// Copyright 2014 the V8 project authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include <limits>

#include "src/flags/flags.h"
#include "src/heap/memory-reducer.h"
#include "testing/gtest/include/gtest/gtest.h"

namespace v8 {
namespace internal {

MemoryReducer::Event MarkCompactEvent(double time_ms,
                                      bool next_gc_likely_to_collect_more,
                                      size_t committed_memory) {
  MemoryReducer::Event event;
  event.type = MemoryReducer::kMarkCompact;
  event.time_ms = time_ms;
  event.next_gc_likely_to_collect_more = next_gc_likely_to_collect_more;
  event.committed_memory = committed_memory;
  return event;
}

MemoryReducer::Event MarkCompactEventGarbageLeft(double time_ms,
                                                 size_t committed_memory) {
  return MarkCompactEvent(time_ms, true, committed_memory);
}

MemoryReducer::Event MarkCompactEventNoGarbageLeft(double time_ms,
                                                   size_t committed_memory) {
  return MarkCompactEvent(time_ms, false, committed_memory);
}


MemoryReducer::Event TimerEvent(double time_ms,
                                bool should_start_incremental_gc,
                                bool can_start_incremental_gc) {
  MemoryReducer::Event event;
  event.type = MemoryReducer::kTimer;
  event.time_ms = time_ms;
  event.should_start_incremental_gc = should_start_incremental_gc;
  event.can_start_incremental_gc = can_start_incremental_gc;
  return event;
}

int MaxNumberMemoryReducerGCs() {
  return v8_flags.memory_reducer_single_gc ? 1 : MemoryReducer::kMaxNumberOfGCs;
}

MemoryReducer::Event TimerEventLowAllocationRate(double time_ms) {
  return TimerEvent(time_ms, true, true);
}


MemoryReducer::Event TimerEventHighAllocationRate(double time_ms) {
  return TimerEvent(time_ms, false, true);
}


MemoryReducer::Event TimerEventPendingGC(double time_ms) {
  return TimerEvent(time_ms, true, false);
}

MemoryReducer::Event PossibleGarbageEvent(double time_ms) {
  MemoryReducer::Event event;
  event.type = MemoryReducer::kPossibleGarbage;
  event.time_ms = time_ms;
  return event;
}


TEST(MemoryReducer, FromDoneToDone) {
  MemoryReducer::State state0(MemoryReducer::State::CreateDone(1.0, 0)),
      state1(MemoryReducer::State::CreateDone(1.0, 0));

  state1 = MemoryReducer::Step(state0, TimerEventLowAllocationRate(0));
  EXPECT_EQ(MemoryReducer::kDone, state1.id());

  state1 = MemoryReducer::Step(state0, TimerEventHighAllocationRate(0));
  EXPECT_EQ(MemoryReducer::kDone, state1.id());

  state1 = MemoryReducer::Step(state0, TimerEventPendingGC(0));
  EXPECT_EQ(MemoryReducer::kDone, state1.id());

  state1 = MemoryReducer::Step(
      state0,
      MarkCompactEventGarbageLeft(0, MemoryReducer::kCommittedMemoryDelta - 1));
  EXPECT_EQ(MemoryReducer::kDone, state1.id());

  state0 = MemoryReducer::State::CreateDone(1, 1000 * MB);
  state1 = MemoryReducer::Step(
      state0, MarkCompactEventGarbageLeft(
                  0, static_cast<size_t>(
                         1000 * MB * MemoryReducer::kCommittedMemoryFactor) -
                         1));
  EXPECT_EQ(MemoryReducer::kDone, state1.id());
}


TEST(MemoryReducer, FromDoneToWait) {
  if (!v8_flags.incremental_marking) return;

  MemoryReducer::State state0(MemoryReducer::State::CreateDone(1.0, 0)),
      state1(MemoryReducer::State::CreateDone(1.0, 0));

  state1 = MemoryReducer::Step(
      state0,
      MarkCompactEventGarbageLeft(2, MemoryReducer::kCommittedMemoryDelta));
  EXPECT_EQ(MemoryReducer::kWait, state1.id());
  EXPECT_EQ(v8_flags.gc_memory_reducer_start_delay_ms + 2,
            state1.next_gc_start_ms());
  EXPECT_EQ(0, state1.started_gcs());
  EXPECT_EQ(2, state1.last_gc_time_ms());

  state1 = MemoryReducer::Step(
      state0,
      MarkCompactEventNoGarbageLeft(2, MemoryReducer::kCommittedMemoryDelta));
  EXPECT_EQ(MemoryReducer::kWait, state1.id());
  EXPECT_EQ(v8_flags.gc_memory_reducer_start_delay_ms + 2,
            state1.next_gc_start_ms());
  EXPECT_EQ(0, state1.started_gcs());
  EXPECT_EQ(2, state1.last_gc_time_ms());

  state1 = MemoryReducer::Step(state0, PossibleGarbageEvent(0));
  EXPECT_EQ(MemoryReducer::kWait, state1.id());
  EXPECT_EQ(v8_flags.gc_memory_reducer_start_delay_ms,
            state1.next_gc_start_ms());
  EXPECT_EQ(0, state1.started_gcs());
  EXPECT_EQ(state0.last_gc_time_ms(), state1.last_gc_time_ms());

  state0 = MemoryReducer::State::CreateDone(1, 1000 * MB);
  state1 = MemoryReducer::Step(
      state0, MarkCompactEventGarbageLeft(
                  2, static_cast<size_t>(
                         1000 * MB * MemoryReducer::kCommittedMemoryFactor)));
  EXPECT_EQ(MemoryReducer::kWait, state1.id());
  EXPECT_EQ(v8_flags.gc_memory_reducer_start_delay_ms + 2,
            state1.next_gc_start_ms());
  EXPECT_EQ(0, state1.started_gcs());
  EXPECT_EQ(2, state1.last_gc_time_ms());
}


TEST(MemoryReducer, FromWaitToWait) {
  if (!v8_flags.incremental_marking) return;

  MemoryReducer::State state0(MemoryReducer::State::CreateWait(
      MaxNumberMemoryReducerGCs() - 1, 1000.0, 1)),
      state1(MemoryReducer::State::CreateDone(1.0, 0));

  state1 = MemoryReducer::Step(state0, PossibleGarbageEvent(2000));
  EXPECT_EQ(MemoryReducer::kWait, state1.id());
  EXPECT_EQ(state0.next_gc_start_ms(), state1.next_gc_start_ms());
  EXPECT_EQ(state0.started_gcs(), state1.started_gcs());

  state1 = MemoryReducer::Step(
      state0, TimerEventLowAllocationRate(state0.next_gc_start_ms() - 1));
  EXPECT_EQ(MemoryReducer::kWait, state1.id());
  EXPECT_EQ(state0.next_gc_start_ms(), state1.next_gc_start_ms());
  EXPECT_EQ(state0.started_gcs(), state1.started_gcs());

  state1 = MemoryReducer::Step(state0, TimerEventHighAllocationRate(2000));
  EXPECT_EQ(MemoryReducer::kWait, state1.id());
  EXPECT_EQ(2000 + MemoryReducer::kLongDelayMs, state1.next_gc_start_ms());
  EXPECT_EQ(state0.started_gcs(), state1.started_gcs());

  state1 = MemoryReducer::Step(state0, TimerEventPendingGC(2000));
  EXPECT_EQ(MemoryReducer::kWait, state1.id());
  EXPECT_EQ(2000 + MemoryReducer::kLongDelayMs, state1.next_gc_start_ms());
  EXPECT_EQ(state0.started_gcs(), state1.started_gcs());

  state1 = MemoryReducer::Step(state0, MarkCompactEventGarbageLeft(2000, 0));
  EXPECT_EQ(MemoryReducer::kWait, state1.id());
  EXPECT_EQ(2000 + MemoryReducer::kLongDelayMs, state1.next_gc_start_ms());
  EXPECT_EQ(state0.started_gcs(), state1.started_gcs());
  EXPECT_EQ(2000, state1.last_gc_time_ms());

  state1 = MemoryReducer::Step(state0, MarkCompactEventNoGarbageLeft(2000, 0));
  EXPECT_EQ(MemoryReducer::kWait, state1.id());
  EXPECT_EQ(2000 + MemoryReducer::kLongDelayMs, state1.next_gc_start_ms());
  EXPECT_EQ(state0.started_gcs(), state1.started_gcs());
  EXPECT_EQ(2000, state1.last_gc_time_ms());

  state0 = MemoryReducer::State::CreateWait(MaxNumberMemoryReducerGCs() - 1,
                                            1000.0, 0);

  state1 = MemoryReducer::Step(
      state0,
      TimerEventHighAllocationRate(MemoryReducer::kWatchdogDelayMs + 1));
  EXPECT_EQ(MemoryReducer::kWait, state1.id());
  EXPECT_EQ(MemoryReducer::kWatchdogDelayMs + 1 + MemoryReducer::kLongDelayMs,
            state1.next_gc_start_ms());
  EXPECT_EQ(state0.started_gcs(), state1.started_gcs());
  EXPECT_EQ(state0.last_gc_time_ms(), state1.last_gc_time_ms());

  state0 = MemoryReducer::State::CreateWait(MaxNumberMemoryReducerGCs() - 1,
                                            1000.0, 1);
  state1 = MemoryReducer::Step(state0, TimerEventHighAllocationRate(2000));
  EXPECT_EQ(MemoryReducer::kWait, state1.id());
  EXPECT_EQ(2000 + MemoryReducer::kLongDelayMs, state1.next_gc_start_ms());
  EXPECT_EQ(state0.started_gcs(), state1.started_gcs());
  EXPECT_EQ(state0.last_gc_time_ms(), state1.last_gc_time_ms());
}


TEST(MemoryReducer, FromWaitToRun) {
  if (!v8_flags.incremental_marking) return;

  MemoryReducer::State state0(MemoryReducer::State::CreateWait(0, 1000.0, 1)),
      state1(MemoryReducer::State::CreateDone(1.0, 0));

  state1 = MemoryReducer::Step(
      state0, TimerEventLowAllocationRate(state0.next_gc_start_ms() + 1));
  EXPECT_EQ(MemoryReducer::kRun, state1.id());
  EXPECT_EQ(state0.started_gcs() + 1, state1.started_gcs());

  state1 = MemoryReducer::Step(
      state0,
      TimerEventHighAllocationRate(MemoryReducer::kWatchdogDelayMs + 2));
  EXPECT_EQ(MemoryReducer::kRun, state1.id());
  EXPECT_EQ(state0.started_gcs() + 1, state1.started_gcs());
}


TEST(MemoryReducer, FromWaitToDone) {
  if (!v8_flags.incremental_marking) return;
  if (v8_flags.memory_reducer_single_gc) return;

  MemoryReducer::State state0(
      MemoryReducer::State::CreateWait(MemoryReducer::kMaxNumberOfGCs, 0.0, 1)),
      state1(MemoryReducer::State::CreateDone(1.0, 0));

  state1 = MemoryReducer::Step(state0, TimerEventLowAllocationRate(2000));
  EXPECT_EQ(MemoryReducer::kDone, state1.id());
  EXPECT_EQ(MemoryReducer::kMaxNumberOfGCs, state1.started_gcs());
  EXPECT_EQ(state0.last_gc_time_ms(), state1.last_gc_time_ms());

  state1 = MemoryReducer::Step(state0, TimerEventHighAllocationRate(2000));
  EXPECT_EQ(MemoryReducer::kDone, state1.id());
  EXPECT_EQ(MemoryReducer::kMaxNumberOfGCs, state1.started_gcs());
  EXPECT_EQ(state0.last_gc_time_ms(), state1.last_gc_time_ms());

  state1 = MemoryReducer::Step(state0, TimerEventPendingGC(2000));
  EXPECT_EQ(MemoryReducer::kDone, state1.id());
  EXPECT_EQ(MemoryReducer::kMaxNumberOfGCs, state1.started_gcs());
  EXPECT_EQ(state0.last_gc_time_ms(), state1.last_gc_time_ms());
}


TEST(MemoryReducer, FromRunToRun) {
  if (!v8_flags.incremental_marking) return;

  MemoryReducer::State state0(MemoryReducer::State::CreateRun(1)),
      state1(MemoryReducer::State::CreateDone(1.0, 0));

  state1 = MemoryReducer::Step(state0, TimerEventLowAllocationRate(2000));
  EXPECT_EQ(MemoryReducer::kRun, state1.id());
  EXPECT_EQ(state0.started_gcs(), state1.started_gcs());

  state1 = MemoryReducer::Step(state0, TimerEventHighAllocationRate(2000));
  EXPECT_EQ(MemoryReducer::kRun, state1.id());
  EXPECT_EQ(state0.started_gcs(), state1.started_gcs());

  state1 = MemoryReducer::Step(state0, TimerEventPendingGC(2000));
  EXPECT_EQ(MemoryReducer::kRun, state1.id());
  EXPECT_EQ(state0.started_gcs(), state1.started_gcs());

  state1 = MemoryReducer::Step(state0, PossibleGarbageEvent(2000));
  EXPECT_EQ(MemoryReducer::kRun, state1.id());
  EXPECT_EQ(state0.started_gcs(), state1.started_gcs());
}


TEST(MemoryReducer, FromRunToDone) {
  if (!v8_flags.incremental_marking) return;

  const int started_gcs = v8_flags.memory_reducer_single_gc ? 1 : 2;
  MemoryReducer::State state0(MemoryReducer::State::CreateRun(started_gcs));
  MemoryReducer::State state1 =
      MemoryReducer::Step(state0, MarkCompactEventNoGarbageLeft(2000, 0));
  EXPECT_EQ(MemoryReducer::kDone, state1.id());
  EXPECT_EQ(MemoryReducer::kMaxNumberOfGCs, state1.started_gcs());
  EXPECT_EQ(2000, state1.last_gc_time_ms());

  state0 = MemoryReducer::State::CreateRun(MaxNumberMemoryReducerGCs());

  state1 = MemoryReducer::Step(state0, MarkCompactEventGarbageLeft(2000, 0));
  EXPECT_EQ(MemoryReducer::kDone, state1.id());
  EXPECT_EQ(state1.started_gcs(), state1.started_gcs());
}


TEST(MemoryReducer, FromRunToWait) {
  if (!v8_flags.incremental_marking) return;
  if (v8_flags.memory_reducer_single_gc) return;

  MemoryReducer::State state0(MemoryReducer::State::CreateRun(2)),
      state1(MemoryReducer::State::CreateDone(1.0, 0));

  state1 = MemoryReducer::Step(state0, MarkCompactEventGarbageLeft(2000, 0));
  EXPECT_EQ(MemoryReducer::kWait, state1.id());
  EXPECT_EQ(2000 + MemoryReducer::kShortDelayMs, state1.next_gc_start_ms());
  EXPECT_EQ(state0.started_gcs(), state1.started_gcs());
  EXPECT_EQ(2000, state1.last_gc_time_ms());

  state0 = MemoryReducer::State::CreateRun(1);

  state1 = MemoryReducer::Step(state0, MarkCompactEventNoGarbageLeft(2000, 0));
  EXPECT_EQ(MemoryReducer::kWait, state1.id());
  EXPECT_EQ(2000 + MemoryReducer::kShortDelayMs, state1.next_gc_start_ms());
  EXPECT_EQ(state0.started_gcs(), state1.started_gcs());
  EXPECT_EQ(2000, state1.last_gc_time_ms());
}

}  // namespace internal
}  // namespace v8