node-http2

<!doctype html> <html lang="en"> <head> <title>Code coverage report for lib/protocol/connection.js</title> <meta charset="utf-8" /> <link rel="stylesheet" href="../../prettify.css" /> <link rel="stylesheet" href="../../base.css" /> <meta name="viewport" content="width=device-width, initial-scale=1"> <style type='text/css'> .coverage-summary .sorter { background-image: url(../../sort-arrow-sprite.png); } </style> </head> <body> <div class='wrapper'> <div class='pad1'> <h1> <a href="../../index.html">all files</a> / <a href="index.html">lib/protocol/</a> connection.js </h1> <div class='clearfix'> <div class='fl pad1y space-right2'> 89.37% Statements 227/254 </div> <div class='fl pad1y space-right2'> 76.36% Branches 84/110 </div> <div class='fl pad1y space-right2'> 96.97% Functions 32/33 </div> <div class='fl pad1y space-right2'> 89.72% Lines 227/253 </div> </div> </div> <div class='status-line high'></div> <pre><table class="coverage"> <tr><td class="line-count quiet">1 2 3 4 5 6 7 8 9 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  1× 5× 2× 2× 2× 2× 2× 2×   2×           3× 3×                       1× 2×         2× 2×             2× 2×     1× 2× 2× 2× 2×               1×   52× 52× 265×   52× 52×       1×           1× 18×       18× 18× 18× 18×        </td><td class="text"><pre class="prettyprint lang-js">var assert = require('assert');   // The Connection class // ====================   // The Connection class manages HTTP/2 connections. Each instance corresponds to one transport // stream (TCP stream). It operates by sending and receiving frames and is implemented as a // [Flow](flow.html) subclass.   var Flow = require('./flow').Flow; var timers = require('timers');   exports.Connection = Connection;   // Public API // ----------   // * **new Connection(log, firstStreamId, settings)**: create a new Connection // // * **Event: 'error' (type)**: signals a connection level error made by the other end // // * **Event: 'peerError' (type)**: signals the receipt of a GOAWAY frame that contains an error // code other than NO_ERROR // // * **Event: 'stream' (stream)**: signals that there's an incoming stream // // * **createStream(): stream**: initiate a new stream // // * **set(settings, callback)**: change the value of one or more settings according to the // key-value pairs of `settings`. The callback is called after the peer acknowledged the changes. // // * **ping([callback])**: send a ping and call callback when the answer arrives // // * **close([error])**: close the stream with an error code   // Constructor // -----------   // The main aspects of managing the connection are: function Connection(log, firstStreamId, settings) { // * initializing the base class Flow.call(this, 0);   // * logging: every method uses the common logger object this._log = log.child({ component: 'connection' });   // * stream management this._initializeStreamManagement(firstStreamId);   // * lifecycle management this._initializeLifecycleManagement();   // * flow control this._initializeFlowControl();   // * settings management this._initializeSettingsManagement(settings);   // * multiplexing this._initializeMultiplexing(); } Connection.prototype = Object.create(Flow.prototype, { constructor: { value: Connection } });   // Overview // --------   // | ^ | ^ // v | v | // +--------------+ +--------------+ // +---| stream1 |---| stream2 |---- .... ---+ // | | +----------+ | | +----------+ | | // | | | stream1. | | | | stream2. | | | // | +-| upstream |-+ +-| upstream |-+ | // | +----------+ +----------+ | // | | ^ | ^ | // | v | v | | // | +-----+-------------+-----+-------- .... | // | ^ | | | | // | | v | | | // | +--------------+ | | | // | | stream0 | | | | // | | connection | | | | // | | management | multiplexing | // | +--------------+ flow control | // | | ^ | // | _read() | | _write() | // | v | | // | +------------+ +-----------+ | // | |output queue| |input queue| | // +----------------+------------+-+-----------+-----------------+ // | ^ // read() | | write() // v |   // Stream management // -----------------   var Stream = require('./stream').Stream;   // Initialization: Connection.prototype._initializeStreamManagement = function _initializeStreamManagement(firstStreamId) { // * streams are stored in two data structures: // * `_streamIds` is an id -> stream map of the streams that are allowed to receive frames. // * `_streamPriorities` is a priority -> [stream] map of stream that allowed to send frames. this._streamIds = []; this._streamPriorities = [];   // * The next outbound stream ID and the last inbound stream id this._nextStreamId = firstStreamId; this._lastIncomingStream = 0;   // * Calling `_writeControlFrame` when there's an incoming stream with 0 as stream ID this._streamIds[0] = { upstream: { write: this._writeControlFrame.bind(this) } };   // * By default, the number of concurrent outbound streams is not limited. The `_streamLimit` can // be set by the SETTINGS_MAX_CONCURRENT_STREAMS setting. this._streamSlotsFree = Infinity; this._streamLimit = Infinity; this.on('RECEIVING_SETTINGS_MAX_CONCURRENT_STREAMS', this._updateStreamLimit); };   // `_writeControlFrame` is called when there's an incoming frame in the `_control` stream. It // broadcasts the message by creating an event on it. Connection.prototype._writeControlFrame = function _writeControlFrame(frame) { Eif ((frame.type === 'SETTINGS') || (frame.type === 'PING') || (frame.type === 'GOAWAY') || (frame.type === 'WINDOW_UPDATE') || (frame.type === 'ALTSVC')) { this._log.debug({ frame: frame }, 'Receiving connection level frame'); this.emit(frame.type, frame); } else { this._log.error({ frame: frame }, 'Invalid connection level frame'); this.emit('error', 'PROTOCOL_ERROR'); } };   // Methods to manage the stream slot pool: Connection.prototype._updateStreamLimit = function _updateStreamLimit(newStreamLimit) { var wakeup = (this._streamSlotsFree === 0) && (newStreamLimit > this._streamLimit); this._streamSlotsFree += newStreamLimit - this._streamLimit; this._streamLimit = newStreamLimit; Iif (wakeup) { this.emit('wakeup'); } };   Connection.prototype._changeStreamCount = function _changeStreamCount(change) { if (change) { this._log.trace({ free: this._streamSlotsFree, change: change }, 'Changing active stream count.'); var wakeup = (this._streamSlotsFree === 0) && (change < 0); this._streamSlotsFree -= change; Iif (wakeup) { this.emit('wakeup'); } } };   // Creating a new *inbound or outbound* stream with the given `id` (which is undefined in case of // an outbound stream) consists of three steps: // // 1. var stream = new Stream(this._log, this); // 2. this._allocateId(stream, id); // 2. this._allocatePriority(stream);   // Allocating an ID to a stream Connection.prototype._allocateId = function _allocateId(stream, id) { // * initiated stream without definite ID if (id === undefined) { id = this._nextStreamId; this._nextStreamId += 2; }   // * incoming stream with a legitim ID (larger than any previous and different parity than ours) else Eif ((id > this._lastIncomingStream) && ((id - this._nextStreamId) % 2 !== 0)) { this._lastIncomingStream = id; }   // * incoming stream with invalid ID else { this._log.error({ stream_id: id, lastIncomingStream: this._lastIncomingStream }, 'Invalid incoming stream ID.'); this.emit('error', 'PROTOCOL_ERROR'); return undefined; }   assert(!(id in this._streamIds));   // * adding to `this._streamIds` this._log.trace({ s: stream, stream_id: id }, 'Allocating ID for stream.'); this._streamIds[id] = stream; stream.id = id; this.emit('new_stream', stream, id);   // * forwarding connection errors from streams stream.on('connectionError', this.emit.bind(this, 'error'));   return id; };   // Allocating a priority to a stream, and managing priority changes Connection.prototype._allocatePriority = function _allocatePriority(stream) { this._log.trace({ s: stream }, 'Allocating priority for stream.'); this._insert(stream, stream._priority); stream.on('priority', this._reprioritize.bind(this, stream)); stream.upstream.on('readable', this.emit.bind(this, 'wakeup')); this.emit('wakeup'); };   Connection.prototype._insert = function _insert(stream, priority) { if (priority in this._streamPriorities) { this._streamPriorities[priority].push(stream); } else { this._streamPriorities[priority] = [stream]; } };   Connection.prototype._reprioritize = function _reprioritize(stream, priority) { this._removePrioritisedStream(stream); this._insert(stream, priority); };   Connection.prototype._removePrioritisedStream = function _removePrioritisedStream(stream) { var bucket = this._streamPriorities[stream._priority]; var index = bucket.indexOf(stream); assert(index !== -1); bucket.splice(index, 1); if (bucket.length === 0) { delete this._streamPriorities[stream._priority]; } };   // Creating an *inbound* stream with the given ID. It is called when there's an incoming frame to // a previously nonexistent stream. Connection.prototype._createIncomingStream = function _createIncomingStream(id) { this._log.debug({ stream_id: id }, 'New incoming stream.');   var stream = new Stream(this._log, this); this._allocateId(stream, id); this._allocatePriority(stream); this.emit('stream', stream, id);   return stream; };   // Creating an *outbound* stream Connection.prototype.createStream = function createStream() { this._log.trace('Creating new outbound stream.');   // * Receiving is enabled immediately, and an ID gets assigned to the stream var stream = new Stream(this._log, this); this._allocatePriority(stream);   stream.on('end', this._removeStream.bind(this, stream));   return stream; };   Connection.prototype._removeStream = function _removeStream(stream) { this._log.trace('Removing outbound stream.');   delete this._streamIds[stream.id]; this._removePrioritisedStream(stream); };   // Multiplexing // ------------   Connection.prototype._initializeMultiplexing = function _initializeMultiplexing() { this.on('window_update', this.emit.bind(this, 'wakeup')); this._sendScheduled = false; this._firstFrameReceived = false; };   // The `_send` method is a virtual method of the [Flow class](flow.html) that has to be implemented // by child classes. It reads frames from streams and pushes them to the output buffer. Connection.prototype._send = function _send(immediate) { // * Do not do anything if the connection is already closed if (this._closed) { return; }   // * Collapsing multiple calls in a turn into a single deferred call if (immediate) { this._sendScheduled = false; } else { if (!this._sendScheduled) { this._sendScheduled = true; timers.setImmediate(this._send.bind(this, true)); } return; }   this._log.trace('Starting forwarding frames from streams.');   // * Looping through priority `bucket`s in priority order. priority_loop: for (var priority in this._streamPriorities) { var bucket = this._streamPriorities[priority]; var nextBucket = [];   // * Forwarding frames from buckets with round-robin scheduling. // 1. pulling out frame // 2. if there's no frame, skip this stream // 3. if forwarding this frame would make `streamCount` greater than `streamLimit`, skip // this stream // 4. adding stream to the bucket of the next round unless it has ended // 5. assigning an ID to the frame (allocating an ID to the stream if there isn't already) // 6. if forwarding a PUSH_PROMISE, allocate ID to the promised stream // 7. forwarding the frame, changing `streamCount` as appropriate // 8. stepping to the next stream if there's still more frame needed in the output buffer // 9. switching to the bucket of the next round while (bucket.length > 0) { for (var index = 0; index < bucket.length; index++) { var stream = bucket[index]; Iif(!stream || !stream.upstream) continue; var frame = stream.upstream.read((this._window > 0) ? this._window : -1);   if (!frame) { continue; } else Iif (frame.count_change > this._streamSlotsFree) { stream.upstream.unshift(frame); continue; }   if (!stream._ended) { nextBucket.push(stream); } else { delete this._streamIds[stream.id]; }   if (frame.stream === undefined) { frame.stream = stream.id || this._allocateId(stream); }   if (frame.type === 'PUSH_PROMISE') { this._allocatePriority(frame.promised_stream); frame.promised_stream = this._allocateId(frame.promised_stream); }   this._log.trace({ s: stream, frame: frame }, 'Forwarding outgoing frame'); var moreNeeded = this.push(frame); this._changeStreamCount(frame.count_change);   <span class="missing-if-branch" title="if path no