SERVER-44047 Add timer support to Interruptible::waitForConditionOrInterrupt()

1 files changed, 126 insertions, 0 deletions

diff --git a/src/mongo/util/interruptible_test.cpp b/src/mongo/util/interruptible_test.cpp
new file mode 100644
index 00000000000..32b5ba80ac0
--- /dev/null
+++ b/src/mongo/util/interruptible_test.cpp
@@ -0,0 +1,126 @@
+/**
+ *    Copyright (C) 2018-present MongoDB, Inc.
+ *
+ *    This program is free software: you can redistribute it and/or modify
+ *    it under the terms of the Server Side Public License, version 1,
+ *    as published by MongoDB, Inc.
+ *
+ *    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
+ *    Server Side Public License for more details.
+ *
+ *    You should have received a copy of the Server Side Public License
+ *    along with this program. If not, see
+ *    <http://www.mongodb.com/licensing/server-side-public-license>.
+ *
+ *    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 Server Side 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/stdx/thread.h"
+#include "mongo/unittest/unittest.h"
+#include "mongo/util/interruptible.h"
+#include "mongo/util/time_support.h"
+
+namespace mongo {
+namespace {
+
+class DummyInterruptable final : public Interruptible {
+    Date_t getDeadline() const override {
+        MONGO_UNREACHABLE;
+    }
+    Status checkForInterruptNoAssert() noexcept override {
+        MONGO_UNREACHABLE;
+    }
+    IgnoreInterruptsState pushIgnoreInterrupts() override {
+        MONGO_UNREACHABLE;
+    }
+    void popIgnoreInterrupts(IgnoreInterruptsState iis) override {
+        MONGO_UNREACHABLE;
+    }
+    DeadlineState pushArtificialDeadline(Date_t deadline, ErrorCodes::Error error) override {
+        MONGO_UNREACHABLE;
+    }
+    void popArtificialDeadline(DeadlineState) override {
+        MONGO_UNREACHABLE;
+    }
+    Date_t getExpirationDateForWaitForValue(Milliseconds waitFor) override {
+        return Date_t::now() + waitFor;
+    }
+    StatusWith<stdx::cv_status> waitForConditionOrInterruptNoAssertUntil(
+        stdx::condition_variable& cv, BasicLockableAdapter m, Date_t deadline) noexcept override {
+        while (Date_t::now() < deadline) {
+            sleepmillis(duration_cast<Milliseconds>(precision).count());
+        }
+        return stdx::cv_status::timeout;
+    }
+
+public:
+    const Milliseconds precision = Milliseconds(5);
+};
+
+TEST(Interruptible, WaitForConditionOrInterruptTimed) {
+    auto interruptible = std::make_unique<DummyInterruptable>();
+    const auto sleepFor = Milliseconds(500);
+
+    auto mutex = MONGO_MAKE_LATCH();
+    stdx::condition_variable cv;
+    stdx::unique_lock<Latch> lk(mutex);
+    AtomicWord<Microseconds::rep> waitTimer(0);
+
+    const auto start = Date_t::now();
+    Date_t deadline = Date_t::now() + sleepFor;
+    interruptible->waitForConditionOrInterruptUntil(cv,
+                                                    lk,
+                                                    deadline,
+                                                    [&, oldWaitTimer = 0]() mutable {
+                                                        /**
+                                                         * Make sure it never resets the waitTimer.
+                                                         * waitTimer should always monotonically
+                                                         * increase.
+                                                         */
+                                                        ASSERT_GTE(waitTimer.load(), oldWaitTimer);
+                                                        oldWaitTimer = waitTimer.load();
+                                                        return false;
+                                                    },
+                                                    &waitTimer);
+    const auto end = Date_t::now();
+
+    const auto duration = duration_cast<Milliseconds>(end - start);
+    ASSERT_GTE(duration + interruptible->precision, sleepFor);
+    /**
+     * The following assumes the testing environment is not heavily contended.
+     * So long as the OS scheduler does not take more than 5~ms to reschedule
+     * this thread, the following assertion should pass.
+     */
+    ASSERT_LTE(duration_cast<Microseconds>(sleepFor).count(),
+               waitTimer.load() + duration_cast<Microseconds>(interruptible->precision).count());
+    ASSERT_FALSE(interruptible->isWaitingForConditionOrInterrupt());
+}
+
+TEST(Interruptible, ZeroWaitTimeForImmediateReturn) {
+    auto interruptible = std::make_unique<DummyInterruptable>();
+    auto mutex = MONGO_MAKE_LATCH();
+    stdx::condition_variable cv;
+    stdx::unique_lock<Latch> lk(mutex);
+    AtomicWord<Microseconds::rep> waitTimer(0);
+    Date_t deadline = Date_t::now() + Milliseconds(100);
+
+    interruptible->waitForConditionOrInterruptUntil(
+        cv, lk, deadline, [&]() { return true; }, &waitTimer);
+    ASSERT_EQ(waitTimer.load(), 0);
+}
+
+}  // namespace
+}  // namespace mongo