message_queue.cc 2.9 KB

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  1. // Copyright 2016 The Chromium Authors. All rights reserved.
  2. // Use of this source code is governed by a BSD-style license that can be
  3. // found in the LICENSE file.
  4. #include "mojo/core/ports/message_queue.h"
  5. #include <algorithm>
  6. #include "base/compiler_specific.h"
  7. #include "base/logging.h"
  8. #include "mojo/core/ports/message_filter.h"
  9. namespace mojo {
  10. namespace core {
  11. namespace ports {
  12. // Used by std::{push,pop}_heap functions
  13. inline bool operator<(const std::unique_ptr<UserMessageEvent>& a,
  14. const std::unique_ptr<UserMessageEvent>& b) {
  15. return a->sequence_num() > b->sequence_num();
  16. }
  17. MessageQueue::MessageQueue() : MessageQueue(kInitialSequenceNum) {}
  18. MessageQueue::MessageQueue(uint64_t next_sequence_num)
  19. : next_sequence_num_(next_sequence_num) {
  20. // The message queue is blocked waiting for a message with sequence number
  21. // equal to |next_sequence_num|.
  22. }
  23. MessageQueue::~MessageQueue() {
  24. #if DCHECK_IS_ON()
  25. size_t num_leaked_ports = 0;
  26. for (const auto& message : heap_)
  27. num_leaked_ports += message->num_ports();
  28. DVLOG_IF(1, num_leaked_ports > 0)
  29. << "Leaking " << num_leaked_ports << " ports in unreceived messages";
  30. #endif
  31. }
  32. bool MessageQueue::HasNextMessage() const {
  33. return !heap_.empty() && heap_[0]->sequence_num() == next_sequence_num_;
  34. }
  35. void MessageQueue::GetNextMessage(std::unique_ptr<UserMessageEvent>* message,
  36. MessageFilter* filter) {
  37. if (!HasNextMessage() || (filter && !filter->Match(*heap_[0]))) {
  38. message->reset();
  39. return;
  40. }
  41. std::pop_heap(heap_.begin(), heap_.end());
  42. *message = std::move(heap_.back());
  43. total_queued_bytes_ -= (*message)->GetSizeIfSerialized();
  44. heap_.pop_back();
  45. // We keep the capacity of |heap_| in check so that a large batch of incoming
  46. // messages doesn't permanently wreck available memory. The choice of interval
  47. // here is somewhat arbitrary.
  48. constexpr size_t kHeapMinimumShrinkSize = 16;
  49. constexpr size_t kHeapShrinkInterval = 512;
  50. if (UNLIKELY(heap_.size() > kHeapMinimumShrinkSize &&
  51. heap_.size() % kHeapShrinkInterval == 0)) {
  52. heap_.shrink_to_fit();
  53. }
  54. }
  55. void MessageQueue::AcceptMessage(std::unique_ptr<UserMessageEvent> message,
  56. bool* has_next_message) {
  57. // TODO: Handle sequence number roll-over.
  58. total_queued_bytes_ += message->GetSizeIfSerialized();
  59. heap_.emplace_back(std::move(message));
  60. std::push_heap(heap_.begin(), heap_.end());
  61. if (!signalable_) {
  62. *has_next_message = false;
  63. } else {
  64. *has_next_message = (heap_[0]->sequence_num() == next_sequence_num_);
  65. }
  66. }
  67. void MessageQueue::TakeAllMessages(
  68. std::vector<std::unique_ptr<UserMessageEvent>>* messages) {
  69. *messages = std::move(heap_);
  70. total_queued_bytes_ = 0;
  71. }
  72. void MessageQueue::MessageProcessed() {
  73. next_sequence_num_++;
  74. }
  75. } // namespace ports
  76. } // namespace core
  77. } // namespace mojo