| // Copyright 2014 The Go Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style |
| // license that can be found in the LICENSE file. |
| |
| package http2 |
| |
| import "math" |
| |
| // NewRandomWriteScheduler constructs a WriteScheduler that ignores HTTP/2 |
| // priorities. Control frames like SETTINGS and PING are written before DATA |
| // frames, but if no control frames are queued and multiple streams have queued |
| // HEADERS or DATA frames, Pop selects a ready stream arbitrarily. |
| func NewRandomWriteScheduler() WriteScheduler { |
| return &randomWriteScheduler{sq: make(map[uint32]*writeQueue)} |
| } |
| |
| type randomWriteScheduler struct { |
| // zero are frames not associated with a specific stream. |
| zero writeQueue |
| |
| // sq contains the stream-specific queues, keyed by stream ID. |
| // When a stream is idle, closed, or emptied, it's deleted |
| // from the map. |
| sq map[uint32]*writeQueue |
| |
| // pool of empty queues for reuse. |
| queuePool writeQueuePool |
| } |
| |
| func (ws *randomWriteScheduler) OpenStream(streamID uint32, options OpenStreamOptions) { |
| // no-op: idle streams are not tracked |
| } |
| |
| func (ws *randomWriteScheduler) CloseStream(streamID uint32) { |
| q, ok := ws.sq[streamID] |
| if !ok { |
| return |
| } |
| delete(ws.sq, streamID) |
| ws.queuePool.put(q) |
| } |
| |
| func (ws *randomWriteScheduler) AdjustStream(streamID uint32, priority PriorityParam) { |
| // no-op: priorities are ignored |
| } |
| |
| func (ws *randomWriteScheduler) Push(wr FrameWriteRequest) { |
| id := wr.StreamID() |
| if id == 0 { |
| ws.zero.push(wr) |
| return |
| } |
| q, ok := ws.sq[id] |
| if !ok { |
| q = ws.queuePool.get() |
| ws.sq[id] = q |
| } |
| q.push(wr) |
| } |
| |
| func (ws *randomWriteScheduler) Pop() (FrameWriteRequest, bool) { |
| // Control frames first. |
| if !ws.zero.empty() { |
| return ws.zero.shift(), true |
| } |
| // Iterate over all non-idle streams until finding one that can be consumed. |
| for streamID, q := range ws.sq { |
| if wr, ok := q.consume(math.MaxInt32); ok { |
| if q.empty() { |
| delete(ws.sq, streamID) |
| ws.queuePool.put(q) |
| } |
| return wr, true |
| } |
| } |
| return FrameWriteRequest{}, false |
| } |