1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 | 1× 1× 1× 1× 1× 1× 1× 572× 572× 572× 572× 572× 572× 572× 1× 1× 1× 10× 1× 45× 1× 5409× 5409× 5409× 5409× 3669× 3669× 3669× 3669× 3669× 1740× 1740× 1740× 1740× 1727× 13× 1740× 1740× 1740× 1× 12288× 4339× 7949× 2153× 5796× 5796× 5796× 5796× 5796× 1× 5796× 5796× 1× 5848× 5848× 5848× 5848× 3669× 3669× 3669× 4461× 4461× 3669× 3669× 529× 5848× 1× 5848× 5848× 5848× 4133× 1715× 1715× 1740× 1740× 1740× 1740× 1740× 1740× 1727× 1727× 11× 1727× 1740× 1740× 1882× 1882× 1740× 1740× 1567× 1740× 1715× 1× 52× 52× 52× 1× 1740× 1740× 1740× 1× 1740× 1× 1740× 1× 1740× | 'use strict' var transport = require('../../../spdy-transport') var utils = transport.utils var assert = require('assert') var util = require('util') var debug = require('debug')('spdy:scheduler') var Readable = require('readable-stream').Readable /* * We create following structure in `pending`: * [ [ id = 0 ], [ id = 1 ], [ id = 2 ], [ id = 0 ] ] * chunks chunks chunks chunks * chunks chunks * chunks * * Then on the `.tick()` pass we pick one chunks from each item and remove the * item if it is empty: * * [ [ id = 0 ], [ id = 2 ] ] * chunks chunks * chunks * * Writing out: chunks for 0, chunks for 1, chunks for 2, chunks for 0 * * This way data is interleaved between the different streams. */ function Scheduler (options) { Readable.call(this) // Pretty big window by default this.window = 0.25 Iif (options && options.window) { this.window = options.window } this.sync = [] this.list = [] this.count = 0 this.pendingTick = false } util.inherits(Scheduler, Readable) module.exports = Scheduler // Just for testing, really Scheduler.create = function create (options) { return new Scheduler(options) } function insertCompare (a, b) { return a.priority === b.priority ? a.stream - b.stream : b.priority - a.priority } Scheduler.prototype.schedule = function schedule (data) { var priority = data.priority var stream = data.stream var chunks = data.chunks // Synchronous frames should not be interleaved if (priority === false) { debug('queue sync', chunks) this.sync.push(data) this.count += chunks.length this._read() return } debug('queue async priority=%d stream=%d', priority, stream, chunks) var item = new SchedulerItem(stream, priority) var index = utils.binaryLookup(this.list, item, insertCompare) // Push new item if (index >= this.list.length || insertCompare(this.list[index], item) !== 0) { this.list.splice(index, 0, item) } else { // Coalesce item = this.list[index] } item.push(data) this.count += chunks.length this._read() } Scheduler.prototype._read = function _read () { if (this.count === 0) { return } if (this.pendingTick) { return } this.pendingTick = true var self = this process.nextTick(function () { self.pendingTick = false self.tick() }) } Scheduler.prototype.tick = function tick () { // No luck for async frames Iif (!this.tickSync()) { return false } return this.tickAsync() } Scheduler.prototype.tickSync = function tickSync () { // Empty sync queue first var sync = this.sync var res = true this.sync = [] for (var i = 0; i < sync.length; i++) { var item = sync[i] debug('tick sync pending=%d', this.count, item.chunks) for (var j = 0; j < item.chunks.length; j++) { this.count-- res = this.push(item.chunks[j]) } debug('after tick sync pending=%d', this.count) // TODO(indutny): figure out the way to invoke callback on actual write if (item.callback) { item.callback(null) } } return res } Scheduler.prototype.tickAsync = function tickAsync () { var res = true var list = this.list if (list.length === 0) { return res } var startPriority = list[0].priority for (var index = 0; list.length > 0; index++) { // Loop index index %= list.length if (startPriority - list[index].priority > this.window) { index = 0 } debug('tick async index=%d start=%d', index, startPriority) var current = list[index] var item = current.shift() if (current.isEmpty()) { list.splice(index, 1) if (index === 0 && list.length > 0) { startPriority = list[0].priority } index-- } debug('tick async pending=%d', this.count, item.chunks) for (var i = 0; i < item.chunks.length; i++) { this.count-- res = this.push(item.chunks[i]) } debug('after tick pending=%d', this.count) // TODO(indutny): figure out the way to invoke callback on actual write if (item.callback) { item.callback(null) } Iif (!res) { break } } return res } Scheduler.prototype.dump = function dump () { this.tickSync() // Write everything out while (!this.tickAsync()) { // Intentional no-op } assert.equal(this.count, 0) } function SchedulerItem (stream, priority) { this.stream = stream this.priority = priority this.queue = [] } SchedulerItem.prototype.push = function push (chunks) { this.queue.push(chunks) } SchedulerItem.prototype.shift = function shift () { return this.queue.shift() } SchedulerItem.prototype.isEmpty = function isEmpty () { return this.queue.length === 0 } |