1// Copyright 2014 The Go Authors. All rights reserved. 2// Use of this source code is governed by a BSD-style 3// license that can be found in the LICENSE file. 4 5package http2 6 7import "math" 8 9// NewRandomWriteScheduler constructs a WriteScheduler that ignores HTTP/2 10// priorities. Control frames like SETTINGS and PING are written before DATA 11// frames, but if no control frames are queued and multiple streams have queued 12// HEADERS or DATA frames, Pop selects a ready stream arbitrarily. 13func NewRandomWriteScheduler() WriteScheduler { 14 return &randomWriteScheduler{sq: make(map[uint32]*writeQueue)} 15} 16 17type randomWriteScheduler struct { 18 // zero are frames not associated with a specific stream. 19 zero writeQueue 20 21 // sq contains the stream-specific queues, keyed by stream ID. 22 // When a stream is idle or closed, it's deleted from the map. 23 sq map[uint32]*writeQueue 24 25 // pool of empty queues for reuse. 26 queuePool writeQueuePool 27} 28 29func (ws *randomWriteScheduler) OpenStream(streamID uint32, options OpenStreamOptions) { 30 // no-op: idle streams are not tracked 31} 32 33func (ws *randomWriteScheduler) CloseStream(streamID uint32) { 34 q, ok := ws.sq[streamID] 35 if !ok { 36 return 37 } 38 delete(ws.sq, streamID) 39 ws.queuePool.put(q) 40} 41 42func (ws *randomWriteScheduler) AdjustStream(streamID uint32, priority PriorityParam) { 43 // no-op: priorities are ignored 44} 45 46func (ws *randomWriteScheduler) Push(wr FrameWriteRequest) { 47 id := wr.StreamID() 48 if id == 0 { 49 ws.zero.push(wr) 50 return 51 } 52 q, ok := ws.sq[id] 53 if !ok { 54 q = ws.queuePool.get() 55 ws.sq[id] = q 56 } 57 q.push(wr) 58} 59 60func (ws *randomWriteScheduler) Pop() (FrameWriteRequest, bool) { 61 // Control frames first. 62 if !ws.zero.empty() { 63 return ws.zero.shift(), true 64 } 65 // Iterate over all non-idle streams until finding one that can be consumed. 66 for _, q := range ws.sq { 67 if wr, ok := q.consume(math.MaxInt32); ok { 68 return wr, true 69 } 70 } 71 return FrameWriteRequest{}, false 72} 73