| // Copyright 2014 The Chromium Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #ifndef NET_THIRD_PARTY_QUIC_CORE_QUIC_WRITE_BLOCKED_LIST_H_ |
| #define NET_THIRD_PARTY_QUIC_CORE_QUIC_WRITE_BLOCKED_LIST_H_ |
| |
| #include <cstddef> |
| #include <cstdint> |
| |
| #include "base/macros.h" |
| #include "net/third_party/quic/core/quic_packets.h" |
| #include "net/third_party/quic/platform/api/quic_containers.h" |
| #include "net/third_party/quic/platform/api/quic_export.h" |
| #include "net/third_party/quic/platform/api/quic_map_util.h" |
| #include "net/third_party/quiche/src/spdy/core/priority_write_scheduler.h" |
| |
| namespace quic { |
| |
| // Keeps tracks of the QUIC streams that have data to write, sorted by |
| // priority. QUIC stream priority order is: |
| // Crypto stream > Headers stream > Data streams by requested priority. |
| class QUIC_EXPORT_PRIVATE QuicWriteBlockedList { |
| private: |
| typedef spdy::PriorityWriteScheduler<QuicStreamId> QuicPriorityWriteScheduler; |
| |
| public: |
| explicit QuicWriteBlockedList(); |
| QuicWriteBlockedList(const QuicWriteBlockedList&) = delete; |
| QuicWriteBlockedList& operator=(const QuicWriteBlockedList&) = delete; |
| ~QuicWriteBlockedList(); |
| |
| bool HasWriteBlockedDataStreams() const { |
| return priority_write_scheduler_.HasReadyStreams(); |
| } |
| |
| bool HasWriteBlockedSpecialStream() const { |
| return static_stream_collection_.num_blocked() > 0; |
| } |
| |
| size_t NumBlockedSpecialStreams() const { |
| return static_stream_collection_.num_blocked(); |
| } |
| |
| size_t NumBlockedStreams() const { |
| return NumBlockedSpecialStreams() + |
| priority_write_scheduler_.NumReadyStreams(); |
| } |
| |
| bool ShouldYield(QuicStreamId id) const { |
| for (const auto& stream : static_stream_collection_) { |
| if (stream.id == id) { |
| // Static streams should never yield to data streams, or to lower |
| // priority static stream. |
| return false; |
| } |
| if (stream.is_blocked) { |
| return true; // All data streams yield to static streams. |
| } |
| } |
| |
| return priority_write_scheduler_.ShouldYield(id); |
| } |
| |
| // Pops the highest priorty stream, special casing crypto and headers streams. |
| // Latches the most recently popped data stream for batch writing purposes. |
| QuicStreamId PopFront() { |
| QuicStreamId static_stream_id; |
| if (static_stream_collection_.UnblockFirstBlocked(&static_stream_id)) { |
| return static_stream_id; |
| } |
| |
| const auto id_and_precedence = |
| priority_write_scheduler_.PopNextReadyStreamAndPrecedence(); |
| const QuicStreamId id = std::get<0>(id_and_precedence); |
| const spdy::SpdyPriority priority = |
| std::get<1>(id_and_precedence).spdy3_priority(); |
| |
| if (!priority_write_scheduler_.HasReadyStreams()) { |
| // If no streams are blocked, don't bother latching. This stream will be |
| // the first popped for its priority anyway. |
| batch_write_stream_id_[priority] = 0; |
| last_priority_popped_ = priority; |
| } else if (batch_write_stream_id_[priority] != id) { |
| // If newly latching this batch write stream, let it write 16k. |
| batch_write_stream_id_[priority] = id; |
| bytes_left_for_batch_write_[priority] = 16000; |
| last_priority_popped_ = priority; |
| } |
| |
| return id; |
| } |
| |
| void RegisterStream(QuicStreamId stream_id, |
| bool is_static_stream, |
| spdy::SpdyPriority priority) { |
| DCHECK(!priority_write_scheduler_.StreamRegistered(stream_id)); |
| if (is_static_stream) { |
| static_stream_collection_.Register(stream_id); |
| return; |
| } |
| |
| priority_write_scheduler_.RegisterStream( |
| stream_id, spdy::SpdyStreamPrecedence(priority)); |
| } |
| |
| void UnregisterStream(QuicStreamId stream_id, bool is_static) { |
| if (is_static) { |
| static_stream_collection_.Unregister(stream_id); |
| return; |
| } |
| priority_write_scheduler_.UnregisterStream(stream_id); |
| } |
| |
| void UpdateStreamPriority(QuicStreamId stream_id, |
| spdy::SpdyPriority new_priority) { |
| DCHECK(!static_stream_collection_.IsRegistered(stream_id)); |
| priority_write_scheduler_.UpdateStreamPrecedence( |
| stream_id, spdy::SpdyStreamPrecedence(new_priority)); |
| } |
| |
| void UpdateBytesForStream(QuicStreamId stream_id, size_t bytes) { |
| if (batch_write_stream_id_[last_priority_popped_] == stream_id) { |
| // If this was the last data stream popped by PopFront, update the |
| // bytes remaining in its batch write. |
| bytes_left_for_batch_write_[last_priority_popped_] -= |
| static_cast<int32_t>(bytes); |
| } |
| } |
| |
| // Pushes a stream to the back of the list for its priority level *unless* it |
| // is latched for doing batched writes in which case it goes to the front of |
| // the list for its priority level. |
| // Headers and crypto streams are special cased to always resume first. |
| void AddStream(QuicStreamId stream_id) { |
| if (static_stream_collection_.SetBlocked(stream_id)) { |
| return; |
| } |
| |
| bool push_front = |
| stream_id == batch_write_stream_id_[last_priority_popped_] && |
| bytes_left_for_batch_write_[last_priority_popped_] > 0; |
| priority_write_scheduler_.MarkStreamReady(stream_id, push_front); |
| } |
| |
| // Returns true if stream with |stream_id| is write blocked. |
| bool IsStreamBlocked(QuicStreamId stream_id) const { |
| for (const auto& stream : static_stream_collection_) { |
| if (stream.id == stream_id) { |
| return stream.is_blocked; |
| } |
| } |
| |
| return priority_write_scheduler_.IsStreamReady(stream_id); |
| } |
| |
| private: |
| QuicPriorityWriteScheduler priority_write_scheduler_; |
| |
| // If performing batch writes, this will be the stream ID of the stream doing |
| // batch writes for this priority level. We will allow this stream to write |
| // until it has written kBatchWriteSize bytes, it has no more data to write, |
| // or a higher priority stream preempts. |
| QuicStreamId batch_write_stream_id_[spdy::kV3LowestPriority + 1]; |
| // Set to kBatchWriteSize when we set a new batch_write_stream_id_ for a given |
| // priority. This is decremented with each write the stream does until it is |
| // done with its batch write. |
| int32_t bytes_left_for_batch_write_[spdy::kV3LowestPriority + 1]; |
| // Tracks the last priority popped for UpdateBytesForStream. |
| spdy::SpdyPriority last_priority_popped_; |
| |
| // A StaticStreamCollection is a vector of <QuicStreamId, bool> pairs plus a |
| // eagerly-computed number of blocked static streams. |
| class StaticStreamCollection { |
| public: |
| struct StreamIdBlockedPair { |
| QuicStreamId id; |
| bool is_blocked; |
| }; |
| |
| // Optimized for the typical case of 2 static streams per session. |
| typedef QuicInlinedVector<StreamIdBlockedPair, 2> StreamsVector; |
| |
| StreamsVector::const_iterator begin() const { return streams_.cbegin(); } |
| |
| StreamsVector::const_iterator end() const { return streams_.cend(); } |
| |
| size_t num_blocked() const { return num_blocked_; } |
| |
| // Add |id| to the collection in unblocked state. |
| void Register(QuicStreamId id) { |
| DCHECK(!IsRegistered(id)); |
| DCHECK(streams_.empty() || id > streams_.back().id) |
| << "stream_id: " << id |
| << " last static stream: " << streams_.back().id; |
| streams_.push_back({id, false}); |
| } |
| |
| // True if |id| is in the collection, regardless of its state. |
| bool IsRegistered(QuicStreamId id) const { |
| for (const auto& stream : streams_) { |
| if (stream.id == id) { |
| return true; |
| } |
| } |
| return false; |
| } |
| |
| // Remove |id| from the collection, if it is in the blocked state, reduce |
| // |num_blocked_| by 1. |
| void Unregister(QuicStreamId id) { |
| for (auto it = streams_.begin(); it != streams_.end(); ++it) { |
| if (it->id == id) { |
| if (it->is_blocked) { |
| --num_blocked_; |
| } |
| streams_.erase(it); |
| return; |
| } |
| } |
| DCHECK(false) << "Erasing a non-exist stream with id " << id; |
| } |
| |
| // Set |id| to be blocked. If |id| is not already blocked, increase |
| // |num_blocked_| by 1. |
| // Return true if |id| is in the collection. |
| bool SetBlocked(QuicStreamId id) { |
| for (auto& stream : streams_) { |
| if (stream.id == id) { |
| if (!stream.is_blocked) { |
| stream.is_blocked = true; |
| ++num_blocked_; |
| } |
| return true; |
| } |
| } |
| return false; |
| } |
| |
| // Unblock the first blocked stream in the collection. |
| // If no stream is blocked, return false. Otherwise return true, set *id to |
| // the unblocked stream id and reduce |num_blocked_| by 1. |
| bool UnblockFirstBlocked(QuicStreamId* id) { |
| for (auto& stream : streams_) { |
| if (stream.is_blocked) { |
| --num_blocked_; |
| stream.is_blocked = false; |
| *id = stream.id; |
| return true; |
| } |
| } |
| return false; |
| } |
| |
| private: |
| size_t num_blocked_ = 0; |
| StreamsVector streams_; |
| }; |
| |
| StaticStreamCollection static_stream_collection_; |
| }; |
| |
| } // namespace quic |
| |
| #endif // NET_THIRD_PARTY_QUIC_CORE_QUIC_WRITE_BLOCKED_LIST_H_ |