The Tor Browser: comparison testing/xpcshell/node-http2/node_modules/http2-protocol/lib/connection.js

comparison: testing/xpcshell/node-http2/node_modules/http2-protocol/lib/connection.js

testing/xpcshell/node-http2/node_modules/http2-protocol/lib/connection.js

branch: TOR_BUG_9701
changeset 15: b8a032363ba2

equal deleted inserted replaced

--1:000000000000
+:77fdd17c34d2
+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;
+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) {
+if ((frame.type === 'SETTINGS') || (frame.type === 'PING') ||
+(frame.type === 'GOAWAY') || (frame.type === 'WINDOW_UPDATE')) {
+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;
+if (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;
+if (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);
+// 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 if ((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);
+// * handling stream errors as connection errors
+stream.on('error', 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) {
+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];
+}
+this._insert(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._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._allocatePriority(stream);
+return 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;
+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
+//   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];
+var frame = stream.upstream.read((this._window > 0) ? this._window : -1);
+if (!frame) {
+continue;
+} else if (frame.count_change > this._streamSlotsFree) {
+stream.upstream.unshift(frame);
+continue;
+}
+nextBucket.push(stream);
+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);
+assert(moreNeeded !== null); // The frame shouldn't be unforwarded
+if (moreNeeded === false) {
+break priority_loop;
+}
+}
+bucket = nextBucket;
+nextBucket = [];
+}
+}
+// * if we couldn't forward any frame, then sleep until window update, or some other wakeup event
+if (moreNeeded === undefined) {
+this.once('wakeup', this._send.bind(this));
+}
+this._log.trace({ moreNeeded: moreNeeded }, 'Stopping forwarding frames from streams.');
+};
+// The `_receive` method is another virtual method of the [Flow class](flow.html) that has to be
+// implemented by child classes. It forwards the given frame to the appropriate stream:
+Connection.prototype._receive = function _receive(frame, done) {
+this._log.trace({ frame: frame }, 'Forwarding incoming frame');
+// * first frame needs to be checked by the `_onFirstFrameReceived` method
+if (!this._firstFrameReceived) {
+this._firstFrameReceived = true;
+this._onFirstFrameReceived(frame);
+}
+// * gets the appropriate stream from the stream registry
+var stream = this._streamIds[frame.stream];
+// * or creates one if it's not in `this.streams`
+if (!stream) {
+stream = this._createIncomingStream(frame.stream);
+}
+// * in case of PUSH_PROMISE, replaces the promised stream id with a new incoming stream
+if (frame.type === 'PUSH_PROMISE') {
+frame.promised_stream = this._createIncomingStream(frame.promised_stream);
+}
+frame.count_change = this._changeStreamCount.bind(this);
+// * and writes it to the `stream`'s `upstream`
+stream.upstream.write(frame);
+done();
+};
+// Settings management
+// -------------------
+var defaultSettings = {
+};
+// Settings management initialization:
+Connection.prototype._initializeSettingsManagement = function _initializeSettingsManagement(settings) {
+// * Setting up the callback queue for setting acknowledgements
+this._settingsAckCallbacks = [];
+// * Sending the initial settings.
+this._log.debug({ settings: settings },
+'Sending the first SETTINGS frame as part of the connection header.');
+this.set(settings || defaultSettings);
+// * Forwarding SETTINGS frames to the `_receiveSettings` method
+this.on('SETTINGS', this._receiveSettings);
+};
+// * Checking that the first frame the other endpoint sends is SETTINGS
+Connection.prototype._onFirstFrameReceived = function _onFirstFrameReceived(frame) {
+if ((frame.stream === 0) && (frame.type === 'SETTINGS')) {
+this._log.debug('Receiving the first SETTINGS frame as part of the connection header.');
+} else {
+this._log.fatal({ frame: frame }, 'Invalid connection header: first frame is not SETTINGS.');
+this.emit('error');
+}
+};
+// Handling of incoming SETTINGS frames.
+Connection.prototype._receiveSettings = function _receiveSettings(frame) {
+// * If it's an ACK, call the appropriate callback
+if (frame.flags.ACK) {
+var callback = this._settingsAckCallbacks.shift();
+if (callback) {
+callback();
+}
+}
+// * If it's a setting change request, then send an ACK and change the appropriate settings
+else {
+if (!this._closed) {
+this.push({
+type: 'SETTINGS',
+flags: { ACK: true },
+stream: 0,
+settings: {}
+});
+}
+for (var name in frame.settings) {
+this.emit('RECEIVING_' + name, frame.settings[name]);
+}
+}
+};
+// Changing one or more settings value and sending out a SETTINGS frame
+Connection.prototype.set = function set(settings, callback) {
+// * Calling the callback and emitting event when the change is acknowledges
+callback = callback || function noop() {};
+var self = this;
+this._settingsAckCallbacks.push(function() {
+for (var name in settings) {
+self.emit('ACKNOWLEDGED_' + name, settings[name]);
+}
+callback();
+});
+// * Sending out the SETTINGS frame
+this.push({
+type: 'SETTINGS',
+flags: { ACK: false },
+stream: 0,
+settings: settings
+});
+for (var name in settings) {
+this.emit('SENDING_' + name, settings[name]);
+}
+};
+// Lifecycle management
+// --------------------
+// The main responsibilities of lifecycle management code:
+//
+// * keeping the connection alive by
+//   * sending PINGs when the connection is idle
+//   * answering PINGs
+// * ending the connection
+Connection.prototype._initializeLifecycleManagement = function _initializeLifecycleManagement() {
+this._pings = {};
+this.on('PING', this._receivePing);
+this.on('GOAWAY', this._receiveGoaway);
+this._closed = false;
+};
+// Generating a string of length 16 with random hexadecimal digits
+Connection.prototype._generatePingId = function _generatePingId() {
+do {
+var id = '';
+for (var i = 0; i < 16; i++) {
+id += Math.floor(Math.random()*16).toString(16);
+}
+} while(id in this._pings);
+return id;
+};
+// Sending a ping and calling `callback` when the answer arrives
+Connection.prototype.ping = function ping(callback) {
+var id = this._generatePingId();
+var data = new Buffer(id, 'hex');
+this._pings[id] = callback;
+this._log.debug({ data: data }, 'Sending PING.');
+this.push({
+type: 'PING',
+flags: {
+ACK: false
+},
+stream: 0,
+data: data
+});
+};
+// Answering pings
+Connection.prototype._receivePing = function _receivePing(frame) {
+if (frame.flags.ACK) {
+var id = frame.data.toString('hex');
+if (id in this._pings) {
+this._log.debug({ data: frame.data }, 'Receiving answer for a PING.');
+var callback = this._pings[id];
+if (callback) {
+callback();
+}
+delete this._pings[id];
+} else {
+this._log.warn({ data: frame.data }, 'Unsolicited PING answer.');
+}
+} else {
+this._log.debug({ data: frame.data }, 'Answering PING.');
+this.push({
+type: 'PING',
+flags: {
+ACK: true
+},
+stream: 0,
+data: frame.data
+});
+}
+};
+// Terminating the connection
+Connection.prototype.close = function close(error) {
+if (this._closed) {
+this._log.warn('Trying to close an already closed connection');
+return;
+}
+this._log.debug({ error: error }, 'Closing the connection');
+this.push({
+type: 'GOAWAY',
+flags: {},
+stream: 0,
+last_stream: this._lastIncomingStream,
+error: error || 'NO_ERROR'
+});
+this.push(null);
+this._closed = true;
+};
+Connection.prototype._receiveGoaway = function _receiveGoaway(frame) {
+this._log.debug({ error: frame.error }, 'Other end closed the connection');
+this.push(null);
+this._closed = true;
+if (frame.error !== 'NO_ERROR') {
+this.emit('peerError', frame.error);
+}
+};
+// Flow control
+// ------------
+Connection.prototype._initializeFlowControl = function _initializeFlowControl() {
+// Handling of initial window size of individual streams.
+this._initialStreamWindowSize = INITIAL_STREAM_WINDOW_SIZE;
+this.on('new_stream', function(stream) {
+stream.upstream.setInitialWindow(this._initialStreamWindowSize);
+});
+this.on('RECEIVING_SETTINGS_INITIAL_WINDOW_SIZE', this._setInitialStreamWindowSize);
+this._streamIds[0].upstream.setInitialWindow = function noop() {};
+};
+// The initial connection flow control window is 65535 bytes.
+var INITIAL_STREAM_WINDOW_SIZE = 65535;
+// A SETTINGS frame can alter the initial flow control window size for all current streams. When the
+// value of SETTINGS_INITIAL_WINDOW_SIZE changes, a receiver MUST adjust the window size of all
+// stream by calling the `setInitialStreamWindowSize` method. The window size has to be modified by
+// the difference between the new value and the old value.
+Connection.prototype._setInitialStreamWindowSize = function _setInitialStreamWindowSize(size) {
+if ((this._initialStreamWindowSize === Infinity) && (size !== Infinity)) {
+this._log.error('Trying to manipulate initial flow control window size after flow control was turned off.');
+this.emit('error', 'FLOW_CONTROL_ERROR');
+} else {
+this._log.debug({ size: size }, 'Changing stream initial window size.');
+this._initialStreamWindowSize = size;
+this._streamIds.forEach(function(stream) {
+stream.upstream.setInitialWindow(size);
+});
+}
+};