cubefs

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