::sbuffer importBuffer;
+    msgpack::packer<msgpack::sbuffer> pk(&importBuffer);
+    pk.pack_array(1);
+    pk.pack_array(2);
+    pk.pack(created.time_since_epoch().count());
+    dht::Value {std::string("persisted")}.msgpack_pack(pk);
+    node1.importValues({
+        dht::ValuesExport {key, {importBuffer.data(), importBuffer.data() + importBuffer.size()}}
+    });
+
+    auto exported = node1.exportValues();
+    CPPUNIT_ASSERT_EQUAL(size_t(1), exported.size());
+
+    msgpack::unpacked msg;
+    msgpack::unpack(msg, reinterpret_cast<const char*>(exported.front().second.data()), exported.front().second.size());
+    const auto values = msg.get();
+    CPPUNIT_ASSERT(values.type == msgpack::type::ARRAY);
+    CPPUNIT_ASSERT_EQUAL(uint32_t(1), values.via.array.size);
+    const auto& persistedValue = values.via.array.ptr[0];
+    CPPUNIT_ASSERT_EQUAL(uint32_t(4), persistedValue.via.array.size);
+    CPPUNIT_ASSERT(persistedValue.via.array.ptr[0].type == msgpack::type::EXT);
+    CPPUNIT_ASSERT(persistedValue.via.array.ptr[3].type == msgpack::type::EXT);
+
+    const auto persistedCreated = persistedValue.via.array.ptr[0].as<std::chrono::system_clock::time_point>();
+    const auto persistedExpiration = persistedValue.via.array.ptr[3].as<std::chrono::system_clock::time_point>();
+    const auto delta = std::chrono::system_clock::now() - persistedCreated;
+    CPPUNIT_ASSERT(delta >= std::chrono::system_clock::duration::zero());
+    CPPUNIT_ASSERT(delta < 5s);
+    CPPUNIT_ASSERT(persistedExpiration > persistedCreated);
+}
+
 void
 DhtRunnerTester::testImportValuesPreservesStoredExpiration()
 {

tests/test_dhtrunner.h

@@ -21,6 +21,7 @@ class DhtRunnerTester : public CppUnit::TestFixture
     CPPUNIT_TEST(testListenLotOfBytes);
     CPPUNIT_TEST(testIdOps);
     CPPUNIT_TEST(testImportValuesPreservesRemoteQuota);
+    CPPUNIT_TEST(testExportValuesUsesSystemTime);
     CPPUNIT_TEST(testImportValuesPreservesStoredExpiration);
     CPPUNIT_TEST(testImportPermanentValueExpires);
     CPPUNIT_TEST(testBootstrapSetsConnectingState);
@@ -67,6 +68,7 @@ public:
      */
     void testIdOps();
     void testImportValuesPreservesRemoteQuota();
+    void testExportValuesUsesSystemTime();
     void testImportValuesPreservesStoredExpiration();
     void testImportPermanentValueExpires();
     void testBootstrapSetsConnectingState();